ML15076A073

Palo Verde, Units 1, 2, and 3 - Seismic Hazard and Screening Report

ML15076A073
Person / Time
Site:	Palo Verde
Issue date:	03/10/2015
From:	Cadogan J J Arizona Public Service Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
102-07010-JJC/TNW/PJH
Download: ML15076A073 (100)

Text

411Qaps10 CFR 50.54(f)JOHN 3. CADOGAN, JRVice President Engineering Palo VerdeNuclear Generating StationP.O. Box 52034Phoenix, AZ 85072Mail Station 7602Tel 623 393 5553102-070 10-JJC/TNW/PJ HMarch 10, 2015U.S. Nuclear Regulatory Commission ATTN: Document Control Desk11555 Rockville PikeRockville, MD 20852Reference, NRC Letter, Request for Information Pursuant to Title 10 of the Codeof Federal Regulations 50.54(f)

Regarding Recommendations 2.1,2.3, and 9.3, of the Near-Term Task Force Review of Insights fromthe Fukushima Dai-ichi

Accident, dated March 12, 2012

Subject:

Palo Verde Nuclear Generating Station (PVNGS)Units 1, 2, and 3Docket Nos. STN 50-528, 50-529, and 50-530Seismic Hazard and Screening ReportIn accordance with the NRC request for information in the reference letter, enclosedis the Seismic Hazard and Screening Report for Palo Verde Nuclear Generating Station Units 1, 2, and 3, which documents the results of the seismic hazardevaluation performed for Arizona Public Service Company (APS).The PVNGS structural design bounds the reevaluated seismic hazard ground motionresponse spectrum (GMRS), therefore, no further evaluations or interim actions areneeded or required for the Near Term Task Force (NTTF) Recommendation 2.1seismic review.No commitments are being made to the NRC by this letter. Should you need furtherinformation regarding this submittal, please contact Thomas Weber, Department Leader, Regulatory

Affairs, at (623) 393-5764.

I declare under penalty of perjury that the foregoing is true and correct.31 lol I 1ý-Executed on(Date)Sincerely, JJC/TNW/pjh A-0 10A member of the STARS (Strategic Teaming and Resource Sharing)

AllianceCallaway

• Diablo Canyon

• Palo Verde

• Wolf Creek

" I02-07010-JJC/TNW ATTN: Document Control DeskU.S. Nuclear Regulatory Commission Seismic Hazard and Screening ReportPage 2

Enclosure:

Seismic Hazard and Screening Report for the Palo Verde NuclearGenerating Station Units 1, 2, and 3, March 2015cc: W. M. DeanM. L. DapasB. K. SingalM. M. WatfordC. A. PeabodyN. J. DiFrancesco NRC Director Office of Nuclear Reactor Regulation NRC Region IV Regional Administrator NRC NRR Project Manager for PVNGSNRC NRR Project ManagerNRC Senior Resident Inspector PVNGSNRC JLD Project Manager SEISMIC HAZARD ANDSCREENING REPORTfor thePALO VERDE NUCLEAR GENERATING STATIONUNITS 1, 2, AND 3REVISION 0MARCH 2015I Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3ContentsI In tro d u ctio n .............................................................................................................................

32 Seism ic Hazard Reevaluation

..............................................................................................

42.1 Regional and Local Geology .....................................................................................

42.2 Probabilistic Seism ic Hazard Analysis

........................................................................

62.2.1 Overview of SSHAC Process ..................................................................................

62.2.2 Sum mary of Seism ic Source Characterization (SSC) M odel .....................................

72.2.3 Summary of Ground Motion Characterization (GMC) Model ...................................

102.2.4 Sum mary of PSHA Implementation

.......................................................................

152.2.5 Mean Site Specific Rock Hazard Curves for Major Contributing Sources ..................

172.2.6 Total M ean Seismic Site Specific Rock Hazard Curves ...........................................

312.3 Site Response Evaluation

.......................................................................................

322.3.1 Description of Subsurface M aterial .......................................................................

322.3.2 Development of Base Case Profiles and Nonlinear Material Properties

.....................

332.3.3 Random ization of Shear W ave Velocity Profiles

....................................................

462.3.4 Input Spectra ...........................................................................................................

462.3.5 M ethodology

...........................................................................................................

482.3.6 Amplification Functions

......................................................................................

492.4 Soil Hazard and Ground Motion Response Spectrum (GMRS) Calculations

..........

562.4.1 Background

.............................................................................................................

562.4.2 M ethodology

...........................................................................................................

562 .4 .3 R esu lts ....................................................................................................................

5 73 Plant Design Basis ..................................................................................................................

633.1 SSE Description of Spectral Shape ..........................................................................

633.2 Control Point Elevation

............................................................................................

644 Screening Evaluation

..............................................................................................................

654.1 Risk Evaluation Screening (1 to 10 Hz) ..................................................................

654.2 High Frequency Screening

(>10 Hz) .......................................................................

664.3 Spent Fuel Pool Evaluation Screening (1 to 10 Hz) ................................................

665 Interim Actions ......................................................................................................................

666 Conclusions

...........................................................................................................................

667 R eferen ces .............................................................................................................................

6 61 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3A ppendix A .T abulated D ata ..........................................................................................................

70Appendix B SSC PPRP Endorsement Letter ................................................................................

80Appendix C GMC PPRP Endorsement Letter ..............................................................................

85Appendix D SWUS GMC Project Letter ....................................................................................

90Appendix E GMC PPRP Endorsement Letter Revision 2 .............................................................

922 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 31 Introduction Following the accident at the Fukushima Daiichi nuclear power plant resulting from the March H1, 2011,Great Tohoku Earthquake and subsequent

tsunami, the United States Nuclear Regulatory Commission (U.S.NRC) established a Near Term Task Force (NTTF) to conduct a systematic review of NRCprocesses and regulations and to determine if the agency should make additional improvements to itsregulatory system. The NTTF developed a set of recommendations intended to clarify and strengthen theregulatory framework for protection against natural phenomena.

Subsequently, the NRC issued a 10 CFR50.54(f) letter, Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f)Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from theFukushima Dai-Ichi

Accident, (U.S.NRC, 2012a) that requests information to assure that theserecommendations are addressed by all U.S. nuclear power plants. The 10 CFR 50.54(f) letter requeststhat licensees and holders of construction permits under 10 CFR Part 50 reevaluate the seismic hazards attheir sites against present-day NRC requirements.

Depending on the comparison between the reevaluated seismic hazard and the current design basis, the result is either no further risk evaluation or theperformance of a seismic risk assessment.

Risk assessment approaches acceptable to the staff include aseismic probabilistic risk assessment (SPRA), or a seismic margin assessment (SMA). Based upon thisinformation, the NRC staff will determine whether additional regulatory actions are necessary.

This report provides the information requested in items (1) through (7) of the "Requested Information" section and Attachment I of the 10 CFR 50.54(f) letter pertaining to NTTF Recommendation 2.1 for thePalo Verde Nuclear Generating Station (PVNGS),

located in in Maricopa County, Arizona.

In providing this information, Arizona Public Service Company (APS) followed the guidance provided in the SeismicEvaluation Guidance:

Screening, Prioritization, and Implementation Details (SPID) for the Resolution ofFukushima Near-Term Task Force Recommendation 2.1: Seismic (EPRI, 2013). The Augmented

Approach, Seismic Evaluation Guidance:

Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic (EPRI, 2013a), has been developed as the process forevaluating critical plant equipment prior to performing the complete plant seismic risk evaluations.

The original geologic and seismic siting investigations for PVNGS were performed in accordance withAppendix A to 10 CFR Part 100 and meet General Design Criterion 2 in Appendix A to 10 CFR Part 50.The Safe Shutdown Earthquake Ground Motion (SSE) was developed in accordance with Appendix A to10 CFR Part 100 and is bounded by the design of Seismic Category 1 structures, systems andcomponents.

In response to the 10 CFR 50.54(f) letter and following the guidance provided in the SPID (EPRI, 2013),a seismic hazard reevaluation for the PVNGS site was performed.

For screening

purposes, a GroundMotion Response Spectrum (GMRS) was developed.

Based on the results of the screening evaluation, the PVNGS Design Spectral Response Curve used forthe design of Seismic Category I Structures.,

Systems and Components (SSCs) exceeds the GMRS curvein the I to 10 Hz frequency range and in the frequency range above 10 Hz; therefore, no further action isrequired for the NTTF Recommendation 2.1 seismic review.3 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 32 Seismic Hazard Reevaluation The plant description is provided in the PVNGS Updated Final Safety Analysis Report (UFSAR, Rev.17). PVNGS is located in Maricopa County, Arizona, approximately 34 miles west of the nearestboundary of the city of Phoenix (UFSAR, Rev. 17 Section 2.5). The PVNGS site essentially consists of arelatively thin veneer of dense cohesionless soils, 30 to 60 feet in thickness, underlain by about 250 feetof stiff to hard clays. Cohesionless soils include layers and lenses of sands with some gravels, silty sands,clayey sands, and silts. A third general material type, granular

backfill, was placed beneath and adjacentto some Seismic Category I structures.

The level of maximum vibratory ground motion that might occur at the site was determined byconsidering the largest earthquakes that might credibly occur in each of the following seismic zones:* Seismic Zone A is the concentration of activity in the southwest quadrant from the site atdistances beyond about 120 miles.* Seismic Zone B is a roughly circular zone of epicenters about 80 miles in diameter and lyingastride the Arizona-Sonora border." Seismic Zone C is a band of rather diffuse seismicity extending diagonally across Arizona fromits northwest corner. Zone C corresponds to a transition zone between the Colorado Plateau to thenortheast and the Sonoran Desert portion of the Basin and Range province to the southwest.

• The remainder of the region within 200 miles of the site has very sparse seismic activity and istermed Zone D. Seismic Zone D generally corresponds to the Sonora Desert portion of the Basinand Range province.

" Seismic Zone E is a band of seismicity trending northwestward across southern Nevada and intocentral Utah. This zone is about 100 miles wide and has been called the Southern NevadaTransverse Zone. Zone E was included because it bounds the site zone and separates the site zonefrom Nevada Basin and Range tectonics further to the north.When attenuation of strong ground motions because of distance from the epicenter was considered, themost severe case at the site was found to be the postulated (hypothetical) occurrence of a Sonora-type (1887) earthquake located 72 miles from the site (Zone C). The 10 CFR Part 100, Appendix A sitecharacterization safe shutdown earthquake (SSE) vibratory ground motion associated with this event wasfound to be conservatively represented by horizontal and vertical design response spectra normalized to0.20g with the characteristics recommended in NRC Regulatory Guide 1.60 (U.S.NRC, 1973) designspectra.

These design spectra were judged to be a very conservative envelope of the level of groundshaking to be expected at the site due to an earthquake of magnitude 8.0 at a distance of 72 miles.2.1 Regional and Local GeologyThe PVNGS site is located in western Arizona near the city of Tonopah (Figure 1), within the SouthernBasin and Range physiographic province.

The region surrounding the site has a complex geologic historyassociated with three major phases of deformation along the western margin of the North Americancontinent.

These phases include (1) east-directed subduction of portions of the Farallon plate beneath theNorth American plate and subsequent orogenesis during Mesozoic and Cenozoic time, (2) multiple phasesof Basin and Range extension from the Eocene to the late Miocene, and (3) a late Miocene to Recent4 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3phase of transform faulting and extension to accommodate oblique divergence between the Pacific andNorth American plates.W6 N133 N30" NFigure 1. Physiographic provinces in the region surrounding the PVNGS site. Black star indicates thelocation of the PVNGS site. Source: (APS, 2015).The Southern Basin and Range physiographic province is generally characterized by discontinuous northwest to east-northeast trending mountain ranges flanked by extensive bedrock pediments, withintervening sedimentary basins that can be as much as 30 km wide (Menges and Pearthree, 1989). Thistopography expresses post-Laramide epeirogenic extension, which comprises normal-fault-bounded grabens and half-grabens.

Very few geologic slip rates are published for faults in this province, butavailable data indicate that Southern Basin and Range normal faults are characterized by very slow sliprates and long recurrence intervals (Pearthree et al., 1983).Within the PVNGS Site Region (320-km radius),

the Southern Basin and Range physiographic provinceis characterized by low rates of seismicity and low to moderate magnitude historical earthquakes.

Thesparse and diffuse pattern of earthquakes does not form lineaments coincident with known faults, anddoes not indicate the presence of unmapped faults. Beyond the Site Region the largest historical earthquake in the Southern Basin and Range physiographic province is the 1887 Sonoran earthquake.

This moment magnitude (M) -7.5 earthquake was located more than 400 km southeast of the PVNGS site(e.g., Suter and Contreras, 2002; Suter, 2006). The Northern Basin and Range Province in central and5 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3northern Nevada, well outside the Site Region, also has had several large, historical surface-rupturing earthquakes, including the 1915 M7.2 Pleasant Valley and 1954 M7.1 Fairview Peak earthquakes (e.g.,Stover and Coffman, 1993).The nearest mapped Quaternary fault to the PVNGS site is the Sand Tank fault, which lies about 60 km tothe south-southwest.

This fault is characterized by an approximately 2m high fault scarp on Pleistocene alluvium that extends for approximately 3.5 km. Demsey and Pearthree (Demsey and Pearthree 1990),however, speculate that the fault may extend for as much as 32 km based on tonal lineaments.

Demseyand Pearthree's (1990) preferred interpretation is that this scarp formed during a single earthquake thatoccurred between about 8,000 and 20,000 years ago.Major dextral strike-slip faults associated with the Pacific-North American plate boundary are locatedabout 240 to 300 km west of the PVNGS site. These include the San Andreas, San Jacinto, Cerro Prieto,and other faults, all of which have high slip rates and have produced repeated moderate and largemagnitude earthquakes in the Holocene Epoch. The closest of these faults is the San Andreas fault, whichat its nearest point lies about 240 km west of the PVNGS site.The geologic materials underlying Units 1, 2, and 3 at the PVNGS site include about 350 ft of basinsediments overlying bedrock.

Basin sediments include stratigraphic subdivisions of sands, gravels, clays,silts, and fanglomerate.

Bedrock consists of Miocene volcanic and interbedded sedimentary rocks. Thebasement complex comprises Precambrian granitic and metamorphic rocks and has been encountered at adepth of about 1,200 feet below the ground surface in the site area (UFSAR, Rev. 17). Section 2.3 of thisreport provides additional detail regarding the subsurface geologic materials at the PVNGS site.2.2 Probabilistic Seismic Hazard AnalysisA Probabilistic Seismic Hazard Analysis (PSHA) was conducted for PVNGS using updated SeismicSource Characterization (SSC) and Ground Motion Characterization (GMC) models as primary inputs.The SSC model describes the future potential for earthquakes (e.g., magnitudes, locations, and rates) inthe region surrounding the PVNGS site, and the GMC model describes the distribution of the groundmotion as a function of earthquake magnitude, style of faulting, source-to-site

geometry, and siteconditions.

2.2.1 Overview of SSHAC ProcessIn accordance with 10 CFR 50.54(f) letter (U.S.NRC, 2012a), the SSC and GMC models were developed using Senior Seismic Hazard Analysis Committee (SSHAC) Level 3 procedures described inNUREG/CR-6372 (Budnitz et al., 1997), and the detailed implementation guidance provided in NUREG2117 (U.S.NRC, 2012b). The goal of following the SSHAC Level 3 process is to provide reasonable regulatory assurance that the center, body, and range of the technically defensible interpretations havebeen adequately captured in the SSC and GMC models. Thus, the SSC and GMC studies were planned,conducted, and reviewed in strict compliance with the SSHAC Level 3 procedures.

The four main components of the SSHAC process are: (1) evaluation of data and methods; (2) integration of data and methods in model development; (3) documentation of the SS1HAC process and modelingdecisions; and (4) participatory peer review. The SSC and GMC models were developed by separate butparallel SSHAC Level 3 studies, and each underwent ongoing review by each model's respective Participatory Peer Review Panel (PPRP). Following review of the final reports, each PPRP issued aclosure letter summarizing their perspective of the respective SSHAC Level 3 study. The letters describe6 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3the PPRP review process, the adequacy of the study in fulfilling the SSHAC Level 3 process ofevaluation and integration, and the adequacy of documentation.

The closure letter from the SSC PPRP isprovided in Appendix B.The closure letter from the GMC PPRP, for the SWUS GMC SSHAC revision 1 report, which is thefoundation document for the PVNGS seismic hazard, is provided in Appendix C. Appendix C identifies PPRP reservations related "only to completeness of the documentation."

Appendix D provides the SWUS GMC Project letter "Transmittal of SWUS GMC SSHAC Level 3Technical Report (Rev. 2)." This letter documents that the final GMC Models used in the PVNGS hazardevaluation did not change with respect to the Revision 1 report.Appendix E reflects final PPRP endorsement of the SWUS GMC SSHAC revision 2 report, including resolution of all reservations identified in Appendix C PPRP closure letter for PVNGS.2.2.2 Summary of Seismic Source Characterization (SSC) ModelThis section summarizes the seismic source characterization (SSC) model developed for PVNGS (APS,2015). Regulatory Guide (RG) 1.208 (U.S.NRC, 2007) recommends performing seismological investigations within a radius of 320 km of the site (i.e., the Site Region).

The PVNGS SSC model regionexceeds this recommendation, extending to 400 km in order to include major faults in southern California and northwestern Mexico. The PVNGS SSC model comprises area earthquake sources and faultearthquake sources.

The area sources extend to 400 km from the PVNGS site (the "model region").

Ingeneral, the fault sources also are within 400 km of the PVNGS site, but some high slip-rate fault sourcesassociated with the main Pacific-North American plate boundary extend beyond 400 km from the site.Area sources are characterized with a defined geometry, seismogenic thickness, rate of earthquake occurrence, maximum earthquake magnitude (Mmax), and magnitude-frequency distribution function.

Inthe PVNGS SSC there are two alternative depictions of area sources, the Two-Zone and Seismotectonic models (Figures 2 and 3). Future earthquakes in the area sources are modeled with rupture characteristics such as location, dip, and slip sense. The recurrence of future earthquakes in each area source is treated asa truncated exponential distribution (Gutenberg-Richter) with spatially variable parameters based on thesmoothing of observed seismicity.

The smoothing approach used is the penalized maximum likelihood approach that was implemented by the CEUS-SSC Project (EPRI et al., 2012). Activity rates and b-valueswere calculated for area sources using assumptions on spatial smoothing of parameters and oninterpretations of historical earthquakes.

This process resulted in activity rates (for M>5) and b-values foreach 0.25 degree cell, for each area source used in the hazard calculations.

Fault sources are planar sources of earthquakes that are attributed to well-defined, seismogenic orpotentially seismogenic geologic faults or fault zones. The fault sources are characterized by their mappedlocation,

geometry, depth, slip sense, slip rate, magnitude, and magnitude-frequency distribution function.

The SSC model includes 168 fault sources (Figure 4). Hazard sensitivity analyses performed throughout the course of SSC model development and final hazard calculations indicate that a large number of thefault sources are not significant contributors to hazard at the site, because collectively 150 fault sourcescontribute less than 1% of the total reference rock fault hazard at 10 Hz and 1 Hz spectral frequencies.

Inkeeping with the hazard-informed approach for developing the SSC model prescribed by the SSHACprocess, this information was used to focus characterization efforts on those faults that matter most interms of hazard at the site.7 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3W NB3 NNFigure 2. The Two-Zone model for area sources in the PVNGS SSC model. The West and East sourcesmodel future earthquakes based solely on broad characteristics related to plate tectonic setting.

Black starindicates the location of the PVNGS site. Source: (APS, 2015).8 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3120" W 117" W 114" W III*"W 108* W36" N33o NFigure 3. The Seismotectonic model for area sources in the PVNGS SSC model. Sources includeSouthern Basin and Range (SBR), Southern California and Baja California (SCABA),

Gulf of California (GULF), Mexican Highlands (MH), Transition Zone (TZ), and Colorado Plateau (CP). Each sourcemodels future earthquakes based on variations in crustal behavior (interpreted from geophysical, seismological, and geological data) within each plate tectonic setting.

Black star indicates the location ofthe PVNGS site. Source: (APS, 2015).9 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3°NNW30 NFigure 4. Fault sources in the PVNGS SSC model. Black star indicates the location of the PVNGS site.Source: APS (2015).2.2.3 Summary of Ground Motion Characterization (GMC) ModelThis section summarizes the ground motion model developed by the Southwestern U.S. (SWUS) GroundMotion Characterization (GMC) Project (GeoPentech, 2015), and the modification of the Ground Motionlogic tree for use in the Probabilistic Seismic Hazard Analysis (PSHA) for PVNGS. The regional SWUSGMC Project developed site specific Ground Motion Prediction Equations (GMPEs) of the medianground motion and models of the standard deviation (sigma) for 5% damped pseudo-spectral acceleration.

These site specific GMPEs were developed for use in the Diablo Canyon Power Plant (DCPP) and PaloVerde Nuclear Generating Station (PVNGS) PSHAs. The site specific aspects of the GMPEs wereaddressed by optimizing the GMPEs for the seismic sources that have significant contributions to theseismic hazard at each site (GeoPentech, 2015).Two separate sets of GMPEs were developed by the SWUS GMC project for PVNGS. The first set ofGMPEs estimate ground motion for earthquakes in the less active area east of the highly active zoneassociated with the main plate boundary in California and Baja California (designated herein the "GreaterAZ" region, see the region labeled "east" in Figure 2). This set was optimized for predominantly normalfaulting earthquakes with M5 to 7, at distances less than 50 km. The second set of GMPEs estimateground motion for the distant, larger magnitude earthquakes in California and Mexico. This set of GMPEswas optimized for M7 to 8.5 earthquakes at large distances (greater than 200 km), and includes path-10 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3specific effects to capture the systematic differences in ground motion attenuation observed duringCalifornia and Mexico earthquakes at sites in central Arizona, as compared to sites in California.

Bothsets of GMPEs were developed for a reference site condition with shear wave velocities of 760 m/s andaverage kappa of 0.041 seconds (GeoPentech, 2015). To make the SWUS GMPEs applicable to PVNGSrock conditions, response spectrum adjustment factors that convert ground motions from the reference rock conditions to the rock conditions at PVNGS were applied to the hazard calculations.

See Section 2.3,Site Response Evaluation, for a further discussion of the response spectrum adjustment factors.2.2.3.1 GMPEs for the Greater AZ RegionFigure 5 shows the SWUS GMC logic tree for the median ground motion for both area sources and faultsin the Greater AZ region, which has the following three nodes: Distant Metric for Common Form, BaseModel, and Directivity.

One or more branches representing a single model (one-branch) or alternative models (multiple branches) were assigned to each node. The Distant Metric for the Common Form nodehad two branches.

These were the "RRuP based Common Form Model" branch, representing models thatwere based on closest distance from site to earthquake rupture (RRup) distance metric, and the "RjB basedCommon Form Model" branch, representing models that were based on the Joyner-Boore distance (RJB)metric. The GMC gave the "RRup based Common Form Model" branch a higher weight of 0.7 and the"RJB based Common Form Model" branch a lower weight of 0.3. Both models were applicable to strike-slip (SS), normal (NML), and reverse (REV) fault mechanisms.

Depending on the spectral period, theBase Model node had between 17 and 24 branches, with a non-uniform branch weight distribution.

Eachbranch represented a unique set of model coefficients that were applied to the RRup and RIB basedCommon Form Model. Only the Base Model branches downstream of the "RRup based Common FormModel" branch included coefficients that adjusted for hanging-wall effects.

The Base Model brancheswere labeled "Modell,"

"Model2,"

"Model3,"

etc. The Directivity node had a single branch, the "NO"branch, which had a branch weight of 1.0, showing that directivity effects were not assigned to theGMPEs.Figure 6 shows the SWUS GMC logic tree for the standard deviation in ground motion ("sigma")

modelfor sources of the Greater AZ region, which had the following three nodes: Model, Epistemic Uncertainty, and Aleatory Distribution Form. Each node had one or more branches.

The Model node had a singlebranch, "M-Dependent",

which had a branch weight of 1.0 showing that magnitude-dependent effectsinfluenced ground motion. The Epistemic Uncertainty node had three branches.

These were the "High","Central" and "Low" uncertainty

branches, which had branch weights of 0.3, 0.55, and 0.15, respectively.

The Aleatory Distribution Form node had two branches.

These were the "Mixture Model" and "Normal"form branches, which had branch weights of 0.8 and 0.2, respectively.

11 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Source ClaSS Distance Metric for ease Model -Assodation

%vdir one W1W branch isciTCommon FormI iimpl~ied tot &w~ based Common Form Models [ JModellAlModel A2'NL* based [=cACommon Form ..0.7 Model ANCoeffine nts and Period-de pervde nweights in FolderAN sources except 'PV"GSModeIACoefficientsW-in llegions alve I& I 09292014" ft., ba sed [ d lConmemo form0.3 Mdli1WXHW X+rights-HWXHWXX is one of the HW Modelbranclhves (I to 5)that goeswith the Model AN, as inColumn L of coefficient-filesinoCoeffice ntsand Period-de perident weights in Folder"PVN GSModel BCoetfclentsWeights-12122014*

Figure 5. Logic tree for the SWUS GMC median model for faults and area sources in the Greater AZregion. Modified after GeoPentech's (GeoPentech, 2015) Figure 2-1 in Appendix C (Part 1).I ModelEpisternk Uncertainty AlestoryDistibution FormHigh (95% percentie) 03M-Depondent Centml1.0 0.55Low (5% rcentile) 0.15Mixture ModelNormal0.2Figure 6. Logic tree for the SWUS GMC total sigma model for faults and area sources in the Greater AZregion. Modified after GeoPentech's (GeoPentech, 2015) Figure 4-1 in Appendix C (Part I).12 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 32.2.3.2 GMPEs for California and MexicoFigure 7 shows the SWUS GMC logic tree for the median ground motion model for faults and areasources in California and Mexico. This logic tree had the following five nodes: Median Model, Path Termapproach, Additional M scaling uncertainty, Median Path Term, and Directivity.

Each node had multiplebranches representing alternative models. The Median Model node had five equally weighted

branches, which were the Next Generation Attenuation-West 2 (NGA-W2)

GMPEs, namely the Abrahamson et al.(Abrahamson et al., 2014), Boore et al. (Boore et al., 2014), Campbell and Bozorgnia (Campbell andBozorgnia, 2014), Chiou and Youngs (Chiou and Youngs, 2014), and Idriss (Idriss, 2014) models. ThePath Term approach node had two branches, the "YES" and "NO" path term branches, which had branchweights of 0.8 and 0.2, respectively.

Three branches were assigned to the Additional M scalinguncertainty node, the "High," "Central,"

and "Low" uncertainty

branches, which had branch weights of0.2, 0.6, and 0.2, respectively.

The Median Path Term node was only applicable for the "YES" path termbranch and had three branches assigned to it. These were the "High," "Central,"

and "Low" uncertainty

branches, which were assigned branch weights of 0.2, 0.6, and 0.2, respectively.

Figure 8 shows the SWUS GMC logic tree for the sigma model for sources in California and Mexico.One sigma model was developed for the "YES" path term approach branch of the median GMPE, and thesecond sigma model was developed for the "NO" path term branch. The sigma model logic tree is similarto the Greater AZ source logic tree, and has the following three nodes: Model, Epistemic Uncertainty, andAleatory Distribution Form. The Model node has a single branch, "M-Dependent",

which has a branchweight of 1.0 showing that magnitude dependent effects were attributed to the uncertainty in the groundmotion. The Epistemic Uncertainty node has three branches.

These are the "High", "Central" and "Low"uncertainty

branches, with branch weights of 0.3, 0.55, and 0.15, respectively.

The Aleatory Distribution Form node has two branches.

These were the "Mixture Model" and "Normal" form branches, with branchweights of 0.8 and 0.2, respectively.

13 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3o"rCe Class 1 PadiTehm Add ion i M M e danalM O a cf l u n c a t a in vy P a lh T e m(95% pcenble) High {95% perceludme)

ASK14 0.2 0.20.2 Y ¥(S frm (enba IL...hCeI11E MSAU4 0S 0.6 0.60. Ia0oLow ;ý ,Low (5% percende)

S5% percetile

Iisklant, large M.1 0.2(A/Mexico source (B14 0.2 0NORegions 1, and 2& 31 0.2 1(Y14 2 igh0.2 0.2{95% percentile) 0no enral0.2Figure 7. Logic tree for the SWUS GMC median model for faults and area sources in California andMexico. Modified after GeoPentech's (GeoPentech, 2015) Figure 3-1 in Appendix C (Part I).Md l OitubuV ] F1Hfwn(95%

pereuile}

0.15tw(95%pereWe4 0.15Fromn No-Path Melia) Tee M4dependenl (en[2 NOinal055 0.2tow (5% petcenlile 0.15Figure 8. Logic tree for the SWUS GMC total sigma model for faults and area sources in California andMexico. Modified after GeoPentech's (GeoPentech, 2015) Figure 5-1 in Appendix C (Part I).14 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 32.2.3.3 GMPE Implementation Several simplifications to the ground motion logic trees were made in the hazard calculations for PVNGS.For earthquakes in the Greater AZ region, the Distance Metric for the Common Form logic tree node (seeFigure 5) was collapsed to the higher weighted RRUP based Common Form Model branch. A hazardsensitivity study for this logic tree node showed that collapsing the branches to a single branch wouldhave a minor impact on hazard (LCI, 2015a). For earthquakes in both the Greater AZ region and inCalifornia and Mexico, the Aleatory Distribution Form logic tree node (see Figures 6 and 8) wascollapsed to the higher weighted Mixture Model branch. A hazard sensitivity study showed thatcollapsing the branches to the Mixture Model is conservative (LCI, 2015a).Other important characteristics of the ground motion logic trees were modeled, such as the "YES/NO"path branches (see Figure 7) and the "High/Central/Low" epistemic uncertainty branches in the sigmamodel (see Figure 8).2.2.4 Summary of PSHA Implementation This section describes the probabilistic seismic hazard analysis (PSH-A) implementation of site specificrock seismic hazard at the PVNGS site. Primary inputs to this PSHA are the PVNGS SSC model (APS,2015) and the SWUS GMC model (GeoPentech, 2015).Response spectrum adjustment factors (AF) that convert ground motions from reference rock conditions (shear wave velocities of 760 m/s) of the SWUS GMPEs to the site specific rock conditions at PVNGSwere incorporated into the hazard calculations.

2.2.4.1 Methodology As described in Section 2.2.2, the PVNGS SSC includes area sources and fault sources.

There are twoalternative zonation models for area sources.

The first is the Two-Zone model, which includes the Westand East area sources (Figure 2). The PVNGS site is located within the East source, thus the East sourceis designated a "host" source (it includes the site location).

Second is the Seismotectonic model, whichincludes six area sources:

Southern California and Baja California (SCABA),

Gulf of California (GULF),Southern Basin and Range (SBR), Mexican Highlands (MH), Transition Zone (TZ), and Colorado Plateau(CP) (Figure 3). The PVNGS site is located within the SBR source, thus the SBR source is designated a"host" source.A total of 168 fault sources were included in the PVNGS SSC (Figure 4). Of these, 150 fault sources wereidentified as being insignificant to the overall hazard at the site, since they collectively contributed lessthan 1% to the total reference rock fault hazard at 10 Hz and 1 Hz spectral frequencies (LCI, 2015a). As aresult, these 150 faults were not considered in this analysis.

The remaining 18 faults that were included inthe soil hazard calculation are shown on Figure 9 and include the following:

• San Andreas Fault (SAF)* Cerro Prieto Fault (CP)* San Jacinto Fault (SJF)* Laguna Salada Fault (LS)* Elsinore Fault (ELF)* Agua Blanca Fault (AB)* Ballenas Transform Fault (BT)15 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Pinto Mountain Fault (PMNT)Calico-Hidalgo Fault (CH)Sand Tank Fault (ST)Big Chino Little Chino Fault (BCLC)Blue Cut Fault (BC)Pisgah-Bullion Mountain-Mesquite Lake Fault (PBMML)Horseshoe Fault (HS)Williamson Valley Grabens Fault (WVG)Carefree Fault (CF)Algodones Fault (AG)Plomosa East Fault (PE)120' W117"W114" W111 W108" W'NN43o* NFigure 9. Final 18 fault sources included in PVNGS hazard calculations.

Hazard insignificant faults(totaling 150) were excluded.

Black star indicates the location of the PVNGS site. Source: (APS, 2015).Two simplifications to the characterization of area seismic sources were made. The simplifications included (1) collapsing the rupture orientation branch to the central value, and (2) modeling fault dips asvertical.

For non-host

sources, these simplifications were not expected to have an impact on the hazard because ofthe large distances between the non-host area sources and the site (Figures 2 and 3). Non-host areasources were minor contributors to the total 10-4 hazard at 1 Hz spectral acceleration (SA). This16 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3insensitivity of hazard to rupture orientation and fault dip for non-host sources was confirmed byperforming a rupture orientation sensitivity using the SBR source (LCI, 2015a).Ground motion for host sources is sensitive to dip and crustal thickness because of the smaller distancebetween nearby ruptures and the site. The difference in ground motion between the SSC fault dips andseismogenic thicknesses, and a vertical dip and single crustal thickness, was taken into account in the hostsources by adjusting the ground motion for a vertical fault to the ground motion for a non-vertical faultwith multiple down-dip widths. The adjustment was calibrated to achieve accurate hazards at meanannual frequencies of exceedence (MAFEs) of 104 and 10-6 (LCI, 2015a).Ground motions were modeled for seven spectral frequencies (GeoPentech, 2015). The spectralfrequencies were peak ground acceleration (PGA; equivalent to 100 Hz SA), 20 Hz SA, 10 Hz SA, 5 HzSA, 2.5 Hz SA, 1 Hz SA, and 0.5 Hz SA. Seismic hazard was calculated for 20 ground motionamplitudes, which were 0.000001g, 0.0005g, 0.001g, 0.005g, 0.01g, 0.015g, 0.03g, 0.05g, 0.075g, 0.1g,0.15g, 0.3g, 0.5g, 0.75g, 1.0g, 1.5g, 3.0g, 5.0g, 7.5g and 10.0g. All ground motion equations represented spectral accelerations at 5% of critical damping; as such, spectral amplitude results presented in thisreport represent spectral acceleration at 5% of critical damping.2.2.5 Mean Site Specific Rock Hazard Curves for Major Contributing SourcesFigures 10 and 11 plot the mean site specific rock hazard for the PVNGS site for 10 Hz SA and 1 Hz SA.For both 10 Hz SA and I Hz SA, the area sources are the dominant contributors to hazard.10 Hz Site Specific Rock Hazard at Palo Verde, by Source Type1E-31E-4x-~-Mean1E-54"'Area1E_ "'FauftEl 1E-6___ -___1E-70.01 0.1 1 1010 Hz spectral acceleration (g)Figure 10. Site specific rock hazard curves showing total mean hazard and contributions from areasources and faults for 10 Hz SA. Note that the area source hazard and total mean hazard are almostidentical.

Source: Figure I from LCI (LCI, 2015c).17 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 31 Hz Site Specific Rock Hazard at Palo Verde, by Source Type1E-31E5 Mean--Areato--"6 Fault01E-70.01 0.1 1 101 Hz spectral acceleration (g)Figure 11. Site specific rock hazard curves showing total mean hazard and contributions from areasources and faults for I Hz SA. Source: Figure 2 from LCI (LCI, 2015c).For area sources there are the Two-Zone' and Seismotectonic 2 models, and for faults there are California-Mexico3 faults and Greater AZ4 faults. Figures 12 and 13 plot the seismic source contributions to the totalmean hazard from these groups for 10 Hz SA and 1 Hz SA. For 10 Hz SA, the Seismotectonic and Two-Zone models are the dominant contributors to hazard. For 1 Hz SA at 10-4 MAFE, the Seismotectonic andTwo-Zone models and California-Mexico faults are the dominant contributors to hazard; at 10-' MAFEand 10-6 MAFE, the Seismotectonic and Two-Zone models are the dominant contributors to hazard.Contributions from individual Seismotectonic and Two-Zone model sources for 10 Hz SA and 1 Hz SAare plotted in Figures 14 and 15. For both 10 Hz SA and 1 Hz SA, the Seismotectonic model, host sourceSBR is the dominant contributor to total area source hazard. Contributions from individual faults for 10Hz SA and 1 Hz SA are plotted in Figures 16 and 17. For both 10 Hz SA and 1 Hz SA, the San Andreas(SAF), Cerro Prieto (CP), and San Jacinto (SJF) faults are the primary fault contributors to total meanhazard.Figures 18 and 19 show the total mean hazard and sensitivity of 10 Hz SA and 1 Hz SA site specific rockhazard to the SWUS RRUp based Common Form Model ground motion equations used in the hazardcalculation from the Greater AZ faults and Greater AZ area sources5.The key identifies individual equations as Models 1 through 31 (this follows the naming convention of GeoPentech 2015, which uses adiscontinuous numbering system).

The spread in hazard curves at 10 Hz SA is fairly small with theexception of Model 19 and Model 23. Note that in the SWUS GMC model, individual GMPEs are'The Two-Zone model comprises the East and West area sources.2 The Seismotectonic model comprises the SCABA, GULF, CP, TZ, MH, and SBR area sources.' California-Mexico faults are the AG, SAF, CP, SJF, LS, ELF, AB, BT, PMNT, PBMML, BC, and CH faults.4 Greater AZ faults are the ST, BCLC, HS, WVG, CF, and PE faults.5 Greater AZ area sources are the East from the Two-Zone model, and the SBR, MH, TZ, and CP from theSeismotectonic model.18 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3determined independently from frequency to frequency, so a particular GMPE number in Figure 18 doesnot correspond to that same GMPE number in Figure 19. Direct comparisons of the hazard curvesbetween Figure 18 and 19 cannot be made because the GMPE numbers are not correlated.

10 Hz Site Specific Rock Hazard at Palo Verde, by Source Sub-Category1E-3S Mean1E-4-Selsmotectonic 0area1E-5 -Two-Zone areaC_. -Greater AZ faults'U1E-41E4- California-Mexico faults1E-70.01 0.1 1 1010 Hz spectral acceleration (g)Figure 12. Site specific rock hazard curves showing total mean hazardSeismotectonic and Two-Zone models, and from California-Mexico faults andHz SA. Source: Figure 3 from LCI (LCI, 2015c).and contributions fromGreater AZ faults for 101 Hz Site Specific Rock Hazard at Palo Verde, by Source Sub-Category1E-3* Mean:1E-4X .Selsmotectonic jarea1E-S -Two-Zone area*= -Greater AZ faults1E4 _Callfornla-Mexica 1E-7 faults1E-7,0.01 0.1 1 101 Hz spectral acceleration (g)Figure 13. Site specific rock hazard curves showing total mean hazard and contributions fromSeismotectonic and Two-Zone models, and from California-Mexico faults and Greater AZ faults for 1 HzSA. Source: Figure 4 from LCI (LCI, 2015c).19 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 310 Hz Site Specific Rock Hazard at Palo Verde, by Area Source1E-3a- -MeanC114 ____________sBR U -East1E-5 -GULFU'MH0* -West1E-6 _CP1E-70.01 0.1 1 1010 Hz spectral acceleration (g)Figure 14. Site specific rock hazard curves showing total mean hazard and contributions from individual sources of the Seismotectonic and Two-Zone models for 10 Hz SA. Source: Figure 5 from LCI (LCI,2015c).r1 Hz Site Specific Rock Hazard at Palo Verde, by Area Source1E-3.=1E41E-$1E-SSU -Mean~ 114 ~zz SSR--SBR-EastEU-GULF-MH-West_SCAR1E-70.01 1 10--r0.010.1I101 Hz spectral acceleration (g)Figure 15. Site specific rock hazard curves showing total mean hazard and contributions from individual sources of the Seismotectonic and Two-Zone models for 1 Hz SA. Source: Figure 6 from LCI (LCI,2015c).20 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 310 Hz Site Specific Rock Hazard at Palo Verde, by Fault-MeanSon Andreas1E-3 T_C1ES1E4-6C1E-S0.0Sen Jadato-Laguna Salade-EaIIm-SandTanic

-Pinto AIIH-PisabBig CthinCareFree10 H4adoWillamso0.1 110 Hz spectral acceleration (g)Figure 16. Site specific rock hazard curves showing total mean hazard and contributions from individual California-Mexico faults and Greater AZ faults for 10 Hz SA. Source: Figure 7 from LCI (LCI, 2015c).1 Hz Site Specific Rock Hazard at Palo Verde, by FaultIE-31ES1E-SC-Mean-Son AndreasSea Jacinto-Saendrank

-AgueBaenom

-PnsMntnMCareFree0 Horseshoe

-PlorosMONIS1E-70.010.111 Hz spectral acceleration (g)1Figure 17. Site specific rock hazard curves showing total mean hazard and contributions from individual California-Mexico faults and Greater AZ faults for 1 Hz SA. Source: Figure 8 from LCI (LCI, 2015c).21 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 310 Hz Site Specific Rock Hazard at Palo Verde, by SWUS CommonModel GMPE for Greater AZ Faults and Area Sources -MEAN-Model 11E-3 --hMcind-MoeMd147-Model 4-Model 7Modle 1S1E- Model 111E -Model 18Model 1UN~-Maodl 14I:: 154-Model is1E-5 Model 17Model isModel 13Model 20Model 22S1E-6 Model 23C Model 24Model 261E-7 model 270.01 0.1 1 10 Meoid2810 Hz spectral acceleration (g) M11d 30model 31Figure 18. Sensitivity to the SWUS Rup based Common Form model GMPEs from the Greater AZ faultsand area sources for 10 Hz SA. Hazard curves do not include weights on each alternative.

Source: Figure16 from LCI (LCI, 2015c).1 Hz Site Specific Rock Hazard at Palo Verde, by SWUS CommonModel GMPE for Greater AZ Faults and Area Sources --IE-3-Model41- Model aS-Model 104 -Model 1Model 14--Modlel 15-Model 171E-S -Me" iC-Model 19______ ______ _____M0de201E4Model 21IE-6 1m1d 24-Model 25Model 271E.7 Model 2n0.01 0.1 1 10 Moe 291 Hz spectral acceleration (g) Model 30Model 31Figure 19. Sensitivity to the SWUS Rup based Common Form model GMPEs from the Greater AZ faultsand area sources for 1 Hz SA. Hazard curves do not include weights on each alternative.

Source: Figure17 from LCI (LCI, 2015c).22 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Figure 20 shows the total mean hazard and sensitivity of 1 Hz SA site specific rock hazard to the SWUSNGA-W2 GMPEs (which were modified for path approach and magnitude-scaling uncertainty).

TheseGMPEs were used to calculate hazard from the California-Mexico faults and from area sources6 inCalifornia and Mexico. The key in Figure 20 identifies individual GMPEs as follows:

ASK isAbrahamson, Silva, and Kanai (Abrahamson et al., 2014), BSSA is Boore, Stewart, Seyhan, and Atkinson(Boore et al., 2014), CB is Campbell and Bozorgnia (Campbell and Bozorgnia, 2014), CY is Chiou andYoungs (Chiou and Youngs, 2014), and ID is Idriss (Idriss, 2014). At 1 Hz SA the ASK GMPE calculates the highest hazard and the ID GMPE calculates the lowest hazard. Figure 21 shows the total mean hazardand sensitivity of I Hz SA site specific rock hazard to the SWUS path approach modification to the NGA-W2 model ground motion equations used in the hazard calculations from the California-Mexico faults andarea sources.

For 1 Hz SA, the "YES" path approach gives a lower hazard than the "NO" path approachby a factor of 10 to 50.Figures 22 and 23 show the total mean hazard and sensitivity of 10 Hz SA and 1 Hz SA site specific rockhazard to the sigma model epistemic branches used in the hazard calculation from the Greater AZ faultsand area sources in the Greater AZ region. These figures show a moderate sensitivity to the sigma model.Figure 24 shows the total mean hazard and sensitivity of 1 Hz SA site specific rock hazard to the sigmamodel epistemic uncertainty branches used in the hazard calculation from the California-Mexico faultsand area sources.

This figure shows somewhat more sensitivity to the sigma model than Figure 23 showsfor the Greater AZ faults and area sources in the Greater AZ region. Taken together, Figures 20 through24 indicate that the sigma models "High" epistemic uncertainty branch produces the highest hazard.Figures 25 and 26 show the sensitivity of the SBR source hazard at 10 Hz SA and 1 Hz SA to maximummagnitude.

Figure 26 shows the 1 Hz SA SBR source hazard has a moderate sensitivity to the maximummagnitude.

These figures show that the SBR source hazard has a larger sensitivity to the maximummagnitude at the lower frequencies than at the higher frequencies.

Figures 27 through 32 show the deaggregation of hazard by magnitude and distance for spectralaccelerations corresponding to MAFEs of 104, 105, and 10-6. Plots for each MAFE show thedeaggregation of hazard for high (5 and 10 Hz SA) and low (1 and 2.5 Hz SA) spectral frequencies.

Forhigh frequencies, local small-magnitude earthquakes dominate at all MAFE levels. For low frequencies and a 10-4 MAFE, a bimodal distribution of local, small-magnitude earthquakes and distant, large-magnitude earthquakes are dominant contributors to seismic hazard. For low frequencies and a 10-5MAFE, local, large-magnitude earthquakes dominate.

The low frequency 10-6 MAFE hazarddeaggregation plot shows that moderate magnitude earthquakes at close distances dominate the hazard.Table I summarizes the mean magnitude and mean distance results from the deaggregation of hazard.Note that magnitudes indicated in Table I are on the moment magnitude scale.6 Area sources in California and Mexico are the West from the Two-Zone model, and SCABA, and GULF from theSeismotectonic model.23 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 31 Hz Site Specific Rock Hazard at Palo Verde, by SWUS GMPE Modelfor California-Mexico Faults and Area Sources1E-3-MEANa -ASKIE-5 _8SSAC-csM IE-6 -IIE-70.01 0.1 1 101 Hz spectral acceleration (g)Figure 20. Sensitivity to the SWUS NGA-W2 GMPEs path approach for California-Mexico faults andarea sources for 1 Hz SA. Hazard curves do not include weights on each alternative.

Source: Figure 18from LCI (LCI, 2015c).1 Hz Site Specific Rock Hazard at Palo Verde, by SWUS GMPE 'YES'and 'NO' Path Branches for California-Mexico Faults and AreaSources1E-3C"* 1E-4o -"MEAN1E-S -NoC10 -Yes-1E-6 -_______1E-70.01 0.1 1 101 Hz spectral acceleration (g)Figure 21. Sensitivity to the SWUS NGA-W2 modified for path approach for California-Mexico faultsand area sources in California and Mexico for 1 Hz SA. Hazard curves do not include weights on eachalternative.

Source: Figure 19 from LCI (LCI, 2015c).24 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 310 Hz Site Specific Rock Hazard at Palo Verde, by SWUS CommonModel GMPE Sigma for Greater AZ Fault and Area Sources1E-3CIE-41ESI. -MEAN9 -High" 1E-6 -CentralC -Low1E-70.01 0.1 1 1010 Hz spectral acceleration (g)Figure 22. Sensitivity to the epistemic uncertainty in sigma model for faults andGreater AZ region for 10 Hz SA. Hazard curves do not include weights on eachFigure 20 from LCI (LCI, 2015c).area sources in thealternative.

Source:1 Hz Site Specific Rock Hazard at Palo Verde, by SWUS CommonModel GMPE Sigma for Greater AZ Faults and Area SourcesIE-3C0~1E,4-MEAN1E-5 -High1O -Central1E6 "--_--Low CC1E-70.01 0.1 1 101 Hz spectral acceleration (g)Figure 23. Sensitivity to the epistemic uncertainty in sigma model from faults and area sources in theGreater AZ region for 1 Hz SA. Hazard curves do not include weights on each alternative.

Source: Figure21 from LCI (LCI, 2015c).25 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 31 Hz Site Specific Rock Hazard at Palo Verde, by SWUS GMPE Sigmafor California-Mexico Faults and Area Sources1E-31E-4S1E-5 -MEAN-HightO 1E4 -LOWC1E-70.01 0.1 1 101 Hz spectral acceleration (g)Figure 24. Sensitivity to the epistemic uncertainty in sigma model from California-Mexico faults andarea sources for 1 Hz SA. Hazard curves do not include weights on each alternative.

Source: Figure 22from LCI (LCI, 2015c).SBR 10 Hz Site Specific Rock Hazard at Palo Verde, by Maximum Magnitude 1E-3I 1E-4UM 7.9M 7.51 E-5 M 7.2* M 7.0114 M lAJ1E-70.01 0.1 1 1010 Hz spectral acceleration (g)Figure 25. Sensitivity to maximum magnitude for the SBR source for 10 Hz SA. Hazard curves do notinclude weights on each alternative.

Source: Figure 23 from LCI (LCI, 2015c).26 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3SBR 1 Hz Site Specific Rock Hazard at Palo Verde, by Maximum Magnitude 1E-3C1E-4-M 7.9M 7.-~1E-5 -M 7.2C IM 7.0-u s"II-M 6.8f 1E4-1E-70.01 0.1 1 101 Hz spectral acceleration (g)Figure 26. Sensitivity to maximum magnitude for the SBR source for I Hz SA. Hazard curves do notinclude weights on each alternative.

Source: Figure 24 from LCI (LCI, 2015c).Deaggregation of High Frequency 1E-4 hazard at Palo VerdeN00.120.10.080.060.04 .-n n20A5 ,. 25dw ~ 4W W5.7i-4"" 6.75-W'- 7.25_ 7'/ 7.755 1530Distance, km-'8.25Figure 27. Deaggregation of site specific rock hazard for 104 MAFE at spectral frequencies of 5 and 10Hz SA. Source: Figure 34 from LCI (LCI, 2015c).27 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Deaggregation of Low Frequency 1E-4 hazard at Palo Verde0.05 --'-0.04. ~ -- --~0.030.02 ------4v -6.255 15 3050 70 9071101301501 9 --7.75Dsac5170 90 60 .2itce, kr 20 2603 340 40oFigure 28. Deaggregation of site specific rock hazard for 10.4 MAFE at spectral frequencies of 1 and 2.5Hz SA. Source: Figure 35 from LCI (LCI, 2015c).Deaggregation of High Frequency 1E-5 hazard at Palo Verde0U0.16 .... ....0 .14 -, --0.120.10.080.04 6 *- -....,. -.0.06 -d~d AW 4W:;~0.02 d AN'4 _-- --5.25Ao -a 4 "- -_ 5.750 3 ,-, 6.255o 4o11 1o -40" 40" 6.7 " Y' 5150 So70 4--' AP4 ,W M 1 7.25 1- -8 65.7Distan 170190 2202- -- 8.25Ce, km 3 340400 3Figure 29. Deaggregation of site specific rock hazard for 10-5 MAFE at spectral frequencies of 5 and 10Hz SA. Source: Figure 36 from LCI (LCI, 2015c).28 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Deaggregation of Low Frequency 1E-5 hazard at Palo Verde0.14 ----------

0.12T-0.1 T-o 0.08 --o 0.06-C0.04 d0.02 PA,-0 0, __ 401 __ 5.25.... 6 o .25i 00 6.755 15 30 50 70 90 1 -.250110130 77Distanc k10 190 220 260 1-- 8.2590 220 20300 340 400Figure 30. Deaggregation of site specific rock hazard for 10-5 MAFE at spectral frequencies of I and 2.5Hz SA. Source: Figure 37 from LCI (LCI, 2015c).Deaggregation of High Frequency 1E-6 hazard at Palo Verde0.20.15 -I.C-25o 0 5 -. -u5 ,

4 / 720 AV 4W _ 5.7500 , 0. 6.25110 -' " 72550 70 90 11013 4W_ 2 7.71.,. 170 190 -rn r-..,. D iS ta n c e , k m 2 2 2 6 0 3 0 0 3 4 0 .0.n "'" 340 400 \Figure 31. Deaggregation of site specific rock hazard for 10.6 MAFE at spectral frequencies of 5 and 10Hz SA. Source: Figure 38 from LCI (LCI, 2015c).29 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Deaggregation of Low Frequency 1E-6 hazard at Palo VerdeN00U0.25 i--0.20.155-0.1-AW low~0.05 ..- --AW __ -- -5.25I _4W 01 Id AW .. " t p, 4,4.8 ' " 5.750 F4 -AOP A t , W " " 6.251530507::

-a *.. 4 APo- 70 zgo 1113 , __ -o' 9 ....., 7.. __/ .75 b,,oane, k2260 -Distance, 5"'190 300 -40'400 4Figure 32. Deaggregation of site specific rock hazard for 10-6 MAFE at spectral frequencies of I and 2.5Hz SA. Source: Figure 39 from LCI (LCI, 2015c).Table 1. Deaggregation results for MAFE 10-4,10-5, and 10-6 high and low frequencies.

MAFE 104MAFE 10-5MAFE 10-6Magnitude Distance(km)Magnitude Distance(kim)Magnitude Distance(km)High-Frequency 6.1 21 6.2 9 6.3 7Low-Frequency 7.4* 210* 7.6* 200* 6.8 9*M and R calculated for R > 100 km, because the contribution to hazard for R >of the total hazard (U.S.NRC, 2007). Source: Table 3 from LCI (LCI, 2015c).100 km is more than 5%30 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 32.2.6 Total Mean Seismic Site Specific Rock Hazard CurvesFigure 33 plots total mean hazard curves for the seven spectral frequencies at which hazard calculations were conducted.

The individual hazard curves are also documented in tabular form in Table 2.Site Specific Rock Hazard by Spectral Frequency at Palo Verde1E-3 -S1E-41ESU.M21E-64cx 5 HzI. -10Hz41E-5 2.5 HzS -20 Hz-5' Hz10 Hz2.5 Hz--20 Hi-PGA-1 Hz*0.5 Hz1E-71*0.010.1110Spectral acceleration (g)Figure 33. Total mean site specific rock hazard curves for seven spectral frequencies.

Source: Figure 25from LCI (LCI, 2015c).31 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table 2. Total mean site specific rock hazard for seven spectral frequencies.

Source: Table 2 from LCI(LCI, 2015c).Spectralacceleration g 0.5 Hz 1 Hz 2.5 Hz 5 Hz 10 Hz 20 Hz PGA0.000001 1.60E+00 1.60E+00 1.60E+00 1.60E+00 1.59E+00 1.59E+00 1.59E+000.0005 3.07E-01 5.90E-01 8.87E-01 7.16E-01 5.39E-01 5.12E-01 4.80E-010.001 1.74E-01 3.50E-01 5.52E-01 4.35E-01 3.12E-01 2.95E-01 2.59E-010.005 1.94E-02 5.61E-02 1.03E-01 7.51E-02 4.87E-02 4.80E-02 3.27E-020.01 4.58E-03 1.62E-02 3.44E-02 2.47E-02 1.62E-02 1.64E-02 9.47E-030.015 1.73E-03 6.84E-03 1.59E-02 1.18E-02 7.99E-03 8.12E-03 4.29E-030.03 2.77E-04 1.31E-03 3.61E-03 3.14E-03 2.34E-03 2.27E-03 1.07E-030.05 6.63E-05 3.55E-04 1.14E-03 1.18E-03 9.66E-04 8.75E-04 3.97E-040.075 2.11E-05 1.23E-04 4.61E-04 5.53E-04 4.87E-04 4.15E-04 1.84E-040.1 9.38E-06 5.84E-05 2.45E-04 3.25E-04 3.01E-04 2.47E-04 1.07E-040.15 2.94E-06 2.09E-05 1.02E-04 1.56E-04 1.52E-04 1.20E-04 5.00E-050.3 3.54E-07 3.69E-06 2.34E-05 4.39E-05 4.54E-05 3.44E-05 1.23E-050.5 6.30E-08 9.37E-07 7.45E-06 1.62E-05 1.70E-05 1.28E-05 3.70E-060.75 1.43E-08 2.81E-07 2.74E-06 6.70E-06 7.15E-06 5.36E-06 1.24E-06I 4.66E-09 1.11E-07 1.25E-06 3.35E-06 3.62E-06 2.73E-06 5.30E-071.5 8.68E- 10 2.72E-08 3.72E-07 1.13E-06 1.26E-06 9.65E-07 1.43E-073 3.60E- 11 1.87E-09 3.50E-08 1.29E-07 1.54E-07 1.25E-07 1.14E-085 2.61E-12 2.02E-10 4.86E-09 2.05E-08 2.64E-08 2.24E-08 1.39E-097.5 2.73E-13 2.92E-11 8.68E-10 4.14E-09 5.69E-09 5.05E-09 2.23E-1010 4.99E-14 6.71E-12 2.34E-10 1.22E-09 1.78E-09 1.64E-09 5.55E-112.3 Site Response Evaluation A site response analysis was performed for PVNGS following the guidance contained in SeismicEnclosure I of the 10 CFR 50.54(f) letter (U.S.NRC, 2012a) and in the Screening, Prioritization, andImplementation Details (SPID) (EPRI, 2013) for nuclear power plant sites that are not founded on hardrock (defined as 2.83 km/s).2.3.1 Description of Subsurface MaterialThe subsurface material at PVNGS consists of about 350 ft of basin sediments overlying

bedrock, with acrystalline basement complex at a depth of about 1,200 feet below the ground surface.

Basin sediments include stratigraphic subdivisions of sands, gravels, clays, silts, and fanglomerate.

Bedrock consists ofMiocene volcanic and interbedded sedimentary rocks. The basement complex comprises Precambrian granitic and metamorphic rocks (UFSAR, Rev. 17). In the following site response

analysis, thesematerials are divided into two representative site geologic

profiles, a shallow site profile and deep siteprofile, that are separated at the bottom of the basin sediments.

32 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 32.3.2 Development of Base Case Profiles and Nonlinear Material Properties Shallow Site Profile:

The PVNGS shallow site profile (LCI, 2015d) was developed from detailedlithologic descriptions and natural gamma logs from UFSAR and PSAR documents to define stratigraphic horizons of similar composition and texture.

Boring logs from beneath each of the three reactors areshown in Figure 34. A composite shallow stratigraphic profile (Figure 35) was created by averaging thethickness and properties of each correlative horizon.

Mean layer depths and their variability as well asbest-estimates of shear wave velocity (Vs) and unit weight are provided in Table 3. The control pointelevation for this profile is defined at the ground surface.Best-estimate values in Table 3 make up the base-case shallow site profile.

These Vs values wereestimated from suspension logs (LCI, 201Sf), downhole and crosshole surveys from the UFSAR andSpectral Analysis of Surface Waves (SASW) surveys (LCI, 2015g). Epistemic uncertainty (oYlv,) wasestimated for shear wave velocities in the base-case (BC) profile from the different measurements thatwere used to develop best-estimate values, and is provided for each layer in Table 3. Upper-range (UR)and lower-range (LR) profiles were developed by multiplying and dividing the BC profile byexp(1.28*01vs), following guidance in the SPID to achieve 10h and 90h percentile values. BC, LR, andUR Vs profiles are provided in Figure 36 and Table 4. Note that the UR profile does not include alithologic layer of fanglomerate to account for its possible non-existence.

33 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3DISTANCE BETWEEN BORINGS RELATIVE TO Ul-B1 (feel)0 1195 2390UI-B1 U2-BI U3-BI(elev. 963') (Olev. 956') (Olev. 960')950,900,850.,, 8M.. I0<w ILU V 202 750.I-Jw.1 UTHOLOGIC UNITS-700 .SANDCLAYZ M iM SANDIV I~ CLAY_j SANDLU 650 1oao VIII CLAYSANDX I FANGLOMERATE GENERALZED UTHILOGIC DESCRIPTIONS

-,I [I]I SAND: rand, illy clayey sand, or sandy sI550.. CLAY wit SAND: tamny clay or layey sand.410 410 X40 -CLAY: afy clay, sandy day. olmysy sit.FANGLOMERATE:

red brolao, hard, angtlar tooL-_ a.hdar. poorly aded slaitS in say sand matrix40 + SANDY TUFF and CLAY: -d to gray, -r.dely stratllad.

I NTERLAYERED FLOW BRECCIAS and FLO-S-gray. hard, moderalaly to highly fractured.

ANDESITE purple gray. hard, aphandtc, Figure 34. PVNGS Units 1, 2, and 3 generalized boring stratigraphy modified from Units 1, 2, and 3 B 1borings PSAR, Amendment

20. Lithologic units are identified with Roman numerals I-X. Source: Figure2 from LCI (LCI, 2015d).34 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Uthologic Description I -SAND. yellow to red to brown. sand with thin irregular bedsof silt, clayey-sift, and silty-clay Depth(f)0(It msl)953-940Unit contact(dapthelev) 920S900 51/901-880860M.840II -CLAY. yellow to red to brown, clayey-silt and silty-clay withlenses of fine-grained sand and silty-sand

-820.800159/794166/786780186/767.760205/748.740720 230/723 "J237/715LW700 0Ir.680 >*660--0.660 -III -SAND: brown, sandy-silt.

silty sand, and sandy-clay IV -CLAY: brown, silty-clay, clayey-silt, low to medr plasticity, noncalcareous to slightly calcareous, very stiff to hardV -SAND: brown to red-brown silty-sand, sandy-silt, and clayeysand, very stiff to hard, nonplastic to low plasticity paraconformity VI -CLAY: yellow to red-brown, silty-clay, very stiff to hard, distinctupper contact, slightly to highly calcareous, med. to high plasticity VII -SAND: sandy-silt and silty sand, brown, non-plastic VIII -CLAY: yellow to red-brown, silty-clay, clayey-silt.

sandy-silt, silty-sand,sandy-clay, clayey-sand, calcareous, very stiff to hard,high plasticity311/642620600580IX -SAND: brown to red-brown, sand, silty-sand, and clayey-sand, occasional gravel clasts, subangular to subrounded, dense to verydense, very stiff to hard341/612unconformity X -FANGLOMERATE:

brown to gray, moderately to well cementedvolcanic clasts derived from underlying bedrock in a matrix of sand,silt and occasionally tuffaoeous sand, elevation of upper contactand thickness of unit vary across the site560 395/558major unconformity GENERALIZED LITHOLOGY SandClayB Fanglorerate I LrrHOLOGIC UNITXl -BEDROCK.

see deep profile figureFigure 35. Shallow site stratigraphic column for the PVNGS site. Source: Figure 5 from LCI (LCI,2015d).35 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Vs (tt/sec)200001000300040000-LR-BC-UR100150t_)2002A0300350400450Figure 36. Shallow shear wave velocity profiles for PVNGS: base-case (BC), lower-range (LR), andupper-range (UR). Note that the UR profile ends at a depth of 340 ft. Source: Figure 32 from LCI (LCI,2015d).36 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table 3. Dynamic properties of shallow site prfile. Source: Table 9 from LCI (LCI, 2015d)Strati- Unit Sigma BaseSrt- Generalized Depth Thickness Unt SgaCase sigma sigmaLayer graphic lithlzed (Dt) (it) Weight Depth Vs Vs Vs (In)Unit (pce) (0t) (Vt/s) (in) [SPID]1 I Sand 0 21 120 0.0 1017 0.070 0.232 I Sand 21 14 120 3.2 1041 0.088 0.193 1 Sand 35 10 120 5.4 1150 0.075 0.174 I Sand 45 7 120 6.9 1181 0.063 0.155 II Clay 52 60 125' 8.0 1208 0.087 0.156 II Clay 112 25 125' 3.5 1293 0.073 0.157 II Clay 137 22 125' 4.3 1391 0.073 0.158 III Sand 159 8 126' 5.0 1432 0.055 0.159 IV Clay 167 19 125' 8.0 1446 0.049 0.1510 V Sand 186 19 1262 2.0 1459 0.050 0.1511 VI Clay 205 5 125' 5.0 1510 0.103 0.1512 VI Clay 210 20 125' 1.8 1742 0.145 0.1513 VII Sand 230 8 1262 2.0 1829 0.160 0.1514 VIII Clay 238 52 125' 1.0 2094 0.127 0.1515 VIII Clay 290 21 125' 15.9 2094 0.127 0.1516 IX Sand 311 30 130 17.0 2094 0.127 0.1517 X Fanglomerate 341 86 140 60.0 3262 0.176 0.15Bed- Andesite/

XI basalt/flow 427 N/A3 140 83 4485 N/A3 N/A3breccia/tuff Notes:1125 pcf is the average unit weight of all clay units. The unit weights for all clay units are averaged for thesake of simplicity in the site response analysis.

2126 pcf is the average unit weight of Sand Units III, V, and VII. The average is used for the sake ofsimplicity in the site response analysis.

3In the site response analysis for shallow profile, Unit XI is considered as the half space.37 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table 4. Layer depths, thicknesses, and shear wave velocities (Vs) for lower-range (LR), base-case (BC),and upper-range (UR) profiles for the shallow site profile at PVNGS. Source: Table 10 from LCI (LCI,2015d).Depth Thickness Vs (ft/sec)__

Layer (ft) (fi) LR BC UR1 0 21 929 1017 11132 21 15 930 1041 11653 35 10 1046 1150 12664 45 7 1090 1181 12805 52 60 1081 1208 13516 112 25 1178 1293 14197 137 22 1266 1391 15288 159 8 1334 1432 15369 167 19 1359 1446 154010 186 19 1369 1459 155511 205 5 1324 1510 172312 210 20 1448 1742 209813 230 8 1489 1829 224514 238 52 1780 2094 246215 290 21 1560 2094 246216 311 30 1560 2094 246217 341 86 2603 3262 N/A38 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Deep Site Profile:

The PVNGS deep site profile was developed in LCI Calculation Adjustment Factorsfrom Reference Rock to Palo Verde Rock (LCI, 2015b) and LCI (LCI, 2015d) from data presented in theUFSAR and Geological Society of America Bulletin A seismic-refraction survey of crustal structure incentral Arizona (Warren, 1969) to model the bedrock and basement complex materials.

There are noborings underneath the three units that reach the top of the basement

complex, so the upper contact isestimated using a geologic cross-section from the UFSAR that shows the shallow and deep stratigraphy atthe site (Figure 37). Mean layer depths and their variability as well as best-estimates of Vs and unitweight are provided in Table 5. The control point elevation for this profile is defined at the bottom of theshallow site profile.Best-estimate values in Table 5 make up the base-case deep site profile.

These Vs values were estimated from suspension (LCI, 2015f) for bedrock.

Vs for the basement complex was determined using typicalseismic wave velocities for granodiorite due to the absence of site specific data. Epistemic uncertainty was estimated for Vs in the BC profile using a logarithmic standard deviation of 0.35 as recommended bythe SPID (EPRI, 2013).Just like the shallow site profile, UR and LR Vs values were developed by multiplying and dividing theBC profile value by exp(1.28*OInVs),

respectively.

Uncertainty in the thickness of each layer wasaccounted for in the LR and UR deep site profiles.

For the volcanics, this uncertainty was determined from boring logs as described in LCI (LCI, 2015d). For the upper basement layers, this uncertainty wastaken as 10 percent of each respective mean thickness.

The LR and UR profiles were constructed bypairing 90th percentile Vs with 10th percentile thickness (and vice versa) in order to maximize thevariation in travel time, in a manner similar to what is done in EPRI (EPRI, 2013). The three resulting Vsprofiles are shown in Figure 38 and Table 6.' 10 R T 4iKA A'.0.1eli-ia-13U!ThO!,OGIC DESCRIPTIONI A

~~ UIJ C tL (P ,e lAPS INfl1,eliT t :B..E N O UILEFigure 37. Geologic cross-section showing the shallow and deep stratigraphy at the PVNGS site;modified from UFSAR Figure 2.4-27. The map in plan view on the right shows the cross-section line, asnoted by A-A'; map is modified from PSAR Figure 2.5-13. Note that Units 1-3 are west of the cross-section line, between borings PV-21 and PV-24. Source: Figure 8 from LCI (LCI, 2015d).39 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table 5. Dynamic properties of deep site profile.

Source: Table 16 from LCI (LCI, 2015d).Depth Unit Mean Mean Vs Poisson's Elevation Mean Sigma,Strat. Generalized to top weight Vs Vp Sigma Ratio Thickness Thickness unit lithology of layer(ft) (pcf) (ft/sec)

(ft/sec)

(In) Mean, Top Sigma, Range +, Range -,(ft msl) Top 3 Top Top (ft) (ft)(___msl)_Top_(ft)___(ft msl) (ft msl)Andesite/

XI basalt/flow 395 140 4485 9863 0.35 0.370 558 83 641 475 808 145breccia/

tuffWeathered XII granodiorite/

1203 146' 5438 10786 0.35 0.330 -250 N/A N/A N/A 20 10meta-granite (top)Weathered XII granodiorite/

1223 152' 7343 12632 0.35 0.245 -270 N/A N/A N/A 20 10meta-granite (middle)Weathered XII granodiorite/

1243 157' 9248 14477 0.35 0.155 -290 N/A N/A N/A 20 10meta-granite (bottom)XI Granodiorite/

1263 1712 10200 15400 0.35 0.109 -310 N/A N/A N/A N/A N/Ameta-granite Notes:1Unit weight for the weathered basement complex is determined from Vp.2 Unit weight for unweathered basement complex is determined from Warren (Warren, 1969).3 Sigma top is only calculated for Andesite XI for use in shallow site profile site response calculations.

Sigma is calculated usingtop elevation contact of bedrock from Units 1-3 B 1 boreholes (Figure 34).40 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Vs (m/s)0 1000 20003000400005000010000.2 15000E0""* 200025003000Figure 38. Deep shear wave velocity profiles for PVNGS. A depth of 0 corresponds to the bottom of theshallow profile (soils).

Also shown are the Warren (Warren, 1969) and SWUS GMC (GeoPentech, 2015)profiles.

Source: Figure 1 from LCI (LCI, 2015b).41 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table 6. Lower-range (LR), base-case (BC), and upper-range (UR) profiles for the deep site profile atPVNGS. Source: LCI (LCI, 2015d).Lower Range Profile (low velocities, thicker layers, base-case density);

weight = 0.3Description Thickness (m) Vs (m/s)Volcanic bedrock sequence 324.2 873.4Basement (shallow; weathered top) 10.0 1,059.0Basement (shallow; weathered middle) 10.0 1,430.0Basement (shallow; weathered bottom) 10.0 1,800.9Basement (shallow) 1,784.2 1,986.3Basement (deep) 22,560.0 3,680.0Base Case Profile (median Values all parameters);

weight = 0.4Description Thickness (m) Vs (m/s)Volcanic bedrock sequence 267.6 1,367.0Basement (shallow; weathered top) 6.1 1,657.5Basement (shallow; weathered middle) 6.1 2,238.1Basement (shallow; weathered bottom) 6.1 2,818.8Basement (shallow) 1,581.7 3,109.0Basement (deep) 20,000.0 3,680.0Upper Range Profile (high velocities, thinner layers, base case density);

weight = 0.3Description Thickness (m) Vs (m/s)Volcanic bedrock sequence 211.0 2,139.6Basement (shallow; weathered top) 2.2 2,594.3Basement (shallow; weathered middle) 2.2 3,503.1Basement (shallow; weathered bottom) 2.2 3,680.0Basement (shallow) 1,379.3 3,680.0Basement (deep) 17,440.0 3,680.02.3.2.1 Shear Modulus and Damping CurvesSite specific nonlinear dynamic material properties were not available for PVNGS for the soils and firmrock that comprise the shallow site profile.

The soil material over the shallow site profile was modeledwith both the EPRI cohesionless soil (EPRI, 1993) and Peninsular Range (Silva et al., 1996) G/Gmax andhysteretic damping curves while the clay material was modeled using Vucetic and Dobry (Vucetic andDobry, 1991) values. Consistent with the SPID (EPRI, 2013), the EPRI soil and Peninsular Range curveswere considered to be equally appropriate to represent the more nonlinear response likely to occur in thematerials at this site. Only Vucetic and Dobry (Vucetic and Dobry, 1991) curves were used to model thenonlinear response of the clay layers. The generic degradation curves of Vucetic and Dobry (Vucetic andDobry, 1991) were developed with a wide range of clay data and are judged to be the best equivalent-42 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3linear material model available.

Table 7 summarizes the alternative material properties applied to eachlayer.Table 7. Degradation curves for each stratigraphic unit at PVNGS. Source: Table 14 from LCI (LCI2015d)._____

Degradation Degradation Layer Stratigraphic Generalized Depth Thickness Curves CurvesUnit lithology (ft) (ft) (Alternative

1) (Alternative 2)EPRI Soil Peninsular Curves1 I Sand 0 210-ft-St 0-20 ft 0-50 ftEPRI Soil Peninsular Curves2 1 Sand 21 14 2-0f -0f20-50 ft 0-50 ftEPRI Soil Peninsular Curves3 1 Sand 35 10200ft-St 20-50 ft 0-50 ftEPRI Soil Peninsular Curves4 1 Sand 45 7 2-~t0Sf20-50 ft 0-50 ftVucetic and Dobry Vucetic and Dobry(1991)-PI=30 (1991)-PI=30 Vucetic and Dobry Vucetic and Dobry(1991)-PI=30 (1991)-PI=30 Vucetic and Dobry Vucetic and Dobry(1991)-PI=30 (1991)-PI=30 EPRI Soil Peninsular Curves120-250 ft 51-500 ftVucetic and Dobry Vucetic and Dobry(1991)-PI=30 (1991)-PI=30 EPRI Soil Peninsular Curves120-250 ft 51-500 ftVucetic and Dobry Vucetic and Dobry(1991)-PI=30 (1991)-PI=30 Vucetic and Dobry Vucetic and Dobry(1991)-PI=30 (1991)-PI=30 EPRI Soil Peninsular Curves13 VII Sand 230 8 1020f 150f120-250 ft 51-500 ftVucetic and Dobry Vucetic and Dobry(1991)-PI=30 (1991)-PI=30 Vucetic and Dobry Vucetic and Dobry(1991)-PI=30 (1991)-PI=30 EPRI Soil Peninsular Curves16 IX Sand 311 30 20S~t5-Of 250-500 ft 51-500 ftEPRI Soil Peninsular Curves17 X Fanglomerate 341 86ft43 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Shear modulus and damping curves were not required for the deep site profile.

Strains will remain low insuch firm materials at the depths represented by this profile, so it is not necessary to model nonlinear behavior.

2.3.2.2 KappaAdjustment factors were developed in LCI (LCI, 2015b) to convert ground motions from the reference rock associated with the GMPEs from the SWUS GMC (GeoPentech, 2015) to site specific rockconditions at PVNGS corresponding to the deep site profile described above. These Vs-kappa7adjustments consist of two parts. The first part accounts for impedance differences.

This part can becalculated using the Quarter-wavelength approach (Boore and Joyner, 1997; Boore, 2003, 2013) andaffects all frequencies.

The second part accounts for the differences in kappa. It has an exponential formand affects mainly the high frequencies.

The net adjustment factor (in Fourier-amplitude space) is theratio of the target filter (for site specific rock) divided by the host filter (for reference rock). Multiplevalues of this factor were calculated to account for uncertainty in the inputs.The host kappa value for SWUS GMPEs was taken as 0.041 sec (GeoPentech, 2015), and the target kappavalue at PVNGS was taken as 0.033 sec with a logarithmic standard deviation of 0.5 (GeoPentech, 2015).The BC target kappa value is 0.033 sec, and the associated uncertainty was used to derive the I0th and 90'hpercentiles for a LR and UR value, respectively.

The BC, LR, and UR target kappas were combined witheach of the BC, LR, and UR deep site profiles in LCI (LCI, 2015d) to get nine sets of adjustment factors(Table A-I in Appendix A and Figure 39). The weights applied to the {BC, LR, UR} kappa alternatives and {BC, LR, UR} Vs profile alternatives were each {0.4, 0.3, 0.3}, respectively.

The resulting combinedweights for the nine sets of adjustment factors are provided in Table A-I in Appendix A.7 Vs is the shear wave velocity; kappa is a quantity that represents the anelastic attenuation in the upper crust. In thenomenclature of Anderson and Hough (Anderson and Hough, 1984), the kappa used in this calculation corresponds to kappa-zero, as it captures attenuation effects in the upper crust, rather than whole-path attenuation.

44 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 310A-0EIM10.10.11 10Frequency (Hz)100-LB Profile, LB kappa (0.09)-LB Profile, UIB kappa (0.09)-Median Profile, Median kappa (0.16)-UB Profile, LB kappa (0.09)-LB Profile, Median kappa (0.12)-Median Profile, LB kappa (0.12)-Median Profile, UB kappa (0.12)--UB Profile, Median kappa (0.12)'--UB Profile, UB kappa (0.09)Figure 39. Adjustment factors to convert ground motions from SWUS reference rock to PVNGS rockconditions.

Although some of these adjustment factors become very large at high frequencies (as a resultof the kappa adjustments),

the SWUS GMC (GeoPentech, 2015) rock motions have zero or no energy atthese frequencies (say, above 20 Hz). Therefore, the effect on spectral accelerations is expected to bemuch smaller than the effect shown here. Source: Figure 2 from LCI (LCI, 2015b).45 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 32.3.3 Randomization of Shear Wave Velocity ProfilesRandomization of each profile (BC, LR, UR) was performed to account for aleatory variability of theassigned properties across the site at the scale of a typical nuclear facility.

The following properties wererandomized:

" Shear wave velocity in each layer. SPID (EPRI, 2013) guidance was followed.

Aleatoryvariability of shear wave velocities (Vs) in each layer was modeled in a depth-dependent mannerusing the logarithmic standard deviations provided in Table 3. For all layers, shear wavevelocities were truncated to +/-2 a,,vs. Correlation of Vs between adjacent layers was alsomodeled according to Toro (Toro, 1995) using USGS site class "A" parameters (which are forhard rock). Note that the depth used to determine variability and correlation corresponds to themiddle of each layer.* Material properties.

SPID guidance was followed.

Realizations were truncated at +/-2 a,. for bothG/Gmax and damping curves." Profile layer depths and thicknesses.

Depth to the top of each layer was modeled using a Normaldistribution.

The mean and standard deviation used for this model were the values provided inTable 3. Each realization of depth to the top of a given layer was limited to +/-2o.* Depth to bedrock.

Depth to the bedrock was modeled using a Normal distribution.

The mean andstandard deviation used for this model were the values provided in Table 3. Each realization ofdepth to the top of bedrock was limited to +/-2(y." Kappa. Kappa was modified per Section 2.3.2.2 to adjust SWUS GMPEs to site specific PVNGSrock conditions.

Sixty random velocity profiles were generated for each combination of profile (BC, LR, and UR),material model (EPRI or Peninsular values),

input spectrum (Refer to Section 2.3.4), and set ofadjustment factors (Refer to Section 2.3.2.2).

2.3.4 Input SpectraInput control motions were obtained using previously calculated reference-rock hazard for PVNGS (LCI,2105a). Both the high-frequency (HF; derived from hazard at 5 Hz and 10 Hz spectral frequencies) andlow-frequency (LF; derived from hazard at 1 Hz and 2.5 Hz spectral frequencies) spectra from LCI (LCI,2015a) at mean annual frequencies of exceedence (MAFEs) of 10-4, 10-5, and 10-6 were scaled to 11different PGA amplitudes between 0.01 g and 1.5 g (for a total of 22 input control motions) following guidance from the SPID. The 11 PGA amplitudes are approximately equally spaced (logarithmically) within that range. The HF or LF spectrum with the nearest PGA value to each amplitude was scaled tothat amplitude.

The resulting scaled HF motions are provided in Table A-2 of Appendix A, and scaled LFmotions are provided in Table A-3 of Appendix A.Input response spectra were converted to Fourier amplitude spectra (FAS) using inverse random vibration theory (IRVT; e.g., Rathje et al., 2005). IRVT requires an estimate of ground motion duration for eachinput control motion, which was calculated according to the method in Rathje et al. (2005). This durationcalculation requires mean deaggregated magnitudes (M) and distances (R) for each HF and LF spectrum(from LCI, 2015a and provided in Table 8) as well as stress drop and crustal velocity values. Values forstress-drop (100 bars) and crustal velocity (3,500 m/s) for the PVNGS region were obtained from generalwestern United States values provided in Al Atik et al. (Al Atik et al., 2014). The calculated durations arelisted in Table 8.46 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Figure 40 shows the IRVT-derived FAS corresponding to the HF input response spectrum at a MAFE of10-4 before and after the host kappa value was enforced.

Removal of the high frequency content from theFAS by enforcing kappa results in an IRVT-derived response spectrum slightly different from the inputtarget spectrum, however this deviation is not expected to have a significant effect on site responsecalculations.

Kappa was enforced at about 10 Hz where the slope of the FAS obtained from the IRVTprocess is very close to the host kappa value. These results are representative of the other input controlmotions.Table 8. Deaggregated magnitudes and distances for reference rock and associated durations.

Source:LCI (LCI, 2015a).Motion Magnitude (Mw) Distance (km) Duration (sec)10-4 Low Freg. 7.5 210 26.3104 High Freg. 6.1 18 4.0610-5 Low Freg. 7.6 200 27.710-5 High Freq. 6.2 8.0 3.9410-6 Low Freg. 6.8 8.0 7.4610-6 High Freq. 6.4 6.0 4.7647 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 310.1!0 IZ!k)&L0 10 20 30 40 50Frequency,

[Hz]-Tare kI1MA speck-mW--rV -pch10o 101Frequency.

(Hz]it10V1o~t(0'CIL .~10-T-rg01 ku peck-m---w spck20 30Frequency,

[Hz]10? 10,Frequency.

1Hz]10Figure 40. IRVT-derived FAS and its corresponding RVT-derived response spectrum for the 104 hazardlevel HF input control motion before (top figures) and after (bottom figures) host-kappa value of 0.041sec is enforced.

Source: Figure 43 from LCI (LCI, 2015d).2.3.5 Methodology A random vibration theory (RVT) approach was employed to perform the site response analyses for thePVNGS site. This process utilizes a simple, efficient approach for computing site specific amplification functions and is consistent with SPID (EPRI, 2013) guidance.

For the BC, LR, and UR shallow siteprofiles, site amplification factors (SAF) are developed for seven spectral frequencies (0.5 Hz SA, 1.0 HzSA, 2.5 Hz SA, 5.0 Hz SA, 10 Hz SA, 20 Hz SA, and 100 Hz SA or PGA) over the range of spectralamplitudes represented by the input control motions (refer to Section 2.3.4). Each set of SAF incorporates the various types of variability in profile and material properties described above, as well as uncertainty inkappa and deep shear wave velocities as represented by the nine sets of adjustment factors in Fourier48 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3amplitude space. To include the deep site profile effect on SAF, the IRVT-derived input FAS wasmultiplied by the set of Vs-kappa adjustment factors from Section 2.3.2.2 prior to using that inputspectrum to drive the shallow site profile.2.3.6 Amplification Functions The results of the site response analysis consist of SAF for 5% damped pseudo-absolute response spectrathat describe the amplification (or de-amplification) of reference rock motion as a function of frequency and input reference rock amplitude.

The amplification factors are represented in terms of a medianamplification value and an associated log standard deviation for each oscillator frequency and input rockamplitude.

A minimum median amplification value of 0.5 was employed in the present analysis, consistent with SPID guidance (EPRI, 2013). Figures 41a through 41f illustrate (using the BC velocityprofile) the median and +/- 1 standard deviation in the predicted surface spectra and amplification factorsdeveloped for the HF and LF loading levels corresponding to MAFEs of 104, 105, and 10-6 parameterized by reference rock spectral amplitudes (0.01g to 1.50g) for the BC and EPRI soil G/Gmax and hysteretic damping curves. The variability in the amplification factors results from variability in shear wavevelocity, depth to hard rock, modulus reduction curves, hysteretic damping curves, and application of thenine Fourier adjustment functions to account for uncertainty in kappa and the deep site Vs profile.

Toillustrate the effects of nonlinearity at PVNGS, Figures 42a through 42c show the final amplification factors developed with all combinations of the varied parameters for each of the three profiles (base-case, lower-range, and upper-range).

Note that all required weighted combinations of the resulting SAF wereperformed in linear (SAF) space as opposed to log (In[SAF])

space.Figures 42a through 42c show differences at all loading levels and frequencies.

Values of median SAFand their variability at spectral frequencies of 0.5 Hz SA, 1.0 Hz SA, 2.5 Hz SA, 5.0 Hz SA, 10 Hz SA,20 Hz SA, and PGA over a range of amplitudes are provided in Appendix A Tables A-4, A-5, and A-6 forthe BC, LR, and UR velocity profiles.

49 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 310'*10102107-10110010* 101 102 10-1 10o 101Frequency,

[Hz] Frequency,

[Hz]102Figure 41a. PVNGS BC surface response spectra and SAF for 104 HF input motion using the EPRI soilmaterial model and a single reference rock to local rock adjustment function.

Green lines are spectra for60 individual randomized profiles.

Median (black solid line) and +/-Ial, (black dashed lines) are alsoshown. Source: Figure 46 from LCI (LCI, 2015d).101 10110o10,0 101 102 101 10 10 102Frequency,

[Hz] Frequency,

[Hz]Figure 41b. PVNGS BC surface response spectra and SAF for 10-4 LF input motion using the EPRI soilmaterial model, and a single reference rock to local rock adjustment function.

Green lines are spectra for60 individual randomized profiles.

Median (black solid line) and +la11, (black dashed lines) are alsoshown. Source: Figure 47 from LCI (LCI, 2015d).50 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3101101107I10-100lo-t106 10, 10, 10" 10" 10,Frequency,

[Hz] Frequency,

[Hz]102Figure 41c. PVNGS BC surface response spectra and SAF for 10-5 HF input motion using the EPRI soilmaterial model and a single reference rock to local rock adjustment function.

Green lines are spectra for60 individual randomized profiles.

Median (black solid line) and +/-+lon, (black dashed lines) are alsoshown. Source: Figure 48 from LCI (LCI, 2015d).101 10'*1CoI100v10 10o 101 10,Frequency,

[Hz]100 101Frequency.

[Hz]102Figure 41d. PVNGS BC surface response spectra and SAF for 10-5 LF input motion using the EPRI soilmaterial model, and a single reference rock to local rock adjustment function.

Green lines are spectra for60 individual randomized profiles.

Median (black solid line) and +1an (black dashed lines) are alsoshown. Source: Figure 49 from LCI (LCI, 2015d).51 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3101101I 107'100103107,106 10 10 10 10° 10,Frequency,

[Hz] Frequency,

[Hz]102Figure 41e. PVNGS BC surface response spectra and SAF for 10-6 HF input motion using the EPRI soilmaterial model and a single reference rock to local rock adjustment function.

Green lines are spectra for60 individual randomized profiles.

Median (black solid line) and +/-+al, (black dashed lines) are alsoshown. Source: Figure 50 from LCI (LCI, 2015d).101 1011070 ,CO110 .210- i0, 101 102 1071 100 101 102Frequency,

[Hz] Frequency,

[Hz]Figure 41E. PVNGS BC surface response spectra and SAF for 10-6 LF input motion using the EPRI soilmaterial model, and a single reference rock to local rock adjustment function.

Green lines are spectra for60 individual randomized profiles.

Median (black solid line) and +/-101n (black dashed lines) are alsoshown. Source: Figure 51 from LCI (LCI, 2015d).52 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 33.532.5L.% 2C* 1.50.5-4-PGA-M-20 Hz' 10 Hz-M-5 Hz-,--2.5 Hz-4-1 Hz--0.5 Hz0 4-0.0010.01 0.1 1Spectral acceleration, (g)100.60.50.4O.4°U0.3M00.200.1--PGA-M-20 Hz-*-10 Hz-)4-5 Hz--- 2.5 Hz--@-1 Hz--0.5 Hz0 4-0.0010.01 0.1 110Spectral acceleration, (g)Figure 42a. PVNGS BC profile median amplification factors and log standard deviation as a function ofspectral acceleration.

Source: Figure 55 from LCI (LCI, 2015d).53 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 33.532.5U-S21.510.5-4--PGA-3-20 Hz-*10 Hz-(-X5 Hz-0-2.5 Hz-0-1 Hz-60.5 Hz00.0010.010.1110Spectral acceleration, (g)0.60.5U.C 0.4".04-0.30-j0.1----PGA-"-20 Hz-10 Hz-06-5 Hz----2.5 Hz--1 Hz-+0.5 Hz0 -0.0010.01 0.1 1Spectral acceleration, (g)10Figure 42b. PVNGS LR profile median amplification factors and log standard deviation as a function ofspectral acceleration.

Source: Figure 56 from LCI (LCI, 2015d).54 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 33.532.5U-21.50.5-4--PGA-3-20 Hz' 10 Hz-0-5 Hz-)--2.5 Hz-@-1 Hz--0.5 Hz0 4-0.0010.01 0.1 1Spectral acceleration, (g)100.60.5U-4.0.4.2+0" 0.3111"oM'la0q0.1-4,- PGA-3-20 Hz-h-10 Hz--X-5 Hz---2.5 Hz-40-1 Hz.0.5 Hz0 4-0.0010.01 0.1 110Spectral acceleration, (g)Figure 42c. PVNGS UR profile median amplification factors and log standard deviation as a function ofspectral acceleration.

Source: Figure 57 from LCI (LCI, 2015d).55 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 32.4 Soil Hazard and Ground Motion Response Spectrum (GMRS) Calculations

2.4.1 Background

The subject analyses calculate the soil hazard at the PVNGS site using: (1) the 2015 PVNGS seismicsources (Section 2.1); (2) the 2015 SWUS GMPEs (Section 2.2); and (3) site specific amplification factors (Section 2.3). For the purposes of these analyses, the "PVNGS site" control point was chosen asUnit 2/free-field elevation (LCI, 2015d, S&A, 2015, and Section 3.2). The site specific amplification factors (Section 2.3) that convert ground motions from reference rock (shear wave velocity of 760 m/s) toPVNGS soil were applied in the these calculations.

The soil seismic hazard analysis conformed to therequirements of the SPID (EPRI, 2013) and the results can be used for the seismic evaluation andscreening of nuclear plant structures,

systems, and components.

2.4.2 Methodology

The methodology for seismic hazard calculations is well established in the technical literature (e.g.,McGuire, 2004). The calculation of soil hazard was implemented with Approach 3 (REI, 2001).Ground motions were modeled for seven spectral frequencies (Section 2.2.4.1).

The spectral frequencies were PGA (equivalent to 100 Hz spectral acceleration),

20 Hz spectral acceleration (SA), 10 Hz SA, 5 HzSA, 2.5 Hz SA, 1 Hz SA, and 0.5 Hz SA. Seismic hazard was calculated for 20 ground motionamplitudes, which were 0.000001g, 0.0005g, 0.001g, 0.005g, 0.01g, 0.015g, 0.03g, 0.05g, 0.075g, 0.1g,0.15g, 0.3g, 0.5g, 0.75g, 1.0g, 1.5g, 3.0g, 5.0g, 7.5g and 10.0g. All ground motion equations represented spectral acceleration at 5% of critical

damping, so results presented in this report represent spectralacceleration at 5% of critical damping.Steps used in calculating the mean soil horizontal GMRS were as follows.1. The seismic hazard (annual frequency of exceedance) representing ground motion at the top of thesoil column was calculated using the inputs described in Sections 2.2 and 2.3, for the seven spectralfrequencies indicated above.2. Spectral amplitudes corresponding to 104, 10-5, and 10-6 annual frequencies of exceedence weredetermined by log-log interpolation of the total mean hazard curves at the seven spectral frequencies indicated above.3. Uniform hazard response spectra (UHRS) for 10-4, 10-, and 10-6 annual frequencies of exceedence were calculated by anchoring mean spectral shapes determined from site amplification calculations (Section 2.3) to the spectral amplitudes calculated in step 2 above. These mean spectral shapes werecalculated using site amplification calculations for amplitudes, magnitudes, and distances consistent with 10-4, 105', and 10-6 annual frequencies of exceedence.

For spectral frequencies below 0.5 Hz, l/Tscaling was assumed (where T is spectral period).

This is consistent with requirements for seismicbuilding codes (e.g., Building Seismic Safety Council, 2009). This step gave smooth UHRS forspectral frequencies between 100 Hz and 0.1 Hz.4. The GMRS was calculated at each spectral frequency from the UHRS at that frequency derived instep 3 above. The following equations (U.S.NRC, 2007) were used to calculate the GMRS values:10- UHRSAmplitude Ratio AR -4 UHRSDesign Factor DF = max(], 0.6 x A8)GMRS = max(10-4UHRS x DF, 0.45 x 10-5 UHRS)56 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3These steps resulted in horizontal UHRS and GMRS applicable at the top of soil (free-field) for thePVNGS site.2.4.3 ResultsThe 104, 10-', and 10-6 UHRS for the seven spectral frequencies for which hazards were calculated areshown in Table 9.Table 9. Mean 104, 10-', and 10-6 UHRS. Source: Table 1 from LCI (LCI, 2015e)UHRS acceleration, gSpectral frequency 104 105 10-60.5 Hz 0.0613 0.146 0.3641.0 Hz 0.226 0.553 1.292.5 Hz 0.297 0.806 1.825.0 Hz 0.371 0.956 1.8010 Hz 0.275 0.659 1.2320 Hz 0.207 0.491 0.930PGA 0.170 0.429 0.860Figure 43 plots mean total soil hazard curves for the seven spectral frequencies (PGA, 20 Hz SA, 10 HzSA, 5 Hz SA, 2.5 Hz SA, 1 Hz SA, and 0.5 Hz SA) at which hazard calculations were conducted.

Theindividual hazard curves are also documented in tabular form in Table 10. The relative relationship among soil hazard curves is typical for nuclear plant sites in the U.S.Figure 44 plots 104, 10-5, and 10-6 horizontal UHRS and GMRS. The individual 104, 10-5, and 10-6horizontal UHRS and GMRS are also documented in tabular form in Table 11.Figures 45 and 46 show fractile soil hazard curves for 10 Hz SA and 1 Hz SA, respectively.

The fractilesoil hazard curves indicate a range in hazard of a factor of about 4 between the 0.84 and 0.16 fractile for10 Hz SA and a factor of about 7 for 1 Hz. The fractile range reflects the consistency in ground motionamong GMPEs controlling the hazard at 10 Hz SA and 1 Hz SA.The sensitivity of soil hazard to the three velocity profiles (Base-Case, Lower-Range, and Upper-Range) used in the site response analysis (Section 2.3) are plotted in Figures 47 and 48 for 10 Hz SA and 1 HzSA, respectively.

Figure 47 shows that the Upper-Range profile produces the highest hazard curve at 10Hz SA, and the Lower-Range profile produces the lowest hazard curve. This is consistent with the Upper-Range profile being stiffer and shallower than either the Base-Case or the Lower-Range profiles.

Astiffer, shallower profile produces more high frequency

response, and the stiff material remains almostlinear at high amplitudes.

Figure 48 shows that for 1 Hz SA, the Lower-Range profile produces thehighest hazard at low amplitudes (SA less than 0.2g) but produces the lowest hazard at high amplitudes (SA greater than 0.8g). This is consistent with the Lower-Range profile being softer and deeper thaneither the Base-Case and Upper-Range profiles.

A softer, deeper profile results in more low-frequency response at low amplitudes, but non-linear effects in soft materials reduce the response at highamplitudes.

57 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Soil Hazard by Spectral Frequency at Palo VerdeCCrCC4'1E-31E-41E-51E-65 HZ2.5 Hz-10 Hz-1 Hz-20 Hz--PGA-0.5 HZ1E-7 +-0.010.1 1Spectral acceleration Eel10Figure 43. Total mean soil hazard curves for seven spectral frequencies.

Source: Figure 1 from LCI (LCI,2015e).Mean Horizontal Soil UHRS and GMRS10.S1.2 -106 UHRS--10"6 UHRS-GMRS_____ ____ __ _ UHRSS0.1 --UHRS0.010.1 1 10 100Spectral frequency, HzFigure 44. 10", 10-5, and 10-6 mean horizontal soil UHRS and GMRS. Source: Figure 2 from LCI (LCI,2015e).58 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table 10. Total mean soil hazard for seven spectral frequencies.

Source: Table 2 from LCI (LCI, 2015e).Spectralacceleration g 0.5 Hz 1 Hz 2.5 Hz 5 Hz 10 Hz 20 Hz PGA0.000001 1.60E+00 1.60E+00 1.60E+00 1.60E+00 1.60E+00 1.60E+00 1.60E+000.0005 3.80E-01 1.05E+00 1.21E+00 1.05E+00 7.86E-01 7.33E-01 7.74E-010.001 2.25E-01 7.17E-01 8.90E-01 7.56E-01 5.16E-01 4.68E-01 4.81E-010.005 3.31E-02 1.99E-01 2.43E-01 2.02E-01 1.14E-01 1.OOE-01 9.18E-020.01 9.05E-03 8.83E-02 1.07E-01 8.77E-02 4.53E-02 3.98E-02 3.3 1E-020.015 3.71E-03 4.85E-02 5.95E-02 4.85E-02 2.42E-02 2.12E-02 1.63E-020.03 6.73E-04 1.37E-02 1.74E-02 1.48E-02 7.35E-03 6.23E-03 4.18E-030.05 1.73E-04 4.54E-03 6.OOE-03 5.63E-03 2.90E-03 2.29E-03 1.42E-030.075 5.79E-05 1.73E-03 2.40E-03 2.54E-03 1.36E-03 9.88E-04 5.94E-040.1 2.69E-05 8.39E-04 1.23E-03 1.43E-03 7.88E-04 5.32E-04 3.20E-040.15 9.34E-06 2.93E-04 4.77E-04 6.37E-04 3.58E-04 2.17E-04 1.33E-040.3 1.63E-06 4.78E-05 9.75E-05 1.57E-04 8.34E-05 4.1 OE-05 2.69E-050.5 4.48E-07 1.30E-05 3.08E-05 5.29E-05 2.32E-05 9.51E-06 6.53E-060.75 1.55E-07 4.58E-06 1.20E-05 1.98E-05 6.73E-06 2.34E-06 1.69E-06I 7.07E-08 2.11 E-06 5.85E-06 8.81E-06 2.40E-06 7.48E-07 5.63E-071.5 2.22E-08 6.40E-07 1.90E-06 2.24E-06 4.46E-07 1.23E-07 1.OOE-073 2.60E-09 6.07E-08 1.88E-07 1.06E-07 1.47E-08 3.46E-09 3.38E-095 4.61E-10 8.43E-09 2.52E-08 6.52E-09 8.70E-10 1.71E-10 1.90E-107.5 1.05E-10 1.54E-09 4.36E-09 5.33E-10 8.23E-11 1.23E-11 1.49E-1110 3.48E-11 4.28E-10 1.16E-09 7.70E-11 1.49E-11 1.67E-12 2.12E-1259 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table 11. Mean Soil Horizontal UHRS and GMRS for Palo Verde. Source: Table 3 from LCI (LCI,2015e)Freq, 10-4 UHRS (g) 10"5 UHRS (g) 10-6 UHRS (g) GMRS (g)Hz100 1.70E-01 4.29E-0I 8.60E-01 2.14E-0190 1.69E-01 4.30E-01 8.63E-01 2.14E-0180 1.69E-01 4.30E-01 8.66E-01 2.14E-0170 1.68E-01 4.31E-01 8.69E-01 2.14E-0160 1.68E-01 4.33E-01 8.73E-01 2.15E-0150 1.68E-01 4.35E-01 8.78E-01 2.16E-0140 1.70E-01 4.39E-01 8.86E-01 2.18E-0135 1.72E-01 4.43E-01 8.91E-01 2.20E-0130 1.77E-01 4.50E-01 8.98E-01 2.24E-0125 1.87E-01 4.64E-01 9.11 E-01 2.32E-0120 2.07E-01 4.91E-01 9.30E-01 2.48E-0115 2.27E-01 5.29E-01 1.01E+00 2.68E-0112.5 2.49E-01 5.81E-01 1.09E+00 2.94E-0110 2.75E-01 6.59E-01 1.23E+00 3.32E-019 2.86E-01 6.89E-01 1.28E+00 3.47E-018 3.02E-01 7.27E-01 1.34E+00 3.66E-017 3.22E-01 7.84E-01 1.43E+00 3.94E-016 3.48E-01 8.64E-01 1.59E+00 4.32E-015 3.71E-01 9.56E-01 1.80E+00 4.75E-014 3.75E-01 9.99E-01 1.96E+00 4.93E-013.5 3.63E-01 9.92E-01 2.02E+00 4.87E-013 3.37E-01 9.23E-01 1.98E+00 4.53E-012.5 2.97E-01 8.06E-01 1.82E+00 3.96E-012 2.65E-01 6.82E-01 1.72E+00 3.39E-011.5 2.80E-01 6.68E-01 1.48E+00 3.37E-011.25 2.91E-01 6.92E-01 1.40E+00 3.49E-011 2.26E-01 5.53E-01 1.29E+00 2.77E-010.9 1.91E-01 4.79E-01 1.17E+00 2.39E-010.8 1.54E-01 3.93E-01 9.97E-01 1.96E-010.7 1.18E-01 3.02E-01 7.82E-01 1.50E-010.6 8.61E-02 2.14E-01 5.58E-01 1.07E-010.5 6.13E-02 1.46E-01 3.64E-01 7.36E-020.4 4.90E-02 1.17E-01 2.91E-01 5.89E-020.35 4.29E-02 1.02E-01 2.55E-01 5.15E-020.3 3.68E-02 8.76E-02 2.18E-01 4.42E-020.25 3.07E-02 7.30E-02 1.82E-01 3.68E-020.2 2.45E-02 5.84E-02 1.46E-01 2.95E-020.15 1.84E-02 4.38E-02 1.09E-01 2.21E-020.125 1.53E-02 3.65E-02 9.1OE-02 1.84E-020.1 1.23E-02 2.92E-02 7.28E-02 1.47E-0260 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 310 Hz Soil Hazard Fractiles at Palo Verde1E-3Elw-05 rctl....E5 -0.16 ftactileE-61E-70.01 0.1 1. 10.10 Hz spectral acceleration, gFigure 45. Fractile soil hazard curves for 10 Hz SA. Source: Figure 5 from LCI (LCI, 2015e).1 Hz Soil Hazard Fractiles at Palo Verde1E-3Co1E-4El-CIE-71~ 0.16 fractile-0.84 fractile-O.S fractile--0.16 fractile0.010.1 1.1 Hz spectral acceleration, g10.Figure 46. Fractile soil hazard curves for 1 Hz SA. Source: Figure 6 from LCI (LCI, 2015e).61 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 310 Hz Sensitivity to Soil Profile at Palo Verde1E-3Cr0CC491E-41E-51E-6U -Upper-Range I. -Profile-Upper-Range Profile-Base-Case Profile-Lower-Range ProfileIC _70.010.111010 Hz spectral acceleration (g)Figure 47. Sensitivity to the BC, UR, and LR velocity profiles described in Section 2.3 for 10 Hz SA(curves are not weighted by profile weights).

Source: Figure 7 from LCI (LCI, 2015e).1 Hz Sensitivity to Soil Profile at Palo Verde1E-3C01E-41E-5CWIC-I" 1E-61E-70.010.1 11 Hz spectral acceleration (g)10Figure 48. Sensitivity to the BC, UR, and LR velocity profiles described in Section 2.3 for I Hz SA(curves are not weighted by profile weights).

Source: Figure 8 from LCI (LCI, 2015e).62 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 33 Plant Design BasisThe PVNGS design basis is identified in the Updated Final Safety Analysis Report (UFSAR, Rev. 17,Sections 2.5 and 3.7).3.1 SSE Description of Spectral ShapeThe 10 CFR 100 Appendix A site characterization SSE was established in UFSAR Section 2.5 as peakground acceleration (PGA) of 20% gravity (0.20g).

The seismic analysis of all Seismic Category Istructures was performed utilizing a Design Spectral Response Curve anchored at a PGA value of 0.25g.A PGA of 0.25g thus constitutes the design value for PVNGS, which bounds the 0.20g sitecharacterization SSE (licensing basis).For PVNGS Unit 1, 2, and 3 the design earthquake is defined in terms of a PGA and a Regulatory Guide1.60 design response spectral shape. Table 12 and Figure 49 shows the spectral acceleration values as afunction of frequency for the 5% damped horizontal Design Specteral Response Curve.Table 12. PVNGS Unit 1, 2, and 3 0.25g PGA horizontal design spectral response curve, 5% damping.0.25 0.122.50 0.789.00 0.6533.00 0.25100.00 0.2563 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3PVNGS 0.25g PGA Ilofzontal Desin SpechMI Response Curve, 5% Daaqp~g10.10.010.1110100Frtqwwyc (Hz)Figure 49. PVNGS Unit 1, 2, and 3 0.25g PGA horizontal design spectral response curve, 5% damping.Source: (S&A, 2015a)3.2 Control Point Elevation UFSAR Section 2.5.2.6 defines the site characterization SSE vibratory ground motion, which isessentially based on free-field surface motions, as applicable to the grade level of the plant.The 0.25g design level of acceleration and the associated design spectral response curve are applied toboth the plant grade and the foundation level for the purpose of structural design and soil-structure interaction analyses.

Additional discussion pertaining to the control point elevation can be found in S&Aproject report (S&A, 2015).The control point, which is representative of Unit 1, 2, and 3, is therefore defined as Unit 2/free-field (plant grade, foundation) level.64 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 34 Screening Evaluation Following completion of the seismic hazard reevaluation, as requested in the 10 CFR 50.54(f) letter, ascreening process was performed to determine if a seismic risk evaluation was needed. The horizontal GMRS determined from the hazard reevaluation was used to characterize the amplitude of the newseismic hazard at PVNGS. The screening evaluation was based upon a comparison of the GMRS withthe 5% damped horizontal Design Spectral Response Curve. Figure 50 shows a comparison between theplant design and the site GMRS that was calculated for Unit 2 as described in Section 2.4 above. Inaccordance with SPID Section 3, a screening evaluation was performed as described below.Horizontal GMRS to Design Spectral Response Curve Comparison IU.3I1I0.1F-Hodzonti Deslg~m---Hodmtm Desin0.25g 5% daping-SSHAC Level 3 Horizontal GMAS, S6 damping.j0.01 .0.1I toFhequency JHz)100Figure 50. PVNGS Unit 1, 2, and 3 horizontal GMRS to design spectral response curve comparison.

Source: ( S&A, 2015a).4.1 Risk Evaluation Screening (1 to 10 Hz)The Design Spectral Response Curve used for the design of Seismic Category 1 Structures, Systems andComponents (SSCs) exceeds the GMRS response curve in the frequency range of I to 10 Hz.Consistent with the guidance provided in the 10 CFR 50.54(f) letter (U.S.NRC, 2012a), APS is therefore not required to perform a Seismic Risk Evaluation for the PVNGS site.65 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 34.2 High Frequency Screening

(>10 Hz)The Design Spectral Response Curve used for the design of Seismic Category I Structures, Systems andComponents (SSCs) also exceeds the GMRS response curve in the frequency range above 10 Hz.Consistent with the guidance provided in the 10 CFR 50.54(f) letter (U.S.NRC, 2012a), APS is therefore not required to perform the High Frequency Confirmation for the PVNGS site.4.3 Spent Fuel Pool Evaluation Screening (1 to 10 Hz)The Design Spectral Response Curve used for the design of Seismic Category 1 Structures, Systems andComponents (SSCs) exceeds the GMRS response curve in the frequency range of 1 to 10 Hz.Consistent with the guidance provided in the 10 CFR 50.54(f) letter (U.S.NRC, 2012a), APS is therefore not required to perform a spent fuel pool evaluation for the PVNGS site.5 Interim ActionsPVNGS fully meets the criteria discussed in the SPID (EPRI, 2013) for screening out.Interim actions are not, therefore, needed or required for the PVNGS site.6 Conclusions In accordance with the 10 CFR 50.54(f) request for information, a seismic hazard and screening evaluation was performed for the PVNGS site. A GMRS was developed for purpose of screening foradditional evaluations in accordance with the SPID. Based on the results of the PVNGS screening evaluation, no further action is required for the NTTF Recommendation 2.1 seismic review.7 References 7.1 (Abrahamson et al., 2014) Abrahamson, N.A., Silva, W.J., and Kamai, R., Summary of the ASK14ground motion relation for active crustal regions, Earthquake

Spectra,

v. 30, 1025-1055.

7.2 (Al Atik et al. 2014) Al Atik, L., Kottke, A., Abrahamson, N., and Hollenback, J., Kappa (K)Scaling of ground-motion prediction equations using an inverse random vibration theory approach, Bulletin of the Seismological Society of America,

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v. 80, no. 2, 257-282.69 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Appendix A. Tabulated DataTable A-1. Fourier adjustment factors from reference rock conditions to local rock conditions and theirweights.

Source: Table I from LCI (LCI, 2015b).SWUS to PVNGS Adjustment Factor (Fourier-amplitude Space)Abbrev: TF1 TF2 TF3 TF4 TF5 TF6 TF7 TF8 TF9LB LB LB Median Median Median UB UB UBProfile,

Profile, Profile,

Profile, Profile,

Profile, Profile,

Profile, Profile,Freq. LB Median UB LB Median UB LB Median UB(Hz) kappa kappa kappa kappa kappa kappa kappa kappa kappa(0.09) (0.12) (0.09) (0.12) (0.16) (0.12) (0.09) (0.12) (0.09)0.1000 1.0136 1.0086 0.9993 0.8916 0.8873 0.8790 0.8598 0.8556 0.84770.1080 1.0218 1.0165 1.0063 0.8871 0.8824 0.8736 0.8528 0.8483 0.83980.1166 1.0313 1.0255 1.0144 0.8821 0.8771 0.8676 0.8451 0.8403 0.83120.1259 1.0424 1.0360 1.0240 0.8766 0.8712 0.8611 0.8367 0.8316 0.82190.1359 1.0574 1.0504 1.0372 0.8721 0.8663 0.8554 0.8291 0.8236 0.81320.1468 1.0768 1.0691 1.0546 0.8684 0.8622 0.8505 0.8219 0.8160 0.80500.1585 1.0999 1.0914 1.0754 0.8643 0.8576 0.8451 0.8140 0.8077 0.79590.1711 1.1279 1.1185 1.1009 0.8597 0.8526 0.8391 0.8054 0.7987 0.78610.1848 1.1660 1.1555 1.1358 0.8571 0.8493 0.8349 0.7981 0.7910 0.77750.1995 1.1927 1.1811 1.1594 0.8549 0.8466 0.8310 0.7910 0.7833 0.76890.2154 1.1895 1.1770 1.1536 0.8524 0.8435 0.8268 0.7830 0.7748 0.75940.2326 1.1852 1.1718 1.1467 0.8496 0.8400 0.8220 0.7742 0.7654 0.74910.2512 1.1856 1.1711 1.1441 0.8501 0.8397 0.8203 0.7678 0.7584 0.74090.2712 1.1867 1.1710 1.1419 0.8511 0.8398 0.8189 0.7612 0.7511 0.73240.2929 1.1878 1.1709 1.1395 0.8522 0.8400 0.8175 0.7538 0.7431 0.72310.3162 1.1890 1.1707 1.1368 0.8533 0.8402 0.8159 0.7456 0.7341 0.71280.3415 1.1950 1.1752 1.1385 0.8580 0.8438 0.8174 0.7393 0.7271 0.70430.3687 1.2037 1.1821 1.1423 0.8578 0.8425 0.8141 0.7334 0.7203 0.69600.3981 1.2136 1.1902 1.1469 0.8537 0.8372 0.8068 0.7268 0.7128 0.68690.4299 1.2251 1.1996 1.1526 0.8490 0.8313 0.7987 0.7193 0.7043 0.67680.4642 1.2429 1.2149 1.1636 0.8464 0.8274 0.7924 0.7133 0.6973 0.66780.5012 1.2688 1.2380 1.1817 0.8466 0.8260 0.7884 0.7092 0.6920 0.66050.5412 1.3013 1.2673 1.2051 0.8474 0.8252 0.7847 0.7046 0.6861 0.65250.5843 1.3476 1.3096 1.2403 0.8521 0.8281 0.7843 0.7014 0.6816 0.64550.6310 1.4077 1.3648 1.2871 0.8586 0.8325 0.7851 0.6987 0.6774 0.63880.6813 1.4269 1.3801 1.2954 0.8659 0.8375 0.7861 0.6956 0.6728 0.63150.7356 1.4146 1.3645 1.2744 0.8755 0.8445 0.7887 0.6931 0.6686 0.62440.7943 1.4047 1.3511 1.2549 0.8901 0.8561 0.7952 0.6929 0.6665 0.61910.8577 1.3940 1.3366 1.2342 0.9073 0.8699 0.8033 0.6928 0.6643 0.61340.9261 1.3821 1.3207 1.2118 0.9275 0.8863 0.8132 0.6926 0.6619 0.60731.0000 1.3731 1.3074 1.1914 0.9546 0.9089 0.8283 0.6943 0.6611 0.60241.0798 1.3666 1.2962 1.1724 0.9900 0.9390 0.8494 0.6980 0.6620 0.59881.1659 1.3594 1.2839 1.1520 1.0338 0.9764 0.8762 0.7019 0.6629 0.594870 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table A-1. Fourier adjustment factors from reference rock conditions to local rock conditions and theirweights.

Source: Table I from LCI (LCI, 2015b).SWUS to PVNGS Adjustment Factor (Fourier-amplitude Space)Abbrev: TF1 TF2 TF3 TF4 TF5 TF6 TF7 TF8 TF9LB LB LB Median Median Median UB UB UBProfile,

Profile, Profile,

Profile, Profile,

Profile, Profile,

Profile, Profile,Freq. LB Median UB LB Median UB LB Median UB(Hz) kappa kappa kappa kappa kappa kappa kappa kappa kappa(0.09) (0.12) (0.09) (0.12) (0.16) (0.12) (0.09) (0.12) (0.09)1.2589 1.3512 1.2703 1.1300 1.0758 1.0114 0.8998 0.7062 0.6639 0.59061.3594 1.3483 1.2614 1.1117 1.0777 1.0082 0.8886 0.7142 0.6681 0.58881.4678 1.3478 1.2543 1.0943 1.0773 1.0026 0.8747 0.7246 0.6743 0.58831.5849 1.3471 1.2464 1.0757 1.0767 0.9963 0.8598 0.7364 0.6813 0.58801.7113 1.3460 1.2378 1.0557 1.0759 0.9894 0.8439 0.7496 0.6893 0.58791.8478 1.3446 1.2282 1.0344 1.0748 0.9817 0.8268 0.7645 0.6984 0.58821.9953 1.3435 1.2184 1.0121 1.0739 0.9739 0.8090 0.7821 0.7093 0.58922.1544 1.3435 1.2089 0.9895 1.0739 0.9663 0.7909 0.8033 0.7228 0.59162.3263 1.3431 1.1984 0.9654 1.0735 0.9579 0.7716 0.8280 0.7387 0.59512.5119 1.3424 1.1869 0.9398 1.0730 0.9487 0.7512 0.8522 0.7535 0.59662.7123 1.3421 1.1751 0.9132 1.0728 0.9392 0.7300 0.8575 0.7508 0.58352.9286 1.3413 1.1620 0.8851 1.0721 0.9288 0.7075 0.8570 0.7424 0.56553.1623 1.3399 1.1476 0.8553 1.0710 0.9173 0.6837 0.8561 0.7332 0.54653.4145 1.3419 1.1351 0.8264 1.0726 0.9073 0.6606 0.8573 0.7252 0.52803.6869 1.3434 1.1213 0.7960 1.0738 0.8963 0.6362 0.8583 0.7164 0.50863.9811 1.3451 1.1067 0.7644 1.0751 0.8846 0.6110 0.8594 0.7070 0.48844.2987 1.3525 1.0956 0.7347 1.0811 0.8757 0.5873 0.8641 0.7000 0.46944.6416 1.3605 1.0837 0.7040 1.0874 0.8662 0.5627 0.8692 0.6924 0.44985.0119 1.3751 1.0756 0.6751 1.0991 0.8598 0.5396 0.8785 0.6872 0.43135.4117 1.3923 1.0680 0.6458 1.1129 0.8536 0.5162 0.8895 0.6823 0.41265.8434 1.4148 1.0625 0.6173 1.1309 0.8493 0.4934 0.9039 0.6788 0.39446.3096 1.4430 1.0592 0.5892 1.1534 0.8466 0.4710 0.9219 0.6767 0.37656.8129 1.4746 1.0560 0.5606 1.1787 0.8441 0.4481 0.9421 0.6747 0.35827.3564 1.5156 1.0569 0.5334 1.2114 0.8448 0.4264 0.9683 0.6752 0.34087.9433 1.5606 1.0574 0.5054 1.2474 0.8452 0.4039 0.9971 0.6756 0.32298.5770 1.6136 1.0599 0.4776 1.2898 0.8472 0.3817 1.0310 0.6772 0.30519.2612 1.6782 1.0659 0.4507 1.3414 0.8520 0.3603 1.0722 0.6810 0.288010.0000 1.7503 1.0722 0.4233 1.3990 0.8570 0.3383 1.1183 0.6850 0.270410.7978 1.8346 1.0808 0.3962 1.4664 0.8639 0.3167 1.1721 0.6905 0.253111.6591 1.9374 1.0941 0.3702 1.5486 0.8746 0.2959 1.2378 0.6990 0.236512.5893 2.0549 1.1088 0.3441 1.6425 0.8863 0.2750 1.3129 0.7084 0.219913.5936 2.1894 1.1246 0.3179 1.7500 0.8989 0.2541 1.3988 0.7185 0.203114.6780 2.3499 1.1446 0.2926 1.8783 0.9149 0.2338 1.5014 0.7313 0.186915.8489 2.5422 1.1692 0.2680 2.0321 0.9346 0.2142 1.6243 0.7470 0.171271 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table A-i. Fourier adjustment factors from reference rock conditions to local rock conditions and theirweights.

Source: Table I from LCI (LCI, 2015b).SWUS to PVNGS Adjustment Factor (Fourier-amplitude Space)Abbrev: TF1 TF2 TF3 TF4 TF5 TF6 TF7 TF8 TF9LB LB LB Median Median Median UB UB UBProfile,

Profile, Profile,

Profile, Profile,

Profile, Profile,

Profile, Profile,Freq. LB Median UB LB Median UB LB Median UB(Hz) kappa kappa kappa kappa kappa kappa kappa kappa kappa(0.09) (0.12) (0.09) (0.12) (0.16) (0.12) (0.09) (0.12) (0.09)17.1133 2.7672 1.1962 0.2438 2.2119 0.9562 0.1949 1.7680 0.7643 0.155818.4785 3.0319 1.2258 0.2201 2.4235 0.9798 0.1759 1.9371 0.7832 0.140619.9526 3.3536 1.2614 0.1975 2.6806 1.0083 0.1578 2.1427 0.8059 0.126221.5443 3.7485 1.3041 0.1761 2.9963 1.0424 0.1407 2.3950 0.8332 0.112523.2631 4.2270 1.3518 0.1556 3.3787 1.0805 0.1244 2.7006 0.8637 0.099425.1189 4.8118 1.4050 0.1361 3.8461 1.1231 0.1088 3.0743 0.8977 0.086927.1227 5.5426 1.4671 0.1179 4.4303 1.1727 0.0943 3.5412 0.9373 0.075429.2864 6.4784 1.5422 0.1014 5.1783 1.2327 0.0811 4.1391 0.9853 0.064831.6228 7.6667 1.6277 0.0861 6.1281 1.3010 0.0688 4.8983 1.0399 0.055034.1455 9.1952 1.7252 0.0722 7.3499 1.3789 0.0577 5.8748 1.1022 0.046136.8695 11.1888 1.8369 0.0597 8.9434 1.4682 0.0477 7.1486 1.1736 0.038139.8107 13.8284 1.9655 0.0486 11.0533 1.5710 0.0388 8.8350 1.2557 0.031042.9866 17.3805 2.1143 0.0389 13.8925 1.6900 0.0311 11.1045 1.3508 0.024946.4159 22.2896 2.2920 0.0307 17.8164 1.8320 0.0245 14.2409 1.4644 0.019650.1187 29.2648 2.5099 0.0238 23.3918 2.0062 0.0190 18.6974 1.6036 0.015254.1170 39.2659 2.7684 0.0181 31.3858 2.2128 0.0145 25.0872 1.7687 0.011658.4341 53.9344 3.0774 0.0135 43.1106 2.4598 0.0108 34.4589 1.9662 0.008663.0957 75.9811 3.4500 0.0098 60.7328 2.7576 0.0078 48.5447 2.2042 0.006368.1292 110.005 3.9029 0.0069 87.9283 3.1197 0.0055 70.2824 2.4936 0.004473.5642 164.031 4.4589 0.0048 131.113 3.5641 0.0038 104.800 2.8488 0.003179.4328 252.802 5.1544 0.0032 202.069 4.1200 0.0026 161.517 3.2932 0.002085.7696 404.226 6.0417 0.0021 323.104 4.8292 0.0017 258.262 3.8601 0.001392.6119 671.328 7.1753 0.0013 536.603 5.7353 0.0010 428.915 4.5843 0.0008100.O0000 1160.96 8.6394 0.0008 927.980 6.9056 0.0006 741.749 5.5197 0.000572 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table A-2. Scaled HF input control motions.

Source: LCI (LCI, 2015a).Freq.(Hz)

HFI1(g) HF2(g) HF3(g) HF4(g) HF5(g) HF6(g) HF7(g) HF8(g) HF9(g) HF10(g) HF11(g)100 1.00E-02 1.80E-02 3.24E-02 5.83E-02 1.05E-01 1.56E-01 2.31E-01 3.44E-01 5.33E-01 8.27E-01 1.50E+0090 1.00E-02 1.81E-02 3.25E-02 5.85E-02 1.05E-01 1.56E-01 2.33E-01 3.46E-01 5.37E-01 8.33E-01 1.51E+0080 1.01E-02 1.81E-02 3.27E-02 5.88E-02 1.06E-01 I1.57E-01 2.35E-01 3.48E-01 5.40E-01 8.40E-01 I1.52E+00 70 1.01E-02 1.82E-02 3.28E-02 5.91E-02 1.06E-01 I1.58E-01 2.36E-01 3.51E-01 5.45E-01 8.48E-01 1.54E+0060 1.02E-02 1.83E-02 3.30E-02 5.94E-02 1.07E-01 I1.59E-01 2.39E-01 3.54E-01 5.50E-01 8.57E-01 1.55E+0050 1.03E-02 1.85E-02 3.32E-02 5.98E-02 1.08E-01 1.60E-01 2.41E-0I 3.58E-01 5.56E-01 8.68E-01 1.57E+0040 1.08E-02 1.94E-02 3.50E-02 6.30E-02 1.13E-01 1.68E-0I 2.57E-01 3.82E-01 5.92E-01 9.22E-01 1.67E+0033 1.13E-02 2.03E-02 3.66E-02 6.58E-02 1.18E-01 1.76E-01 2.72E-01 4.04E-01 6.26E-01 9.71E-01 1.76E+0030 1.17E-02 2.11E-02 3.79E-02 6.82E-02 1.23E-01 1.82E-01 2.83E-01 4.21E-01 6.53E-01 1.01E+00 1.84E+0025 1.25E-02 2.26E-02 4.06E-02 7.31E-02 1.31E-01 1.95E-01 3.07E-01 4.55E-01 7.06E-01 1.1OE+00 1.99E+0020 1.36E-02 2.45E-02 4.41E-02 7.94E-02 1.43E-01 2.12E-01 3.38E-01 5.02E-01 7.78E-01 1.21E+00 2.20E+0015 1.61E-02 2.90E-02 5.22E-02 9.40E-02 1.69E-01 2.51E-01 4.OOE-01 5.95E-01 9.22E-01 1.43E+00 2.59E+0013 1.75E-02 3.16E-02 5.68E-02 1.02E-0I 1.84E-01 2.73E-01 4.36E-01 6.47E-01 L.OOE+00 1.55E+00 2.81E+0010 2.05E-02 3.70E-02 6.66E-02 1.20E-0I 2.16E-01 3.20E-01 5.04E-01 7.49E-01 1.16E+00 1.78E+00 3.22E+009 2.08E-02 3.74E-02 6.73E-02 1.21E-01 2.18E-01 3.24E-01 5.1OE-0I 7.57E-01 1.17E+00 1.80E+00 3.27E+008 2.1OE-02 3.78E-02 6.81E-02 1.23E-01 2.21E-01 3.27E-01 5.16E-0I 7.67E-01 1.19E+00 1.83E+00 3.33E+007 2.13E-02 3.83E-02 6.90E-02 1.24E-0I 2.23E-01 3.32E-01 5.24E-01 7.78E-01 1.21E+00 1.87E+00 3.39E+006 2.15E-02 3.88E-02 6.98E-02 1.26E-01 2.26E-01 3.36E-01 5.28E-01 7.84E-01 1.22E+00 1.90E+00 3.44E+005 2.18E-02 3.92E-02 7.06E-02 1.27E-0I 2.29E-01 3.40E-01 5.31E-01 7.89E-01 1.22E+00 1.93E+00 3.50E+004 1.91E-02 3.44E-02 6.19E-02 1.1 IE-01 2.01E-01 2.98E-01 4.67E-01 6.94E-01 1.08E+00 1.71E+00 3.1OE+003.3 1.71E-02 3.07E-02 5.53E-02 9.96E-02 1.79E-01 2.66E-01 4.18E-01 6.21E-01 9.64E-01 1.54E+00 2.80E+003 1.55E-02 2.78E-02 5.01E-02 9.02E-02 1.62E-01 2.41E-01 3.79E-01 5.63E-01 8.73E-01 1.40E+00 2.55E+002.5 1.28E-02 2.31E-02 4.15E-02 7.47E-02 1.34E-01 2.OOE-01 3.14E-01 4.66E-01 7.22E-01 1.17E+00 2.13E+002 1.09E-02 1.96E-02 3.54E-02 6.36E-02 1.15E-01 1.70E-01 2.64E-01 3.93E-01 6.09E-0I 1.02E+00 1.84E+001.5 7.78E-03 1.40E-02 2.52E-02 4.53E-02 8.16E-02 1.21E-01 1.90E-01 2.82E-01 4.38E-01 7.41E-01 1.34E+001.3 6.57E-03 1.18E-02 2.13E-02 3.83E-02 6.90E-02 1.02E-01 1.61E-01 2.40E-01 3.72E-01 6.34E-01 1.15E+00I 4.45E-03 8.01E-03 1.44E-02 2.59E-02 4.67E-02 6.93E-02 1.1OE-01 1.64E-01 2.54E-01 4.57E-01 8.28E-010.9 3.85E-03 6.94E-03 1.25E-02 2.25E-02 4.04E-02 6.01E-02 9.51E-02 1.41E-01 2.19E-01 3.94E-01 7.15E-010.8 3.28E-03 5.91E-03 1.06E-02 1.91E-02 3.44E-02 5.11 E-02 8.05E-02 1.20E-01 1.85E-01 3.34E-01 6.07E-0173 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table A-2. Scaled HF input control motions.

Source: LCI (LCI, 2015a).Freq.(Hz)

HF1(g) HF2(g) HF3(g) HF4(g) HF5(g) HF6(g) HF7(g) HF8(g) HF9(g) HF10(g) HF11(g)0.7 2.74E-03 4.92E-03 8.86E-03 1.60E-02 2.87E-02 4.26E-02 6.67E-02 9.90E-02 1.54E-01 2.78E-01 5.04E-010.6 2.19E-03 3.93E-03 7.08E-03 1.27E-02 2.29E-02 3.41E-02 5.28E-02 7.84E-02 1.22E-01 2.20E-01 4.00E-010.5 1.66E-03 3.00E-03 5.39E-03 9.71E-03 1.75E-02 2.59E-02 3.97E-02 5.90E-02 9.15E-02 1.67E-01 3.02E-010.4 1.18E-03 2.12E-03 3.81E-03 6.86E-03 1.23E-02 1.83E-02 2.80E-02 4.16E-02 6.46E-02 1.20E-01 2.18E-010.33 8.71E-04 1.57E-03 2.82E-03 5.08E-03 9.14E-03 1.36E-02 2.08E-02 3.08E-02 4.78E-02 9.05E-02 1.64E-010.3 7.38E-04 1.33E-03 2.39E-03 4.30E-03 7.75E-03 1.15E-02 1.77E-02 2.62E-02 4.07E-02 7.78E-02 1.41E-010.25 5.37E-04 9.67E-04 1.74E-03 3.13E-03 5.64E-03 8.38E-03 1.30E-02 1.93E-02 2.99E-02 5.82E-02 1.06E-010.2 3.73E-04 6.71E-04 1.21E-03 2.17E-03 3.91E-03 5.81E-03 9.1OE-03 1.35E-02 2.1OE-02 4.17E-02 7.56E-020.15 2.25E-04 4.06E-04 7.30E-04 1.31E-03 2.36E-03 3.51E-03 5.58E-03 8.29E-03 1.29E-02 2.63E-02 4.78E-020.13 1.75E-04 3.16E-04 5.68E-04 1.02E-03 1.84E-03 2.73E-03 4.38E-03 6.50E-03 1.01E-02 2.1OE-02 3.80E-020.1 1.02E-04 1.84E-04 3.32E-04 5.97E-04 1.07E-03 1.60E-03 2.44E-03 3.62E-03 5.61E-03 1.19E-02 2.15E-0274 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table A-3. Scaled LF input control motions.

Source: LCI (LCI, 2015a).Freq.(Hz)

LF1(g) LF2(g) LF3(g) LF4(g) LF5(g) LF6(g) LF7(g) LF8(g) LF9((g) LF10(g) LF11(g)100 L.OOE-02 1.71E-02 2.94E-02 5.03E-02 8.63E-02 1.27E-01 1.86E-01 2.73E-01 4.51E-01 7.44E-01 1.50E+0090 L.OOE-02 1.72E-02 2.94E-02 5.04E-02 8.63E-02 1.27E-01 1.86E-01 2.73E-01 4.51E-01 7.52E-01 1.52E+0080 L.00E-02 1.72E-02 2.94E-02 5.04E-02 8.64E-02 1.27E-01 1.86E-01 2.74E-01 4.52E-01 7.61E-01 1.53E+0070 1.OOE-02 1.72E-02 2.94E-02 5.05E-02 8.65E-02 1.27E-01 1.87E-01 2.74E-0I 4.52E-01 7.71E-0I 1.55E+0060 1.OOE-02 1.72E-02 2.95E-02 5.05E-02 8.66E-02 1.27E-01 1.87E-01 2.74E-01 4.53E-01 7.83E-01 1.58E+0050 1.01E-02 1.72E-02 2.95E-02 5.06E-02 8.67E-02 1.27E-01 1.87E-01 2.75E-01 4.53E-01 7.97E-01 1.61E+0040 1.03E-02 1.76E-02 3.02E-02 5.18E-02 8.89E-02 1.30E-01 1.92E-01 2.82E-01 4.65E-0I 8.30E-01 1.67E+0033 1.05E-02 1.80E-02 3.09E-02 5.29E-02 9.07E-02 1.33E-01 1.96E-01 2.88E-01 4.76E-0I 8.60E-01 1.73E+0030 1.06E-02 1.82E-02 3.12E-02 5.35E-02 9.17E-02 1.35E-01 1.99E-01 2.92E-01 4.82E-01 8.98E-0I 1.81E+0025 1.09E-02 1.86E-02 3.19E-02 5.47E-02 9.37E-02 1.38E-01 2.04E-01 2.99E-01 4.94E-0I 9.73E-01 1.96E+0020 1.11E-02 1.91E-02 3.27E-02 5.61E-02 9.61E-02 1.41E-01 2.1OE-01 3.08E-01 5.08E-01 1.07E+00 2.17E+0015 1.20E-02 2.06E-02 3.54E-02 6.06E-02 1.04E-01 1.53E-01 2.28E-01 3.34E-01 5.52E-0I 1.28E+00 2.58E+0013 1.25E-02 2.15E-02 3.68E-02 6.30E-02 1.08E-01 1.59E-01 2.37E-01 3.48E-01 5.74E-01 1.39E+00 2.81E+0010 1.35E-02 2.32E-02 3.98E-02 6.82E-02 1.17E-01 1.72E-01 2.56E-01 3.75E-0l 6.19E-01 1.63E+00 3.29E+009 1.39E-02 2.37E-02 4.07E-02 6.97E-02 1.20E-01 1.76E-01 2.61E-01 3.83E-01 6.33E-01 1.68E+00 3.38E+008 1.42E-02 2.44E-02 4.18E-02 7.16E-02 1.23E-01 1.80E-01 2.67E-01 3.93E-01 6.48E-01 1.73E+00 3.49E+007 1.46E-02 2.51E-02 4.30E-02 7.37E-02 1.26E-01 1.85E-01 2.75E-01 4.03E-01 6.66E-01 1.79E+00 3.61E+006 1.54E-02 2.64E-02 4.52E-02 7.74E-02 1.33E-01 1.95E-01 2.87E-01 4.22E-01 6.96E-01 1.85E+00 3.73E+005 1.64E-02 2.81E-02 4.82E-02 8.26E-02 1.42E-01 2.08E-01 3.04E-01 4.47E-01 7.38E-01 1.92E+00 3.88E+004 1.75E-02 2.99E-02 5.13E-02 8.79E-02 1.51E-01 2.21E-01 3.21E-01 4.72E-01 7.78E-01 1.74E+00 3.50E+003.3 1.82E-02 3.12E-02 5.35E-02 9.17E-02 1.57E-01 2.31E-01 3.33E-01 4.89E-0I 8.06E-01 1.60E+00 3.22E+003 1.84E-02 3.16E-02 5.41E-02 9.27E-02 1.59E-01 2.33E-01 3.35E-01 4.92E-01 8.13E-01 1.47E+00 2.96E+002.5 1.88E-02 3.23E-02 5.53E-02 9.48E-02 1.62E-01 2.38E-01 3.40E-0I 5.00E-01 8.25E-01 1.24E+00 2.51E+002 1.66E-02 2.84E-02 4.86E-02 8.34E-02 1.43E-01 2.1OE-01 2.75E-01 4.04E-01 6.67E-01 1.07E+00 2.15E+001.5 1.42E-02 2.44E-02 4.18E-02 7.16E-02 1.23E-01 1.80E-01 2.32E-01 3.41E-01 5.63E-01 8.12E-01 1.64E+001.3 1.32E-02 2.26E-02 3.87E-02 6.64E-02 1.14E-01 1.67E-01 2.13E-01 3.13E-01 5.17E-01 7.1OE-01 1.43E+00I 9.46E-03 1.62E-02 2.78E-02 4.76E-02 8.16E-02 1.20E-01 1.44E-01 2.11 E-01 3.49E-01 5.30E-01 1.07E+000.9 8.69E-03 1.49E-02 2.55E-02 4.37E-02 7.50E-02 1.10E-01 1.30E-01 1.90E-01 3.14E-01 4.62E-01 9.31E-010.8 7.90E-03 1.35E-02 2.32E-02 3.98E-02 6.82E-02 1.00E-01 1.16E-01 1.70E-01 2.80E-01 3.96E-01 7.99E-010.7 7.10E-03 1.22E-02 2.08E-02 3.57E-02 6.12E-02 8.99E-02 1.01E-01 1.49E-01 2.46E-0l 3.33E-01 6.71E-0175 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table A-3. Scaled LF input control motions.

Source: LCI (LCI, 2015a).Freq.(Hz)

LFI(g) LF2(g) LF3(g) LF4(g) LFS(g) LF6(g) LF7(g) LF8(g) LF9(g) LF10(g) LF11(g)0.6 6.18E-03 1.06E-02 1.81E-02 3.11E-02 5.33E-02 7.83E-02 8.60E-02 1.26E-01 2.08E-01 2.80E-01 5.64E-010.5 5.21E-03 8.93E-03 1.53E-02 2.62E-02 4.50E-02 6.60E-02 7.03E-02 1.03E-01 1.70E-01 2.31E-01 4.66E-010.4 4.19E-03 7.19E-03 1.23E-02 2.11E-02 3.62E-02 5.31E-02 5.66E-02 8.31E-02 1.37E-01 1.71E-01 3.44E-010.33 3.47E-03 5.96E-03 1.02E-02 1.75E-02 3.OOE-02 4.40E-02 4.69E-02 6.89E-02 1.14E-01 I1.32E-01 2.66E-010.3 3.15E-03 5.40E-03 9.25E-03 1.58E-02 2.72E-02 3.99E-02 4.25E-02 6.24E-02 1.03E-01 1.15E-01 2.33E-010.25 2.61E-03 4.47E-03 7.66E-03 1.31E-02 2.25E-02 3.30E-02 3.52E-02 5.16E-02 8.52E-02 8.96E-02 1.81E-010.2 2.08E-03 3.57E-03 6.12E-03 1.05E-02 1.80E-02 2.64E-02 2.81E-02 4.13E-02 6.82E-02 6.71E-02 1.35E-010.15 1.59E-03 2.73E-03 4.67E-03 8.01E-03 1.37E-02 2.01E-02 2.15E-02 3.15E-02 5.20E-02 4.48E-02 9.03E-020.13 1.39E-03 2.38E-03 4.08E-03 7.OOE-03 1.20E-02 1.76E-02 1.88E-02 2.75E-02 4.55E-02 3.66E-02 7.39E-020.1 1.04E-03 1.79E-03 3.06E-03 5.25E-03 8.99E-03 1.32E-02 1.41E-02 2.07E-02 3.41E-02 2.14E-02 4.32E-0276 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table A-4. SAFs and uncertainty for seven spectral frequencies at associated reference rock amplitudes for PVNGS base-case profile.

Source:Table 22 from LCI (LCI, 2015d).Low Frequency 0.5 Hz 1 Hz 2.5 HzMedian Median MedianAmp. (g) SAF 01nn5AF) Amp. (g) SAF (In(SAF)

Amp. (g) SAF OI11SAF)5.21E-03 1.16E+00 2.50E-01 9.46E-03 2.51E+00 2.94E-01 1.88E-02 1.83E+00 2.95E-018.93E-03 1.17E+00 2.50E-01 1.62E-02 2.53E+00 2.96E-01 3.23E-02 1.81E+00 2.90E-011.53E-02 1.17E+00 2.54E-01 2.78E-02 2.54E+00 3.04E-01 5.53E-02 1.77E+00 2.88E-012.62E-02 1.18E+00 2.58E-01 4.76E-02 2.53E+00 3.03E-01 9.48E-02 1.75E+00 2.87E-014.50E-02 1.20E+00 2.64E-01 8.16E-02 2.59E+00 2.93E-01 1.62E-01 1.75E+00 2.78E-016.60E-02 1.21E+00 2.70E-01 1.20E-01 2.58E+00 2.95E-01 2.38E-01 1.71E+00 2.85E-017.03E-02 1.24E+00 2.80E-01 1.44E-01 2.63E+00 2.93E-01 3.40E-01 1.71E+00 2.93E-011.03E-01 1.27E+00 2.79E-01 2.11 E-01 2.63E+00 2.90E-01 5.OOE-01 1.69E+00 3.08E-011.70E-01 1.32E+00 3.01E-01 3.49E-01 2.57E+00 3.01E-01 8.25E-01 1.61E+00 3.19E-012.31E-01 1.45E+00 3.28E-01 5.30E-01 2.42E+00 3.06E-01 1.24E+00 1.48E+00 3.OOE-014.66E-01 I1.77E+00 3.94E-01 1.07E+00 2.01E+00 3.27E-01 2.51E+00 1.20E+00 3.29E-01High Frequency_

5 Hz 10 Hz 20 Hz PGAA (g) Median Amp (g) Median Amp (g) Median aIn(5A) Amp (g) MedianSAF SAF SAF SAF 01n(SAF)2.18E-02 1.84E+00 3.58E-01 2.05E-02 1.55E+00 4.56E-01 1.36E-02 1.71E+00 5.1OE-01 1.OOE-02 1.83E+00 3.57E-013.92E-02 1.79E+00 3.49E-01 3.70E-02 1.49E+00 4.43E-01 2.45E-02 1.63E+00 4.89E-01 1.80E-02 1.78E+00 3.42E-017.06E-02 1.73E+00 3.50E-01 6.66E-02 1.39E+00 4.45E-01 4.41E-02 1.51E+00 4.67E-01 3.24E-02 1.71E+00 3.33E-011.27E-01 1.64E+00 3.44E-01 1.20E-01 1.27E+00 4.30E-01 7.94E-02 1.36E+00 4.36E-01 5.83E-02 1.61E+00 3.18E-012.29E-01 1.56E+00 3.32E-01 2.16E-01 1.14E+00 4.11 E-0I 1.43E-01 1.22E+00 3.97E-01 1.05E-01 1.51E+00 2.97E-0I3.40E-01 1.45E+00 3.32E-01 3.20E-01 1.02E+00 4.04E-01 2.12E-01 1.1OE+00 3.76E-01 1.56E-01 1.41E+00 2.93E-015.31E-01 1.32E+00 3.18E-01 5.04E-01 8.87E-01 3.84E-0I 3.38E-01 9.72E-01 3.43E-01 2.31E-01 1.31E+00 2.76E-017.89E-01 1.16E+00 3.21E-01 7.49E-01 7.57E-01 3.77E-01 5.02E-01 8.59E-01 3.20E-0I 3.44E-01 1.20E+00 2.70E-011.22E+00 9.75E-01 3.38E-01 1.16E+00 6.09E-01 3.57E-01 7.78E-01 7.40E-01 2.96E-01 5.33E-01 1.08E+00 2.67E-011.93E+00 7.77E-01 3.45E-01 1.78E+00 4.99E-0I 3.45E-01 1.21E+00 6.62E-01 2.88E-01 8.27E-01 9.81E-01 2.74E-0I3.50E+00 5.51E-01 3.50E-01 3.22E+00 3.78E-01 2.96E-01 2.20E+00 5.49E-01 2.65E-01 1.50E+00 8.32E-01 2.62E-0177 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table A-5. SAFs and uncertainty for seven spectral frequencies at associated reference rock amplitudes for PVNGS lower-range profile.Source: Table 23 from LCI (LCI, 2015d).Low Frequency 0.5 Hz 1 Hz 2.5 HzMedian Median MedianAmp. (g) SAF 01n(SAF) Amp. (g) SAF IIn(SAF)

Amp. (g) SAF aln(SAF)5.21E-03 1.33E+00 2.71E-01 9.46E-03 2.91E+00 2.97E-01 1.88E-02 2.17E+00 2.90E-018.93E-03 1.34E+00 2.76E-01 1.62E-02 2.86E+00 2.95E-01 3.23E-02 2.11E+00 2.78E-011.53E-02 1.35E+00 2.79E-01 2.78E-02 2.81E+00 2.93E-01 5.53E-02 2.04E+00 2.86E-012.62E-02 1.36E+00 2.96E-01 4.76E-02 2.75E+00 2.91E-01 9.48E-02 1.98E+00 2.83E-014.50E-02 1.39E+00 2.90E-01 8.16E-02 2.66E+00 2.98E-01 1.62E-01 1.86E+00 2.90E-016.60E-02 1.43E+00 3.07E-01 1.20E-01 2.55E+00 2.99E-01 2.38E-01 1.79E+00 2.86E-017.03E-02 1.47E+00 3.15E-01 1.44E-01 2.50E+00 2.98E-01 3.40E-01 1.72E+00 2.98E-011.03E-01 1.52E+00 3.39E-01 2.11 E-01 2.38E+00 3.03E-01 5.OOE-01 1.62E+00 3.09E-011.70E-01 1.64E+00 3.50E-01 3.49E-01 2.16E+00 3.29E-01 8.25E-01 1.45E+00 3.29E-012.31E-01 1.89E+00 3.60E-01 5.30E-01 1.92E+00 3.62E-01 1.24E+00 1.26E+00 3.36E-014.66E-01 2.25E+00 3.60E-01 1.07E+00 1.67E+00 3.45E-01 2.51E+00 9.61E-01 3.47E-01High Frequency 5 Hz 10 Hz 20 Hz PGAMeinMedian MedianAmp. (g) SAF 0in(SAF) Amp. (g) Median (SAF) Amp- (g) San O.SAF) A______ _____ ____ SAF GnA) Am.() SAF OnSF Amp. (g) Median SAF OYln(SAF) 2.18E-02 1.81E+00 3.49E-01 2.05E-02 1.51E+00 4.44E-01 1.36E-02 1.68E+00 4.85E-01 1.OOE-02 1.84E+00 3.37E-013.92E-02 1.76E+00 3.59E-01 3.70E-02 1.42E+00 4.40E-01 2.45E-02 1.57E+00 4.71E-01 1.80E-02 1.76E+00 3.35E-017.06E-02 1.70E+00 3.49E-01 6.66E-02 1.32E+00 4.25E-01 4.41E-02 1.44E+00 4.39E-01 3.24E-02 1.67E+00 3.16E-011.27E-01 1.56E+00 3.34E-01 1.20E-01 1.17E+00 4.09E-01 7.94E-02 1.26E+00 4.06E-01 5.83E-02 1.54E+00 3.OOE-012.29E-01 1.45E+00 3.25E-01 2.16E-01 1.03E+00 3.98E-01 1.43E-01 1.11E+00 3.74E-01 1.05E-01 1.43E+00 2.88E-013.40E-01 1.32E+00 3.34E-01 3.20E-01 9.04E-01 3.96E-01 2.12E-01 9.96E-01 3.54E-01 1.56E-01 1.33E+00 2.84E-015.31E-01 1.17E+00 3.23E-01 5.04E-01 7.58E-01 3.73E-01 3.38E-01 8.63E-01 3.17E-01 2.31E-01 1.21E+00 2.68E-017.89E-01 9.98E-01 3.24E-01 7.49E-01 6.35E-01 3.75E-01 5.02E-01 7.56E-0I 2.98E-01 3.44E-01 1.09E+00 2.61E-011.22E+00 8.1IE-0I 3.28E-01 1.16E+00 5.09E-01 3.41E-0I 7.78E-01 6.51E-0I 2.80E-01 5.33E-01 9.70E-01 2.62E-011.93E+00 6.1OE-0I 3.59E-01 1.78E+00 4.08E-01 3.27E-01 1.21E+00 5.71E-0I 2.86E-01 8.27E-01 8.59E-01 2.80E-013.50E+00 4.25E-01 3.58E-01 3.22E+00 3.08E-01 3.05E-01 2.20E+00 4.65E-0I 2.79E-01 1.50E+00 7.09E-01 2.76E-0178 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Table A-6. SAFs and uncertainty for seven spectral frequencies at associated reference rock amplitudes for PVNGS upper-range profile.Source: Table 24 from LCI (LCI, 2015d).Low Frequency 0.5 Hz 1 Hz 2.5 HzMedian Median MedianAmp. (g) SAF Amp. (g) SAF (FIn(SAF)

Amp. (g) SAF OIn(SAF)5.21E-03 1.07E+00 2.46E-01 9.46E-03 1.95E+00 3.04E-01 1.88E-02 1.58E+00 2.61E-018.93E-03 1.07E+00 2.49E-01 1.62E-02 1.96E+00 3.1OE-0I 3.23E-02 1.56E+00 2.74E-011.53E-02 1.08E+00 2.49E-01 2.78E-02 1.97E+00 3.13E-01 5.53E-02 i.55E+00 2.70E-012.62E-02 1.08E+00 2.52E-01 4.76E-02 2.01E+00 3.17E-01 9.48E-02 1.52E+00 2.71E-0I4.50E-02 1.09E+00 2.52E-01 8.16E-02 2.02E+00 3.18E-01 1.62E-01 1.50E+00 2.74E-0I6.60E-02 1.1OE+00 2.58E-01 1.20E-01 2.1OE+00 3.28E-01 2.38E-01 1.48E+00 2.84E-017.03E-02 1.12E+00 2.60E-01 1.44E-01 2.15E+00 3.26E-01 3.40E-01 1.47E+00 2.99E-011.03E-01 1.14E+00 2.66E-01 2.11 E-01 2.24E+00 3.26E-01 5.OOE-01 1.46E+00 2.97E-011.70E-01 1.17E+00 2.79E-01 3.49E-0I 2.34E+00 3.21E-01 8.25E-01 1.46E+00 3.27E-012.31E-01 1.25E+00 3.01E-01 5.30E-01 2.47E+00 3.17E-01

!.24E+00 1.49E+00 3.35E-014.66E-01 1.44E+00 3.67E-01 1.07E+00 2.28E+00 3.04E-01 2.51E+00 1.32E+00 3.17E-01High Frequency 5 Hz 10 Hz 20 Hz PGAMedian Median Median MedianAmp. (g) SAF 01n(SAF) Amp. (g) SAF 01n(SAE) Amp. (g) SAF Ot.(SAF)

Amp. (g) SAF OIn(SAF)2.18E-02 1.75E+00 3.53E-01 2.05E-02 1.49E+00 4.63E-01 I1.36E-02 1.69E+00 5.19E-01 L.OOE-02 1.79E+00 3.61E-0I3.92E-02 1.73E+00 3.63E-01 3.70E-02 1.44E+00 4.55E-01 2.45E-02 1.64E+00 5.04E-01 1.80E-02 1.75E+00 3.53E-017.06E-02 1.70E+00 3.57E-01 6.66E-02 1.39E+00 4.45E-01 4.41E-02 1.54E+00 4.80E-01 3.24E-02 1.70E+00 3.38E-011.27E-01 1.65E+00 3.47E-01 1.20E-01 1.29E+00 4.32E-01 7.94E-02 1.42E+00 4.52E-01 5.83E-02 1.61E+00 3.22E-012.29E-01 1.57E+00 3.36E-01 2.16E-01 1.17E+00 4.20E-01 1.43E-01 1.27E+00 4.25E-01 1.05E-01 1.52E+00 3.08E-013.40E-01 1.50E+00 3.37E-01 3.20E-01 1.08E+00 4.18E-01 2.12E-01 1.17E+00 4.06E-01 1.56E-01 1.45E+00 3.04E-015.31E-0I 1.38E+00 3.34E-01 5.04E-01 9.64E-01 3.95E-01 3.38E-01 1.04E+00 3.72E-01 2.31E-01 1.35E+00 2.88E-017.89E-01 1.25E+00 3.23E-01 7.49E-01 8.30E-01 3.91E-01 5.02E-01 9.17E-01 3.39E-01 3.44E-01 1.25E+00 2.75E-011.22E+00 1.09E+00 3.27E-01 1.16E+00 6.98E-01 3.75E-01 7.78E-01 8.02E-01 3.17E-01 5.33E-01 1.13E+00 2.69E-011.93E+00 8.95E-01 3.20E-01 1.78E+00 5.68E-01 3.28E-01 1.21E+00 7.11E-01 2.74E-01 8.27E-01 1.03E+00 2.57E-013.50E+00 6.59E-01 3.60E-01 3.22E+00 4.31E-01 3.21E-01 2.20E+00 5.94E-O1 2.76E-01 1.50E+00 8.90E-01 2.70E-0179 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Appendix B SSC PPRP Endorsement LetterThis appendix provides the Participatory Peer Review Panel Closure Letter from (APS, 2015).February 26,2015Dr. Ross HartlebLCI Project Manager, Palo Verde Nuclear Generating Station (PVNGS) Seismic Hazard Evaluation ProjectLettis Consultants International, Inc.27441 Tourney Road, Suite 220Valencia, CA 91355Subject-PVNGS SSHAC Level 3 Seismic Source Characterization

Dear Dr. Hartleb:

On March 12, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued a request forinformation pursuant to 10CFR50.54(f),

requiring that all operating nuclear plants in the U.S.perform a site-specific Probabilistic Seismic Hazard Analysis (PSHA) and develop a Ground MotionResponse Spectrum (GMRS) in accordance with Regulatory Guide 1.208 for comparison to theplant license Safe Shutdown Earthquake (SSE) ground motion. Licensees are required to re-evaluate the seismic hazard using present-day NRC regulatory criteria and guidance.

For plants inthe western U.S., including the PVNGS, the directive requires that the site-specific PSHA beperformed using the Senior Seismic Hazard Analysis Committee (SSHAC1,

2) Level 3 process todevelop the Seismic Source Characterization (SSC) model.In accordance with the requirements for a SSHAC Level 3 study, the PVNGS SSC Participatory PeerReview Panel ("PPRP")

is pleased to issue this PPRP Closure Letter containing our findings withrespect to the PVNGS SSC Project The PPRP was actively engaged in the review of all phases andactivities of the Project's implementation.

These phases included development of the Project Plan,planning and execution of the Technical Integration (TI) Team's evaluation and integration activities, and review of the TI Team's documentation of the SSC model. These phases are at thecore of the SSHAC process.In accordance with NRC guidance for SSHAC projects, the role of the PPRP is to conduct a reviewof both the process followed and the technical assessments made by the TI Team. Accordingly, thisletter documents the activities that the PPRP has carried out to perfbrm its review of the adequacyof the process followed, and its findings regarding the technical adequacy of the SSC.I Budnitz, R.I., G. Apostolakis, D.M. Boore, LS. Cluff, 1(L Coppersmith, CA. Cornell, and PA. Morris(1997). Recommendations for Probabilistic Seismic Hazard Analysis:

Guidance on Uncertainty andthe Use of Experts (known as the "Senior Seismic Hazard Analysis Committee Report".

or "SSHACGuideline"),

NUREG/CR-6372, U.S. Nuclear Regulatory Commission, TIC; 235076, Washington, D.C.2 USNRC (2012). Practical Implementation GuidelinesforSSHAC Level3 and 4 Hazard Studies,NUREG-2117, U.S. Nuclear Regulatory Commission, Washington, D.C.80 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3PPRP Activities for the SSC Peer ReviewThe fundamental idea of a participatory peer review process entails the continual review of aproject from its start to its completion.

Thus, proper participatory peer review requires adequateopportunities during the conduct of the project for the PPRP to understand the data being used,the analyses performed, the TI Team's evaluations and integration of the technical bases for itsassessments, and the completeness and clarity of the documentation.

Participatory peer reviewalso involves occasions for the PPRP to provide its reviews and comments in written form duringthe conduct of the project, such that their observations and recommendations can be considered by the TI Team in a timely manner prior to the completion of the project Written comments bythe PPRP serve to document the review process and provide part of the formal recorddocumenting that all aspects of the SS-AC process have been satisfactorily conducted.

The activities of the PPRP for the PVNGS SSC are summarized in the table below, which includeswritten reviews during the various stages of the project These activities directly addressed theconduct of the PVNGS SSC and the development of the SSC Report.Date PPRP ActivityJanuary 21, 2013 SSC Kickoff Meeting ("Workshop 0"); PPRP members attended inperson as observers January 23, 2013 PPRP submitted review comments on the Project Plan via emailApril 9-11, 2013 SSC Workshop No. 1: Significant Issues and Data Needs;PPRP members attended in person as observers April 24, 2013 PPRP submitted written review comments on Kick-off MeetingJune 5, 2013 PPRP submitted written review comments on Workshop 1July 10, 2013 TI working meeting No. 4: PPRP members Savage andMachette attend portion of TI working meeting by phone asobservers August 27-28, 2013 TI working meeting No. 5: PPRP member Rockwell attendsportion of TI working meeting by phone as observerSeptember 24-26, 2013 SSC Workshop No. 2: Alternative Interpretations; PPRP membersattended in person as observers October 23,2013 PPRP submitted written review comments on Workshop No. 2February 4-6, 2014 Field Review of Geologic Mapping:

PPRP members attendedin person as observers March 24,2014 PPRP submitted written review comments of Field Review ofGeologic MappingApril 23-25, 2014 SSC Workshop No. 3: Preliminary Model and HazardFeedback:

PPRP members attended in person as activeparticipants 81 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Date PPRP ActivityMay 5, 2014 PPRP submitted written review comments on Workshop 3June 18, 2014 Update on SSC Activities; PPRP members attended via webinar asobservers July 10-11, 2014 SSC Final Briefing; PPRP members attended in personAugust 1, 2014 Update on SSC Activities; PPRP representatives attended viawebinar as observers January 12. 2015 Submittal of review comments on SSC Report, transmittal 1 &2January 17, 2015 Submittal of review comments on SSC Report, transmittal 3January 19-22, 2015 Submittal of PPRP written review comments on SSC Reporttransmittals 1-3 and on TI Team's responses to PPRP writtenreview commentsFebruary 17-19, 2015 Submittal of PPRP written review comments on PVNGS SSCDraft Report transmittal 4 and on TI Team's responses toPPRP written review commentsFebruary 19-25, 2015 Teleconference call to resolve remaining issues with SSCDraft Report (2/19) and review of TI Team's responses toteleconference call issuesFebruary 26,2015 Submittal of PVNGS SSC PPRP Closure LetterThe activities listed above are those that directly addressed the conduct of the PVNGS SSC and thedevelopment of the PVNGS SSC Report, The PPRP has concluded that its ongoing review andfeedback interactions with the TI Team during the conduct of the PVNGS SSC Project activities fully met the expectations for a SSHAC Level 3 study. From the presentation of the plans forconducting the PVNGS SSC at the start of the project to the completion of the PVNGS SSC Report,the TI Team provided multiple and effective communications with the PPRP. Webinars andwritten communications allowed the PPRP to fully understand the technical support for the TITeam's assessments.

The TI Team provided written responses to PPRP comments documenting that all comments had been adequately considered during the conduct of the work and thecompilation of its documentation.

SSHAC Technical ReviewThe role of the PPRP in the review of the technical aspects of the project is specified in NUREG-2117 (USNRC, 2012) as follows:"The PPRP fulfills two parallel roles, the first being technical review. This meansthat the PPRP is charged with ensuring that the full range of data, models, andmethods have been duly considered in the assessment and also that all technical decisions are adequately justified and documented.

82 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3The responsibility of the PPRP is to provide clear and timely feedback to theTi/TFI and project manager to ensure that any technical or process deficiencies are identified at the earliest possible stage so that they can be corrected.

Morecommonly, the PPRP provides its perspectives and advice regarding the manner inwhich ongoing activities can be improved or carried out more effectively.

In termsof technical review, a key responsibility of the PPRP is to highlight any data,models or proponents that have not been considered.

Beyond completeness, it isnot the responsibility of the PPRP to judge the weighting of the logic trees in detail,but rather to judge the justification provided for the models included or excluded, and for the weights applied to the logic-tree branches."

Consistent with this USNRC guidance, the PPRP reviewed at multiple times during the projectthe TI Team's analyses and evaluations of data, models, and methods.

These reviews includedconference calls, post-workshop

meetings, written comments, and the review of drafts of theSSC Report. Through these reviews, the PPRP communicated feedback to the Ti Teamregarding data and approaches that did not appear to have been considered, suggestions formethods being used within the technical community, and recommendations for ways that thedocumentation could be improved to include more discussion of the technical bases for theassessments.

Examples of PPRP feedback regarding technical aspects of the project can be found in thewritten comments provided following workshops and field trips and during the review of thedraft final report. The TI Team was responsive to the questions,

comments, and suggestions made by the PPRP relative to the technical aspects of the project.

Therefore, the PPRPconcludes that the technical aspects of the project have been adequately addressed.

SSHAC Process ReviewAs explained in NUREG-2117 (IJSNRC, 2012), the SSHAC process consists of two important activities, described as follows:'The fundamental goal of a SSHAC process is to carry out properly and documentcompletely the activities of evaluation and integration, defined as:e Evaluation:

The consideration of the complete set of data, models, andmethods proposed by the larger technical community that are relevant tothe hazard analysis.

e Integration:

Representing the center, body, and range of technically defensible interpretations in light of the evaluation process (i.e., informedby the assessment of existing data, models, and methods)."

These activities are essential to any SSHAC Level study and to both new models and refinements to existing models (such as the PVNGS SSC).During the Evaluation phase of the PVNGS SSC, the TI Team considered new data, models, andmethods that have become available in the technical community since the previous PVNGS PSHA83 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3projects were completed in 1993 and 2012. In particular, the TI Team incorporated newearthquake occurrence models and carried out additional geologic mapping.

The PPRP concluded that the TI Team conducted a satisfactory evaluation process and that this process has beensufficiently documented in the SSC report.During the Integration phase of the project, an updated SSC model was developed for purposes ofthe PVNGS PSHA. SSHAC guidelines require that the technical bases for the SSC model bedocumented thoroughly in the SSC report. The SSC document demonstrates the consideration bythe TI Team of the existence of seismic-source data and models that have become available sincethe previous PVNGS SSC model was developed.

During the entire course of the PVNGS Project, The TI Team maintained close coordination withthe SW[JS ground-motion characterization project to assure that the PVNGS SSC will connectseamlessly with the GMC model.Based on the review of the Evaluation and Integration activities conducted by the TI Team, aswell as the documentation of these activities in the SSC report, the PPRP concludes that theSSHAC level 3 process has been adequately conducted.

Conclusion Based on its review of the PVNGS SSC, the PPRP concludes that the process and technical aspectsof the analysis fully meet accepted guidance and current expectations for a SSHAC Level 3 study.We appreciate the opportunity to provide our review of the project.Sincerely, PVNGS SSC PPRP MembersWilliam U. Savage, Chair Michael N. Machette Thomas KI Rockwell84 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Appendix C GMC PPRP Endorsement LetterThis appendix provides the Participatory Peer Review Panel Closure Letter from (GeoPentech, 2015).February 24, 2015Dr. Carola Di Alessandro SWUS Project ManagerGeoPentech, Inc.525 N. Cabrillo Park Drive, Suite 280Santa Ana, CA 92701

Subject:

Participatory Peer Review Panel Closure Letter, Southwest United StatesGround Motion Characterization Level 3 SSHAC Project

Dear Dr. Di Alessandro:

The Participatory Peer Review Panel (PPRP, also referred to herein as the 'Panel")

forthe Southwest United States (SWUS) Ground Motion Characterization (GMC) Project ispleased to issue this PPRP Closure Letter. Herein we describe our participation in theSWUS GMC SSHAC Level 3 project and present our findings.

Pursuant to theguidelines for a SSHIAC Level 3 study (NUREGICR-6372; NUREG-2117),

the PPRPwas engaged at all stages of the project, including review of the final Project Plan,Workshop agendas and participant lists; the planning of the evaluation and modelintegration activities; and review of the project documentation.

Throughout the project,the Panel reviewed and provided regular feedback on both the process followed, andthe technical assessments made, by the Technical Integrator (TI) Team. By this letterthe Panel documents the activities it has performed in the course of its review, itsassessment of the process followed relative to SSHAC Level 3 expectations, and itsassessment of the technical rationale underlying the GMC model.PPRP Activities in Support of the SWUS GMC ReviewIn a SSHAC Level 3 study, the PPRP fufitlls two roles. The first is that of technical review, in which the Panel ensures that the full range of data, models and methods areconsidered and that technical decisions and judgments are adequately justified anddocumented.

The second is that of process review, under which the Panel ensures thatthe study maintains conformity with the SSHAC Level 3 guidelines.

To fulfill these roles,the Panel requires adequate opportunities to gain understanding of the data being used,the analyses being performed, the TI Team's evaluations of data and models, and thetechnical justifications for the TI Team's model decisions.

The table below summarizes the formal project activities in which the Panel participated.

Fulfilling these roles alsorequires the Panel to provide regular feedback to the TI Team during the course of theproject.

In addition to verbal feedback during Working Meetings and Workshops, thePanel provided written comments and recommendations at key stages of the project.Those written submittals are also noted in the table.85 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3DatePPRP ActivityJune 21, 2012 orking Meeting #1 (Planning).

All PPRP members attended.

July 18, 2012 orking Meeting #2 (Planning).

All PPRP members attended.

August 27, 2012 ick-off Meeting.

All PPRP members attended.

September 17, 2012 PRP submittal of written comments on the Project Plan.October 8, 2012 IVorking Meeting #3. PPRP representatives attended as observers.

November 3, 2012 PRP submittal of written comments on revised Project Plan.November 29, 2012 PRP submittal of PPRP endorsement letter for Project PlaniDecember 10, 2012 orking Meeting #4. PPRP representatives attended as observers.

February 11, 2013 orking Meeting #5. PPRP representatives attended as observers.

March 19-21, 2013 orkshop #1: Critical issues and Data Needs. All PPRP members attended asrvers. The PPRP provided verbal feedback to the TI Team at the end of__ach day of the WorkshopApril 12, 2013 orking Meeting #6. PPRP representatives attended as observers.

April 21, 2013 PRP submittal of written comments on Workshop

1. 1.May 23, 2013 orking Meeting #7. PPRP representatives attended as observers.

June 24, 2013 orking Meeting #8. PPRP representatives attended as observers.

July 16, 2013 orking Meeting #9. PPRP representatives attended as observers.

August 21, 2013 lorking Meeting #10. PPRP representatives attended as observers.

October 2, 2013 Porking Meeting #11. PPRP representatives attended as observers.

October 15, 2013 Norking Meeting #12. PPRP representatives attended as observers.

October 22-24, 2013 Workshop

1. 2: Proponent Models and Alternative Interpretations.

All PPRPmbers attended as observers.

The PPRP provided verbal feedback to the TITeam at the end of each day of the Workshop.

November 26, 2013 Working Meeting #13. PPRP representatives attended as observers.

December 3, 2013 PRP submittal of written comments on Workshop

1. 2.January 2, 2014 orking Meeting #14. PPRP representatives attended as observers.

January 28-29, 2014 Special Working Meeting.

All PPRP members attended as observers.

March 3, 2014 orking Meeting #15. PPRP representatives attended as observers.

March 10-12, 2014 orkshop #3: Preliminary GMC Models and Hazard Feedback.

All PPRPmbers attended as participants.

The PPRP provided verbal feedback to the1"1 Team at the end of each day of the Workshop.

March 24, 2014 orking Meeting #16. PPRP representatives attended as observers.

0pn1 21, 2014 PPRP submittal of written comments on Workshop

1. 3.May 14, 2014 PRP Closure Pre-Briefing.

All PPRP members attended as participants.

July 17-18, 2014 PPRP Closure Briefing.

Al] PPRP members attended as participants.

December 13, 2D14 Submittal No. 1 of PPRP written review comments on SWUS GMC Report:Comments on SWUS GMC Report Rev.0, Chapters 7, 10, 11, 12,13, andAppendices L, M, N, and R.December 16, 2014 Teleconference, PPRP and TI Team, to discuss the PPRP written reviewcomments, Submittal No. 1.January 5, 2015 Submittal No. 2 of PPRP written review comments on SWUS GMC Report:Comments on SWUS GMC Report Rev.0, Chapters 6, 8, 9, 14, and Appendices H, I, J, K, 0, and 0.January 7, 2015 Teleconference, PPRP and TI Team, to discuss the PPRP written reviewcomments, Submittal No. 2.January 26, 2015 leeconference, PPRP and TI Team, to discuss the main modifications otroduced in SWUS GMC Report Draft Rev.1.February 9, 2015 Teleconference, PPRP and TI Team, to discuss observations from PPRP partialreview of SWUS GMC Report Draft Rev.1.February 16, 2015 Teleconference, PPRP and Project Manager to discuss project completion schedule.

February 20, 2015 Submittal No. 3 of PPRP written review comments on SWUS GMC Report:Comments on SWUS GMC Report Draft Rev.1.86 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3The PPRP finds that the level of ongoing review it was able to undertake, and theopportunities afforded the PPRP to provide feedback to the TI Team, met theexpectations for a SSHAC Level 3 study. Interactions with the TI Team provided ampleopportunity for the Panel to gain an understanding of the technical bases for the TITeam's evaluations.

The Panel also was given adequate opportunity to query the T1Team, especially in Workshop

1. 3 and in the Pre-Closure Briefing and Closure Briefing, to assess the justification provided for their model decisions.

The TI Team providedwritten responses to each formal PPRP submittal, and in nearly every case the PPRPand TI Team subsequently discussed the comments and replies in a conference call orWorking Meeting.SSHAC Process ReviewNUREG-2117 describes the goal of a SSHAC process as being "to carry out properlyand document completely the activities of evaluation and integration, defined as:Evaluation:

The consideration of the complete set of data, models and methodsproposed by the larger technical community that are relevant to the hazardanalysis.

Inteqration:

Representing the center, body, and range of technically defensible interpretations in light of the evaluation process (i.e., informed by the assessment of existing data, models, and methods)."

During the Evaluation activities, the TI Team considered new data, models and methodsthat have been introduced within the technical community since the previous seismichazard studies were conducted for nuclear power plants in California and Arizona.

TheTeam evaluated newly available ground motion databases, ground motion prediction equations (GMPEs),

and ground motion simulation techniques.

Notably, the TI Teamevaluated methods for the representation of non-Gaussian aleatory variability, as wellas newly available methods for the visualization and characterization of epistemic uncertainty in ground motion prediction.

The PPRP finds that the T1 Team's evaluation was consistent with the expectations fora SSHAC Level 3 study, and, apart from the specific reservation noted at the end of thissection, was adequately documented.

The Integration phase entails thoroughly documenting the technical bases for allelements of the GMC model, to provide assurance that the center, body and range oftechnically defensible interpretations have been captured.

The TI Team used a newstatistical technique to generate a suite of representative models for median groundmotion prediction that collectively represent the epistemic uncertainty in ground motionmore broadly than do the published GMPEs alone. This technique is combined wit anew method to select and weight the predictions of the expanded suite of models. TheTI Team's method for assigning weights is based on consideration of appropriate data87 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3sets and numerical simulations, with adequate justification.

The TI Team's model foraleatory variability and weighting of alternative aleatory models is also adequately justified.

The PPRP finds that the TI Team's GMC model integration is consistent with theexpectations of a SSHAC Level 3 project, and, apart from the specific reservation notedin the next paragraph, was adequately documented.

The PPRP's reservation with respect to the documentation of the evaluation andintegration phases of the study is based on the TI Team's inability to produce a finalreport based on the last set of comments from the Panel (Submittal No. 3, February 20,2015) that were intended to improve the completeness and clarity of the documentation.

The TI Team was unable to revise the report in time for this letter to be issued in orderto meet contractual obligations to provide written documentation to the utilities.

The TITeam did provide written responses to the Panel's comments and assured the Panel inwriting that the final version of the report would take these comments into accountSSHAC Technical ReviewNUREG-2117 describes the PPRP's technical review role as follows:"The PPRP fulfills two parallel roles, the first being technical review. Thismeans that the PPRP is charged with ensuring that the full range of data,models, and methods have been duly considered in the assessment andalso that all technical decisions are adequately justified and documented.

The responsibility of the PPRP is to provide dear and timely feedback to theTIITFI and project manager to ensure that any technical or process deficiencies are identified at the earliest possible stage so that they can be corrected.

Morecommonly, the PPRP provides its perspectives and advice regarding the mannerin which ongoing activities can be improved or carried out more effectively.

Interms of technical review, a key responsibility of the PPRP is to highlight anydata, models or proponents that have not been considered.

Beyondcompleteness, it is not within the remnt of the PPRP to judge the weighting of thelogic-trees in detail but rather to judge the justification provided for the modelsincluded or exduded, and for the weights applied to the logic-tree branches."

As summarized in the table above, the PPRP reviewed the TI Team's evaluations ofdata, models and methods on multiple occasions, and through various means, including written communications, in-person

meetings, teleconferences, and review of the projectreport- The Panel was given adequate opportunity to question the TI Team concerning details of their analysis, and provided feedback verbally and in writing.

The TI Teamwas responsive to the technical input from the Panel. The TI Team's responses induded evaluating additional data sets suggested by the Panel, undertaking additional 88 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3analyses to address specific Panel technical questions or concerns, and examining andassessing alternative technical approaches suggested by the Panel.The PPRP therefore concludes that it has been afforded an adequate basis for technical assessment of the TI Team's evaluations and model integration and finds that theproject meets technical expectations for a SSHAC Level 3 study.Conclusion On the basis of its review of the SWUS GMC project, the PPRP finds that the projectmeets, with respect to both process and technical standards, the expectations for aSSHAC Level 3 study, with the reservation cited above. That reservation relates only tocompleteness of the documentation, which the TI Team has assured in writing will berectified in the final report.Sincerely, Steven M. DayChair, PPRPBrian ChiouMember, PPRPKenneth W. CampbellMember, PPRPCOmteO&QQ Thomas K. RockwellMember, PPRP89 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Appendix D SWUS GMC Project Transmittal LetterThis appendix provides the SWUS GMC Project letter Transmittal ofSWUS GMC SSHAC Level 3Technical Report (Rev. 2) from GeoPentech.

GeoPentech SWUS GMC SSHAC Level 3 Project Project No.12024B March 10, 2015Arizona Public Senrice CompanyPalo Verde Nuclear Generating Station (PVNGS)Mr. Chflstop her J WendellSenior Consulting "Chief' Civl Phone: (623) 393-6741E-mail: christopher.andeltlaps.com Pacific Gas and Electric CompanyDiablo Canyon Power Plant (DCPP)Mr. Kent Fore'Manager Geosciences Phone: (415) 973-5291E-mail: KSFl pge.com

Subject:

Transmittal of SWUS GMC SSHAC Level 3Technical Repott (Rev. 2)

Dear Messr. Fene' and Wandell:

This transmittal contains the Technical Report developed within the framework of theSouthwestem U.S. Ground Motion Characterization (SWUS GMC) Senior Seismic HazardAnalysis (SSHAC) Level 3 Project, for application to the Diablo Canyon Power Plant (DCPP)and Palo Verde Nuclear Generating Station (PVNGS) sites. The version of the Technical Reportis Rev. 2 and has today's date.This report documents the Final GMC Models for the median and the standard deviation.

In thisversion of the report; the Technical Integrator (TI) Team has fully addressed the last set ofcomments received from the Participatory Peer Review Panel (PPRP) on February 20, 2015,with the scope of improving the documentation completeness and clarity.This report contains a Rev. 2 of the Hazard Input Document (HID) model for DCPP, and a Rev.2 of the Hazard Input Document (HiD) model for PVNGS.525 K- Carlo Part ODtre. SuMB 2M0! Santa Ant Caltmsa 927otPlcew (714) 769"100 Fax (7143 769"191 WO SWe: rra-gRcpEntecf&OOM 90 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Arizoam Abic Service wad Pacific C-as and Electic CompanySWUS GMC Tec.mical Reaprt- Rev. 2Math10, 2015Page 2The final GMC Models for application to DCPP and PVNGS did not change iith respect to theRev. I Technical Report. Specifically, in the current Rev- 2 Technical Report the HID (Rev. 2)model for PVNGS is identical to the HID (Rev. 2) model for PVNGS included in the Rev. ITechnical Report Also, the HID (Rev. 2) model for DCPP is identical to the HID (Rev. 1)model for DCPP included in the Rev. I Technical Report.If you have any question, or need more information, please do not hesitate to contact us. Onbehalf of the Technical Integration (TI) Team and the other SWUS GMC SSHAC Level 3Project participants, we thank Arizona Public Service and Pacific Gas and Electric Company forthe support and cooperation.

Sincerefrc GeoPentech Carola Di Alessandro Project ManagerJohn A. BamneichPrincipal CC:PVNGS Project Technical Integrator Robin McGuirePVNGS Hazard Anal)ysts:

Melamie Walling and Gabriel ToroPVNGS SSC SSHAC Level 3 Project Manager Ross HartlebSWUS GMC TI Team Lead- Norm Abrahamson

.GeoPentech M I1. lel5; StUS GMC T"chdncl Repr. En-. 291 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Appendix E GMC PPRP Endorsement Letter Revision 2This appendix provides the March 10, 2015, Participatory Peer Review Panel Closure Letter.March 10, 2015Dr. Carola Di Alessandro SWUS Project ManagerGeoPentech, Inc.525 N. Cabrillo Park Drive, Suite 280Santa Ana, CA 92701

Subject:

Participatory Peer Review Panel Closure Letter, Southwest United StatesGround Motion Characterization Level 3 SSHAC Project

Dear Dr. Di Alessandro:

The Participatory Peer Review Panel (PPRP, also referred to herein as the 'Panel')

forthe Southwest United States (SWUS) Ground Motion Characterization (GMC) Project ispleased to issue this PPRP Closure Letter. Herein we describe our participation in theSWUS GMC SSHAC Level 3 project and present our findings.

Pursuant to theguidelines for a SSHAC Level 3 study (NUREG/CR-6372; NUREG-21 17), the PPRPwas engaged at all stages of the project, including review of the final Project Plan,Workshop agendas and participant lists; the planning of the evaluation and modelintegration activities; and review of the project documentation.

Throughout the project,the Panel reviewed and provided regular feedback on both the process followed, andthe technical assessments made, by the Technical Integrator (TI) Team. By this letterthe Panel documents the activities it has performed in the course of its review, itsassessment of the process followed relative to SSHAC Level 3 expectations, and itsassessment of the technical rationale underlying the GMC model.The PPRP issued a previous letter dated February 24, 2015. In that letter, the Panelnoted that there were limitations in the completeness and clarity of the projectdocumentation.

Those limitations were noted as exceptions to the Panel's finding thatthe project successfully met SSHAC Level 3 expectations.

Since that time, the TI Teamhas produced a final report, designated Rev2, addressing the final set of commentsfrom the Panel (PPRP Submittal No. 3, February 20,2015).

The Panel has reviewedRev2 (including a short addendum supplied to the PPRP in draft form on March 9 whichthe TI Team has assured in writing will be incorporated in the final version) and findsthat all material concerns have been adequately addressed and are now closed, apartfrom one remaining exception that will be described at the end of the SSHAC ProcessReview section below. Two GMC models were developed for application to DiabloCanyon Power Plant (DCPP) and Palo Verde Nuclear Generating Station (PVNGS),respectively.

The exception applies only to the GMC model for DCPP, and is notrelevant to the case of PVNGS.92 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3PPRP Activities in Support of the SWUS GMC ReviewIn a SSHAC Level 3 study, the PPRP fulfills two roles. The first is that of technical review, in which the Panel ensures that the full range of data, models and methods areconsidered and that technical decisions and judgments are adequately justified anddocumented.

The second is that of process review, under which the Panel ensures thatthe study maintains conformity with the SSHAC Level 3 guidelines.

To fulfill these roles,the Panel requires adequate opportunities to gain understanding of the data being used,the analyses being performed, the TI Team's evaluations of data and models, and thetechnical justifications for the TI Team's model decisions.

The table below summarizes the formal project acdivities in which the Panel participated.

Fulfilling these roles alsorequires the Panel to provide regular feedback to the TI Team during the course of theproject.

In addition to verbal feedback during Working Meetings and Workshops, thePanel provided written comments and recommendations at key stages of the project.Those written submittals are also noted in the table.Date PPRP Activityune 21, 2012 orking Meeting #1 (Planning).

Al PPRP members attended.

July 18, 2012 orking Meeting #2 (Planning).

All PPRP members attended.

.ugust 27, 2012 ck-off Meeting.

All PPRP members attended.

September 17, 2012 PRP submittal of written comments on the Project Plan.ctober 8, 2012 Working Meeting #3. PPRP representatives attended as observers.

-ovember 3, 2012 PPRP submittal of written comments on revised Project Plan.ovember 29, 2012 PPRP submittal of PPRP endorsement letter for Project Plan.ecember 10, 2012 Working Meeting #4. PPRP representatives attended as observers.

ebruary 11, 2013 Working Meeting #5. PPRP representatives attended as observers.

ararch 19-21,2013 Workshop

1. 1: Critical issues and Data Needs. All PPRP members attended asservers.

The PPRP provided verbal feedback to the T] Team at the end ofe:ch day of the Workchoppril 12, 2013 'orking Meeting #6. PPRP representatives attended as observers.

pnl 21,2013 PRP submittal of written comments on Workshop

1. 1.ay 23,.2013 orking Meeting #7. PPRP representatives attended as observers.

une 24, 2013 orking Meeting #8. PPRP representatives attended as observers.

uly 16.2013 orking Meeting #9. PPRP representatives attended as observers.

ugust 21, 2013 orking Meeting #10. PPRP representatives attended as observers.

ctober 2, 2013 orking Meeting #11. PPRP representatives attended as observers.

ctober 15, 2013 orking Meeting #12- PPRP representatives attended as observers.

October 22-24, 2013 Workshop

1. 2: Proponent Models and Alternative Interpretations.

All PPRPMembers attended as observers The PPRP provided verbal feedback to the T]ream at the end of each day of the Workshop.

ovember 26, 2013 orking Meeting #13. PPRP representatives attended as observers.

ecember 3, 2013 PRP submittal of written comments on Workshop

1. 2.anuary 2, 2014 Meeting #14. PPRP representatives attended as observers.

anuary 28-29, 2014 Cpecial Working Meeting.

All PPRP members attended as observers.

arch 3, 2014 orking Meeting #15. PPRP representatives attended as observers.

arch 10-12, 2014 Corkshop

1. 3: Preliminary GMC Models and Hazard Feedback.

All PPRPmbers attended as participants.

The PPRP provided verbal feedback to then Team at the end of each day of the Workshop.

March 24.,2014 orking Meeting #16. PPRP representatives attended as observers.

April 21, 2014 1PRP submittal of written comments on Workshop

1. 3.293 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units L1 2. and 3May 14, 2014 PRP Closure Pre-Briefing.

Al] PPRP members attended as participants.

July 17-18, 2014 PRP Closure Briefing.

All PPRP members attended as participants.

December 13, 2014 ubmittal No. 1 of PPRP written review comments on SWUS GMC Report:oomments on SWUS GMC Report Rev.0, Chapters 7, 10, 11, 12, 13, and_.ppendoess L, M. N. and R.December 16, 2014 leleconference, PPRP and TI Team, to discuss the PPRP written reviewcomments, Submittal No. 1.January 5, 2015 Submittal No. 2 of PPRP written review comments on SWUS GMC Report:Comments on SWUS GMC Report Rev.0, Chapters 6, 8, 91 14, and Appendices H, I. J, K. 0, and 0.January 7, 2015 Teleconference, PPRP and TI Team, to discuss the PPRP written reviewcomments, Submittal No. 2January 26, 2015 Teleconference, PPRP and TI Team, to discuss the main modifications introduced in SWUS GMC Report Draft Rev.1.February 9,2015 eleconference, PPRP and Ti Team, to discuss observations from PPRP partialreview of SWUS GMC Report Draft Rev.1.February 16, 2015 eleconference, PPRP and Project Manager to discuss project completion schedule.

February 20, 2015 Submittal No. 3 of PPRP written review comments on SWUS GMC Report:Comments on SWUS GMC Report Draft Rev.1.February 24, 2015 ;ubmittal of Closure Letter based on Draft Rev.1The PPRP finds that the level of ongoing review it was able to undertake, and theopportunities afforded the PPRP to provide feedback to the TI Team, met theexpectations for a SSHAC Level 3 study. Interactions with the TI Team provided ampleopportunity for the Panel to gain an understanding of the technical bases for the TITeam's evaluations.

The Panel also was given adequate opportunity to query the TITeam, especially in Workshop

1. 3 and in the Pre-Closure Briefing and Closure Briefing, to assess the justification provided for their model decisions.

The TI Team providedwritten responses to each formal PPRP submittal, and in nearly every case the PPRPand TI Team subsequently discussed the comments and replies in a conference call orWorking Meeting.SSHAC Process ReviewNUREG-2117 describes the goal of a SSHAC process as being 'to carry out properlyand document completely the activities of evaluation and integration, defined as:Evaluation:

The consideration of the complete set of data, models and methodsproposed by the larger technical community that are relevant to the hazardanalysis.

Integration:

Representing the center, body, and range of technically defensible interpretations in light of the evaluation process (i.e., informed by the assessment of existing data, models, and methods)."

During the Evaluation activities, the TI Team considered new data, models and methodsthat have been introduced within the technical community since the previous seismichazard studies were conducted for nuclear power plants in California and Arizona.

The394 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3Team evaluated newly available ground motion databases, ground motion prediction equations (GMPEs),

and ground motion simulation techniques.

Notably, the TI Teamevaluated methods for the representation of non-Gaussian aleatory variability, as wellas newly available methods-for the visualization and characterization of epistemic uncertainty in ground motion prediction.

The PPRP finds that the TI Team's evaluation and the documentation thereof areconsistent with the expectations for a SSHAC Level 3 study, apart from the specificreservation noted at the end of this section.The Integration phase entails thoroughly documenting the technical bases for allelements of the GMC model, to provide assurance that the center, body and range oftechnically defensible interpretations have been captured.

The TI Team used a newstatistical technique to generate a suite of representative models for median groundmotion prediction that collectively represent the epistemic uncertainty in ground motionmore broadly than do the published GMPEs alone. This technique is combined with anew method to select and weight the predictions of the expanded suite of models. TheTI Team's method for assigning weights is based on consideration of appropriate datasets and numerical simulations, with adequate justification.

The TI Team's model foraleatory variability and weighting of alternative aleatory models is also adequately justified.

The PPRP finds that the TI Team's GMC model integration and the documentation thereof are consistent with the expectations of a SSHAC Level 3 project apart from thespecific reservation noted in the next paragraph.

The Panel finds that the TI Team's evaluation of directivity models has limitations.

TheTI Team make use of a simplified directivity model to save computational time, and thefinal report adequately describes that model, how it is used, and some of its limitations.

However, because the simplified model is unpublished, it is also necessary for the TITeam to document that the simplified model is appropriate for the purpose for which it isapplied, in the sense that it gives results that are essentially consistent with thepublished and peer-reviewed model that it is intended to approximate.

The final report(in the March 9 addendum) documents the performance of the simplified model throughcomparison with results from a hazard calculation that uses the full, published directivity model. At hazard levels of 104 and above, the full model calculation confirms theconclusion obtained using the simplified model. At hazard levels below 10a4, however,the difference in calculated hazard between the full model and the simplified modelincreases with decreasing hazard level. This increasing trend has not been satisfactorily explained, has not been explored beyond the single fault case provided in the March 9addendum, and has not been quantified in terms of impact on equal-hazard spectra athazard levels of 10"( and lower. Because the key rationale for the zero weighting of thedirectivity branch in the GMC model for periods longer than 0.5 s (the period rangewhere the directivity effect applies) is the weak sensitivity of hazard to the directivity effect calculated using the simplified model, the PPRP finds that this weighting lackssufficient technical justification.

495 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3SSHAC Technical ReviewNUREG-2117 describes the PPRP's technical review role as follows:'The PPRP fulfills two parallel roles, the first being technical review. Thismeans that the PPRP is charged with ensuring that the full range of data,models, and methods have been duly considered in the assessment andalso that all technical decisions are adequately justified and documented.

The responsibility of the PPRP is to provide clear and timely feedback to theTIITFI and project manager to ensure that any technical or process deficiencies are identified at the earliest possible stage so that they can be corrected.

Morecommonly, the PPRP provides its perspectives and advice regarding the mannerin which ongoing activities can be improved or carried out more effectively.

Interms of technical review, a key responsibility of the PPRP is to highlight anydata, models or proponents that have not been considered.

Beyondcompleteness, it is not within the remit of the PPRP to judge the weighting of thelogic-trees in detail but rather to judge the justification provided for the modelsincluded or excluded, and for the weights applied to the logic-tree branches."

As summarized in the table above, the PPRP reviewed the TI Team's evaluations ofdata, models and methods on multiple occasions, and through various means, including written communications, in-person

meetings, teleconferences, and review of the projectreport. The Panel was given adequate opportunity to question the TI Team concerning details of their analysis, and provided feedback verbally and in writing.

The TI Teamwas responsive to the technical input from the Panel. The TI Team's responses included evaluating additional data sets suggested by the Panel, undertaking additional analyses to address specific Panel technical questions or concerns, and examining andassessing alternative technical approaches suggested by the Panel.The PPRP therefore concludes that it has been afforded an adequate basis for technical assessment of the TI Team's evaluations and model integration.

As noted above in thefinal paragraph of the SSHAC Process Review section, the evaluation of directivity effects has been inadequate and may constitute a technical limitation of the study. Apartfrom that reservation, the PPRP finds that the project meets technical expectations for aSSHAC Level 3 study.Conclusion On the basis of its review of the SWUS GMC project the PPRP finds that the projectmeets, with respect to both process and technical standards, the expectations for a96 of 97 Enclosure Seismic Hazard and Screening Report for thePalo Verde Nuclear Generating Stations Units 1, 2, and 3SSHAC Level 3 study, with the reservation cited above. That reservation pertainsspecifically to application of the direclivity component of the GMC model to the DCPPsite.Sincerely, Steven M. DayChair, PPRPBrian ChiouMember, PPRPKwvuktt Li. CLm4QQ.Kenneth W. CampbellMember, PPRPThomas K. RockwellMember, PPRP97 of 97