ML24366A030

Regulatory Audit in Support of License Request for Proposed Changes to the License and Technical Specifications to Facilitate Service Water Piping Repair

ML24366A030
Person / Time
Site:	Surry
Issue date:	01/13/2025
From:	Klos L Plant Licensing Branch II
To:	Carr E Virginia Electric & Power Co (VEPCO)
Klos, J
References
EPID L-2024-LLA-0118
Download: ML24366A030 (12)

Text

January 13, 2025 Eric S. Carr President - Nuclear Operations and Chief Nuclear Officer Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711

SUBJECT:

SURRY POWER STATION, UNIT NOS. 1 AND 2 - REGULATORY AUDIT IN SUPPORT OF LICENSE REQUEST FOR PROPOSED CHANGES TO THE LICENSE AND TECHNICAL SPECIFICATIONS TO FACILITATE SERVICE WATER PIPING REPAIR (EPID L-2024-LLA-0118)

Dear Eric S. Carr:

By letter dated September 3, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24248A171, Virginia Electric and Power Company (Dominion Energy Virginia) submitted a request to amend the license and technical specifications for Surry Power Station (Surry), Units 1 and 2, Subsequent Renewed Facility Operating License No. DPR-32 and DPR-37, respectively. The proposed amendments would establish the requirements for, and the use of a temporary canal level probe and temporary supply line (jumper) to provide service water (SW) to the component cooling heat exchangers (CCHXs) and facilitate planned maintenance activities (i.e., cleaning, inspection, repair (as needed) of the existing SW piping. The licensee proposes to install a carbon fiber reinforced polymer (CFRP) system on the existing concrete-encased SW supply piping to the CCHXs. These activities are proposed for a 35-day period during the refueling outage.

The U.S. Nuclear Regulatory Commission (NRC) staff has identified the need for a regulatory audit to examine the Dominion Energy Virginias non-docketed information with the intent to gain understanding, to verify information, or to identify information that will require docketing to support the basis of the licensing or regulatory decision.

The NRC staff will conduct the audit virtually via Microsoft (MS)Teams and in-person, as needed, based on coordination between the NRC licensing Project Manager, John Klos and the licensee. The audits virtual portion will utilize a licensee-established electronic portal available to NRC staff for approximately one month between February 1 to March 15, 2025, with formal audit meetings to be scheduled during this period, via MS Teams, or in-person, as needed.

If you have any questions, please contact me by telephone at 301-415-5136 or by email to John.Klos@nrc.gov.

Sincerely,

/RA/

L. John Klos, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-280 and 50-281

Enclosure:

Audit Plan cc: Listserv

Enclosure REGULATORY AUDIT PLAN BY THE OFFICE OF NUCLEAR REACTOR REGULATION TO SUPPORT THE REVIEW OF LICENSE REQUEST FOR PROPOSED CHANGES TO THE LICENSE AND TECHNICAL SPECIFICATIONS TO FACILITATE SERVICE WATER PIPING REPAIR DOMINION ENERGY VIRGINIA SURRY POWER STATION, UNITS 1 AND 2 DOCKET NOS. 50-280 AND 50-281

1.0 BACKGROUND

By letter dated September 3, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24248A171, Virginia Electric and Power Company (Dominion Energy Virginia) submitted a request to amend the license and technical specifications for Surry Power Station (Surry), Units 1 and 2, Subsequent Renewed Facility Operating License No. DPR-32 and DPR-37, respectively. The proposed license amendment request (LAR) would establish the requirements for, and the use of a temporary canal level probe and temporary supply line (jumper) to provide service water (SW) to the component cooling heat exchangers (CCHXs) and facilitate planned maintenance activities (i.e., cleaning, inspection, repair (as needed) of the existing SW piping. The licensee proposes to install a carbon fiber reinforced polymer (CFRP) system on the concrete-encased SW supply piping to the CCHXs. These activities are proposed for a 35-day period during the refueling outage.

The staff from the Nuclear Regulatory Commissions(NRCs) Office of Nuclear Reactor Regulation(NRR) has initiated its review of the LAR in accordance with NRR Office Instruction LIC-101, License Amendment Review Procedures (ML19248C539).

2.0 REGULATORY AUDIT BASES A regulatory audit is a planned license, or regulation-related activity that includes the examination and evaluation of Dominion Energy Virginias non-docketed information that provides the technical basis for the LAR. An audit is conducted to gain understanding, to verify information, and to identify information that will require docketing to support the basis of a licensing or regulatory decision. An audit will assist the NRC staff in efficiently conducting its review and gaining insights to the licensees processes and procedures. Information that the NRC staff relies upon to make the safety determination must be submitted on the docket. This audit will be conducted in accordance with NRR LIC-111, Regulatory Audits, (Revision 2) with exceptions noted within this audit plan (ML24309A281)

The NRC staff will perform the audit to support its evaluation of whether the licensees requests can be approved per Title 10 of The Code of Federal Regulations (10 CFR) Section 50.90, Application for amendment of license, construction permit, or early site permit.

3.0 SCOPE The audit team will view the documentation and calculations that provide the technical support for the LAR to:

Gain a better understanding of the detailed calculations, analyses, and bases underlying the LARs and confirm the NRC staffs understanding of the request.

Gain a better understanding of plant design features and implications for the LAR request.

Identify any information needed to enable the NRC staffs evaluation of whether the proposed changes challenge design-basis functions or adversely affect the capability or capacity of plant equipment to perform design-basis functions.

Identify questions and requests that may become formal requests for additional information (RAI) per NRR Office Instruction LIC-115, Processing Requests for Additional Information (ML21141A238).

The scope of the NRC staffs audit will focus on the following subjects:

3.1 The Contingency Action Plan (CAP)

A review of the CAP to consider all elements that document and describe a comprehensive and complete plan.

1. The LAR, Attachment 1, page 12, states in part, that Use of the jumper will be limited to conditions when the maximum SW supply temperature is at or below 80°F.

a. Please identify how the CAP would be utilized (entry steps and phase), if an 80°F supply temperature was exceeded, or being approached, while the temporary SW piping is in service?

b. Is there margin above 80°F for continued operation of the temporary safety-related, seismic SW piping?

c. What is the likelihood, based on seasonal cooling and meteorological data, that 80°F will not be exceeded during the 35-day period if no margin above 80°F is available?

d. Please provide the ultimate heat sink temperature limit to be utilized during the CAP, the normal operating temperatures, and the faulted temperatures for the subject temporary SW piping.

2. What is the CAPs Phase I, Evacuation, specific allocated time period that accounts for the existing SW pipings debris and personnel removal, in any and all case conditions, prior to the restoration of a normal SW flow path (CAP, Phase III, Reflood) necessitated, for example, by a Spent Fuel Pool (SFP) failure, or hurricane warning (where Phase III Reflood, is now activated)?

a. How can, and by what means, will that time CAP Phase I, Evacuation, period of clean up, etc., be verified and be accounted for as a fixed value?

3. The LAR, Attachment 1, page 21, states, in part, that within Unit 1s refueling schedule three general Reactor Coolant System conditions exist -- concurrent with the use of the temporary SW jumper - and that Condition 2 is the most limiting.

a. Please describe the engineering assumptions and conditions which may cause the loops to have to be isolated and indicated Condition 2 as the most limiting?

4. The LAR, Attachment 1, page 20, states, in part that:

An internally developed QA software was utilized to calculate heat-up times of the SFP. This software was originally developed in response to the post-Fukushima INPO recommendations which call for a method of determining the time for the bulk temperature in the SFP to reach 200°F in the event that all coolant systems were lost for an extended period of time. This software fundamentally uses a best estimate methodology and has been benchmarked to actual measured data at SPS [Surry Power Station] where SFP cooling was turned off. To ensure the overall conservatism of this analysis, bounding inputs were used.

a. Please provide the calculation and identify the parameters, inputs, outputs, and engineering assumptions associated with this analysis.

Please also identify any previous NRC review and evaluation of this software and the associated calculation methodology.

5. The LAR, Attachment 1, page 20, states, in part, that:

The epoxy requires 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to achieve an 85% cure, which is an industry consensus standard used as a threshold for returning a pipe to service that should not result in a detrimental effect on the CFRP liner.

Page 20, also states, while discussing SFP heat up time periods and temperaturesFurther testing may be utilized to justify a lower percentage cure that precludes adverse impacts to the CCHX function to support restoration as deemed necessary.

Additionally, Page 20, states, that In the event the normal SW flow path is required to be restored and is used as the primary flow path to the CCHXs, additional inspection of the CFRP liner would be required to ensure the installation was not adversely impacted. Evaluation against the alternative request for the use of CFRP would be required to ensure the as-left repair is acceptable to continue with the installation, or if additional regulatory relief would be required.

Based on the annotated excerpts above, it is not apparent how the CAP plan and CFRP completion inspections would be accomplished. Please clarify the conflicting conditions that may be the cause for lower cure rates and times.

a. Please provide a detailed discussion concerning the performance testing associated with a lower percentage cure rate and how that would also preclude adverse impacts to the CCHX function and normal SW restoration. Please also discuss performance testing availability within the CAP program.

6. A CAP description/plan/procedure which includes all case conditions where the CFRP application may be partially complete at less than cure point, or at less than the entire length of the repair piping. This description/plan/procedure should also state any and all necessary, supportive actions that shall be applied to ensure structural integrity of SW piping.

Please describe the following:

a. The sampling/inspection and time-period allocations that may be necessary to obtain cure level verification, such as, during a CAP exigent action conditions (Phase III, Reflood, activation with a hurricane warning).

b. Where CFRP installation is less than or at the cure point, what is the steps for assurance of adequate curing to withstand hydraulic and other structural related loading. The discuss should consider that adequate curing provides reasonable assurance that CFRP layer(s) do not debond and peel off, and/or the CFRP laminate does not debond from the metal substrate, creating foreign material to block flow.

c. The 12-hour duration for achieving 85% degree of cure for epoxy is the manufacturers specified time to cure epoxy. The NRC notes that the CFRP composite material and repair are not the same ASME Code-approved for nuclear applications. Please provide a discussion on laboratory and field testing to be performed to ensure the epoxy is achieved the required degree of curing as part of the CAP.

d. Provide a discussion on the final curing process of partially installed and incomplete CFRP repair applicable to all CAP phases. Please include discussion on the field or pipe interior temperature during CFRP installation, field curing temperature along the pipe length, and determination/verification of field glass transition temperatures. Also, please discuss how the field glass transition temperature and 85%

degree cure for the partially installed CFRP composite ensures consistency with the CFRP design requirements.

Further, the NRC staff notes, that a comprehensive CAP plan would include a CFRP installation inclusive of an adequate glass transition temperature, at various temperatures, to demonstrate the epoxy behavior at the maximum SW system piping temperature. Please discuss how the CAP plan allows for appropriate actions and time periods to complete these aspects during all phases of the CAP plan.

3.2 The Temporary SW Piping For the temporary safety related, seismic SW piping, please provide

1. The piping stress and seismic analysis model/calculation which identifies and documents the load cases (deadweight, thermal, and seismic, wind and other applicable load cases), boundary conditions, and the input loading analyzed over those load cases.

Please provide calculations regarding:

a. seismic conditions/data point that was analyzed for the piping,

b. any load combinations that were applied,

c. the engineering codes utilized,

d. any acceptance criteria applied with its associated engineering standards

e. design margins that were analyzed for the temporary SW pipe, and

f.

how the calculations analysis conditions meet, and are bounding at the level at which the SW temporary piping is removed from service and restoration of the normal SW flow occurs within the CAP.

2. Drawings that document the seismic restraint, piping hanger arrangement supportive of and contingent to the piping stress and seismic analysis model/calculation in Item No. 1 above. Provide the option for a walkdown, as needed, of the Turbine Building basement floor and the restraint/hangar intended configuration post review of the supplied drawings/isometric.

3. The pipes support (existing and new) design calculations.

3.3 Seismic Risk Insights For the LARs seismic risk assessment, please provide:

1. A description of the engineering assumptions and documentation that qualitatively supports this LARs statement that The SPRA [seismic probabilistic risk assessment] quantification concluded that no severe accident vulnerabilities exist at SPS from a potential seismic event. Hence, the proposed change has a negligible impact on seismic risk and is screened from further evaluation (Attachment 1, page 38), excluding the existing quantification within Surrys probabilistic risk assessment. Describe how the qualitative description fully envelopes all the LARs equipment/components involved either temporarily or fixed, inclusive of the CAP Phases.

3.4 Missile Protection Insights

1. Please provide a comprehensive list and a drawing of the TB equipment (components, piping etc.) which will be credited as missile protection for the temporary safety-related, seismic SW piping.

2. Please provide documentation, description, and the engineering assumptions for the equipment, piping steel structure, grating, and the 9-inch slab that is intended to provide missile interface to the temporary safety-related, seismic SW piping. Provide information documenting the amount and level of energy absorption this interfacing equipment would be expected to absorb.

3.5 Licensing basis for Tornado activity wind speeds, TMRE and SW flooding hazard In Attachment 1, page 15, states that tornado activity conditions and characteristics regarding Surry County, Virginia from 1950 to 1995 were supplied and supportive of two previous, SW precedent amendments (Amendment Nos. 279 and 279, dated September 23, 2013 (ML13231A170). The LAR also states that tornado conditions -- based on information obtained from the National Centers for Environmental Information (Storm Events) -- produce the most penetrating missile equivalent to a wooden utility pole, vertically or horizontal at 150 mph (per UFSAR Sec. 15.2.3 [as confirmed in latest version of Surry UFSAR Rev. 55, ML23275A077, February 2024]. In its submittal, the licensee states that the frequency of SW pipe flood due to failure of the piping from a postulated tornado missile was estimated using guidance from NEI

[Nuclear Energy Institute] 17-02, Tornado Missile Risk Evaluator (TMRE) Industry Guidance Document, (LAR Reference 7.5, ML17268A023). The NRC staff notes that amendments for three pilot plants were approved using the methodology in NEI-17-02 but that each pilot was different, and NEI did not ultimately pursue NRC endorsement of Revision 1.

Alternatively, Surrys Amendment Nos. 316 and 316 (ML23312A192), Risk Informed Approach for Tornado Classification of the Fuel Handling Trolley Support Structure, (EPID L-2022-LLA-0068), and Section 3.1.1, Evaluation of Tornado Winds Speed, of the NRC safety evaluation noted that the licensees docketed letter dated May 11, 2022 (ML22131A351),

acknowledged that the licensee calculated tornado initiating event frequencies using insights from the Harris TMRE pilot that used data from NUREG/CR-4461, ML070810400, Table 6-1, Tornado Wind Speed Estimates for United States Nuclear Power Plant Sites, associated with the Fujita tornado wind speed vs. the enhanced Fujita scale level. The NRC staffs review of that docketed information supporting Amendments Nos. 316 and 316 stated, in part, that the licensees calculation of the site-specific hazard curve acceptable because (1) the licensee used the appropriate site-specific data from RG 1.76 and NUREG/CR-4461; (2) the licensee used the more conservative original Fujita scale; and (3) the licensees calculation utilizes NEI 17-02, Revision 1B, dated September 19, 2018, which is incorporated by reference into the licensees UFSAR and the current licensing basis (CLB) serves as an update to NEI 17-02, Revision 1, reflective of a Surry site-specific TMRE methodology.

Please justify why:

1. The PRA statements made in this LAR for the probabilistic risk associated with TMRE assessment related to tornado activity and the risk of SW piping flooding (utilizing NEI 17-02, TMRE, Rev. 1, 2017), appear to use an earlier version of the NEI guidance as compared to the docketed information supporting Amendment Nos. 316 and 316 and the current licensing basis regarding wind/tornado assessment and a site-specific use of TMRE (utilizing NEI 17-02, Revision 1B, 2018).

3.5 Controls on the Movement of Heavy Loads

1. The NRC staff requests the licensee to discuss the drop scenarios mitigated via its LAR/CAP movement control of heavy loads program and to identify any additional SSCs in the drop area that could impact SW recovery efforts should such a heavy loads drop-event occur.

2. The LARs attachment 1, page 27, states that restricted area maps will be developed to control heavy load lifts whenever the SW jumper is in service, in lieu of safe load paths. Please provide these maps in the electronic portal for review and teleconference discussion concerning the maps, their development and criteria.

4.0 INFORMATION AND OTHER MATERIAL NECESSARY FOR THE REGULATORY AUDIT The NRC staff will request information throughout the audit period. The NRC staff will identify the information to be audited (e.g., methodology, process information, and calculations) and the subjects of requested meetings.

The NRC staff requests the licensee to collect and have the information identified above available and accessible for the NRC staffs review via a web-based electronic portal by the intended start date of the audit, or earlier. The NRC staff requests that any supplemental information requested be available and accessible for the NRC staffs review within approximately one week of the date of the NRCs notification to the licensee of the new requests. The NRC staff requests the licensee to notify the review team when the audit item is added to its electronic portal by sending an email to the NRC licensing project manager.

The NRC staff acknowledges and will observe appropriate handling and protection of proprietary information made available for the audit. Any information accessed through the licensees portal will not be held or retained in any way by NRC staff.

5.0 AUDIT TEAM The following table identifies the NRC audit team members, including contractors, and their respective focus areas:

Name E-mail Review Area (Organization)

John Klos John.Klos@nrc.gov Plant Licensing Branch LPL II-1 (LPL2-1)

David Nold David.Nold@nrc.gov Containment and Plant Systems Branch Raul Hernandez Raul.Hernandez@nrc.gov Containment and Plant Systems Branch Aaron Gallman Aaron.Gallman@nrc.gov Structural, Civil, and Geotechnical Engineering Branch Ata Istar Ata.Istar@nrc.gov Structural, Civil, and Geotechnical Engineering Branch Si Hwan Park SiHwan.Park@nrc.gov Structural, Civil, and Geotechnical Engineering Branch Chakrapani Basavaraju Chakrapani.Basavaraju@nrc.gov Mechanical Engineering and Inservice Testing Branch John Bozga John.Bozga@nrc.gov Mechanical Engineering and Inservice Testing Branch Ali Rezai Ali.Rezai@nrc.gov Piping and Head Penetrations Branch Thinh.Dinh Thinh.Dinh@nrc.gov Probabilistic Risk Assessment Licensing Branch B 6.0 LOGISTICS The audit will be conducted using a secure, online electronic portal, established by the licensee to present supporting documentation and calculations, by teleconferences with Dominion Energy Virginias subject matter experts, virtually, and with in-person meetings, as necessary.

The audit will begin within two weeks of the date of this audit plan (approximately February 1 to March 15, 2025). The NRC will establish a schedule of audit teleconferences/meetings on mutually agreeable dates and times to discuss information needs and questions arising from the NRCs review of the audited items. The NRCs licensing project manager will inform the licensee of audit meeting dates when they are established. Audit meeting agenda and questions will be sent in advance of the audit teleconferences.

7.0 SPECIAL REQUESTS The following conditions associated with the online web-based electronic portal should be maintained while the NRC staff on the audit team who have access to the online portal:

The online electronic portal will be password-protected, and separate passwords will be assigned to each member of the audit team.

The online web-based electronic portal will be sufficiently secure to prevent the NRC staff and contractors from printing, saving, downloading, or collecting any information from the web portal.

Conditions of use of the online electronic portal will be displayed on the login screen and will require acknowledgment by each user.

Dominion Energy Virginia is expected to provide username and password information directly to the NRC staff audit team, listed above. The NRC project manager will provide Dominion Energy Virginia the names and contact information if any NRC staff may need to be added to the audit team. All other communications should be coordinated with the NRC project manager. The NRCs project manager will inform the licensee via routine communications when the NRC staff no longer needs access to the electronic portal.

No data accessed by the audit team members will be retained by the NRC following the conclusion of the audit.

8.0 DELIVERABLES The NRC staff will develop any requests for additional information (RAI), as needed, in accordance with NRR LIC-115 and issue such RAI separate from audit-related correspondence.

The NRC staff will issue an audit summary report within approximately 90 days after the end of the audit and prior to completing its safety evaluation of the LAR.

ML24366A030 OFFICE NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1/LA NRR/DSS/SCPB/BC NAME JKlos KZeleznock MValentin DATE 12/30/2024 12/31/2024 and 01/14/2025 1/7/2025 OFFICE NRR/DEX/ESEB/BC NRR/DEX/EMIB/BC NRR/DNRL/NPHP/BC NAME ITseng TScarbrough for SBailey MMarkley DATE 1/8/2025 1/6/2025 1/7/2025 OFFICE NRR/DRA/APLB NRR/DORL/LPL2-1/BC NRR/DORL/LPL2-1/PM NAME EDavidson MMarkley JKlos DATE 1/8/2025 1/13/2025 1/13/2025