ML20151X466
| ML20151X466 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon, 05000000 |
| Issue date: | 12/07/1967 |
| From: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Palladino N Advisory Committee on Reactor Safeguards |
| Shared Package | |
| ML20151W779 | List:
|
| References | |
| FOIA-88-156 NUDOCS 8808250367 | |
| Download: ML20151X466 (1) | |
Text
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UNITED STATES
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ATOMIC ENERGY CLMMISSION
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20545 Dece:nter 7, lef7 Docket No. 50-275 Mr. Nunzio Palladino Chairman, Advisory Committee on Reactor Safeguards U. S. Atomic Energy Commission Washington, D. C.
Dear Mr. Palladino:
Transmitted for the review of the Connittee are tventy-four copies of the foll.owing:
PACIFIC GAS & ELEC'IRIC CO'2ANY DIABLO CAhTCH 1.
Letter dated recember 6,1967 transnitting kend:nent No. 9 W.tch includes Supplement No. 8 to the PSAR.
2.
Letter deted Neveder 30, 1967 transmitting Atendment No. 8 vhich includes Supplement No. 7 to the PSAR.
Sincerely yours, Peter A. Morris, Director Division of Reactor Licensing
Enclosures:
As stated above Distribution:
Suppl.
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Form AEC.318 (Rev.643>
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Decket No. 50 W 5 Dr. Nathan M. Neinmark 1114 Civil Engineering Building University 't Illinois Urbana, Illinois 61801
Dear Dr. Demark:
As you knew we are presently preparing our Safety Evaluation regarding Pacific Gr.s and Electric Contpaay's Diablo Canyon Nuclear Plant. An attachment to our evaluation will include your report on the Aiequacy of the Structural Criteria for the Diablo Canyon Site Nuclear Plant. We have placed your draft rept.rt of December ).967 in final form La per our telephone conversations.
If the report is acceptable to you, we wuld appreciate your signatura on one of the enclosed reports to be included in our rseerd files.
Sincerely yours, m
- s. n ye, 4.aistant Direeter for Reacter Projects Division of Reacgr Licensing Enclosure i
me sek me, ors dated 12/67 i
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CONSULTING Ei4GINEERING SERVICES 1114 CIVIL ENGINEERING BUILolNG v
URCANA ILLINOIS 618ol 22 January 1968 Dr. Peter A. Morris, Director Division of Reactor I.icensing U. S. Atomic Energy Commission Washington, D.C.
20545 Diablo Canyon Re. port - Docket No. 50-2h5 Re:
Dear Dr. Morris:
In accordance with the request f rom Roger S. Boyd, dated 16 January 1968, we have reviewed the report to the AEC Regulatory Staff dated December 1967, prepared by Dr. Hall and myself, and compared the copy with the draft prepared by us.
One mir.or point is called to your attention. At the bottom of the first paragraph on page 7, the original draf t and notes (f rom the end of the first complete paragraph on page 8 of the original d aft) indicates that a sentence should be added as follows:
"On this basis, we concur in the des ign approach adopted."
However, this added statement may not be important, and I believe that the typed copy of the report reflects our views and is in accord with our draf t.
Therefore I am signing it on page 11 and returning a copy to you.
I am also returning the amended draf t copy, which is marked for Troy Conner.
Thank you for your cooperat lon.
Sincerely yours.
DMA%c
't N. M. Newmark bjw cc:
W. J. Hall Enclosu re ver:n.:n y u
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REPORT TO AEC REGUIAT 2Y STAFF AIEQUACY OF BfE SSUCWRAL CRITERIA Fm THE DIABLO CANYW SITE NUCIE.AR PLANT Pacific Gas and Electric Company (Docket 50-275) by N. M. Newmark and W. J. Hall December, 1967 l
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ADPAUACY OF DIE CTRUCWRAL CRITERIA FOR THE DIABLO CANYON SITE PJCLEAR PLAIC by N. M. Newmark and W. J. Hall INTROIXJCTION This report concerns the adequacy of the containment structures and components, reactor piping and reactor internals, for the Diablo Canyon Site Nuclear Plant, for which application for a construction permit and operating license has been :nade to the U. S. Atomic Energy Cocnission (Ibchet No. 50-275) by the Pacific Gas and Electric Company. The facility is to be located in San Luis Obispo County, Oslifornia,12 miles vest southwest of the city of San Luis Obispo, and adjacent to the Pacific Ocean and Diablo Canyon Creek. Tne site is about 190 miles south of San Francisco and 150 miles northwest of Los Ac6eles.
Specifically this report is concerned with the evaluation of the design criteria that determine the ability of the containment system, piping and reactor internals to withstand a design earthquake acting simultaneously v.tv. other applicable loads foming the basis of the desi n.
The facility also 8
is to be designed to withstani a mavimum earthquake simultaneously with other applicable loads to the extent of insuring safe shutdown and containment. This report is based on information ani criteria set forth in the preliminary safety analysis report (PSAR) ani supplements thereto as listed at the eni of this report. We have participated in discussions with the AEC Regulatory Staff and the applicant and its consultants, in which many of the design criteria were discussed in detail.
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DESCRIPTION OF THE FACILITY The Diablo Canyon Nuclear Plant is described in the PSAR as a pressurized i
vater reactor nuclear steam supply system furnished by the Westinghouse Electric Corporation and designed for an initial power output of 3250 Wt (1060 We net).
The reactor cooling system consists of four closed reactor coolant loops connected in parallel to the reactor vessel, each provided with a reactor coolant pump and a steam generator. The reactor vessel vill have an inside diameter of about 14 5 ft., a height of 42 3 ft., vill operate with a design pressure of 2485 psig, a design temperature of 650 F, and is made of SA-302 grade B lov anoy steel internally clad with type 304 austenitic stainless steel.
The reactor containment structure which encloses the reactor and steam generators, consists of a steel lined concrete sheu in the form of a reinforced The concrete vertical cylinder with a flat base and hemispherical dome.
cylindrical structure of 140 ft. inside diameter has side valls rising 142 ft.
from the liner at the base to the spring line of the done. The concrete side valls of the cylinder and the dome vill be approximately 3 ft. 6 and 2 ft. 6 in.-
in thickness, respectively. The concrete reinforcing steel pattern is described from the conceptuauy in Supplement 1 and consists of bars oriented at 30 i
vertical in such a manner that the pattern does not require temination of any bars in the done. These diagonal bars are designed to carry both the lateral I
shear as ven as vertical tensile forces. In addition there is hoop reinforcing in the cylinirical portion of the structure. For resistance to radial shears the applicant proposes to use a system of vertical vide flange beams spaced four The beams are attached by hinge connections to the base slab feet on centers.
at the lower end and are teminated about 20 ft. above the top of the base slab.
The function of the beams is to provide resistance to the moments and shears l
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Q created by the discontinuity at the base and to provide a grsdual transition of load carrying elements between the base and the cylinder vall. These beams do not participate in resisting either uplift due to pressure or ahear and tension due to earthquake locding; these forces c e to be resisted by the diagonal steel reinforcing just described. The concrete van in this lover zone is divided into three zones. The inner r,one, about 1 ft, thick, consists of reinforced concrete and is the element to which the liner is attached. The middle zone contains the vertical steel I-beams which in turn act as supports for the 16 in.
thick reinforced concrete slab spanning the space between the beams. The outer zone consists of 6 bout 14 in, of concrete in which the dia6onal and hoop reinforcement are enbedded. The three zones are provided with bond-breaking material to insure that the elements vill act separately. The reinforcing steel for the dome, cylindrical valls and base mat vill te hi6h strength reinforcin6 conforming to the AS24 A432 speciff cation. The A432 reinforcing bars of size larger than No.11 are to be spliced with Cadweld splices except in cases where accessibility makes velding waniatory.
The liner, t.s described in Supplement 2, vin bin a minimm of 3/8 in.
thick for the de s and cylindrical valls and 1/4 in. thick for the base slab.
The anchor studs are to be L shaped and win be fusion velded to the liner plate.
The studs vin be spaced at the corners of a 20 in. square grid, and the design is intended to preclude major affects arising from buckling of the liner.
Personnel and equipment access hatches are provided for access to the containment vessel. In addition there are other penetrations for piping and electrical conduits.
The facility includes a sea water intake structure located at sea level i
at the base of the cliff vith circulating water conduits and euxiliary salt water l
conduits leadin6 to the nuclear plant.
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-4 The inforention on the geology at the site is described in the PSAR and the several supplements.
The bedrock at the site area is of tertiary age and comprises =arine shales, sandstone and fine-grained tuffacecus sediments, Mong with a considerable variety of tuffs of sulcarine volcanic origin.
All these ocks are firm and compact, and are exposed in the seaward edge of the terr ue on which the plant is to be built, which ranges in elevation from 60 to 100 ft. above sea level, and is approxicately 1,000 ft. vide. The bed ock is overlain by marine and non-marine deposits of Pleistocene ace. The major component; of the power plant are to be founded on bedrock in all cases. The site has been vell explored and there is no evidence of any significant fault offsets of recent origin.
The report by the consulting geologist on the project, Dr. Richard H. Jahns, presented as Appendix A of the third supplecent, concludes that the possibility of fenit-induced perennent ground displacement within the plant area during the useful life of the power plant is sufficiently remote to be safely disregarded.
SCURCES & STRESSES IN CONIAIIDEYf STRUCIURE AND TYPE I CCMPOKENTS The containment structure is to be designed for the following loadings:
dead load of the structure; live loads (including construction loads and equipment loads); internal pressure, due to a loss-of-coolant accident, of about 47 psig; test pressure of 54 psig; negative internal pressure of 3 5 Psig; stresses arising from thermal expansion; vind loading corresponding to the Uniform Duilding Code - 1964 edition and corresponding to 87 to 100 mph winds; andots*Jgnke loading as described next.
The earthquake loading vill be based on two separate earthquakes, which for the design earthquake condition correspond to mav4=w horizontal ground accelerations of 0.20g or 0.15g. The containment design also vill be reviewed i
for no loss of function using response spectra corresponding to earthquakes of I
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5 twice the maximum acceleration noted above, namely 0.40s and 0 30s, but with the latter earthquake having a maximum ground velocity corresponding roughly to a value of 0.40g ground acceleration. The U. S. Coast and Geodetic Survey i
report (Ref. 3) concurs in 0.20g and 0.40g values of maximum Sround acceleration for design and maximum conditions.
Class I piping and equipment, as discussed in Supplements 2 and 5, will be desi6ned for normal loads, (internal pressure, dead load, thermal expansion, etc. ) combined with pipe rupture loads and earthquale loading.
The reactor internals are to be desi6ned to resist earthquake combined with blow-down loadin6s and other applicable loadin6s.
CJMENTS ON ADEQUACY OF DESIGN Seismic Design For this facility the containment design is to be male for two earthquakes correspondiDg to maximam horizontal ground accetlerations of 0.20g (Earthquake D) and 0.15g (Earthquake B). For the==v4 - = earthquake loading the two earthquakes are characterized by horizontal ground accelerations of twice the values just cited, namely 0.40g and 0 30s. spectra corresponding to these earthquakes are presented as Figs. 2-11 through 2-14 of the PSAR and again in Supplement No. 3 beginning on page 22, along with an envelope of the spectra for the no. loss-of function condition (Fig. III. A.12-5, Supplement -3).
We concur with the response spectra for the earthquakes when they are used in the following manner.
Since the response spectrum values for Egrthquake D S ve values that i
control for hi h frequencies, and for Earthqueke B, values that control fcr 6
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. intemediate and lov frequencies, both earthquakes must be used and the maximum response in either must be considered to apply to the design or safe shut-down of single degree of freedom elements. This is permissible in view of the fact that Earthquake B gives response values for lov and intermediate frequencies that lie above the response spectrum values from TID 7024 when normalized to an acceleration of 0.40s. Hence this earthquake may be considered to correspond to a 0.40g earthquake for lov and intermediate frequencies.
However, for safe shut-down of multi-degree-of-freedom systems, we take the position that.the combined or envelope spectrum for the two earthquakes must be used in order to avoid a possible deficiency in the provision for safe shut-down. This envelope spectrum is consistent with an El Centro type response spectrum for a maximum ground acceleration of 0.40s.
With regard to the method of analysis of the containment structure, it is noted on page 2-29 of T,he PSAR that all modes having a period greater than 0.08 secs. vill be included in the analysis and that in addition for components or structures having multiple degrees of freedom, all significant modes, and in no case less than 3 modes, vill be considered. It is further stated that for single degree of freedom systems, the funaamantal mode of vibration vill be used in the analysis. The applicant has a6 reed however that for a single degree of freedom system, no matter what the period, vbether it is above or below 0.08 secs., the l
appropriate period and spectral v:celeration vill be employed in the design, and further that for multi 2 e degree of freedom systems all significant modes 1
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vill be considered.
On this basis, we concur with the approach.
The method of dynamic analysis is described in Sections 2 and 5 of the PSAR and a6ain in answer to Question III. A.15 of supplement 1.
It is noted l
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7 that the dynamic analysis to be followed for the Class I conponents and structures is the modal participation factor method. Further the modal analysis may be carried out either through the use directly of the smoothed spectra, or employing a time history of ground motion, employing earthquake records with amplitude values scaled which lead to essentially the same smoothed spectra. Diccussion of this point is presented by the applicant in answer to question III.A.13 in Supplement 3 We concur in the use of the moded participation method in the analysis and design, as well as the use of either the smoothed spectra or the time history input method, provided that the time history input yields the esme response spectra as given in the report without any major deviations below those smoothed response spectrum values The presented in the PSAR for the envelope of the two earthquakes considered.
applicant has advised that the time history input used in its analysis yields substantially the same response spectra as the envelope spectra of the two earthquakes considered.
Vertical acceleratior. talues in all cases vill be taken as two-thirds the correspondin6 maximum horizontal ground acceleration, and the effects of horizontal and vertical earthquake loadings vill be combined, and considered to act simultaneously. In addition in the elastic analysis, for the containment structure the usual fractional increase in stress for short tena loading vill not be used. We concur in these criteria.
The danping values to be used in the design are given on page 2-29 (revised 7-31-67) of the PSAR and we concur with the values given therein.
General Design Provisions for Containment We have reviewed the design stress criteria presented on page 5-9 of the PSAR and the load factor expressions to be employed in the design and find these reasonable. Further, we zete on pase 5-12 of the PSAR that no steel
8 reinforce-ent vill experience avera6e stress beyond the yield point at the factored load, and a statement on pase 5-13 that the liner vill be designed to assure that stresses vill not exceed the yield point at the factored loads.
Further amplification on these points is given in answer to Question III. A.5 of Supplement 2.
The applicant has confirmed our interpretation that the avera6e stress in the reinforcement and liners vill not exceed yield and that i
the defomations win be limited to that of general yielding under the mavimum earthquake loading conditions. On this basis, ve concur in this approach.
A discussion of the resistance of the lining to buckling from compressive thermal stress is given in Supplement 2 and also in Supplement 4 in the ansvers to Question III. A.6.
The coniitions assumed for buckling of Type I are conservative, and we conclude that the spacing of the stud supports is close enou6h to give e reasonable margin of safety against bucklin8 of the liner.
The detail for carrying the radial shear, namely throu6h the use of a vertical I-beam, as described in the PSAR and in more particular beginning on page 30 of Supplement 1, is in6enious and appears acceptable to us.
We recommend that careful attention to be given to the detail at the base of the I section where it is keyed into the fouLlation, to i'asure that no distress can occur in either the liner er the diagonal reinforcing bars throu6h any rotation that might occur at this point under earthquake loadirgs or other types of accident loadings.
It is noted in answer to Question III.A.9 of Supplement 1 that the i
diagonal reinforcing vin be carried over the top of the cylindrical shen and
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form a more or less completely tied unit through the containment structure with i
tie-down into and through the foundation as described in answer to Question It is further noted that the splices for the AS1M A-432 bars, which III.A.10.
comprise the diagonal reinforcing in the side valls and carry the lateral shears i
and vertical loadings in the containment structitre, vin be spliced by the
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9 Cadweld process and that less than 1 percent of the splices vill be inaccesci'cle for Cadveld splice units, and will therefore require velding. The proposed approach is acceptable to us.
The design of the intake structure located at sea level is described in detail in the PSAR sad the various supplements. Ihis will be designed as a Class I structure, with due regard for expected tsunami vater heights. Although it appears that some protection has been provided against the possibility of rock masses from the cliff falling onto, or into, the pump house, we recommend that consideration be given to impairment of the controls or the pumping system through any possible rock falls or slides.
Craues The containment crane is listed on page 2-27 (revised 7-31-67) of the PSAR as a Class I structure. We call attention to the design of the cranes to insure that these cranes cannot be displaced from the rails during the design or rr.aximum carthquake, or otherwise to have damage result from the movement of items supported by them which could cause impairment of the containment or the ability for safe shutdown.
Penetrations A discussion of the design of the containment penetrations is given in answer to question III.A.2 of Supplement 1.
It is noted there that for the large penetrations the diagonal rebars vill be velded directly to a heavy structural steel ring through use of Cadweld sleeves. This approach appears satisfactory to us.
The applicant further notes in the same section that the stress concen-i trstion in the vicinity of the opening vill be considered in the analysis. Although this approach may well be satisfactory, we believe that the penetration design should take account of any secondary effects arising from local bending, the:vl effects, and so on, to insure that the penetration-door.etail behaves
e caG.accor11y, and u. *dly that there is no distress in the conte.incent strceture in the transition zone from the penetration into the remainder of the shell structure.
Partial proof of the inte6rity of the penetration vill bc
- rovided by the measurement pro 6 ram to be made concurrently with the proof testin6 of the containment vessel. We reco
- mnend that penetration deformation calculations be made prior to the proof testing to provide demonstrated evidence that the design doec indeed meet the criteria set forth for both the large F
t.nd stall penetrations.
Piping, Valves, and Reactor _ Internals The design of the piping is described in Section 2 of the PSAR, and in further detail in Supplements 1, 2, 4 and 5 On page 1-22 of the PSAR a statement is made that all pipire vill be designed to withstand any seistic didturbance predictable for the site. On pa6e 2-30 of the PSAR it is indicated that there are re6 ons of local bendin6 vhere the stresses vill be equivalent i
to 120 percent of the yield stress based on elastic analysis for the no-loss-of function criteria. Further elaboration on the piping design is given in answer to Question II.F and Appendix A of Supplement 1, and a6ain in answer to Question II.G of Supplement 2,Section II of Supplement 4, and in answer to Questions 10 through 13 of Supplement 5 The discussion presented in Supplements 1, 2, 4 Ecd 5 indicates that the earthquake loadin6s vill be combined directly vith the other applicable loadings. For the most severe loading l
condition (involving the maximum earthquake pins normal ud pipe rupture loads) f ort.1 discussions with the AEC staff have indicated that the limit curves as S ven in WCAP 5890-1 have teen reviced such that the strain limits at temperature f
i vill consider limited strain hardenin6 no more than 20% of the strain at the maximum s*.ress of the stress-strain curve in simple tension.
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The design criteria and design approach as described above are acceptable to us.
The isolation valve design is discussed in several places but perticularly in answer to Question II. A.14 of Supplement 1.
The approach outlined there is acceptable to us.
The desi6n of the reactor internals has been reviewed in some detail with the applicant. The internals are to be designed to withstand the combined maximum carthquake spectrum concurrent with blev down in such a manner that moderate yielding would not impair the capability of safe shutdown.
On the basic of our discussion with the applicant, and the material presented in Supplement 5, the desi6n criteria and design approach proposed for the internals are neceptable to us.
CONCLUSIONS In line with the design goal of providin6 serviceable structures and components with a reserve in strength and ductility, and on the basis of the information presented, we believe the design criteria outlined for the containment and other Class I components including the reactor internals, pipin6, vessels, and supporto can provide an adequate margin of safety for
&l. 9h hw[t seismic resistance.
REFERENCES 1.
"Preliminary Safety Analysis Report, Volumes 1 and 2," Nuclear Plant, Liablo Canyon Site, Pacific Gas and Electric Company,1967 "Preliminnry Safety Analysis Report, Supplements 1, 2, 3, 4, 5, and 6,"
2.
Ibclear Plant, Diablo Canyon Site, Pacific Gas and Electric Company,1967 3
"Report on the Ecismicity of the Diablo Canyon Gite," U. S. Coast and Geodetic Survey, Rockvil.le, Maryland, September 21, 1967