ML20151G118

FOIA Request for Documents Re ACRS Subcommittee Meetings on 750218-19 Re Plant

ML20151G118
Person / Time
Site:	Diablo Canyon
Issue date:	02/22/1988
From:	Stewart M PACIFIC GAS & ELECTRIC CO.
To:	NRC
References
FOIA-88-138 NUDOCS 8804190231
Download: ML20151G118 (2)

Text

4 PACIFIC GAS AND E LE C T RIC C O M PAN Y ll# 3 --*-

7 7 BE At.E ST RE E T

• S AN FRANCISCO, C AUFORNI A 94106 . (415) 781-4M 1 e TWX 910 372 6587 February 22, 1988 EREEDOM 0F INFORMATIOli

' ACT REQUEST Director, Office of Administration

."gorys-ISP U.S. Nuclear Regulatory Commission Washington, D.C. 20555 (C'( h"f" Re: Freedom of Information Act Reauest Pursuant to the Freedom of Information Act (5 USC 552 et seq.) and implementing regulation 10 CFR 9 subpart A, we request that you furnish the documents identified in the attached FOIA request.

In accordance with the provisions of 10 CFR 9.14, we are prepared this request.

to pay fees necessarily incurred in responding to If you should have any questions regarding the request, please contact the undersigned at telephone number (415) 768-4917. Your prompt attention to this request will be greatly appreciated.

Very truly yours, A. L.

f l a u d' Mary Eliza Stewart MES: mat l Enclosure l l

8804190231 880211 PDR FOIA STEWART 88-1)$ PDR

FOIA REQUEST NRC

1. Items 2 and 3 on p. 11 of the March 18, 1975 NRC summary of the ACRS Subcommitte, Meeting held on February 18-19, 1975 on Diablo Canyon (see Attachment 1 to this FOIA) list ACRS subcommittee questions that were to be answered by the NRC staff.

2. Attachment 2 to this FOIA request is entitled "Enclosure 1" and includes some informal notes on the status of responses to these and other ACRS subcommittee questions (see Items 10, 11 and 12).

3. Please provide:

, (a) any documents that provide the response to the l

l ACRS subcommittee questions described in Item 1 above; and l

(b) any documents that provide the responses to the questions stated in Items 10, 11 and 12 of Attachment 2 to this FOIA request.

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APPLICNTT: PACIFIC CAS AND E!ICIRIC COMPANY (PGSE)

• DIABLO CANYON NUCLEAR PCfdER STATION, UlTITS 14 2

- FACILIW:

SUMMARY

OF ACES SUEC0tt1ITIII MEEFDG HELD ON EEBRUA?318-19,197 An ACRS Subcomittee Meeting reganiing the Diablo Canyon Nuclear 18-19, 1975. Power Station ws held in San Luis Obispo, California on Februarf A ccc.plete The agenda for the meeting is attached as TE. iosum No.1.

list of attendees is given in Enclosure No. 2.

Introductor/ State. Tent by Acolicant The meeting oper.ed with an int:tductor/ statement by Construction the applicant which included a status report on construction and fuel load.3 and 50% comple has reached appir:<icately 901Tuel load for Unit 1 is scheduled to begin on respectively.

,' 1975, and Unit 2 in late sumer of 1976. Shiptrant of _Nel to the site for Unit 1 is scheduled to begin in June of 1975.

Outstanding Items in Safety Review l

'Ihe staff then sumarized the status of the outstanding iters in the' 1 Diablo Canyon safety review.

in Section 22 of Supplement No.1 to the Diablo Canyon SER; this l

' Supplerent was issued on Januar/ 31, 1975. A"ong the noit intorta .9 of these items are our evaluation cf the earthquake potential' of the Hosgri Tault, effects of tsunamis caused by near-shore generators, 'Ihe seismic qualification of electrical equirrnent, ECCS and where infomation from the applicant as outstanding and when IV. solution of each item was likely.

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MAR. I 81975 Sandra A. Silver

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a Ant of San Luis Obispo County and an intervenor i j

proceedings. t Ms. Silver comrrented on several issues involved  !

i .e location of the plant in San Luis Obispo Dr.0hent County.me Di  !

/ ndicated that her ccarents muld be passed on to the Full ACRS CorrJ.t; ,

Geolcev and Seiscoloav

'Ihis presentation consisted of four sepa. ants: ate tad:s b I

' (1)  !

Dr. Richad Jahns, principal geologist since the beginning i

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of the project, discussed the geological background and the developcent of the geolcgy report for Ae site. I the general California mgionali:stien of the site and its location inHe e.phasized geology.

I (2)  !

Mr. Douglas Hamilton, geolcgy consultant, dealt spe  !

with the offshore seismic interpretation progrars. cifically  ;

(3) j seismic data and a detemination of the postula 1 that should be considered in the design of the plant .

(4) of earthquake engineering, discussed the method development of seismic input on events into vibratory greurd notion.

Dr. Jahrs concentrated on twa areas in his presentation:

(1) a brief on the pmblem of potential surface faulting; and (2) mgional tectonic pertinent charactaristics to appraisals of the site. of Southern California that are far as artificial exposures wan corcerned was aired at a detailedne ex apprM of the sub-horizontal contact between the teve cut bedrock surface and the overlying narine terrace depsits.

can be dated, it would then be pcssible to dennnctrate that if faultsSince t were found in the bedmck, and dese faults did rot disturb the ove dated raterial, then an age cailing could be imposed on the latest e

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movement of these faults. As a result of the extensive tu nching and excavation program which was conducted, it was concluded that potential surface faulting need not be considered in the plant design. With regard to the regieral situation, Jahns emphasized that the different )

trajor faults riust be evaluated in the context of their own physical i chameteristics, continuity, segment length, etc. , and also with  ;

regard of geologicto their positions and behavior throughout different parts ti;te.

- He indicated that the San Andreas Fault was clearly the decirant feature involved, but also discussed the importance of the Sun Nacimiento fault zone. He concluded by stating that for the faults in this regioral sewing, it would seem significant in considering the respective roles and'orters of significance to consider them rest specifically in the conte >rt of the past five million years since that is basically what is involved in appraising their present and potential future activity.

Ibug Harilton began his presentation by discussing so.Te of the work that has been done in surveying the offshom geology. He indicated that them am two eierents of this surveying: (1) seismic reflection profiling; and (2) gravity survey and rapping pmgram. There have been four different surveys applicable to the regien offshore from the Diablo Canyon site:

(1)

USGS Bartlett cruise in 1972 under the dimetion of Ely Silver; (2) USGS Xele:

survey in 1973 urder the dimetion of Ibily Wagner; (3)

PGSE sponsored kerk in 1973-1974 by the fi.rm of Bolt, Beranek and Newran of Houston; (4)

- PGSE of Houston.sporsored wrk in 1974 by the firm of Aquatronics, Inc.,

i Hamilton used detailed traps and track charts to irdicate the areas of ,

j coverage by each of these surveys; he stated that the interpretation  ;

of the offshore profiling inWlved integration of data from all four of these surveys. i These data were discussed in considerable detail; '

the Ahmion also Fault. He described the Hosgriincluded a detailed interpretation of the Hesgri Tault as centinuing as either one or a group of two or three breaks, and traced the fault from near Point Sal northward to the vicinity of Cape San Martin where the bmaks die out. The plant site is about two and a half miles to the inner braaks of the Hosgri Fault at its nearest point of approach. Ha:rilton e

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-4 then turned his attention to the compilation of the gravity survey data.

'Ihe rap gave gravity anorraly values for the offshore area ranging from Point Conception up the coastline to a point around Cape San Partin.

He emphasized the importance of this map, in that it gives definite indications of riajor structural features that have been trapped independently by other rmans, e.g. , the Santa Lucia Bank and Hosgri Faults. Familton concluded his discussion by surrrrarizing the major features of the area, including the large offshore Santa Maria Baain, the lesser er folded basins, including San Luis Obispo syncline, the Pisco syncline, the area of the Santa Maria Valley and the onshore Santa Maria Basin which lies generally south of the Santa Paria Val:ey dowri to where the trarsverse ranges come up south of Lompoc.

n.3 structural disturbance of these includes ver/ large faults which ave ver/ prerounced gnavity expression. These in:lude the Santa Lucia Bark and San Simeon Faults, the Faults of Rinconada and the Sur ?!acimiento system, and to the south, the faults of the transverse ranges system including the Santa Ynaz and a system of faults which

• Fas o specific narre that branches off from the Santa Ynez and then heads up toward Point Sal. Lesser faults are .lso shown in this gravity expression, including the Hosgri Fault which does have local gravity expression, but clearly not expression which is comparable either to the Santa Lucia Bark or San Sireon Faults and to other l

faults trapped onshore which include the Edra, the Pistro, and related l faults in the ground east of the San Luis Fange area.

i l Several questions were asked regarding Hamilton's presentation. Dr.

j Page asked whether there was fim evidence that the Hosgri and San Sireon Faults are not cornected? Hamilton discussed the data in l the region of the proposed corr.ection; he felt that the evidence is gcod that they are not all or.e continuous system, although he l

, qualified the staterent by saying that both faults have to be considered l part of the system of faults on the eastern bourdar/ of the Santa i Paria T>asin. Dr. Trifuruc asked what Ha.ailton's speculatiers would l be regarding the geraral serse of notion, the amplitude of notion, I and the effects of these motions on the major faults that were discussed? Hamilton responded in light of the Hosgri Fault, and indicated that the Hosgri might be cocsidered capable of a few feet of revement, although he did rot specify whether that troverent would be vertical or lateral.

Dr. Stepp of the NRC staff then cert:mnted on the inferrration presented.

He indicated that the staff had reviewed the raterial presented, and that additioral inforTration on the subject had been requested from the applicant. 'Ihis request included questions on the relationship P'C000314c.

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of the Hosgri and San Sireen Faults, a core detailed docu nntation  !

of the stnictum1 relationship of these faults in their assumed l

area of approach, and a discussion of the stnictural relationship of the Hosgri Fault to the transverse ranges faults. The stuff l j

also asked for a discussion of the nugnitude of earthqtukes that i one might expect on faults within the San Andreas Fault System that have different onders of structural significance. Finally, additioral doctrentation was requested regarding the location of the 1927 .

earthquake that occurred off Point Conception. Stepp irdicated that l the staff hoped to complete its review of this caterial in May of j this year. F. McKeown of USGS ccr. curred with the staff's co=cnts, 1 and er:phasized that the relationship of the southern erri of the Hosgri Fault to the transverse ranges could be extm.~ely im;ct taat in locating the 1927 event. ,

t Dr. Okrent then asked hcu much of the offshore infonation that is reported now was available in sufficient scope in 1967 to prompt screene to lcok for the structures ros being reported and discusse.d?

Dr. Jahns irdicated that the potential existence of tne Hosgri Fault was suspected in 1967, but that no detailed offshore sub-bottom data were available. The applicant emphasized that the geological studies perferred prior to the constniction permit review were quite extensive, and that them was no question in their mind tFat a ver/

co:plete state of the art investigation of the site had been perforred.

I Dr. Smith began his presentation by discussing the earthquakes which had been ;cstulated as design basis events for the plant; he emphasized the levels of conservatism that had been employed at the constructicn ,

l perrit stage, e.g. , the assu~ption of an earthquake unassociated with a fault occurring di.rectly beneath the plant. Smith indicated that the discover surprise, an/ of offshore faults in recent years was not really a d that events subsequent to the initial analysis at the CP stage have torne out the wisdem of the very conservative approach that was taken in considering that earthqenkes of the size postulated could occur as close to the plant site as was assured. He further ,

l stated that, based on Hamilton's interpretation of possible notion l on the Hoegri Fault, the ground cotion produced by an event of this size, at a distance of three to five miles at closest approach would certainly fall within the envelope of the kinds of grourd notion that have been proposed for the site. With regard to earthquakes on the offshore faults that have been analyzed, Srith indicated tFat these events have contained a large com onent of vertical slip. He then discussed specifically the 1927 eat thquake that was cente.md PC0003147)

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off Point Conception; analysis of the data indicates that the aftershock region had to be substantially closer to the shom than the main shock location given by Byerly in 1930. However, Smith stated that he cannot clearly associate this event with one of the presently trapped faults, although it is his opinion that the nest likely association is with the transverse runge structures.

. After several questions frem the ACRS consultants regarding location and depth of the 1927 event, ard postulated earthquakes on the Hosgri Fault, Dr. Blume began his presentation by reviewin6 the four specific fault-ead. quake situations which were postulated for the design of i the plant. He emphasized that, at the CP stage, very few methods '

were available for converting magnittde and distance into site acceleration, and that sire or peak acceleration was only one consideration that was 4 used in the design. Other equally in;crtant considerations were the damping factors assurred for various structures and systers, the duration of the shaking, the pmbability of peak acceleration, given a certain

- earthquake, and the probability of the spectral response diagram, given that peak acceleration. Blu e discussed in detail the nethods trat ,

were used for estirating site acceleration; he indicated that the principal one employed was the Site Acceleration Magnitude (SMD or Blu e Method. I After a detailed discussion of the SAM method as applied '

i to the four earthquake situations centioned above, Blu:re stated that i

he is pleased with the fact that the nethods used nearly 8-10 years

, ago at the CP stage compare e:ctremely well with those in use tcday, e.g. , those proposed by Srauble & Seed, Cloud & Coress, ard Donovan.

' Blu e then discussed the recent analysis that was perforred based on components of the Parkfield-5,1966 and Castaic,1971 carthquakes, each rcrrralized to a peak ground acceleration of 0.5g, rather than the 0.4g that was used in the origital design. He also centioned the Koyna transverse earthquake in India as being close to the situation thisthe dt Diablo Canyon site; an acceleration of 0.49g was observed fmm event.

4 Dr. Trifunac asked a quest.on regarding the SMi nethod as described in l Dr. Blume's paper in the 1965 World Conference Proceedings. Triturac indicated that the use of this cethod by Bltrre appears to result in accelerations which underesticate all present available data by a factor of 0.5 to 0.8 on the logarithmic scale. After a lengthy discussion, i' Blure agreed to get together with Trifurac in an attempt to resolve this apparent discrepancy.

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, Dr. Kapur of the NFC staff emphasized the part played by damping values in the detemiration of response spectra. He indicated that the damping values used by the applicant were very conservative, and that the staff considers the msponse spectra calculated by the applicant to be quite conservative.

Dr. Okant then asked the USGS to elaborate on their statement that a design acceleration value of 0.5g is not adequate? James Devine of '

USGS indicated that this staterent was meant to leave the issue open because he'did not feel that all questions had been answered at this

• point. Devine stated that r : cent work by Dr. Smith concerning the location of the 1927 event. along with some unpublished work by the USGS, irdicate that thert is still profitable infomation available concerning that earthquake which could alter the obligaticn to put it on the Hosgri. He also emphasized the incertance of the ranking of faults with regard to the resolution of this question. Okrent then asked what approach the USGS would take regarding the natum of the Hosgri strwture if the 1927 event had never occurmd? Frank McKecwn of USGS responded that there is no definitive evidence to tie the Hosgri and San Sineon Faults together, but that the possibility cannot be ruled out entirely. He indicated that it is very difficult to assign a given sina earthquake to the fault because you are not

dealing with a single continuous break; it consists of many, many breaks. Dr. Trifurac asked whether the applicant's four proposed j design basis earthquakes could be considered masonable if the 1927

) event were elimirated? Devine replied that he felt that all four were masorable at the tire of the CP, and that he still feels that they am reasonable with a proviso on earthquake D (the event unasscciated l

with a fault), that being that the Hosgri be examined nore carefully after the applicant msponds to the staff's recent request for additieral infomation. He irdicated that this infomation will help to better esticate the raxinum carthquake that eculd occur on the Hosgri Fault which in effect r.cw controls the undesigrated earthquake D.

Dr. Okmnt asked the staff whether the acceptable seismic design criteria for Diablo Canyon 1 and 2 would be the sare for additioral u tits, if such wem pmposed? Dr. Stepp irdicated that the staff's ,

seismic design criteria have corstantly been upgraded as our under-  !

standing of the pmblens of earthquakes ard earthquake spectra properties change. He stated that we would always consider the pmbable raxm:m earthquake for the site in our evaluation, regardless of whether the plant was partially built or not. Dr. Shao emphasized that the l

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MAR.1 319M staff will consider all steps in going from the g value to response spectra and dar: ping values, including the methods used, and then a decision would be made regarding the adequacy of the seismic design.

After more discussion, Shao indicated that if the g value holds at 0.5, and the applicant has employed the criteria and methods which have been stated, then 2e plant is probably adequately designed for seismic loads. Dr. Okrent then asked what probability per year of safely shutting down the reactor in the event of an e.arthquake, that the staff is seeking for Diablo Canyon? Dr. Denten replied that the staff does not use a probability approach in selecting safe shutdown earthquakes ' (SSE) . He stated that the Comission's criteria, as set forth in Apperdix A to Part 100, provide a fram.ork to work in to arrive at an SSE; we then have to couple that with the design approach and the design of structures and components in order to arrive at an evaluation of adequacy of the seismic design.

Dr. 'Ihompson pointed out that, after all the discussion that had transpired, the question of whether the Hosgri Fault would be expected to exhibit predominant strike or dip slip had not really been answered. Holly Wagner of USGS cc: rented in detail on the findings of his survey, but did not reach any finn conclusions reganii.:q the preference for strike or dip slip.

Seismic Desien i

i Mr. Wollak of PGSE began the session on seicenic design with a presentatica on the design criteria for the major cceponents, and hcw Dr. Blure's criteria have been implemented. Wollak stated that the seismic analysis of Seismic Category I stm etures, systems, and components is based on the input frae field grturd notions ard the resulting response spectra for the operating basis and safe shutdcwn eatt. quakes. Four dymmic retheds of seismic amlysis wem uscd:

(1) Time history nedal superposition; (2) Response spectrum rodal superposition; (3) Response spectzm single degree of freedom; and (4) Method for rigid equipment and piping.

After discussing design procedures in detail, Wollak cormented on some recent work which was done to compare the safe shutdown earthquake response of t/pical Category I'struct.:res, systers, and corgonents to that which would be induced using ::rdified input asponse spectra and PC000314Gr

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i the damping values given in Regulatory Guide 1.61. These modified input response spectra were derived fmm acceleration time histories fer components of the Parkfield-5,1966 and Castaic,1971 earthquakes, each normlized to 0.5g. The spectral content of these records is considered mpresentative of the vibratory ground motion expected at i a site with foundation material similar to Diablo Canyon, and generated frcm a nearby source. A ccmparison of these modified spectra with the spectra and damping used in the SSE design confims the seismic '

design adequacy of typical Category I structures, systems, and components, i Wollak concluded his presentation by stating that the seismic design '

.' tesis for major plant structures and ecmponents includes significant i conservatism in the fonn of design spectra (unusually rich in high I fmquencies), ver/1cw assumed damping values, and an acceptance i criteria based on overall elastic behavior under seismic loadings.  !

1 Dr. Okmnt asked whether a calculation had been done using 0.5g peak acceleration and the respense spectra and damping values of Regulatory 1 Guide 1.60? Wollak replied that they had not done this. The staff then cor:mented on the applicability of the response spectra in 1.60, and also on the reasoning behind the selection of the Parkfield and Castaic earthquakes as ccmparisons for the Diablo Canyon site. )

Dr. Okmnt emphasized the i:nportance of knowing, with scme degree of assurance, that all safety related structures, systems, and w.wnents will be able to survive an earthquake of given acceleration, e.g. ,

0.5g. Mr. Lindblad stated that once seismic design :riteria were chosen fer the plant, all structures, systems and ccmponents were designed to meet these criteria. He indicated that he feels that i there is conse.:vatism in the overall design.

I After additional discussion en loading factors and the different seis,aic design situations where the OBE and SSE centrol the design, Dr. T. C. Esselmn of Westinghouse presented the seismic design criteria that wem used for the primary loop components and piping.

He reviewed the methods used for each ccmponent and for piping, and irdicated the margins that resulted fmm the analysis. Dr. l Okmnt asked whether the staff reviewed the seismic rrodeling of l various cceponents in the prirary Icep. Dr. Kaour replied that l

Westinghouse has documented many codes involving this rredeling, l and that the staff has reviewed these codes in scoe detail. The possibility of failure of the turbine building (a non-seismic ,

Category I structure), and the effect of such a failure on Category PC000314R men e,mean e ese e me

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i I systers was discussed. The sta.ff stated that all such systems in the turbine buildirg had been adequately pmtected against such a failure.

With regard to this item, Dt. Bush asked alcut the supports on the valves, that in the event of loss of pcwer during an earthquake, what is the i reliability regarding closure of the valves? Westinghouse agreed to '

pmvide infomation in response to this question at some later date.

ACRS Questions Regarding Geolor/-Seisrology and Seismic Desien .

Following.a short executive session, the meeting reconvened, and the l follcwing questions were raised by several of the ACRS members and ,

l consultants:

Dr. Trifunac (1) In light of previous discussions with John Blume, justify the  !

apparent discrepancies in the relationships used.  ;

.(2) Referencing question 1, wMt would be the calculated peak acceleration using other currently available methods?

(3) What would be the effect on the response of the plant of a small ragnitude earthquake which pmduces very high peak accelerations?

(4) When this peak acceleration has been derived, would it be possible to calculate confidence levels on this value?

(5) What is the maxirm historic, as well as predicted, nodified i

Mercali intensity at the site due to any earthquake any place, and l

what would be the peak acceleration resulting frcm it?

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Dr. Thecosen^

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1 (1) He inquired alcut copies of USGS Open File Report 74-272. Mr. I Devine of USGS agreed to provide several copies of this report. l Dr. White (1) Provide additional evidence to de.monstrate that the Castaic and Parkfield earthquakes (ncn alized to 0.Sg) really have lesser effectr. en the Diablo Canyon stmetures than the original design earthquake.

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, Dr. Okmnt (1) What kind of errorr ,.:an arise in the seismic design analysis?

(2) What are the sounes of error in going fr m the earthquake itself via a one dirensional seismic model to the finite element rrodel?

(3) Assuming that scce peak g value is adopted by the staff as adequate, justify that the calculations based on the Castaic and Parkfield  :

spectra pmvide the necessary assurance. l

. (4 ) How do's e the staff decide what constitutes an adequate audit of the seismic design analysis? (Reference the Appendix to Draft WASH-1400 which includes a partial design check).

Dr. Okrent asked the applicant and staff to be prepared to discuss these questions at the next Diablo Canyon Subcorrmittee Meeting. (The last question is for the staff only). i Seismic Desizn (continued)

Mr. Dorrfcott of Westinghouse then pmsented the design criteria and qualification requiments for safety related instramentation. He listed the instnrent control electrical equip ent that had been qualified in testirg pmgrars; this equipcent was tested in full-scale testing pmgrams and qualified to design acceleration levels. Dr. Okrent asked

, if an carthquake with a larger higher frequancy ccc;cnent than the ene analyzed would appreciably affect the perforrance of the instnrr.entation? l After seca discussion regarding the effects of damping, etc. , Okrent i asked the applicant and Westinghouse to lcok into this matter. Dr. Kapur '

ccarented that equipnent at higher elevations in the plant does not experience the verf high frequency eccpenent, and so the problem is not i so sevem. Mr. Ebersole pursued the discussion with regard to possible i contact charter in switches, etc. Dorrycott responded that Westinghouse is pursuing a failun moda and effects analysis with regard to the  ;

resolution of this pmblem. The staff indicated that they hoped to have I tha issue of seismic qualification resolved prior to ocmpletien of the Diablo Canyon review by ACRS. With regard to qualification, Dr. Bush bmught up 2e possible interactive effects of saismic anc envim: rental qualification; he asked if any work had been done in this area? After scme discussion, it was agreed that this problem had not really been addressed.

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wa. i e 192s Dr. Bush then bmught up the subject of experimental confinration of vibration characteristics of rajor reactor components, and the respnse of safety instn: mentation to seismic loadings. Uds was an agenda item for this meeting as well as having been cited in the ACRS CP letters for both Units 1 and 2. Mr. Lindblad indicated that a number of programs have been instituted in response to this concern:

(1) Equipment qualification dynamic tests, as discussed by Mr.

Dorrycott.

(2) Dynamic tests of expansion anchors (tests sponsored by PGSE at the University of California).

(3) Cceponent tests conducted at Indian Point 2 and San Crofre on components similar to those which will be used at Diablo Canycn.

i With regard to item 3, Dr. Lin of Westirghouse discussed the applicability of these cur.ponent tests to Diablo Canycn. He

, firr.t discussed in detail the seismic qualificatien of instrurentation, in response to earlier questions. He then indicated that vibration testing of the reactor ecolant loop and steam generator bad been perfomed at Indian Point 2. He indicated that data were available fIun San Onofm, both fran shake tests and frun effects of the San Pemando earthquake. Lin also discussed some full-scale testirg on a Westinghouse reactor in Japan.

C4) Testing of rodels of pipe and pmssure vessels for seismic damping i characteristics (tests sponsored by PGSE at UCLA).

(5) Installation of plant seismic instrutantation to recond the

small earthquakes that may occur during the coming years of l operation.

1 Dr. Okrent asked whether PGSE had any plans for full-scale shaking of the Diablo Canyon Plant? Mr. Lindblad replied that they did not, and that they felt that the conservative damping assumed in the design pmvided sufficient margin such that full-scale shaking to mproduce the ratural period of vibration was not mally necessarf. The staff added that unless one could simulate accelerations close to the SSE, e.g. , 0.4 to 0.5g, the benefits of such testing would be srall. The point was also rad.e that artificial testing to such lag,e accelerations would be extremely difficult.

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? MAR.I e 1375 Seismic Scram The last agenda item of the day involved a discussion of seismic scram.

Mr. Lindblad indicated that PGSE had reviewed the recent LiverTrcre report on this subject; he stated that the report leaves many questions open, and that at the present time, PGSE believes that an autccatic trip of the macter at the onset of an earthquake does not necessarily improve

, the safety situation. Dr. Okrent asked whether the applicant had prepared some kind of list detailing the gcod and bad features of a seismic scram?

Mr. Lindblad stated that they had done this at various times, and that  ;

on the bad . side, such a scram introduces a non-standard condition for the 1 reactor, a transient involved in shutdewn, loss of one of t te sources of power, and an additional need to conitor a changing ope:atien in the plant on top of the stress of the earthquake itself. Dr. Okrent then I asked whether PGSE had evaluated the plant to see what level earthquake l would lead to trip, whether you wanted it or not? Lindblad said they had not, but that he would esticate something of the order of a 0.lg

. acceleration value. Utis could be a reacter trip, turbine trip, or perhaps some other com4cnent, and would not necessarily initiate an autonutic reacter shutdown. He added that he did not feel that it was  :

gcod practice to shut the plant down for any earthquake, only for tMse I uttich are potentially da raging to the plant; he did not think that PG6E

. should tolerate spurious trips of the reactor for srall earthquakes.

Okrent asked atcut the possible merits of an early scram for an earthquake 1 which is going to cause a loss of coolant accident (LOCA). Dr. Kapur  :

l stated that the nest important reason for having a seismic scram is that '

3 i if the earthquake is accccpanied by a LDCA, the peak clad temperature I could be significantly reduced. He then censidered various postulated i earthquakes. For earthquakes of the ordar of the OBE, e.g. , slightly I gmater than or equal to the OBE, the operater is required to shut dcun  !

, the plant. For earthquakes nuch gmater thin the OBE, scrre dange will be incurred, but within the SSE, the plant is still designed to be safely shut down. For earthquakes in this range, there are other nonitoring systems which will trip the plant. Kapur also cited the problems of spurious sigr.als and unwanted transients in concluding that he did not feel that a seismic scram was desirable at this time.

Mr. Ebemole raised the question of d-c power supplies with regard to bmaker closure or trip in the event of an eartrquake where one bas generator trip. 'Ihen, what are the seismic qualificatiens of the switchgear and power supplies? Mr. Herrera of PGSE indicated that the batteries for the switchyards hsve earthqua'<e bracing and are designed to withstand accelerations of at least 0.2g.

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Dr. Okrent asked whether one can engineer a seinic scram system with I a high degme of reliability, e.g. , a reliability such that one has a pmbability of spurious scram no larger than one in a 100 or one in a 1000 per year? Considerable discussion ensued on this item, with the i general conclusion being reached that such reliability could probably ,

be achieved if the thmshold level were set far enough above the I acceleration for the OBE.

After additieral discussion of this item, the meeting adjourned for the day.

. ' . Systers Interactiers l he meeting for the second day began with the subject of systees inter-actions. The reference fer this discussion was an ACRS letter from Dr.

Stratton to Mr. Munt:ing (dated Nove nber 8,1974) titled, "Systems Aralysis of Engineered Safety Systems". In this letter, the Committee

, indicated that attentien to the evaluation of safety systers and associated I equipment from a multi-disciplinary point of view .: identify potentially l undesirable interactions between systers is becoming inemasingly '

desirable and important. The letter then contains several examples to I illustrate this there.

After soce general eccments by Mr. Lindblad reganiing the natum of the

, letter and its applicability to Diablo Canyon, Mr. Ebemole posed a

! series of questions and situations regarxding the applicability of this

letter to the Diablo Canyon Plant. Ebersole had visited the plant the pmvious day, hese questions and situations are su marized below:

, (1) In the event of fire in the turbine building, it appears that there I

could be ventilation problems in the 4 kV vital switchgear reces and also in the diesel generator compart:ments. For the switchgear Imms, them is ccrmen atmospheric coupling between these roces, and it appears then that there would be conmunication between trase rocas in the event of a fire in one of them. In the case of tre diesel generator compartments, if the generater end of the diesel is isolated, i.e. , the mil-down dccrs are cl: sed, one would have a situation when the generater could recieve very little cooling, causing a temperature rise in that part of the room and a possible overload condition and resultant a-c power outage.

(2) The plant bas many pain of rotating shafts of various sorts serving different functions. Rese am typical redundant configurations of services which are on line at all times (not engineering safety feature designs). !bw, "suppose one postulates the failure of one PC000314N\

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MAR. I 81975 of a pair (say train A) which serves seme specific function. Has the applicant examined the concequences if the altemate service, say train B, does not respond pIrperly as a function of time?

Examples might be service functions which control ventilating syste s, water supplies, etc. In other words, the interest here is the thesis of non-msponse of backup trains of active services, and a consideration of the time delay involved that might be an abnomal delay rather than nomal. An extension of this might be, if the .

backup service does not respond, what time is available to repair the service or else pursue an altemate course ef action?

(3) The Pasmussen Reprt discussed the total loss of all a-c power, and included s ce probabilities en the length of tifra before power might be restorec. With regard to this situation, has the applicant considered this loss of power in light of the stoppage of rotatirg shafts and a possible te.perature excursion in the containment to values of the order of 400-500 F? Mr. Lindblau indicated that they had reviewed tnis general type of situation, and that the contairrnent would not exceed its design te:nperature. He further added that with loss of a-c power, the containment heat input is reduced by about 85% because of the less of the rcrmal heat loads fmm the reactor and the reactor coolant pumps.

(4 ) In the case of small IDCA conditions (lag,er than the chargirg i pump capacity), one has depressurization of the prira:y system.

For this situation, can the applicant describe the heat transport paths to the ulti. Tate heat sink? Possible paths are the residual heat reroval system (but there is probably not sufficient flow

here), the ccrnponent cooling water system (which passes thmugh the containment fan ecclers) coupled with the auxiliary saltater system, or natural convection in the steam generators. As a function of break size, what fractions of the heat are carried along these various transport paths to the ultimate heat sink? .

An additional question raised was, what will be the ambient temperature surzeunding the auxiliary feedwater punps, as a function of time, in the absence of ecolirg and ventilation in these pump Imms?

l (5) For the auxiliary saltwater system, one of the auxiliaries is a ccrmon pair of sump pumps in the intake stIveture to pump out leakage, if necessary. These pumps muld be subtrerged under a high wave condition. hhat are the criteria for the design of these sump pumps? In addition, the piping for the saltwater pumps is supported by connection to a non-seistric structure, PC000314W

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namely the condenser dischary,e conduits. 'Ihe idea of a seismic piping system anchored to a non-seismic structure appears to deserve some clarification. The coupling of the auxiliary saltwater piping to the earthen fill and the building foundatien was also discussed.

(6) Again with respect to the sump pmps for the auxiliarf saltwater system, it was mentioned that these pumps would be flocded under verf high waves. Under this condition, m uld the integrated intake' of water into the louvres be such that the sump pin:ps would not te required in the sMrt-tem following this flooding?

(7) The cable link that supplies power to these sump pumps is an example of cabling which is intemittently subjected to fresh-and salt-water flooding, khat qualification of this cable has been perferred to ensure its function under the conditions of altemate drying and submergence in either fresh-or salt-water?

l (8) With regaM to the hot shutdown panel, is them a possibility that in providing this auxiliary function, you really have not recreated i a new scene for cor=cn vulnerability of damage? In other woMs, is there really independence frczn the control Ix:o1 with regard to g this panel being a center of active functions?

i Each of the ite s raised by !t. Ebersole was discussed in considerable

. detail. Dr. Okrent asked both the applicant and staff to be prepared to i

discuss and resolve any outstanding questions on these items at the next Subeccmittee Meeting, i

, Dr. Bush then raised the following two questions: I t

(1) Has the applicant considered the problem of pMsphate build-up with regaM to closum of valves on the turbines? This question is nelated to the response of non-seismic valves under severe seismic shaking. Are there any reliability statistics regaMing closua of such valves under seismic loadings (when generator load has been dropped)? Mr. Lindblad indicated that the Earthquake Engineering Research Institute does collect infont.ation of this scrt. With regard to contactirp; the aleve-mentioned Earthquake Institute, Bush suggested thcc data from Alaska also be obtained, e.g. , data frun the 19% Alaskan earthquake.

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(2) If you assume a failure of orn of the inlet lines .to the steam '

generator so that you Mve the' full impact of the jet forces, as well as the jet forces fw m the exhauat frem the steam generator, and then impose a seismic loading as well, does this' situation fall within the desig;n envelope? ' '

/

(3) Dr. Okmnt asked that the staff reexamine in detail the tredeling of the primary ecolant pump under a seismic loading, to be ,

assured that this modeling has been done properly. . ) '

(4) Mr. Koffman asked what accelerations might be experienced >in

. the control room for the design SSE acceleration of 0.4g?

Mr. Lindblad estimated between 1.6 and 2.0g, but indicated j tMt they Sculd look further into this item. KoffTran stated 1 j -

that this could be an additional argurnent for having a seume 1 scram. l

, As a concluding re ark to the generi subject of Systems Interactions, , 1 T. Hirens indicated that the staff Es' had some prelimirary discussions with ACRS as to h:w seme of these situations sh:uld be handled. It ic' planned that trany of them can te incorporated into various sections I of the Standard Review Plan. A special ACRS Subcor:mittee, with Dr. '

, Bush as chairran, has been set up to begin reviewing some of these items with the staff.

t

! Electric Power Systems l

l i Mr. Herrera of PGSE opened this subject with a presentation on the

offsite power system for Diablo Canycn. He stated that the inter-connected PGSE 230 and 500 kV electric transmission systers will

serve as a two-system source of offsite power for the Diablo Canyon Units. The twa generating units will be connected to the transmission system by means of two 230 kV and three 500 kV lines em'uting frem 1 their respective switchyards. These yards are physically separated and independent of each other. Each of the 230 and 500 kV lines supplying the Diablo Canyon switchyards have primary and backup protective ry_ laying systems and autemtic closing features. This will ensure fast and proper clearing of all electrical faults, and will permit automatic restoration cf pcwcr fwm the system if all conditions are proper. Stability studies which have been conducted on the system indicate that the loss of any single generator in l the system, including that for either Diablo Canyon Unit, sinile operating at full load, will not advert.ely affect the stability of the remaindcr of the transmission grid. He concluded by stating that the design of the offsite poier system meets the intent of General Design Criteria 17 and 18, IFFJ Standard 308-1971, and Regulatory Guide 1.32.

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- l Several questions w.re raised reganding the pmsentation on offsite i

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power. Dr. Ohent asted if figures were available on system reliability '

tMt muld p. vide a basis for judging the probability per year of

' losing all offsite power to the Diablo Canyen site? Mr. Herrera indicated that specific figures were not available. Mr. Ebersole asked if PGSE ,

was taking any steps to upgrade the load rejection logic to prevent '

cascade as the nuclear units ccme on to the system? Mr. Herrera indicated that they were. Dr. Bush asked if, under a seismic loading, can you bcotstrap yourself to the turbine fTom a startup condition,- '

as contrasted to a load rejection continuing operation? Mr. Lindblad m sponded that they could, a .

Mr. Nielsen of PGSE then made a presentation on the onsite power system for Diablo Canyon. '.his system consists of the output from the main generater and an auxiliary power system composed of 12,000, '

4160, and other 1cw voltage systems. All auxiliary system buses can '

be fed frem either the rain generating unit or from the standby-startup

' offsite source. The emergency oker system can also be supplied by the diesel genera: Ors. The engineered safety features and other emergency services are fed from three 4160 volt buses, each supplied by a diesel ,

generator as well as by the ncrmal offsite and rain unit sources. ESF loads have been gtruped to meet single failure criteria. Two diesel '

generators are sufficient to carry the emergency loads that are >

required for safe operation under norral and accident conditions. One diesel generater is comon to teth Units and is autmatically transferred to the Unit which mquires actuation of safety features. The onsite d-c power system consists of a 125 volt system. The system is divided into 3 groups, and each batte~/ has its own battery chargers and

,  : switchgear. The batteries have the capscity to supply their loads  ;

for the time duration required, even without allowance for the diesels  :

imediately relieving some of the load.

I Dr. Okrent asked what happens if, in a seismic event, both reactors indicate that there is a LOCA? Nielsen indicated that whichever Unit ,

receives its accident signal first will obtain the load frar. the swing I diesel. After additional discussion, Okrent asked if anyone has  !

i looked at the reliability uf this situation, and does one have the 3 necessary reliability? He further stated that he felt that the staff

)

4 should lock in detail at the design of everything that one needs to function in order to get onsite power (both a-c and d-c), given an carthquake large enough to have a reasonable chance of losing offsite power. Finally, Ohv_nt asked if the staff had considered the possibility l of s uential effects due to earthquakes, a.g. , offsite power going off I ar ' Nie)sen indicated, for the example cited, that once the diesels j 1

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come up to full speed (10 to 12 seconde), the offsite power source would be locked out. W. Ebersole raised some additional questions regarding the change-over frem offsite powr to the diesels, e.g. ,

valve actuation. Nielsen responded to these questions for P3SE.

Finally, Ebersole raised the concern that the day tanks for all five diesels are supplied through a tsc-tank, tw-pipe, tw-electrical pump fuel oil system, and that the state of the entire fuel oil system depends on gettirkg powr to these two sml1 pumps which '

must cycle on and off frequently. Mr. Lindblad responded that the system meets the single failure criterion, and that he feels that

, it is adequately designed to perform its intended function.

Lockout of Pcwer to Motor-Ocerated ESP Valves A letter on this subject frem Dr. Kerr of ACRS to W. Muntzing (dated January 14, 1975) had been distributed earlier in the meeting to the applicant and staff. The letter raised some questions regarding the preposed lockout of p:wer to the above-mentiened valves. T. Hirens of the staff indicated that the position stated in the Diablo Canyon Safety Evaluation Repcrt was unchanged at this time. Mr. Lindblad stated that PGSE's position is that they pmfer to traintain operability 4

of the valves frm the control rum.

Mr. Gomly of PGSE then began his presentation on this mbject. He used a piping diagram to indicate the nine valves which the staff had flagged with regard to lockout of pomr. The trost important of these are the single valves frun the refueling water storage tank to the safety injection and PER p wps. Several questions were asked during the presentation regardir,g the size of the valves, valve operators, annunciation of valve position in the control rum, etc. Germly detailed the inforration that muld be available to the operator to indicate that one of these valves was closed, and the steps that the operator could take to open them. He indicated that they bad j

mde no ccrnprehensive evaluation of the probability of spurious  ;

closure of one of these valves.

Seveml of the questions in the ACRS letter on this subject were then discussed in light of the Diablo Canyon design. These included an evaluation of the probability of a spurious signal, time interval required for reactivation of valve operator c.fter loss of power, question of whether signal lights are lost when the circuit breaker is opened, reliability of valve indicators, etc. The discussion ,

concluded with Mr. Lindblad stating that the applicant would like additional ti:ne to consider seme of the questions in the letter. 1 The staff also indicated that they would Mspond later to these {

questions. '

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6 MAR.1 G 1975 Miscellaneous Questiers (1) Mr. Ebersole cccrented that the plant contains.various hydmgen storage systers and lines throughout the plant. He brought up the general subject of hydmgen release and accumulation. Mr.

Gomly mspended that they had taken this pmblem into account in decigning the plant. With regaM to hyd:rgen evolution out

, of the batter / reces, Mr. Nielsen stated that they had studied this pmblem in detail (partly at the request of the staff), and ' '

that .the analysis showed that it kould take 28 days to accumulate

. enough hydrogen to approach the minimum explosive limit, assuming complete loss of ventilation.

(2) With regaM to inservice inspection (baseline), Dr. Bush stated that the Units apparently meet the criteria set forth in ASME Section 11-1971; in this regard, he asked how this compres with the 1974 cede? "r. Lindblad replied that the areas of non-ccepliance with Section 11 of the 1974 Code are ver/ limited in nature. This question will te discussed in greater detail at a future meeting.

(3) Dr. Okrent asked if in the routing of electrical systems, are i seismic Category I and non-seismic Category I lines ever placed in the sa .e cable tray or penetration? Mr. Nielsen replied that they are not. Okrent then asked if there are possible redes of overheating for the non-seismic lines which could lead to a loss of penetratien integrity? After scoe discussien, Okrent asked the applicant and staff to be prepared to discuss this item at the next reeting.

Emercency Plan Mr. Shiffer of PGSE discu.ssed the emergency plan for the Diablo Canyon Units. He indicated that in the development of the plan, prirarf consideration was given to the December 1970 AEC guide for the preparation of emergency plans for production and utili::ation facilities. The plan includes previsions for prirar/ and alternate energency cont:cl centers, notification of offsite state and federal agencies with responsibilities during an emergency, onsite first aid and decontamination facilities, and energency radiological ronitoring equipment. Shiffer irdicated that the plan describes a spectrum of accidents and the specific action levels to be taken for pmtective measures. In the event of an emergency, the San Luis Obispo County Sheriff's Departr.ent is ms;cnsible for coordiration of any initial pffsite protective measures which may be required.

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Dr. Okrent asked if PGSE had developed within their own procedures, the specific inferration, the instrrentation, and the evaluation of these readirgs such that the operator or scce other responsible persen could detemine the nature of the events, given scme postulated accident? In the questien he included the rarge of situations discussed in Draft WASH-1400.

Shiffer replied that their precedures did include specific  !

offsite nenitoring technigecs, and procedures for interpretation of nonitoring results, e.g. , dose conversion tables. Ccnsiderable discussio,n  !

ensued on this ite:n, with Okrent emphasizing that early waming time of accident details was an im;crtant consideration in Draft WASH-1400.

Shiffer indicated that they have icoked at high temperature radiation conitors inside centainment, and also the possi' ility of a detector outside centainTent icoking at either the extner concrete surface or at the liner at the containi.ent equipment hatch. However, he questioned the validity of the interpretation of data which might be obtained from such irstn=ents. T. Hircrs indicated that the staff is still reviewing this question, both in a generic sense and specifically, for the Diablo Canyon Units; a draft Regulatory hide on pcst-accident instrumentation is currently being form 21ated. Ok: tnt asked both the applicant and staff to te prepared to discuss this item at the next rasting.

Miscellanecus Cuestiers (continued)

(4 )

Mr. Ebersole cccmented on the setting of valves in the RF2 system, i.e. , the setting of valves to cope with the problem of pipe break with regard to the paths which the water cot.ld follow. The question i on this pertained to the fairly simple inscmetion en an FSAR drawing regarding adjustment and locking of a specific valve; Ebersole felt that perhaps this instruction should be expanded because of the nuc.ber of possible fault situations. Mr. Lindblad replied that indeed rore detailed instmetiens are available for the operators. l 1

(5) Ebersole asked atout the intemediate connen C train in the i ecmponent cooling water system. If a major leak occurs in this '

C tzwin, hcu do you prevent the operator frera siinply drying up the system by p'xnping the alternate water inventories in the A and B trains into the sea fault? Mr. Gomly discussed the nonitors which would alam such a fault, and indicated that the C header would be isolated before any substantial loss in backup water supply had occurred.

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(6) Dr. Okrent asked whether the water hamcr problems experienced at Indian Point 2 could be expected to occur at Diablo Canyon? Mr.

Lindblad indicated that both Westinghouse and PGSE are currently reviewing the installed Diablo Canycn system to see how it compares with the Indian Point situatien. Okrent further asked t/ ather Diablo Canyon vould te subject to the associated effect of contairment liner heating that accompanied the feedwater line rupture at Indian Point? Lindblad stated that he did rot think so, and that .

Diablo Canyon has a different feedvater design in that welds are recoved from the immediate area of the liner plate.

(7) Okrent postulated a LOCA situation dcunstrean of the steam generator where a bc-phase mixture coming out of the vessel might lead to dyramic forces, particularly in the steam generator. He asked whether Westinghouse had done any fu%cr examination of this question? Dr. Peacock indicated that Westinghouse had ccmpleted an analysis of the prirary to secondary system interface in the steam generator; the analysis considend the dynamic loads resulting from seismic forres, blowtL~,n, and varicus lead carbinatiens. One conclusion of the analysis was that slug flow tould not be predicted by the blowdown process. Peacock

- stated that this Scrk was docu .ented in a WCAP reocr which was suhaitted to the staff over a year ago. Okrent asked the staff to check en the review status of this report and cerrment at the next meeting.

(8) Okrent asked if the staff had reviewed the kinds of insulatien used at Diablo Canyon, and examined the potential effects of insulation in the sump in the event of a 14CA? Hirons indicated that the staff had requested and received this infomation from PGSE, and that we were still reviewing it for acceptability.

Okrent asked for additional discussion on this at the next meeting.

(9) Okrent asked if it was planned to run the Diablo Canyon containment in the purge made while the zwactor is at po sr? Lindblad replied .

i that the purge valves would nemally be closed. He further added that the purge valves have the capability cf closing durir.g a IICA.

(10) Okrent asked whether the question of unacceptable forces en the check valve seats in the secondary system had been examined?

Mr. Lindblad responded that this questien had been analyzed by their consultant (Nuclear Services Ccrporation), and that the a

valve integrity wes found to be satisfactory; he also stated that e

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the staff had reviewed the analysis and found it to be acceptable.

Mr. Ebarsole pursued the discussion with regard to one of the check valves experiencing stea . ficw reversal; he asked whether the discs will survive the tremendous impact upon closure. Mr. Allison of the staff stated that the discs would be deforr.ed but not bmken. In relation to this problem, Ebersole suggested that a pipe break in the vicinity of these valves could indeed effect the valve in the opposite line and possibly result in the blowdown of two steam generators. Lindblad stated that their analysis -

had shown that the second valve could withstand the failure of the first line. Peacock er.phasi::ed that protective functions have l

. be m incorporated in the design to assum that only one steam t eacrator blows down.

Conclusiers Another Diablo Canycn Subec=ittee Meeting will be scheduled once the evaluation of Geology and Seis. ology has been completed. The staff plans to cwplete this evaluation sortatire in M.sy of this year.

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'1homas J. Hirens "

Light Water Reactors

Project Branch 1-3 Division of Reactor Licensing

Enclosures:

1. Proposed Agenda

2. Attendance List cc w/ encl:

Mr. John C. Fbrrissey Philip A. Crane, Jr., Esq.

Andrew J. Skaff, Esq. u Mr. Frederick Eissler Ms. Elizabeth E. Apfelberg Ms. Sandru A. Silver i Mr. John Forster  !

Mr. Ia nie Valentine I Mr. William P. Corra ll Mr. W. J. Lindblad Mr. J. W. Darryectt PCr00314V .

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DJCIDSL*DI !,'O. 1 l ._

PROPOSED AGENDA DIABLO CANYON UNITS 16 2 SUBCOMMITTEE MEETING FEBRUA RY 18-19. 1975 - SAN LUIS 031SPO, CALIFORNIA 1

PRINCIPAL SPOKESMEN: W. J. Lindbled - PC6E, Projec t Managor _

Tom Hirons - Project Manager, Reg. Staff TUESDAY. FEBRUARY 18. 1975 (30 min.) I. Executive Session - CLOSED -(8:30 a.m. - 9:00 a.m.)

(5 min.) II. Introductory Statement (PC6E)

A. Bricf Description of Site Location / Layout '

B. Construction Status - Units 1 & 2 C. Fuel Load / Opera tion Schedule (15 min.) III. Project Review Su,mmary and Status Report

, (n L,$

A. Update on Sept'.. 1974 SER Unresolved /OutstandinC Items .

B. Resolution / Status, of ACRS CP Letter Items (2 hrs.) IV. Site Characteristics L_.  ; A. Geology / Seismology .

, 1. Detailed Status of DL Acview -

(DL/USGS)

2. Applicant Pecsontations (PC6E) a) Basic Geologic / Seismic Data b) Vibratory Cround Motion i

"

• c) Surface Faulting d) Of fshore Scismic Interpretation Program e) Determina tion of SSE and Seismic Design "g" Value for Si te (30 min.) B. Tsunami Analysis (Model/ Analysis / Review Status) (PG&E/DL)

(15 min.) C. Tornado Design /Critcria

1. Applicant Presentation (PG&E)

2. Conformance to Current Criteria (DL)

3. Systems for Sa fe Shutdoun k'eakly Protected (15 min.) D. (PCEE/DL)

Other Site Characteristics

1. Me,tcorology, Hydrology, Demography, etc. (PG&E)

(1 hr. ) V. Scismic Design A. (PC6E/DL)

Design critoria for Containment / Major Components B. Significant Changes in Design Since CP Stage

, C. Design Criteria / Qualification Requirencnts for Safety-Rela ted Ins tr.

D. Stress Levels at 0.4 3/0.5g/ Higher "g" values 4

1. Safety Related Systems Most Vulnerable to Scismic Events E. Possible Ef fcet o5' Non Seismic Class I System Failure on Safety .

(15 min.) VI. Experimental confirmation of Scismic Design Aspects ( l'Gr ii)

(30 min.) VII. Scismic Scenm A. Existing Designs /Availabic Methods (PG&E/DL)

D. Experience & Relia'aill.ty Consideratiotn PC000314W m, , -- --- -- -- --7-,- - an-y--- - - - ,n, a r - ee -a

e .

,y . . . Proposed Agenda - Diaolo

• 1/28/75 SUBCGMITTEE CAUCUS - CLOSED SESSION

. (15 min.) VIII. Systems Interactions (reference letter, dated 11/8/74. WRS to (PCLE/DL)

Huntzing)

Adjourn meeting at 7:00 p.m.

WEDN'ESDAY - FEBRUA RY 19, 1975 a

( 30 min.) 1.

Executive Session - Closed (8:00 a.m. 8:30 am)

' (30 min.) II. .Roactor A. Brief Description of Major Features / Comparison (PC6E) with Exis ting Designs B. ECCS/LOCA - Appendix K Evaluatiens. '

1. Unit 1/ Unit'2 Results - Comparison with Existing Design s

2. Limiting F calcula ted for Unit 1/ Unit 2

3. Status /Sch dule for Completion

, , , C.

Power Distribution Control Method - Ex-core /APDMS/

COAC D. (PCE/DL/W) i E.

Significant changes in Design from CP Stage Sta tus of 17x17 Ver ifica tion / Review (15 min.) III. Electric Power Systems (One Line Diagram)

A. Off site Power (PC&E)

B. Onsite Power i

C.

' Emergency Power

D.

Reliability Considerations - Diesel Qualifications (15 min.) IV. Emergency Plan '

(PC&E)

(15 min.) V. Industrial Security - Closed (PC&E)

(?? ) VI. Resolution / Status of Generic Items A. List ?? (PC&E)

B. List 77 C. List 17 (20 min.) VII. Plant Items A. (PC&E/DL)

Brief Description of Plant / Layout C. Major Design Changes Since CP Stages C. Lessons Learned from Operati.g Experience /Related Design Changes VIII. Lockout of Povor-Operated ESh Valves (PG6E/DL) i Adjourn !!coting at 2:00 p.m.

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DCl4SURE NO. 2 ATTDENCE LIST DIAB 14 CNNON ACRS SUBCONITTEE il'ETD:3

. ACRS Dr. D. OPrent Dr. S. Bush

_ACPS CONSULTN ES

Dr. B. Pagen (StanfoM University)

Dr. G. Thompson * (Stanford University)

Dr. M. Trifunsch (California Tech.)

Dr. M. White (University of Massachusetts)

Mr. K. Steinbruggen (University of California)

Mr. J. Eberso.enn (on leave of absence from T/A)

Mr. E. Koffran (los Angelt.s Water & Pcs'er Departnent - Retired)

Dr. S. Siegel (Atomics Inte rational - Retired)

ACRS STAFT J. Conran I

e PACIFIC GAS AND ELECTRIC CCt9MN (PGSE)

W. J. Lirdblad J. B. Hoch R. V. Bettinger W. X. Brunot H. J. Gamly E. P. Wollak V. J. Ghio D. Nielsen R. A. Young R. R. Fray J. C. Carml1 J. R. Herrera .

P. A. Crane

• D. Sullivan R. Ramsay J. Shi.ffer R. Patterson Pt000314Y

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.2-PGSE C0!15ULTAllTS Dr. R. Jahnch (Stanford University)

Dr. S. W. Sntith* (University of Washirgten)

. Mr. D. H. Ha::tilten* (Earth Sciences Asscciates)

D. J. A. Blt:ne* (John A. Blt:ne & Associates, Engineers)

R. Gallagher* (John A. Blt:ne & Associates,

• Engineers)

D. Jhaveri* (John A. Blu.T.e S Associates. -

Enginee.ts)

Dr. L. S. Hwang* (Tetra Tech, Incorporated)

WESTI!GHOUSE Dr. D. W. Peacock Dr. T. C. Essel. Tan Dr. Chi-Wo.n Lin

• Mr. J. W. Dorrycott Mr. A. J. Abels NRC - ST/JT T. J. Hf 7 ns I

j D. P. Allison O. D. Parr

! R. C. DeYoung*

l J. C. Stepp*

R. B. FtMullen*

I R. B. Hofmann* I i W. P. Gamill*

H. R. Denten*

L. G. Hulman*

M. L. Fliegel*

K. K. Kapur*

L. Shao*

J. R. Tourtellotte*

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USGS J. Devineh F. McXeewn*

H. W g ner*

R. Yerkes2i G_D!EPAL IUE:.IC _

Attendan:e by the general public rangad bei: ween 10 and 30 people, dependi. g cn the particular subjeev beirg disussed.

• Denotes anendahet ut fiist day cidy.

• • Denotes attr.me.nce en secend da/ only.

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Distributio[n:

Docket File R. Tedesco

<P NRC PDR V. Stello Local PDR R. Maccary NRR Reading (M. Groff) H. Denton R. DeYoung V. Benareya V. .%:c m C. Lcng' D. Skovroit J. Kastner D. Muller G. Lainas R. Denise D. Poss K. Goller T. Ippolito G. Lear J. Knight W. artler S. Pawlicki J. Stol: L. Shao R. Clark B. Grimes T. Spies W. Ga r.ull D. Vassallo R. M11ard K. Kniel P. Fine O. Parr T. Novak A. Sc.hwencer M. Spangler R. Schemel EP Project Mr.ager - W. Ross D. Ziemann Attorney, ELD p P. CblFns- E (3)

R. Purple V. Wilson G.. Knighton KRS (14 )

G. Dicker Project Mana6er - T. J. Hirons B. J. Youngbiccd LWR l-3 Fehng W. H. Regan, Jr. LWR l-3 File R. Vollmer D. ?. Allison W. Housten J. C. Stepp S. Vega R. B. Mc.t llen R. W. Klecker R. B. Ibfmann F. Schroeder L. G. Halman K. K. Kapur M. L. Fliegel J. R. Tourtellotte 1

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^ IHM 'mANSCRIPT HELTIM3 SlMMRY DESCRIPTION w <>.- 8 PAGE PAGE ADDRESSED TO @

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1. 160-161 A~ 0 Will the turbine valves close reliably Applicant on loss of power during an earthquake.

2. 162 10 Justify in detail 0.4g in light of Applicant & I e .

. appamnt disempancies. Staff 3.

162 10 ht would be peak accelerations Applicant E with other current methods. Staff 4c 162 - 10- What would be the effect on the Applicant E plant of a small magnitude carth- Staff f

gr

. quake with high accelerations. ,

'5 . 163 10 When the peak acceleration his been Applicant E

..y' determined would it be possible Staff to derive a confidence level for it.

.' 6. 163 10 What are the maximum observed and Applicant c

~ , predicted intensities at this site Staff and the peak accelemtion resulting frun these. .

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164 10 Provide USGS open file report Applicant E 74-272 to ACRS. Staff

8. 165 -

If any additional interpmtationa Applicant c of data exist provide and/or Staff describe to ACRS.

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'Inclosurt No.1 -

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IIDi TRANSCRIPr HEETING SLM1AIOf DESCRIPTION ADDRESSED TC I PAGE PAGE -

,- - .i 9 .165 (j.5 l 10 Consider the possibility that the Applicant I newer carthquakes do more to the Staff

'l structure than the origiwil design,

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Reservations on using Parkfield earthquake.

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165 .

11 ht kind of errors can arise in sair.maic design analysir..

Applicant (

Staff p

. I 11 , 166 11 What are the errurs going; frun 1

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dimensional seismic model to finite elet analysis.

Applicant E (

Staff JM- / '

12. 166 11 Why do the two new spectra pzuvide Applicant E

, . adequate assurunce. Staff A -

13 . 166 ~

11 How does the staff decide what Staff [pg' ..

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. . constitutes an adequate audit #,

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.* cet ami==mic design.

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4'. - 169 11 Response of instruments and equip- ' Applicant 172 - -

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ment to higher accelerutions at -

173 -

higher faquencies.

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15a 196 12 Full scale shaking of staw:tures.

Applicant - l 204 -

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ir scatt sincet . s AN raascis::. catironsia 94tc6 . (4i 3781 4::: . t<<r 9:o 37: esar February lv, 1988 tR iEDOM OF INFORMAM ACI REQUEST f0.T4 ///

1 Director, Of fice of Administration U.S. Nuclear Regulatory Commission d k" /7'b E ,

Washington, D.C. 20555 '

Re: Freedom of Information Act Recuest Pursuant to the Freedom of Information Act (5 USC 552 et seq.) and implementing regulation 10 CFR 9 subpart A, we  ;

request that you furnish the documents identified in the l attached FOIA request.

In accordo. ice with the provisions of 10 CFR 9.14, we are l prepared to pay feen necessarily incurred in responding to I this request.

If you should have any questions regarding the request, please contact the undersigned at telephone number (415) 768-4917. Your prompt attention to this request will be greatly appreciated.

Very truly yours, f

Mary Eliza Stewart MES: mat Enclosure l

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t FOIA REQUEST NRC 1

1. Item 4 on p. 11 of the March 18, 1975 NRC summary of the ACRS Subcommittee Meeting held on February 18-19, 1975 on Diablo Canyon (see Attachment 1 to this FOIA) lists an ACRS subcommittee question on adequacy of audits. This question was to be answered by the NRC staff.

2. Page 2 of Attachment 2 to this FOIA request is entitled "Enclosure 1" and includes some informal notes on the status of responses to this and other ACRS subcommittee questions. These notes indicate that the response to the question described above was "done."

3. Please provide:

(a) a copy of the entire document that includes Enclosure 1 (Item 2 above); and (b) any documents that provide the response to the ACRS subcommittee question described in Item 1 above.

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PA0ll IN NEER

///7AU8A[N/~/ HAR,18 1975 EPW s DIAko CANYON SWN H10 MAR 2 i 1975 g JM4-50-275 AND 50-323 N - TE7,gs

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APPLICAtTI: PACIFIC GAS AND ELECTRIC COMPANY (PGSE) -

DIABLO CANYON IPJCIIAR EU4ER STATION, UNITS 1 AND 2

' FACILITY: 18-19, 1975 SUtt!ARY OF ACRS SUBC0ttfITTEE MEETING HELD ON FE

. . An ACRS Subccanittee Meeting reganiing the Diablo Canyon Nuc 18-19, 1975.

Station was held in San Luis Obispo, California on February A complete

'Ihe agenda for the meeting is attached as Enclosure No.1.

1 list of attendees is given in Enclosum No. 2.

i i Introductory State ~ent by Acolicant_

The meting opened with an introducton/ statercat by the applica Construction included a status report on constmetion and fuel Iced.

has reached approxi~.ately Shiprent 90% and 50% completion o of fuel to the site respectively.

1975, and Unit 2 in late sunmer of 1976.

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! for Unit 1 is scheduled to begin in June of 19'.5.

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Outstandinc Iters in Safety Revie't j f the outstanding items in the f

'Ihe staff then stmarized the status oThese items had been previously st=arized Diablo Canyon safety review.in 31, 1975.

Section 22 of Supplerent No.1 t i h Supple ent was issued on January

{ of these iters are our evaluation cf the c.arthquke potential or t e Hosgri Tault, effects of tsunr.is caused by near-shorn generators, 'Ihe seismic qualification of electrical equignent, DIS and A'NS.

status of each item was reviewed in detail, with the staff indicatire, i where infomation from the applicant was outstanding and when resolu

' of each item was likely.

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Sandra A. Silver int, a staterent was trad into the tycord by Sandra A. Silver, nt of San Luis Obispo County and an intervenor in the Diablo a pmceedings. Ms. Silver cc:mented on sevetul issues involved Jie Diablo Canyon safety review, and expressed strong objections to

.e location of the plant in San Luis Obispo County. Dr. O' c ent indicated that her cements wuld be passed on to the Full ACRS Conmittee. ,

Geolocv an'd Seiscology he applicant then began his pmsentatien an Geology and Seiscology.

'Ihis presentation consisted of four sepa ute talks by PG5g consultants:

4 (1)

/ Dr. Richard Jahns, principal geologist since the beginning of the project, discussed the geological background and the developcent of the geology report for ;he site. He emphasized

f. the general mgionalization of the site and its location in California geology.

(2)

Mr. Douglas Ha.Tilton, geology consultant, dealt specifically i

with the offshore seismic interpretation progra.Ts.

! (3) l Dr. Stewart Smith, the seisrologist of record, discussed e>isting i seismic data and a detemination of the postulated earthquers I that should ba considered in the design of the plant.

(4)

Dr. John Blume, structural engineering consultant in the area of carthquake engineering, discussed the methcds used for developcent of seismic input on events into vibratory grcund notion.

Dr. Jahns concentrated on t,ri areas in his presentation: (1) a brief sumary of the early geologic investigations at the site, with emphasis on the problem of potential surface faulting; and (2) a st.

regional tectonic characteristics of Southern California that areury of partinent to appraisals of the site. 'Ihe exploration of the site as far as artificial exposures w2re corcerned was aired at a detailed appraisal of the sub-horicontal contact between the ulve cut bedrock surface and the overlying rarine terrace deposits.

can be dated, it would then be possible to de.~nnstnate that if faultsSince these d were found in the bedrock, and these faults did rot disturb the overlying dated raterial, then an age cailing could be ir: paced on the latest PC000314Ae

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novement of these faults. As a msult of the extensive tunching ard excavation program which was corducted, it was concluded that potential surface faulting need not be considered in the plant design. With regard to the regional situation, Jahns emphasized that the different

. major faults nust be evaluated in the context of their own physical characteristics, continuity, segment length, etc., and also with

, mgard to their positions and behavior throughout different parts of geologic time. He indicated that the San Andreas Fault was clearly .

the dominant feature involved, but also discussed the importame of the Sun Nacimiento fault zone. He concluded by stating that for i the faults in this agioral setting, it would seem significant in

.. f - considering the mspective roles and' orders of significance to consider them nest specifically in the context of the past five million years since that is basically what is involved in appraising their present and potential future activity.

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! I:oug Hamilton began his presentation by discussing some of the work

. that has been done in surveying the offshore geology. He indicated

'; that there are tw elements of this surveying: (1) seismic reflection profiling; and (2) gravity survey and rapping program. There have been four different surveys applicable to the regien offshore fmm the Diablo Canyon site:

(1) USGS Bartlett emise in 1972 urder the direction of Ely Silver; (2) USGS Kele:: survey in 1973 urder the direction of Holly Wagner; (3) PGSE sponsored work in 1973-1974 by the fim of Bolt, Beranek ard Newmn of Houston; .

(4) PGSE sponsored work in 1974 by the fim of Aquatronics, Inc.,

j of Houston.

i Hamilton used detailed maps and track charts to irdicate the amas of coverage by each of these surveys; he stated that the interpretation of the offshore profiling involved integration of data fmm all four of these surveys. These data sure discussed in considerable d' : ail; the discussion also included a detailed interpretation of the 3csgri Fault. He described the Hosgri Fault as continuing as either one or a group of two or three breaks, and tmced the fault from near Point Sal rorthward to the vicinity of Cape San Martin whem the breaks die out. 7he plant site is about two and a half miles to ^.he irner breaks of the Hosgri Fault at its neamst point of apprmch. Hamilton L

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then turned his attention to the compilation of the gravity survey data.

The mp gave gmvity aromly values for the offshore ama ranging fmm Point Conception up the coastline to a point amuM Cape San l'artin.

He emphasized the importance of this mp, in that it gives definite

- indications of rajor structuml features that have been mpped irdependently by other means, e.g. , the Santa Lucia Bank and Ibsgri Faults. Hamilton concitried his discussion by sumarizing the major features of the area, including the large offshore Santa Paria Basin, ,

the lesser or folded basins, including San Luis Obispo syncline, the Pisco syncline, the area of the Santa Maria Valley and the onshore Santa thria Basin which lies generally south of the Santa l' aria

. Val. ey dowTi to where the' transverse ranges ccce up south of lompoc.

Thi stmetumi disturbance of these includes very large faults which

. ave very pronounced gmvity expression. 'Ihese include the Santa Lucia Rmk and San Simcon Faults, the Faults of Rinconada and the Sur Nacimiento system, and to the south, the faults of the transverse ranges system including the Santa Ynaz and a system of faults which has o specific rare that branches off fmm the Santa Ynez and then heads up toward Point Sal. Lesser faults are also shoto in this gravity expressicn, including the Hosgri Fault which does have local gravity expmssion, but clearly rot expression which is comparable either to the Santa Lucia Pank cr San Simeon Faults and to other i faults nupped enshore which include the Edra, the Pisco, ard related faults in the ground east of the San Luis Pange area.

Seveml questions were asked regarding Ha:nilton's presentation. Dr.

l Page asked whether there was fim evidence that the Hosgri and San i

Sireon Faults are not connected? Hamilton discussed the data in

the region of the proposed cornection; he felt that the evidence

!' is gcod that they are not all or.e continuous system, although he qualified the staterent by saying that both faults have to be considered i part of the system of faults on the easterr. bourdar/ of the Santa Miria Basin. Dr. Trifu:uc asked what Hamilton's speculations would be regarding the general sense of notion, the amplitude of notion, and the effects of these notions on the mjor faults that wert discussed? Ramilton responded in light of the Ibsgri Fault, and

. indicated that the Host,ri might be considered capable of a few feet of roverent, although he did rot specify whether that coverent would be vertical or lateral.

Dr. Stepp of the NRC staff then corrmented on the informtion presented.

He indicated that the staff had reviewed the raterial presented, and that additional infomstion on the subject had been requested from the applicant. 'Ihis mquest included questiens on the mlatienchip PC000314C-

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of the Hosgri and San Simeon Faults, a role detailed documentation of the structuml relationship of these faults in their assu ed ama of appmach, and a discussion of the st2Netural relationship of the Hosgri Fault to the transverse ranges faults. 'Ihe staff also asked for a discussion of the magnitude of earthquakes that one might expect on faults within the San Andreas Fault System that have different oMers of structural significance. Fimlly, additiomi

' documentation was requested reganiing the location of the 1927 .

earthquake that occurred off Point Conception. Stepp indicated that the staff hoped to complete its review of this material in May of this year. F. McKecwn of. USGS concurred with the staff's corrents, and e;;hasized that the relatior. ship of the southern end of the Hosgri Fault to the transverse ranges could be extm~ely impot tant in 1ccating the 1927 event.

Dr. Okrent then asked hcw much of the offshore info ration that is reported new was available in sufficient scope in 1967 to pruapt sonecne to look for the structures roa being reported and discussed?

Dr. Jahns irdicated that the potential existence of the Hosgri Fault was suspected in 1967, but that no detailed offchere sub-bottom data wem available. The applicant emphasized that the geological studies perferred prior to the constmction pemit review were quite extensive, and that there was no question in their mind that a very i

complete state of the art investigaticn of the site had been perforced, i

Dr. Smith began his presentatien by discussing the earthquakes which had been postulated as design basis events for the plant; he emphasized the levels of conservatism that had been e ployed at the construction i pemit stage, e.g. , the assu~ption of an earthquake umssociated with a fault occurring directly beneath the plant. Smith indicated that

' the discover / of offshore faults in recent years was not mally a surprise, and that events subsequent to the initial amlysis at the CP stage have borne out the wisdom of the very conservative approach that was taken in considering that ca% quakes of the size postulated could occur as close to the plant site as was assured. He further stated that, based on Hamilton's interpmtation of possible notion on the Hosgri Fault, the gmund ration produced by an event of this size, at a distance of three to five miles at closest approach would certainly fall within the envelope of the kinds of gnourd rotion that have been proposed for the site. With regand to earthquakes on the offshore faults that have been analyzed, Smith indicated that these events have cc .tained a large component of vertical slip. He then discussed specifically the 1927 earthquake that was centered PC000314t

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off Point Conception; analysis of the data indicates that the aftershock region had to be substantially closer to the shore than the min shock location given by Byerly in 1930. However, Smith stated that he cannot clearly associate this event with one of the pmsently rapped faults,

. although it is his opinion that the most likely association is with the transverse mnge strtetures.

,' After several questions from the ACRS consultants regarding location ,

and depth of the 1927 event, and postulated earthqtukes on the Hosgri l Fault, Dr. Blume began his presentation by reviewing the four specific fault-earthquake situations which were postulated for the design of ,

the plant' He eghisized that, at the CP stage, very few methods were available for converting tragnittde and distance into site acceleration, '

and that site or peak acceleration was only one consideration that was 4

. used in the design. Other equally inTortant considerations were the j damping factors assumad for various structures and systems, the duration of the shaking, the probability of peak acceleration, given a certain

, i earthquie, and the probability of the spectral response diagram, given that peak acceleration. Blume discussed in detail the rethods tnat were used for estimting site acceleration; he indicated that the principal one employed was the Site Acceleration Magnitude (SAFD or -

Blure Method. After a detailed discussion of the SAM nethod as applied i to the four earthqtake situations nentioned above, Bltrre stated that  !

i he is pleased with the fact that the rethods used nearly 8-10 years  :

j ago at the CP stage compare extremely well with those in use tcday, 1 , e.g., those proposed by Snauble & Seed, Clotd 6 coress, and Donovan.

i Blume then discussed the recent analysis that was perfonnad based on I components of the Parkfield-5,1966 and Castaic,1971 carthquakes, i;

cach normalized to a peak ground acceleration of 0.5g, rather than j the 0.4g that was used in the crigiral design. He also m ntioned  ;

l' the Koyna transverse earthqtake in Irdia as being close to the situation

' at the Diablo Canyon site; an acceleration of 0.49g was observed fmm j this event.

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Dr. Trifume asked a question regarding the SAM method as described in Dr. Blure's paper in the 1965 World Conference Proceedings. Trifunac indicated that the use of this nethod by Bltrre appears to result in accelerations which underestimte all present available data by a factor of 0.5 to 0.8 on the logarithmic scale. After a lengthy discussion, Bitne agreed to get together with Trifume in an attent to resolve

. this apparent discrepancy.

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MAR. I e 1975 Dr. Kapur of the NPC staff emphasized the part played by damping values in the detemimtion of msponse spectra. He indicated that the damping

.. values used by the applicant were very cvnservative, and that the staff considers the msponse spectra calculated by the applicant to be quite conservative.

Dr. Okrent the: asked the USGS to elaborate on their statemnt that a ~

design acceleration value of 0.5g is not adequate? Jares Devine of USGS indicated that this staterent was maant to leave the issue open because he did rot feel that all questions had been anske n d at this paint. Devine stated that r 3 cent work by Dr. Smith concerning the location of the 1927 event. along with sore unpublished work by the USGS, indicate that ther. is still profitable inforration available

- concerning that earthquake which could alter the obligation to put it on the Hosgri. He also e phasized the irportance of the ranking of faults with regand to the resolution of this question. Okrent then asked what appmach the USGS wculd take regarding the ratum of the Hosgri structure if the 1927 event had never occurmd? Frank PcKecun of USGS msponded that there is no definitive evidence to tie the Hosgri and San Sireon Faults together, but that the possibility cannot be ruled out entirely. He indicated that it is very difficult to assign a given size earthquake to the fault because you are not j dealing with a single continuous bmak; it consists of mny, rany j breaks. Dr. Trifunac asked whether the applicant's four pmposed i design basis earthquakes could be considered reasonsble if the 1927 l event were eliminated? Devine replied that he felt that all four

! wem reasonable at the tire of the CP, and that he still feels that they am reascnable with a proviso on carthquake D (the event umssociated with a fault), that being taat the Hosgri be examined rare carefully l after the applicant resp:nds to the staff's recent request for I

, additional infomation. He irdicated that this inforration will helo '

I to better estirate the raximum carthquake that cculd cccur on the

'. Hosgri Fault which in effect row controls the undesigrated earthquake D.

Dr. Okmnt asked the stiff whether the acceptable seistic design criteria for Diablo Canycn 1 and 2 would be the sare for additioral units, if such were proposed? Dr. Stepp irdicated that the staff's seismic design criteria have constantly been upgraded as our under-standing of the problems of earthquakes and earthquake spect:u properties change. He stated that we would always consider the prob 1ble taxiru~t earthquake for the site in ou" evaluation, mgardless of whether the plant was partially built or not. Dr. Shao emphasized that the PC000314 F

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staff will consider all steps in going from the g value to response spectra and damping values, including the nethods used, and then a decision would be nude reganding the adequacy of the seisede design.

After core discussion, Shao indicated that if the g value holds at 0.5, and the applicant has employed the criteria and m2thods which have been stated, then the plant is pmbably adequately designed for seismic loads. Dr. Okrent then asked what probability per year of .

safely shut-ting down the reactor in the event of an earthquake, that the staff is seeking for Diablo Canyon? Dr. Danten replied that the staff does not use a pmbahility appmach in selecting safe shutdown earthquakes'(SSE). He stated that the Corrission's criteria, as set forth in Appendix A to Part 100, pmvide a frarework to work in to arrive at an SSE; we then have to couple that with the design approach and the design of stmetures and components in order to arrive at an evaluation of adequacy of the seisntic design.

Dr. 7horpson pointed out that, after all the discussion that had transpired, the qu2stion of whether the Hosgri Fault would be expected to exhibit pnadordmnt strike or dip slip had not really been answered. Holly Wagner of USGS commented in detail on the findings of his survey, but did not reach any fim conclusions regarding the preferen e for strike or dip slip.

Seismic Desien i Mr. Wollak of P3EE began the session on seismic design with a presentation on the design criteria for the mjor components, and how Dr. Blune's criteria have been implerented. Wollak stated that the seiselc a mlysis 1 of Scisnic Category I structures, systers, and corponents is based on the input free field grcund notions and the resulting response ,

spectra for the operating basis and safe shutdcwn earthqtukes. Four I

dyrmic tethods of seismic amlysis were used

l (1) Tine history rodal superposition; 1

(2) Restense spectrJm rodal superposition; j l

(3) Response spectim single degree of freedom; and l 1

(t4 ) Method fcr rigid equipnent end piping. l After discussire, design procedures in detail, Hollak com2nted on sore recent work which was done to compare the safe shutdxn carthquake response of typical Category I struen:res, sysic~s, and com cnents to that which would be induced using nrAified input response s'pectra and PC000314 Gr

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I the damping values given in Regulatory Guide 1.61. 'Ihese modified input asponse spectra were derived from acceleration time histories l

. for ccmponents of the Parkfield-5,1966 and Castaic,1971 earthquakes, each normalized to 0.5g. The spectral content of these records is considend repmsentative of the vibratory ground motion expected at a site with foundation material similar to Diablo Canyon, and generated frem a nearby source. A comparison of these rrodified spectra with '

. the spectra and damping used in the SSE design confirms the seismic i design adequacy of typical Category I structures, systems, and components.

- Wollak concluded his presentation by stating that the seismic design j

,,*- basis for major plant structures and components includes significant conservatism in the form of design spectra (unusually rich in high frequencies), very low assumed damping values, and an acceptance criteria based on overall elastic behavior under seismic loadings.

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! Dr. Okrent asked whether a calculation had been done using 0.5g peak ,

acceleration and the response spectra and dar: ping values of Regulatory _

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Guide 1.60? Wollak replied that they had not done this. The staff

then eccmented on the applicability of the response spectra in 1.60,

! and also on the reasoning behind the selection of the Parkfield and  ;

Castaic earthquakes as comparisons for the Diablo Canyon site.

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. Dr. Okrent emphasized the importance of knowing, with scoe degree of (

. assurance, that all safety related structures  !

will be able to survive an earthquake of given, systems, acceleration, and ecmponents e.g.,

0.5g. Mr. Lindblad stated that once seismic design criteria were j chosen fer the plant, all structures, systems and components were  ;

designed to meet these criteria. He indicated that he feels that j there is conservatism in the overall design.

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- After additional discussion en loading factors and the different  !

seismic design situations where the OBE and SSE control the design,

Dr. T. C. Esselman of Westinghouse presented the seismic design i

criteria that were used for the primary loop components and piping.

He reviewed the trethods used for each ccmponent and for piping, and irdicated the margins that resulted from the analysis. Dr.

Okrent asked whether the staff reviewed the seismic rmdeling of j various components in the prinary icop. Dr. Kaour replied that 1 WestirChouse has documented many codes involving this rrodeling, l and that the staff has reviewed these codes in scme detail. The '

i possibility of failure of the turbine building (a non-seismic  !

i Category I structure), and the effect of such a failure on Category '

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I systems was discussed. The staff stated that all such systems in the turbine bui.lding had been adequately protected against such a failure.

With regard to this item, Dt. Bash asked about the supports on the valves, that in the cvent of loss of pcuer during an earthquake, v. tut is the reliability regarding closure of the valves? Westinghouse agreed to pmvide inforration in response to this question at some later date.

ACRS Questions Regarding Geolorv-Seisnology and Seismic Desien .

Follcwing.a short executive session, the recting reconvened, and the followir6 questions were raised by several of the ACRS members and consultants:

Dr. Trifunac (1) In light of previous discussions with John Blure, justify the apparent disc:vpancies in the relationships used.

.(2) Referencing questien 1, w'.ut would be the ca]eulated peak acceleration using other currently available methods?

(3) k?at wuld be the effect en the respense of the plant of a crall l ragnitude earthquake which prodaces very high peak accelerations?

i (4) When this peak ceceleration has been derived, would it te possible

to calculate confidence levels en this va_lue?

(5) h?at is the raxirca historic, as well as predicted, r:odified i Parr.ali intensity at the site due to any earthquake any place, and l what would be the peak acceleration resultira frcn it? l

! Dr. Troroson (1) He inquired alcut copies of USGS Open File Report 74-272. Mr. I Devine of USGS agreed to pmvide several copies of this report. I Dr. White (1) Provide additional c' idence to de.sostrate that the Castaic aid Parkfield earthquakes t raliced to 0.5g) reall/ luve lesser effects on the Diablo Canyon stn:ctures than the 01igind design earthquake.

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i Dr. Okant (1) What kind of errors can arise in the seismic design analysis?

- (2) What are the sources of error in going frun the earthquake itself via a one-dimensional seismic rodel to the finite elerent nodel?

(3) Assuming that some peak g value is adopted by the staff as adequate, justify that the calculations based on the Castaic and Parkfield

, spectra provide the necessary assurance.

.. (4) How d6es the staff decide what constitutes an adeq pte audit of i the seismic design analysis? (Refemnce the Appendix to Draft WASH-1400 which includes a partial design check).

Dr. Okrent asked the applicant and staff to be prepared to discuss these questions at the next Dichlo Canyon Subcomittee Meeting. (The last question is for the staff caly).

Seismic Desim (continued)

Mr. D rrycott of Westinghouse then presented e.e design criteria and

. qualification requirements fer safety related instru untation. He listed the instment control electrical equipr.ent that had been walified in testing prtcrams; this equipment was tested in full-scale testing ,

progra s and qualified to design acceleration levels. Dr. Okrent asked

. i.f an earthquake with a larger higher frequancy ccrgenent thin the one analyzed would appreciably affect the performnce of the instru-entatien? i Af ter some discussion reganding the effects of damping, etc. , 0) rent i asked the applicant and Westinghouse to look into this ratter. Dr. Kapur i ccemented that equipment at higher elevations in the plant does not  ;

I experience the very high frequency Ocep:nent, and so the problem is not I co severe. Mr. Ebersole pursued the discussion with Irgard to possible o:ntact chatter in switches, etc. Darrycott responded that Westinghouse is pursuing a failure mcda and effects analysis with Irgard to the resolution of this problem. The staff incicated that they hoped to have the issue of seismic qualification resolved prior to completien of the Diablo Ca:ryon review by ACRS. With regard to qualification, Dr. Bush brought up the possible interactive effects of sais-ic ana enviterrnental qualification; } e asked if any werk had been done in this area? After ocme discussion, it was agreed that this problem had not really been addressed.

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Dr. Bush then brought up the subject of experimental confirmation of ~

vibration characteristics of major reactor ccrnponents, and the response of safety instrumentation to seismic loadings. This was an agenda item for this meeting as well as having been cited in the ACRS CP letters for both Units 1 and 2. Mr. Lindblad indicated that a number of programs have been instituted in response to this concern:

s (1) Equipment qualification dynamic tests, as discussed by Mr.. .

Dorrycott.

(2) Dynamic tests of expansion anchors (tests sponsored by FGSE M at,the University of California). ,

j (3) Component tests conducted at Indian Point 2 and San Onofre on 1 components similar to those which will be used at Diablo Canyon.

I With regard to item 3, Dr. Lin of Westinghouse discussed the i applicability of these component tests to Diablo Canyon. He first discussed in detail the seismic qualification of instrumentation, in response to earlier questions. He then indicated that vibration testing of the reactor coolant loop and steam.. generator had been l performed at Indian Point 2. He indicated that data were available i fmn San Onofre, both frun shake tests and fmn effects of the  !

San Fernando earthquake. Lin also discussed some full-scale testing on a Westinghouse reactor in Japan.

1' (4) Testing of rrodels of pipe and pInssure vessels for seismic damping characteristics (tests sponsored by PGSE at UCIA).

j (5) Installation of plant seismic instrumentation to record the g small earthquakes that may occur during the coming yearc of

operation, t

l Dr. Okrent asked whether PGSE had any plans for full-scale shaking of the Diablo Canyon Plant? Mr. LindblM replied that they did not, and that they felt that the conservative daeping assumed in the design provided sufficient margin such that full-scale shaking to repnaduce the natural

, period of vibration was not really neceseq. The staff added that

', unless one could simulate accelerations close to the SSE, e.g. , 0.4 to 0.5g, the benefits of such testing muld be small. The point was also made l

. that artificial testing to such large accelerations m uld be extremely  ;

difficult. )

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( ( MAR.I G 1975 Seismic Scram The last agenda item of the day involved a discussion of seismic scram.

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Mr. Lindblad indicated that PGSE had reviewed the recent Liventore report on this subject; he stated that the report leaves mny questions open, and that at the present time, PGSE believes that an autcmatic trip of

- - the reactor at the onset of an earthquake does not necessarily impmve the safety situation. Dr. Okrent asked whether the applicant had prepared some kind of list detailing the good and bad featums of a seismic scram?

Mr. Lindblad stated that they had done this at various times, and that on the bad side, such a scram introduces a non-standarti condition for the reactor, a transient involved in shutdown, loss of one of t le sources of power, and an additional need to monitor a changing ope: ation in the plant on top of the stress of the earthquake itself. Dr. Okrent then asked whether PGSE had evaluated the plant to see what level earthquake would lead to trip, whether you wanted it or not? Lindblad said they

, had not, but that he would esti ate something of the orxier of a 0.lg acceleration value. This could be a reactor trip, turbine u'ip, or i perhaps some other component, and would not necessarily initiate an automatic reacter shutdown. He added that he did not feel that it was good practice to shut the plant down for any earthquake, only for those which are potentially dam ging to the plant; he did not think that PGSE struld tolerate spurious trips of the reactor for small earthquakes.

Okrent asked about the possible merits of an early scram for an earthquake l which is going to cause a loss of coolant accident (1.OCA). Dr. Kapur stated that the nest important mason for having a seismic scram is that t if the earthquake is acccmpanied by a I.OCA, the peak clad temperature could be significantly mduced. He then considemd various postulated earthquakes. For earthquakes of the onder of the OBE, e.g. , slightly greater than or equal to the OBE, the operator is required to shut down the plant. For earthquakes much greater than the OBE, some damage will be incurred, but within the SSE, the plant is still designed

-l to be safely shut dcwn. For earthquakes in this range, there are other nonitoring systems which will trip the plant. Kapur also cited the i pmblems of spurious signals and unwanted transients in concluding that he did not feel that a seismic scram was desirable at this time.  :

, Mr. Ebersole raised the question of d-c powar supplies with regard to breaker closure or trip in the event of an eartrquake where one has

- generator trip. Then, what are the seismic qualifications of the switchgear and power supplies? Mr. Herrera of PGSE indicated that the I batteries for the switchyards have earthquake bracing and are designed l to withstand accelerations of at least 0.2g.

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( MAR. I 81975 Dr. Okrent asked whether one can engineer a seismic scram system with a high degme of aliability, e.g. , a reliability such that one has a probability of spurious. scram no larger than one in a 100 or one in a 1000 per year? Considerable discussion ensued on this item, with the

- general conclusion being reached that such reliability could pmbably be achieved if the threshald level were set far enough above the acceleration for the OBE.

After additional discussion of this item, the rmeting adjourned for

> the day.

.". Systems Interactions

'Ihe meeting for the second day began with the subject of systems inter-actions. The reference for this discussion was an ACRS let-ter from Dr.

i Stratton to Mr. Muntzing (dated November 8, 1974) titled, "Systems

! Analysis of Engineered Safety Systems". In this letter, the Committee

! indicated that attention to the evaluation of safety systems and associated equipment from a multi-disciplinary point of view to identify potentially urdesirable interactions between systems is becoming increasingly desirable and important. The letter then contains several examples to illustrate this there.

. After some general coments by Mr. Lindblad regarding the nature of the letter and its applicability to Dh N o Canyon, Mr. Ebersole posed a series of questions and situations regarding the applicability of this

! letter to the Diablo Canyon Plant. Ebersole had visited the plant the

- previous day. 'Ihese questions and situations am sumarized below:

i l

(1) In the event of fire in the turbine building, it appears that there could be ventilation pmblems in the 4 kV vital switchgear rcoms l and also in the diesel generator compartments. For the switchgear

. Incms, them is comen atmospheric coupling between these Irces, i and it appears then that there would be comunication between these

. roces in the event of a fire in one of them. In the case of the diesel generator compartments, if the generator end of the diesel is isolated, i.e. , the roll-dcre dcors are closed, one muld have '

a situation wher. the generator could recieve very little cooling,

causing a tempemture rise in that part of the room and a possible l overload condition and resultant a-c power outage. I l

(2) The plant has mny pairs of rotating shafts of various sorts serving

, different functions. These are typical redurdant configurations of services which are on line at all times (not engineering safety feature designs). Now,' suppose one postulates the failure of one PC000314g

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of a pair (say train A) which serves some specific function. Has the applicant examined the consequences if the alternate service, say train B, does not respond pmperly as a function of time? l Examples might be service functions which contml ventilating systems, l water supplies, etc. In other words, the interest here is the thesis 1 of non-response of backup tmins of active services, and a

- consideration of the time delay involved that .. tight be an abnormal delay rather than normal. An extension of this might be, if the .  :

backup service does not respond, what time is available to repair l the service or else pursue an alternate course of action? j

(3) The Rasmussen Report discussed the total loss of all a-c power, and included s me probabilities on the length of time before power might be restomo. With regard to this situation, has the applicant I considered this loss of power in light of the stoppage of rotating (

shafts and a Ex>ssible temperature excursion in the containment to I values of the order of 400-500 F? Mr. I.indblaa indicated that they 1

i had reviewed tnis general type of situation, and that the containment would not exceed its design temperature. He further added that with i loss of a-c pcwer, the containment heat input is reduced by about 85% because of the loss of the normal heat loads fmm the reactor  !

and the mactor coolant pumps. l (4 ) In the case of small LOCA conditions (larger than the charging pump capacity), one has depmssurization of the primary system. l For this situation, can the applicant describe the heat transport l

paths to the ultimate heat sink? Possible paths are the residual heat renoval system (but them is probably not sufficient' flow I hem), the ccmponent cooling wate system (which passes thmugh the

'. containment fan coolers) coupled with the auxiliary saltwater f

system, or natural convection in the steam generators. As a function of break size, what fractions of the heat are carried along these various transport paths to the ultimate hest sink? .

An additional question raised was, what will be the ambient temperatum surmunding the auxiliary feedwater pumps, as a function of time, in the absence of cooling and ventilation in these pump

rooms?

(5) For the auxiliary saltwater system, one of the auxiliaries is a

- comnen pair of sump pumps in the intake structure to pump out leakage, if necessary. 'Ihese pumps would be subnerged under a high wave condition. Khat are the critenia for the design of these sump pumps? In addition, the piping for the saltwater pumps is supported by connection to a non-seismic structure, P'C000314d i

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namely the condenser discharge conduits. The' idea of a seismic piping system anchored to a non-seismic structure appears to deserve some clarification. The coupling of the auxiliary salteter piping to the earthen fill and the building foundation ms also discussed.

(6) Again with respect to the sump pumps for the auxiliary saltwater system, it was mentioned that these pumps would be flooded under very high waves. Under this condition, would the integrated intake' of water into the louvres be such that the sump pumps would not be mquired in the short-term following this flooding?  !

.... -; l (7) 'Ihe cable link that supplies power to these sump pumps is an example  ;

of cabling which is intermittently subjected to fresh-and salt-water l flooding. Wnat qualification of this cable has been perfortred to l ensure its function under the conditions of alternate drying and  :

subnergence in either fresh-or salt-water? I

• I (8) With regard to the hot shutdown panel, is them a possibility that in providing this auxiliary function, you really have rot recreated a new scene for comon vulnerability of danuge? In other wrds, l

. is there really independence from the control room with regard to I this panel being a center of active functions?

! Each of the items raised by Me. Ebersole was discussed in considerable )

i detail. Dr. Okmnt asked both the applicant and staff to be prepared to i discuss and resolve any outstanding questions on these items at the next  ;

, Subcomittee Meeting. I Dr. Bush then raised the following two questions: I o

a. l j (1) Has the applicant considervd the problem of phosphate build-up with

.; regard to closure of valves on the turbines? 'Ihis question is ,

related to the response of non-seismic valves under severe seismic l shaking. Are there any reliability statistics regarding closure I of such valves under seismic loadings (when generator load has been l dropped)? Mr. Lindblad indicated that the Earthquake Engineering i Research Institute does collect infornetion of this sort. With regard to contacting the above-mentioned Earthquake Institute,

. Bush suggested that data from Alaska also be obtained, e.g. , data frun the 1964 Alaskan earthquake.

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(2) If you assume a failure of one of the inlet lines to the steam generator so that you have the full impact of the jet forces, as well as the jet forces frcm the exhaust from the steam generator, and then impose a seismic loading as well, does this

- situation fall within the design envelope?

(3) Dr. Okmnt asked that the staff reexamine in detail the nodeling of the primary coolant pump under a seismic loading, to te ,

- assumd that this nodeling has been done properly.

00 Mr. Koffman asked what accelerations might be experienced in

'. the control room for the design SSE acceleration of 0.14g?

Mr..Lindblad estimated between 1.6 and 2.0g, but indicated

. that they would look further into this item, lbffman stated

'- that this could be an additional argument for having a seismic scram.

f As a concluding remark to the general subject of Systems Interactions, i

T. Hirons indicated that the staff has had some preliminary discussions with ACRS as to how some of these situations should be handled. It ic

' planned that many of them can be incorporated into various sections of the Standard Review Plan. A special ACRS Subcommittee, with Dr.  :

Bush as chaiman, has been set up to begin reviewing some of these items l with the staff.  !

Electric Power Systems i

i Mr. Herrera of PGSE opened this subject with a presentation on the  !

l offsite pw.r system for Diablo Canyon. He stated that the inter- l l

connected PGSE 230 and 500 kV electric transmission systems will l

serve as a two-system source of offsite power for the Diablo Canyon j

- Units. The two generating units will be connected to the transmission

system by means of two 230 kV and three 500 kV lines emanating from their respective switchyards. These yards are physically separated and independent of each other. Each of the 230 and 500 kV lines

. supplying the Diablo Canyon switchyards have primary and backup protective relaying systems and autcoatic closing features. This  ;

will ensure fast and proper clearing of all electrical faults, and I will pemit automatic restoration of power firm the system if all  !

conditions are proper. Stability studies which have been conducted on the system indicate that the loss of any single generator in the system, including that for either Diablo Canyon Unit, while operating at full load, will rot adversely affect the stability of the remainder of the transmission grid. He concluded by stating that the design of the offsite po'er system meets the intent of General Design Criteria 17 and 18, IEEE Standarxl 308-1971, and Regulatory Guide 1.32.

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' .p MAR. I 81975 Seveml questions wem raised regarding the presentation on offsite power. Dr. Okrent asked if figures were available on system reliability that would provide a basis for judging the pmbability per year of losing all offsite power to the Diablo Canyon site? Mr. Herrera indicated

, that specific figums were not available. Mr. Ebersole asked if PGSE was taking any steps to upgrade the 1 cad rejection logic to pmvent cascade as the nuclear units come on to the system? Mr. Herrera indicated that they were. Dr. Bush asked if, under a seismic loading,

. can you bootstrap yourself to the turbine fmm a startup condition, -

as contrasted to a load mjection continuing operation? Mr. Lindblad responded that they could.

Mr. Nielsen of PGSE then made a presentation on the onsite power system for Diablo Canyon. ' his system consists of the output fmm the N main generator and an auxiliary power system composed of 12,000, 4160, and other low voltage systems. All auxiliary system buses can be fed from either the main generating unit or fmm the standby-startup offsite source. The emergency .nower system can also be supplied by the diesel generators. The engineered safety features and other emergency services are fed from three 4160 volt buses, each supplied by a diesel generator as well as by the nonnal offsite and main unit sources. ESF loads have been grouped to meet single failure criteria. Two diesel generators are sufficient to carry the emergency loads that are

, mquired for safe operation under nonral and accident conditions. One diesel generator is comon to both 'Jnits and is automatically transferred

! to the Unit which requires actuation of safety features. The onsite

', d-c power system consists of a 125 volt system. The system is divided into 3 gmups, and each battery has its own battery chargers and

{ switchgear. The batteries have the capscity to supply their loads i for the time duration required, even without allowance for the diesels imediately relieving some of the load.

. Dr. Okrent asked what happens if, in a seismic event, both reactors indicate that there is a IDCA? Nielsen indicated that whichever Unit receives its accident signal first will obtain the load fmm the swing diesel. After additional discussion, Okrent asked if anyone has

, looked at the reliability cf this situation, and does one have the necessary reliability? He further stated that he felt that the staff should 1cck in detail at the design of everything that one needs to function in oMer to get onsite power (both a-c and d-c), given an carthquake large enough to have a reasonable chance of losing offsite power. Finally, Okrent asked if the staff had considered the possibility of sequential effects due to earthquakes, a.g. , offsite power going off and on. Nielsen indicated, for the example cited, that once the diesels PC000314g

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- MAR. I 81975 come up to full speed (10 to 12 seconds), the offsit.a power source would be locked out. ft. Ebersole raised some additional questions regarding the change-over fmm offsite power to the diesels, e.g. ,

valve actuation. Nielsen responded to these questions for PGSE.

Finally, Ebersole raised the concern that the day tanks for all five diesels are supplied through a tu>-tank, tepipe, two-electrical pump fuel oil system, and that the state of the entire fuel oil

. system depends on getting power to these two small pumps 5hich

• nust cycle on and off frequently. Mr. Lindblad responded that the i

system msets the. single failure criterion, and that he fens that

, .m it is adequately designed to perform its intended function.

Lockout of Power to Motor-Ocerated ESF Valves s

A letter on this subject from Dr. Kerr of ACRS to it. Muntzing l (dated January 14, 1975) had been distributed earlier in the meeting to the applicant and staff. The letter raised sxe questions regarding the proposed lockout of power to the above-mentiomd valves. T. Hirons of the staff indicated that the position stated in the Diablo Canyon Safety Evaluation Report was unchanged at this tira. Mr. Lindblad stated that PGSE's position is that they prefer to maintain operability

.; of the valves frun the control rectn. '

Mr. Gomly of PGSE then began his presentation on this subject. He used a piping diagram to indicate the nine valves which the staff had flagged with regard to lockout of power. The nest important of these are the single valves from the refueling water stcrage tank to the

, safety injection and RHR pumps. Several questions were asked during i i the presentation regarding the size of the valves, valve opemtors, l annunciation of valve position in the control mcm, etc. Gormly ,

detailed the infonration that would be available to the operator to )

indicate that one of these valves was closed, and the steps that i the operator could take to open them. He indicated that they had made no ccraprehensive evaluation of the probability of spurious closure of one of these valves.

Several of the questions in the ACRS letter on this subject were then discussed in light of the Diablo Canyon design. These included an evaluation of the probability of a spurious signal, time interval required for reactivation of valve operator cfter loss of power, question of whether signal lights are lost when the circuit brster is opened, reliability of valve indicators, etc. The discussion concluded with it. Lindblad stating that the applicant would like additional time to consider scme of the questions in the letter.

'Ihe staff also indicated that they brauld respond later to these l questions. i pC00086 {

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MAR. I 8 1975 Miscellaneous Questions (1) Mr. Ebersole comented that the plant contains various hydrogen storage systems and lines throughout the plant. He brought up the general subject of hydrogen release and accumulation. Mr.

Gomly responded that they had taken this problem into account in designing the plant. With regard to hydrogen evolution out of the battery rooms, Mr. Nielsen stated that they had studied "

this problem in detail (partly at the request of the staff), and that,the analysis showed that it would take 28 days to accumulate enough hydrogen to approach the minimum explosive limit, assuming complete loss of ventilation.

(2) With regard to inservice inspection (baseline), Dr. Bush stated that the Units apparently meet the criteria set forth in ASME Section 11-1971; in this mgard, he asked how this compams with the 1974 code? Mr. Lindblad replied that the areas of non-

. compliance with Section 11 of the 1974 Code are very limited in natum. This question will be discussed in greater detail at a futum meeting.

(3) Dr. Okrent asked if in the routing of electrical systems, am

. seismic Category I and non-seismic Category I lines ever placed in the same cable tray or penetration? Mr. Nielsen replied that they are not. Okmnt then asked if there are possible nodes of J overheating for the non-seismic lines which could lead to a loss l

of penetration integrity? After some discussion, Okrent asked the applicant and staff to be prepared to discuss this item at the next meeting.

I

. Emergency Plan Mr. Shiffer of PGSE discussed the emergency plan for the Diablo Canyon Units. He indicated that in the development of the plan, primary consideration was given to the December 1970 AEC guide for the preparation  ;

of emergency plans for production and utilization facilities. The plan includes provisions for primary and alternate emergency control centers, notification of offsite state and federal agencies with msponsibilities during an energency, onsite first aid and decontamination facilities, and emergency radiological nonitoring equipment. Shiffer indicated that the plan describes a spectrum of accidents and the specific action levels to be taken for protective measures. In the event of an emergency, the San Luis Obispo County Sheriff's Department is responsible for coordimtion of any initial pffsite protective measures which may be required.

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, -f ", * (- MAR.I 8 1975 Dr. Okrent asked if PGSE had developed within their'own procedures, the specific infomation, the instrumentation, and the evaluation of these readings such that the operator or some other responsible person could detemine the nature of the events, given scme postulated accident? In the question he included the range of situations discussed in Draft WASH-1400. Shiffer replied that their precedures did include specific offsite nonitoring techniques, and procedures for interpretation of nonitoring results, e.g. , dose conversion tables. Considerable discussion '

ensued on this item, with Okrent emphasizing that early warning time of accident details was an important consideration in Draft WASH-1400.

Shiffer indicated that they have lcoked at high temperature radiation.

. nonitors inside containment, and also the possi;ility of a detector outside containment looking at either the extcmor concrete surface or at the liner at the contaircent equipment hatch. Ibwever, he questioned the validity of the interpretation of data wttich might te obtained from such instruments. T. Hirens indicated that the staff is still reviewing this question, both in a generic sense and specifically,

, for the Diablo Canyon Units; a draft Regulatory hide on post-accident instrumentation is currently being formulated. Okrent asked both the applicant and staff to be prepared to discuss this item at the next meeting. j l

Hiscellaneous Questions (continued)

R3 Ebersole coamented on the setting of valves in the RHR system,

. ',, the setting of valves to cope with the problem of pipe break l .idt regard to the paths which the water could follow. The question i on this pertained to the fairly simple instruction on an FSAR l drawing rega:Tiing adjustment and locking of a specific valve; Ebersole felt that perhaps this instruction should be expanded because of the number of possible fault situations. Mr. Lindblad replied that 1

indeed core detailed instructions are available for the operators.

(5) Ebersole asked about the intemediate connen C train in the ccmponent ecoling water system. If a major leak occurs in this C train, hcu do you prevent the operator fran simply drying up

. the system by pumping the alternate water inventories in the A and B trains into the sama fault? Mr. Gomly discussed the ronitors which would alam such a fault, and indicated that the C header would b2 isolated before any substantial loss in backup water supply had occurred.

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( IRR. I 8 1975 (6) Dr. Okrent asked whether the water hammer problems experienced at Indian Point 2 could be expected.to occur at Diablo Canyon? Mr.

Lindblad indicated that both Westinghouse and PGSE are currently reviewing the installed Diablo Canyon system to see how it compares with the Indian Point situation. Okrent further asked whether Diablo Canyon would be subject to the associated effect of containment liner heating that accompanied the feedster line rupture at Indian Point? Lindblad stated that he did rot think so, and that .

Diablo Canyon has a different feedmter design in that welds are mmoved from the immediate area of the liner plate.

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(7) Okrent postulated a IACA situation downstream of the steam generator where a two-phase mixture coming out of the vessel might lead to dynamic forres, particularly in the steam generator. He asked whether Westinghouse had done any further exanination of this ,

question? Dr. Peacock indicated that Westinghouse had completed

an analysis of the primary to secondary system interface in the

- steam generator; the analysis considemd the dynamic loads msulti ; from seismic forres, blov.down, and various load ccebinationa. One conclusion of the analysis was that slug flow wuld not be predicted by the blowdcun p rcess. Peacock j stated that this work ms documented in a WCAP report which was submitted to the staff over a year ago. C'eent asked the

staff to check on the review status of this report and connent

at the next meeting.

(8) Okrent asked if the staff had reviewed the kinds of insulation used at Diablo Canyon, and examined the potential effects of i

. insulation in the sump in the event of a IfCA? Hirons indicated that the staff had requested and received this infonnation l from PGSE, and that we were still reviewing it for acceptability.

Okrent asked for additional discussion on this at the next meetirg.

(9) Okrent asked if it was planned to mn the Diablo Canyon containment in the purge mode while the reactor is at pcrer? Lindblad replied that the purge valves would normally be closed. He further added

that the purge valves have the capability of closing during a IDCA.

(10) Okrent asked whether the question of unacceptable forces on the check valve seats in the secondary system had been examined?

Mr. Lindblad respondad that this question had been analyzed by l their consultant (Nuclear Services Corporation), and that the valve integrity ms found to ha satisfactory; he also stated that e

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i the staff had reviewed the analysis and found it to be acceptable.

Mr. Ebersole pursued the discussion with regard to one of the check valves experiencing steam ficw reversal; he asked whether the discs will survive the tremendous impact upon closure. Mr. Allison

. of the staff stated that the discs muld be defonrad tut not broken. In relation to this problem, Ebersole suggested that a pipe break in the vicinity of these valves could indeed effect the valve in the opposite line and possibly result in the blowdown

- of two steam generators. Lindblad stated that their analysis '

had shown that the second valve could withstand the failure of the first line. . Peacock emphasized that protective functions have be m' incorporated in the design to assure that only one steam reaerator blows down.

Conclusions Another Diablo Canyon Subcomnittee Meeting will be scheduled once the evaluat:'on of Geology and Seis:rology has been corrpleted. 'Ihe staff plans to complete this evaluation sceatime in Fby of this year.

' t~HL:L.) it . N&

b I Thomas J. Hirons' j Light Water Reactors l Project Branch 1-3

Division of Reactor Licensing

Enclosures:

1. Proposed Agenda

2. Attendance List 1

cc w/ encl

Mr. John C. Fbrrissey Philip A. Crane, Jr. , Esq.

Andrew J. Skaff, Esq. ~

Mr. Frederick Eissler Ms. Elizabeth E. Apfelberg Ms. Sandra A. Silver Mr. John Forster Mr. lornie Valentine Mr. William P. Cornell Mr. W. J. Lindblad i Mr. J. W. Darrycott j e

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DClDSURl'NO. 1

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c,. PROPOSED AGENDA

' DIABLO CANYON UNITS 16 2 SUBCO.'CilTTEE HEETING FEBRUAP.Y 18-19, 1975 - SAN LUIS OBISP0, CALIFORNIk PRINCI AL EPOKESMEN: W. J. Lindblad - PG6E, Projec t Manager Tom Hirons - Project Manager, Reg. Staff TUESDAY FEBRUARY 18, 1975 S

(30 min.) I. Executive Session - CLOSED -(8:30 a.m. - 9:00 a.m.)

(5 min.) II. Introductory Statement (PG6E) '

A. Brief Description of Site Location / Layout

. B. Construction Status - Units 162 C. Fuel Load / Opera tion Schedule (15 min.) III. Project Review Su,mmary and Status Report (DL)

A. Update on Sept., 1974 SER Unresolved / Outstanding Items .

i B. Resolution / Status'of ACRS CP Letter Items

. l (2 hrs.) IV. Site Characteristics L____._. , A. Geology /Scismology .

- 1. Detailed Status of DL Review '. (DL/USGS)

2. Applicant Pres en ta tions (PG6E) a) Basic Geologic / Seismic Data b) Vibratory Ground Motion

Surface Paulting

, d) Of f shore Scismic Interpretation Program

,' e) Determination of SSE and Seismic Design "g" Value for Site (30 min.) B. Tsunami Analysis (Model/ Analysis / Review Status) (PG6E/DL)

(15 min.) C. Tornado Design / Criteria

. 1. Applicant Presentation (PG6E)

2. Conformance to Current Criteria (DL)

3. Systems for Safc Shutdoun Weakly Protected (PCEE/DL)

(15 min.) D. Other Site Characteristics

1. Meteorology, Hydrology, Demography, etc.

(PG6E)

, (1 hr.) V. Scismic Design (PG6E/DL)

A. Design Critoria for Containment / Major Components B. Significant Changes in Design Since CP Stage

, C. Design Criteria / Qualification Requirements for Safety-Related Instr.

D. Stress Levels at 0.4g/0.5g/ Higher "g" values

l. Safety-Related Systems Most Vulnerable to Scismic Events E. Possibic Effect on;Non-Seismic Class I System Failure on Safety .

(15 min.) VI. Experimental Confirmation of Scismic Design Aspects ( iL6)

(30 min.) VII. Scismic Scram '

A. Existing Designs /Available Methods (PC6E/DL) .

B. Experienec 6 Reliability Considerations ,

i '

Pt000314W l

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• s,.. e Proposed Agenda - Diaolo .

,' . 1/28/75 SUBCOMMITTEE CAUCUS - CLOSED SESSION i

. .* \

.(15 min.) VIII.

~

Systems Interactions

• (PC&E/DL)

(reference letter, dated 11/8/74 WRS to Huntzing)

Adjourn meeting at 7:00 p.m.

~

WEDNESDAY - FEBRUARY 19, 1975 l

( 30 min.) 1.

Executive Session - Closed (8:00 a.m. -8:30 am)

' * )

y

(30 min.) II. . Reactor (PG6E)

A. Brief Description of Major Features / Comparison with Existing Designs

, B. ECCS/LOCA - Appendix K Evaluations. *

l. Unit 1/ Unit 2 Results - Comparison with 1 i

Existing Designs

} 2. calculated for Unit 1/ Unit 2

3. Limiting Status /Sch F{t;dule f or Completion

,, . C.

Power Dis tribution Control Me thod - Ex-core /APDMS/ i COAC D. (PCE/DL/W)  !

Significant changes in Design from CP Stage E. Status of 17xl? Verification / Review (15 min.) III. Electric Power Systems (One Line Diagram) (PG6E)

A. Offsite Power

, B. Onsite Power l C. Emergency Power j

j D. Reliability Considerations - Diesel Qualifications l

~

(15 min.) IV. Emergency Plan I (PG6E)

(15 min.) V. Industrial Security - Closed (PG6E)

(?? ) VI. Resolution / Status of Generic Items (PG6E)

A. List ?? -

B. List ??

I O. List ??

(20 min.) VII. Plant Items (PG6E/DL)

A. l Brief Description of Plant / Layout l C. Major Design Changes Since CP Stages C. Lessons Learned from Operati.g Experience /Related l Design Changes VIII. Lockout of Power-Operated ESF Valves (PG6E/DL)

Adjourn Meeting at 2:00 p.m.

PCr00314%

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s DCIDSURE No. 2 l

ATrDIDMCE LIST DIABLO CAIN0N ACRS SUBCOMMITTEE MELTIl!G ACRS Dr. D. Okrent Dr. S. Bush i ACRS CONSULTANTS Dr. B. Page* (Stanford University) ,

' Dr. G. Thompson ^ (Stanford University) l Dr. M. Trifunach (California Tech.)

Dr. M. White (University of Massachusetts)

Mr. K. Steinbrugge* (University of California)

Mr. J. Ebersole** (on leave of absence frun TVA)

Mr. E. Koffman (los Angeles Water S Power l Department - Retired)

Dr. S. Siegel (Atomics International - Retired)

' 1 ACRS STA'rT i

i J. Cortran PACIFIC GAS AND ELECTRIC COMPAtU (PGSE) i i

W. J. Lindblad j

J. B. Hoch R. V. Bettinger j

W. K. Brunot

,!: H. J. Gormly E. P. Wollak ch V. J. Ghio D. Nielsen R. A. Young R. R. Fray 3 J. C. Carroll J. R. Herrera P. A. Crane

• D. Sullivan I R. Ramsay J. Shiffer R. Patterson

?

i

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PC000314Y

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- l EGSE CONSULTNU'S Dr. R. Jahns* (Stanford University)

Dr. S. W. Smitho (University of Washington)

Mr. D. H. Hamilton * (Earth Sciences Associates)

D. J. A. Blume* (John A. Blume & Asscciates, Engineers)

R. Gallagher* (John A. Blume 6 Associates, Engineers)

D. Jinveri* (John A. Blume 6 Associates, -

Engineers)

Dr. L. S. Hwang* (Tetra Tech, Incorporat_ed)

. . -:f WESTIlEHOUSE

] Dr. D. W. Peacock Dr. T. C. Esselman Dr. Chi-Wen Lin

, Mr. J. W. Dorcycott Mr. A. J. Abels

, NRC - STAFF T. J. Hirons D. P. Allison O. D. Parr R. C. DeYoung*

J. C. Stepp*

R. B. McMullen*

R. B. Ibfmann*

W. P. Gamill*

H. R. Denton*

L. G. Hulman*

i M. L. Fliege1*

K. K. Kapur*

, L. Shao*

J. R. Tourte11otte*

-4  %

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_ . _ . . _ . _ _ ---__ - - - _ _ _ . . - . . _ . -. __ _. ._. -~ _ . _ .

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-3 USGS J. Devine*

F. McKeown*

H. Wagner * .

R. Yerkes*

GDERAL PUBLIC

.~ .

i Attendance by the general public ranged between 10 and 30 people : s

.. depending on the particular subject

• i being discussed.

4 I

l i

i

• Denotes attendance on first day only.

j ** Denotes attendance on second day only, i

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Distributicn R. Tedesco p7 Cocket Fil NRC PDR V. Stello Ircal PDR R. Mu:cary NRR Peading (M. Groff) H. Denton R. DeYoung V. Benaroya V. Itore C. Img' D.~ Skovholt J. Kastner D. Huller G. Iainas R. Denise D. Poss K. Goller T. Ippolito G. Lear J. Knight ~

W. Butler S. Pawlicki J. Stolz L. Sluo R. Clark B. Grimes T. Spies W. Gamill D. Vassallo R. Pa11ard K. Kniel P. Fine O. Parr T. Iovak A. Schwencer M. Spangler R. Schernel EP Project Manager - W. Ross D. Ziemann Attomey, EID #

P. (bilins- II (3)

R. Purple V. Wilson G. Knighton ACPS (14)

G. Dicker Project Mar.aSer - T. J. Hirens B. J. Youngblcod IRR l-3 Feading W. H. Regan, Jr. IRR l-3' File R. Vollmer D. P. Allison W. Housten J. C. Stepp S. Varga R. B. McMulle.1 R. W. Klecker R. B. Hofu nn F. Schroeder L. G. Hulman i K. K. Kapur M. L. Fliegel J. R. Tourtellotte 1

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. AdowlV.l~ G & hk[8' 87 5 'ACRS Oudcomm7'=" .

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,1.Di 'IFANSCRIPT PAGE MEETING SutMRY PAGE DESCRIPTION ADDRESSED TO f

1. 160-161 ,IO Will the turbine valves close reliably Applicant on loss of power during an carthquake.

-l 2. 162 10 Justify in detail 0.4g in light of Applicant E apparent discrepancies. Staff What would be peak accelerations

3. 162 ,

10 Applicant E 1 e with other current methods. Staff Y 4< 162 - 10- -

What would be the effect on the plant of a small magnitude carth-Applicant E f-

\

Staff

. quake with high accelerations.

. 'S . 163 - 10 When the peak acceleration has been Applicant E

- ..y ~

determined would it be possible Staff to derive a confidence level for it.

.' 6. 163 10 What are the maximtm observed and Applicant E predicted intensities at this site Staff

~

and the peak accelcrution n::sulting frun these. .

7. 164 10 .

Provide USGS open file report Applicant E 74-272 to ACRS. Staff

~ 8. 165 -

If any additional interpretationa Applicant E

. of data cy.ist provide and/or Staff describe to ACRS.

l e

. g l.

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e _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ . _ _ _ _ _

e e _ - ___ ______

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' Inclosure No. 1 ITIM 'IRANSCRIPT HELTING SaffARY DESCRIPTION ADDRESSED TC >

PAGE .

PAGE -

,~_

I9. .165" -

10 '

Consider the possibility that the Applicant t

• newer carthquakes do nore to the Staff

. '- structum than the orip,inal design.

Reservations on using Parkfield  ;

carthquake. I

, 10 165 .

11 What kind of errors can arise in Applicant E -

\ . seismic design analysir.. Staff ll . 166 11 What am the errors going frun 1 Applicant E [ /, '

dimensional scismic nodel to finite element analysis.

Staff MM-

, 12. 166 11 . Why do the two new spectra provide Applicant E adequate assurance. Staff 0-13 '

~

• . 166 ~

11 How does -he staff decide what Staff [ p g ' <,. ', ' ~ " ,,

. . constitutes an adequate audit s i -

~ .' on seismic design, b4.

. 169 11 Response of instrumnts and equip- Applicant ment to higher accelerations at '

I 172 '

173 .

higher frequencies. i 332 - l' n . . g

)

I 15 L 196 12 Ib11 scale shakisc of stmetums.

Applicant .

204 -

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