ML20151D348

Summary of ACRS Subcommittee on Diablo Canyon Meeting on 880223-24 in Burlingame,Ca Re Review of Diablo Canyon Long Term Seismic Program

ML20151D348
Person / Time
Site:	Diablo Canyon
Issue date:	04/07/1988
From:	Advisory Committee on Reactor Safeguards
To:	Advisory Committee on Reactor Safeguards
References
ACRS-2559, NUDOCS 8804140163
Download: ML20151D348 (11)

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April 7,1988

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SUMMARY

/ MINUTES OF THE ACRS SUBCOMMITTEE ON DIABLO CANYON FEBRUARY 23-24, 1988 SAN FRANCISCO, CALIFORNIA The ACRS Subcomittee on Diablo Canyon met at the Sheraton International in Furlingare, California (near the San Francisco airport) on February 23 and 24, 1988 to review the status of the Diablo Canyon Long Term Seismic Program (LTSP).

Notice of the meeting was published in the Federal Register on February 5, 1988 (Attachr.ent A). The schedule of items covered in the meeting is in Attachment B.

A list of handouts kept with the office copy of the minutes is included in Attachment C.

There were no written or oral staterients received or presented from members of the public at the meeting.

E. G. Igne was cognizant ACRS members for the meeting.

Principal Attendees PME C. P. Siess, Chairman D. Brand D. Moeller, ACRS Member L. Cluff W. Kerr, ACRS Member W. Savage J. Ebersole, ACRS Member Yi-Ben Tsai R. Scavuzzo, ACRS Consultant

5. Shattacharya P. Davis, ACRS Consultant R. Domer B. Page, ACRS Consultant D. Ovadia J. Maxwell, ACRS Consultant B. I ew j

i M. Trifunac, ACRS Consultant G. Sarkisian J. Malkin NRC Staff J. Hoch N. Chokshi D. Hamilton i

G. Bagchi B. Norton H. Rood R. Locke R. Rothman J. Blakley M. Treslen f

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• MINUTES /DIABLO CANYON MEETING 2

FEBRUARY 23-24, 1988 B. Smith Others L. Mualchin, Calif. Div of Mines & Geology W. White, Bechtel K. Coppersmith, Geomatrix l

W. Lettis, Geomatrix Highlights 1.

N. Chokshi, RES, presented an overview on the Diablo Canyon Long Term Seismic Program (LTSP), describing background and a sumary of the licensing conditions. He stated that under the direction of the Comissioners and the ACRS the NRC Staff was urged to have a strong review and independent parallel program.

Technical assis-tence in the various areas of work are listed as follows:

o Geology, tectonics and geophysics - USGS and UNR, o

Seismology and ground motion - USGS and LLNL panel, o

Soil structure interaction and Fragility - BNL panel o

Probabilistic Risk Assessment - BNL Presently about 29 workshops, meetings, field trips ani sudits have been held on the LTSP.

Some members of the subcomittee stated that an important objective of the LTSP is to determine a sound method to detemine the seismic design i

basis and not only to determine the seismic design margins, 2.

L. Cluff, PG&E, presented background information on the Diablo Canyon LTSP which led to the Diablo Canyon Nuclear power plant

MINUTES /DIABLO CANYON MEETING 3

FEBRUA.RY 23-24, 1988 i

license condition. The LT5P is now scheduled to be completed in 4

July 1989 after a delay of one year due to resources being diverted i

for legal hearings.

L. Cluff stated that since our last progress report meeting, presentations of some aspects of the LTSP were made at professional society meetings i.e., Seismological Society of America, Geological Society of America and American Geophysical Union. One of the prime purposes for these meetings was to provide peer review.

l 3.

L. Cluff, PG&E, presented the geology, seismology, and geophysics work plan. He stated that the plan was focused and data driven.

Data was acquired from literature review; geological studies including marine and fluvial terraces, age dating and fault i

trenching; offshore and onshore geophysics including COMAPS high resolution near-shore study done by PG&E, Digicon/PGAE deep coastal survey; additional proprietary Western and Nekton CDP lines; reprocessing of selected lines; California State Lands data collected within a 3-mile limit from Diablo Canyon; and the Central Coast seismic network which is now fully operational.

By analysis and interpretation of the above data, preliminary seismic source characterizations were obtained. The following are preliminary results:

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o The LTSP geology seismology and geophysics activities are emphasizing data interpretation leading to seismic source i

characterizations that integrate multidisciplinary data sets l

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MINUTES /DfABLO CANYON MEETING 4

FEBRUARY 23-24, 1988 and analyses, explicitly treat uncer'ininties, and address alternative source characterization models, t

o The San Miguelito and Edna faults are not capable according to Appendix A criteria.

o Pismo synclinorium has not been subject to active folding for the past 700,000 years or longer and is subject to block uplift. The San Luis/Pismo block is bounded by the dip-slip Los Ones fault along this northwestern edge. The Wilmer Avenue, Oceano, Pecho, and San Luis Bay faults are southwest of the block and are discontinuous and have very low slip rates. The Hosgri fault zone bounds the western edge of the

block, o

The November 4. 1927 Lompoc earthquake was a nearly pure dip-slip event having strike about N23W and had a focal depth of 10 km. The seismic moment of the earthquak.e was 1x1020, corresponding to a momert magnitude of 6.6.

The surface wave magnitude was 7.0 4

B. Tsai, PG&E, described the ground motion studies. The objectives were to 1) update the ground motion assessment for the site and 2) provide ground motion data for engineering analysis. Based on 1) anupdatedstrongmotiondatabase,2)refinedgeology, seismology and geophysics information, 3) available ground motion recordings at the site, and 4) use of both empirical and numerical modeling, methods the following ground motion data were provided for engineering analyses:

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MINUTES /DIABLO CANYOH MEETING S

FEBRUARY 23-24, 1988 o

For fragility analysis; 12 sets of empirical acceleration time histories and 14 sets of simulated acceleration time his-l tories.

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For soil-structure interaction analysis; median site-specific l

spectral shape, 3 sets of candidate acceleration time his-tories to ratch the site-specific spectral shape and spatial l

incoberence functions.

S.

W. White, Bechtel/PG1E, provided a brief overview of the seismic analysis that has been tailored to support PRA.

Input requirements.

are 1) structural response; forces in structural elements, deflections, accelerations and response spectra, 2) equipment response; response spectra and deflections and 3) dispersion of response.

Studies perforned thus far includes the following; o

Developeent of median and 84% floor response spectra of the avriliary building, o

Development of median response spectra of all buildings, j

o Effect of incoherent ground motion, and a

Effect of containment base uplift.

6.

W. Tseng, PG5E presented detailed ir.fomation on 1) SSI response tocoherentgroundmotioninputs(verticallypropagating plane-seismic waves) and 2) SSI response a(justment factors due to spatial incoherence of ground motion. These analyses were applied to the containment structure, auxiliary building and turbine building, Unit 2.

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MINUTES /DIABLO CANYON MEETING 6

FEBRUARY 23-24, 1988 7.

R. Kennedy, RPK, Inc., presented information on Diablo Canyon

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fregility evaluation.

He reviewed Phase !! fragility studies.

Essentially the fragilities are keyed to spectral accelerations in s

the 3 to 8.5 hz rarge which provided a somewhat more accurate and l

l less uncertain results. Witt respect to soil structure

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"I interaction, he stated that its effects are assumed to result only l

l frem statistical incoberence from the ground motion wave. For a 150 foot plan dimenstor,at frequencies of 5, 10 and 25 Hz, the a

reduction factors are 1.0, 0.9 and 0.8 respectively.

Probable dominant contributors from Phase 17 study indicate that the diesel generators plus peripherals and overall distress of the turbine building contributed most to the risk.

Seismic risk is dominated between 1.75G - 2.75g, with a corresponding A between 0.75G by SA g

- 1.45 g.

Below a value of S =1.75G (A =0.759) the seismic risk g

g only comes from seismic loss of offsite power coupled with random

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loss of onsite power. On the average, Phase !!! A HCLPF values are not substantially different from Phase !! fragilities.

In general, both redians and randomness have increased. Currently, the i

fragility estimates all of components are being revised to J

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incorporate the following:

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A more realistic site-specific spectra shape, o

Median centered responses analyses for all buildings to site-specific spectra, and j

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o incorporation ci soil structure interaction effects including spatial variation of ground motion, l

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MINUTES /DIABLO CANYON MEETING 7

FEBRUARY 23-24, 1988 8.

B. Smith, PG&E, described the Diablo Canyon Probabilistic Risk Assessment study. The study involves:

o Utilization of Pickard, Lowe and Garrick (PLG) as a lead PRA consultant o

Performing a plant and site specific PRA that will rely heavily on PG8E knowledge and experience o

Extensive PG&E involvement, management oversight of PLG, performing technical PRA work under PLG direction, and review of PRA models and results o

Extensive training of PG&E personnel in PRA techniques o

Transfer of PRA methodology from PLG to PG&E.

The first PRA iteration is about complete and the final iteration has been started. This year's activities (1988) include analysis of deni-nant contributors, final computer runs and final report writing.

The Diablo Canyon PRA features the following:

o Relay chatter and recovery, o

Enhanced seismic analysis, o

Dynamic human actions analyses, and o

Design and construction errors Key engineering issues for the final phase investigation will include 1)

RCP seal LOCA, 2) charging purrp dependence on CCW, 3) fuel oil transfer

MIMUTES/DIABLO CANYON MEETING 8

FEBRUARY 23-24, 1988 system, 4) relay chatter, 5) AC Power recovery following an earthquake and 6) a revised seismic analysis.

The best estimate result for mean core damage frequency (nonseismic 5

events) is about a total of 7.6x10 / year, while the best estimate results from the initial fragility study of mean core damages frequency (seismic events) is about a total of 1.3x1 ~4/ year. These results may change slights after the final studies are complete.

NOTE:

Additional meeting details can be obtained from a transcript of this meeting available in the NRC Public Document Room, 1717 H St., NW., Washington, D.C. or can be purchased from Heritage Reporting Corporation, 1220 L Street, NW.,

Washington, D.C. 20005, (202) 628-4888.

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]I ATTAQHMENT A F

3475

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Federal R:gistir / Vol. 53, No. 24 / Frida~y, February 5,1988 / Notices Y

11 a.m. -Recent activities in the present, may exchange preliminary Commission on December 11,1987. In Office of Commercial Programs.

views regarding matters to be the Federal Register (52 FR 47064-65) 11:30 a.m-SAAC Subcornmittee considered during the balance of the entitled. "Consideration of Issuance of Reports.

meeting.

Amendment to Facility Operating The Subcommittee will then hear License and Opportunity for Prior 1:15 p.m-SAAC discussion:

Recommendations and position presentations by and hold discussions llearing." The proposed amendment with representatives of the NRC Staff

• would delete the provisions in the j

statements.

its consultants, and other interested Technical Specifications relating to the 3 p.m.-Adjourn, persons regarding this review.

hiain Steam Isolation Valve (MSIV)

Ann Bradley, Further information regarding topics Leakage Control System (LCS), and also Advisory Committee Management yficer.

to be discussed, whether the meeting revise the lesyage criteria for primary i

Nationo/ Aeronautics andSpace has been cancelled or rescheduled, the containment allowable leakage through Administration, Chairman's ruling on requests for the the main steam lines.

February 1,1988.

cpportunity to present oral statements The Board is comprised of the J

[FR Doc. 88-2377 Fded 2+88. 8 45 am) and the time allotted therefor can be

""O C00' 75N obtained by a prepaid telephone call to following Administrative judges:

the cognizant ACRS staff member, hit.

Morton B. Margulies, Chatnnan Atomic Elpido Igne (telephone 202/634-1414)

Safety and Licensing Board Panel.

CLE R GULATORY between 8:15 A.M. and 5:00 P.M. Persons U.S. Nuclear Regulatory Commission, planning to attend this meeting are Washington, D.C. 20555 l

i urged to contact the above r amed James H. Carpenter, Atomic safety and Advisory Committee on Reactor individual one or twe iays before the Ucensing Board Panet U.S. Nuclear Safeguards Subcommittee on Diablo scheduled meeting to be advised of any Canyon; Meeting changes in schedule, etc., which may Regulatory Commission. Washington.

The ACRS Subcommittee on Diablo have occurred.

D.C. 20555 Canyon will hold a meeting on February Date: February 2.1988 Gustave H. Unenberger, Jr., Atomic 23 and 2,4,1988, at the Sheraton Morton W. IJbarkin.

Safety and Licensing Board Panel.

International (5 minutes from the San A ssistant. Ex ecutive Directorfor Project U.S. Nuclear Regulatory Commission.

Francisco airport).1177 Airport g,vi,w E

Boulevard. Burlingam. CA.

[FR Doc. 88-1515 Filed 2-4-88,8.45 am)

Issued at Bethesda. Maryland, this teth s'.sy f

The entire meeting will be open to

,w a coog,

of january 1988.

public attendance.

The agenda for the subject meeting B. Paul Cotter, Jr shall be as follows:

[

e o 50-440-OLA; ASLB' No. 84-Chief Administrofire/udge, A tomic Sofety and Ucensing BoardPanel.

Tuesday. Febrvory 23, w88-&30 a.m-until the conclusion of business The Cleveland Electric illuminating (FR Doc. 8&-2513 Fded 2-4-68. 4 45 em)

M ednesday. February 24.1986-8 30 Co.,et al.; Establishment of Atomic swwo cooe rsem.m o.m. until the conclusion of business.

Safety and Ucensing Board

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The Subcommittee will review the Pursuant to delegatim by the IDocket No. 50-219-OM; ASLBP No. 44-status of the Diablo Canyon Long Term Commission dated December 29,1972.

563-01-M1 Seismic Program.

published in the Federal Register,37 F.R.

Oral statements may be presented by 28710 (1972), and Sections 2.105,2.700, General Public Utilities Nuc8 ear Corp.;

members of the public with the 2.702,2.714. 2.714a,2.717 and 2.721 of the Establishment of Atomic Safety and concurrence of the Subcommittee Commission's Regulations, all as Licensing Board Chairman; written statements will be amended, an Atomic Safety and accepted and made available to the Licensing Board is being established in Pursuant to delegation by the Committee. Recordings will be permitted the following proceeding to rule on Commission dated December 29,1972, only during those portions of the petitions for leave to intervene and/or published in the Federal Register,37 FR meeting when a transcript is being kept, requests for hearing and to preside over 28710 (1972), and Sections 2.105, 2.700.

and questions may be asked only by the proceeding in the event that a 2.702,2.714,2.714a,2.717 and 2.721 of the members of the Subcommittee,its hearing is ordered.

Commission's Regulations, all as consultants, and Staff. Persons desiring amended, an Atomic Safety and to make oral statements should notify The Cleveland Electric illuminating Licensing Board is being established in the ACRS staff member named below as Company, et al.: Perry Nuclear Power the following proceeding to rule on far in advance as is practicable so that Plant, Unit No.1, Facility Operating petitions for leave to Intervene and/or appropriate arrangements can be made.

license No. NPF-58 requests for hearing and to preside over During the initial portion of the meeting, the Subcommittee, along with

.This Board is being established the proceeding in the event that a any of its consultants why may be pursuant to a notice published by the hearing la ordered.

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ATTACHMENT B

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DIABLO CANYON LOFG TERM SEISMIC PROGRAM ADVISCRY COMMITTEE ON REACTOR SAFEGUARDS SUBCOMMITTEE MEETING FEBRUARY 23-24, 1988 SPERATON HOTEL, 1177 AIRPORT BLVD.

BURLINGAME, CALIFORNIA 94010 (415) 342-9200 TENTATIVE AGENDA Tuesday, February 23, 1988 8:30 - 9:15 a.m.

Introductions

ACRS T' D ~ S NRC Staff I40-9 M PG&E M 5 L"O D.fr *;w vF s1 QEJfo t id/.,

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9:15 - 10:00 a.m.

W P - Background - PG&E

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90af CL The 1978 ACRS Letter De. j3 The License Cordition Mr i

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The LTSP Program Plan The LTSP Scoping Study

-10:00 - 10:15 a.m.

BREAK s.n 10:15 - l'1:00 a'.m.

Background - PG&E (Continued)

Current Status of LTSP - PG&E*

11:00 - 12:00 NOONv,+ 7 @

Geology / Seismology / Geophysics Mt bo"/ -

iue y u. 5:05 Earthquake Ground Motions twTwi O ~ "M Soil / Structure Interaction 530-005 Fragilities 4 C+

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10 Probabilistic Risk Assessment 3 S*'p to : :)-

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12:00 N000 - 1:00 p.m.

LUNCH t00 v 2:00 p.n.

Current Status of LTSP - PG&E (Continued) 41, c;

-+ 00 - 2+15 p. n.

BREAK 2:15 4:00 p.m.

Current Status of LTSP - PG&E (Continued)

Wednesday, February 24, 1988 - rut e Cov wg n1 9.,,,

'8:30~- 10:30 a.m.

Current Status of LTSP - PG&E (Continued) 10:30 - 10:45 a.m.

BREAK 10:45 - 12:00 NOON Closing Statements NRC Staff PG&E ACRS b

1:00-[:00p.m.

Field Visit For ACRS Members / Consultants interested in visiting Diablo Canyon Power Plant

~I.ik'"~~ndofeachsectionofreviewbyPG&E,itisexpectedthatNRCwill I At ee briefly discuss its status of review.

ATTACHMENT C s

LIST OF HAND 0UTS DIABLO CANYON, FEBRUARY 23-24, 1988 Subcommittee Meeting 1.

NRC Staff Presentation on Diablo. Canyon Seismic Reevaluation - Bob Rothman, RES 1.a Background Materit.1 - Floyd Cluff, PG&E, Diablo Canyon 2.

Geology / Seismology / Geophysics Work Plan - Floyd Cluff 3.

Diablo Canyon Long Term Seismic Program, Gound Motion Studies Ben Tsai, PG&E 4.

Ground Motion - Analysis has been tailored to support PRA 5.

Part I - SSI Responses to Coherent Ground Motion Inputs - Wen Tseng, PG&E 6.

Diablo Canyon Fragility Evaluation - R. P. Kennedy, February 1988 7.

Diablo Canyon Probabilistic Risk Assessment -_ Bruce Smith