ML16342B496

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Summarizes 880225 NRC Audit of Selected Seismic Fragility Calculations Performed as Part of long-term Seismic Program. Fragility Curves for Specific Component,At Given Location, Should Not Be Used Generically
ML16342B496
Person / Time
Site: Diablo Canyon  Pacific Gas & Electric icon.png
Issue date: 10/25/1988
From: Rood H
Office of Nuclear Reactor Regulation
To:
Office of Nuclear Reactor Regulation
References
TAC-55305, TAC-68049, NUDOCS 8811140395
Download: ML16342B496 (14)


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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 October 25, 1988 DOCKET NOS.:

50-275 and 50-323 APPLICANT:

FACILITY:

SUBJECT:

PACIFIC GAS AND ELECTRIC COMPANY (PGSE)

DIABLO CANYON NUCLEAR POWER PLANT, UNITS I AND 2

SUMMARY

OF FEBRUARY 25 1988 AUDIT BY THE NRC STAFF OF SELECTED SEISMIC FRAGILITY CALCULATIONS PERFORMED AS PART OF ITS REVIEW OF THE DIABLO CANYON LONG TERM SEISMIC PROGRAM (LTSP)

(TAC NOS.

55305 AND 68049)

On February 25,

1988, the NRC staff and its consultants met with PGSE and its consultants to review and audit selected fragility-related calculations.

Attendees at the meeting are given in Enclosure 1.

Specifically,,the following calculations were reviewed:

1. Probabilistic response analysis of the auxiliary building.
2. Turbine bui 1 ding non-1 inear analysis.

3.

RHR heat exchanger analysis.

4.

125 V DC battery chargers

5. Intake structure.
6. Refueling water storage tank (RWST).

Items I and 2 were reviewed to better understand the overall analytical approach and to "walk through" the calculation packages in order to identify parts of the calculation to be reviewed in more detail, and to be independently analyzed.

Item 3 was reviewed'o understand the methodology used to determine the fragility of a component by analysis.

Item 4 was reviewed to audit a

component whose fragility was developed based on qualification data.

Items 5

and 6 were reviewed to understand the methodology used for structural fragility calculations.

Prior to the audit, the NRC staff and its consultants had received the fragility calculations for 20 components.

Items 2, 3, and 4 were included in these calculations.

8811140395 S81025

PDC, PDR ADOCK 05000275

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11 October 25, 1988 At the conclusion of the audit, the HRC staff and its consultants provided preliminary comments to PGSE.

These comments are given in Enclosure 2.

In

summary, the staff stated that the audit had been productive in clarifying the methodology used by
PGKE, and would facilitate the on-going staff review of the fragility calculations.

Enclosures:

l.

Attendees 2.

NRC staff comments Harry Rood, Senior Project Manager Project Directorate V

Division of Reactor Projects - III, IV, V and Special Projects cc: w/enclosures See next page

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October 25, 1988 At the conclusion of the audit, the NRC staff and its consultants provided preliminary comments to PGSE.

These comments are given in Enclosure 2.

In

summary, the staff stated that the audit had been productive in clarifying the methodology used by PGSE, and would facilitate the on-going staff review of the frag i 1 ity calculations.

Enclosures:

l.

Attendees 2.

NRC staff comments cc: w/enclosures See next page DISTRIBUTION )

NRC 8 Local PDRs PD5 Reading GKnighton HRood OGC EJordan BGrimes NRC Participants ACRS (10)

Nohnson (Region V) original signed by Harry Rood, Senior Project Hanager Project Directorate V

Division of Reactor Projects - III, IV, V and Special Projects DRSP/PD5 0

PD5 HRood:dr G

s hton 10/Q/88 10/g /88 OFFICIAL RECORD COPY

Mr. J.

D. Shiffer Pacific Gas'and Electric Company Diablo Canyon CC:

Richard F. Locke, Esq.

Pacific Gas 5 Electric Company Post Office Box 7442 San Francisco, California 94120 NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.

Box 369 Avila Beach, California 93424 Janice E. Kerr, Esq.

California Public Utilities Commission 350 McAllister Street San Francisco, California 94102 Ms. Sandra A. Silver 660 Granite Creek Road Santa Cruz, California 95065 Mr.

W. C. Gangloff Westinghouse Electric Corporation P. 0.

Box 355 Pittsburgh, Pennsylvania 15230 Managing Editor San Luis Obispo County Telegram Tribune 1321 Johnson Avenue P. 0.

Box 112 San Luis Obispo, California 93406 Mr. Leland M. Gustafson, Manager Federal Relations Pacific Gas and Electric Company 1726 M Street, N.

W.

Washington, DC 20036-4502 Dian M. Grueneich Marcia Preston Law Office of Dian M. Grueneich 380 Hayes Street, Suite 4

San Francisco, California 94102 Mr. Dick Blakenburg Editor 8 Co-Publisher South County Publishing Company P. 0.

Box 460 Arroyo Grande, California 93420 Bruce Norton, Esq.

c/o Richard F. Locke, Esq.

Pacific Gas and Electric Company Post Office Box 7442 San Francisco, California 94120 Dr.

R.

B. Ferguson Sierra Club - Santa Lucia Chapter Rocky Canyon Star Route Creston, California 93432 Chairman San Luis Obispo County Board of Supervisors Room 270 County Government Center San Luis Obispo, California 93408 Director Energy Facilities Siting Division Energy Resources Conservation and Development Commission 1516 9th Street Sacramento, California 95814 Ms. Jacquelyn Wheeler 3033 Barranca Court San Lu i s Obi spo, Ca 1 iforni a 93401

Pacific Gas II Electric Company Diablo Canyon CC:

Ms. Laurie McDermott, Coordinator Consumers Organized for Defense of Environmental Safety 731 Pacific Street, Suite 42 San Luis Obispo, California 93401 Mr. Jack McGurk, Acting Chief Radiological Health Branch State Department of Health Services 714 P Street, Office Building II8 Sacramento, California 95814 Regional Administrator, Region V

U.S. Nuclear Regulatory Commission 1450 Maria Lane Suite 210 Wa'Inut Creek, Cal ifornia 94596 Ms. Nancy Culver 192 Luneta Street San Lu i s Ob i spo, Ca 1 iforni a 93401 President California Public Utilities Commission California State Building 350 McAllister Street San Francisco, California 94102 Michael M. Strumwasser, Esq.

Special Assistant Attorney General State of California Department of Justice 3580 Wi lshire Boulevard, Room 800 Los Angeles, California 90010

ENCLOSURE I ATTENDEES 02/25/88 Fragility Audit, Diablo Canyon Long Term Seismic Program NAME P. Antiochos H. Ashar G. Bagchi S. Battachanra M. Bohn N. Chokshi L. S. Cluff R.

Domer J.

Johnson R.

P.

Kennedy T. Kipp D. Ovadia J.

Portney J.

Reed H.

Rood B. Sarkar D. Mesley ORGANIZATION PGEE NRC/NRR/ESGB NRC/NRR/ESGB PGSE Sandia (NRC)

NRC/RES/PRAB PGSE PG8IE EqE (NRC)

Structural Mechanics Consulting (PGSE)

NTS (PGKE)

PG&E PG5E JBA (PGSE)

NRC/NRR/PDV Bechtel (PG5E)

Impell (PGSE)-

Enclosure 2

Comments The following preliminary comments were made by the NRC staff and consultants at the conclusion of the audit.

tagore detailed comments will be provided at a

later date.

It needs to be assured that the fragility curves for a specific component at a given location are not used generically, that is, they are not substituted for similar components at other locations in the PRA quantification.

2.

Review of the RHR Heat Exchanger indicated that fragility calculation, particularly the identification of governing failure mode (anchor bolts),

was based on a two page equipment seismic qualification summary.

However, it was difficult to reconcile this failure mode with the actual support configuration of the exchanger.

Therefore, it is suggested that some further investigations be conducted to fully understand the seismic behavior of this component.

For other components whose fragility calculations are based on such equipment qualification summaries, it should be assured that the information contained in summaries is appropriate for fragility development.

3.

It was noted that the different values for uncertainty parameters are used for north-south and east-west components of ground motion in the fragility calculations.

The use of different uncertainty values needs to be justified.

4.

The effects of high frequency motion which wi 11 be generated as a

result of an impact between the turbine pedestal and the Turbine Building needs to be addressed in the fragility development.

5.

It appears that the Turbine Building analysis has been performed for a few high acceleration level ground motions.

Using these results to scale spectral accelerations for other lower level ground motions may lead to their underestimation.

If such a scaling was used then this point needs further clarification.

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