ML16343A545
| ML16343A545 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 12/04/1997 |
| From: | Steven Bloom NRC (Affiliation Not Assigned) |
| To: | Rueger G PACIFIC GAS & ELECTRIC CO. |
| Shared Package | |
| ML16342D905 | List: |
| References | |
| REF-GTECI-*****, REF-GTECI-057, REF-GTECI-103, REF-GTECI-131, REF-GTECI-147, REF-GTECI-148, REF-GTECI-156, REF-GTECI-A-45, REF-GTECI-DC, REF-GTECI-NI, TASK-***, TASK-057, TASK-103, TASK-131, TASK-147, TASK-148, TASK-156, TASK-57, TASK-A-45, TASK-OR GL-88-20, TAC-M83614, TAC-M83615, NUDOCS 9712160403 | |
| Download: ML16343A545 (6) | |
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U!iI!TEDSTATES NUCLEAR REGULATORY COMMISSION WA8HINGTON> D.C. 205S&0001 December 4,
1997 Mr. Gregory M. Rueger, Senior Vice President and General Manager Pacific Gas and Electric Company Nuclear. Power Generation N9B P. 0.
Box 770000 San Francisco.
Cali fornia 94177
SUBJECT:
REVIEW OF DIABLO CANYON INDIVIDUALPLANT EXAMINATION OF EXTERNAL EVENTS (IPEEE)
SUBMITTAL (TAC NOS.
M83614 AND M83615)
Dear Mr. Rueger:
By letter dated June 27.
- 1994, as supplemented by letter dated November 13.
1995, Pacific Gas and Electric Company submitted its response to the June 28, 1994, Generic Letter (GL) 88-20, Supplement 4 (with NUREG-1407, Procedural and Submittal Guidance) for the Diablo Canyon Power Plant (DCPP).
Supplement 4
requested all licensees to perform individual plant examinations of external events (IPEEE) to identify plant-specific vulnerabilities to severe accidents and to report the results to the Commission together with any licensee-determined improvements and corrective actions.
Enclosed is the staff's Evaluation Report (ER). with the contractor's Technical Evaluation Report (TER) of the review that was performed.
A Step 1 review was performed which examined the IPEEE results for their "reasonableness" considering the design and operation of the plant.
On the basis of the review performed by the contractor and reviewed by a senior review board, the NRC concluded that the aspects of seismic, tires, and high winds, floods.
and transportation and others were adequately addressed.
The staff's and contractor's review findings are summarized in the enclosed ER, and the details of the contractor 's findings appear in the attachment to the ER.
The licensee estimated a seismic core damage frequency (CDF) of 4.2E-5 per reactor-year (RY) using a site-specific hazard curve.
and a fire CDF of 2.7E-5/RY.
The licensee also estimated that the contributions from other external events (e.g.. external floods and high winds) are insignificant at the Diablo Canyon site.
The licensee estimated that the CDF due to internal events is about 8.8E-5/RY. including internal flooding.
The licensee defined a potential severe accident vulnerability as having any component, system.
operator action, or accident sequence that contributes more than 50 percent to the CDF or has CDF greater than 1E-4/RY [criteria recommended by Nuclear Management and Resources Council (NUMARC)]g The licensee did not identify any potential vulnerabilities associated with external
- events, thus.
no improvements related to external events were considered as necessary.
- However, a number of plant-specific improvements Pr" i.'
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Mr. Gregory M. Rueger December 4,
1997 were implemented as a part of the Long Term Seismic Program (LTSP) at OCPP.
These improvements wi 1) improve the seismic safety and reduce potential seismic vulnerabi lities at DCPP.
The licensee has addressed generic safety issues (GSIs) GSI-131, "Potential Seismic Interaction Involving the Movable In-Core Flux Mapping System in Westinghouse Plants,"
GSI-103, "Design for Probable Maximum Precipitation (PMP)," and USI A-45, "Shutdown Decay Heat Removal Requirements" which were explicitly requested in Supplement 4 to GL 88-20.
On the basis of the Step 1 review, the staff concludes that the licensee's IPEEE process is capable of identifying the most likely severe accidents and severe accident vulnerabi lities and, therefore, that the Diablo Canyon IPEEE has met the intent of Supplement 4 to GL 88-20.
In addition, the licensee's IPEEE submittal contains some specific information that addresses the external event aspects of certain generic safety issues
[e.g.,
GSI 147, "Fire-Induced Alternate Shutdown/Control Room Panel Interactions."
GSI 148,. "Smoke Control and Manual Fire-Fighting Effectiveness,"
and GSI 172, "Multiple System Responses Program (MSRP)".3 The specific information associated with each issue is identified and discussed in the TER.
Based on the staff's and contractors'eviews of the information contained in the submittal, the staff considers that the licensee's process is capable of identifying potential vulner abilities associated with these issues.
On the basis that no vulnerabi lities associated with the external event aspects of these issues were identified at DCPP, the staff considers these issues resolved.
If you have any questions regarding the attached ER, please contact me at (301) 415-1313.
Sincerely.
Original Signed By Steven D. Bloom, Project Manager Project Directorate IV-2 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket Nos.
50-275 and 50-323
Enclosure:
Evaluation Report cc w/encl:
See next page Document Name:
OC83615.SE DISTRIBUTION:
Docket PUBLIC PDIV-2 Reading EAdensam (EGA1)
WBateman SBloom MCunningham, RES EPeyton OGC ACRS RHernan
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Mr. Gregory M. Rueger December 4,
1997 cc w/encl:
NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.
Box 369 Avila Beach, Cali for nia 93424 Dr. Richard Ferguson, Energy Chair Sierra Club California 1100 11th Street, Suite 311 Sacramento.
Cali fornia 95814 Ms.
Nancy Culver San Luis Obispo Mothers for Peace P.
O.
Box 164 Pismo Beach, California 93448 Chairman San Luis Obispo County Board of Supervisors Room 370 County Government Center San Luis Obispo, California 93408 Mr. Truman Burns Mr. Robert Kinosian California Public Utilities Commission 505 Van Ness, Room 4102 San Francisco, Cali fornia 94102 Mr. Steve Hsu Radiologic Health Branch State Department of Health Services Post Office Box 942732 Sacramento, California 94232 Diablo Canyon Independent Safety Committee ATTN:
Robert R. Wellington, Esq.
Legal Counsel 857 Cass Street, Suite D
Monterey, California 93940 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Harris Tower 8 Pavi llion 611 Ryan Plaza Drive. Suite 400 Arlington, Texas 76011-8064 Christopher J.
- Warner, Esq.
Pacific Gas 8 Electric Company Post Office Box 7442 San Francisco.
California 94120 Mr. Robert P.
Powers Vice President and Plant Manager Diablo Canyon Nuclear Power Plant P. 0.
Box 56 Avila Beach. California 93424 Telegram-Tribune ATTN:
Managing Editor 1321 Johnson Avenue P.O.
Box 112 San Luis Obispo, California 93406
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