ML13331B002

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Forwards Request for Addl Info Re Plant Salt Water Cooling Sys Reliability Study
ML13331B002
Person / Time
Site: San Onofre Southern California Edison icon.png
Issue date: 11/24/1987
From: Bradfute J
Office of Nuclear Reactor Regulation
To: Baskin K
Southern California Edison Co
References
TAC-65149 NUDOCS 8712020461
Download: ML13331B002 (3)


Text

November 24, 1987 Docket No. 50-206 Mr. Kenneth P. Baskin Vice President Southern California Edison Company 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770

Dear Mr. Baskin:

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION ON SAN ONOFRE 1 SALT WATER COOLING SYSTEM RELIABILITY STUDY (TAC NO. 65149)

To complete our review of the subject SEP item, we find that we need your response to the enclosed questions and comments. If you have questions regarding this request please contact me.

Sincerely, original signed by John 0. Bradfute, Project Manager Project Directorate V Division of Reactor Projects -III, IV, V and Special Projects

Enclosure:

As stated DISTRIBUTION:

Docket File NRC & L PDRs PD#5 Plant JLee GKnighton JBradfute OGC-BETH EJordan JPartlow ACRS (10)

Ph55 JLe cw JBradfute 1

7 11/2487 11//87 8712020461 871124 PDR ADOCK 05000206 P

PDR

Mr. Kenneth P. Baskin San Onofre Nuclear Generating Southern California Edison Company Station, Unit No. 1 cc Charles R. Kocher, Assistant Mr. Joseph 0. Ward, Chief General Counsel Radiological Health Branch James Beoletto, Esquire State Department of Health Southern California Edison Company Services Post Office Box 800 714 P Street, Office Bldg. 8 Rosemead, California 91770 Sacramento, California 95814 David R. Pigott Mr. Hans Kaspar, Executive Director Orrick, Herrington & Sutcliffe Marine Review Committee, Inc.

600 Montgomery Street 531 Encinitas Boulevard, Suite 105 San Francisco, California 94111 Encinitas, California 92024 Mr. Stephen B. Allman Dennis M. Smith, Chief San Diego Gas & Electric Company Radiological Programs Division P. 0. Box 1831 Governor's Office of Emergency Svcs.

San Diego, California 92112 State of California 2800 Meadowview Road Sacramento, CA 95832 Resident Inspector/San Onofre NPS c/o U.S. NRC P. 0. Box 4329 San Clemente, California 92672 Mayor City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors County of San Diego San Diego, California 92101 Director Energy Facilities Siting Division Energy Resources Conservation &

Development Commission 1516 -

9th Street Sacramento, California 95814 Regional Administrator, Region V U.S. Nuclear Regulatory Commission 1450 Maria Lane Walnut Creek, California 94596

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QUESTIONS AND COMMENTS REGARDING SAN ONOFRE 1 SALT WATER COOLING SYSTEM RELIABILITY STUDY (1) The SWCS reliability study does not address specifically the responses of the SWCS to various initiating events (for example, the loss of offsite power event). Show that the estimated SWCS unreliability is bounding for all the initiating events that would affect the SWCS unreliability.

(2) The common-cause failures are not treated explicitly in the fault tree for the SWCS unreliability. Show that the estimated SWCS unreliability includes the contribution of common-cause failures that may affect the operation of pumps, valves and other components in the SWCS.

(3) The SWCS unreliability may be affected by testing. For example, an operator may leave a manual valve in the closed position after a test.

Show that the testing contribution to the SWCS unreliability is not significant.

(4) It is not obvious whether the SWCS fault tree includes failures of pump breakers and their instrumentation and controls. Determine their contribution to the SWCS unreliability.

(5) The SWCS at SOMGS-1 has experienced many failure events relating to its pumps and valves. Hence, provide a technical basis that the generic failure rates in the Interim Reliability Evaluation Program (IREP) data base are appropriate for use in the SWCS reliability study for SONGS-1.