ML13331A036

Summary of 801030 Meeting W/Util in Bethesda,Md Re Loss of Saltwater Cooling Event at Facility & Effects of Desiccant in Compressed Air Sys.W/List of Attendees

ML13331A036
Person / Time
Site:	San Onofre
Issue date:	01/06/1981
From:	Nowicki S Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
TAC-65149, NUDOCS 8103020712
Download: ML13331A036 (7)

Text

oG UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 January 6, 1981 Docket No. 50-206 LICENSEE:

SOUTHERN CALIFORNIA EDISON COMPANY FACILITY:

SAN ONOFRE NUCLEAR GENERATING STATION NO. 1

SUMMARY

OF OCTOBER 30, 1980 MEETING TO DISCUSS THE LOSS OF SALT WATER COOLING EVENT AT SAN ONOFRE UNIT 1 AND THE EFFECTS OF DESICCANT IN THE COMPRESSED AIR SYSTEM NRC and Southern California Edison Company (SCECo) representatives met in Bethesda, Maryland, on October 30, 1980, to discuss the March 10, 1980 loss of salt water cooling at San Onofre Nuclear Generating Station Unit 1 (SONGS I) and a related concern of desiccant contamination of the compressed air system.

The meeting attendees are listed in Enclosure 1.

SCE was asked to provide additional information related to the March '10, 1980 failure of the Salt Water Cooling System (SWCS), time and temperature limits of equipment serviced by the SWCS, and details of desiccant con tamination. A discussion of the major items reviewed at the meeting is provided below.

Desiccant Contamination:

Possible desiccant migration in the compressed air system was first observed in October, 1978 when a gritty substance appeared to cause sluggish operation of the non-safety related feedwater regulator valves.

In December 1979, desiccant was suspected as the possible cause of failure of a service water isolation valve.

Finally, on March 10, 1980, failure of a discharge valve in the salt water cooling system was attributed to excessive 0-ring wear possibly caused by desiccant in the air system.

SCE corrective action includes blowing down the air lines, changing the desiccant, weekly inspection of the air filter, and addition of a seal or filter material in theannulus around the existing filter.

The safety objective of this corrective action being to prevent grit from entering systems to preclude common mode failures. All of the safety related valves will be inspected prior to start up. Some undisclosed number of the safety related valves were already disassembled and cleaned and 9 valves were noted to have grit in the mechanism. The staff asked if a station safety review resulting in approved procedures had been performed prior to the valve inspection and cleaning. SCE representatives at the meeting were not certain but they would check if approved procedures were used.

8 108020 71

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January 6, 1981 SCE said that they would review the desiccant contamination and consider whether the effect of the desiccant on the valves constituted an unre viewed safety question.

SCE indicated at the meeting that they had not reached a decision on a formal report but that they were documenting corrective actions taken. In any case the documented information would be available for NRC review. AEOD suggested that a report appeared appropriate.

Loss of Salt Water Cooling:

The March 10, 1980 loss of salt water cooling event was described by SCE.

One SWCS pump shaft failed, the other SWCS pump isolation discharge valve failed to open (0-ring wear possibly due to desiccant contamination), and the auxiliary SWCS pump failed to prime. This series of events resulted in a complete loss of salt water cooling for approximately 15 minutes until salt water flow from the screen wash pumps was cross connected to the discharge piping of the north salt water cooling pump.

About three hours after the south SWCS pump shaft failed,the north pump isolation discharge valve was opened manually to restore SWCS flow. The plant operated at or near full power during the event and some plant equipment normally cooled by the component cooling water system operated at slightly elevated temperatures.

SWCS pump shaft failures had been experienced previously at SONGS I. In 1975 the north pump shaft failed.

In 1978 the south pump shaft was repaired and in 1980 the south pump shaft failed again.

SCE believes the mode of failure to be fatigue due to excessive shaft vibration although metallographic examinations were not conducted.

SCE stated that their new preventative maintenance program will be adequate to preclude recurrance of the March 10 type failure.

SCE analyzed the facility response following a loss of coolant accident (LOCA) or a main steam line break (MSLB), and a loss of offsite power when determining the effects of losing all salt water cooling. Final equipment temperatures resulting from loss of SWCS and the limiting temperatures for the plant equipment were not known. SCE agreed to send data on the limiting temperatures for the reactor coolant pump and a description of the location of the RTDs.

SUMMARY

SCE stated that:

(1) their corrective actions to preclude a recurring loss of salt water cooling and desiccant contamination in the air system are adequate, (2) they will consider preparing a report concerning the desiccant contamination, and (3) they are reviewing their existing preventative main tenance program and will prepare a detailed preventative maintenance program.

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January 6, 1981 The NRC will review the data presented at'the meeting, and additional data SCE agreed to provide, during preparation of the NRC report and recommendations.

Stanley J. Nowicki, Project Manager Operating Reactors Branch #5 Division of Licensing

Enclosure:

List of Attendees cc w/enclosure:

See next page

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January 6, 1981 cc Charles R. Kocher, Assistant Director, Criteria and Standards General Counsel Division Southern California Edison Company Office of Radiation Programs Post Office Box 800 (ANR-460)

Rosemead, California 91770 U. S. Environmental Protection Agency David R. Pigott Washington, D. C. 20460 Samuel B. Casey Chickering & Gregory U. S. Environmental Protection Three Embarcadero Center Agency Twenty-Third Floor Region IX Office San Francisco, California 94111 ATTN:

EIS COORDINATOR 215 Freemont Street Jack E. Thomas San Francisco, California 94111 Harry B. Stoehr San Diego Gas & Electric Company P. 0. Box 1831 San Diego, California 92112 Resident Inspector c/o U. S. NRC P. 0. Box AA Oceanside, California 92054 Mission Viejo Branch Library 24851 Chrisanta Drive Mission Viejo, California 92676 Mayor City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors County of San Diego San Diego, California 92101 California Department of Health ATTN:

Chief, Environmental Radiation Control Unit Radiological Health Section 714 P Street, Room 498 Sacramento, California 95814

En ure 1 LIST OF ATTENDEES NAME COMPANY R. W. Krieger SCE George J. Stawniczy SCE Leo Derderian NRC/DSI/SIB Jack Crooks NRC/MPA/LOEB Jim Stone NRC/IE /FC Mat Taylor NRC/SRR J. S. Creswell AEOD J. R. Tate SCE S. J. Nowicki NRC R. Riggs NRC R. Hermann NRC/IE-HQ H. L. Ornstein NRC/AEOD

DISTRIBUTION e

~cket NRC PDR Local PDR ORB Reading H. R. Denton E. G. Case D. Eisenhut R. Purple J. Roe T. Novak R. Tedesco G. Lainas G. Zech J. Heltemes, AEOD S. Varga T. Ippolito R. Clark R. Reid S. Nowicki OELD OI&E (3)

HSmith ACRS (16)

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0-329.82

,-RC FORM 318 (10/80) NRCM O240 OFFICIAL REppCORD COPY USGPO: 1980-329-824

DISTRIBUTION Docket NRC PDR Local PDR ORB Reading H. R. Denton E. G. Case D. Eisenhut R. Purple J. Roe T. Novak R. Tedesco G. Lainas G. Zech J. Heltemes, AEO0 S. Varga T.. Ippolito R. Clark R. Reid S. Nowicki OELD OI&E (3)

HSmith ACRS (16)

NRC participant NSIC TERA cc list