05000312/LER-1982-011, Forwards LER 82-011/03L-0.Detailed Event Analysis Submitted

Forwards LER 82-011/03L-0.Detailed Event Analysis Submitted

ML20053A053
Person / Time
Site:	Rancho Seco
Issue date:	05/06/1982
From:	Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20053A054	List: 05000312/LER-1982-011, Forwards LER 82-011/03L-0.Detailed Event Analysis Submitted 05000312/LER-1982-011-03, /03L-0:on 820415,check Valve CBS-022 on B Tank Supply to B Pump Found Stuck Closed.Caused by Chemical Deposit Buildup.Check Valves Cleaned,Reground & Returned to Svc
References
NUDOCS 8205240496
Download: ML20053A053 (2)

LER-1982-011, Forwards LER 82-011/03L-0.Detailed Event Analysis Submitted

Event date:
Report date:
3121982011R00 - NRC Website

text

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CC2VIC esuun SACRAMENTO MUNICIPAL UTILITY DISTRICT O 6201 s st{eet Bo,1 cramento, califomia 95813; (916) 452-3211 f

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May 6, 1982 R H ENGELKEN, REGIONAL ADMINISTRATOR REGION V 0FFICE OF INSPECTION Af!D ENFORCEMENT 11 S NUCLEAR REGULATORY COMMISSION 1450 MARIA LANE SUITE 210 WALNUT CREEK CA 94596 DOCKET NO.

50-312 LICENSE NO.

DPR-54 PEPORTABLE OCCURRENCE NO.

82-11 In accordance with Rancho Seco Nuclear Generating Station Technical Specifications Section 6.9.4.2.b and Regulatory Guide 1.16 Section C.2.b(2), the Sacramento Municipal Utility District hereby submits a 30-day report of Licensee Event Peport 82-11.

Due to observation of a steat but slop inleakage of water into the "A" spray additive tank, the "B" spray additive tank was valved in on February 5, 1982 and the "A" tank was isolated.

The system remained in this configuration until March 19, 1982, when it was confirmed that the "B" tank was experiencino inleakage at a hinher rate than the "A" tank. The system was therefore re-turned to its normal configuration,. with the "A" tank lined up to supply both spray pumps. The inleakage was determined to be backflow from the BNST.

On April 15, 1982, an inspection of the spring piston check valves on both spray additive tank lines revealed the following:

1.

CBS-021 and CBS-028 check valves in the "A" tank supply to the "A" and "d" spray pumps had deposits of chemicals and rouchened areas on their seats which had allowed backflow from the BWST.

2.

CBS-027 check valve in the "B" tank supply to the "A" spray pump was assembled incorrectly; the piston and spring were inverted, which would allow flow throuch the valve in either direction.

3.

CBS-022 check valve in the "B" tank supply to the "B" spray pump was stuck closed, preventing flow in either direction.

All valves were repaired and the seats were reground.

The valves were Model W8-034B-13MS, manufactuied by Velan. A review of maintenance history indicated that no work had been done on site on these valves.

There fore,

CBS-027 was either shioped from the manufacturer with it's piston and spring inverted, or it was incorrectly assembled at scre point during construction.

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R.H. Engelken f1-May 6, 1982 2

- During the period of-time that the "B" tank was valved.in, from February 5,.

1982 to March 19, 1982, there did not exist a flow path ~through CBS-022 to the "B"l spray pump as required by Technical Specifications-Section 3.3.1.C.l.'-

.Conta nment coolina and iodine removal can be provided by.the Reactor' Build-i

.ing Coolers, two of which contain charcoal-filters. Since-the "A" pump, would have provided normal sodium hydroxide addition and the B" pump.-

would.have'still provided spray, although without'N 0H,.more;than adequate-a cooling'and iodine removal would have been provided, if'needed. Therefore, there was no impact on public or' plant safety..

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To q T

John ~J. Mattimo.

Assistant Genera ianager

' and Chief Engineer cc:

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