ML20006F573

Annual Rept of Safety Valve & Relief Valve Failures & Challenges.

ML20006F573
Person / Time
Site:	Monticello
Issue date:	12/31/1989
From:	NORTHERN STATES POWER CO.
To:
Shared Package
ML20006F570	List: ML20006F569 ML20006F571 ML20006F573
References
NUDOCS 9002280181
Download: ML20006F573 (1)

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MONTICELLO NUCLEAR GENERATING PLANT ,

SAFETY / RELIEF VALVE FAILURES AND CHALLENGES-ke y 1989' . ,

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+ , i This report is'made in accordance with NUREG-0737,.' Item II.K.3.3.and N L Monticello' Technical Specification 6.7. A.6' and covers the periodLof January .1, . j

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1989.through December. 31 -.1989.  ;

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, Failures 1

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I4/8/89- The' air operator and' top works associated with safety relief valve RE 2 71G was' changed.out due?to excessive

' leakage of the-valve's pilot /second' stages.

4 Challences-10/25/89 During. performance of the Section XI ASME Boiler and Pressure Vessel Code reactor coolant system leakage >

test with'the-plant in' code shutdown,>DivisionLII Low'-

.L Low Set Logic was initiated resulting'in the-lifting-of(safety- relief valves RE 2 71G and RV 2-7111= .

Reactor pressure decreased from 1008 psig to 52 psig, 'N s The safety relief valve reset and reactor pressure N returned to approximately'700 psig over,the next.few

' minutes., Reactor vessel temperature remained constant-at approximately 195 F throughout the' event.

Initiation of:the Low Low Set Logic was-caused by an-m

finstrument' sensing line pressure. spike resulting from

, seating of an excess flow. check valve'. The excess flow check valves were being leak tested as required by Technical' Specifications.

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