ML20006F573
| ML20006F573 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 12/31/1989 |
| From: | NORTHERN STATES POWER CO. |
| To: | |
| Shared Package | |
| ML20006F570 | List: |
| References | |
| NUDOCS 9002280181 | |
| Download: ML20006F573 (1) | |
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i MONTICELLO NUCLEAR GENERATING PLANT g
SAFETY / RELIEF VALVE FAILURES AND CHALLENGES-
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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,.
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.;e 1989.through December. 31 -.1989.
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, Failures 1
I4/8/89-The' air operator and' top works associated with safety
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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,
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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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