05000312/LER-1981-055, Forwards LER 81-055/03L-0.Detailed Event Analysis Submitted

Forwards LER 81-055/03L-0.Detailed Event Analysis Submitted

ML20039C358
Person / Time
Site:	Rancho Seco
Issue date:	12/11/1981
From:	Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20039C359	List: 05000312/LER-1981-055, Forwards LER 81-055/03L-0.Detailed Event Analysis Submitted 05000312/LER-1981-055-03, /03L-0:on 811118,reactor Protection Sys Pressure Transmitters in B & C Channels Found to Have Drifted.Cause Not Stated.Setback of 20 Psi Implemented & Transmitters Rezeroed
References
NUDOCS 8112290272
Download: ML20039C358 (2)

LER-1981-055, Forwards LER 81-055/03L-0.Detailed Event Analysis Submitted

Event date:
Report date:
3121981055R00 - NRC Website

text

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i SACRAMENTO MUNICIPAL UTILITY DISTRICT t] 6201 S Street, Box 15830[CJ 'i, pto, California Sacrame 95813; (916) 452-3211 i

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D R H ENGLEKEN, DIRECT 0P REGOVED REGION V 0FFICE OF INSPECTION & ENFORCEMENT U S NUCLEAF REGULATORY COMMISS10N t

DEC2 81981 > Rt 1450 MARIA LANE SUITE 210 88 d"" 3 E 7,-

WALUUT CREEK CA 94596 n;c ~~

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M' DOCKET NO. 50-312 LICENSE NO. DPR-54 j.

REPORYABLE OCCURRENCE NO. 81-55

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in accordance with Pancho Seco Nuclear Generating Station Technical Spe ifications Section 6.9.L.2.a and Regulatory Guide 1.16, Section

. C.2.b(1), the Sacrarrento Municipal Utili ty District is submitting a thirty-day report of Reportable 0ccurrence 81-55 On November 18, 1981 while performing Instrucent Surveillance ~I-11L, it was noted that the Reactor Protection System pressure transmitter dri f t for Channel B exceeded -10 psi and Channel C exceeded +10 psi.

,,Therd was a 10 psi conservative setback in the trip setpoints so that tbctiigh pressure trip setpoint was at 2290 psig and the low pressure s

. tr i p se t po i n t wa s a t 1910 psig. This was intended to ensure that the Technical Speci fication retpoints of 2300 psic and 1900 psig, respec-tively,,would_not be exceeded. Vith the dri f t creater than 10 psi in these two channels, it became possible for those setpoint-to be

. exceeded..in'the af fected channels wi thout causing a channel trip.

The ti}idsmitters are Westinghouse Electric model 59 Pn/PH transmitters.

When this.<.ondition was noted, a 20 psi setback was immediately put ir place on Cha.:nels B and C to restore the conservatism. The Plant Review Committee met to consider corrective actions and determined that the 20 psi conservatism should be applied to all P.PS pressure transmitters.

On November 23, 1981, the main generat( r was taken off line for turbine 4

re-balancing and the reactor w4s sh M.un.

During that outage, the transmitters were re-zerced. The Plant Review Committee again considered

,the situation and determined that a 10 psi conservative setback could be allowed, provided a drift check would be perfor tred every two ween to ensure that consdrvatism is maint.ained.

.s 09,k 8112290272 811211 PDR ADOCK 05000312 S

PDR 7N ELECTPlc tYSitM SERVtNG 4GRE THAN 600.000 IN THE HEART aF C Alt f o R N I A

e R. H. EnG'.lken December 11, 1981 No transients resulted f rom this event nor was public or plant safety effected since sufficient instrumentation was available to ensure plant shutdown on hich or low pressure, h.

M d

ohn. Mattimoe Assistant General Manager and Chief Engineer cc:

l&E Washington (30)

MIPC (3)

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