ML19354C437

AO 50-219/74/36:on 740710,RE03D Reactor High Pressure Sensor Failed to Trip at Point Less than or Equal to 1,060 Psig. Caused by Lack of Allowance for Setpoint Tolerances in Tech Specs.Sensor Recalibr & Returned to Svc

ML19354C437
Person / Time
Site:	Oyster Creek
Issue date:	07/18/1974
From:	JERSEY CENTRAL POWER & LIGHT CO.
To:
References
AO-50-219-74-36, NUDOCS 8103040496
Download: ML19354C437 (2)

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Jersey Central Power & Light Company MADISON AVENUE AT PUNCH BOWL ROAD

• WORRISTOWN, N.J.07960

• 201-530-4111 um. = r-Genefal Public Utmt.es Corporaton OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 05731 Abnormal Occurrence Report No. 50-219/74/36 Report Date July 18, 1974 Occurrence Date July 10, 1974 Identification of Occurrence Violation of the Technical Specifications, paragraph 2.3.3, failure of the RE03D reactor high pressure sensor to trip at a point corresponding to a reactor pressure of <1060 psig. This event is considered to be an abnormal occurrence as defined in the Technical Specifications, parcgraph 1.15A.

Conditions Prior to Occurrence At the time of the event, the plant was at steady state power with the major parameters as follows:

Power: Core, 1913 MWt Electric, 635 MWe Flow: Recirculation,15.9 x 10 gpm Feedwater, 7.22 x 10 6 lb/hr Stack Gas: 12,430 pCi/sec Description of Occurrence While performing a routine monthly surveillance test on the reactor high pressure sensors, RE03A, B, C, and D, it was observed that RE03D tripped at 1070 psig.

This is .* psig above its normal trip point of 1066 psig which reflects a sensor head correction of 6 psig. The surveillance test results were as follows:

- M_22Allbell R -

I

'Y Abnormal Occurrence No. 50-219/74/36 Page 2 As Found As Left Normal Trip Point Trip Point Trip Point RE03A 1068 psig 1068 psig 1068 psig RE03B 1068 psig 1068 psig 1068 psig RE03C 1064 psig 1064 psig 1066 psig RE03D 1070 psig 1066 psig 1066 psig Apparent Cause of Occurrence The cause of this occurrence is the lack of allowance for set point tolerances in the Technical Specifications.

Analysis of Occurrence The safety significance of this event lies in a loss of system redundancy. Had a pressure excursion occurred, the redundant sensor, RE03C, would have functioned j properly and would have terminated the pressure transient in conjunction with the proper actuation of the RE03A and B sensors.

i Corrective Action .

The sensor was recalibrated and returned to service. Set point accuracy and tolerance in not only these instruments but in others as well are under investi-gation by Jersey Central Power & Light Company, GPU' dcrvice Corporation, and General Electric Company personnel. This investigation was delineated in Abnormal Occurrence No. 50-219/74/35, dated (report) July 15, 1974, in the Corrective Action discussion.

Failure Data Manufacturer: Barksdale Type: Pressure Actuated Switch Switch No.: B2T-A12SS

Reference:

Abnormal Occurrence Report No. 50-219/74/7

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