ML20090D839

AO-50-219/74-61:on 741218,stack Gas Sample Line Flow Alarm Received Following Automatic Operation of Auto Transfer Switch IT-4.Caused by Opening of 230 Kv Circuit Breakers in & N7.Pump Restarted

ML20090D839
Person / Time
Site:	Oyster Creek
Issue date:	12/26/1974
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
AO-50-219-74-61, NUDOCS 8303030219
Download: ML20090D839 (3)

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Jersey Central Power & Light Company q yy)i MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J. 07960

• 201-539-6111 ne wes e w r.

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General I /E**

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December 26, 1974 9'  ??(f-(k.h"T1'CA '

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, as y Mr. A. Giambusso '-

Deputy Director for Reactor Projects Directorate of Licensing United States Atomic Energy Commission Washington, D. C. 20545

Subject:

Oyster Creek Station Docket No. 50-219 Abnormal Occurrence Report No. 50-219/74-61 i

The purpose of this letter is to forward to you the attached

- Abnormal Occurrence Report in compliance with paragraph 6.6.2.a of the Technical Specifications.

Enclosed are forty copies of this submittal.

i Very truly yours, j ~(f)U vY VWM Donald A. Ross Manager, Generating Stations-Nuclear es Enclosures cc: Mr. J. P. O'Reilly, Director Directorate of Regulatory Operations, Region 1

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M pm 8303030219 741226 -

PDR ADOCK 05000219 S PDR COPY SENT REGION -

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} MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J.07960

• 201-539-6111

...a , a ra General .}. { Public Utihties Corposation SFSTim OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence Report No. 50-219/74-61 Report Date December 26, 1974 Occurrence Date December 18, 1974

Identification of Occurrence Violation of the Technical Specifications, paragraph 3.6. A.3, failure of the stack gas sample system to continuously monitor stack releases while the reactor was in an unisolated condition. This event is considered to be an.

abnormal occurrence as defined in the Technical Specifications, parstgraph 1.15B.

Conditions Prior to Occurrence The plant was at steady state power with major parameters as follows:

Power: Core, 1904 MWt Electric, 670 MWe 4

Flow: Recirculation, 18.7 x 10 gpm Feedwater, 7.20 x 10 lb/hr 6 Reactor Pressure: 1020 psig Stack Gas: 25,800 pCi/sec Description of Occurrence At approximately 2200 on December 18, 1974, a stack gas sample line low flow alarm was received following the automatic operation of auto transfer switch IT-4. The auto transfer switch transferred from its primary source of power, VMCC IB2, to its backup source, 'alCC 1A2. The momentary power loss caused the stack gas sample pump to trip. An operator was immediately dispatched to check the stack gas sample pump. The stack gas sample pump was restarted locally by the operator at 2201. The total amount of time the stack gas sample pump was out of service was approximately one minute.

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Abnormal Occurrence Report No. 50-219/74-61 Page 2 Apparent Cause of Occurrence The opening of 230 KV circuit breakers IN and N7, initiated by a fault on 230 KV transmission line N-1028, caused a momentary voltage disturbance on the plant electrical distribution system. This disturbance, reflected on instrument panel No. 4, initiated the automatic transfer switch IT-4. The momentary loss of voltage to the stack gas sample pump caused the pump trip by opening contacts in its start-stop switch seal in circuit.

Analysis of Occurrence A review of the stack gas radiation monitor recorder traces showed the levels of both monitor channels to be relatively constant (at 600 cps) before and after the pump trip. In a further effort to determine if excessive stack releases might have occurred during the approximate period that the stack gas sample pump was not operating, recorder traces of radiation monitoring systems associated with two gaseous streams released through the stack was reviewed. A review of the off gas radiation monitor recorder traces showed that the levels of both monitor channels were relatively constant (at approxi-mately 1.5 x 103 mr/hr) with no spiking for a period of approximately 60 minutes prior to this event. Sixty minutes is the off gas system holdup time prior to releasing to the stack. In addition, a review of the reactor building ventilation exhaust radiation monitor recorder traces showed that at the time of this event, the levels of both monitor channels were relatively constant (at approximately 1.8 mr/hr) with no spiking. Based on these considerations and the very short period of time that the stack gas sample pump was not operating, the safety significance of this event is considered to be minimal.

Corrective Action The stack gas sample pump was restarted by depressing the start switch locally at the pump. The seal in circuit that caused the failure has been temporarily bypassed to eliminate its function until a permanent change can be made.

Failure Data i

l Previous abnormal occurrences involving the stack gas sample pump:

1. Abnormal Occurrence Report No. 50-219/74-53 l

! 2. Abnormal Occurrence Report No. 50-219/74-54

3. Abnormal Occurrence Report No. 50-219/74-57 l

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