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.ersey Central Power & Light Company MADISON AVENUE AT PUNCH BOV1 ROAD e MORRISTOWN, N.J.07960
- 201-539-6111 eamans av m General Public Utilities Corporation May 23, 1974
.Mr. A. Giambusso Deputy Director for Reactor Projects Directorate of Licensing United States Atomic Energy Commission Washington, D. C. 20545
Dear Mr. Giambusso:
Subject:
Oyster Creek Station Docket No. 50-219 Abnormal Occurrence Report No. 50-219/74/30 The purpose of this letter is to forward to you the attached Abnormal Occurrence Report in compliance with paragraph 1.15B of the Technical Specifications.
Enclosed are forty copies of this submittal.
Very truly yours,
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Donald A. Ross Manager, Nuc~ ear Generating Stations Pk Enclosures cc: M J. P. O'Reilly, Director Directorate of Regulatory Operations, Region 1 1
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i OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence Report No. 50-219/74/30 a
Report Date May 23, 1974 Occurrence Date May 14, 1974-t Identification of Occurrence Violation of the Technical Specifications, Table 3.1.1. A.12,. which requires Tthe generator load rejection scram to be operable at turbine steaming rates greater than 40% of rated while in the RUN mode.
This event is considered to be an abnormal occurrence as defined in the Technical Specifications, paragraph 1.15B.
Conditions Prior to Occurrence The plant was shut down for refueling.
Description of Occurrence While performing routine surveillance testing on the generator load rejection anticipatory scram, it was observed that pressure switch PSH-C failed to trip-at the nominal trip pressure of 180 psig.
The switch senses third stage extraction pressure from the H.P. turbine and forms a bypass around the PSL-C pressure switch contacts, which senses acceleration relay oil pressure, and the turbine stop valve position switch contacts.
These act to initiate a reactor scram through the condenser low vacuum contacts in the scram circuitry (1K11,1K12, 2K11, and 2K12).
As part of the surveillance test, PSH-C was pressurized to 180 psig without the corresponding trip.
The pressure was increased to ascertain the trip point and it was found to operate at 197 psig.
A third stage extraction pressure of 180 psig corresponds-to turbine steam flow of 40% and 197 psig corresponds to a flow of approximately 45%. Therefore, the bypass around the PSL-C and S.V. position switch contacts would have been in effect at 45% turbine flow during power operation instead of 40%.
It should be noted that its associated redundant switch PSH-A performed satisfactorily.
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Abnormal Occurrence No. 50-219/74/30 Page 2 Apparent Cause of Occurrence Possible mishandling of the switches during the maintenance outage and poor instrument repeatability are considered causes for this occurrence.
Analysis of Occurrence The safety significance of this occurrence is minimal since the redundant switch (PSH-A) performed satisfactorily.
In addition, the purpose of the switch is to bypass the reactor scram due to turbine trip at a point when the bypass valves are able to accept the reactor steam production.
The anticipatory scram acts to minimize fuel thermal transients in the event
.of a turbine trip with failure to bypass at power levels in exces; of 40%
of rated turbine steam flow.
Since the plant is designed to withstand this transient, the switch operation at 45% of rated steam flow would, in the event the redundant switch failed to operate, be of no concern.
Corrective Action The switch was recalibrated and tested satisfactorily.
A lower setpoint is being considered to allow for instrument repeatability error.
Failure Data Manufacturer:
Barksdale #B2T-A12SS Range:
Adjustable from 50-1200 psig Proof Pressure:
1800 psig
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