05000298/LER-1982-025, Forwards LER 82-025/03L-0.Detailed Event Analysis Submitted

Forwards LER 82-025/03L-0.Detailed Event Analysis Submitted

ML20028F086
Person / Time
Site:	Cooper
Issue date:	01/20/1983
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20028F088	List: 05000298/LER-1982-025, Forwards LER 82-025/03L-0.Detailed Event Analysis Submitted 05000298/LER-1982-025-03, /03L-0:on 821222,coil of Reactor Protection Relay 915-5AK8C Overheated.Relay Did Not Fail.Cause Undetermined. Relay Replaced & Proper Operation Verified
References
CNSS-83-0048, CNSS-83-48, NUDOCS 8301310135
Download: ML20028F086 (2)

LER-1982-025, Forwards LER 82-025/03L-0.Detailed Event Analysis Submitted

Event date:
Report date:
2981982025R00 - NRC Website

text

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CNSS830048 9{ 1[N@(MUW/IM3 January 20, 1983

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Mr. John T. Collins, Regional Administrator U. S. Nucl2ar Regulatory Commission Office of Inspection and Enforcement Region IV 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76011

Dear Sir:

This report is submitted in accordance with Section 6.7.2.B.1 of the Technical Specifications for Cooper Nuclear Station and discusses a reportable occur-rence that was discovered on December 22, 1982. A licensee event report form is a.1so enclosed.

Report No.:

50-298-82-25 Report Date:

January 20, 1983 Occurrence Date:

December 22, 1982 Facility:

Cooper Nuclear Station Brownville, Nebraska 68321 Identification of Occurrence:

A condition occurred which resulted in operation in a degraded m ce as permitted by Section 3.1 of the Technical Specifications.

Conditions Prior to Occurrence:

The reactor was at a steady state power of 99% of rated thermal power.

Description of Occurrence:

During normal operation, an operator smelled burning insulation and noticed the overheating of relay 915-5AK8C. The relay, however, remained ene gized.

Designation of Apparent Cause:

The cause of the relay coil overheating could not be determined.

Analysis of Occurrence:

Relay 915-5A-K8C is associated with the Reactor Protection System.

It is one of four relays, each connected to a pressure switch which detects turbine control valves fast closure. This relay is normally energized.

It deenergizes when the turbine control valves close fast and provides a signal to the scram logic.

Complete failure of the relay coil would have caused a half scram.

Ob B301310135 830120 PDR ADOCK 05000298 S

PDR l

Mr. John T. Collins January 20, 1983 Page 2 The relay was immediately isolated by pulling its fuse which resulted in n

a half scram. Therefore, this abnormal occurrence did not degrade the reactor safety.

This is the third failure of HFA type relays at'CNS. One previous failure was reported in LER 82-21, the other was not reportable.

Corrective Action

The relay was immediately replaced and its proper operation verified.

New relay coils are being purchased for replacement in similar relays.

Sir.cerely, L. C. Lessor Station Superintendent Cooper Nuclear. Station LCL:cg Enc.

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