05000298/LER-1980-004, Forwards LER 80-004/03L-0

Forwards LER 80-004/03L-0

ML19294B475
Person / Time
Site:	Cooper
Issue date:	02/08/1980
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19294B476	List: 05000298/LER-1980-004, Forwards LER 80-004/03L-0 05000298/LER-1980-004-03, /03L-0:on 800115,during Normal Operation, Discovered That RHR Valve M018 Was Inoperable.Caused by Failure of GE Relay Coil,Blowing Valve Control Circuit Fuse. Relay Coil Was Replaced & Correct Operation Verified
References
NUDOCS 8002280464
Download: ML19294B475 (2)

LER-1980-004, Forwards LER 80-004/03L-0

Event date:
Report date:
2981980004R00 - NRC Website

text

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c c c,~ue_c e u-,um Nebraska Public Power District^uet%{,$dge{]'"l_ CUSS 800086 February 8, 1980 Mr. K. '.'. S e y f r i t U.S. Suelear Regulatory Cennissien Office of Inspection and Enforcement Region IV 611 Ryan Plaza suite 1000 v. Texas 76011 Arlingt

Dear Sir:

This report is submitted in accordance with Section 6.7.2.B.2 of the Technical Specifications for Cacper Nuclear Station and discusses a reportable occurrence that was discovered on January 15, 1980. A licensee event report form is also enclosed. Report No.: 50-298-80-04 Report Date: February 8, 1980 Occurrence Date: January 15, 1980 Facility: Cooper Nuclear Station Brownville, Nebraska 68321 Identification of Occurrence: A condition which lead to operation in a degraded node permitted by a limiting condition for operation established in Section 3.7.D.2 of the Technical Specifications. Conditions Prior to Occurrence: The reactor was at a steady state power level of approximately 98% of rated thermal power. Description of Occurrence: During normal operation, an operator noticed that the green in-dicating l' t above the control switch for valve RHR-MO-18 was out. The AC control power for the valve was lost, causing the valve to

.a inoperable.

Designation of Apparent Cause of Occurrence: The cause of this occurrence was attributed to a blown fuse in the control circuit of the valve caused by a short in the coil of relay 16A-K31. { s o o 22 s a sr4 t/

Mr. K. V. Seyfrit February 8, 1980 Pa ge 2. Analysis of Occurrence: RER-MO-18 is the inboard isolation valve for the RHR Shutdown Cooling suction from the reactor vessel. RHR-MO-17, the outboard valve, and RHR-MO-18 are closed during reactor operation, and are only open in shutdown cooling when reactor pressure is less than 75 psig. These valves receive a close signal from primary containment isolation system on a Group II isolation. At the time of the f ailure both RHR-MO-18 and RHR-MO-17 were closed. Relay 16A-K31 is a General Electric CR120 relay. It is used to monitor the position of RHR-MO-13 and is part of an electrical interlock to prevent running the RER pumps with all the suction valves closed. Since the normal RHR suction valves were open, failure of this relay did not make the RHR pumps inoperative, nor would it have ptevented the system from performing its function of low pressure injection had it been required. There was no sig-nificant occurrence as a result of this event, nor did it present any adverse consequences from the standpoint of public health and safety.

Corrective Action

The relay coil was replaced with an identical spare and correct operation of the relay verified. Operation of the valve, RER-MO-18, will be verified during the next shutdown because this valve can be open only when reactor pressure is below 75 psig. Sincerely, [ L. C. Lessor Station Suparintendent Cooper Nuclear Station LCL:cg Attach. }}