05000298/LER-1982-017, Forwards LER 82-017/03L-0.Detailed Event Analysis Submitted

Forwards LER 82-017/03L-0.Detailed Event Analysis Submitted

ML20062M658
Person / Time
Site:	Cooper
Issue date:	08/10/1982
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20062M661	List: 05000298/LER-1982-017, Forwards LER 82-017/03L-0.Detailed Event Analysis Submitted
References
CNSS820452, NUDOCS 8208200166
Download: ML20062M658 (2)

LER-2082-017, Forwards LER 82-017/03L-0.Detailed Event Analysis Submitted

Event date:
Report date:
2982082017R00 - NRC Website

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D b Mr. John T. Collins, Regional Administrator ,,

U.S. Nuclear Regulatory Commission -

Region IV 611 Ryan Plaza Drive eg$

Suite 1000 Arlington, Texas 76011

Dear Sir:

This report is submitted in accordance with Section 6.7.2.B.2 of the Technical Specifications for Cooper Nuclear Station and discusses a reportable occurrence that was discovered on July 13, 1982. A licensee event report form is also enclosed.

Report No.: 50-298-82-17 Report Date: August 10, 1982 Occurrence Date: July 13, 1982 Facility: Cooper Nuclear Station Brownville, Nebraska 68321 Identification of Occurrence:

A condition which resulted in operation in a degraded mode per-mitted by a limiting condition for operation established in Section 3.5.F.2 of the Technical Specifications.

Conditions Prior to Occurrence:

The reactor was at a steady state power level of approximately 86%

of rated thermal power. #1 Diesel Generator (DG) was inoperable.

(Reference LER 82-016.)

Description of Occurrence:

After satisfactorily performing an overspeed test on #2 DG, the diesel tripped before it could be loaded. The DG was restarted, loaded, and again tripped. #2 DG was declared inoperable.

Designation of Apparent Cause of Occurrence:

The failure of #2 DG was due to binding in the low lube oil pres-sure switch.

f 8208200166 820010 e

PDR ADOCK 05000298 S PDR

Mr. John T. Collins August 10, 1982 Page 2.

Analysis of Occurrence:

, The low lube oil pressure switch is an AMOT Model 1672ELA-1 pres- ,

sure sensing valve. The valve is blocked out on a normal diesel startup. Af ter the engine is running, the pressure switch sensing line will close when proper oil pressure is attained. An overspeed trip test had just been satisfactorily completed to verify proper operation of the safety trip valve (reference LER 82-16). After #2 DG was declared inoperable and preparations made for a reduction in reactor power, the low lube oil pressure switch was tested.

Indication was that the vent valve was not remaining closed al-lowing sensing pressure to vent off. The valve was then exercised several times with no further problems noted. #2 DG was then operationally tested and returned to service. ,

Failure of this switch under accident conditions would not have made the diesel inoperable. On an automatic (emergency) start all safety shutdowns operated by 30 psig control air are valved out.

This occurrence presented no adverse consequences from the stand-point of public health and safety.

Corrective Action:

The low lube oil pressure switch was replaced during a plant shut-down on July 14, 1982. The switch will be returned to the vendor for inspection and overhaul.

The same switch on #1 DG was functionally tested and calibrated i during the recent annual diesel generator inspection.

Sincerely, L. C. Lessor Station Superintendent Cooper Nuclear Station LCL cg Attach.

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