05000298/LER-1982-026, Forwards LER 82-026/03L-0.Detailed Event Analysis Submitted

Forwards LER 82-026/03L-0.Detailed Event Analysis Submitted

ML20079M478
Person / Time
Site:	Cooper
Issue date:	02/15/1983
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20079M481	List: 05000298/LER-1982-026, Forwards LER 82-026/03L-0.Detailed Event Analysis Submitted
References
CNSS830113, NUDOCS 8302230712
Download: ML20079M478 (2)

LER-2082-026, Forwards LER 82-026/03L-0.Detailed Event Analysis Submitted

Event date:
Report date:
2982082026R00 - NRC Website

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CNSS830113 February 15, 1983 M M.__W, W;4 Mr. John T. Collins, Regional Administrator  :

U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement F B l 7 m L 'l!; i Region IV _M 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76011

Dear Sir:

O-This report is submitted in accordance with Section 6.7.2.B.3 of the Technical Specifications for Cooper Nuclear Station and discusses an event that occurred on December 22, 1982. The event was considered not reportable during the January 20, 1983 SORC Meeting. The event had also been discussed with the Resident Inspector between the date of event and the SORC Meeting. Further inforuation has been gathered in regard to testing requirements and the event is considered reportable as of February 11, 1983. A licensee event form is also enclosed.

Report No.: 50-298-82-26 Report Date: February 15, 1983 Occurrence Date: December 22, 1983 Facility Cooper Nuclear Station Brownville, Nebraska 68321 Identification of Occurrence:

A condition occurred which resulted in operation of the plant in a degraded mode for a period of time without promptly determining that the diesel generators were operable as required by Section 3.9.B.1 of the Technical Specifications.

Conditions Prior to Occurrence:

The reactor was operating at a steady state power of 99% of rated thermal power. Relay 915-5A-K8C was deenergized for repair. This relay is associated with the Reactor Protection System and a half scram was automatically inserted as a result of securing power in order to make the repair. The circumstances involving this relay repair were reported in report number 50-298-82-25 dated January 20, 1983. Normal power, startup power, preferred (f9KV line) and alternate emergency power (diesel generators) were all available to automatically supply the critical buses. The dispatcher had requested the 69KV line be taken out of service for Omaha Public Power District to perform an emergency repair.

Wind was causing some lines to whip with arcing potential.

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Mr. Jc hn T. Collins February 15, 1983 Page 2' Description of Occurrence:

The 69KV line was taken out of service at 0923 hours0.0107 days <br />0.256 hours <br />0.00153 weeks <br />3.512015e-4 months <br /> on December 22, 1982 for emergency maintenance. The diesel generators should have been tested for operability in a timely manner. However,-testing was not started for about eight hours.

Designation of Apparent Cause:

Although the exact cause cannot be determined, it appears that several licensed personnel erred in not getting the testing started sooner.

Analysis of Occurrence:

The diesel generators were proven to be operable eight hours after the event and thus, were undoubtedly operable while the 69KV line was out of service. Given the half scram conditions prior to the occurrence and a busy day sci.edule, a determination of exactly when to test the diesels was not made. Several factors are believed to have contributed to this oversight. Perhaps operator overreaction to the dispatcher's request which seemed unusually urgent was involved. The wording of Technical Specification 3.9.B.1 may have also been a contributing factor. A special surveillance test being conducted af ter a critical system component replacement could have also contributed. The 69KV line was actually taken out at 0923 hours0.0107 days <br />0.256 hours <br />0.00153 weeks <br />3.512015e-4 months <br /> and placed back in service at 1346 hours0.0156 days <br />0.374 hours <br />0.00223 weeks <br />5.12153e-4 months <br /> the same day. Apparently, the short four hoar outage failed to trigger the licensed personnel to operate the diesel generators. When the -

station superintendent became aware of the situation, he directed that the diesels be tested. Testing was completed on both diesel generators by 1930 hours0.0223 days <br />0.536 hours <br />0.00319 weeks <br />7.34365e-4 months <br /> of the same day.

Corrective Action:

Licensed operators have been re-inforned of the proper testing require-ments for diesel 6enerators whenever the 69KV line is to be taken out of service.

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