ML18067A563

Forwards LER 96-013,Suppl 1 Re DC Breaker Failure During Testing for as-found Trip Setting.Three New Commitments, Listed

ML18067A563
Person / Time
Site:	Palisades
Issue date:	06/03/1997
From:	Thomas J. Palmisano CMS ENERGY CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18067A564	List: ML18067A563 ML18067A565
References
NUDOCS 9706100145
Download: ML18067A563 (3)

Text

A CMS Energy Company Palisades Nuclear Plant Tel: 616 764 2296 27780 Blue Star Memorial lfighway Fax: 616 764 2425

. Covert, Ml 49043

~J.hlmlAoo Site Vice President June 3, 1997

• • *** *U:S:**Nuclear Regulatory Commission*

Oocument Control Desk

• Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT LICENSEE EVENT REPORT 96.;013 SUPPLEMENT*1, DC BREAKER FAILURE DURING TESTING FOR AS-FOUND TRIP SETTING .

Licensee Event Report (lER)96-013 Supplement 1 is attached. This event is reportable to the NRC in accordance with 10CFR50.73(a)(2)(v) as a condition that alone could have prevented the fulfillment of the safety* function* of structures or *systems. This supplement provides* results of additional component testing, event root cause and safety significance.

SUMMARY

OF COMMITMENTS This Supplement contains three new commitments:

1. For high safety significant systems (defined by Palisades Procedure EM-25 "Maintenance Rule"), system engineers will perform reviews to determine if preventive maintenance (PM) is required bi.It not beirig performed. The reviews will consider sources such as plant Preventive* Maintenance Optimization, Deferred Maintenance, and. Industry Experience, as applicable. Objectives are to determine:

1) if justification is adequate for not having implemented pre-identified plant PM, 2) if deferred plant PM should be reactivated to maintain system integrity, and 3) if* \

any additional PM should be performed as indicated by conditions or events / ';)?

throughout the industry. *  :::;: ~

• 1 9706100145 970603 '.* 1111m lW llRIJm 111111DI1m l(U PDR ADOCK 05000255 S PDR;:..

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• 2 Following completion of these reviews, the Maintenance Rule Expert Panel will

.review the input from each system engineer to validate the findings. The system engineer and expert panel reviews will be completed by July. 1, 1997.

2 By July 1, 1997, a review of open industry experience documents greater than one year old will be completed to determine if there are any significant items similar to the molded-case Circuit breaker (MCCB) issue which have not been resolved.in a timely manner.

3. A program will be developed by December 1, 1997 for periodic testing of MCCBs. *

. This schedule assures* that results of equipment maintenance reviews identified above will be available and factored into testing program development as necessary.

This.Supplement closes a commitment to determine the root ca.use for the event, and the safety significance of as-found conditions. The root causes for the failure to trip have been determined to be hardening of breaker lubrication which restricted movement of breaker internal components, and an oversight ofthe plant's preventive maintenance system to * "'

.* identify degrading *breaker conditions. Safety .significance was. determined, and although. a c.ommon mode failure affecting redundant' DC distribution panels could have occurred, sufficient *equipment would have remained in service to allow operators to reach and

• rrlaint~in a.safe plant hot shutdown condiUon. The original LER commitment closed is:

"Investigation will continue to test the remaining molded-case circuit breakers***

removed from DC distribution panels D11-1, D11-2 *. 021-1 and 021-2 to determine a root cause for the failure to trip. Safety significance of the.as-found conditions will be reassessed as part of that investigation.", : .

. CC ** Administrator, Region Ill, USNRC Project Manager; NRR, USNRC NRC Resident Inspector - Palisades

• Attachment

... ATTACHMENT

. CONSUMERS ENERGY COMPANY PALISADES PLANT

• DOCKET 50-255 LICENSEE EVENT REPORT 96-013 _SUPPLEMENT 1

• DC BREAKER FAILURE DURING TESTING FOR AS*FOUND TRIP SETTiNG

-21' pages