ML20084U663

Responds to Info Notice 91-022, Four Plant Outage Events Involving Loss of AC Power or Coolant Spills. Actions Taken to Date Encompass & Exceed Actions Suggested in Info Notice

ML20084U663
Person / Time
Site:	Oyster Creek
Issue date:	04/11/1991
From:	J. J. Barton GENERAL PUBLIC UTILITIES CORP.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
C321-91-3001, IEIN-91-022, NUDOCS 9104220097
Download: ML20084U663 (2)

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GPU Nuclear Corporation Nuclear =e NEI **

Forked River, New Jersey 087310388 609 971 4000 Wnter's Direct Dial Number:

April 11, 1991 C321-91-3001 Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Attn.: Document Control Desk Washington, DC 20555 References Information Notice 91-22,*Four Plant Outage Events Involving Loss of AC Power or Coolant Spille" Letter; Murley (NRC) tc Barton (GPUN) dated March 25, 1991 Dear Sir Subject Oyster Creek Nuclear Generating Station Docket No. 50-219 Management Review of Information Notice 91-22 On March 19, 1991, the USNRC issued Information Notice (IN) 91-22, referenced above. Included in IN 91-22 was a discussion of the degradation in electrical system redundancy which occurred at the Oyster Creek Nuclear Generating Statica on March 9, 1991. Although the discussion in IN 91-22 was accurate, it was a preliminary wmmary of the event, and therefore incomplete. Thie letter is being written for two purposes: 1) to update the information presented by the NRC in IN 91-22; and 2) to provide a CPU Nuclear management response to the

-USNRC letter referenced above.

The event.at Oyster Creek was initiated wher. a Diesel Generator was declared inoperable after failing a routine surveillance test. Immediate corrective actions were taken to comply with existing Technical Specifications.

Additionally, access to areas which could threaten the remaining normal power path was restricted, and the electric utility System Dispatcher was contacted to ensure maximum reliability for the remaining source of power. Plant conditions were stabilized and maintained while additional risk minimization actions were taken.

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C3al-91-3001 Page 2 Portable diesel generators of sufficient capacity were located and brought to the site. Existing procedures for alternate sources of power were reviewed and evaluated. It was determined that several alternate sources of electric power could be made available in a relatively short period of time.

Concurrently, alternate means to provide both water inventory and core cooling without electric power were identified and prioritized. Aggressive recovery action to restore the inoperable Diesel Generator worked around the clock.

After the restoration of the failed Diesel Generator, an Independent safety Review of the event was initiated to determine if additional mitigating factors could have been implemented or pre-staged. Additionally, the Director-Oyster Creek established an Outage Risk Reduction Team to assess the ongoing and planned conduct of the refueling outage and determine if appropriate limitations and controle were in place to avoid unnecessary increases in risk.

The report from the Independent Safety Review Group was completed on March 25, 1991. The Outage Risk Reduction Team identified four " vital functions" (core inventory, core cooling, containment, and electric power) which need to be considered whenever a change to system availability is planned. These two efforts are presently under manageme.it review to determina if additional improvements in risk minimization can be implemented.

Separate from the internal GPUN efforts, the NRC sent an Augmented Inspection Team (AIT) to collect information and evaluate this eve.it. The AIT proposed a few areas where administrative improvements could be mate, and suggested that outage planning in general should consider risk in scheduling system outages.

Finally, GPUN has reviewed IN 91-22 and has determined that the actions taken at Oyster Creek to date encompass and exceed those suggested in the Information Notice.

If any additional information would be of assistance, please call Mr. John Rogers at 609-971-4893.

Very tr y yours,, f

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ohn J. on ir ctor - O er Creek JJB/JJR (21913001) cc Document Control Desk, USNRC Administrator, Region I Senior Resident Inspector Oyster Creek NRC Project Manager

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