ML20134F428

Provides Response to NRC Bulletin 95-002, Unexpected Clogging of RHR Pump Strainer While in Suppression Pool Cooling Mode

ML20134F428
Person / Time
Site:	Oyster Creek
Issue date:	10/29/1996
From:	Roche M GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
6730-96-2331, IEB-95-002, IEB-95-2, NUDOCS 9611050243
Download: ML20134F428 (3)

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I l GPU Nuclear,Inc.

A U.S. Route #9 South NUCLEAR Post Office Box 388 Forked River, NJ 08731-0388 Tel 609-971-4000 October 29,19%

6730-96-2331 U. S. Nuclear Regulatory Commission Attn.: Document Control Desk Washington, DC 20555

Subject:

Oyster Creek Nuclear Generating Station Docket No. 50-219 NRC Bulletin 95-02 On October 17,1995, the USNRC issued Bulletin 95-02 " Unexpected Ciogging of a Residual Heat Removal (RHR) Pump Strainer While Operating in Suppression Pool Cooling Mode."

This bulletin required a 30 day response which was docketed by the Oyster Creek Nt. 4 ear Generating Station on November 16,1995. The bulletin also required an additional response when the recommended actions described in the bulletin were completed. This letter provides the reply to that second reporting requirement.

If any additional information or assistance is required, please contact Mr. John Rogers of my staff at 609.971.4893.

Very truly yours, h

Michael Roche Vice President and Director Oyster Creek MBR/JJR cc: Oyster Creek NRC Project Manager Administrator, Region i Senior Resident inspector - /

Tb N l 9611050243 961029 PDR ADOCK 05000219 G PDR l

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By letter dated November 16,1995, the Oyster Creek Nuclear Generating Station submitted the required 30 day report in response to NRC Bulletin 95-002. The letter consisted of five i NRC recommended actions and the respective GPU Nuclear responses. As a result of actions completed prior to and during the recent 16R refueling outage, the response to request 3 has 4

been updated. The most recent information is supplied below.

NRC Requested Action No. 3 Schedule a suppression pool cleaning. The schedule for cleaning the pool should be consistent with the operability evaluation in requested action 1 above. In addition, a program for periodic cleaning of the pool should be established, including procedures for cleaning of the

pool, criteria for determining the appropriate cleaning frequency, and criteria for evaluating the adequacy of the pool cleanliness.

GPUN Response No. 3 A torus inspection and cleaning are scheduled for each refueling outage. The scope and type of torus cleaning is determined by the results of the inspection. The inspection is normally conducted using a video camera in a small, remotely controlled submarine. Materials removed from the torus are evaluated to assist in determining the effectiveness of the foreign material j exclusion program.

During 16R, each of the three Emergency Core Cooling System (ECCS) suction strainers were inspected and videotaped by divers. Each was found in excellent condition, with all holes free of debris, and no accumulation of fibrous material. A very thin film of sludge coating the strainers, as well as the rest of the torus components, posed no obstruction to the flow through the strainers. The strainers were vacuum cleaned during the desludging operations.

A specification for destudging the torus was developed and implemented. Torus sludge was removed and weighed using divers and a vacuum cleaning system. In the original submittal of November 16,1995, GPU Nuclear conservatively estimated the sludge accumulation rate to be 125 lbs per year. Based on an analysis of the desludging operations during 16R, this number has been recalculated to be approximately 50 lbs per year. Future destudging operations will be scheduled based on the accumulation rate and the assumptions used for the modification designed to meet Regulatory Guide 1.82, Revision 2, criteria. This desludging schedule will commence with the next refueling outage,17R.

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e 6730-E2331 Attachment i page 2 T

l The results of the suppression pool cleaning revealed an amount of small debris had accumulated over the years. Various tools, small nuts, bolts, and washers, wire, broken glass i duct tape, plastic,6 inch by 6 inch wipe towels, etc. were removed. This cleaning essentially

' baselined the cleanliness of the suppression pool. Existing controls including downcomer covers, foreign material exclusion procedures, and employee training have been effective in reducing the foreign material introduced into the suppression pool.

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