ML17059A519

Forwards Response to Request for Suppl Info Re GL 94-03, Intergranular Stress Corrosion Cracking of Core Shrouds in Bwrs. W/One Oversize Drawing

ML17059A519
Person / Time
Site:	Nine Mile Point
Issue date:	11/04/1994
From:	Terry C NIAGARA MOHAWK POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML17059A520	List: ML17059A519 ML17059A521 ML17059A522 ML18040A297
References
GL-94-03, GL-94-3, NMP1L-0874, NMP1L-874, TAC-M90102, NUDOCS 9411160218
Download: ML17059A519 (4)

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ACCESSION NBR:9411160218 DOC.DATE: 94/11/04 NOTARIZED: NO DOCKET FACIL:50-220 Nine Mile Point Nuclear Station, Un't 1, Niagara Powe 05000220 AUTH. NAME AUTHOR:AFFILIATION TERRY,C.D. Niagara Mohawk Power Corp.

RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Forwards response to request. for suppl info re GL 94-03, "Intergranular Stress Corrosion Cracking of Core Shrouds in BWRs."

DISTRIBUTION CODE: A018D COPIES RECEIVED LTR ENCL SIZE:

TITLE: GL 94-03 Intergranular Stress Corrosion Cracking of Core Shrouds in B NOTES: lg RECIPIENT " COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PM/BRINKMAN,D. 1 1 INTERNA : FIL ~CENTER~01'RR/DE/EME 1 1 NRR/DE/EMCB 1 1 B 1 1 NRR/DORS/OEAB 1 1 NRR/DSSA/SRXB 1 1 EXTERNAL: NRC PDR 1 1 NOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE iVASTE! CONTACI'TIIE DOCUiIE4T CONTROL DESK, ROOM P!-37 (EXT. 504-2083 ) TO ELIXIINATEYOUR NAi!E F ROTI DISTRIBUTION LISTS FOR DOCUMENTS YOU DON"I'LED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 7 ENCL 7

g MQogl+5fK NINE MILE POINT NUCLEAR STATION/P.O. BOX 63, LYCOMING, NEW YORK 13093/TELEPMONE (315) 343-2110 November 4, 1994 NMP1L 0874 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 RE: Nine Mile Point Unit 1 Docket No. 50-220 DPR-63

Subject:

Response to Request for Supplemental Information Regarding Generic Letter 94-03, "Intergranular Stress Corrosion Cracking of Core Shrouds in Boiling Water Reactors" (TAC No. M90102)

Gentlemen:

By letter dated August 23, 1994 (NMP1L 0852), Niagara Mohawk provided a response to Generic Letter 94-03, "Intergranular Stress Corrosion Cracking of Core Shrouds in Boiling Water Reactors," for Nine Mile Point Unit 1 (NMP1). Additional information was provided in Niagara Mohawk's September 26, 1994 letter (NMP1L 0863) in response to the Staff's request for additional information of September 16, 1994. At the Staff's request, Niagara Mohawk made a presentation at NRR Headquarters on October 14, 1994 to further address the NMP1 core shroud, specifically with regard to the H8 shroud weld. By letter dated October 26, 1994, the Staff requested that Niagara Mohawk supplement its response to Generic Letter 94-03 based on the results of the Oyster Creek core shroud inspection. The enclosure to this letter responds to the Staff's October 26, 1994 request for supplemental information.

The detailed analyses provided in this supplement confirm our Generic Letter 94-03 submittal conclusion that continued operation of NMP1 is justified until the scheduled February 1995 refuel outage. This conclusion remains based on the extremely low probability that the core shroud would fail to meet its design basis structural integrity margin during this time period, coupled with the extremely low overall probabilistic risk estimate.

Very truly yours, C. D. Terry Vice President - Nuclear Engineering 9411160218 941104 PDR ADOCK 05000220 PDR

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