ML20209G200
| ML20209G200 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 07/09/1999 |
| From: | Terry C NIAGARA MOHAWK POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML18040A368 | List: |
| References | |
| GL-94-03, GL-94-3, NMP1L-1449, NUDOCS 9907190081 | |
| Download: ML20209G200 (1) | |
Text
NiagarahMohawk' cui o. Tony July 9,1999 enon :3i5.349ms3 i
vice President NMP1L 1449 Fax: 315.349.4753 i
Nuclear Safety Assessment and Support 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:
Generic Letter 94-03, "Intergranular Stress Corrosion Cmcking of Core Shmuds in Boiling Water Reactors' Gentlemen:
During refueling outage number 15 (RFO15), Niagara Mohawk Power Corporation (NMPC) performed inspections of the Nine Mile Point Unit 1 (NMP1) core shroud. The purpose of this letter is to provide core shroud inspection results as required by Generic Letter 94-03 and Boiling Water Reactor Vessel Internals Project Report, titled "BWR Core Shroud Inspection and Flaw Evaluation Guideline (BWRVIP-01)." These inspection results are provided in an attachment to this letter.
The inspection of the core shroud vertical and horizontal welds satisfied the scope of inspections as approved by the NRC in their letter dated March 24,1999. The results of these inspections demonstrate that the American Society of Mechanical Engineer required structural margins were satisfied for the previous operating cycle and would continue to be satisfied for an additional 2 year operating cycle without any repairs to the core shroud welds.
Inspection results for the V10 weld showed the greatest crack depth change of all the examined welds; however, all examined welds remain bounded by the structural analysis of the core shroud. NMPC dcsided to pre-emtively repair the V9 and V10 welds using a contingency repair previously approved by the Staff.
As acknowledged by the Staff in a letter dated March 24,1999, NMPC will define the scope of the core shroud reinspection at least three months prior to the start of RFOl6.
Very t,
- yours, 190028 g
9907190001 990709 PDR ADOCK 05000220 Carl D. Terry f
G PDR Vice President j
Nuclear Safety Assessment & Support CDT/KWK/ kap
/
Attachment xc:
Mr. H. J. Miller, Regional Administrator, Region I Mr. S. S. Bajwa, Section Chief PD-I, Section 1, NRR ThK Mr. G. K. Hunegs, NRC Senior Resident Inspector k\\
Mr. D. S. Hood, Senior Project Manager, NRR Records Management Nme Mde Point Nuclear Station, P0. Box 63, Lycoming, New York 13093 0063
- www.nimo.com i
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