ML17059A628
| ML17059A628 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 01/13/1995 |
| From: | Brinkman D Office of Nuclear Reactor Regulation |
| To: | Sylvia B NIAGARA MOHAWK POWER CORP. |
| Shared Package | |
| ML17059A629 | List: |
| References | |
| GL-94-03, GL-94-3, TAC-M90102, NUDOCS 9501250424 | |
| Download: ML17059A628 (8) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 13, 1995 Mr. B. Ralph Sylvia Executive Vice President, Nuclear Niagara Hohawk Power Corporation Nine Hile Point Nuclear Station P. 0.
Box 63
- Lycoming, NY 13093
Dear Hr. Sylvia:
SUNECT:
RESPONSE
TO GENERIC LETTER (GL) 94-03, "INTERGINULAR STRESS CORROSION CRACKING OF CORE SHROUDS IN BWRs,"
FOR NINE HILE POINT NUCLEAR STATION UNIT NO.
1 (TAC NO. M90102)
By letter dated August 23,
- 1994, Niagara Mohawk Power Corporation (NMPC),
responded to'Generic Letter (GL) 94-03, "Intergranular Stress 'Corrosion Cracking of Core Shrouds in BWRs," for Nine Hile Point Nuclear Station Unit
.*'o.
1 (NMP-1).
The NRC staff requested in GL 94-03 that licensees take the following actions with respect to their core shrouds:
- 1) inspect the core shrouds in BWR plants no later than the next refueling outage,
- 2) perform materials related and plant specific consequence safety analyses with respect to core shrouds,
- 3) develop core shroud inspection plans which address inspection of all core shroud welds and which takes into account the latest available inspection technology,
- 4) develop plans for evaluation and/or repair of their core shrouds, and 5) work closely with the BWR Owners Group with respect to addressing intergranular stress corrosion cracking of BWR internals.
The NRC staff required that licensees
- submit, under oath or affirmation, the following information in response to GL 94-03 within 30 days of the date of issuance:
- 1) a schedule for inspection of their core shrouds, 2) a safety
- analysis, including a plant specific safety analysis as appropriate, which supports continued operation of their facilities'until inspections are conducted,
- 3) drawings of the core shroud configurations, and 4) a history of shroud inspections completed to date.
The NRC staff also required that licensees
- submit, under oath or affirmation, no later than 3 months prior to performing their core shroud inspections, their scope for inspection of their core shrouds and their plans for evaluating and/or repairing their core shrouds based on inspection results.
The NRC staff further required licensees to submit, under oath or affirmation, their core shroud inspection results within 30 days of completing their shroud examinations.
The NRC staff has completed its review of NMPC's response.
Based on the staff's review of NMPC's response to GL 94-03, and in regard to the information that was requested to be submitted within 30 days of the date of issuance of the GL, the staff has determined that NHPC has provided the necessary information for the staff to complete its review.
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B. Sylvia January 13, 1995 The staff concludes that based on an assessment of the IGSCC susceptibility factors pertaining to the core shroud material properties, fabrication, and the past operational history as well as the industry-wide inspection experiences, extensive cracking in the NHP-1 core shroud cannot be ruled out.
However, the core shroud cracking at NHP-1 is expected to be bounded by that of Oyster Creek; since both units were fabricated by the same vendor during the same time period, and NHP-1 had better water chemistry than that of Oyster Creek in the early five fuel cycles.
Oyster Creek recently completed its core shroud inspection of welds Hl through H7.
Extensive cracking was found at weld H4, however, the results of preliminary sizing showed that the cracks were not sufficiently deep to compromise structural integrity with the shroud.
Based on previous core shroud inspections at NHP-1 and the recent Oyster Creek inspection results, NHP-1 core shroud is not likely to contain cracks which would compromise the structural integrity of the core shroud during the remainder of the current fuel cycle.
In addition, other BMRs with core shrouds considered more susceptible to IGSCC have not identified any 360'hrough-wall cracking during inspections.
Per the reporting requirements of GL 94-03, NHPC has submitted (by letter dated November 11, 1994) a plan for inspecting the NHP-1 core shroud during the refueling outage scheduled to begin in February 1995.
NRC staff review of this inspection plan is in progress.
NHPC will be notified regarding our evaluation of this plan in separate correspondence.
Sincerely, Docket No.
50-220
Enclosure:
Safety Evaluation cc w/encl:
See next page Donald S. Brinkman, Senior Project Hanager Project Directorate I-1 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation
B. Ralph Sylvia Niagara Hohawk Power Corporation CC:
Hark J. Wetterhahn, Esquire Winston 8 Strawn 1400 L Street, NW Washington, DC 20005-3502 Supervisor Town of Scriba Route 8, Box 382
- Oswego, NY 13126 Hr. Louis F. Storz Vice President Nuclear Generation
'iagara Mohawk Power Corporation Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093 Resident Inspector U.S. Nuclear Regulatory Commission P.O.
Box 126
- Lycoming, NY 13093 Gary D. Wilson, Esquire Niagara Mohawk Power Corporation 300 Erie Boulevard West
- Syracuse, NY 13202 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Ms.
Donna Ross New York State Energy Office 2 Empire State Plaza 16th Floor
- Albany, NY 12223 Nine Mile Point Nuclear Station Unit No.
1 Hr. Richard B. Abbott Unit 1 Plant Manager Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093 Hr. David K. Greene Manager Licensing Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093 Charles Donaldson, Esquire Assistant Attorney General New York Department of Law 120 Broadway New York, NY 10271 Hr. Paul D.
Eddy State of New York Department of Public Service Power Division, System Operations 3 Empire State Plaza
- Albany, NY 12223 Hr. Hartin J.
McCormick, Jr.
Vice President Nuclear Safety Assessment and Support Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093
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