ML17059C104
| ML17059C104 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 06/25/1998 |
| From: | Bajwa S NRC (Affiliation Not Assigned) |
| To: | Mueller J NIAGARA MOHAWK POWER CORP. |
| Shared Package | |
| ML17059C105 | List: |
| References | |
| TAC-MA2066, NUDOCS 9807010127 | |
| Download: ML17059C104 (8) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON> D C 205R~01 3une 25, 1998 Mr. John H. Mueller Chief Nuclear Officer Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station Operations Building, Second Floor Lycoming, NY 13093
SUBJECT:
FLAWINDICATIONIN FEEDWATER INLET NOZZLE N4D SAFE END-TO-NOZZLE WELD BUTTER, NINE MILEPOINT NUCLEARSTATION, UNIT NO. 2 (TAC NO.
MA2066)
Dear Mr. Mueller:
By letter dated June 17, 1998, as supplemented June 23, 1998, Niagara Mohawk Power Corporation (NMPC) submitted an evaluation of an indication in the feedwater nozzle-to-safe end weld butter (Weld 2RPV-KB20) observed by'ultrasonic testing (UT) during the current 1998 refueling outage (RFO-6) for Nine Mile Point Nuclear Station, Unit 2 (NMP2). The indication, which contacts the inside surface of the nozzle, is circumferentially oriented in the Alloy 182 weld butter, with a length of 5.3 inches and depth of 0.29 inch. Although field experience and NMPC's rereview of the earlier 1990 and 1995 UT results suggest that the indication is probably fabrication related and has not grown during service, NMPC provided a fracture mechanics evaluation that was performed assuming the crack to be an actively growing intergranular stress corrosion crack. The evaluation includes a crack growth prediction and allowable flaw calculation, using both austenitic and ferritic piping methodologies, to demonstrate the structural integrity of the nozzle-to-safe end weld location for at least the next operating cycle (16,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />).
Pursuant to Generic Letter (GL) 88-01, "NRC Position on Intergranular Stress Corrosion Cracking (IGSCC) in BWR Austenitic Stainless Steel Piping," NMPC requested that the NRC approve the evaluation before resumption of NMP2 operation (currently scheduled for June 26, 1998).
The NRC staff has completed its review of NMPC's submittals.
Based on the information submitted and the NRC staffs independent verification of NMPC's calculations, the NRC staff concludes that the nozzle weld with the flaw is acceptable for continued operation without repairs for the next operating cycle of 16000 hours.
98070iOi27 980625 PDR ADQCK 050004%0 P
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3une 25, 1998 J. H. Mueller The NRC staff's Safety Evaluation is contained in the enclosure.
Ifyou have any questions regarding this matter, please contact Mr. Darl Hood by phone at (301)-415-3049 or by electronic mail at dsh@nrc.gov.
Sincerely, Original Signed by:
Singh S. Bajwa, Director Project Directorate I-1 Division of Reactor Projects - I/II
.Office of Nuclear Reactor Regulation Docket No. 50-410 II
Enclosure:
Safety Evaluation ccw/encl: See next page Distribution:
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PUBLIC PDI-1 Reading OGC ACRS LDoerflein, RGN-I DHood SBajwa SSheng KWichman CCarpenter ESullivan RHermann WKoo DOCUMENT NAME: G:>NMP2iNM2A2066.LTR To receive a copy of this document, indicate in the box: "C" ~ Copy without enclosures "E" ~ Copy with enclosures "N" ~ No copy OFFICE PH: PDI-1 NAHE DHood/1CC3>S DATE 06~98 LA;PDI-1 SLittl 06/
/98 D: PDI-1 SBajwa 06/1 98 OFFICIALRECORD COPY
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J. H. Mueller The NRC staff's Safety Evaluation is contained in the enclosure.
Ifyou have any questions regarding this matter, please contact Mr. Dari Hood by phone at (301)-415-3049 or by electronic mail at dsh@nrc.gov.
Sincerely, Singh S. Bajwa, Director Project Directorate l-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket No. 50-410
Enclosure:
Safety Evaluation cc w/encl: See next page
1
John H. Mueller
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Niagara Mohawk Power Corporation CC:
Regional Administrator, Region I U. S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Resident Inspector Nine Mile Point Nuclear Station P.O. Box 126 Lycoming, NY 13093 Mr. Jim Rettberg NY State Electric 8 Gas Corporation Corporate Drive Kirkwood Industrial Park P.O. Box 5224 Binghamton, NY 13902-5224 Mr. John V. Vinquist, MATS Inc.
P.O. Box 63 Lycoming, NY 13093 Supervisor Town of Scriba Route 8, Box 382 Oswego, NY 13126 Mr. Richard Goldsmith Syracuse University College of Law E.l. White Hall Campus
- Syracuse, NY 12223 Nine Mile Point Nuclear Station Unit No. 2 Charles Donaldson, Esquire Assistant Attorney General New York Department of Law 120 Broadway New York, NY 10271 Mr. Timothy S. Carey Chair and Executive Director State Consumer Protection Board 5 Empire State Plaza, Suite 2101 Albany, NY 12223 Mark J. Wetterhahn, Esquire Winston 8 Strawn 1400 L Street, NW.
Washington, DC 20005-3502 Gary D. Wilson, Esquire Niagara Mohawk Power Corporation 300 Erie Boulevard West
- Syracuse, NY 13202 Mr. F. WilliamValentino, President New York State Energy, Research, and Development Authority Corporate Plaza West 286 Washington Avenue Extension Albany, NY 12203-6399