ML17059C657
| ML17059C657 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 04/30/1999 |
| From: | Bajwa S NRC (Affiliation Not Assigned) |
| To: | Mueller J NIAGARA MOHAWK POWER CORP. |
| Shared Package | |
| ML17059C659 | List: |
| References | |
| TAC-MA4701, NUDOCS 9905050283 | |
| Download: ML17059C657 (10) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-000I April 30, 1999 Mr. John H. Mueller Chief Nuclear Officer Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station Operations Building, Second Floor Lycoming, NY 13093
SUBJECT:
ALTERNATIVEREPAIR OF THE CORE SHROUD VERTICALWELDS, NINE MILEPOINT NUCLEAR STATION, UNIT NO. 1 (TAC NO. MA4701)
Dear Mr. Mueller.
By letter dated February 3, 1999, as supplemented by letter dated April 14, 1999, Niagara Mohawk Power Corporation (NMPC) described a repair plan for the core shroud vertical welds at Nine Mile Point Nuclear Station, Unit No. 1 (NMP1). The repair plan was submitted as a contingency which, subject to NRC staff approval, would be installed if needed based upon inspection results.
The repair design is consistent with, and meets the guidelines of the Boiling Water Reactor Vessel and Internals Project's document BWRVIP;02, "Core Shroud Repair Design Criteria," as approved by the NRC staff in a safety evaluation (SE) dated September 29, 1994.
Because the proposed core shroud repair is not included under the definition for repair or replacement specified in Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), NMPC requested that the NRC staff approve the proposed core shroud repair as an alternative repair pursuant to 10 CFR 50.55a(a)(3)(i).
Your submittals address vertical welds V4, V9, and V10. The repair involves no welding of the core shroud.
Rather, the repair is basically a clamp consisting of a plate with attached pins that are inserted into holes, machined in the shroud by the Electric Discharge Machining process, on both sides of the flawed vertical weld. The clamps bridge across the flawed vertical weld and transmit the pressure load normally transmitted through the vertical weld.
Two clamps would be used for the V9 weld, two clamps for the V10 weld, and one clamp for the shorter V4 wetd. The repair clamps can be installed on each weld independently; i.e., any one, two, or three welds can be repaired with these repair clamps.
The proposed repair had been designed as an alternative to the requirements of ASME Boiler and Pressure Vellel Code (ASME),Section XI. The NRC staff has reviewed the proposed alternative repair. The enclosure is our SE which concludes that the proposed repair plan provides an acceptable level of quality and safety and is acceptable in accordance with 10 CFR 50.55a(a)(3)(i).
9905050283 990430 PDR ADOCK 05000220 p
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April 30, 1999 J. Mueller Ifyou have any questions regarding this matter, please contact Darl Hood by phone on (301) 415-3049 or by electronic mail at dsh@nrc.gov.
Sincerely, Original signed by:
Docket No. 50-220
Enclosure:
Safety Evaluation ccw/encl: See next page S. Singh Bajwa, Chief, Section 1
Project Directorate I
Division of I icensing Project Management Office of Nuclear Reactor Regulation DISTRIBUTION:
03nckeejlQ PUBLIC PDI-1 R/F J. Zwolinski/S. Black S. Bajwa S. Little D. Hood L. Lois R. Norsworthy (e-mail SE only to RCN)
OGC K. Manoly G. Hill W. Koo ACRS K. Kavanagh G. Shear J. Wermeil A. Blough, Rl R. Hermann J. Rajan '. Bateman DOCUMENT NAME:':>NMP1>RELA4701.WPD
'o receive a copy of this'document, indicate in the box: "C" = Copy without enclosures "E" = Co with enclosures "N"= No co 'e previous ccncurrence OFFICE PDI-1/PM NAME DHood:Icc DATE 04/ go/99 PDI-1/SC PDI-1/LA SLittle 04/S~/99 SBa wa 04/50/99 OFFICIAL RECORD COPY OGC
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April 30, 1999 J. Mueller Ifyou have any questions regarding this matter, please contact Darl Hood by phone on (301) 415-3049 or by electronic mail at dsh@nrc.gov.
Sincerely, Original signed by:
Docket No. 50-220
Enclosure:
Safety Evaluation ccw/encl: See next page S. Singh Bajwa, Chief, Section 1
Project Directorate I
Division of Licensing Project Management Office of Nuclear Reactor Regulation DISTRIBUTION:
Docket File PUBLIC PDI-1 R/F J. Zwolinski/S. Black S. Bajwa S. Little D. Hood L. Lois R. Norsworthy (e-mail SE only to RCN)
OGC K. Manoly G. Hill W. Koo ACRS K. Kavanagh G. Shear J. Wermeil A. Blough, Rl R. Hermann J. Rajan W, Bateman DOCUMENT NAME: G:iNMP1iRELA4701.WPD To receive a copy ofthis document, indicate in the box: "C" = Copy without enclosures "E" = Co with enclosures "N" = No co RB prevl ous concurrence OFFICE PDI-1/PM PDI-1/LA PDI-1/SC OGC
- NAME DATE DHood:Icc 04/a'(99 SBa'wa 04/50/99 S Little 04/S~/99 OFFICIAL RECORD COPY nc /3n/99
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J. Mueller Ifyou have any questions regarding this matter, please contact Darl Hood by phone on (301) 415-3049 or by electronic mail at dsh@nrc.gov.
Sincerely, S. Singh Bajwa, Chief, Section 1
Project Directorate I
Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-220
Enclosure:
Safety Evaluation cc w/encl: See next page
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Nine Mile Point Nuclear Station Unit No. 1 Regional Administrator, Region I
U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 126 Lycoming, NY 13093 Charles Donaldson, Esquire Assistant Attorney General New York Department of Law 120 Broadway New York, NY 10271 Mr. Paul D. Eddy State of New York Department of Public Service Power Division, System Operations 3 Empire State Plaza Albany, NY 12223 Mr. F. William Valentino, President New York State Energy, Research, and Development Authority Corporate Plaza West 286 Washington Avenue Extension Albany, NY 12203-6399 Mark J. Wetterhahn, Esquire, Winston & Strawn 1400 L Street, NW Washington, DC 20005-3502 Gary D. Wilson, Esquire Niagara Mohawk Power Corporation 300 Erie Boulevard West
- Syracuse, NY 13202
'upervisor Town of Scriba Route 8, Box 382 Oswego, NY 13126
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