ML20209F114
| ML20209F114 | |
| Person / Time | |
|---|---|
| Issue date: | 07/08/1999 |
| From: | Strosnider J NRC (Affiliation Not Assigned) |
| To: | Terry C AFFILIATION NOT ASSIGNED, NIAGARA MOHAWK POWER CORP. |
| Shared Package | |
| ML20209F119 | List: |
| References | |
| TAC-MA5057, NUDOCS 9907150228 | |
| Download: ML20209F114 (3) | |
Text
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2 WASHINGTON, D.C. 2066H001
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July 8, 1999 Carl Terry, BWRVIP Chairman Niagara Mohawk Power Company Post Office Box 63 Lycoming, NY 13093
SUBJECT:
SAFETY EVALUATION OF THE "BWRVIP VESSEL AND INTERNALS PROJECT, EVALUATION OF STRESS CORROSION CRACK GROWTH IN LOW ALLOY STEEL VESSEL MATERIALS IN THE BWR ENVIRONMENT (BWRVIP-60)," EPRI REPORT TR-108709, MARCH 1999 (TAC NO. MA5057)
Dear Mr. Terry,
The NRC staff has completed its review of the Electric Power Research Institute (EPRI) proprietary report TR-108709, "BWR Vessel and Internals Project, Evaluation of Stress Corrosion Cracking in Low Alloy Steel Vessel Materials in the BWR Environment (BWRVIP-60)," March 1999 The BWRVIP-60 report was submitted by letter dated March 30,1999.
The BWRVIP-60 report provides a formal methodology for the determination of stress corrosion cracking (SCC) in low alloy steel (LAS) reactor pressure vessels (RPV) and nozzles in a boi!!ng water reactor (BWR) environment. In partkular, an evaluation is presented to assess the long-term potential susceptibility of the austenitic stainless steel cladding and the LAS base metal to SCC during normal water chemistry (NWC) or hydrogen water chemistry (HWC) plant operation. The allowable circumferential and axial flaw sizes were also calculated based on the guidelines provided in the American Society of Mechanical Engineers (ASME) Boiler and 4
Pressure Vessel Code Section XI, " Rules for Inservice Inspection of Nuclear Power Plant Components," Article IWB-3600, " Analytical Evaluation of Flaws."
The NRC staff has reviewed the BWRVIP-60 report and found, in the enclosed safety
//
l evaluation (SE), that the guidance of the BWRVIP-60 report is acceptable for the assessment
/
of stress corrosion crack growth in BWR LAS pressure vessels and nozzles. The results of the licensee's methodology are acceptable because established fracture mechanic models, h3 integrating existing crack growth rate data and a mechanistic understanding of SCC, were used to determine the through-wall K distributions for the cladding, attachment arid vessel welds. In addition, ASME Section XI Code criteria were followed in the calculation of the allowable flaw sizes. Therefore, the staff has concluded that the procedures in the BWRVIP-60 report will provide an acceptable approach in appraising crack growth of the LAS RPV components addressed.
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Carl Terry l l
Please contact C. E. (Gene) Carpenter, Jr., of my staff at (301) 415-2169 if you have any i
further questions regarding this subject.
Sincerely a.
40+t.4 24
- Jack R. Strosnider, Director Division of Engineering Office of Nuclear Reactor Regulation
Enclosure:
As stated i
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Karl W. Singer, Executive Chair Steve Lewis, Technical Chairman BWRVIP Assessment Task BWRVIP Assessment Task Tennessee Valley Authority Entergy
, PO Box 2000 P O. Box 756 l
Decaltur, AL 35602-2000 Waterloo Road Port Gibson, MS 39150 Bill Eaton, Executive Chair inspection Committee Carl Larsen, Technical Chairman Entergy Operations, Inc.
BWRVIP Inspection Task PO Box 756,' Waterloo Rd Yankee Atomic Port Gibson, MS 39150-0756 -
580 Main Street Bolton, MA 01740 H. Lewis Sumner, Executive Chairman BWRVIP Mitigation Task John Wilson, Technical Chairman Southern Nuclear Operating Co.
BWRVIP Mitigation Task M/S BIN B051, PO Box 1295 Clinton Power Station, M/C T-31C 40 inverness Center Parkway P.O. Box 678 Birmingham, AL 35201 Clinton,IL 61727 Harry P. Salmon, Executive Chairman Vaughn Wagoner, Technical Chairman BWRVIP Integration Task BWRVIP Integration Task New York Power Authority Carolina Power & Light Company 123 Main St., M/S 11 D One Hannover Square 9C1 White Plains, NY 10601-3104 P.O. Box 1551 Raleigh, NC 27612 George T. Jones, Executive Chair BWRVIP Repair Task Bruce McLeod, Technical Chairman Pennsylvania Power & Light, Inc.
BWRVIP Repair Task M/S GEN A 61 Southern Nuclear Operating Co.
2 N 9* Street Post Office Box 1295 Allentown, PA 18101-1139 40 inverness Center Parkway Birmingham, AL 35201 Robert Carter, EPRI BWRVIP Assessment Manager Tom Mulford, EPRI BWRVIP EPRI NDE Center integration Manager P. O. Box 217097 Raj Pathania, EPRI BWRVIP 1300 W. T. Harris Blvd.
Mitigation Manager Charlotte, NC 28221 Ken Wolfe, EPRI BWRVIP Repair Manager Greg Selby, EPRI BWRVIP Electric Power Research Institute inspection Manager P. O. Box 10412 EPRI NDE Center 3412 Hillview Ave.
P. O. Box 217097 Palo Alto, CA 94303 1300 W. T. Harris Blvd.
Charlotte, NC 28221 James P. Pelletier, BWRVIP Liaison to EPRI Nuclear Power Council
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Joe Hagan, BWRVIP Vice Chairman Nebraska Public Power District PEPCO Energy Co.
1200 Prospect Avenue MC 62C-3 PO Box 98 965 Chesterbrook Blvd Brownville, NE 68321-0098 Wayne, PA 19807-5691 J