ML20153B565

Forwards Safety Evaluation Accepting Proprietary Rept TR-105707, BWR Vessel & Internals Project,Safety Assessment of BWR Reactor Internals (BWRVIP-06) for Ranking Internal Components for Development of Insp & Flaw Evaluation

ML20153B565
Person / Time
Issue date:	09/15/1998
From:	Lainas G NRC (Affiliation Not Assigned)
To:	Terry C NIAGARA MOHAWK POWER CORP.
Shared Package
ML20153B570	List: ML20153B565 ML20153B581
References
TAC-M93926, NUDOCS 9809230178
Download: ML20153B565 (6)

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NUCLEAR REGULATORY COMMISSION

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September 15,1998 Carl Terry, BWRVIP Chalmian Niagara Mohawk Power Company Post Office Box 63 Lycoming, NY 13093

SUBJECT:

SAFETY EVALUATION OF THE BWR VESSEL AND INTERNALS PROJECT BWRVIP-06 REPORT (TAC NO. M93926)

Dear Mr. Terry,

By letter dated October 5,1995, as supplemented by letters dated December 20,1996, and June 16,1997, you submitted the Electric Power Research Institute (EPRI) Proprietary Report TR-105707, October 1995, "BWR Vessel and internals Project, Safety Assessment of BWR Reactor Intemals (BWRVIP-06)," for NRC staff review and approval. The BWRVIP-06 report provided a generic safety assessment of BWR/2 6 reactor internals to determine the short and long term actions required to assure safe operation with the potential for component cracking.

The assessment considered the reactor internal components function during normal, transient, seismic, and DBA conditions. The results of this assessment were intended to provide utilities with a generic reactor intemals management plan which could be tailored to meet the needs of the individual utilities. Additionally, this assessment was intended to provide the NRC with information needed to evaluate future cracking in BWR intemal components.

The NRC staff has reviewed the BWRVIP-06 report of operation with intergranular stress corrosion cracking (IGSCC) degraded internals and reviewed the results of the " Quantitative Safety Assessment of BWR Reactor Internals (BWRVIP 09)" report with respect to Draft Regulatory Guide (DG) 1061 (now Regulatory Guide (RG) 1.174) and finds, in the enclosed Safety Evaluation (SE), that: (1) if, in some cases, new procedures and/or changes to procedures are needed to detect potential f61lures, these items need to be considered to be near-term action items, to be implemented as soon as possible; and, (2) common mode failure of reactor intemals due to IGSCC was not evaluated in the BWRVIP 06 report and the BWRVIP did not provide an adequate basis for the assumption that only a single failure should be considered.

However, assuming single component failures, the BWRVIP-06 report adequately developed an I

overall prioritized list for determining which components required the immediate development of

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inspection and evaluation guidelines. Since the issuance of the BWRVIP 06 report, the industry has implemented effective inspection and repair programs to reduce the likelihood of component failure as a result of IGSCC. The results of these inspections were documented in letters dated n

April 18,1997, and March 31,1998. Although the consequences of multiple failures were not

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addressed in the report, inspections, evaluation and repairs (,f components to date, are considered sufficient to provide the staff with a high degree of confidence that multiple, undetected component failures are unlikely and to ensure component integrity for the components evaluated in the BWRVIP-06 report. In addition, this SER finds that the BWRVIP-06 report is acceptable for ranking internal components for the development of inspection and flaw evaluation guidelines.

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Carl Terry 2-The NRC's Office of Nuclear Regulatory Research (RES) is presently performing confirmatory research into the possible consequences of multiple, cascading component failures. Should the results from this confirmatory research program identify any significant issues, they will be addressed separately with you.

Please contact C. E. (Gene) Carpenter, Jr., of my staff at (301) 415-2169 if you have any further questions regarding this subject.

Sincerely, (Mis 9patby Gus C. Lainas, Acting Director Division of Engineering Office of Nuclear Reactor Regulation

Enclosure:

As stated cc: See next page Distribution:

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1 Carl Terry Should the results from the confirmatory research program on synergistic effects identify any significant issues, they will be addressed separately.

Please contact C. E. (Gene) Carpenter, Jr., of my staff at (301) 415-2169 if you have any further questions regarding this subject.

Sincerely, Gus C. Lainas, Acting Director Division of Engineering Office of Nuclear Reactor Regulation

Enclosure:

As stated cc: See next page Distribution:

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Please contact C. E. (Gene) Carpenter, Jr., of my staff at (301) 415-2169 if you have any further l

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Sincerely, Gus C. Lainas, Acting Director Division of Engineering Office of Nuclear Reactor Ragulation

Enclosure:

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4 George Jones, Executive Chairman Dana Covill, Technical Chairman 4

BWRVIP AssessmentTask' BWRVIP Assessment Task

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Pennsylvania Power & Light GPU Nuclear

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,i 1 Upper Pond Road Two North Ninth Street Parsippany,NJ 07054 Allentown, PA 18101 4

Joa Hagan, Executive Chairman Carl Larsen, Technical Chairman BWRVIP inspection Task BWRVIP inspection Task Entergy Yankee Atomic P. O. Box 756 580 Main Street Waterloo Road Bolton,MA 01740 Port Gibson, MS 39150 1

Paul Bemis, Executive Chairman Vaughn Wagoner, Technical Chairman BWRVIP Intagration Task BWRVIP Integration Task Washington Public Power Supply System Carolina Power & Light Company P. O. Box 968.

One Hannover Square 9C1 North Power Plent Loop P.O. Box 1551 Richland, WA 95352 0968 Raleigh, NC 27612 Lewis Sumner,5xecuilve Chairrnan John Wilson, Technical Chairman BWRVIP Mitigation Task BWRVIP Mitigation Task Southem Nuclear Operating Co.

Clinton Power Station, M/C T-31C 40 invemess Center Parkway P.O. Box 678 Birmingham, AL 35201 Clinton,IL 61727 1

- John Blomgren, Executive Chairman Bruce McLeod, Technical Chairman BWRVIP RepairTask BWRVIP Repair Task Commonwealth Edison Co.

Southem Nuclear Operating Co.

1400 Opus Place, Suite 600 Post Office Box 1295 Downers Grove, IL 60515-5701 40 invemess Center Parkway Birmingham, AL 35201 Bili Campbell, BWRVIP Vice Chaliman Warren Bilanin, EPRI BWRVIP Carolina Power & Light Integration Manager P. O. Box 1551 Joe Gilman, EPRI BWRVIP Raleigh, NC 27612 Mitigation Manager Ken Wolfe, EPRI BWRVIP Robert Carter, EPRI BWRVIP Repair Manager Assessment Manager Electric Power Research Institute Greg Selby, EPRI BWRVIP P. O. Box 10412 Inspection Manager 3412 Hillview Ave.

EPRI NDE Center Palo Alto,CA 94303 P. O. Box 217097 1300 W. T. Harris Blvd.

Charlotte, NC 28221

l Carl Terry 2-l' i

j The NRC's Office of Nuclear Fiegulatory Research (RES) is presently performing confirmatory i

research into the possible consequences of multiple, cascading component failures. Should the results from this confirmatory research program identify any significant issues, they will be addressed separately with you.

Please contact C. E. (Gene) Carpenter, Jr., of my staff at (301) 415-2169 if you have any further questions regarding this subject.

Sincerely, Gus C. Lainas, Acting Director Division of Engineering Office of Nuclear Reactor Regulation

Enclosure:

As stated cc: See next page l

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