ML061780168
| ML061780168 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 07/05/2006 |
| From: | Shawn Campbell Plant Licensing Branch III-2 |
| To: | Bezilla M FirstEnergy Nuclear Operating Co |
| Campbell S, NRC/NRR/DORL, 415-1486 | |
| References | |
| GL-04-001, TAC MC4816 | |
| Download: ML061780168 (6) | |
Text
July 5, 2006 Mr. Mark A. Bezilla Vice President-Nuclear, Davis-Besse FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station 5501 North State Route 2 Oak Harbor, OH 43449-97960
SUBJECT:
DAVIS-BESSE NUCLEAR POWER STATION, UNIT 1 - RESPONSE TO GENERIC LETTER 2004-01, REQUIREMENTS FOR STEAM GENERATOR TUBE INSPECTIONS (TAC NO. MC4816)
Dear Mr. Bezilla:
On August 30, 2004, the Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2004-01, Requirements For Steam Generator Tube Inspections. The purpose of GL 2004-01 was to obtain information that would enable the NRC staff to determine whether licensees steam generator (SG) tube inspection programs comply with the existing tube inspection requirements (the plant technical specifications in conjunction with Appendix B to Title 10 of the Code of Federal Regulations Part 50).
By letter dated October 29, 2004, as supplemented by letter dated July 26, 2005, you responded to GL 2004-01 for Davis-Besse Nuclear Power Station, Unit 1 (DBNPS). The NRC staffs review of your response to the GL did not identify any concerns with the inspection practices employed at DBNPS. The NRC staff, therefore, concludes that your SG tube inspection practices are in compliance with the existing tube inspection requirements.
The NRC staffs evaluation is enclosed. If you have any questions regarding this matter, please contact me at (301) 415-1486.
Sincerely,
/RA/
Stephen J. Campbell, Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-346
Enclosure:
As stated cc: See next page
ML061780168 OFFICE LPL3-2/PM LPL3-2/LA CSGB/BC LPL3-2/BC NAME SCampbell:mw DClarke AHiser (TBloomer for)
KJabbour for DCollins DATE 7/ 5/06 7/3/ 06 6/27/ 06 7 /5/ 06
ENCLOSURE EVALUATION OF THE RESPONSE TO GL 2004-01 FIRSTENERGY NUCLEAR OPERATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION, UNIT 1 DOCKET NO. 50-346 On August 30, 2004, the Nuclear Regulatory Comission (NRC) issued Generic Letter (GL) 2004-01, Requirements For Steam Generator Tube Inspections, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML042370766). The purpose of GL 2004-01 was to obtain information that would enable the NRC staff to determine whether licensees steam generator tube inspection programs comply with the existing tube inspection requirements (the plant technical specifications) in conjunction with Appendix B to Title 10 of the Code of Federal Regulations Part 50.
By letter dated October 29, 2004 (ADAMS Accession No. ML043070391), as supplemented by letter dated July 26, 2005 (ADAMS Accession No. ML052090243), FirstEnergy Nuclear Operating Company (FirstEnergy), the licensee for Davis-Besse Nuclear Power Station, Unit 1 submitted a response to GL 2004-01. The NRC staff has concluded that FirstEnergy steam generator tube inspection practices are in compliance with the existing tube inspection requirements; however, the NRC staff has the following observations regarding the tube inspection practices in the lower tubesheet (LTS) region.
A portion of the LTS is referred to as the sludge pile or kidney region. Although the NRC staff could not identify a uniform, quantitative definition of this region in terms of the radial extent (minimum sludge height and/or dent voltage) or axial extent above and below the top of the LTS, it is generally defined by the four Babcock and Wilcox (B&W) units with Alloy 600 tubing as the area bounded by dents and sludge at the LTS secondary face. The definition does not include the tube ends, the roll expanded region, or the roll transition which are addressed by separate inspections.
Based on industry operating experience (from the four currently operating B&W units with Alloy 600 tubing), the sludge pile or kidney region is susceptible to intergranular attack (IGA) and stress corrosion cracking (SCC). IGA and axially-oriented SCC have been detected both above and below the top of the LTS at non-dented locations. In addition, IGA and circumferentially-oriented SCC have been detected at dented locations in the sludge pile or kidney region.
With respect to dented locations in the LTS region, the NRC staff notes that FirstEnergy performed separate inspections of these locations on a sampling basis with a rotating probe (i.e., FirstEnergy specified separate inspections for the dented locations within the LTS region).
The NRC staff concludes that the examination of the dented locations in the LTS region are in compliance with the existing tube inspection requirements.
The NRC staff recognizes that FirstEnergy concluded (based on site-specific qualification) that the bobbin techniques may be used for detecting SCC and IGA in the sludge pile or kidney region. Based on the information FirstEnergy provided in its submittals regarding the site-specific inspection qualification, the NRC staff could not conclude for non-dented locations that the bobbin coil technique is effective at finding the forms of degradation that could occur within the kidney or sludge pile region. The NRC staff understands that FirstEnergy recognizes the potential for the bobbin coil site-specific validation may change over time. As a result, FirstEnergy performed additional +PointTM probe examinations in this region that meet industry sampling requirements for a non-active degradation mechanism. Historically, these rotating probe examinations have indicated that the bobbin coil has not missed any degradation at the non-dented locations in this region of the tube bundle. Based on the rotating probe inspections and the results of these inspections, the NRC staff concludes that FirstEnergys inspection practices at the non-dented locations within the LTS region are in compliance with the existing tube inspection requirements.
Principal Contributors: P. Klein M. Yoder Date: July 5, 2006
Davis-Besse Nuclear Power Station, Unit 1 cc:
Manager - Regulatory Affairs FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station 5501 North State - Route 2 Oak Harbor, OH 43449-9760 Director, Ohio Department of Commerce Division of Industrial Compliance Bureau of Operations & Maintenance 6606 Tussing Road P.O. Box 4009 Reynoldsburg, OH 43068-9009 Regional Administrator U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, IL 60523-4351 Resident Inspector U.S. Nuclear Regulatory Commission 5503 North State Route 2 Oak Harbor, OH 43449-9760 Barry Allen, Plant Manager FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station 5501 North State - Route 2 Oak Harbor, OH 43449-9760 Dennis Clum Radiological Assistance Section Supervisor Bureau of Radiation Protection Ohio Department of Health P.O. Box 118 Columbus, OH 43266-0118 Carol OClaire, Chief, Radiological Branch Ohio Emergency Management Agency 2855 West Dublin Granville Road Columbus, OH 43235-2206 Zack A. Clayton DERR Ohio Environmental Protection Agency P.O. Box 1049 Columbus, OH 43266-0149 State of Ohio Public Utilities Commission 180 East Broad Street Columbus, OH 43266-0573 Attorney General Office of Attorney General 30 East Broad Street Columbus, OH 43216 President, Board of County Commissioners of Ottawa County Port Clinton, OH 43252 President, Board of County Commissioners of Lucas County One Government Center, Suite 800 Toledo, OH 43604-6506 The Honorable Dennis J. Kucinich United States House of Representatives Washington, D.C. 20515 The Honorable Dennis J. Kucinich United States House of Representatives 14400 Detroit Avenue Lakewood, OH 44107 Gary R. Leidich President and Chief Nuclear Officer FirstEnergy Nuclear Operating Company Mail Stop A-GO-19 76 South Main Street Akron, OH 44308 Joseph J. Hagan Senior Vice President of Operations and Chief Operating Officer FirstEnergy Nuclear Operating Company Mail Stop A-GO-14 76 South Main Street Akron, OH 44308 David W. Jenkins, Attorney FirstEnergy Corporation Mail Stop A-GO-18 76 South Main Street Akron, OH 44308
Davis-Besse Nuclear Power Station, Unit 1 cc:
Danny L. Pace Senior Vice President, Fleet Engineering FirstEnergy Nuclear Operating Company Mail Stop A-GO-14 76 South Main Street Akron, OH 44308 Manager, Fleet Licensing FirstEnergy Nuclear Operating Company Mail Stop A-GHE-107 395 Ghent Road Akron, OH 44333 Manager, Site Regulatory Compliance FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station Mail Stop A-DB-3065 5501 North State Route 2 Oak Harbor, OH 43449-9760 Jeannie M. Rinckel Vice President, Fleet Oversight FirstEnergy Nuclear Operating Company Mail Stop A-GO-14 76 South Main Street Akron, OH 44308