ML023360467
| ML023360467 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/26/2002 |
| From: | Dave Solorio NRC/NRR/DRIP/RLEP |
| To: | Gallagher M Exelon Corp |
| Solorio, D L, NRR/DRIP/RLEP, 415-1973 | |
| References | |
| Download: ML023360467 (8) | |
Text
November 26, 2002 Mr. Michael P. Gallagher Director-Licensing Exelon Corporation 200 Exelon Way Kennett Square, PA 19348
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RELATED TO OPEN ITEM 4.5.2-1 FROM LICENSE RENEWAL SAFETY EVALUATION REPORT WITH OPEN AND CONFIRMATORY ITEMS FOR THE PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3
Dear Mr. Gallagher:
By letter dated September 13, 2002, the NRC staff (the staff) forwarded to you the Safety Evaluation Report With Open and Confirmatory Items Related to the License Renewal of the Peach Bottom Atomic Power Station, Units 2 and 3, hereafter referred to as the SER (ADAMS Accession No. ML022590468). This SER reflected the status of the staffs review of Exelons license renewal application, requests for additional information (RAIs) and clarification, and Exelons responses to the staffs RAIs through July 30, 2001, unless otherwise noted.
As the staff has worked with your staff to resolve the open and confirmatory items, we have reached a point with respect to Open Item 4.5.2-1 where additional information, contained in, is required beyond the draft information provided by Exelon in Enclosure 2. The nature of this information was also discussed in a teleconference with Exelon staff that occurred on November 14, 2002.
Sincerely,
/RA/
David L. Solorio License Renewal Section License Renewal and Environmental Impacts Program Division of Regulatory Improvement Programs Office of Nuclear Reactor Regulation Docket Nos.: 50-277 and 50-278
Enclosures:
As stated cc w/encls: See next page
Mr. Michael P. Gallagher Director-Licensing Exelon Corporation 200 Exelon Way Kennett Square, PA 19348
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RELATED TO OPEN ITEM 4.5.2-1 FROM LICENSE RENEWAL SAFETY EVALUATION REPORT WITH OPEN AND CONFIRMATORY ITEMS FOR THE PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3
Dear Mr. Gallagher:
By letter dated September 13, 2002, the NRC staff (the staff) forwarded to you the Safety Evaluation Report With Open and Confirmatory Items Related to the License Renewal of the Peach Bottom Atomic Power Station, Units 2 and 3, hereafter referred to as the SER (ADAMS Accession No. ML022590468). This SER reflected the status of the staffs review of Exelons license renewal application, requests for additional information (RAIs) and clarification, and Exelons responses to the staffs RAIs through July 30, 2001, unless otherwise noted.
As the staff has worked with your staff to resolve the open and confirmatory items, we have reached a point with respect to Open Item 4.5.2-1 where additional information, contained in, is required beyond the draft information provided by Exelon in Enclosure 2. The nature of this information was also discussed in a teleconference with Exelon staff that occurred on November 14, 2002.
Sincerely,
/RA/
David L. Solorio License Renewal Section License Renewal and Environmental Impacts Program Division of Regulatory Improvement Programs Office of Nuclear Reactor Regulation Docket Nos.: 50-277 and 50-278
Enclosures:
As stated cc w/encls: See next page DISTRIBUTION:
See next page Document Name: C:\\ORPCheckout\\FileNET\\ML023360467.wpd OFFICE PM:RLEP:DRIP LA:RLEP:DRIP SC:RLEP:DRIP BC:EMCB:DE BC:RLEP:DRIP NAME DSolorio HBerilla SLee BBateman PTKuo DATE 11/22/02 11/22/02 11/23/02 11/25/02 11/26/02 OFFICIAL RECORD COPY
DISTRIBUTION: Letter to Michael P. Gallagher, Dated: November 26, 2002 Package: ML023330195 HARD COPY RLEP RF D. Solorio R. Hoefling E-MAIL:
PUBLIC J. Johnson W. Borchardt D. Matthews F. Gillespie RidsNrrDe R. Barrett J. Zwolinski E. Imbro G. Bagchi K. Manoly W. Bateman J. Calvo C. Holden P. Shemanski H. Nieh G. Holahan H. Walker S. Black B. Boger D. Thatcher G. Galletti C. Li J. Moore R. Weisman M. Mayfield A. Murphy W. McDowell S. Smith R. Assa C. Munson RLEP Staff J. Boska M. Modes D. Lew B. Elliot S. Coffin B. Bateman G. Hatchett
Peach Bottom Atomic Power Station, Units 2 and 3 cc:
Vice President, General Counsel and Secretary Exelon Generation Company, LLC 300 Exelon Way Kennett Square, PA 19348 Site Vice President Peach Bottom Atomic Power Station Exelon Generation Company, LLC 1848 Lay Road Delta, PA 17314 Plant Manager Peach Bottom Atomic Power Station Exelon Generation Company, LLC 1848 Lay Road Delta, PA 17314 Regulatory Assurance Manager Peach Bottom Atomic Power Station Exelon Generation Company, LLC 1848 Lay Road Delta, PA 17314 Resident Inspector U.S. Nuclear Regulatory Commission Peach Bottom Atomic Power Station P.O. Box 399 Delta, PA 17314 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. Roland Fletcher Department of Environment Radiological Health Program 1800 Washington Blvd.
Baltimore, MD 21230 Correspondence Control Desk Exelon Generation Company, LLC 200 Exelon Way, KSA 1-N-1 Kennett Square, PA 19348 Rich Janati, Chief Division of Nuclear Safety Bureau of Radiation Protection Department of Environmental Protection Rachel Carson State Office Building P.O. Box 8469 Harrisburg, PA 17105-8469 Board of Supervisors Peach Bottom Township 545 Broad Street Ext.
Delta, PA 17314-9203 Mr. Richard McLean Power Plant and Environmental Review Division Department of Natural Resources B-3, Tawes State Office Building Annapolis, MD 21401 Dr. Judith Johnsrud National Energy Committee Sierra Club 433 Orlando Avenue State College, PA 16803 Manager-Financial Control & Co-Owner Affairs Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, NJ 08038-0236 Manager Licensing-Limerick and Peach Bottom Exelon Generation Company, LLC Nuclear Group Headquarters Correspondence Control P.O. Box 160 Kennett Square, PA 19348 Mr. Alan P. Nelson Nuclear Energy Institute 1776 I Street, N.W., Suite 400 Washington, DC 20006-3708 Peach Bottom Atomic Power Station, Units 2 and 3 cc:
Director - Licensing Mid-Atlantic Regional Operating Group Exelon Generation Company, LLC Nuclear Group Headquarters Correspondence Control P.O. Box 160 Kennett Square, PA 19348 Vice President-Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Senior Vice President Mid-Atlantic Regional Operating Group Exelon Generation Company, LLC 200 Exelon Way, KSA 3-N Kennett Square, PA 19348 Senior Vice President, Nuclear Services Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Vice President, Mid-Atlantic Operations Support Exelon Generation Company, LLC 200 Exelon Way, KSA 3-N Kennett Square, PA 19348 Manager License Renewal Exelon Generation Company, LLC 200 Exelon Way Kennett Square, PA 19348 Mr. Oliver D. Kingsley, President Exelon Nuclear Exelon Generation Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348 Public Service Commission of Maryland Engineering Division Chief Engineer 6 St. Paul Center Baltimore, MD 21202-6806 Chief Operating Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 BWRVIP-26, BWR Top Guide Inspection and Flaw Evaluation Guidelines, states that the threshold fluence beyond which the components will be significantly affected is 5 x 1020 n/cm2 (neutrons per centimeter squared). At neutron fluences above this threshold, components would be susceptible to irradiation-assisted stress corrosion cracking (IASCC). Appendix C to BWRVIP-26 states that the generic fluence on the top guide for 60 years is 6 x 1021 n/cm2, which exceeds the 5 x 1020 n/cm2 damage threshold.
The applicant further stated that the location on the top guide that will see this high fluence is the grid beam. This is location 1, as identified in BWRVIP-26, Table 3-2, Matrix of Inspection Options. In their evaluation of the top guide assembly, including the grid beam, General Electric (GE) assumed a lower allowable stress value, acknowledging the high fluence value at this location. The conclusion from this analysis was no inspection was necessary because there was no safety consequence of single failure at this location.
BWRVIP-26, Section 6.3, Core Configuration Distortion, indicates multiple ruptures of adjacent beam segments could lead to displacements of fuel assemblies at the top guide elevation on the order of five inches, and could inhibit the insertion of control rods during seismic events.
The staff is concerned that multiple failures of top guide beams are possible when the threshold fluence for IASCC is exceeded. According to Topical Report, BWRVIP-26A: BWR Vessel and Internals Project, BWR Top Guide Inspection and Flaw Evaluation Guidelines, February 2002, multiple cracks have been observed in top guide beams at Oyster Creek. In addition, baffle former bolts on PWRs that exceeded the threshold fluence have had multiple failures of baffle former bolts. The staff agrees with the BWRVIP-26 conclusion for top guide beams that no inspection is required when a single failure is postulated. However, when the neutron fluence for the top guide beam exceeds the IASCC damage threshold, the staff believes that multiple failures from IASCC are possible and an inspection program is necessary to ensure that multiple failures do not result in the loss of the ability of control rods to be inserted. In order to ensure that this issue was addressed during the license renewal term, the staff identified this as a TLAA in its SER, which is documented in a December 7, 2000, letter to C. Terry. Section 3.5 of the staffs SER indicates that accumulated neutron fluence is a TLAA issue and must be identified and evaluated by individual applicants considering license renewal.
With this background, how have you considered the impact of multiple cracks resulting from IASCC on the ability to insert control rods during design basis events? If multiple cracks resulting from IASCC could impact the ability to insert control rods during design basis events, how will this aging effect be managed during the license renewal period?