ML061080422
| ML061080422 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 05/04/2006 |
| From: | Mahesh Chawla Plant Licensing Branch III-2 |
| To: | Crane C Exelon Generation Co |
| Mahesh Chawla, LPL3-1, 415-8371 | |
| References | |
| TAC MC7776 | |
| Download: ML061080422 (6) | |
Text
May 4, 2006 Mr. Christopher M. Crane, President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BYRON STATION UNIT 1 - REVIEW OF THE SPRING 2005 STEAM GENERATOR TUBE INSPECTION REPORTS (TAC NO. MC7776)
Dear Mr. Crane:
By letters to the Nuclear Regulatory Commission dated March 28 and June 3, 2005, and February 13, 2006, you submitted information related to the steam generator tube inspections for the spring 2005 refueling outage at the Byron Station (Byron), Unit 1, in accordance with the plants technical specifications (TS).
The NRC staff has completed its review of these reports and concludes that you have provided the information required by the Byron TSs, and that no additional follow-up is required at this time.
Sincerely,
/RA/
Mahesh Chawla, Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-454
Enclosure:
Evaluation of Steam Generator Tube Inspection Reports cc w/encl: See next page
Mr. Christopher M. Crane, President May 4, 2006 and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BYRON STATION UNIT 1 - REVIEW OF THE SPRING 2005 STEAM GENERATOR TUBE INSPECTION REPORTS (TAC NO. MC7776)
Dear Mr. Crane:
By letters to the Nuclear Regulatory Commission dated March 28 and June 3, 2005, and February 13, 2006, you submitted information related to the steam generator tube inspections for the spring 2005 refueling outage at the Byron Station (Byron), Unit 1, in accordance with the plants technical specifications (TS).
The NRC staff has completed its review of these reports and concludes that you have provided the information required by the Byron TSs, and that no additional follow-up is required at this time.
Sincerely,
/RA/
Mahesh Chawla, Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-454
Enclosure:
Evaluation of Steam Generator Tube Inspection Reports cc w/encl: See next page DISTRIBUTION:
PUBLIC LPLIII-2 r/f RidsNRRPMMChawla RidsOgcRp DHills, RIII KKarwoski RidsNrrDorlLplf RidsAcrsAcnwMailCenter EMurphy RidsNrrLADClarke RSkokowski, RIII YDiaz RKuntz ADAMS Accession Number: ML061080422 OFFICE PM:LPL3-2 LPL3-2 LA:LPL3-2 BC:LPL3-2 NAME MChawla TWengert DClarke DCollins DATE 4/27/06 5/1/06 5/1/06 5/4/06 OFFICIAL RECORD COPY
ENCLOSURE OFFICE OF NUCLEAR REACTOR REGULATION EVALUATION OF STEAM GENERATOR INSPECTION REPORTS FOR SPRING 2005 REFUELING OUTAGE BYRON STATION, UNIT 1 DOCKET NO. STN 50-454
1.0 INTRODUCTION
By letters to the Nuclear Regulatory Commission (NRC) dated March 28 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML050950421),
June 3, 2005 (ADAMS Accession Number ML051600185), and February 13, 2006 (ADAMS Accession No. ML060440101), Exelon Generation Company (the licensee) submitted information related to the steam generator (SG) tube inspections for the spring 2005 refueling outage at Byron Station (Byron), Unit 1.
2.0 BACKGROUND
Byron, Unit 1 has four Babcock & Wilcox replacement SGs. Each SG contains 6,633 thermally-treated Inconel-690 U-tubes. Each tube has a nominal outside diameter of 0.6875 inch and a nominal wall thickness of 0.040 inch. The tubes were hydraulically expanded at both ends for the full length of the tubesheet and are supported by a number of stainless steel lattice grid structures and fan bars.
3.0 RESULTS OF SPRING 2005 INSPECTION The licensee provided the scope, extent, methods and results of their SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions (i.e., tube plugging) taken in response to the inspection findings.
Of particular note is that 46 indications of fan bar wear, none of which exceeded the plugging limit, were identified during the 100 percent full-length bobbin coil inspections of all four SGs during the 2005 outage. During the last SG tube inspections in 2002, in which approximately 50 percent of the tubes were inspected, only 12 indications of fan bar wear were identified.
The licensee evaluated the increase in the number of wear indications and concluded that there was not a significant increase in the wear initiation rate; rather it was a result of the increase in the sample size and the amount of time it takes for a flaw to grow to the threshold of detection.
The licensee also concluded that the 5-percent power uprate in 2001 did not increase the susceptibility of the SG tubes to wear.
4.0 CONCLUSION
S Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by the Byron, Unit 1 technical specifications. In addition, the NRC staff concludes that there are no technical issues that warrant follow-up action at this time since the inspections appear to be consistent with the objective of detecting potential tube degradation and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units.
Principal Contributor: Y. Diaz-Castillo Date: May 4, 2006
Byron Station Units 1 and 2 cc:
Regional Administrator, Region III U.S. Nuclear Regulatory Commission Suite 210 2443 Warrenville Road Lisle, IL 60532-4351 Illinois Emergency Management Agency Division of Disaster Assistance &
Preparedness 110 East Adams Street Springfield, IL 62701-1109 Document Control Desk - Licensing Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Mr. Dwain W. Alexander, Project Manager Westinghouse Electric Company Post Office Box 355 Pittsburgh, PA 15230 Joseph Gallo Gallo & Ross 1025 Connecticut Ave., NW, Suite 1014 Washington, DC 20036 Howard A. Learner Environmental Law and Policy Center of the Midwest 35 East Wacker Drive Suite 1300 Chicago, IL 60601-2110 U.S. Nuclear Regulatory Commission Byron Resident Inspectors Office 4448 North German Church Road Byron, IL 61010-9750 Ms. Lorraine Creek RR 1, Box 182 Manteno, IL 60950 Chairman, Ogle County Board Post Office Box 357 Oregon, IL 61061 Mrs. Phillip B. Johnson 1907 Stratford Lane Rockford, IL 61107 Attorney General 500 S. Second Street Springfield, IL 62706 Byron Station Plant Manager Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Site Vice President - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Senior Vice President of Operations Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Chairman Will County Board of Supervisors 302 North Chicago Street Will County Board Courthouse Joliet, Illinois 60434
Byron Station Units 1 and 2 Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Regulatory Assurance Manager - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Assistant General Counsel Exelon Generation Company, LLC 200 Exelon Way Kennett Square, PA 19348 Vice President - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Manager Licensing - Braidwood and Byron Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555