ML070590534
| ML070590534 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 03/19/2007 |
| From: | Robert Kuntz NRC/NRR/ADRO/DORL/LPLIII-2 |
| To: | Crane C Exelon Generation Co |
| Kuntz, Robert , NRR/DLPM, 415-3733 | |
| References | |
| TAC MD1199 | |
| Download: ML070590534 (6) | |
Text
March 19, 2007 Mr. Christopher M. Crane President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BYRON STATION, UNIT NO. 2 - REVIEW OF THE FALL 2005 STEAM GENERATOR TUBE INSPECTION REPORTS (TAC NO. MD1199)
Dear Mr. Crane:
By letters to the Nuclear Regulatory Commission (NRC), dated January 3, and September 8, 2006, and January 16, 2007, you submitted information related to the steam generator tube inspections for the fall 2005, refueling outage at the Byron Station, Unit No. 2 (Byron), 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 TS, and that no additional follow-up is required at this time.
Sincerely,
/RA/
Robert F. Kuntz, Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-455
Enclosure:
Evaluation of Steam Generator Tube Inspection Reports cc w/encl: See next page
Mr. Christopher M. Crane March 19, 2007 President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BYRON STATION, UNIT NO. 2 REVIEW OF THE FALL 2005 STEAM GENERATOR TUBE INSPECTION REPORTS (TAC NO. MD1199)
Dear Mr. Crane:
By letters to the Nuclear Regulatory Commission (NRC), dated January 3, and September 8, 2006, and January 16, 2007, you submitted information related to the steam generator tube inspections for the fall 2005, refueling outage at the Byron Station, Unit No. 2 (Byron), 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 TS, and that no additional follow-up is required at this time.
Sincerely,
/RA/
Robert F. Kuntz, Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-455
Enclosure:
Evaluation of Steam Generator Tube Inspection Reports cc w/encl: See next page DISTRIBUTION:
PUBLIC LPL3-2 R/F LMiller, NRR RidsOgcRp DHills, Region III KKarwoski, NRR RidsNrrDorlLpl3-2 RidsAcrsAcnwMailCenter RidsNrrPMRKuntz RidsNrrLAEWhitt RSkokowski, Region III ADAMS Accession Number: ML070590534 NRR-106 OFFICE LPL3-2/PM LPL3-2/LA LPL3-2/BC NAME RKuntz:mw EWhitt RGibbs DATE 3/16/2007 3/15/2007 3/19/2007 OFFICIAL RECORD COPY
Byron Station, Units 1 and 2 cc:
Regional Administrator, Region III U.S. Nuclear Regulatory Commission 2443 Warrenville Road, Suite 210 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 Corporation P.O. Box 355 Pittsburgh, PA 15230 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 P.O. Box 357 Oregon, IL 61061 Mrs. Phillip B. Johnson 1907 Stratford Lane Rockford, IL 61107 Attorney General 500 S. Second Street Springfield, IL 62701 Plant Manager - Byron Station Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Site Vice President - Byron Station Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Senior Vice President - Operations Support Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Chairman Will County Board of Supervisors Will County Board Courthouse Joliet, IL 60434 Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Manager Regulatory Assurance - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Associate General Counsel Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Vice President - Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
Byron Station, Units 1 and 2 cc:
Manager Licensing - Braidwood, Byron and LaSalle Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Senior Vice President - Midwest Operations Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Mr. Barry Quigley 3512 Louisiana Rockford, IL 61108
Enclosure OFFICE OF NUCLEAR REACTOR REGULATION EVALUATION OF STEAM GENERATOR INSPECTION REPORTS FOR THE TWELFTH REFUELING OUTAGE BYRON STATION, UNIT NO. 2 DOCKET NO. STN 50-455 By letter to the Nuclear Regulatory Commission (NRC) dated October 17, 2005 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML052920168), Exelon Generation Company, LLC (the licensee) submitted the steam generator (SG) tube plugging report in accordance with Technical Specification (TS) Section 5.6.9. By letter dated January 3, 2006 (ADAMS Accession No. ML060050335), the licensee submitted the annual SG tube inspection report in accordance with TS Section 5.6.9. A letter dated March 22, 2006 (ADAMS Accession No. ML060610209) summarized an October 4, 2005, conference call which the NRC staff participated in with the licensee to discuss the licensees SG tube inspections during their Cycle 12 refueling outage. The licensee provided additional information regarding their SG tube inspections during their Cycle 12 refueling outage by letters dated September 8, 2006 (ADAMS Accession No. ML062560349), and January 16, 2007 (ADAMS Accession No. ML070170225).
Byron Station, Unit No. 2 (Byron) has four Westinghouse Model D5 SGs, which are designated 2A through 2D. All four SGs were inspected during the Cycle 12 refueling outage (RFO). Each SG has 4,570 thermally-treated Alloy 600 tubes with an outside diameter of 0.750-inch and a nominal wall thickness of 0.043-inch. The tubes are hydraulically expanded for the full-depth of the tubesheet at each end. The tubes are supported by Type 405 stainless steel support plates with quatrefoil-shaped holes. The U-bend region of the tubes installed in Rows 1 through 9 was thermally-treated after bending in order to reduce stress.
The licensee provided the scope, extent, methods, and results of the Byron 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.
The staff has the following notes/observations as a result of reviewing the information provided by the licensee.
During the Cycle 12 RFO, the licensee performed a visual inspection of the secondary side steam drum and moisture separator region for SG 2B. As a result of the visual inspection, the only degradation identified was erosion in the primary moisture separator region. The licensee reported that 12 of the 16 carbon steel primary separator assemblies were missing the magnetite layer which provides corrosion protection to the assemblies. The licensee reported that they supplemented the visual inspection with ultrasonic thickness measurements in areas with the most apparent erosion. The largest percent nominal wall loss reported was 27 percent. Westinghouse performed SG thermal performance, structural adequacy, and loose parts assessments and determined that the as-found condition of the primary separator assemblies is acceptable for continued operation for the next operating cycle. The licensee indicated that secondary side steam drum and moisture separator region inspections are planned for the Spring 2007 RFO for all four SGs.
There are several tubes (approximately 15 tubes) with wear at the tube support plates in the pre-heater region.
Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by their TSs. In addition, the NRC staff concludes that there are no technical issues that warrant follow-up actions 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: L. Miller Date: March 19, 2007