ML082540555
| ML082540555 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 09/18/2008 |
| From: | Thadani M Plant Licensing Branch IV |
| To: | Helfin A Union Electric Co |
| Thadani, M C, NRR/DORL/LP4, 415-1476 | |
| References | |
| TAC MD7372 | |
| Download: ML082540555 (4) | |
Text
September 18, 2008 Mr. Adam C. Heflin Senior Vice President and Chief Nuclear Officer Union Electric Company P.O. Box 620 Fulton, MO 65251
SUBJECT:
CALLAWAY PLANT, UNIT 1 -
SUMMARY
OF STAFF REVIEW OF RESULTS OF THE 2007 STEAM GENERATOR TUBE INSPECTIONS (TAC NO. MD7372)
Dear Mr. Heflin:
By letter dated October 25, 2007, as supplemented on June 11, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML073050323 and ML081710156, respectively), Union Electric Company (the licensee) submitted information pertaining to the results of the 2007 steam generator tube inspection performed at Callaway Plant, Unit 1. These inspections were performed during the 15th refueling outage.
The U.S. Nuclear Regulatory Commission (NRC) staff has completed its review of the report and supplemental information and concludes that the licensee has provided the information required by its technical specifications and no additional follow-up is required at this time. The NRC staff=s summary of its review is enclosed.
If you have any questions regarding this matter, please contact me at (301) 415-1476.
Sincerely,
/RA by Balwant K. Singal for/
Mohan C. Thadani, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-483
Enclosure:
As stated cc w/encl: See next page
ML082540555 NRR-106
(*) memo dated 6/30/08 OFFICE NRR/LPL4/GE NRR/LPL4/PM NRR/LPL4/LA DCI/CSGB/BC NRR/LPL4/BC NRR/LPL4/PM NAME LWilkins BSingal for MThadani JBurkhardt AHiser (*)
MMarkley MThadani Ssingal for DATE 9/18/08 9/17/08 9/16/08 6/30/08 9/18/08 9/18/08
Callaway Plant, Unit 1 (7/2/2008) cc:
John ONeill, Esq.
Pillsbury Winthrop Shaw Pittman LLP 2300 N. Street, NW Washington, DC 20037 Mr. Tom Elwood, Supervising Engineer Regulatory Affairs and Licensing AmerenUE P.O. Box 620 Fulton, MO 65251 Mr. Les H. Kanuckel, Manager Quality Assurance AmerenUE P.O. Box 620 Fulton, MO 65251 Mr. Luke Graessle, Manager Regulatory Affairs AmerenUE P.O. Box 620 Fulton, MO 65251 Mr. Scott Maglio Assistant Manager, Regulatory Affairs AmerenUE P.O. Box 620 Fulton, MO 65251 U.S. Nuclear Regulatory Commission Resident Inspector Office 8201 NRC Road Steedman, MO 65077-1302 Missouri Public Service Commission Governor Office Building 200 Madison Street P.O. Box 360 Jefferson City, MO 65102-0360 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 Mr. H. Floyd Gilzow Deputy Director for Policy Department of Natural Resources P.O. Box 176 Jefferson City, MO 65102-0176 Mr. Rick A. Muench, President and CEO Wolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KA 66839 Certrec Corporation 4200 S. Hulen, Suite 422 Fort Worth, TX 76109 Technical Services Branch Chief FEMA Region VII 2323 Grand Blvd., Suite 900 Kansas City, MO 64108-2670 Kathleen Logan Smith, Executive Director and Kay Drey, Representative, Board of Directors Missouri Coalition for the Environment 6267 Delmar Blvd., Suite 2E St. Louis, City, MO 63130 Mr. Lee Fritz, Presiding Commissioner Callaway County Courthouse 10 E. Fifth Street Fulton, MO 65251 Mr. Keith G. Henke, Planner III Division of Community and Public Health Office of Emergency Coordination Missouri Department of Health and Senior Services 930 Wildwood Drive P.O. Box 570 Jefferson City, MO 65102 Mr. Scott Clardy, Director Section for Environmental Public Health Missouri Department of Health and Senior Services 930 Wildwood Drive P.O. Box 570 Jefferson City, MO 65102 Director, Missouri State Emergency Management Agency P.O. Box 116 Jefferson City, MO 65102-0116
SUMMARY
OF STAFF=S REVIEW OF 2007 STEAM GENERATOR TUBE INSPECTIONS AT CALLAWAY PLANT, UNIT 1 TAC NO. MD7372 DOCKET NO. 50-483 By letters dated October 25, 2007, and June 11, 2008 (Agencywide Documents Access and Management System (ADAMS Accession Nos. ML073050323 and ML081710156, respectively),
Union Electric Company (the licensee) submitted information pertaining to the 2007 steam generator tube inspections performed at Callaway Plant, Unit 1 during the 15th refueling outage.
Callaway has four Framatone-designed 73/19T steam generators (SGs) that were installed at the plant in 2005. Each SG has 5872 thermally-treated Alloy 690 tubes, which have an outside diameter of 0.75 inches and a wall thickness of 0.043 inches. The tubes are hydraulically expanded throughout the entirety of the tubesheet. The U-bend region of the tubes in rows 1 through 18 was stress relieved after bending. The tubes are supported by eight Type 410 stainless steel tube supports and anti-vibration bars (AVBs). The holes in the tube support plate are trifoil shaped.
The licensee provided the scope, extent, methods, and results of its 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. Based on its review of the reports submitted, the Nuclear Regulatory Commission (NRC) staff has the following observations and comments:
At the end of the 15th refueling outage, Callaway was in the first refueling outage after the replacement of the SGs. The SGs had operated 18 effective full power months since replacement.
A chemical excursion occurred on March 9, 2007. Action Level 3 limits (as defined in the Electric Power Research Institutes Secondary Water Chemistry Guidelines) on sodium, sulfate, and chloride were exceeded, so the plant was shut down. The licensee performed an assessment and concluded that the likelihood of accelerated tube degradation as a result of the event is small.
The only degradation mechanically observed during the outage was wear at the AVBs. A total of 36 tubes had wear indications.
Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by their technical specifications. In addition, the 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.
Enclosure