ML091180132
| ML091180132 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 05/11/2009 |
| From: | David M Plant Licensing Branch III |
| To: | Pardee C Exelon Generation Co |
| david marshall NRR/DORL 415-1547 | |
| References | |
| TAC MD9235 | |
| Download: ML091180132 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 11, 2009 Mr. Charles G. Pardee President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BYRON STATION, UNIT NO.1 - REVIEW OF SPRING 2008 STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT (TAC NO. MD9235)
Dear Mr. Pardee:
By letter dated June 30,2008 (Agencywide Documents Access and Management System Accession No. ML081830083), Exelon Generation Company, LLC (the licensee) submitted a report related to the steam generator tube inservice inspections for the spring 2008, refueling outage at the Byron Station (Byron), Unit No.1, in accordance with the plant's technical specifications (TSs).
The Nuclear Regulatory Commission (NRC) staff has completed its review of the report and concludes that you have provided the information required by the Byron TSs, and that no additional follow-up is required at this time. A copy of the NRC staff evaluation is enclosed.
Sincerely,
/7t'1~
M~hall J. David, Se lor ojec Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-454
Enclosure:
Evaluation of Steam Generator Tube Inservice Inspection Report cc w/encl: Distribution via ListServ
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 OFFICE OF NUCLEAR REACTOR REGULATION EVALUATION OF STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT FOR SPRING 2008 REFUELING OUTAGE BYRON STATION, UNIT NO.1 DOCKET NO. 50-454 By letter dated June 30, 2008 (Agencywide Documents Access and Management System Accession No. ML081830083), Exelon Generation Company, LLC (the licensee) submitted information pertaining to the steam generator (SG) tube inservice inspection performed at Byron Station (Byron), Unit No.1, during the spring 2008 refueling outage (RFO) 15.
Byron 1 has four Babcock & Wilcox SGs. Each SG contains 6,633 thermally-treated Alloy 690 tubes. Each tube has, a nominal wall thickness of 0.040 inches. 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.
The licensee provided the scope, extent, methods, and results of their SG tUbe inspections in the document referenced above. In addition, the licensee described corrective actions (i.e., tube plugging) taken in response to the inspection findings. The tubes in all four SGs were inspected during this outage.
After review of the information provided by the licensee, the U.S. Nuclear Regulatory Commission (NRC) staff has the following comments/observations:
- The Byron 1 SGs are currently in the 144 effective full power month (EFPM) period. At the time of RF015, the SGs had operated approximately 102 EFPM in the 144 EFPM period.
- The licensee reported that bobbin coil examinations of the U-bend region were performed and revealed fan bar wear. A total of 146 indications in 125 tubes were reported. None of the tubes exceeded the 40 percent through wall repair limit and no tubes were plugged due to fan bar wear. During the last SG inspections in 2005, only 46 indications of fan bar wear in 42 tubes were identified.
- The licensee reported structural limits for various forms of degradation. The NRC staff did not review these limits in detail; however, the limits appear reasonable.
ENCLOSURE
- 2 Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by the plant's technical specifications. In addition, the NRC staff concludes that there are no technical issues that warrant follow-up action at this time, because 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: A. Obodoako Date: May 11, 2009
May 11,2009 Mr. Charles G. Pardee President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 SUB~IECT:
BYRON STATION, UNIT NO.1 - REVIEW OF SPRING 2008 STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT (TAC NO. MD9235)
Dear Mr. Pardee:
By letter dated June 30, 2008 (Agencywide Documents Access and Management System Accession No. ML081830083), Exelon Generation Company, LLC (the licensee) submitted a report related to the steam generator tube inservice inspections for the spring 2008, refueling outage at the Byron Station (Byron), Unit No.1, in accordance with the plant's technical specifications (TSs).
The Nuclear Regulatory Commission (NRC) staff has completed its review of the report and concludes that you have provided the information required by the Byron TSs, and that no additional follow-up is required at this time. A copy of the NRC staff evaluation is enclosed.
Sincerely, IRA!
Marshall J. David, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-454
Enclosure:
Evaluation of Steam Generator Tube Inservice Inspection Report cc w/encl: Distribution via ListServ DISTRIBUTION:
PUBLIC RidsNrrPMByron Resource AObodoako, NRR LPL3-2 RlF RidsRgn3MailCenter Resource RidsOgcRp Resource RidsNrrDorlLpl3-2 Resource RidsNrrDciCsgb Resource RidsAcrsAcnw_MailCTR Resource RidsNrrLATHarris Resource KKarwoski, NRR ADAMS Accession No*.. ML091180132
- SE date NRR-106 OFFICE LPL3-2/PM LPL3-2/LA DCI/CSGB/BC LPL3-2/BC NAME MDavid THarris MGavrilas*
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DATE 05/01/09 04/29/09 02/02/09 05/11/09 OFFICIAL RECORD COpy