BYRON 2007-0067, Closeout of Confirmatory Action Letter Requirements
| ML071560272 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 06/04/2007 |
| From: | Hoots D Exelon Generation Co, Exelon Nuclear |
| To: | Dyer J Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BYRON 2007-0067, TAC MD4137, NRR-07-012 | |
| Download: ML071560272 (5) | |
Text
Exelon Generation Company, LLC www.exeloncorpconi Exek,n. Nuclear Byron Station 4450 North German Church Road Byron, ft 61010-9794 CAL No. NRR-07-012 June 4, 2007 LTR: BYRON 2007-0067 File: 1.10.0101 Mr. J. E. Dyer, Director Office of Nuclear Reactor Regulation ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 Byron Station, Unit 2 Facility Operating License No. NPF-66 NRC Docket No. STN 50-455
Subject:
Closeout of Confirmatory Action Letter Requirements Byron Station Unit 2 (TAC NO. MD4137)
Referéncés: (1) Letter from T. S. ONeill (Exelon Generation Company, LLC) to U. S. NRC, Supplemental Response Regarding Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds, dated February 21, 2007 (2) Letter from J. E. Dyer (U. S. NRC) to C. M. Crane (Exelon Generation Company, LLC), Confirmatory Action Letter Byron Station, Unit 2 (TAC NO.
MD4137), dated March 22, 2007
Dear Mr. Dyer:
The purpose of this letter is to notify you that the actions and commitments identified in the Reference 1 submittal and confirmed in the Reference 2 Confirmatory Action Letter (CAL No.
NRR-07-012) have been completed for Byron Station Unit 2. The commitments involved:
schedule for mitigation actions, enhanced Reactor Coolant System leakage monitoring, and inspection reporting requirements. All commitments were related to Byron Station Unit 2 Alloy 82/1 82 pressurizer connection activities.
The details of the commitments and a summation of the closeout activities are provided in the attachment to this letter.
This submittal does not contain any additional Regulatory Commitments.
U. S. Nuclear Regulatory Commission Page 2 June 1,2007 Should you have any questions concerning this letter, please contact William Grundmann at (815) 406-2800.
Respectfully, David M. oots Byron Station Site Vice President
Attachment:
Byron Station Unit 2 Confirmatory Action Letter Closeout CAL No.
NRR 07-012
Exelon Generation Company, LLC www.exeloncorpconi Exek,n. Nuclear Byron Station 4450 North German Church Road Byron, ft 61010-9794 CAL No. NRR-07-012 June 4, 2007 LTR: BYRON 2007-0067 File: 1.10.0101 Mr. J. E. Dyer, Director Office of Nuclear Reactor Regulation ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 Byron Station, Unit 2 Facility Operating License No. NPF-66 NRC Docket No. STN 50-455
Subject:
Closeout of Confirmatory Action Letter Requirements Byron Station Unit 2 (TAC NO. MD4137)
Referéncés: (1) Letter from T. S. ONeill (Exelon Generation Company, LLC) to U. S. NRC, Supplemental Response Regarding Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds, dated February 21, 2007 (2) Letter from J. E. Dyer (U. S. NRC) to C. M. Crane (Exelon Generation Company, LLC), Confirmatory Action Letter Byron Station, Unit 2 (TAC NO.
MD4137), dated March 22, 2007
Dear Mr. Dyer:
The purpose of this letter is to notify you that the actions and commitments identified in the Reference 1 submittal and confirmed in the Reference 2 Confirmatory Action Letter (CAL No.
NRR-07-012) have been completed for Byron Station Unit 2. The commitments involved:
schedule for mitigation actions, enhanced Reactor Coolant System leakage monitoring, and inspection reporting requirements. All commitments were related to Byron Station Unit 2 Alloy 82/1 82 pressurizer connection activities.
The details of the commitments and a summation of the closeout activities are provided in the attachment to this letter.
This submittal does not contain any additional Regulatory Commitments.
U. S. Nuclear Regulatory Commission Page 2 June 1,2007 Should you have any questions concerning this letter, please contact William Grundmann at (815) 406-2800.
Respectfully, David M. oots Byron Station Site Vice President
Attachment:
Byron Station Unit 2 Confirmatory Action Letter Closeout CAL No.
NRR 07-012
Byron Station Unit 2 Confirmatory Action Letter Closeout CAL No. NRR 07-012 COMMITMENT COMPLETION DETAILS Exelon Generation Company, LLC (EGC) Full structural weld overlays, with primary will complete mitigation activities on the water stress corrosion cracking resistant pressurizer surge, spray, safety, and relief material, were installed on Byron Station nozzle butt welds and safe end butt welds Unit 2 pressurizer surge, spray, safety, and containing Alloy 82/1 82 material [For Byron relief nozzle butt welds and safe end butt Station Unit 2] by December 31, 2007. welds containing Alloy 82/1 82 material.
The overlays were completed in the Spring 2007 refueling outage (B2R13).
Byron Station Unit 2 will adopt enhanced Byron Station Unit 2 adopted the enhanced unidentified leakage monitoring unidentified leakage monitoring requirements. These unidentified reactor requirements starting on February 28, coolant system (RCS) leakage monitoring 2007. From that time until Unit 2 shutdown enhancements include: for the B2R13 refueling outage on April 1, Daily measurement of unidentified RCS 2007, there were no instances of sustained leakage elevated leakage that required a Unit 2 shutdown.
Incorporation of two new action levels for the following unidentified RCS leakage scenarios:
a 0.10 gpm change from one day to the next, sustained for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with at least 0.10 gpm not confirmed from sources other than pressurizer nozzle welds.
After restart from refueling outage B2R13,1 a 0.25 gpm above a baseline sustained and the mitigation, as described above, for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with at least 0.25 gpm not completed, Byron Station Unit 2 reverted confirmed from sources other than the back to the standard Technical pressurizer nozzle welds Specification required RCS leakage monitoring requirements.
Once the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> evaluation period, i.e.
the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> period of sustained increased leakage, is complete, and the leakrate is still elevated, Byron Station Unit 2 will be placed in MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in MODE 5 within 36 additional hours and a bare metal visual inspection of unmitigated Alloy 82/1 82 pressurizer nozzles will be performed.
1 The return to service date from B2R13 was May 3, 2007.
Byron Station Unit 2 Confirmatory Action Letter Closeout CAL No. NRR 07-012 COMMITMENT COMPLETION DETAILS Reports of any Alloy 82/182 pressurizer Since the initiation of this commitment on nozzle connections inspection results for February 28, 2007 until the shutdown of Byron Station Unit 2 will be submitted to Byron station Unit 2 on April 1, 2007, there the NRC within 60 days of the completion were no bare metal visual examinations date of the inspection. This includes performed as a result of RCS leakage.
reports of any bare metal visual inspections as a result of increased RCS In accordance with the requirements of leak rate, and reports of any corrective or Bulletin 2004-01, Inspection of Alloy mitigative actions taken on the pressurizer 82/182/600 Materials Used in the surge, spray, safety, or relief nozzle butt Fabrication of Pressurizer Penetrations welds and safe end butt welds containing and Steam Space Piping Connections at Alloy 82/182 material. Pressurized-Water Reactors, Byron Station Unit 2 performed bare metal visual examinations of the pressurizer steam space connections. There were no indications of pressurizer pressure boundary leakage at any of the connections.
In addition, as part of the installation of full structural overlays on the pressurizer connections during the Spring 2007 refueling outage at Byron Station Unit 2, dye penetrant examinations of all Alloy 82/182 pressurizer connections were performed. There were no indications.
Finally, all six Byron Station Unit 2 pressurizer connections weld overlays were volumetrically examined in accordance with the requirements of the Reference 3 relief request. The results of these examinations were provided to the NRC in the Reference 4 submittal.
Byron Station Unit 2 Confirmatory Action Letter Closeout CAL No. NRR 07-012
References:
(1) Letter from T. S. ONeill (Exelon Generation Company, LLC) to U. S. NRC, Supplemental Response Regarding Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds, dated February 21, 2007 (2) Letter from J. E. Dyer (U. S. NRC) to C. M. Crane (Exelon Generation Company, LLC), Confirmatory Action Letter Byron Station, Unit 2 (TAC NO. MD4137), dated March 22, 2007 (3) Letter from D. M. Hoots (Exelon Generation Company, LLC) to U. S. NRC, Third 10-Year Inservice Inspection Interval, Relief Request 13R-08, Preventive Weld Overlays on Pressurizer Spray, Relief, Safety and Surge Nozzles and Associated Alternative Repair Techniques, dated April 28, 2006 (4) Letter from D. M. Hoots (Exelon Generation Company, LLC) to U. S. NRC, Pressurizer Weld Overlay Examination Results Related to Byron Station Relief Request 13R-08, dated May 4, 2007