ML081920287
| ML081920287 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 07/10/2008 |
| From: | Bryan Hanson Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BW080069, TAC MD4134, TAC MD4135, TAC MD7295, NRR-07-008 | |
| Download: ML081920287 (6) | |
Text
E July 10, 2008 CAL No, NRR-07-008 BW080069 Mr. Eric Leeds, Director Office of Nuclear Reactor Regulation ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Facility Operating License Nos. NPF-72 and NPF-77 NRC Docket Nos. STN 50-456 and STN 50-457
Subject:
Closeout of Confirmatory Action Letter Requirements Braidwood Station Unit 2 (TAC NO. MD7295)
References:
(1) Letter from T. S. ONeill (Exelon Generation Company, LLC) to U. S. Nuclear Regulatory Commission, 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. Nuclear Regulatory Commission) to C. M. Crane (Exelon Generation Company, LLC), Confirmatory Action Letter Braidwood Station, Units 1 and 2 (TAC NOS. MD4134 and MD41235), dated March 22, 2007 (3) Letter from T. Coutu (Exelon Generation Company, LLC) to J. E. Dyer (U. S.
Nuclear Regulatory Commission), Closeout of Confirmatory Action Letter Requirements Braidwood Station Unit 1 (TAC NO. MD4134), dated November 14, 2007
Dear Mr. Leeds:
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-07-008) have been completed for Braidwood 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 Braidwood Station Unit 2 Alloy 82/182 pressurizer connection activities.
The details of the commitments and a summation of the closeout activities are provided in the attachment to this letter.
U. S. Nuclear Regulatory Commission Page 2 July 10, 2008 Reference 3 provided the CAL No. NRR-07-008 completion activities for Braidwood Station Unit 1. Therefore, although this submittal documents completion of CAL No.
NRR-07-008 and Technical Assignment Control (TAC) number MD7295 actions for Braidwood Station Unit 2, it is being docketed for Braidwood Unit 1 and Unit 2 since the completion of Braidwood Unit 2 activities now completes all CAL No. NRR-07-008 actions for Braidwood Station, This submittal does not contain any additional Regulatory Commitments.
Should you have any questions concerning this letter, please contact David Gullott at (815) 417-2800.
~ulIy, Byran Hanson Site Vice President Braidwood Station
Attachment:
Braidwood Station Unit 2 Confirmatory Action Letter Closeout CAL No.
NRR 07-008
Attachment Braidwood Station Unit 2 Confirmatory Action Letter Closeout CAL No. NRR 07-008 COMMITMENT COMPLETION DETAILS (References I and 2)
Braidwood Station Unit 2 will develop Braidwood Station developed plans and contingency plans to shutdown in 2007 schedules for the shutdown and mitigation and perform mitigation. of the Unit 2 Alloy 82/182 pressurizer connections in 2007. With NRC approval If the NRC agrees that the Materials of the Materials Reliability Project refined Reliability Project sponsored refined crack crack growth rate project and its growth project results provide reasonable applicability to Braidwood Station Unit 2 assurance that there is sufficient time (Reference 3), the contingency plans were between leak and break, then EGC will put on hold.
complete inspection or mitigation activities on the pressurizer surge, spray, safety, As stated above, Reference 3 provided and relief nozzle butt welds and safe end initial NRC approval for mitigation in Spring butt welds containing Alloy 82/182 material 2008 for Braidwood Unit 2 Alloy 82/1 82 prior to the completion of Braidwood pressurizer connections. This position was Station Unit 2 cycle 13 refueling outage. reaffirmed after NRC evaluation of additional information (Reference 4).
Full structural weld overlays, with primary water stress corrosion cracking resistant material, were installed on Braidwood Station Unit 2 pressurizer surge, spray, safety, and relief nozzle butt welds and safe end butt welds containing Alloy 82/182 material. The overlays were completed in the Spring 2008 refueling outage (A2R13) in accordance with the requirements of the Reference 5 relief request, the Reference 6 NRC Safety Evaluation Report and the supplemental information provided in Reference 7.
The pressurizer surge, spray, safety, and Mitigation activities were completed for relief nozzle butt welds and safe end butt Braidwood Station Unit 2 during the A2R13 welds containing Alloy 82/182 material will refueling outage. Future examinations will be inspected within every 4 years, until be performed in accordance with the mitigated. requirements of Relief Request 12R-48 (Reference 6).
Page 1 of 4
Attachment Braidwood Station Unit 2 Confirmatory Action Letter Closeout CAL No. NRR 07-008 COMMITMENT COMPLETION DETAILS (References I and 2)
Braidwood Station Unit 2 will adopt Braidwood Station Unit 2 adopted the enhanced unidentified leakage monitoring enhanced 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 A2R1 3 refueling outage on April 21, Daily measurement of unidentified RCS 2008, 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 After restart from refueling outage A2R1 3 scenarios: on May 17, 2008, and the mitigation, as described above, completed, RCS leakage a 0.10 gpm change from one day to monitoring is performed in accordance with 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 the standard Technical Specification least 0.10 gpm not confirmed from requirements.
sources other than pressurizer nozzle welds.
- a 0.25 gpm above a baseline 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 0.25 gpm not confirmed from sources other than the pressurizer nozzle welds.
- 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, Braidwood 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.
Page 2 of 4
Attachment Braidwood Station Unit 2 Confirmatory Action Letter Closeout CAL No. NRR 07-008 COMMITMENT COMPLETION DETAILS (References I and 2)
Reports of any Alloy 82/1 82 pressurizer Since the initiation of this commitment on nozzle connections inspection results for February 28, 2007 until the shutdown of Braidwood Station Unit 2 will be submitted Braidwood station Unit 2 on April 21, 2008, to the NRC within 60 days of the there were no bare metal visual completion date of the inspection. This examinations performed as a result of RCS includes reports of any bare metal visual leakage.
inspections as a result of increased RCS leak rate, and reports of any corrective or In accordance with the requirements of mitigative actions taken on the pressurizer Bulletin 2004-01, Inspection of Alloy surge, spray, safety, or relief nozzle butt 82/182/600 Materials Used in the welds and safe end butt welds containing Fabrication of Pressurizer Penetrations Alloy 82/1 82 material. and Steam Space Piping Connections at Pressurized-Water Reactors, Braidwood 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 (Reference 9).
In addition, as part of the installation of full structural overlays on the pressurizer connections during the Spring 2008 refueling outage at Braidwood Station Unit 2, dye penetrant examinations of all Alloy 82/182 pressurizer connections were performed. There were no indications associated with primary water stress corrosion cracking (PWSCC).
Finally, all six Braidwood Station Unit 2 pressurizer connections weld overlays were volumetrically examined in accordance with the requirements of the Reference 6 Relief Request. The results of these examinations were provided to the NRC in the Reference 8 submittal.
Page 3 of 4
Attachment Braidwood Station Unit 2 Confirmatory Action Letter Closeout CAL No. NRR 07-008
References:
(1) Letter from 1. 5. 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), ConfirmatoryAction Letter Braidwood Station, Units 1 and 2 (TAC Nos.
MD4134 and MD4135), dated March 22, 2007 (3) Letter from C. Haney (U. S. Nuclear Regulatory Commission) to C. M. Crane (Exelon Generation Company, LLC), Braidwood Station, Unit 2 Evaluation of Finite Element Analysis in Support of Alloy 82/182 Pressurizer Butt Weld Inspections in 2008 as Provided by Confirmatory Action Letter NRR-07-008 (TAC No. MD4135), dated September 7, 2007 (4) Letter from C. Haney (U. S. Nuclear Regulatory Commission) to C. G. Pardee (Exelon Generation Company, LLC), Braidwood Station, Unit 2 Evaluation of New Information Related to Alloy 82/182 Pressurizer Butt Weld Inspections Re:
Confirmatory Action Letter NRR-07-008 (TAC No. MD7295), dated March 14, 2008 (5) Letter from T. Coutu (Exelon Generation Company, LLC) to (U. S. Nuclear Regulatory Commission), Second 10-Year Inservice Inspection Interval, Relief Request 12R-48, Structural Weld Overlays on Pressurizer Spray, Relief, Safety and Surge Nozzle Safe-ends and Associated Alternative Repair Techniques, dated February 23, 2007 (6) Letter from R. Gibbs (U. S. Nuclear Regulatory Commission) to C. M. Crane (Exelon Generation Company, LLC), Braidwood Station, Units 1 and 2 Evaluation of Inservice Inspection Program Relief Request I2R-48 Pertaining to Structural Weld Overlays on Pressurizer Spray, Relief, Safety, and Surge Nozzle Safe Ends (TAC Nos. MD4590 and MD4591), dated September 17, 2007 (7) Letter from P. R. Simpson (Exelon Generation Company, LLC) to U. S. Nuclear Regulatory Commission, Additional Information Regarding Braidwood Station Relief Request 12R-48, dated April 1, 2008 (8) Letter from B. Hanson (Exelon Generation Company, LLC) to U. S. Nuclear Regulatory Commission, Pressurizer Weld Overlay Examination Results Related to Braidwood Station Relief Request l2R-48, dated May 19, 2008 (9) Letter from B. Hanson (Exelon Generation Company, LLC) to U. S. Nuclear Regulatory Commission, Braidwood Station Unit 2 60-Day Response to NRC Bulletin 2004-01, Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Connection at Pressurized-Water Reactors, dated June 25, 2008 Page 4 of 4