ML073180383

Closeout of Confirmatory Action Letter Requirements

ML073180383
Person / Time
Site:	Braidwood
Issue date:	11/14/2007
From:	Coutu T Exelon Generation Co, Exelon Nuclear
To:	Dyer J Document Control Desk, Office of Nuclear Reactor Regulation
References
BW070096, TAC MD4134, TAC MD4135, NRR-07-008
Download: ML073180383 (5)

Text

November 14, 2007 CAL No. NRR-07-008 BW070096 Mr. J. E. Dyer, Director Office of Nuclear Reactor Regulation ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 Braidwood Station, Unit 1 Facility Operating License No. NPF-72 NRC Docket No, STN 50-456

Subject:

Closeout of Confirmatory Action Letter Requirements Braidwood Station Unit 1 (TAC NO. MD4134)

References:

(1) Letter from T. S. ONeill (Exelon Generation Company, LLC) to U. S. NRC, Supplemental Response Regarding Inspection and Mitigation of Alloy 600/82/1 82 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 Braidwood Station, Units 1 and 2 (TAC Nos.

MD4134 and MD4135), 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-07-008) have been completed for Braidwood Station Unit 1. The commitments involved: schedule for mitigation actions, enhanced Reactor Coolant System leakage monitoring, and inspection reporting requirements. All commitments were related to Alloy 82/1 82 pressurizer connection activities.

The details of the commitments and a summation of the closeout activities for Braidwood Station Unit 1 are provided in the attachment to this letter.

U. S. Nuclear Regulatory Commission Page 2 November 14, 2007 This submittal does not contain any additional Regulatory Commitments.

Should you have any questions concerning this letter, please contact Mr. David Gullott, Regulatory Assurance Manager, at (815) 417-2800.

Respec~tfully /~

1~ /

/ /~~L~-/ S~J~

Thomas Coutu Braidwood Station Site Vice President

Attachment:

Braidwood Station Unit 1 Confirmatory Action Letter Closeout CAL No.

NRR 07-008

Braidwood Station Unit 1 Confirmatory Action Letter Closeout CAL No. NRA 07-008 COMMITMENT COMPLETION DETAILS Exelon Generation Company, LLC (EGC) will Full structural weld overlays, with primary complete mitigation activities on the water stress corrosion cracking resistant pressurizer surge, spray, safety, and relief material, were installed on Braidwood Station nozzle butt welds and safe end butt welds Unit 1 pressurizer surge, spray, safety, and containing Alloy 82/i 82 material prior to relief nozzle-to-safe end butt welds containing December 31, 2007 for Braidwood Station Alloy 82/i 82 material. The overlays were Unit 1. completed in the Fall 2007 refueling outage (A1Ri3).

The pressurizer surge, spray, safety, and relief Mitigation activities were completed for nozzle butt welds and safe end butt welds Braidwood Station Unit 1 during the Ai Ri 3 containing Alloy 82/182 material will be refueling outage.

inspected within every 4 years, until mitigated.

Braidwood Station Unit 1 will adopt enhanced Braidwood Station Unit 1 adopted the unidentified leakage monitoring requirements. enhanced unidentified leakage monitoring These unidentified reactor coolant system requirements starting on February 28, 2007.

(RCS) leakage monitoring enhancements From that time until Unit 1 shutdown for the include: Al Ri 3 refueling outage on October 1, 2007, Daily measurement of unidentified RCS there were no instances of sustained elevated leakage leakage that required a Unit 1 shutdown.

Incorporation of two new action levels for the following unidentified RCS leakage scenarios:

• a 0.l0gpm 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.

• a 0.25gpm above a baseline sustained After restart from refueling outage Al Ri 3,1 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 and the mitigation, as described above, confirmed from sources other than the completed, Braidwood Station Unit 1 reverted pressurizer nozzle welds back to the standard Technical Specification required RCS leakage monitoring

• 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. requirements.

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 1 or Unit 2, as applicable, 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 82/182 pressurizer nozzles will be performed.

1 The return to service date from Al R13 was October 26, 2007.

Page 1 of 3

Braidwood Station Unit 1 Confirmatory Action Letter Closeout CAL No. NRA 07-008 COMMITMENT COMPLETION DETAILS Reports of any Alloy 82/i 82 pressurizer nozzle Since the initiation of this commitment on connections inspection results for Braidwood February 28, 2007 until the shutdown of Station Unit 1 will be submitted to the NRC Braidwood Station Unit 1 on October 1, 2007, within 60 days of the completion date of the there were no bare metal visual examinations inspection. This includes reports of any bare performed as a result of RCS leakage.

metal visual inspections as a result of increased RCS leak rate, and reports of any In accordance with the requirements of corrective or mitigative actions taken on the Bulletin 2004-01, Inspection of Alloy pressurizer surge, spray, safety, or relief 82/182/600 Materials Used in the Fabrication nozzle butt welds and safe end butt welds of Pressurizer Penetrations and Steam Space containing Alloy 82/1 82 material. Piping Connections at Pressurized-Water Reactors, Braidwood Station Unit i 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 Fall 2007 refueling outage at Braidwood Station Unit 1, dye penetrant examinations of all Alloy 82/i 82 pressurizer connections were performed.

There were no indications associated with primary water stress corrosion cracking (PWSCC).

Finally, all six Braidwood Station Unit 1 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.

Page 2 of 3

Braidwood Station Unit 1 Confirmatory Action Letter Closeout CAL No. NRR 07-008

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 2i, 2007 (2) Letter from J. E. Dyer (U. S. NRC) to C. M. Crane (Exelon Generation Company, LLC),

Confirmatory Action Letter Braidwood Station, Units 1 and 2 (TAC Nos. MD41 34 and MD41 35), dated March 22, 2007 (3) Letter from T. Coutu (Exelon Generation Company, LLC) to U. S. NRC, Second 10-Year Inservice Inspection Interval, Relief Request l2R-48, Structural Weld Overlays on Pressurizer Spray, Relief, Safety and Surge Nozzles and Associated Alternative Repair Techniques, dated February 23, 2007 (4) Letter from T. Coutu (Exelon Generation Company, LLC) to U. S. NRC, Pressurizer Weld Overlay Examination Results Related to Braidwood Station Relief Request 12R-48, dated November i, 2007 Page 3 of 3