ML081090185
| ML081090185 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 02/08/2008 |
| From: | Ridenoure R Southern California Edison Co |
| To: | Dyer J Office of Nuclear Reactor Regulation |
| References | |
| Download: ML081090185 (3) | |
Text
SOU5 I ERN CALIFORNIA Ross T. Ridenoure EDISON"
'VP and Site Manager "O
San Onofre Nuclear Generating Station An EDISON INTERNATIONAL" Company February 8, 2008 James E. Dyer, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555-0001.
Subject:
Docket No. 50-361 Completion of Actions and Commitments from Confirmatory Action Letter Re: Alloy. 82/182
.Pressurizer Butt Welds San Onofre Nuclear Generating Station, Unit 2
References:
- 1) Letter from J. E. Dyer (NRC) to R. M. Rosenblum (SCE) dated March 22, 2007,
Subject:
San Onofre Nuclear Generating Station,,Units 2 and 3-Confirmatory Action Letter (TAC Nos. MD4181 and MD4182)
- 2) Letter from A. E. Scherer (SCE) to Document Control Desk (NRC) dated March 7, 2007,
Subject:
Docket Nos. 50-361 and 50-362, Inspection and Mitigation of Alloy 82/182 Pressurizer Butt Welds, San Onofre Nuclear Generating Station, Units 2 and 3
- 3) Letter from A. E. Scherer (SCE) to Document Control Desk (NRC) dated December 24, 2007,
Subject:
Docket No. 50-361, Ultrasonic Test Results Related to Inspection (ISI) Interval Relief fRequest ISI 25 for the Use of Structural Weld Overlay and Associated Alternative Repair Techniques, San Onofre Nuclear Generating Station, Unit 2
- 4) Letter from James T. Reilly (SCE) to James E. Dyer (NRC) dated December 24, 2007,
Subject:
Docket No. 50-362, Completion of Actions and Commitments from Confirmatory Action Letter Re: Alloy 82/182 Pressurizer Butt Welds, San Onofre Nuclear Generating Station, Unit 3.
Dear Sir:
The purpose of this letter is to provide documentation of completion of the actions and' commitments addressed in your Confirmatory Action Letter dated March 22, 2007 (Reference 1) for San Onofre Nuclear Generating Station (SONGS) Unit 2. Reference 1 confirmed actions and commitments made by Southern California Edison regarding Mail Drop D45 P.O. Box 128 San Clemente, CA 92672 949-368-6255 PAX 86255 Fax: 949-368-6183 Ross. Ridenoure@sce.com
James E. Dyer, Director February 8, 2008 Alloy 82/182 butt welds in the pressurizers at the San Onofre Nuclear Generating Station, Units 2 and 3.
In October 2006, while performing inspections of its pressurizer Alloy 82/182 butt welds in accordance with Material Reliability Program (MRP)-i 39, another licensee of a pressurized water reactor discovered several circumferential indications in its pressurizer surge, safety, and relief nozzles. Because of the potential importance of this issue, SCE submitted a letter dated March 7, 2007 (Reference 2) to notify you of actions taken and planned for inspecting and mitigating Alloy 600/82/182 butt welds on pressurizer spray, surge, and safety nozzles at San Onofre Nuclear Generating Station (SONGS), Unit 2 and Unit 3.
As outlined in Reference 2, the only remaining pressurizer nozzle that was susceptible to Primary Water Stress Corrosion Cracking (PWSCC) failure was the surge line nozzle for each unit. Reference 2 provided a commitment that SCE would not operate SONGS Units 2 and 3 after December 31, 2007, until Units 2 and 3 were in compliance with the MRP-139 guidance. In addition, Reference. 2 provided a commitment that SCE would implement an enhanced Reactor Coolant System (RCS) leakage monitoring program for SONGS Units 2 and 3 which supplements the existing plant programs and procedures. The enhanced program would be in place at each unit until the pressurizer surge line butt welds were successfully brought into compliance with MRP-1 39.
Reference 1 confirmed these commitments with two clarifications:
.1. MRP-1 39 would be met through mitigation of the pressurizer surge line nozzle welds, and,
- 2. The NRC would be informed in writing if SCE revised the commitment to the enhanced leakage monitoring program, reporting requirements, or the commitment to have all pressurizer dissimilar metal welds compliant with MRPr139, prior to operation after December 31, 2007.
Reference 1 also provided a requirement to notify you in writing when SCE had completed these actions and commitments.
During the recent Unit 2 Cycle 15 refueling outage, mitigation of the Unit 2 pressurizer surge.line nozzle weld was completed and post-mitigation inspections were performed.
The results of these inspections were provided to the NRC by letter dated December 24, 2007 (Reference 3). No suspected flaw indications, such as lack of bond, weld flaws, planar flaws, or laminar flaws, were observed during the examinations.
As a result of the completion of the mitigation of the SONGS Unit 2 pressurizer surge line nozzle weld, SCE has satisfied the commitment to mitigate these welds and is no longer required to perform enhanced RCS leakage monitoring at SONGS Unit 2. This letter also satisfies the requirement for SONGS Unit 2 to notify you in writing that the actions and commitments of Reference 1 are complete.
James E. Dyer, Director February 8, 2008
)
Closure of actions and commitments from Reference 1 for Unit 3 was addressed by letter to you dated December 24, 2007 (Reference 4).
Should you have any questions, please contact Ms. Linda T. Conklin at 949-368-9443.
Sincerely, cc:
E. E. Collins, Regional Administrator, NRC Region IV N. Kalyanam, NRC Project Manager, San Onofre Units 2 and 3 C. C. Osterholtz, NRC Senior Resident Inspector, San Onofre Units 2 and 3 NRC Document Control Desk