ML103480586
| ML103480586 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 12/13/2010 |
| From: | Becker J Pacific Gas & Electric Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| DCL-1 0-160 | |
| Download: ML103480586 (5) | |
Text
Pacific Gas and Electric Company December 13, 2010 PG&E Letter DCL-1 0-160 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20852 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 James R. Becker Site Vice President Diablo Canyon Power Plant Mail Code 104/ 5/ 601
- p. O. Box 56 Avila Beach, CA 93424 805.545.3462 Internal: 691.3462 Fax: 805.545.6445 Response to Telephone Conference Call Held on November 10, 2010, Between the U.S. Nuclear Regulatory Commission and Pacific Gas and Electric Company Concerning Responses to Requests for Additional Information Related to the Diablo Canyon Nuclear Power Plant, Units 1 and 2, License Renewal Application
Dear Commissioners and Staff:
By letter dated November 23, 2009 (Reference 1), Pacific Gas and Electric Company (PG&E) submitted an application to the U.S. Nuclear Regulatory Commission (NRC) for the renewal of Facility Operating Licenses DPR-80 and DPR-82, for Diablo Canyon Power Plant (DCPP) Units 1 and 2, respectively. The application included the license renewal application (LRA), and Applicant's Environmental Report - Operating License Renewal Stage.
On November 10, 2010, a telephone conference between the NRC and representatives of PG&E was held to obtain clarification on the applicant's response to request for additional information (RAI) submitted to the NRC in a letter dated.
September 30, 2010, regarding the One-Time Inspection of ASME Code Class 1 Small-Bore Piping Aging Management Program.
By PG&E Letter DCL-1 0-146, dated November 24,2010 (ADAMS Accession Number ML103280467), PG&E provided supple*mental information to the RAI response for which the staff requested.
This letter supersedes PG&E Letter DCL-1 0-146 in its entirety and corrects an inconsistency in the dates used in that letter. The technical content in this submittal did not change from that submitted in PG&E Letter DCL-1 0-146.
A member of the STARS (Strategic Teaming and Resource Sharing)
Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- San Onofre
- South Texas Project
- Wolf Creek
Document Control Desk December 13,2010 Page 2 PG&E Letter DCL-10-160 contains supplemental information to the RAI response for which the staff requested. PG&E amends a commitment in LRA Table A4-1, License Renewal Commitments, shown in Enclosure 2. LRA Amendment 26 is included in showing the amended pages with line-in/line-out annotations.
Enclosures 1 and 2 supersede previously submitted information regarding the One-Time Inspection of ASME Code Class 1 Small-Bore Piping Aging Management Program.
If you have any questions regarding this response, please contact Mr. Terence L. Grebel, License Renewal Project Manager, at (805) 545-4160.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on December 13,2010.
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James
. Becker c:::::~~~=-=-==*"""=-
Site Vice President TLG/50361762 I 50363702 Enclosures cc:
Diablo Distribution cc/enc: Elmo E. Collins, NRC Region IV Regional Administrator Nathanial B. Ferrer, NRC Project Manager, License Renewal Kimberly J. Green, NRC Project Manager, License Renewal Michael S. Peck, NRC Senior Resident Inspector Alan B. Wang, NRR Project Manager A
member of the STARS (Strategic Teaming and Resource Sharing)
Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- San Onofre
- South Texas Project
- Wolf Creek PG&E Letter DCL-10-160 Page 1 of 1 PG&E Supplement to Telephone Conference Call Held on November 10, 2010, Concerning Response to Request for Additional Information (RAI) Submitted to the NRC in a Letter Dated September 30, 2010, Regarding the One-Time Inspection of ASME Code Class 1 Small-Bore Piping Aging Management Program Diablo Canyon Power Plant (DCPP) will volumetrically examine 10 percent, with a maximum of 25, of the small bore socket welds and 10 percent, with a maximum of 25, of the butt welds within the population of ASME Class-1 piping NPS less than 4 inches on each unit. Currently, DCPP has 696 socket welds in Unit 1, 841 socket welds in Unit 2, 134 butt welds in Unit 1, and 133 butt welds in Unit 2. Based on the current weld count, this would result in the examination of 25 socket welds for Unit 1, 25 socket welds for Unit 2, 13 butt welds for Unit 1 and 13 butt welds for Unit 2. DCPP may perform opportunistic destructive examination of welds in lieu of volumetric examination with one destructive examination being equivalent to two volumetric examinations. The sample selection methodology will take into account damage mechanisms such as thermal fatigue, vibration induced fatigue, and stress corrosion cracking. DCPP will determine potential damage mechanisms for each weld by using site specific analysis, MRP-146 guidance, and plant operating experience. These documents currently show thermal fatigue as the prevalent damage mechanism. Plant operating experience will also be considered for the socket weld examination sample to validate the effectiveness of past corrective actions.
The volumetric examination of these welds will occur within 6 years prior to the period of extended operation.
The commitment in LRA Table A4-1 has been amended to inspect 10 percent, with a maximum of 25, of the small bore socket welds and 10 percent, with a maximum of 25, of the butt welds within the population of ASME Class-1 piping NPS less than 4 inches on each unit. See amended LRA Table A4-1 in Enclosure 2.
PG&E Letter DCL-10-160 Page 1 of 2 LRA Amendment 26 LRA Section Table A4-1 PG&E Letter DCL-10-160 Page 2 of 2 Appendix A Final Safety Analysis Report Supplement Table A4-1 License Renewal Commitments Item #
Commitment LRA Section Implementation Schedule 39 DCPP will volumetrically examine 10%, with a maximum of 25, of the small bore socket welds and 10%, with a maximum of 25, of the butt welds within the population of ASME Class-1 piping NPS less than 4-inches on each unit. Currently, DCPP has 696 socket welds in Unit 1, 841 socket welds in Unit 2, 134 butt welds in Unit 1, and 133 butt welds in Unit 2. Based on the current weld count, this would result in the examination of 25 socket welds for Unit 1, 25 socket welds for Unit 2, 13 butt welds for Unit 1 and 13 butt welds for Unit 2. DCPP may perform opportunistic destructive examination of welds in lieu of volumetric examination with 1 destructive examination being equivalent to 2 volumetric examinations. DCPP will volumetrically examine 25 small bore welds per unit within the population of ASME Class-1 piping NPS 4-inches and less. The sample will contain socket welds and butt welds proportional to the number of socket welds and butt welds within the population. Based on the current weld count this would result in 8 butt welds and 17 socket welds in DCPP Unit-1 and 7 butt welds and 18 socket welds in Unit-2. The volumetric examination of these welds will occur within 10 years prior to the period of extended operation.
B2.1.19 During the 6 years Pprior to the period of extended operation