ML12221A367

Request for Additional Information Email, Request for Alternative No. RI-ISI-INT3 to ASME Code Requirements for Class 1 and 2 Piping Welds, Third 10-Year Inservice Inspection Interval

ML12221A367
Person / Time
Site:	Diablo Canyon
Issue date:	08/08/2012
From:	Joseph Sebrosky Plant Licensing Branch IV
To:	Soenen P Pacific Gas & Electric Co
Sebrosky J
References
TAC ME7854, TAC ME7855
Download: ML12221A367 (2)

Text

From: Sebrosky, Joseph To: Soenen, Philippe R Cc: "Baldwin, Thomas (DCPP)"; Hoffman, Keith; Patel, Jigar; Burkhardt, Janet; Chen, Qiao-Lynn

Subject:

Request for Additional Information associated with relief request for risk-informed inservice inspection (ME7854, ME7855)

Date: Wednesday, August 08, 2012 2:53:46 PM

Philippe, By letter dated January 20, 2012, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12025A084) Pacific Gas and Electric (PG&E) submitted for staff review and approval Relief Request RI-ISI-INT3-U1&2, which requests authorization to continue implementing a risk-informed inservice inspection (RI-ISI) program based on Electric Power Research Institute TR-112657 for American Society of Mechanical Engineers (ASME) Class 1 and 2 piping welds for the third 10-year inspection interval at the Diablo Canyon Power Plant Units 1 & 2 (DCPP).

Based on a review of the submittal, the NRC staff has determined that the following additional information (RAI) is required in order to complete its review. The request for additional information was discussed with Mr. Soenen on August 8, 2012. It was agreed that a response to these RAIs would be provided by September 7, 2012. Should the NRC determine that this RAI is no longer necessary prior to the scheduled date, the request will be withdrawn. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-1132 or via e-mail at joseph.sebrosky@nrc.gov. The NRC staff has determined that no security-related or proprietary information is contained herein.

Sincerely, Joe Sebrosky REQUEST FOR ADDITIONAL INFORMATION Note: Questions 1 through 6 are from the piping and non-destructive examination branch, and question 7 is from the probabilistic risk assessment licensing branch

1. The NRC issued rulemaking on June 21, 2011 which requires licensees to follow an augmented inservice inspection program in accordance with ASME Code Case N-770-1, Alternative Examination Requirements and Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated With UNS N06082 or UNS W86182 Weld Filler Material With or Without Application of Listed Mitigation Activities, and limitations listed in Title 10 of Code of Federal Regulations 50.55a(g)(6)(ii)(F). In addition, the NRC held a public meeting to discuss the June rulemaking and the implementation of Code Case N-770-1 on July 12, 2011.

Agencywide Document Access and Management System (ADAMS) accession number # ML112240818 documents the NRC summary of that meeting. The NRC staffs concern is that, the welds required to be examined in accordance with the augmented program required by 50.55a(g)(6)(ii)(F) should not be counted as exams selected to satisfy the RI-ISI program. Please describe how DCPP will address the requirements of the June 2011 rulemaking and ASME Code Case N-770-1 in implementing Relief Request RI-ISI-INT3-U1&2.

2. Please describe how the proposed RI-ISI program will satisfy the requirements of

IWB-2412 and IWC-2412 for percentage of examinations completed.

3. IWB-2420(a) and IWC-2420(a), Successive Examinations require that the sequence of component examinations which was established during the first inspection interval shall be repeated during each successive inspection interval, to the extent practical. This requirement is to ensure components are examined on a once per 10-year frequency to the extent practical. Please discuss how the proposed RI-ISI program satisfies this requirement.

4. The original RI-ISI program required 10% of the ASME Class 1 piping non-socket welds, is this requirement retained by the 3 rd interval RI-ISI program? The Attachment 1-1 and Attachment 1-2 tables do not identify any ASME Section XI Item Numbers making it impossible for the NRC staff to determine if this requirement was retained.

5. The original RI-ISI program stated that RI-ISI examination locations were selected such that >90% coverage is attainable. Was this requirement retained in the examination locations selected for the proposed program?

6. As a living program the original RI-ISI program required a review of the program on an ASME period basis. Is this requirement retained in the proposed RI-ISI program?

7. Risk informed applications must address external events as specified in Regulatory Guide 1.200 Revision 2. Please provide an assessment for how external events, including seismic events, at Diablo Canyon Power Plant affect the results of the risk impact analysis for the third ten-year interval inservice inspection program plan.