ML110610207
| ML110610207 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 03/01/2011 |
| From: | Price J Dominion Nuclear Connecticut |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 11-097, FOIA/PA-2011-0115 | |
| Download: ML110610207 (5) | |
Text
Dominion Energy Kewaunee, Inc.
5000 Dominion Boulevard, Glen Allen, VA 23060 March 1.. 2011 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Serial No.
NSSLIWDC Docket No.
License No.11-097 RO 50-336 DPR-65 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 2 RELIEF REQUEST RR-04-07: RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED ALTERNATIVE FOR EXAMINATION CRITERIA OF WELD OVERLAYS As part of the inservice inspection (lSI) program, Dominion Nuclear Connecticut, Inc. (DNC) submitted a letter dated July 29, 2010 and a supplemental letter dated August 5,2010 requesting approval of Relief Request RR-04-07. Relief Request RR-04-07 is related to the inservice inspection (lSI) of Alloy 82/182 dissimilar metal piping welds and adjacent similar metal welds which have had a full structural weld overlay applied.
In a letter dated February 14, 2011, the Nuclear Regulatory Commission (NRC) transmitted a request for additional information (RAI) related to this relief request.
During a February 14, 2011 conference call between DNC and the NRC, it was agreed DNC would respond to the RAI by March 3, 2011. provides DNC's response to the NRC RAI addressing questions 1 and 2.
If you have any questions regarding this submittal, please contact Wanda Craft at (804) 273-4687.
Sincerely,
Serial No.11-097 Docket No. 50-336 RR-04-07 Response to RAI Page 2 of 2
Attachment:
- 1. Relief Request RR-04-07: Response to Request for Additional Information Regarding Proposed Alternative for Examination Criteria of Weld Overlays Commitments made in this letter: None cc:
U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1415 C. J. Sanders Project Manager - Millstone Power Station U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 0-883 Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station
Serial No.11-097 Docket No. 50-336 ATTACHMENT 1 RELIEF REQUEST RR-04-07: RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED ALTERNATIVE FOR EXAMINATION CRITERIA OF WELD OVERLAYS DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 2
Serial No.11-097 Docket No. 50-336 RR-04-07 Response to RAI, Page 1 of 2 Question 1 Relief Request RR-04-07 states that the subject welds and weld overlays are also the subject of Relief Request RR-89-61, Revision 2, which was authorized for use by the NRC on October 15, 2009 (ADAMS Accession No. ML092870739).
The welds and weld overlays listed as Component Nos. 11, 12, and 13 in RR-04-07 do not correspond to any of the welds or weld overlays listed in RR-89-61.
Please verify the welds and weld overlays listed as Component Nos. 11, 12, and 13 are welds and weld overlays subject to RR-89-61, Revision 2.
ONe Response The welds listed as Component Nos. 11, 12, and 13 are welds subject to RR-89-61, Revision 2.
However, in Relief Request RR-04-07, the weld numbers were incorrectly identified with a BCD designation.
The correct weld designation for these welds is BPD. The correct weld numbers are as follows:
Component No. 11 - Weld No. BPD-C-1017 and the adjacent safe-end to pipe weld BPD-C-1019 Component No. 12 - Weld No. BPD-C-2001 and the adjacent safe-end to pipe weld BPD-C-2003 Component No. 13 - Weld No. BPD-C-3000 and the adjacent safe-end to pipe weld BPD-C-3002 Question 2 Full structural weld overlays are designed to prevent new flaws from occurring and to prevent the growth of existing flaws.
Therefore, if examination of a weld mitigated with a full structural weld overlay detects new flaws or flaw growth1, the weld overlay likely did not perform as designed and the NRC will need to assess the licensee's actions to address this situation.
In order to make this assessment, NRC staff needs specific information detailing new flaws or flaw growth. Although the NRC staff prefers to have this information prior to the plant's re-entry into Mode 4, these conditions will have been evaluated by the licensee in accordance with the ASME Code1 as acceptable for continued service, therefore the NRC staff does not need to complete its assessment prior to the plants re-entry into Mode 4 nor place any restrictions on plant operation.
1 That exceed the acceptance standards of ASME Code,Section XI, IWB-3514 and are found to be acceptable for continued service through an analytical evaluation meeting the requirements of ASME Code,Section XI, IWB-3600 or a repair meeting the requirements ofASME,Section XI, IWA-4000 or the alternative requirements of an ASME Code Case.
Serial No.11-097 Docket No. 50-336 RR-04-07 Response to RAI, Page 2 of 2 The NRC staff's focus is on any adverse effects of the new flaws or flaw growth over the full service life of the mitigated weld.
Please clarify your plans for: (a) evaluating new flaws or flaw growth on the subject welds of Request IR-4-07, and (b) submitting reports on such evaluations to the NRC prior to the welds being placed in service in Modes other than 5 and 6?
ONe Response (a) Upon completion of the examination of a mitigated weld addressed in Relief Request RR-04-07, the results will be evaluated relative to the baseline examination to determine if there are new flaws, or any changes that indicate flaw growth in existing flaws..
The acceptance criteria for evaluation is ASME Code,Section XI, IWB 3514.
(b) The Millstone Power Station NRC Project Manager will be notified of new flaws or growth of existing flaws which are identified by the weld examinations.
Preliminary flaw characterization and evaluation results will be made available to the NRC staff prior to the identified welds being placed in service in Modes other than 5 and 6.
Additional detail associated with any new flaws or flaw growth will be included in the routine Owner's Activity Report (OAR-1) and will be submitted following a refueling outage in which such flaws or flaw growths have been identified.