ML110270149
| ML110270149 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 02/14/2011 |
| From: | Sanders C Plant Licensing Branch 1 |
| To: | Heacock D Dominion Nuclear Connecticut |
| Sandeers, Carleen, NRR/DORL, 415-1603 | |
| References | |
| TAC ME44754, FOIA/PA-2011-0115 | |
| Download: ML110270149 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 14, 2011 Mr. David A. Heacock President and Chief Nuclear Officer Dominion Nuclear Connecticut, Inc.
Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711
SUBJECT:
MILLSTONE POWER STATION, UNIT NO.2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING EXAMINATION CRITERIA FOR WELD OVERLAYS (TAC NO. ME4475)
Dear Mr. Heacock:
By letter dated July 29, 2010, as supplemented by letter dated August 5, 2010 (Agencywide Document Access and Management System (ADAMS) Accession Nos. ML102580204 and ML102220527, respectively), Dominion Nuclear Connecticut, Inc. (DNC or the licensee),
submitted relief requests for the fourth 1 O-year inservice inspection (lSI) interval program at Millstone Power Station, Unit No.2 (MPS2). DNC requested the use of alternatives to certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),
Section XI requirements. Included in this request was Relief Request RR-04-07, which pertains to the lSI of Alloy 82/182 dissimilar metal piping welds and adjacent similar metal welds which have had a full structural weld overlay applied. The request is for the fourth 1 O-year lSI interval which began on April 1, 2010, and is scheduled to end on March 31, 2020. To complete its review, the Nuclear Regulatory Commission staff requests responses to the enclosed questions.
The other relief requests contained in the July 29, 2010, request are being reviewed separately.
The draft questions were sent to Mr. William Bartron, of your staff, to ensure that the questions were understandable, the regulatory basis for the questions was clear, and to determine if the information was previously docketed. On February 14, 2011, Mr. William Bartron agreed that you would provide a response by March 3, 2011.
If you have any questions regarding this matter, please contact me at 301-415-1603.
elY Sit,
,~
Carleen J nders, Project Manager Plant Lice Ing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-336
Enclosure:
As stated cc w/encl: Distribution via Listserv
OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR ADDITIONAL INFORMATION RELIEF REQUEST RR-04-07 PROPOSED ALTERNATIVE FOR EXAMINATION CRITERIA OF WELD OVERLAYS DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION, UNIT NO.2 DOCKET NUMBER 50-336 By letter dated July 29,2010, as supplemented by letter dated August 5,2010 (Agencywide Document Access and Management System (ADAMS) Accession Nos. ML102580204 and ML102220527, respectively), Dominion Nuclear Connecticut, Inc. (DNC or the licensee),
submitted relief requests for the fourth 1 O-year in service inspection (lSI) interval program at Millstone Power Station, Unit No.2 (MPS2). DNC requested the use of alternatives to certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),
Section XI requirements. Included in this request was Relief Request RR-04-07, which pertains to the lSI of Alloy 82/182 dissimilar metal piping welds and adjacent similar metal welds which have had a full structural weld overlay applied. The request is for the fourth 10-year lSI interval which began on April 1, 2010, and is scheduled to end on March 31, 2020.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided by the licensee in request RR-04-07 and has determined that the following additional information is needed in order to complete the review.
- 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.
- 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 growth,1 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 1 That exceed the acceptance standards of ASME Code,Section XI, IW8-3514 and are found to be acceptable for continued service through an analytical evaluation meeting the requirements of ASME Code,Section XI, IW8-3600 or a repair meeting the requirements of ASME,Section XI, IWA-4000 or the alternative requirements of an ASME Code Case.
Enclosure
- 2 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 Code 1 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.
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?
February 14, 2011 Mr. David A. Heacock President and Chief Nuclear Officer Dominion Nuclear Connecticut, Inc.
Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711
SUBJECT:
MILLSTONE POWER STATION, UNIT NO.2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING EXAMINATION CRITERIA FOR WELD OVERLAYS (TAC NO. ME4475)
Dear Mr. Heacock:
By letter dated July 29, 2010, as supplemented by letter dated August 5, 2010 (Agencywide Document Access and Management System (ADAMS) Accession Nos. ML102580204 and ML102220527, respectively), Dominion Nuclear Connecticut, Inc. (DNC or the licensee),
submitted relief requests for the fourth 10-year inservice inspection (lSI) interval program at Millstone Power Station, Unit No.2 (MPS2). DNC requested the use of alternatives to certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),
Section XI requirements. Included in this request was Relief Request RR-04-07, which pertains to the lSI of Alloy 82/182 dissimilar metal piping welds and adjacent similar metal welds which have had a full structural weld overlay applied. The request is for the fourth 10-year lSI interval which began on April 1, 2010, and is scheduled to end on March 31, 2020. To complete its review, the Nuclear Regulatory Commission staff requests responses to the enclosed questions.
The other relief requests contained in the July 29, 2010, request are being reviewed separately.
The draft questions were sent to Mr. William Bartron, of your staff, to ensure that the questions were understandable, the regulatory basis for the questions was clear, and to determine if the information was previously docketed. On February 14, 2011, Mr. William Bartron agreed that you would provide a response by March 3, 2011.
If you have any questions regarding this matter, please contact me at 301-415-1603.
Sincerely.
/raJ Carleen J. Sanders, Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-336
Enclosure:
As stated cc w/encl: Distribution via Listserv Distribution:
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