ML080860589

Response to Request for Additional Information on the Use of Alternative Examination Technique of Select Class 1 Piping Dissimilar Metal Welds (Request No. RR-89-64)

ML080860589
Person / Time
Site:	Millstone
Issue date:	03/26/2008
From:	Hartz L Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
08-0047A, TAC MD6911
Download: ML080860589 (4)

Text

Dominion Nuclear Connecticut, Inc.

'000 Dominion Boulevard, Glen Allen, Virginia 21060

\X'd, Address: www.dom.com March 26, 2008 U. S. Nuclear Regulatory Commission Serial No.: 08-0047A Attention: Document Control Desk NSSLIMAE R1 One White Flint North Docket No.: 50-336 11555 Rockville Pike License No.: DPR-65 Rockville, Maryland 20852-2738 DOMINION NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION UNIT 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION ON THE USE OF ALTERNATIVE EXAMINATION TECHNIQUE OF SELECT CLASS 1 PIPING DISSIMILAR METAL WELDS (REQUEST NO. RR-89-64, TAC NO. MD6911)

In a letter dated September 27, 2007, Dominion Nuclear Connecticut, Inc. (DNC) submitted Millstone Power Station Unit 2 Alternative Request RR-89-64. DNC requested Nuclear Regulatory Commission (NRC) approval of an alternative to use a limited, one-sided ultrasonic examination technique for eight 36-inch outside diameter welds. These welds are located on the reactor coolant system cold leg and are dissimilar metal welds with cast austenitic stainless steel safe ends that are welded with Alloy 82/182 material.

On January 30, 2008, the NRC issued a request for additional information (RAI) containing nine questions related to the DNC request. DNC letter dated February 18, 2008 provided a response to the questions. Subsequently, the NRC issued an additional question on February 28, 2008. A response to the additional question is provided in the attachment to this letter. The response is consistent with the information discussed in a telephone conference with the NRC staff on March 10, 2008.

Should you have further questions, please contact Margaret Earle at (804) 273-2768.

Sincerely,

>(Y;J-({7f Leslie Hartz { /

Vice President - Nuclear Support Services Commitments in this letter: None Attachment

Serial No. 08-0047A Docket No. 50-336 Response to RAI on RR-89-64 Page 2 of 2 cc: U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1415 Mr. J. D. Hughey 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. 08-0047A Docket No. 50-336 ATTACHMENT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION ON THE USE OF ALTERNATIVE EXAMINATION TECHNIQUE OF SELECT CLASS 1 PIPING DISSIMILAR METAL WELDS (REQUEST NO. RR-89-64, TAC NO. MD6911)

MILLSTONE POWER STATION UNIT 2 DOMINION NUCLEAR CONNECTICUT, INC.

Serial No. 08-0047A Docket No. 50-336 Response to RAI on RR-89-64 Attachment Page 1 of 1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION ON THE USE OF ALTERNATIVE EXAMINATION TECHNIQUE OF SELECT CLASS 1 PIPING DISSIMILAR METAL WELDS (REQUEST NO. RR-89-64, TAC NO. MD6911)

NRC QUESTION:

In EPRI report IR-2007-277, EPRI provided estimated coverage for the 7 welds in Alternative Request RR-89-64 but not weld P-8-C-1. Please provide the estimated ultrasonic examination coverage for weld P-8-C-1.

RESPONSE

The EPRI report does not contain field data for the specific nozzle P-8-C-1. Accordingly, the report does not include an estimate of the examination coverage expected to be obtained in 2R18 for the P-8-C-1 nozzle, or provide its photograph and detailed sketches of the weld profiles.

DNC performed a profile observation of the P-8-C-1 nozzle welds during refueling outage 2R17 in the fall of 2006 in planning for the use of this alternative examination. This profile observation was performed subsequent to commissioning of the EPRI report. Based upon the profile observation in 2R17, the component information of Table 3-1 in the EPRI report remains applicable to the P-8-C-1 nozzle. The design and weld profiles of the four inlet nozzles are comparable and Table 3-1 of the EPRI report that provides component information is also applicable to the P-8-C-1 nozzle. The assessment of estimated coverage shown by the report on the other three inlet nozzles P-4-C-1, P-13-C-1 and P-17-C-1 are representative of the capability of the examination technique to be used on the P-8-C-1 nozzle. DNC reviewed the available weld profiles of the P-8-C-1 nozzle and determined that coverage shown for the P-4-C-1 nozzle in the EPRI report can be applied as an estimate for the P-8-C-1 nozzle coverage assessment. Additionally, the observations and recommendations of Section 3.3 of the EPRI report remain applicable to the P-8-C-1 nozzle.