ML101480011

Correction Letter for Relief 09-MN-007 Regarding Reactor Vessel (Rv) Cold Leg Nozzle-to-Safe End and Safe End-to-Pipe Weld Examinations During the Third 10-Year Inservice Inspection (ISI) Interval

ML101480011
Person / Time
Site:	McGuire
Issue date:	06/07/2010
From:	Jacqueline Thompson Plant Licensing Branch II
To:	Repko R Duke Energy Carolinas
Thompson Jon, NRR/DORL/LPL 2-1, 415-1119
References
TAC ME2383
Download: ML101480011 (5)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 June 7, 2010 Mr. Regis 1. Repko Vice President McGuire Nuclear Station Duke Energy Carolinas, LLC 12700 Hagers Ferry Road Huntersville, NC 28078 SUB~IECT: MCGUIRE NUCLEAR STATION, UNIT 1 - CORRECTION LEDER FOR RELIEF 09-MN-007 REGARDING REACTOR VESSEL (RV) COLD LEG NOZZLE-TO-SAFE END AND SAFE END-TO-PIPE WELD EXAMINATIONS DURING THE THIRD 10-YEAR INSERVICE INSPECTION (lSI) INTERVAL (TAC NO. ME2383)

Dear Mr. Repko:

By letter dated September 15, 2009, as supplemented by letter dated February 9, 2010, Duke Energy Carolinas LLC (the licensee), submitted relief request (RR) 09-MN-007 for McGuire Nuclear Station, Unit 1 (McGuire 1), related to the third 10-year lSI interval pertaining to utilization of an alternate depth-sizing criteria during the ultrasonic examination of the RV cold leg nozzle-to-safe end (dissimilar metal) and safe end-to-pipe (similar metal) welds during the next scheduled refueling outage (March 2010). The Nuclear Regulatory Commission (NRC) staff evaluated the information provided in the licensee's relief request and concluded that the proposed alternative provides an acceptable level of quality and safety.

By letter dated March 4, 2010, the NRC staff authorized the implementation of Relief 09-MN-007 for the McGuire 1 third 1O-year lSI interval, pursuant to Section 50.55a(a)(3)(i) of Title 10 of the Code of Federal Regulations.

Subsequent to the issuance, Mr. Vu of your staff informed the NRC staff of errors in the cover letter and on Pages 1 and 5 of the safety evaluation (SE). The errors relate to the need to replace all references to "core flood nozzle-to-safe end (dissimilar metal) welds" with references to "cold leg nozzle-to-safe end (dissimilar metal) and safe end-to-pipe (similar metal) welds."

There is also a need to reference your letter dated February 9, 2010, which was submitted in association with this RR. Corrected SE pages 1 and 5 are enclosed with bars in the right margin indicating the lines with the changes.

R. Repko -2 The NRC regrets any inconvenience that this may have caused. If you have any questions regarding this matter, please contact me at (301) 415-1447.

Sincerely, Jon H. Thompson, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-369

Enclosure:

Corrected SE Pages 1 and 5 cc w/encl: Distribution via Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THIRD 10-YEAR INTERVAL INSERVICE INSPECTION RELIEF NO. 09-MN-007 DUKE ENERGY CAROLINAS, LLC MCGUIRE NUCLEAR STATION, UNIT 1 DOCKET NO. 50-369

1.0 INTRODUCTION

By letter dated September 15, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML092720862), as supplemented by letter dated February 9, 2010 (ADAMS Accession No. ML100490753), Duke Energy Carolinas, LLC (the licensee), submitted Request for Relief 09-MN-007 for McGuire Nuclear Station, Unit 1 (McGuire 1), related to the third 10-year Inservice Inspection (lSI) interval pertaining to utilization of an alternate depth-sizing criteria during the ultrasonic examination of the reactor vessel cold leg nozzle-to safe end (dissimilar metal) and safe end-to-pipe (similar metal) welds during the next scheduled refueling outage (March 2010). The third 10-year lSI interval for McGuire 1 ends on December 1, 2011. The licensee requested approval of a proposed alternative to the American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code (Code),

requirements for flaw depth-sizing criteria. The Code requires that the root mean square error (RMSE) for flaw depths estimated by Ultrasonic Testing (UT) shall not exceed 0.125 inch; and states that the RMSE of the flaw depths estimated by ultrasonics, as compared to true depths, is less than the 0.125-inch RMSE. The Code of Record for McGuire 1 is the 1998 Edition through the 2000 Addenda of the ASME Code.

2.0 REGULATORY EVALUATION

Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Section 50.55a(g) specifies that lSI of nuclear power plant components shall be performed in accordance with the requirements of ASME Code,Section XI, except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i). As stated in 10 CFR 50.55a(g)(6)(i) the Commission may grant such relief and may impose such alternative requirements as it determines is authorized by law and will not endanger life or property or the common defense and security and is otherwise in the public interest, giving due consideration of the burden upon the licensee. As stated in 10 CFR 50.55a(a)(3), alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if (i) the proposed alternatives would provide an acceptable level of quality and safety, or (ii) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. As stated in 10 CFR 50.55a(g)(5)(iii) if the licensee has determined that Enclosure Corrected by letter dated June 7, 2010

-5 inch) will be added to the measured through-wall extent. This total flaw depth will then be assessed against the applicable acceptance criteria specified in Section IWB-3600 of the ASME Code for flaw evaluation. Additionally, the licensee proposes that, if the examination vendor demonstrates an improved depth sizing RMSE prior to the examination, the excess of the improved RMSE over the 0.125-inch RMSE requirement, if any, will be added to the measured value for flaw evaluation with applicable acceptance criteria specified in Section IWB-3600 of the ASME Code.

The NRC staff finds that compliance with the ASME Code-required RMSE value is not feasible at this time. Also, the NRC staff finds that the licensee's proposed alternative of adding the difference between the ASME Code-required RMSE and the demonstrated RMSE to the measured through-wall extent, in addition to the use of the acceptance standards specified in Section IWB-3600 of the ASME Code, provides an acceptable level of quality and safety.

The NRC staff has reviewed the licensee's submittal and determined that Relief Request 09-MN-007 will provide an acceptable level of quality and safety for the operation of the subject reactor vessel cold leg nozzles. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the NRC staff authorizes the use of Relief Request 09-MN-007 for the third 1O-year lSI interval at McGuire 1.

5.0 CONCLUSION

The licensee's proposal of adding the difference between the ASME Code-required RMSE and the demonstrated RMSE to the measured through-wall extent, in addition to the use of the acceptance standards specified in Section IWB-3600 of the ASME Code, provides an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the proposed alternative is authorized for the remainder of the third 10-year lSI interval for McGuire 1, which ends on December 1,2011. All other ASME Code,Section XI, requirements for which relief was not specifically requested and authorized herein by the NRC staff remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.

Principal Contributors: M. Audrain, NRR C. Nove, NRR Date: March 4, 2010 Corrected by letter dated June 7, 2010 I

R. Repko -2 The NRC regrets any inconvenience that this may have caused. If you have any questions regarding this matter, please contact me at (301) 415-1447.

Sincerely, IRA!

Jon H. Thompson, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-369

Enclosure:

Corrected SE Pages 1 and 5 cc w/encl: Distribution via Listserv DISTRIBUTION:

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