ML032470041

Relief Request No. A-9 Inservice Inspection of Reactor Head Closure Studs

ML032470041
Person / Time
Site:	Comanche Peak
Issue date:	09/03/2003
From:	Thadani M NRC/NRR/DLPM/LPD4
To:	Terry C TXU Energy
Thadani M, NRR/DLPM, 415-1476
References
TAC MB7946
Download: ML032470041 (7)

Text

September 3, 2003 Mr. C. Lance Terry Senior Vice President &

Principal Nuclear Officer TXU Energy Attn: Regulatory Affairs Department P. O. Box 1002 Glen Rose, TX 76043

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION, UNIT 2 - RELIEF REQUEST NO. A-9, FROM THE REQUIREMENTS OF THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS BOILER AND PRESSURE VESSEL CODE, SECTION XI, CONCERNING SECOND 10-YEAR INSERVICE INSPECTION INTERVAL (TAC NO. MB7946)

Dear Mr. Terry:

By letter dated March 6, 2003, as supplemented by letter dated July 1, 2003, TXU Energy (the licensee) submitted Relief Request A-9 for Comanche Peak Steam Electric Station (CPSES),

Unit 2. Pursuant to Title 10 of the Code of Federal Regulations (10 CFR), Section 50.55a(g)(4)(iv) the licensee requested approval of a relief for the second 10-year inservice inspection (ISI) interval from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code), 1986 Edition with no Addenda, Table IWB-2500-1, Category B-G-1. In addition, the licensee requested approval of an alternative to use 1998 Edition with 1999 Addenda and 2000 Addenda of the ASME Code. The July 1, 2003, supplemental letter removed a reference to Code Case N-307-3.

The Nuclear Regulatory Commission Staff has reviewed the licensees request and concluded that, because the ASME Code, 1998 Edition, 2000 Addenda, has been incorporated by reference in 10 CFR 50.55a(b), the alternative proposed by the licensee provides an acceptable level of quality and safety. Therefore, the licensees request to use ASME Code, 1998 Edition, 2000 Addenda, Table IWB-2500-1, Category B-G-1, reactor vessel head closure studs, washers, bushings, and nuts, is authorized for the second 10-year ISI interval for CPSES,

Mr. C. Lance Terry Unit 2. All other requirements of the ASME Code,Section III and XI, for which relief has not been specifically requested, remain applicable; including third party review by the Authorized Nuclear Inservice Inspector.

Sincerely,

/RA/

Robert A. Gramm, Chief, Section 1 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No.: 50-446 cc: See next page

ML032470041 Subject to changes noted NRR-028 OFFICE PDIV-1/PM PDIV-1/LA EMCB/SC OGC PDIV-1/SC NAME MThadani:sab DJohnson SCoffin* CMarco** RGramm DATE 9/03/03 9/03/03 08/11/03 9/03/03 9/03/03 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SECOND 10-YEAR INSERVICE INSPECTION PROGRAM INTERVAL REQUEST FOR RELIEF TXU GENERATION COMPANY LP COMANCHE PEAK STEAM ELECTRIC STATION, UNIT 2 DOCKET NO. 50-446

1.0 INTRODUCTION

By letter dated March 6, 2003, as supplemented by letter dated July 1, 2003, TXU Energy (the licensee) submitted Relief Request A-9 for Comanche Peak Steam Electric Station (CPSES),

Unit 2. Pursuant to Title 10 of the Code of Federal Regulations (10 CFR), Section 50.55a(g)(4)(iv) the licensee requested approval of a relief for the second 10-year inservice inspection (ISI) interval from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code), 1986 Edition with no Addenda, Table IWB-2500-1, Category B-G-1. In addition, the licensee requested approval of an alternative to use 1998 Edition with 1999 Addenda and 2000 Addenda of the ASME Code. The July 1, 2003, supplemental letter removed a reference to Code Case N-307-3.

2.0 REGULATORY REQUIREMENTS ISI of the ASME Code, Class 1, 2, and 3 components is to be performed in accordance with Section XI of the ASME Code, and applicable addenda, as required by 10 CFR 50.55a(g),

except where specific relief has been granted by the Commission, pursuant to 10 CFR 50.55a(g)(6)(i). Section 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if the applicant demonstrates that:

(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.

Pursuant to 10 CFR 50.55a(g)(4), ASME Code, Class 1, 2, and 3 components (including supports), shall meet the requirements, except the design and access provisions and the pre-service examination requirements, set forth in the ASME Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that ISI examination of components and system pressure tests conducted during the first 10-year ISI interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code, incorporated by reference in 10 CFR 50.55a(b), 12 months prior to the start of the 120-month interval, subject to the

limitations and modifications listed therein. The code of record for the CPSES, Unit 2, second 10-year ISI interval is the 1986 Edition of the ASME Code.

3.0 TECHNICAL EVALUATION

REQUEST FOR RELIEF NO. A-9 Code Requirement for Which Relief is Requested:

The 1986 Edition of the ASME Code,Section XI, Table IWB-2500-1, Category B-G-1, requires the following:

(1) Examinations of the reactor closure head studs include both a surface and volumetric method when removed.

(2) Examination Figure IWB-2500-12 for Item No. B6.30, pertaining to the reactor closure head studs, requires that the examination volume be defined as the full volume of the load-bearing portion of the studs.

(3) Item No. B6.10 requires a surface examination for closure head nuts.

System/Component(s) for Which Relief is Requested:

ASME Class 1, Reactor Pressure Vessel Closure Head Nuts and Studs. The subject items are depicted as TBX-1-1400-37 through 54 in the CPSES, Unit 2, ISI Program Plan.

Licensees Proposed Alternative Examination (As stated):

TXU Energy requests to use 1998 Edition, 1999 Addenda and 2000 Addenda, of the ASME Section XI, Table IWB -2500-1 for category B-G-1, Items B6.10, B6.20, B6.30, B6.40, and B6.50, for the reactor vessel head pressure retaining bolting and all associated requirements, if any, as allowed by 10 CFR 50.55a(g)(4)(iv).

Licensees Basis for Requesting Relief (As stated):

The NRC staff incorporated these changes by reference in 10 CFR 50.55a(b). The changes to Table IWB-2500-1 examination criteria do not affect other parts of the Code.

Additionally, the volumetric examinations will be performed with procedures and personnel qualified in accordance with ASME Section XI, Appendix VIII, as required by 10 CFR 50.55a(g)(6)(ii)(C). Therefore, the proposed change will result in an acceptable level of quality and safety.

Staff Evaluation:

The licensee proposes to use the ASME Code, 1998 Edition, 2000 Addenda, of the ASME Section XI, Table IWB-2500-1, for category B-G-1, reactor vessel closure studs and nuts. The ASME Code, 1998 Edition, 2000 Addenda, has been incorporated by reference in 10 CFR 50.55a(b). Additionally, the licensee proposed that the volumetric

examinations will be performed with procedures and personnel qualified in accordance with ASME Section XI, Appendix VIII, as required by 10 CFR 50.55a(g)(6)(ii)(C).

The 1986 Edition, Table IWB-2500-1, Category B-G-1, Item B6.10, closure head nuts, requires a surface examination, where as the later Editions and Addenda require a VT-1 visual examination. For Item B6.30, the 1986 Edition requires surface and volumetric examinations of the closure studs when removed, where as the later Edition and Addenda requires surface or volumetric examination. In addition, for Item B6.30, the 1986 Edition defines the examination volume as the full volume, where as the later Edition and Addenda defines it as 0.25-inch from the threads which are stress risers and preferred sites for crack initiation. For Items B6.20 (Closure Studs - volumetric in place), B6.40 (Threads in Flange - volumetric), and B6.50 (Closure Washers, Bushings -

surface examinations) there is no change in the examination method. In the later Edition and Addenda, the examinations can be deferred to the end of the interval.

The staff has reviewed the changes in the 1998 Edition, 2000 Addenda, which were incorporated by reference in 10 CFR 50.55a(b) and finds that the licensees proposed alternative provides reasonable assurance of quality and safety.

4.0 CONCLUSION

Based on the above evaluation, the NRC staff concludes that, because the ASME Code, 1998 Edition, 2000 Addenda, has been incorporated by reference in 10 CFR 50.55a(b), the alternative proposed by the licensee provides an acceptable level of quality and safety.

Therefore, the licensees request to use ASME Code,Section XI, 1998 Edition, 2000 Addenda, Table IWB-2500-1, Category B-G-1, reactor vessel head closure studs, washers, bushings, and nuts, may be authorized for the second 10-year ISI interval for CPSES, Unit 2. All other requirements of the ASME Code,Section III and XI, for which relief has not been specifically requested remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.

Principal Contributor: T. K. McLellan Date: September 3, 2003

Comanche Peak Steam Electric Station cc:

Mr. Brian Almon Senior Resident Inspector Public Utility Commission U.S. Nuclear Regulatory Commission William B. Travis Building P. O. Box 2159 P. O. Box 13326 Glen Rose, TX 76403-2159 1701 North Congress Avenue Austin, TX 78701-3326 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Ms. Susan M. Jablonski 611 Ryan Plaza Drive, Suite 400 Office of Permitting, Remediation Arlington, TX 76011 and Registration Texas Commission on Environmental Mr. Roger D. Walker Quality Regulatory Affairs Manager MC-122 TXU Generation Company LP P. O. Box 13087 P. O. Box 1002 Austin, TX 78711-3087 Glen Rose, TX 76043 Terry Parks, Chief Inspector George L. Edgar, Esq. Texas Department of Licensing Morgan Lewis and Regulation 1111 Pennsylvania Avenue, NW Boiler Program Washington, DC 20004 P. O. Box 12157 Austin, TX 78711 County Judge P. O. Box 851 Glen Rose, TX 76043 Environmental and Natural Resources Policy Director Office of the Governor P. O. Box 12428 Austin, TX 78711-3189 Mr. Richard A. Ratliff, Chief Bureau of Radiation Control Texas Department of Health 1100 West 49th Street Austin, TX 78756-3189 March 2003