ML063520318

Request for Relief No. ISI-35 for Second 10-year Inservice Inspection Interval

ML063520318
Person / Time
Site:	Callaway
Issue date:	01/18/2007
From:	Terao D NRC/NRR/ADRO/DORL/LPLIV
To:	Naslund C D Union Electric Co
Donohew J N, NRR/DORL/LP4, 415-1307
References
TAC MD3434
Download: ML063520318 (7)

Text

January 18, 2007Mr. Charles D. NaslundSenior Vice President and Chief Nuclear Officer Union Electric Company Post Office Box 620 Fulton, MO 65251

SUBJECT:

CALLAWAY PLANT, UNIT 1 - REQUEST FOR RELIEF NO. ISI-35 FORSECOND 10-YEAR INSERVICE INSPECTION INTERVAL (TAC NO. MD3434)

Dear Mr. Naslund:

By letter dated October 25, 2006 (ULNRC-05183), the Union Electric Company (the licensee)requested relief from certain examination requirements of Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (i.e., the ASME Code) for the second 10-year inservice inspection (ISI) interval at the Callaway Plant (Callaway). Relief Requests (RRs)ISI-34, ISI-35, ISI-36, ISI-37, SI-38, ISI-39, ISI-40, and ISI-41 were submitted in that letter. This letter addresses RR ISI-35.Based on the attached safety evaluation, the Nuclear Regulatory Commission (NRC) staff hasdetermined that the ASME Code examination coverage requirements are impractical for the subject weld listed in RR ISI-35, and that the proposed inspection provides reasonable assurance of structural integrity. Therefore, granting relief, pursuant to paragraph 50.55a(g)(6)(i) of Title 10 of the Code of Federal Regulations, is authorized by law and will notendanger life or property or the common defense and security, and is otherwise in the public interest giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility. Therefore, the NRC staff grants the relief in RR ISI-35 for the second 10-year ISI interval at Callaway. All other ASME Code,Section XI, requirements for which relief was not specifically requested and approved in this relief request remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.Sincerely,/RA/David Terao, ChiefPlant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No. 50-483

Enclosure:

Safety Evaluation cc w/encl:See next page

ML063520318OFFICENRR/LPL4/PMNRR/LPL4/LACVIB/BCOGC-NLO w/commentsNRR/LPL4/BCNAMEJDonohewLFeizollahiMMitchellJRundDTerao DATE12/21/0712/19/0712/12/061/2/071/18/07 June 2006Callaway Plant, Unit 1 cc:Professional Nuclear Consulting, Inc.

19041 Raines Drive Derwood, MD 20855John O'Neill, Esq.Pillsbury Winthrop Shaw Pittman LLP 2300 N. Street, N.W.

Washington, D.C. 20037Mr. Keith A. Mills, Supervising EngineerRegional Regulatory Affairs/Safety Analysis AmerenUE P.O. Box 620 Fulton, MO 65251U.S. Nuclear Regulatory CommissionResident Inspector Office

8201 NRC Road Steedman, MO 65077-1302Mr. Les H. KanuckelManager, Quality Assurance AmerenUE P.O. Box 620 Fulton, MO 65251Missouri Public Service CommissionGovernor Office Building 200 Madison Street Jefferson City, MO 65102-0360Regional Administrator, Region IVU.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005Mr. H. Floyd GilzowDeputy Director for Policy Missouri Department of Natural Resources P.O. Box 176 Jefferson City, MO 65102-0176Mr. Rick A. MuenchPresident and Chief Executive Officer Wolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KA 66839Mr. Dan I. Bolef, PresidentKay Drey, Representative Board of Directors Coalition for the Environment 6267 Delmar Boulevard University City, MO 63130Mr. Lee Fritz, Presiding CommissionerCallaway County Court House 10 East Fifth Street Fulton, MO 65151Mr. David E. Shafer Superintendent, Licensing Regulatory Affairs AmerenUE P.O. Box 66149, MC 470 St. Louis, MO 63166-6149Manager, Regulatory AffairsAmerenUE P.O. Box 620 Fulton, MO 65251Mr. Keith G. Henke, PlannerDivision of Community and Public Health Office of Emergency Coordination 930 Wildwood P.O. Box 570 Jefferson City, MO 65102Certrec Corporation4200 South Hulen, Suite 630 Fort Worth, TX 76109Director, Missouri State Emergency Management Agency P.O. Box 116 Jefferson City, MO 65102-0116 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATIONSECOND 10-YEAR INTERVAL INSERVICE INSPECTIONREQUEST FOR RELIEF NO. ISI-35UNION ELECTRIC COMPANYCALLAWAY PLANT, UNIT 1DOCKET NO. 50-48

31.0INTRODUCTION

By application dated October 25, 2006 (Agencywide Documents Access and ManagementSystem Accession No. ML063050203), Union Electric Company (the licensee) requested relief from certain examination requirements of Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (i.e., the ASME Code) for the second 10-year inservice inspection (ISI) interval at the Callaway Plant (Callaway). Relief Requests (RRs) ISI-34, ISI-35, ISI-36, ISI-37, ISI-38, ISI-39, ISI-40, and ISI-41 were submitted in the letter. This safety evaluation addresses RR ISI-35.2.0REGULATORY REQUIREMENTSISI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASMECode) Class 1, 2, and 3 components is performed in accordance with Section XI of the ASME Code and applicable addenda as required by paragraph 50.55a(g) of Title 10 of the Code ofFederal Regulation (10 CFR). Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3components (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 inservice examination of components and system pressure testsconducted during the first 10-year 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) twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. However, if a licensee determines that conformance with these requirements is impractical, it may request relief from these specific requirements. Pursuant to 10 CFR 50.55a(g)(6)(i), the Commission may grant such relief and may impose 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 to the burden upon the licensee that could result if therequirements were imposed on the facility.The licensee stated that the ASME Code of record for the Callaway Plant second 10-yearinterval inservice inspection program is the 1989 Edition with no Addenda of Section XI of the ASME Code.3.0NRC STAFF EVALUATION OF RR NO. ISI-35 3.1Information provided by Licensee The following information was provided by the licensee in the attachment to its applicationdated October 25, 2006, on RR ISI-35.

ASME Code ComponentsThe component involved in the relief requests is the residual heat removal (RHR) Heat Exchanger A bonnet flange-to-channel weld 2-EEJ01A-SEAM-1-W.ASME Code RequirementsThe applicable ASME Code requirements are the following:*ASME Code,Section XI, IWC-2500-1, Category C-A, Item C1.10 requiresvolumetric examination of essentially 100 percent of the weld length.*ASME Code Case N-460, Alternative Examination Coverage for Class 1 andClass 2 Welds, as an alternative approved for use by the NRC in Regulatory Guide(RG) 1.147, Revision 14, "Inservice Inspection Code Case Acceptability, ASME Section XII, Division 1," states that a reduction in examination coverage due to partgeometry or interference for any ASME Code Class 1 or 2 weld is acceptable provided that the reduction is less than 10 percent (i.e., greater than 90-percent examination coverage is obtained).Licensee's Basis for Relief Request In the attachment to its application for RR ISI-35, the licensee stated the following:The stainless steel flange configuration caused the examination to be single-sided. Theexamination was further obstructed by flange bolting. An additional 45-degree full-vee shear wave examination and a 45-degree half-vee longitudinal wave examination were performed to address the flange side of the weld. Conservatively, however, no credit was taken for the flange side of the weld because single-sided examinations of austenitic welds have not been adequately demonstrated in accordance with the 1The licensee's examination report for weld 2-EEJ01A-SEAM-1-W is not included in this safety evaluationand can be found in the licensee's letter dated October 26, 2006.requirements of ASME [Code] Section XI Appendix VIII. A copy of the examinationreport for the weld is attached.

1There are currently no qualified single-side examination procedures that demonstrate equivalency to two-sided examination procedures on austenitic welds. Current technology is not capable of reliably detecting or sizing flaws on the far side of an austenitic weld for configurations common to US nuclear applications.Plant modifications or replacement with components designed to allow for completecoverage would be needed to meet the ASME Code requirements. This would impose a considerable burden to Callaway Plant.Licensee's Proposed Alternative Examination (As Stated)In an attachment to its application for RR ISI-35, the licensee stated the following:The best available techniques, similar to those qualified through the industry'sPerformance Demonstration Initiative [PDI] for Supplement 2 with a demonstrated best effort for single-side examination, are used from the accessible side of the weld.3.2NRC Staff's Evaluation The ASME Code,Section XI, requires a volumetric examination of essentially 100 percentof the weld length for the RHR Heat Exchanger A bonnet flange-to-channel weld No. 2-EEJ01A-SEAM-1-W. The volumetric examination by ultrasonic methodology of this weld was conducted to the extent practical by the licensee using personnel, equipment, and procedures qualified in accordance with ASME Code,Section XI, Appendix VIII. The licenseefound that during the ultrasonic examination of the subject weld essentially 100-percent coverage of the required examination weld length could not be obtained. The ASME Code examination was limited due to the stainless steel flange configuration andflange bolting. As a result, the licensee was only able to perform the examination from the vessel side of the weld. The licensee also performed an additional 45-degree full-vee shear wave examination and a 45-degree half-vee longitudinal wave examination to address theflange side of the weld. The licensee did not take credit for the flange examinations because the single-sided examinations of austenitic welds have not been adequately demonstrated and there are not examination procedures that demonstrate equivalency to two-sided examination procedures on austenitic welds at this time in accordance with the requirements of the ASME Code,Section XI, Appendix VIII. Therefore, the NRC staff determined that in order forthe licensee to obtain essentially 100-percent coverage of the required examination weld length, the RHR Heat Exchanger A bonnet flange-to-channel weld 2-EEJ01A-SEAM-1-W would have to be redesigned to allow greater access for scanning and would cause a burden on the

licensee. The licensee obtained a composite coverage of 55 percent from the vessel side ofweld No. 2-EEJ01A-SEAM-1-W. Therefore, the NRC staff has determined that the examinations performed would have detected significant patterns of degradation, if any had occurred. The NRC staff has also determined that the volumetric and ASME Code VT-2 visual examinations during system walkdowns performed provide reasonable assurance of structural integrity of the weld.3.3Conclusion Based on the above evaluation, the NRC staff has reviewed the licensee's application forRR ISI-35 and concludes that the ASME Code examination coverage requirements are impractical for RHR Heat Exchanger A bonnet flange-to-channel weld 2-EEJ01A-SEAM-1-W for Callaway. Furthermore, based on the coverages obtained, if significant service-induced degradation were occurring, the NRC staff also concludes that there is reasonable assurance that evidence of it would have been detected by the examinations that were performed and that the volumetric examinations performed and VT-2 visual examinations during plant walkdowns provide reasonable assurance of structural integrity of weld 2-EEJ01A-SEAM-1-W.

4.0CONCLUSION

Therefore, based on the above evaluation for RR No. ISI-35, relief is granted by theCommission, pursuant to 10 CFR 50.55a(g)(6)(i), on the basis that the ASME Code-required examination is impractical, for the second 10-year ISI interval for Callaway and that the proposed inspection provides reasonable assurance of structural integrity. The NRC staff has also determined that granting relief pursuant to 10 CFR 50.55a(g)(6)(i) for RR No. ISI-35 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 to the burden upon the licensee that could result if the requirements were imposed on the facility. All other ASME Code,Section XI, requirements for which relief was not specifically requested and approved in the subject requests for relief remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.Principal Contributor: Tom McLellan Date: January 18, 2007