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 Union Electric Co
Donohew J N, NRR/DORL/LP4, 415-1307
References
TAC MD3434
Download: ML063520318 (7)

Text

January 18, 2007 Mr. Charles D. Naslund Senior 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 FOR SECOND 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 has determined 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 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. 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, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-483

Enclosure:

Safety Evaluation cc w/encl: See next page

ML063520318 OFFICE NRR/LPL4/PM NRR/LPL4/LA CVIB/BC OGC-NLO w/comments NRR/LPL4/BC NAME JDonohew LFeizollahi MMitchell JRund DTerao DATE 12/21/07 12/19/07 12/12/06 1/2/07 1/18/07 Callaway Plant, Unit 1 cc:

Professional Nuclear Consulting, Inc. Mr. Dan I. Bolef, President 19041 Raines Drive Kay Drey, Representative Derwood, MD 20855 Board of Directors Coalition for the Environment John ONeill, Esq. 6267 Delmar Boulevard Pillsbury Winthrop Shaw Pittman LLP University City, MO 63130 2300 N. Street, N.W.

Washington, D.C. 20037 Mr. Lee Fritz, Presiding Commissioner Callaway County Court House Mr. Keith A. Mills, Supervising Engineer 10 East Fifth Street Regional Regulatory Affairs/Safety Analysis Fulton, MO 65151 AmerenUE P.O. Box 620 Mr. David E. Shafer Fulton, MO 65251 Superintendent, Licensing Regulatory Affairs U.S. Nuclear Regulatory Commission AmerenUE Resident Inspector Office P.O. Box 66149, MC 470 8201 NRC Road St. Louis, MO 63166-6149 Steedman, MO 65077-1302 Manager, Regulatory Affairs Mr. Les H. Kanuckel AmerenUE Manager, Quality Assurance P.O. Box 620 AmerenUE Fulton, MO 65251 P.O. Box 620 Fulton, MO 65251 Mr. Keith G. Henke, Planner Division of Community and Public Health Missouri Public Service Commission Office of Emergency Coordination Governor Office Building 930 Wildwood P.O. Box 570 200 Madison Street Jefferson City, MO 65102 Jefferson City, MO 65102-0360 Certrec Corporation Regional Administrator, Region IV 4200 South Hulen, Suite 630 U.S. Nuclear Regulatory Commission Fort Worth, TX 76109 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Director, Missouri State Emergency Management Agency Mr. H. Floyd Gilzow P.O. Box 116 Deputy Director for Policy Jefferson City, MO 65102-0116 Missouri Department of Natural Resources P.O. Box 176 Jefferson City, MO 65102-0176 Mr. Rick A. Muench President and Chief Executive Officer Wolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KA 66839 June 2006

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SECOND 10-YEAR INTERVAL INSERVICE INSPECTION REQUEST FOR RELIEF NO. ISI-35 UNION ELECTRIC COMPANY CALLAWAY PLANT, UNIT 1 DOCKET NO. 50-483

1.0 INTRODUCTION

By application dated October 25, 2006 (Agencywide Documents Access and Management System 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.

2.0 REGULATORY REQUIREMENTS ISI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) 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 of Federal Regulation (10 CFR). 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 inservice examination of components and system pressure tests conducted 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 the requirements were imposed on the facility.

The licensee stated that the ASME Code of record for the Callaway Plant second 10-year interval inservice inspection program is the 1989 Edition with no Addenda of Section XI of the ASME Code.

3.0 NRC STAFF EVALUATION OF RR NO. ISI-35 3.1 Information provided by Licensee The following information was provided by the licensee in the attachment to its application dated October 25, 2006, on RR ISI-35.

ASME Code Components The 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 Requirements The applicable ASME Code requirements are the following:

• ASME Code,Section XI, IWC-2500-1, Category C-A, Item C1.10 requires volumetric examination of essentially 100 percent of the weld length.

• ASME Code Case N-460, Alternative Examination Coverage for Class 1 and Class 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 part geometry 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).

Licensees 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. The examination 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

requirements of ASME [Code] Section XI Appendix VIII. A copy of the examination report for the weld is attached.1 There 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 complete coverage would be needed to meet the ASME Code requirements. This would impose a considerable burden to Callaway Plant.

Licensees 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's Performance Demonstration Initiative [PDI] for Supplement 2 with a demonstrated best effort for single-side examination, are used from the accessible side of the weld.

3.2 NRC Staffs Evaluation The ASME Code,Section XI, requires a volumetric examination of essentially 100 percent of 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 licensee found 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 and flange 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 the flange 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 for the 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.

1 The licensees examination report for weld 2-EEJ01A-SEAM-1-W is not included in this safety evaluation and can be found in the licensees letter dated October 26, 2006.

The licensee obtained a composite coverage of 55 percent from the vessel side of weld 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.

3.3 Conclusion Based on the above evaluation, the NRC staff has reviewed the licensee's application for RR 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.

4.0 CONCLUSION

Therefore, based on the above evaluation for RR No. ISI-35, relief is granted by the Commission, 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