ML073111442

Correction to Authorization of Relief Request ISI-39 for the Second 10-Year Inservice Inspection Interval

ML073111442
Person / Time
Site:	Callaway
Issue date:	12/10/2007
From:	Donohew J NRC/NRR/ADRO/DORL/LPLIV
To:	Naslund C Union Electric Co
Donohew J N, NRR/DORL/LPL4, 415-1307
References
TAC MD3435
Download: ML073111442 (6)

Text

December 10, 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 - CORRECTION TO AUTHORIZATION OFRELIEF REQUEST ISI-39 FOR THE SECOND 10-YEAR INSERVICE INSPECTION INTERVAL (TAC NO. MD3435)

Dear Mr. Naslund:

In our letter to you dated September 17, 2007, the Nuclear Regulatory Commission (NRC)granted the relief in Relief Request (RR) ISI-39 for the second 10-year inservice inspection interval at the Callaway Plant, Unit 1 (Callaway). Union Electric Company (the licensee) submitted RR ISI-39 in its letter dated October 25, 2006 (ULNRC-05183).In Section 3.2, on RR ISI-39, of the safety evaluation (SE) enclosed with our letter datedSeptember 17, 2007, we documented the basis provided by the licensee to support the granting of RR ISI-39. Although the SE dated September 17, 2007, adequately documented the basis, we are modifying specific statements made in Section 3.2 of the SE to more precisely state the basis provided by the licensee for RR ISI-39. The attached revised pages 5 and 6 of the SE show the locations where modifications were made to the SE by the vertical lines on the right-hand-side of the two pages. Since the modifications did not change the conclusions made by the NRC in the SE, RR ISI-39 remains granted as of our letter dated September 17, 2007.Please replace pages 5 and 6 of the Callaway SE dated September 17, 2007, on RR ISI-39with the enclosed pages.Sincerely,/RA/Jack Donohew, Senior Project ManagerPlant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No. 50-483

Enclosure:

As stated cc w/encl: See next page

ML073111442NRR-106OFFICENRR/LPL4/PMNRR/LPL4/LADCI/CVIB/BCNRR/LPL4/BCNAMEJDonohew:spJBurkhardtMMitchellTHiltz DATE12/4/0712/6/0712/5/0712/10/07 ENCLOSUREREVISED PAGES 5 AND 6 OF SEPTEMBER 17, 2007,SAFETY EVALUATION FOR AUTHORIZATION OFCALLAWAY PLANT, UNIT 1, REQUEST FOR RELIEF ISI-39 Licensee's Basis for Relief Request (As stated in the licensee's application in the attachmentfor 10 CFR 50.55a Request Numbers ISI-36 (A.) through ISI-39 (D.))A.[Not for RR ISI-39]B.[Not for RR ISI-39]

C.[Not for RR ISI-39]D.[The licensee for the] Callaway Plant obtained 100% coverage for reflectorsparallel to the weld seam by a combination of radial scan paths (Star scans) and scans from within the nozzle bore (Bore scans). However, the proximity of the nozzle protrusion or boss to the [RPV] Outlet Nozzle-to-Shell welds limits the parallel scans from the vessel ID [inside diameter] (Tangential scans). Because of this, limited coverage of 58.6% was achieved [when] examining for transverse reflectors. Combined final ultrasonic examination coverage was estimated at 79.3%.The design configuration/restriction makes the [ASME] Code-required examinationcoverage requirements impractical. Plant modifications or the replacement of components designed to allow for complete coverage would be needed to meet the ASME Code requirements. This would impose a considerable burden to [the licensee of the] Callaway Plant.Licensee's Proposed Alternative Examination (As stated in the licensee's application)[The licensee for] Callaway proposes to accept the percent coverage obtained on thesubject examinations. The best-effort examination approach, in addition to the other considerations or actions described below, provides reasonable assurance of safety and/or structural integrity.

![Not for RR ISI-39]

l!The reactor vessel shell welds are constructed of low alloy steel [ ... Not for ISI-l39 ... ]. These materials have been shown to be resistant to stress corrosion lcracking in pressurized water environments. There is no [potential] degradationmechanism, other than fatigue, active in the subject welds that would cause weld failure.!VT-2 examinations performed in conjunction with system pressure testing eachrefueling, along with reactor coolant system leak rate limitations imposed by the plant's Technical Specifications, as well as containment atmospheric particulateradioactivity monitoring, provide additional assurance that a leak would be detected prior to any gross failure occurring.NRC Staff's EvaluationASME Code,Section XI requires volumetric examination of 100 percent as required inFigure IWB-2500-7(a) for the RPV Outlet Nozzle-to-Shell Welds numbered 2-RV-107-A, 2-RV-107-B, 2-RV-107-C, and 2-RV-107-D. The licensee was unable to meet the ASME Coderequirements due to the proximity of the nozzle protrusion or boss that limits the parallel scans from the RPV ID for tangential scans. For the licensee to meet the ASME Code requirements, modifications to, or the replacement of, the subject components would be required and would be major changes to the plant, which would place a burden on the licensee. Based on this, the NRC staff concludes that the ASME Code requirements are impractical.The licensee obtained 100 percent coverage for reflectors parallel to the weld seam by acombination of radial scan paths and scans from within the nozzle bore. Because of the configuration of the subject nozzles, the coverage was limited to 58.6 percent in examining for transverse reflectors. The licensee obtained an aggregate examination coverage of 79.3 percent for each of the subject nozzles. Therefore, the NRC staff determined that the lexaminations performed would have detected any significant patterns of degradation, if any had occurred. The NRC staff also determined that the volumetric and ASME Code VT-2 visual examinations during system walkdowns performed provided reasonable assurance of the structural integrity of RPV outlet nozzle-to-shell welds numbered 2-RV-107-A, 2-RV-107-B, 2-RV-107-C, and 2-RV-107-D.

4.0CONCLUSION

The NRC staff has reviewed the licensee's application dated October 25, 2006, which submittedthe licensee's RRs ISI-36, ISI-37, and ISI-39. RR ISI-37 was withdrawn in the licensee's letter dated June 26, 2007.Based on its evaluation in Section 3.1 of this SE, the NRC staff concludes for RR ISI-36 thatrelief is not required for Callaway because the licensee has met the ASME Code volumetric examination requirements for the RPV Lower Torus to Dollar Plate Weld 2-RV-102-151. Furthermore, based on its evaluation in Section 3.2 of this SE, the NRC staff concludes that theASME Code examination coverage requirements are impractical for the subject welds listed in RR ISI-39. Based on the coverages obtained, if significant service-induced degradation were occurring, there is reasonable assurance that evidence of it would be detected by the volumetric examinations that were performed. The volumetric examinations and VT-2 visual lexaminations during plant walkdowns performed provide reasonable assurance of structural integrity of the RPV Outlet Nozzle-to-Shell Welds numbered 2-RV-107-A, 2-RV-107-B, 2-RV-107-C, and 2-RV-107-D. The NRC staff has determined that granting relief pursuant to 10 CFR 50.55a(g)(6)(i) for RR ISI-39 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, pursuant to 10 CFR 50.55a(g)(6)(i), the NRC staff concludes that RR ISI-39 is granted for Callaway for the second 10-year ISI interval.

June 2007Callaway Plant, Unit 1 cc:John 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 P.O. Box 360 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 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 66839Certrec Corporation4200 South Hulen, Suite 422 Fort Worth, TX 76109Technical Services Branch ChiefFEMA Region VII 2323 Grand Boulevard, Suite 900 Kansas City, MO 64108-2670Mr. 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 Courthouse 10 East Fifth Street Fulton, MO 65251Mr. David E. Shafer, Superintendent, Licensing Regulatory Affairs AmerenUE P.O. Box 620 Fulton, MO 65251Manager, 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 65102Director, Missouri State Emergency Management Agency P.O. Box 116 Jefferson City, MO 65102-0116Mr. Scott Clardy, DirectorSection for Environmental Public Health P.O. Box 570 Jefferson City, MO 65102-0570