ML071730352

Request for Additional Information for the Review of the Wolf Creek Generating Station, Unit 1, License Renewal Application

ML071730352
Person / Time
Site:	Wolf Creek
Issue date:	06/22/2007
From:	Veronica Rodriguez NRC/NRR/ADRO/DLR/RLRB
To:	Garrett T Wolf Creek
Rodriguez V NRR/DLR/RLRB 415-3703
References
Download: ML071730352 (6)

Text

June 22, 2007Mr. Terry J. GarrettVice President Engineering Wolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KS 66839

SUBJECT:

REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THEWOLF CREEK GENERATING STATION, UNIT 1, LICENSE RENEWAL APPLICATION

Dear Mr. Garrett:

By letter dated September 27, 2006, Wolf Creek Nuclear Operating Corporation submitted anapplication pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Part 54, to renewthe operating license for Wolf Creek Generating Station, Unit 1, for review by the U.S. Nuclear Regulatory Commission (NRC or the staff). The staff is reviewing the information contained in the license renewal application and has identified, in the enclosure, areas where additional information is needed to complete the review.These requests for additional information were discussed with Lorrie Bell, and a mutuallyagreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me at 301-415-3703 or e-mail VMR1@nrc.gov

.Sincerely,/RA/Verónica M. Rodríguez, Project ManagerLicense Renewal Branch B Division of License Renewal Office of Nuclear Reactor RegulationDocket No. 50-482

Enclosure:

Requests for Additional Informationcc w/encl: See next page

ML071730352OFFICEPM:RLRB:DLRLA:DLRBC:RLRB:DLRNAMEVRodriguezYEdmonds RAuluck DATE06/22/0706/22/0706/22/07 EnclosureWOLF CREEK GENERATING STATION, UNIT 1LICENSE RENEWAL APPLICATIONREQUESTS FOR ADDITIONAL INFORMATION (RAI)Metal Fatigue AnalysisDuring the Wolf Creek Generating Station (WCGS) onsite audits the staff reviewed theapplicant's license renewal basis document which states that the cumulative usage factors for 24 locations were evaluated using the transfer function method in FatiguePro. FatiguePro performs stresses calculations as a function of the time-varying mechanical and thermal boundary conditions. The transfer function (i.e., green function) quantifies component stresses due to temperaturechange, pressure variation, and external mechanical loading change. The transfer function method correlates time-dependent behavior of a component in terms of input and output.The staff reviewed the FatiguePro user's manual for the transfer function input and calculatedoutput. The staff could not determine if the program appropriately implemented the transfer function methodology to meet the requirements of ASME Code Section III. The staff requestedthat the applicant demonstrate the validity of its input and output by providing the benchmarking results for pressure, temperature, and moment loadings. In a letter dated June 7, 2007, WCGS stated that the developer of the FatiguePro, StructuralIntegrity Associates (SIA), has never benchmarked the transfer functions to an independent standard. The applicant also states that 1D virtual stress was used for its calculation, which was designed to bound the actual stress intensity ranges for all fatigue significant transients.

Furthermore, the applicant also states that this type of stress value does not have a name in the professional literature. Based on the discussion with the applicant, the staff indicated that this response requires clarification. RAI 4.3-1 In its response to audit question TLAAA025 dated June 7, 2007, the applicant stated that thetransfer function report defines a 1D virtual stress value that is designed to bound the actual stress intensity ranges for all fatigue significant transients and this type of stress value does not have a name in the professional literature. (1) Since it cannot be found in the professional literature, the staff requests that theapplicant describe in detail how the 1D virtual stress is derived.(2) The staff requests that the applicant demonstrate how the virtual stress bounds theactual stress intensity ranges for any thermal transient. Show that the stress difference between any two thermal transients is also conservative since the fatigue evaluation is based on stress difference of two events. RAI 4.3-2 In audit question TLAAA025, the staff requested that the applicant explain how to determine thestress transfer function for pressure and moments by using WCAP-14137 Table E.2-1 as an example to demonstrate the following: S(pr) = 3.71 (psi/psi pressure)

S(momxz) = 9.4 (psi/applied in-kip bending moment)

S(momy) = 0.0 (psi/applied in-kip torsion)In its response dated June 7, 2007, the applicant stated that this information was derived from a proprietary stress report rather than computed according to some formula. The staff notes that WCAP-14137 Table E.2-1 lists a 14 inch schedule 160 pipe stress transferfunction. For a standard 14 inch schedule 160 pipe, stress can be calculated with a well known pressure stress equation, bending stress equation, and torsion shear stress equation as shown below:For axial stress: S(pr) = pRi 2 / (Ro 2 - Ri 2) For maximum hoop stress: S(pr) = p(Ro 2 + Ri 2) / (Ro 2 - Ri 2) S(bending) = My / I S(torsion shear) = My / JTherefore, the staff requests that the applicant demonstrate that 1D virtual stress for pressure,bending, and torsion can be benchmarked with close form solutions and that they are within a reasonable percentage of deviation.

Letter to T. Garrett, from V. Rodriguez, dated June XX, 2007

SUBJECT:

REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THEWOLF CREEK GENERATING STATION, UNIT 1, LICENSE RENEWAL APPLICATIONDISTRIBUTION

HARD COPY: DLR RFE-MAIL:PUBLICSSmith (srs3)

SDuraiswamy RidsNrrDlr RidsNrrDlrRlra RidsNrrDlrRlrb RidsNrrDlrRlrc RidsNrrDlrReba RidsNrrDlrRebb

RidsNrrDci RidsNrrDra RidsNrrDe RidsNrrDeEemb RidsNrrDeEeeb

RidsNrrDss RidsOgcMailCenter RidsNrrAdes

---

VRodriguez

CJacobs JDonohew GPick, RIV SCochrum, RIV CLong, RIV Wolf Creek Generating Station cc:Jay Silberg, Esq.Pillsbury Winthrop Shaw Pittman, LLP 2300 N Street, NW Washington, DC 20037Regional Administrator, Region IVU.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-7005Senior Resident InspectorU.S. Nuclear Regulatory Commission P.O. Box 311 Burlington, KS 66839Chief Engineer, Utilities DivisionKansas Corporation Commission 1500 SW Arrowhead Road Topeka, KS 66604-4027Office of the GovernorState of Kansas Topeka, KS 66612Attorney General120 S.W. 10 th Avenue, 2 nd FloorTopeka, KS 66612-1597County ClerkCoffey County Courthouse 110 South 6 th StreetBurlington, KS 66839Thomas A. Conley, Section ChiefRadiation and Asbestos Control Kansas Department of Health and Environment Bureau of Air and Radiation 1000 SW Jackson, Suite 310 Topeka, KS 66612-1366Vice President Operations/Plant ManagerWolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KS 66839Supervisor LicensingWolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KS 66839U.S. Nuclear Regulatory CommissionResident Inspectors Office/Callaway Plant

8201 NRC Road Steedman, MO 65077-1032Kevin J. Moles, ManagerRegulatory Affairs Wolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KS 66839Lorrie I. Bell, Project ManagerWolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KS 66839Mr. Gordon A. CleftonNuclear Energy Institute 1776 I Street, NW, Suite 400 Washington, DC 20006-3708