ML072000324

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

ML072000324
Person / Time
Site:	Wolf Creek
Issue date:	07/24/2007
From:	Veronica Rodriguez NRC/NRR/ADRO/DLR/RLRB
To:	Garrett T Wolf Creek
Rodriguez V NRR/DLR/RLRB 415-3703
References
Download: ML072000324 (6)

Text

July 24, 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 10 CFR Part 54, to renew the 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

ML072000324OFFICELA:DLRPM:RLRB:DLRBC:RLRB:DLRNAMEIKingVRodríguezRAuluck DATE07/23/0707/24/0707/24/07 Letter to T. Garrett From V. Rodriguez Dated July 24, 2007

SUBJECT:

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

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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 66839Ms. Julie KeysNuclear Energy Institute 1776 I Street, NW, Suite 400 Washington, DC 20006-3708 EnclosureWOLF CREEK GENERATING STATION, UNIT 1LICENSE RENEWAL APPLICATIONREQUESTS FOR ADDITIONAL INFORMATION (RAIs)RAI 4.3-3By letter dated June 1, 2007, the applicant amended license renewal application (LRA) Section4.3. LRA Section 4.3.1.3 states that all NUREG/CR-6260 sample locations, except for the vessel lower head to shell juncture, were projected from historical and current rates of accumulation of transient cycles and usage factors, using either the cycle-based or the stress-based method of the fatigue management program which is described in LRA Section 4.3.1. In LRA Section 4.3.4, the applicant provided an analysis of these sample locations and stated that the inlet, outlet, and hot leg nozzle predictions used the cycle-based method. The charging, safety injection, and the accumulator-residual heat removal nozzle predictions used the stress-based method.LRA Section 4.3.1.3 states that cycle-based monitoring assumes the alternating stress range ofevery cycle of a transient is equal to that of the design basis, worst-case events assumed by the code fatigue analysis.During the audit, the staff reviewed basis document FP-WOLF-304, which indicates that actualplant transient data (i.e., pressure and temperature) was used for the fatigue usage factor calculation for Period 2 (i.e., from January 13, 1996 through December 31, 2005), and that these values were used to derive backward projected initial cumulative usage factors (CUFs) for Period 1 (i.e., from 1984 through 1995), for each of the 28 locations. The projections were based solely on the ratio of heatups and cooldown cycles for most locations; however, it did not consider other significant transients. For example, the transient tracking report indicates thatseven loss of offsite power cycles and two loss of load cycles occurred between 1984 and March 1992, and that these two transients did not occur again between March 1992 and December 2005. The staff believes that the validity of these CUF backward-projections using the ratio of heatups and cooldown cycles has to be further justified. In its response to audit question TLAAA002, the applicant stated that "The basis of theconclusion that data for accumulated fatigue usage factor per heatup/cooldown during Period 2 is realistic for Period 1 is based on the methodology used for the Period 2 calculations, specifically the numbers surge line insurge/outsurge transients assumed to occur during each heatup/cooldown. The numbers of transients used in the Period 2 analyses were based on data collected during Period 1. Therefore, the calculation methodology used for Period 2 calculations were based on transients typical for Period 1. Usage for Period 1 was calculated on the basis that the incremental usage per heatup/cooldown from Period 2 analyses was applicable to Period 1."The staff reviewed the surge line stratification evaluation report WCAP-12893 which indicatesthat there are 26,000 piping insurge and outsurge cycles for 200 heatups and cooldowns that should be considered if a modified operating procedure (MOP) is not implemented. Wolf Creek Generating Station implemented the MOP prior to 1995 to mitigate piping insurge and outsurge transients. However, the staff reviewed the CUF calculation of FP-WOLF-304 and found that the analyses that used actual transient data for Period 2 does not consider significant pipinginsurge and outsurge cycles from Period 1 to support the validity of the backward projections.

On the basis of its review, the staff finds that the CUF calculations does not support the statement that Period 2 calculations are based on transients typical for Period 1.a)Clarify the discrepancy between design basis events used as stated in LRA 4.3.1 and theactual transient data used in the basis calculation.b)Demonstrate the validity of the baseline CUF for Period 1 using monitoring data fromPeriod 2.