ML072700054

Summary of Telephone Conference Call Held on 9/26/07, Between the U.S. NRC and Wolf Creek Nuclear Operating Corporation, Concerning Draft Requests for Additional Information Pertaining to the Wolf Creek Generating Station, Unit 1, LRA

ML072700054
Person / Time
Site:	Wolf Creek
Issue date:	10/02/2007
From:	Veronica Rodriguez NRC/NRR/ADRO/DLR/RLRB
To:	Wolf Creek
Rodriguez V
References
Download: ML072700054 (7)

Text

October 2, 2007 LICENSEE: Wolf Creek Nuclear Operating Corporation FACILITY: Wolf Creek Generating Station, Unit 1

SUMMARY

OF TELEPHONE CONFERENCE CALL HELD ON SEPTEMBER 26, 2007, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND WOLF CREEK NUCLEAR OPERATING CORPORATION, CONCERNING DRAFT REQUESTS FOR ADDITIONAL INFORMATION PERTAINING TO THE WOLF CREEK GENERATING STATION, UNIT 1, LICENSE RENEWAL APPLICATION The U.S. Nuclear Regulatory Commission (NRC or the staff) and representatives of Wolf Creek Nuclear Operating Corporation held a telephone conference call on September 26, 2007, to discuss and clarify the staff=s draft requests for additional information (D-RAIs) concerning the Wolf Creek Generating Station, Unit 1, license renewal application. The telephone conference call was useful in clarifying the intent of the staff=s D-RAIs. provides a listing of the participants and Enclosure 2 contains a listing of the D-RAIs discussed with the applicant, including a brief description on the status of the items.

The applicant had an opportunity to comment on this summary.

/RA/

Verónica M. Rodríguez, Project Manager License Renewal Branch B Division of License Renewal Office of Nuclear Reactor Regulation Docket No. 50-482

Enclosures:

1. List of Participants

2. List of Draft Requests for Additional Information cc w/encls: See next page

ML072700054 OFFICE LA:DLR PM:RLRB:DLR BC:RLRB:DLR NAME IKing VRodríguez RAuluck DATE 09/28/07 10/01/07 10/02/07 TELEPHONE CONFERENCE CALL WOLF CREEK GENERATING STATION, UNIT 1 LICENSE RENEWAL APPLICATION LIST OF PARTICIPANTS SEPTEMBER 26, 2007 PARTICIPANTS AFFILIATIONS Veronica M. Rodriguez U.S. Nuclear Regulatory Commission (NRC)

Kenneth Karwoski NRC Lorrie Bell Wolf Creek Nuclear Operating Corporation (WCNOC)

Patrick Wagner WCNOC Jeff Tarr WCNOC Enclosure 1

DRAFT REQUESTS FOR ADDITIONAL INFORMATION WOLF CREEK GENERATING STATION, UNIT 1 LICENSE RENEWAL APPLICATION SEPTEMBER 26, 2007 The U.S. Nuclear Regulatory Commission (NRC or the staff) and representatives of Wolf Creek Nuclear Operating Corporation held a telephone conference call on September 26, 2007, to discuss and clarify the following draft requests for additional information (D-RAIs) concerning the Wolf Creek Generating Station (WCGS), Unit 1, license renewal application (LRA).

D-RAI B2.1.8-1 The LRA states that the rotating pancake probe is used to inspect from 3 inches above to 3 inches below the top of the tubesheet and that the bobbin probe is used to inspect the entire engagement length of the hydraulically expanded tubesheet region. However, the bobbin probe is not qualified for inspection in this area. The application also states that there was a one-cycle license amendment request to use an alternate tube repair criteria which, in part, eliminated the need to inspect near the tube ends on the hot-leg side of the steam generator.

The Electric Power Research Institute (EPRI) guidelines indicate that the full length of the steam generator tubes requires an inspection with an inspection technique qualified for each region of the tube.

The staff requests that the applicant clarify this exception to the Generic Aging Lessons Learned (GALL) Report and the EPRI guidelines. For example, clarify whether the exception being taken to the EPRI guidelines is that the entire tube is not inspected or whether WCGS is not inspecting the portions of the tube required to be inspected with techniques capable of detecting flaws that may be occurring in that region. The staff notes that the tube is required to be inspected with the objective of detecting flaws of any type and that may satisfy the applicable tube repair criteria (WCGS technical specification 5.5.9.d). As a result, if cracking of the tube could occur at various locations within the tubesheet, these areas should be inspected with techniques capable of finding these flaws (and consistent with the sampling and tube integrity requirements of the technical specifications). The staff notes that inspection near the tube ends on the hot-leg side of the steam generator is not required for refueling outage fifteen and the subsequent operating cycle (since this portion of tube is explicitly exempted from the inspection requirements in the technical specifications).

Discussion: The applicant indicated that the question is clear. The applicant clarified that WCGS is no longer taking exceptions to the GALL Report and that the LRA will be amended accordingly. This D-RAI will be sent as a formal RAI.

D-RAI B2.1.8-2 The LRA states that the bobbin probe is used to detect primary water stress corrosion cracking at tube dents in support plates and stress corrosion cracking in free span regions. However, the bobbin probe is not qualified for detection of these degradation mechanisms when the voltage Enclosure 2

of the dent exceeds certain threshold values. The EPRI guidelines indicate that the full length of the steam generator tubes requires an inspection with an inspection technique qualified for each region of the tube.

The staff requests that the applicant clarify the nature of this exception to the GALL Report and EPRI guidelines since the WCGS technical specifications require, in part, to (a) perform an assessment of the type and location of flaws to which the tubes may be susceptible and, based on this assessment, to determine which inspection methods need to be employed and at what locations; and (b) to inspect the tubes with the objective of detecting flaws that may satisfy the applicable tube repair criteria.

In light of these requirements, if WCGS concludes that primary water stress corrosion cracking could occur at tube dents in support plates or outer diameter stress corrosion cracking could occur in free span regions, these regions should be inspected with techniques capable of finding these forms of degradation.

Discussion: The applicant indicated that the question is clear. The applicant clarified that WCGS is no longer taking exceptions to the GALL Report and that the LRA will be amended accordingly. This D-RAI will be sent as a formal RAI.

D-RAI B2.1.8-3 The LRA indicates that the EPRI guidelines require that if active damage mechanisms are identified then all steam generators shall be examined at the end of each fuel cycle. The application also states that although WCGS currently has one active damage mechanism (i.e., wear at anti-vibration bars), only two steam generators are inspected at each refueling outage on an alternating basis so that each steam generator is examined every other refueling outage.

The staff requests that the applicant confirm that WCGS has verified the acceptability of this approach each outage by confirming that tube integrity will be maintained for the period of time between the planned inspections of the steam generators (consistent with the technical specification requirements).

Discussion: The applicant indicated that the question is clear. The applicant clarified that WCGS verifies the acceptability of this approach each refueling outage. This D-RAI will be sent as a formal RAI.

D-RAI B2.1.8-4 The LRA states that structural integrity limits consistent with Regulatory Guide 1.121, ABases for Plugging Degraded PWR Steam Generator Tubes@ are applied as part of the Steam Generator Tube Integrity Aging Management Program (AMP). The staff requests that the applicant confirm that the AMP also includes the structural integrity limits contained within the WCGS technical specifications.

Discussion: The applicant indicated that the question is clear. This D-RAI will be sent as a formal RAI.

Memo to Wolf Creek Nuclear Operating Corporation from V. Rodriguez dated October 02, 2007 DISTRIBUTION:

SUMMARY

OF TELEPHONE CONFERENCE CALL HELD ON SEPTEMBER 26, 2007, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND WOLF CREEK NUCLEAR OPERATING CORPORATION, CONCERNING DRAFT REQUESTS FOR ADDITIONAL INFORMATION PERTAINING TO THE WOLF CREEK GENERATING STATION, UNIT 1, LICENSE RENEWAL APPLICATION HARD COPY DLR RF E-MAIL:

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Wolf Creek Generating Station cc:

Jay Silberg, Esq. Vice President Operations/Plant Manager Pillsbury Winthrop Shaw Pittman, LLP Wolf Creek Nuclear Operating Corporation 2300 N Street, NW P.O. Box 411 Washington, DC 20037 Burlington, KS 66839 Regional Administrator, Region IV Supervisor Licensing U.S. Nuclear Regulatory Commission Wolf Creek Nuclear Operating Corporation 611 Ryan Plaza Drive, Suite 400 P.O. Box 411 Arlington, TX 76011-7005 Burlington, KS 66839 Senior Resident Inspector U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission Resident Inspectors Office/Callaway Plant P.O. Box 311 8201 NRC Road Burlington, KS 66839 Steedman, MO 65077-1032 Chief Engineer, Utilities Division Kevin J. Moles, Manager Kansas Corporation Commission Regulatory Affairs 1500 SW Arrowhead Road Wolf Creek Nuclear Operating Corporation Topeka, KS 66604-4027 P.O. Box 411 Burlington, KS 66839 Office of the Governor State of Kansas Lorrie I. Bell, Project Manager Topeka, KS 66612 Wolf Creek Nuclear Operating Corporation P.O. Box 411 Attorney General Burlington, KS 66839 120 S.W. 10th Avenue, 2nd Floor Topeka, KS 66612-1597 County Clerk Coffey County Courthouse 110 South 6th Street Burlington, KS 66839 Chief, Radiation and Asbestos Control Section Kansas Department of Health and Environment Bureau of Air and Radiation 1000 SW Jackson, Suite 310 Topeka, KS 66612-1366