ML071780563
| ML071780563 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 07/09/2007 |
| From: | Veronica Rodriguez NRC/NRR/ADRO/DLR/RLRB |
| To: | |
| Rodriguez V NRR/DLR/RLRB 415-3703 | |
| References | |
| Download: ML071780563 (7) | |
Text
July 9, 2007 LICENSEE: Wolf Creek Nuclear Operating Corporation FACILITY:
Wolf Creek Generating Station, Unit 1
SUBJECT:
SUMMARY
OF TELEPHONE CONFERENCE CALL HELD ON JUNE 13, 2007, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND WOLF CREEK NUCLEAR OPERATING CORPORATION, CONCERNING 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 June 13, 2007, to discuss and clarify the staffs requests for additional information (RAIs) concerning the Wolf Creek Generating Station, Unit 1, license renewal application. The telephone conference call was useful in clarifying the intent of the staffs RAIs. provides a listing of the participants and Enclosure 2 contains a listing of the 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. A mutually agreeable 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.
/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 Requests for Additional Information cc w/encls: See next page
ML071780563 OFFICE LA:DLR PM:RLRB:DLR BC:RLRB:DLR NAME IKing VRodríguez RAuluck DATE 07/02/07 07/03/07 07/09/07
Letter to Wolf Creek Nuclear Operating Corporation from V. Rodriguez Dated July 9, 2007
SUBJECT:
SUMMARY
OF TELEPHONE CONFERENCE CALL HELD ON JUNE 13, 2007, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND WOLF CREEK NUCLEAR OPERATING CORPORATION, CONCERNING REQUESTS FOR ADDITIONAL INFORMATION PERTAINING TO THE WOLF CREEK GENERATING STATION, UNIT 1, LICENSE RENEWAL APPLICATION DISTRIBUTION:
HARD COPY:
DLR RF E-MAIL:
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Wolf Creek Generating Station cc:
Jay Silberg, Esq.
Pillsbury Winthrop Shaw Pittman, LLP 2300 N Street, NW Washington, DC 20037 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-7005 Senior Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 311 Burlington, KS 66839 Chief Engineer, Utilities Division Kansas Corporation Commission 1500 SW Arrowhead Road Topeka, KS 66604-4027 Office of the Governor State of Kansas Topeka, KS 66612 Attorney General 120 S.W. 10th Avenue, 2nd Floor Topeka, KS 66612-1597 County Clerk Coffey County Courthouse 110 South 6th Street Burlington, KS 66839 Thomas A. Conley, Section Chief Radiation and Asbestos Control Kansas Department of Health and Environment Bureau of Air and Radiation 1000 SW Jackson, Suite 310 Topeka, KS 66612-1366 Vice President Operations/Plant Manager Wolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KS 66839 Supervisor Licensing Wolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KS 66839 U.S. Nuclear Regulatory Commission Resident Inspectors Office/Callaway Plant 8201 NRC Road Steedman, MO 65077-1032 Kevin J. Moles, Manager Regulatory Affairs Wolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KS 66839 Lorrie I. Bell, Project Manager Wolf Creek Nuclear Operating Corporation P.O. Box 411 Burlington, KS 66839 Mr. Gordon A. Clefton Nuclear Energy Institute 1776 I Street, NW, Suite 400 Washington, DC 20006-3708 TELEPHONE CONFERENCE CALL WOLF CREEK GENERATING STATION, UNIT 1 LICENSE RENEWAL APPLICATION LIST OF PARTICIPANTS JUNE 13, 2007 PARTICIPANTS AFFILIATIONS Verónica M. Rodríguez U.S. Nuclear Regulatory Commission (NRC)
George Wilson NRC Sheila Ray NRC Vijay Goel NRC Duc Nguyen NRC Lorrie Bell Wolf Creek Nuclear Operating Corporation (WCNOC)
Luo Solorio WCNOC Eric Blocher Strategic Teaming and Resource Sharing Alliance (STARS)
Paul Crawley STARS Gary Warner STARS Rich Schaller STARS REQUESTS FOR ADDITIONAL INFORMATION WOLF CREEK GENERATING STATION, UNIT 1 LICENSE RENEWAL APPLICATION JUNE 13, 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 June 13, 2007, as a follow-up discussion and request for clarification to the applicants response to the following request for additional information (RAI) concerning the Wolf Creek Generating Station (WCGS),
Unit 1, license renewal application (LRA). The applicants response to this RAI was submitted by letter dated May 9, 2007.
RAI 2.5-1 LRA Section 2.5 does not explicitly describe the offsite recovery paths (from the switchyard to the onsite distribution system) for a station blackout (SBO).
The General Design Criterion 17 described in Title 10 Code of Federal Regulations Part 50 (10 CFR Part 50), Appendix A, requires that electric power from the transmission network to the onsite electric distribution system be supplied by two physically independent circuits to minimize the likelihood of their simultaneous failure.
In addition, the guidance provided by letter dated April 1, 2002, Staff Guidance on Scoping of Equipment Relied on to Meet the Requirements of the Station Blackout Rule (10 CFR 50.63) for License Renewal (10 CFR 54.4(a)(3)), states:
For purposes of the license renewal rule, the staff has determined that the plant system portion of the offsite power system that is used to connect the plant to the offsite power source should be included within the scope of the rule. This path typically includes switchyard circuit breakers that connect to the offsite system power transformers (startup transformers), the transformers themselves, the intervening overhead or underground circuits between circuit breaker and transformer and transformer and onsite electrical system, and the associated control circuits and structures. Ensuring that the appropriate offsite power system long-lived passive structures and components that are part of this circuit path are subject to an aging management review will assure that the bases underlying the SBO requirements are maintained over the period of extended license.
According to the above, both paths that are used to control the offsite circuits to the plant should be age managed. According to LRA drawing LR-WCGS-ELEC-KD-7496, the high voltage switchyard circuit breakers, underground cables, and its associated components and structures are not presently included within the scope of license renewal. The staff requests that the applicant justify why these components are not within the scope of license renewal. In addition the staff requests that the applicant explain in detail which high voltage breakers and other components in the switchyard will be connected from the startup transformer XMR01 and ESF No. 1 transformer XNB01 up to the offsite power system for the purpose of SBO recovery.
Discussion: Based on the discussion with the applicant, the staff indicated that the response to this RAI requires clarification. The staff reiterated its position regarding the scoping of equipment relied on to meet the requirements of SBO established by letter dated April 1, 2002.
The staff noted that for SBO recovery, the path should include the first breaker from the offsite lines in the switchyard to the startup transformers up to the safety-related 4.16kV buses. The staff clarified that the guidance does not specify that the switchyard is not part of the plant systems, nor does it specify that the switchyard does not need to be included within the scope of license renewal. Thus, the staff noted that the first switchyard circuit breaker (from the grid, i.e., offsite transmission line), startup transformer, intervening overhead or underground circuits between the breaker and transformer as well as between the transformers and onsite electrical distribution system, and associated control circuits and structures for the two SBO recovery paths should be included within the scope of license renewal. The staff indicated that for each SBO recovery path, the scope of license renewal should cover up to and including the first circuit breaker from any one of the three offsite transmission lines (i.e., grid).
RAI 2.5-3 There has been operating experience regarding the failure of cable tie-wraps caused by the brittleness of the plastic material. The cable tie-wraps are long-lived passive components. Its intended functions include to maintain spacing for power cable ampacity, maintain stiffness in unsupported lengths of wire bundles to ensure minimum bending radius, and maintain cables within vertical raceways, among others. Most recently, at Point Beach, the regional inspectors identified an unresolved item after noticing that the current configuration of the plant may not be consistent with plant design documents due to the age related breakage of a large number of plastic tie-wraps used to fasten wires and cables. At Point Beach, cable tie-wraps are part of the cable design in order to maintain cable ampacity or are credited in the licensee's Seismic Qualifications Utility Group to seismically qualify the cable tray system. The staff requests that the applicant explain how WCGS manages the aging of cable tie-wraps. In addition, the staff requests that the applicant justify why the cable tie-wraps are not included within the scope of license renewal in accordance with the requirements of 10 CFR 54.4.
Discussion: Based on the discussion with the applicant, the staff indicated that the response to this RAI requires clarification. The staff understands that the cable tie wraps are not credited in the WCGS seismic qualification of the cable tray support system. However, the staff noted that there is operating experience showing instances in which degraded cable tie-wraps has failed and lodged in components preventing the performance of their intended functions. The staff requested that the applicant clarify if WCGS considered the potential effect on safety-related equipment caused by the failure of plastic cable tie-wraps due to age-related degradation.