ML081780163
| ML081780163 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 06/27/2008 |
| From: | Balwant Singal NRC/NRR/ADRO/DORL/LPLIV |
| To: | Muench R Wolf Creek |
| singal, balwant NRR/DORL 301-415-3016 | |
| References | |
| GL-04-002, TAC MD4731 | |
| Download: ML081780163 (6) | |
Text
June 27, 2008 Mr. Rick A. Muench President and Chief Executive Officer Wolf Creek Nuclear Operating Corporation Post Office Box 411 Burlington, KS 66839
SUBJECT:
WOLF CREEK GENERATING STATION - GENERIC LETTER 2004-02, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED WATER REACTORS," EXTENSION REQUEST (TAC NO. MC4731)
Dear Mr. Muench:
The U.S. Nuclear Regulatory Commission (NRC) has evaluated the information provided in Wolf Creek Nuclear Operating Corporations letter dated June 20, 2008, supporting a request for an extension of the due date for certain Wolf Creek Generating Station (WCGS) corrective actions for Generic Letter 2004-02, "Potential Impact Of Debris Blockage On Emergency Recirculation During Design Basis Accidents At Pressurized Water Reactors." The NRC has determined that for WCGS, it is acceptable to extend the due date for completion of certain corrective actions, as described in the enclosure, until September 30, 2008.
If you have any questions regarding this matter, I may be reached at 301-415-3016.
Sincerely,
/RA/
Balwant K. Singal, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-482
Enclosure:
As stated cc w/encl: See next page
- Memo dated 6/ 25/2008 OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/SSIB/BC NRR/LPL4/BC NRR/LPL4/PM NAME BSingal JBurkhardt MScott (*)
THiltz BSingal DATE 6/26/08 6/26/08 6/25/08 6/27/08 6/27/08
Wolf Creek Generating Station 6/10/2008 cc:
Jay Silberg, Esq.
Pillsbury Winthrop Shaw Pittman LLP 2300 N Street, NW Washington, D.C. 20037 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 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 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 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
1 As of the date of issuance of this letter and enclosure, document not yet placed into ADAMS.
Enclosure EXTENSION REQUEST TO COMPLETE CORRECTIVE ACTIONS GENERIC SAFETY ISSUE-191 ASSESSMENT OF DEBRIS ACCUMULATION ON PRESSURIZED-WATER REACTOR SUMP PUMP PERFORMANCE GENERIC LETTER 2004-02, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED WATER REACTORS WOLF CREEK GENERATING STATION DOCKET NO. 50-482 By letter dated June 20, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML08xxxxxxx1), Wolf Creek Nuclear Operating Corporation (the licensee) requested an extension to the U.S. Nuclear Regulatory Commission (NRC) Generic Letter (GL) 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors, corrective actions due date for Wolf Creek Generating Station (WCGS). The stated intent of this extension was to allow the licensee additional time to complete certain corrective actions for GL 2004-02 because of delays in receipt of documentation of vendor testing for emergency core cooling system (ECCS) strainers.
The licensee requested an extension to September 30, 2008, for completion of the specified activities.
By letter dated December 5, 2007, the licensee had previously submitted a request for extension of the WCGS sump clogging corrective actions due date of December 31, 2007, stated in GL 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized Water Reactors. The licensee stated that additional time was needed to complete plant-specific testing and related activities, including completion of licensee verification of design inputs, calculations, and evaluations. The NRC staff reviewed the information provided and determined that it was acceptable to extend the due date for completion of corrective actions at WCGS for GL 2004-02 to June 30, 2008 (NRC letter dated December 27, 2007, ADAMS Accession No. ML073610147).
The licensee stated in its June 20, 2008, letter that it had successfully completed strainer performance testing with an established test protocol using input from the NRC staff that showed adequate net positive suction head (NPSH) margin would be maintained, that chemical effects were minimal, and that testing confirmed the effectiveness of the new strainer design and its resistance to blockage from transported debris. Bypass testing was also performed. The licensee concluded, therefore, that corrective actions are nearly complete.
The licensee noted, however, that additional time is needed to:
Obtain the final vendor test report (scheduled for mid-August 2008), and
Assess the impact of the test results on 1) strainer calculations, 2) bypass sample impacts on downstream effects evaluations, and 3) other GL 2004-02 corrective actions, including completion of activities needed to comply with Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Appendix B, by September 30, 2008.
The NRC has based its reviews for granting extensions to the due date for completion of GL 2004-02 corrective actions on the criteria stated in SECY-06-0078. Specifically, an extension may be granted if:
the licensee has a plant-specific technical/experimental plan with milestones and schedule to address outstanding technical issues with enough margin to account for uncertainties, and the licensee identifies mitigative measures to be put in place prior to December 31, 2007, and adequately describes how these mitigative measures will minimize the risk of degraded ECCS and containment spray system functions during the extension period.
SECY-06-0078 also states that for proposed extensions beyond several months, a licensees request will more likely be accepted if the proposed mitigative measures include temporary physical improvements to the ECCS sump or materials inside containment to better ensure a high level of ECCS sump performance.
With regard to the first extension criterion, the licensee has provided a plant-specific technical/experimental plan, with milestones and schedules, to complete the GL 2004-02 corrective actions, as discussed above.
With regard to the second extension criterion, the licensee stated in its letter dated June 20, 2008, that the following mitigative measures are in place:
Plant hardware modifications, developed in response to issues identified in GL 2004-02, are installed in WCGS and are actively supporting compliance with the regulatory requirements for long-term cooling following a design basis loss-of-coolant accident. Hardware modifications include replacement of ECCS sump screens with new strainers with a surface area of 6623 square feet, and installation of debris barriers in two loop entrances. These modifications are intended to maximize strainer capability while minimizing the debris load to the extent practical.
Plant administrative procedures and processes, such as programmatic changes to controls for plant design changes and containment material controls, have been implemented to support the hardware modifications.
Interim compensatory measures implemented in accordance with NRC Bulletin 2003-02 remain in effect.
In summary, the licensee has stated that it believes it has nearly completed corrective actions for GL 2004-02 and that it has demonstrated adequate NPSH through testing. Given this situation
and the mitigation measures and plant improvements already in place, the additional time requested in the June 20, 2008, letter to complete remaining evaluations and documentation is considered to be of low safety concern. Based on the licensee having satisfactorily addressed the GL 2004-02 due date extension criteria as discussed above, the NRC staff finds it acceptable to extend the completion date for GL 2004-02 corrective actions associated with strainer performance testing, final analysis, and related licensing activities, as described in this enclosure, for WCGS to September 30, 2008.