ET 07-0056, Request for Extension of Completion Date for Corrective Actions Associated with NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors.

Request for Extension of Completion Date for Corrective Actions Associated with NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors.

ML073510405
Person / Time
Site:	Wolf Creek
Issue date:	12/05/2007
From:	Garrett T Wolf Creek
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ET 07-0056, GL-04-002, GSI-191, SECY-06-0078
Download: ML073510405 (5)

Text

W0ýLF CREEK 'NUCLEAR OPERATING CORPORATION Terry J. Garrett December 5, 2007 Vice President, Engineering ET 07-0056 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

Reference:

1) Letter WO 06-0028, dated May 31, 2006, from S. E. Hedges, WCNOC, to USNRC

2) Letter dated November 16, 2005, from USNRC to R. A. Muench, WCNOC

Subject:

Docket No. 50-482: Request for Extension of Completion Date for Corrective Actions Associated with NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors" Gentlemen:

By letter dated May 31, 2006 (Reference 1), Wolf Creek Nuclear Operating Corporation (WCNOC) committed to completing all corrective actions associated with Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors," prior to or on December 31, 2007. This submittal requests an extension to delay the completion of remaining corrective actions until June 30, 2008.

In SECY-06-0078, "Status of Resolution of GSI-191, 'Assessment of [Effect of] Debris Accumulation on PWR Sump Performance,"' dated, March 31, 2006, the NRC staff recognized that licensees may encounter situations that could delay the implementation of corrective actions as committed in response to GL 2004-02. SECY-06-0078 describes that proposed extensions to permit completion of corrective actions after December 31, 2007 may be acceptable if, based on the licensee's request, the staff determines that: "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 CSS functions during the extension period."

P.O. Box 411 / Burlington, KS 66839 / Phone: (620) 364-8831 An Equal Opportunity Employer M/F/HCNVET fi

ET 07-0056 Page 2 of 4 WCNOC has the following plant-specific technical/experimental plan with milestones and schedule to address outstanding technical issues with enough margin to account for uncertainties:

• Additional plant-specific tests that support assumptions and corresponding conclusions contained in the GL 2004-02 evaluations for Wolf Creek Generating Station (WCGS) are planned to begin in mid-January, 2008. Although the actual test runs at the vendor testing facility are expected to be completed in late January, 2008, numerous additional actions are required prior to the vendor completing a final test report that meets the procurement specifications requirements, including those of 10 CFR 50, Appendix B for control of purchased services and procurement document control.

• Following receipt of the final test report from the vendor, numerous additional actions are also required by WCNOC to complete formal verification of design inputs, assumptions and conclusions of WCNOC calculations and evaluations conducted in response to issues identified in GL 2004-02. These activities include assessing the impact of the test results on strainer net positive suction head (NPSH) calculations, strainer bypass sampling impact on downstream effects analyses (in-vessel and ex-vessel), as well as potential impact on other Generic Letter 2004-02 corrective action evaluations. These activities also include compliance with 10 CFR 50, Appendix B requirements for design control, document control and quality assurance records.

The following mitigative measures have been or will be put in place prior to December 31, 2007:

" Plant hardware modifications developed in response to issues identified in GL 2004-02, as described in Reference 1, are installed in WCGS and are supporting compliance with the regulatory requirements for long term cooling following a design basis loss of coolant accident. Hardware modifications include replacement of sump strainers, and installation of debris barriers in the "A" and "D" loop entrances.

" Implementation is complete for WCNOC plant administrative procedures and processes described in Reference 1 to support the GL 2004-02 hardware modifications and revised operating practices, as well as to support the assumptions, initial conditions and conclusions of the expected final version of GL 2004-02 related evaluations, when the evaluations are completed and documented. Administrative procedures and processes include implementation of changes to programmatic controls for design change processes and containment material controls, as well as implementation of a containment coatings assessment program and a containment latent debris assessment program.

• Interim compensatory measures implemented at WCGS in accordance with NRC Bulletin 2003-01, "Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors," as described in NRC's closeout to the bulletin (Reference 2), remain in effect to minimize interim risks associated with post-accident debris blockage while GL 2004-02 evaluations are being completed. In accordance with NRC Bulletin 2003-01, these measures will remain in place at a minimum until all evaluations and corrective actions for GL 2004-02 are complete.

ET 07-0056 Page 3 of 4 This letter transmits changes in WCNOC's regulatory commitments contained in Reference 1.

The commitment changes are being submitted in accordance with guidance provided by industry document NEI 99-04, "Guidelines for Managing NRC Commitment Changes," as endorsed in Regulatory Issues Summary 00-017, "Managing Regulatory Commitments Made by Power Reactor Licensees to the NRC Staff." Attachment I lists the WCNOC commitments contained in this letter. Commitments contained in this letter supersede those previously contained in Reference 1.

If you have any questions concerning this matter, please contact me at (620) 364-4084, or Mr.

Kevin Moles at (620) 364-4126.

Sincerely, Terry J. Garrett TJG/rlt Attachment I: List of Regulatory Commitments cc: E. E. Collins (NRC), w/a J. N. Donohew (NRC), w/a V. G. Gaddy (NRC), w/a Senior Resident Inspector (NRC), w/a

ET 07-0056 Page 4 of 4 STATE OF KANSAS )

COUNTY OF COFFEY )

Terry J. Garrett, of lawful age, being first duly sworn upon oath says that he is Vice President Engineering of Wolf Creek Nuclear Operating Corporation; that he has read the foregoing document and knows the contents thereof; that he has executed the same for and on behalf of said Corporation with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.

By_ -9*

Terry J. r*rett Vice Pr ident Engineering SUBSCRIBED and sworn to before me this-- day of&,jvh,2007.

GAYLE SHEPEARD 1 Notary MNotary Public - State of KansasI My Appt. Expires 7/1a q/O /

Expiration Date "Idq IIdQ) I

Attachment I to ET 07-0056 Page 1 of 1 List of Regulatory Commitments The following table identifies revised due dates for those actions originally committed to by Wolf Creek Nuclear Operating Corporation in Reference 1. The numbering in this table is maintained consistent with Reference 1. Any other statements in this letter are provided for information purposes and are not considered to be regulatory commitments. Please direct questions regarding these commitments to Mr. Kevin Moles, Manager Regulatory Affairs at Wolf Creek Generating Station, (620) 364-4126.

Regulatory Commitment Due Date

1. The following corrective action activities will be completed:

a. Using WCAP-16406-P, evaluate the effects of debris-laden fluid on a. June 30, 2008 systems and components downstream of the containment emergency sump strainers during the ECCS recirculation phase of design basis accidents.

b. Using NEI 04-07, evaluate the effects of design basis accident b. June 30, 2008 conditions on the ability of structures, systems and components upstream of the containment emergency sump strainers to mitigate the consequences of the analyzed accidents.

2. Submit an update to information contained in WCNOC's response to June 30, 2008 Generic Letter 2004-02 Requested Information Item 2.

3. The following evaluations and testing will be completed:

b. Using NEI 04-07, perform a debris generation calculation for the b. June 30, 2008 analyzed design basis accidents.

c. Using NEI 04-07, perform a debris transport calculation for the c. June 30, 2008 analyzed design basis accidents.

d. Evaluate the impact of chemical effects on containment emergency d. June 30, 2008 sump strainer head loss during design basis accident conditions.

e. Complete head loss testing of the replacement containment e. June 30, 2008 emergency sump strainer.

f. Confirm that the available NPSH of the replacement containment f. June 30, 2008 emergency sump strainers during design basis accident conditions is in excess of the required NPSH.

4. Complete the final site acceptance review of the Westinghouse June 30, 2008 evaluation team analysis summary report.

5. The following items will be completed:

c. Modify safety injection system components, if required, based on c. June 30, 2008 the results of the downstream effects evaluation.

6. Remove the containment spray system pump cyclone separators, if June 30, 2008 required, based on the results of the downstream effects evaluation.

9. Implement all plant modifications and related administrative controls June 30, 2008 that support the NEI 04-07 analysis package.