ML081770651
| ML081770651 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 06/27/2008 |
| From: | Hiltz T NRC/NRR/ADRO/DORL/LPLIV |
| To: | Entergy Operations |
| Wang, A B, NRR/DORL/LPLIV, 415-1445 | |
| References | |
| GL-04-002, TAC MD4663 | |
| Download: ML081770651 (5) | |
Text
June 27, 2008 Vice President, Operations Arkansas Nuclear One Entergy Operations, Inc.
1448 S.R. 333 Russellville, AR 72802
SUBJECT:
ARKANSAS NUCLEAR ONE, UNIT 1 - GENERIC LETTER 2004-02, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS," EXTENSION REQUEST APPROVAL (TAC NO. MD4663)
Dear Sir or Madam:
Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors," requested that all licensees complete actions related to the GL by December 31, 2007. By letter dated June 19, 2008 (Agencywide Document Access and Management System (ADAMS) Accession No. ML081710533), Entergy Operations, Inc. (Entergy, the licensee) requested a third extension to the completion date for its corrective actions to be taken at the Arkansas Nuclear One, Unit 1 (ANO-1). The stated intent of this extension was to allow Entergy additional time to complete the downstream effects analysis on the high-pressure injection (HPI) pump.
The U.S. Nuclear Regulatory Commission (NRC) previously approved an extension, requested on November 7, 2007 (ADAMS Accession No. ML073270060) by NRC letter dated December 21, 2007 (ADAMS Accession No., ML073520302), which provided for completion of final strainer certification/qualification calculations and licensing basis updates for GSI-191 by the end of June 2008. In a letter dated April 24, 2008 (ADAMS Accession No. ML081160051),
Entergy had requested a second extension to the completion date for its corrective actions for ANO-1. Entergy stated that it had completed the in-vessel downstream effects analysis and strainer head-loss report; however, the remainder of the ANO-1 analyses was not complete.
The NRC correspondence dated April 30, 2008 (ADAMS Accession No. ML081210212),
approved Entergys requested extension until June 30, 2008, to complete the remaining analyses to support GL 2004-02 resolution (including ex-vessel downstream effects analysis) and update the ANO-1 licensing basis, and until July 31, 2008, to provide the final GL 2004-02 supplemental response.
In its June 19, 2008 request, Entergy stated that due to difficulty in establishing an accurate model for the HPI pump by the original analysis vendor, the licensee contracted the pump vendor to evaluate the downstream effects on an expedited basis. Licensee interactions with the pump vendor to improve the delivery schedule were not successful due to a limited number of expert personnel at the pump vendor and pump vendor competing priority workload. Entergy further stated that the safety impact of the extension request is minimal because it does not anticipate adverse analysis results for the HPI pump, based on licensee discussions with the pump vendor and the vendors preliminary review of the debris loads.
In an attachment to an E-mail sent June 17, 2008 (ADAMS Accession No. ML081720337),
Entergy noted it is not confident that all documents could be completed and approved to support the current schedule. In addition, Entergy has combined the documentation necessary to support GL 2004-02 into an integrated design package to implement the design bases changes.
Since significant difficulty would be involved in revising the currently integrated design package to implement it without the HPI pump analysis, Entergy requested extension of the overall compliance date even though the specific HPI analysis has a relatively narrow scope.
Entergy stated in its June 19, 2008, letter that the basis for the acceptability of this extension remains the same as the basis provided in Entergys November 7, 2007, extension request and in the December 21, 2007, NRC approval letter. Therefore, Entergy requested an extension until August 15, 2008, to finalize the analyses to support GL 2004-02 resolution including updating the ANO-1 licensing basis, and until September 15, 2008, to provide the final supplemental response.
The NRC bases its review of extension requests for the due date for completion of GL 2004 02 corrective actions on criteria stated in SECY-06-0078, Status of Resolution of GSI-191, Assessment of [Effect of] Debris Accumulation on PWR Sump Performance. 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,
- 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 emergency core cooling system (ECCS) and containment spray system (CSS) functions during the extension period.
The SECY 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, Entergy provided the technical basis in its November 7, 2007, letter. In addition, Entergy has committed to complete analyses to support GL 2004-02 resolution (including HPI pump downstream effects analysis) and update the ANO-1 licensing basis by August 15, 2008, and to provide the final supplemental response for ANO-1 by September 15, 2008.
With regard to the second extension criterion, mitigative measures, compensatory measures and favorable conditions remain in effect in ANO-1, as previously described in the December 21, 2007, NRC letter. In addition to the measures listed in the NRC letter, during a previous telephone conversation with the NRC staff on April 22, 2008, Entergy stated that it has completed the buffer concentration change for ANO-1.
With regard to temporary physical modifications, Entergy anticipates completion of all the actions necessary to support GL 2004-02 resolution by June 30, 2008, with the exception of a
downstream effects analysis on the HPI pump and finalizing documentation of the GL 2004-02 analyses. Given the relatively small amount of additional time involved and the licensees expectation that all corrective actions for GL 2002-04 other than the HPI pump analysis will be compete by June 30, 2008, the NRC staff believes the safety significance of the extension is small. The NRC staff therefore does not consider that the licensee needs to implement additional measures to mitigate the delay in final documentation.
The NRC staff believes that Entergy has a reasonable plan for ANO-1 that should result in the completion of final GL 2004-02 corrective actions that provide acceptable strainer function with adequate margin for uncertainties. The additional impact associated with granting this extension is considered to be of low safety concern given the mitigation measures and plant improvements already in place. Based on the licensee having satisfactorily addressed the NRC GL 2004-02 due date extension criteria as discussed above, the NRC finds it is acceptable to extend the completion date for GL 2004-02 corrective actions associated with sump strainer confirmatory analysis and validation, as described in this enclosure, for ANO-1 to August 15, 2008. Should the time for potential ANO-1 corrective actions be determined by Entergy to extend beyond September 15, 2008, Entergy will need to submit an additional extension request to the NRC.
While the NRC accepts these dates as reasonable allowance for contingencies regarding completion of remaining activities to address GL 2004-02, the NRC expects Entergy to place a high priority on completing remaining actions and updating the plants licensing bases as soon as possible.
If you have any questions or comments regarding this approval, please contact Alan Wang at 301-415-1445.
Sincerely,
/RA/
Thomas Hiltz, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-313 cc: See next page
- Concurrence via e-mail OFFICE NRR/LPL4/PM NRR/LPL4/LA ADES/SSIB/BC* NRR/LPL4/BC NAME AWang (*) GLappert MScott (*)LWhitney for THiltz DATE 6/26/08 6/26/08 6/26/08 6/27/08 Arkansas Nuclear One (6/19/08) cc:
Senior Vice President Section Chief, Division of Health Entergy Nuclear Operations Radiation Control Section P.O. Box 31995 Arkansas Department of Health and Jackson, MS 39286-1995 Human Services 4815 West Markham Street, Slot 30 Vice President, Oversight Little Rock, AR 72205-3867 Entergy Nuclear Operations P.O. Box 31995 Section Chief, Division of Health Jackson, MS 39286-1995 Emergency Management Section Arkansas Department of Health and Senior Manager, Nuclear Safety Human Services
& Licensing 4815 West Markham Street, Slot 30 Entergy Nuclear Operations Little Rock, AR 72205-3867 P.O. Box 31995 Jackson, MS 39286-1995 Pope County Judge Pope County Courthouse Senior Vice President 100 W. Main Street
& Chief Operating Officer Russellville, AR 72801 Entergy Operations, Inc.
P.O. Box 31995 Senior Resident Inspector Jackson, MS 39286-1995 U.S. Nuclear Regulatory Commission P.O. Box 310 Associate General Counsel London, AR 72847 Entergy Nuclear Operations P.O. Box 31995 Regional Administrator, Region IV Jackson, MS 39286-1995 U.S. Nuclear Regulatory Commission 612 E. Lamar Blvd., Suite 400 Manager, Licensing Arlington, TX 76011-4125 Entergy Operations, Inc.