ML081210212
| ML081210212 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  (DPR-051, NPF-006) |
| Issue date: | 04/30/2008 |
| From: | Hiltz T NRC/NRR/ADRO/DORL/LPLIV |
| To: | Entergy Operations |
| Wang A, NRR/DORL/LPL4, 301-415-1445 | |
| References | |
| GL-04-002, TAC MD8546, TAC MD8570 | |
| Download: ML081210212 (6) | |
Text
April 30, 2008 Vice President, Operations Arkansas Nuclear One Entergy Operations, Inc.
1448 S. R. 333 Russellville, AR 72802
SUBJECT:
ARKANSAS NUCLEAR ONE, UNITS 1 AND 2 - APPROVAL OF EXTENSION REQUEST FOR CORRECTIVE ACTIONS RE: GENERIC LETTER 2004-02, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS" (TAC NOS. MD8570 AND MD8546)
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 [PWRs]," requested that all licensees complete actions related to the GL by December 31, 2007. In a teleconference with the U.S. Nuclear Regulatory Commission (NRC) staff on April 4, 2008, Entergy Operations, Inc.
(Entergy, the licensee), described an insulation configuration discovered during the spring 2008 refueling outage (2R19) that affected its ability to complete the analyses to support GL 2004-02 resolution. During 2R19, additional fibrous insulation was discovered in the Arkansas Nuclear One, Unit 2 (ANO-2) containment that had not been previously considered in the GL 2004-02 calculations. Entergy stated that it has undertaken aggressive actions to address the condition by removing the vast majority of the newly identified fibrous insulation, but there were several areas that were not addressed due to the relatively high radiation fields where the fibrous insulation was located. These changes to the potential debris mixture required Entergy to repeat some of the previous strainer head-loss qualification testing and will require the ANO-2 analyses to be significantly revised. Therefore, Entergy stated it needed additional time to revise the GL 2004-02 analyses in order to update the licensing basis.
By letter dated April 18, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML081120128), Entergy requested a second extension to the completion date for its corrective actions to be taken at ANO-2. Specifically, Entergy requested an extension until August 15, 2008, to complete the analyses to support GL 2004-02 resolution and update the ANO-2 licensing basis, and until September 15, 2008, to provide the final GL 2004-02 supplemental response.
By letter dated April 24, 2008 (ADAMS Accession No. ML081160051), Entergy requested a second extension to the completion date for its corrective actions to be taken at the Arkansas Nuclear One, Unit 1 (ANO-1). Entergy stated that it has completed the in-vessel downstream effects analysis and strainer head-loss report; however, the remainder of the ANO-1 analyses is not complete. Therefore, Entergy requested an 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 the first extension letter dated November 7, 2007, Entergy stated that actions have been taken to bring ANO-1 and ANO-2 into compliance with GL 2004-02, including replacing the sump screens with substantially larger sump strainers during the fall 2006 refueling outage for ANO-2 and during the spring 2007 refueling outage for ANO-1. In addition, Entergy stated that a containment buffer replacement was necessary to address chemical effects for ANO-2. By letter dated October 5, 2007, Entergy had requested a license amendment to support the replacement of the containment buffering agent during the spring 2008 refueling outage scheduled to begin on March 16, 2008. Consistent with the amendment request, Entergy requested an extension for ANO-2 to delay the completion of buffer replacement until restart following its spring 2008 refueling outage. Entergy stated that additional time was also needed to complete the sump analysis for ANO-1 and to change the sodium hydroxide concentration in the solution used for controlling the pH (potential of Hydrogen) in the containment pool.
Therefore, Entergy requested an extension for ANO-1 to complete these actions on the same schedule as the extension request for ANO-2 (i.e., prior to the restart of ANO-2 from its spring 2008 refueling outage).
In a letter dated December 21, 2007 (ADAMS Accession No. ML073520302), the NRC approved the first extension request for the completion of GL 2004-02 corrective actions for ANO-1 and ANO-2. Specifically, Entergy was to complete the specific corrective actions according to the following schedule:
Completion of the planned outage-related modifications specified above for ANO-2 (i.e., buffer replacement and insulation modifications) prior to the restart of ANO-2 from its upcoming refueling outage scheduled to begin on March 16,
- 2008, Completion of the buffer concentration change for ANO-1 by the end of April 2008, Completion of analyses for downstream effects in the reactor vessel and strainer head-loss reports by the end of April 2008, and Completion of final strainer certification/qualification calculations and licensing basis updates for Generic Safety Issue (GSI)-191 by the end of June 2008.
As described above, the NRC letter dated December 21, 2007, contained approval for ANO-1 to complete the analysis for downstream effects in the reactor vessel and a strainer head-loss report by the end of April 2008, and to complete the final strainer certification/qualification reports and update the licensing basis for GSI-191 by the end of June 2008.
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, and 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 and scheduler basis in its November 7, 2007, letter. In addition, Entergy has committed to the following:
For ANO-1, Entergy will complete analyses to support GL 2004-02 resolution (including ex-vessel downstream effects analysis) and update the ANO-1 licensing basis by June 30, 2008, and will provide the final supplemental response for ANO-1 by July 31, 2008, and For ANO-2, Entergy will complete analyses to support GL 2004-02 resolution and update the ANO-2 licensing basis by August 15, 2008, and will provide the final supplemental response for ANO-2 by September 15, 2008.
With regard to the second extension criterion, mitigative measures, compensatory measures and favorable conditions remain in effect in ANO-1 and ANO-2, as described in the December 21, 2007, NRC letter. In addition to the measures listed in the NRC letter, during a telephone conversation with the NRC staff on April 22, 2008, Entergy stated that it has completed the buffer concentration change for ANO-1. In its April 14, 2008, letter, Entergy stated it has completed the buffer replacement and removed the vast majority of the fibrous piping insulation and provided multiple banding to substantial portions of the calcium silicate insulation prior to the restart of ANO-2. The banding of the insulation decreases the vulnerability of the insulation to become debris during a loss-of-coolant accident scenario.
With regard to the third extension criterion, Entergy will have the following mitigative measure improvements in place for the requested extension period:
a change to the sodium hydroxide concentration for ANO-1 no later than spring
- 2008,
a change to the ANO-2 buffer from trisodium phosphate to sodium tetraborate, and modifications to insulation at ANO-2, including a reactor vessel head shroud insulation change (from Transco thermal wrap to reflective metal insulation),
fibrous insulation removal, and calcium silicate insulation banding.
Based on the licensee having satisfactorily addressed the extension criteria in NRC GL 2004-02 as discussed above:
- 1.
the NRC finds it is acceptable to extend the date for completion of ANO-1 analyses in support of the GL 2004-02 resolution (including ex-vessel downstream effects analysis) and for the update of the ANO-1 licensing basis to June 30, 2008. Entergy will provide the final GL 2004-02 supplemental response for ANO-1 by July 31, 2008. Should the time period for potential ANO-1 corrective actions be determined by Entergy to extend beyond June 30, 2008, Entergy will need to submit an additional extension request to the NRC, and
- 2.
the NRC finds it is acceptable to extend the completion date to August 15, 2008, for completion of ANO-2 analyses in support of the GL 2004-02 resolution and update of the ANO-2 licensing basis. In addition, Entergy will provide a final GL 2004-02 supplemental response for ANO-2 by September 15, 2008. Should the time period for potential ANO-2 corrective actions be determined by Entergy to extend beyond August 15, 2008, Entergy will need to submit an additional extension request to the NRC.
Entergy should complete its remaining GL 2004-02 corrective actions discussed above and update the ANO-1 and ANO-2 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 G. Hiltz, Branch Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-313 and 50-368 cc: See next page
a change to the ANO-2 buffer from trisodium phosphate to sodium tetraborate, and modifications to insulation at ANO-2, including a reactor vessel head shroud insulation change (from Transco thermal wrap to reflective metal insulation),
fibrous insulation removal, and calcium silicate insulation banding.
Based on the licensee having satisfactorily addressed the extension criteria in NRC GL 2004-02 as discussed above:
- 1.
the NRC finds it is acceptable to extend the date for completion of ANO-1 analyses in support of the GL 2004-02 resolution (including ex-vessel downstream effects analysis) and for the update of the ANO-1 licensing basis to June 30, 2008. Entergy will provide the final GL 2004-02 supplemental response for ANO-1 by July 31, 2008. Should the time period for potential ANO-1 corrective actions be determined by Entergy to extend beyond June 30, 2008, Entergy will need to submit an additional extension request to the NRC, and
- 2.
the NRC finds it is acceptable to extend the completion date to August 15, 2008, for completion of ANO-2 analyses in support of the GL 2004-02 resolution and update of the ANO-2 licensing basis. In addition, Entergy will provide a final GL 2004-02 supplemental response for ANO-2 by September 15, 2008. Should the time period for potential ANO-2 corrective actions be determined by Entergy to extend beyond August 15, 2008, Entergy will need to submit an additional extension request to the NRC.
Entergy should complete its remaining GL 2004-02 corrective actions discussed above and update the ANO-1 and ANO-2 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 G. Hiltz, Branch Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-313 and 50-368 cc: See next page DISTRIBUTION:
PUBLIC LPLIV R/F RidsAcrsAcnw&mMailCenter RidsNrrDorlLpl4 RidsNrrDssSsib RidsNrrLAGLappert RidsNrrPMAWang RidsOgcRp RidsRgn4MailCenter RTorres, NRR/DSS/SSIB ADAMS Accession No.: ML081210212
(*) concurrence via input memo OFFICE NRR/LPL4/PM NRR/LPL4/LA DSS/SSIB/BC*
NRR/LPL4/BC NAME AWang GLappert MScott (*)
THiltz DATE 4/30/08 4/30/08 04/29/08 4/30/08
OFFICIAL RECORD COPY
Arkansas Nuclear One (2/25/08) cc:
Senior Vice President Entergy Nuclear Operations P.O. Box 31995 Jackson, MS 39286-1995 Vice President, Oversight Entergy Nuclear Operations P.O. Box 31995 Jackson, MS 39286-1995 Senior Manager, Nuclear Safety
& Licensing Entergy Nuclear Operations P.O. Box 31995 Jackson, MS 39286-1995 Senior Vice President
& Chief Operating Officer Entergy Operations, Inc.
P.O. Box 31995 Jackson, MS 39286-1995 Associate General Counsel Entergy Nuclear Operations P.O. Box 31995 Jackson, MS 39286-1995 Manager, Licensing Entergy Operations, Inc.
Arkansas Nuclear One 1448 SR 333 Russellville, AR 72802 Section Chief, Division of Health Radiation Control Section Arkansas Department of Health and Human Services 4815 West Markham Street, Slot 30 Little Rock, AR 72205-3867 Section Chief, Division of Health Emergency Management Section Arkansas Department of Health and Human Services 4815 West Markham Street, Slot 30 Little Rock, AR 72205-3867 Pope County Judge Pope County Courthouse 100 W. Main Street Russellville, AR 72801 Senior Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 310 London, AR 72847 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064