ML082260504
| ML082260504 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 08/18/2008 |
| From: | Melanie Wong NRC/NRR/ADRO/DORL/LPLII-1 |
| To: | Tynan T Southern Nuclear Operating Co |
| wong melanie 301-415-2911 | |
| References | |
| GL-04-002, GSI-191, TAC MC4727, TAC MC4728 | |
| Download: ML082260504 (6) | |
Text
August 18, 2008 Mr. Tom E. Tynan Vice President - Vogtle Vogtle Electric Generating Plant 7821 River Road Waynesboro, GA 30830
SUBJECT:
VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 - GENERIC LETTER 2004-02, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED WATER REACTORS," EXTENSION REQUEST APPROVAL (TAC NOS. MC4727 AND MC4728)
Dear Mr. Tynan:
The U.S. Nuclear Regulatory Commission (NRC) staff evaluated the information provided in the Southern Nuclear Operating Company letter dated July 31, 2008 (Agencywide Documents Access and Management Systems (ADAMS) Accession No. ML082170487) supporting a request for an extension of the Vogtle Electric Generating Plant (VEGP), Units 1 and 2, sump clogging corrective actions due date as specified in an NRC letter dated May 29, 2008 (ADAMS Accession No. ML081490366). The NRC staff determined that, for VEGP, Units 1 and 2, it is acceptable to extend the due date for completion of chemical effects and downstream effects evaluations, as described in the enclosure, until August 29, 2008. Enclosed is the NRC staff evaluation.
Sincerely,
/RA/
Melanie C. Wong, Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425
Enclosure:
As Stated cc: w/encl See next page
ML082260504 OFFICE LPL2-1/PM LPL2-1/LA SSIB/BC LPL2-1/BC NAME RMartin GLappert MScott MWong DATE 08/18/08 08/15/08 08/12/08 8/18/08
EVALUATION OF EXTENSION REQUEST TO COMPLETE CORRECTIVE ACTIONS GENERIC SAFETY ISSUE-191, "ASSESSMENT OF DEBRIS ACCUMULATION ON PWR SUMP PUMP PERFORMANCE" GENERIC LETTER 2004-02, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED WATER REACTORS" VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 DOCKET NO. 50-424, 50-425 By letter dated July 31, 2008 to the U.S. Nuclear Regulatory Commission (NRC) (Agencywide Documents Access and Management System (ADAMS) Accession No. ML082170487),
Southern Nuclear Operating Company (SNC, the licensee), requested an extension to the Generic Letter (GL) 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors corrective action due date for Vogtle Electric Generating Plant (VEGP), Units 1 and 2. The stated intent of this extension was to allow additional time for review of the final hydraulic sizing report and to incorporate the results into the design documentation. SNC requested an extension to August 29, 2008, for completion of these activities.
The NRC previously approved an extension for completion of VEGP, Units 1 and 2 GL 2004-02 sump clogging corrective actions from the due date of December 31, 2007, until May 31, 2008 (NRC letter dated December 19, 2007, Adams Accession No. ML073520145).
By letters dated May 22, 2008 (Adams Accession No. ML081430616), SNC requested an additional extension in order to perform corrective actions associated with downstream effects and chemical effects evaluations and testing, the NRC approved an extension for completion of these corrective actions from the GL 2004-02 corrective actions due date of May 31, 2008, until July 31, 2008 (NRC letter dated May 29, 2008, Adams Accession No. ML081490366).
SNC explained in its July 31, 2008 letter that the request for an additional extension for chemical effects and downstream effects evaluations is due to testing scheduling and resource availability issues. The licensee stated that General Electric Hitachi (GEH) did not receive the final chemical effects summary report from the testing vendor (VUEZ) until July 25, 2008, causing a delay in issuance of the Vogtle final hydraulic sizing report. SNC also stated in its July 31, 2008 letter that its third party vendor (Alion) worked with SNC and other utilities involved in VUEZ testing to address NRC questions regarding VUEZ testing during preparation of the Vogtle chemical effects summary report.
SNC stated in its July 31, 2008 letter that the bases for the previous extension request letters dated December 7, 2007 (Adams Accession No. ML073440044), and May 22, 2008 (Adams Accession No.ML081430616), remain valid and that SNC has reasonable assurance that the new VEGP sump screens will perform their design basis function under the original design bases considerations. This extension request will allowSNC to complete the documentation updates required to support the GL 2004-02 considerations.
The NRC 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 emergency core cooling system (ECCS) and containment spray system (CSS) functions during the extension period.
The 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, SNC has provided a plant-specific technical/experimental plan, with milestones and schedules, to complete the GL 2004-02 corrective actions. The licensee-proposed plan for the remaining corrective actions has been previously summarized and referenced in the previous VEGP, Units 1 and 2 NRC extension approval letters cited above. The licensee stated in its July 31, 2008, letter that the chemical effects summary report was provided to GEH on July 25, 2008, and that GEH will expedite incorporation of the results and is expected to issue their final report to SNC by Aug 2, 2008.
With regard to the second extension criterion, the licensee stated in its letter dated December 7, 2007, that modifications, mitigation measures, compensatory measures, and/or favorable conditions are in effect at VEGP, Units 1 and 2, minimizing the risk of degraded ECCS and CSS functions during the extension period. The NRC staff evaluation of the previous extension request concluded that SNC had put mitigation measures in place at VEGP, Units 1 and 2 to adequately reduce risk for the previous requested extension period (July 31, 2008), as stated in the NRC extension approval letter dated May 29, 2008.
The NRC staff believes that SNC has a reasonable plan for VEGP, Units 1 and 2 that should result in the completion of final GL 2004-02 corrective actions that provide acceptable strainer function with adequate margin for uncertainties. SNC stated it has reasonable assurance that positive suction head margin is maintained throughout the anticipated design post-accident sump temperature range. The licensee also stated that preliminary numbers indicate a minimum of approximately 7.5 feet of margin. The additional time requested in the July 31, 2008, letter is short, and it 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 staff finds it is acceptable to extend the completion date for GL 2004-02 corrective actions associated with final downstream effects and chemical effects documentation, as described in this enclosure, for VEGP, Units 1 and 2 from July 31, 2008, to August 29, 2008. While the NRC accepts these dates as providing a reasonable allowance for contingencies regarding completion of remaining activities to address GL 2004-02, the NRC expects VEGP to place a high priority on completing remaining actions and updating the plants licensing bases as soon as possible.
In a phone conference on July 31, 2008, the licensee stated that VEGP, Units 1 and 2 are in compliance with the regulations cited in the Applicable Regulatory Requirements section of GL 2004-02 with respect to their existing licensing bases. The SNC commitment contained in its July 31, 2008, letter is for VEGP, Units 1 and 2 to be in compliance with its new licensing basis, once all remaining GL 2004-02 corrective actions are completed by August 29, 2008.
Principal Contributor: R. Torres Dated: August 18, 2008
Vogtle Electric Generating Plant, Units 1 & 2 cc:
Mr. Tom E. Tynan Vice President - Vogtle Vogtle Electric Generating Plant 7821 River Road Waynesboro, GA 30830 Mr. N. J. Stringfellow Manager, Licensing Southern Nuclear Operating Company, Inc.
P.O. Box 1295 Birmingham, AL 35201-1295 Mr. Jeffrey T. Gasser Executive Vice President Southern Nuclear Operating Company, Inc.
P.O. Box 1295 Birmingham, AL 35201-1295 Mr. Steven M. Jackson Senior Engineer - Power Supply Municipal Electric Authority of Georgia 1470 Riveredge Parkway, NW Atlanta, GA 30328-4684 Mr. Reece McAlister Executive Secretary Georgia Public Service Commission 244 Washington St., SW Atlanta, GA 30334 Mr. Harold Reheis, Director Department of Natural Resources 205 Butler Street, SE, Suite 1252 Atlanta, GA 30334 Attorney General Law Department 132 Judicial Building Atlanta, GA 30334 Mr. Laurence Bergen Oglethorpe Power Corporation 2100 East Exchange Place P.O. Box 1349 Tucker, GA 30085-1349 Arthur H. Domby, Esquire Troutman Sanders Nations Bank Plaza 600 Peachtree Street, NE Suite 5200 Atlanta, GA 30308-2216 Resident Inspector Vogtle Plant 8805 River Road Waynesboro, GA 30830 Office of the County Commissioner Burke County Commission Waynesboro, GA 30830 Mr. Bob Masse Resident Manager Oglethorpe Power Corporation Vogtle Electric Generating Plant 7821 River Road Waynesboro, GA 30830