ML073531095
| ML073531095 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 12/10/2007 |
| From: | Mims D C Arizona Public Service Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 102-05779-DCM/GAM, GL-04-002 | |
| Download: ML073531095 (13) | |
Text
Generic Letter 2004-02.AMS Dwight C. Mims Mail Station 7605 Palo Verde Nuclear Vice President Tel. 623-393-5403 P.O. Box 52034 Generating Station Regulatory Affairs and Plant Improvement Fax 623-393-6077 Phoenix, Arizona 85072-2034 102-05779-DCM/GAM December 10, 2007 Attn: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Dear Sirs:
Subject:
Palo Verde Nuclear Generating Station (PVNGS)Units 1, 2, and 3 Docket Nos. STN 50-528, 50-529, and 50-530 Request for Extension to Complete the Final Confirmatory Testing, Analysis and Validation of Containment Sump Strainers Associated with NRC Generic Letter 2004-02 By letter no. 102-05336, dated September 1, 2005, Arizona Public Service Company (APS) submitted to the NRC a response to Request No. 2 in Generic Letter (GL)2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." In that submittal, APS committed to actions that would address the issues identified in the GL, including the installation of new, larger containment sump strainers in PVNGS Units 1, 2, and 3, and the completion of actions needed to confirm the revised containment sump design analyses.
Completion dates for several commitments were subsequently updated in APS letters dated March 20, June 29, August 30, and October 12, 2006, and March 2, 2007. In addition, by letter dated December 13, 2006, the NRC approved an extension to install the larger sump strainers in Unit 2 during the spring 2008 refueling outage.APS has determined that the final confirmatory testing, analysis and validation of containment sump strainers for the PVNGS units will not be able to be completed by December 31, 2007, due to a number of issues including competing vendor resources on closure issues and various revisions to the guidance documents providing the methodologies for performing and validating these tests. Therefore, APS is requesting approval to complete the containment sump strainer confirmatory testing, analysis, and validation for PVNGS Units 1, 2, and 3 by June 30, 2008. This extension request is consistent with Case 2 in the November 8, 2007 NRC letter to the Nuclear Energy Institute (NEI). This request and justification are provided in Enclosure
- 1. Enclosure 2 contains the list of GL 2004-02 commitments and status or due dates.A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway 0 Comanche Peak 0 Diablo Canyon
- Palo Verde e South Texas Project
- Wolf Creek A 9 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Request for Extension Associated with NRC Generic Letter 2004-02 Page 2 Contingent on NRC approval, APS commits to complete the containment sump strainer confirmatory testing, analysis, and validation for PVNGS Units 1, 2, and 3 by June 30, 2008. APS commits to submit the information from containment sump strainer confirmatory testing, analysis and validation for PVNGS Units 1, 2 and 3 within 90 days of their completion (this will provide information not submitted with the GL 2004-02 supplemental response due by February 29, 2008).If you have any questions, please contact Glenn A. Michael at (623) 393-5750.I declare under penalty of perjury that the foregoing is true and correct.Executed on /,__/_1_/7 Sincerely, DCM/SAB/GAM/gat
Enclosures:
- 1. Request for Extension Associated with NRC Generic Letter 2004-02 2. List of Generic Letter 2004-02 Commitments with Status or Due Dates cc: E. E. Collins Jr.M. T. Markley G. G. Warnick NRC Region IV Regional Administrator NRC NRR Project Manager NRC Senior Resident Inspector for PVNGS Enclosure 1 Request for Extension Associated with NRC Generic Letter (GL) 2004-02 Enclosure 1 Request for Extension Associated with NRC Generic Letter (GL) 2004-02 Extension Requested Arizona Public Service Company (APS) is requesting approval to complete the GL 2004-02 containment sump strainer confirmatory testing, analysis and validation for PVNGS Units 1, 2, and 3 by June 30, 2008. This extension request is consistent with Case 2 in the November 8, 2007 NRC letter to the Nuclear Energy Institute (NEI). The period of the requested extension for Units 1 and 3 would be from December 31, 2007, until June 30, 2008. The period of the requested extension for Unit 2 would be from the expiration of the currently-approved extension (the end of the spring 2008 refueling outage, approximately May 15, 2008) until June 30, 2008.Background APS has aggressively pursued the completion of the design, procurement, installation of the new sump strainers, and the evaluation of all applicable issues. The new, larger containment sump strainers have been installed in PVNGS Unit 1, and installation in Unit 3 will be completed during the current refueling outage (before December 31, 2007). The new sump strainers will be installed in Unit 2 during the spring 2008 refueling outage, as allowed by the extension approved by the NRC in a letter to APS dated December 13, 2006.Criteria for Extension Requests By letter dated November 8, 2007, the NRC provided to the Nuclear Energy Institute (NEI) guidance to licensees for pressurized water reactor (PWR) plants for additional time to complete corrective actions for GL 2004-02 (Agencywide Documents Access and Management System accession no. ML073060581).
This guidance stated the following for Case 2: Case 2: Plants for which licensees have determined that testing and/or analyses will not be completed or are not likely to be completed by the end of 2007.Requests for extension under these circumstances should be submitted to the NRC as soon as the licensee believes the circumstances apply, not later than December 10, 2007. Because testing activities are scheduled for late 2007 and the first quarter of 2008, the NRC believes extensions needed in this situation will at most cover a few months. The NRC staff plans to review extension requests of this sort using the criteria of SECY-06-0078.
Among other things, these criteria call for the licensee to describe how mitigative measures taken by the licensee will minimize the risk of degraded safety system functions during the extension period. In addition to these criteria, licensees requesting an extension beyond June 30, 2008, should provide a quantitative risk assessment to help support its request and to inform the staff's review of that request.1 Enclosure 1 Request for Extension Associated with NRC Generic Letter (GL) 2004-02 SECY-06-0078 provided the following guidance: Proposed extensions to permit changes at the next outage of opportunity after December 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.For proposed extensions beyond several months, a licensee's 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.
Plant Specific technical/experimental plan Enclosure 2 provides the PVNGS plan, status, and schedule for completion of all elements in response to GL 2004-02.Mitigqative Measures The following mitigative measures will minimize the risk of degraded system functions during the extension period (until June 30, 2008): The new, larger containment sump strainers have been installed in PVNGS Unit 1, and installation in Unit 3 will be completed during the current refueling outage (before December 31, 2007). The new sump strainers will be installed in Unit 2 during the spring 2008 refueling outage (to be completed by approximately May 15, 2008), as allowed by the extension approved by the NRC in a letter to APS dated December 13, 2006." The new sump strainers have a surface area of approximately 3140 square feet compared with approximately 210 square feet of surface area in the old strainers.
- The new strainers have a nominal hole size of 1/12 inch compared with 1/8 inch for the old strainers.
2 Enclosure 1 Request for Extension Associated with NRC Generic Letter (GL) 2004-02" The installed Fiberfrax insulation, which is a significant debris source, has been removed from PVNGS Units 1 and 2, and is being removed from Unit 3 during the current refueling outage (before December 31, 2007). (Note: PVNGS uses reflective metallic insulation as the primary insulation for the nuclear steam supply system piping and vessels.)* Compensatory operator actions in response to Bulletin 2003-01, "Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized Water Reactors," have been implemented, as described in APS letter nos. 102-05236, dated March 25, 2005, and 102-05335, dated August 30, 2005.* Changes in programs and procedures to ensure and/or enhance the control of transportable debris (e.g., insulation, signs, and foreign materials) in containment have been implemented in all three units.In addition, the following favorable conditions exist at Palo Verde, Units 1, 2, and 3:* Although Palo Verde uses trisodium phosphate as a containment sump pool pH buffer, no calcium silicate insulation material is used in containment that might react to form calcium phosphate precipitate." The new strainer confirmatory head-loss testing, capture ratio verification and chemical effects margin validation have been preliminarily completed.
They show a head loss margin of greater than 4 feet at elevated LOCA temperatures.
It is expected that the final analyzed tests will verify the acceptability of new sump strainer design margins, without further modifications.
Based on the above, APS believes the risk of any potential degraded system functions due to completing the containment sump strainer confirmatory testing, analysis, and validation for PVNGS Units 1, 2, and 3 during the extension period (until June 30, 2008)is minimal.3 Enclosure 2 List of Generic Letter 2004-02 Commitments with Status or Due Dates Enclosure 2 List of Generic Letter 2004-02 Commitments (Changes from APS letter no. 102-05651, March 2, 2007, are in bold)GL 2004-02 REGULATORY COMMITMENT LATEST REVISED (from APS letter no. 102-05560 PREVIOUS DUE DATE or dated August 30, 2006) DUE DATE STATUS 1. Evaluate the recommendations contained in the December 31, Completed Westinghouse downstream effects evaluation for 2005 PVNGS and establish an implementation schedule for appropriate recommendations. (RCTSAI 2826236)2. Perform confirmatory head-loss testing of new As soon in June 30, 2008 strainer with plant specific debris to ensure an 2007 as adequate design. (RCTSAI 2826244) achievable, and no later than December 31, 2007 3. Verify that a capture ratio of 97% or higher can be As soon in June 30, 2008 achieved in the final design of the new sump screen 2007 as to ensure that the fuel evaluation contained in the achievable, Westinghouse downstream effects evaluation is and no later bounding. (RCTSAI 2826247) than December 31, 2007 4. Perform sump strainer structural evaluation to October 31, Completed ensure seismic and operational integrity. (RCTSAI 2006 2826250)5. Validate allocated margins for Chemical Effects in As soon in June 30, 2008 strainer head-loss to ensure an adequate design. 2007 as (RCTSAI 2826239) achievable, and no later than December 31, 2007 6. Perform a confirmatory containment latent debris June 30, 2006 Completed walkdown of PVNGS Units 1 and 3. (RCTSAI 2826259) [Note: The containment walkdown for transportable debris was completed in Unit 2 as stated in letter no. 102-05336, 911105.]1 Enclosure 2 List of Generic Letter 2004-02 Commitments (Changes from APS letter no. 102-05651, March 2, 2007, are in bold)GL 2004-02 REGULATORY COMMITMENT LATEST REVISED (from APS letter no. 102-05560 PREVIOUS DUE DATE or dated August 30, 2006) DUE DATE STATUS 7. Perform a confirmatory containment unqualified June 30, 2006 Completed coating walkdown of PVNGS Units 1 and 3.(RCTSAI 2826260) [Note: The containment walkdown for transportable debris was completed in Unit 2 as stated in letter no. 102-05336, 9/1/05.]8. Review the existing programmatic controls for November 30, Completed containment coatings identified in the response to 2006 GL 98-04, "Potential for Degradation of the Emergency Core Cooling System and the Containment Spray System after a Loss-of-Coolant Accident Because of Construction and Protective Coating Deficiencies and Foreign Material in Containment," for their adequacy. (RCTSAI 2826262)9. Review the existing programmatic and procedural November 30, Completed controls in place to prevent potentially transportable 2006 debris (insulation, signs and foreign material) in the containment building to ensure that the bounding assumptions in the design of the new strainers will be maintained. (RCTSAI 28262826263)
- 10. Implement in Unit 1 changes to programs and 1R13 refueling Completed procedures to ensure and/or enhance the control of outage transportable debris in containment. (RCTSAI (approx.2826264) May 31,2007)11. Implement in Unit 2 changes to programs and 2R13 refueling Completed procedures to ensure and/or enhance the control of outage transportable debris in containment. (RCTSAI (approx.2826267) Nov. 30, 2006)12. Implement in Unit 3 changes to programs and 3R1 3 refueling No Change procedures to ensure and/or enhance the control of outage transportable debris in containment. (RCTSAI (approx.2826269) Dec. 31,2007)2 Enclosure 2 List of Generic Letter 2004-02 Commitments (Changes from APS letter no. 102-05651, March 2, 2007, are in bold)GL 2004-02 REGULATORY COMMITMENT LATEST REVISED (from APS letter no. 102-05560 PREVIOUS DUE DATE or dated August 30, 2006) DUE DATE STATUS 13. Install larger sump strainers in PVNGS Unit 1. 1 R1 3 refueling Completed (RCTSAI 2826 277) outage (approx.May 31, 2007)14. Install larger sump strainers in PVNGS Unit 2. 2R14 refueling No change.(RCTSAI 2826278) outage (to begin no later than April 28, 2008)15. Install larger sump strainers in PVNGS Unit 3. 3R1 3 refueling No change.(RCTSAI 2826284) outage (approx.Dec. 31, 2007)16. Remove installed Fiberfrax insulation in PVNGS 1R13 refueling Completed Unit 1. (RCTSAI 2826282) outage (approx.May 31, 2007)17. Remove installed Fiberfrax insulation in PVNGS 2R13 refueling Completed Unit 2. (RCTSAI 2826283) outage (approx.Nov. 30, 2006)18. Remove installed Fiberfrax insulation in PVNGS 3R13 refueling No change.Unit 3. (RCTSAI 2826284) outage (approx.Dec. 31,2007)3 Enclosure 2 List of Generic Letter 2004-02 Commitments (Changes from APS letter no. 102-05651, March 2, 2007, are in bold)GL 2004-02 REGULATORY COMMITMENT LATEST REVISED (from APS letter no. 102-05560 PREVIOUS DUE DATE or dated August 30, 2006) DUE DATE STATUS 19. After plant specific strainer testing has been To be This item is completed and the Westinghouse downstream submitted closed to effects evaluation for PVNGS has been evaluated, along with the new APS will submit an update to the NRC to report the NRC RAI commitments validation of the allocated margins for chemical response as #20 and #21 effects and identify any recommendations from the soon in 2007 Westinghouse evaluation to be implemented.
as the results (RCTSAI 2826287) are available, and no later than December 31, 2007 20. Contingent on NRC approval, APS commits to New June 30, 2008 complete the containment sump strainer commitment confirmatory testing, analysis and validation for in this letter PVNGS Units 1, 2 and 3 by June 30, 2008.(RCTSAI 3106850)21.Submit the information from containment sump New September strainer confirmatory testing, analysis and commitment 28, 2008 validation for PVNGS Units 1, 2 and 3 within 90 in this letter days of their completion (this will provide information not submitted with the GL 2004-02 supplemental response due by February 29, 2008). (RCTSAI 3106852)References Arizona Public Service Companv Letters 1. Letter no. 102-05221, March 4, 2005, 90-Day Response to NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." 2. Letter no. 102-05236, March 25, 2005, Supplement to Responses to Bulletin 2003-01, "Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized Water Reactors," Regarding Operator Actions.4 Enclosure 2 List of Generic Letter 2004-02 Commitments (Changes from APS letter no. 102-05651, March 2, 2007, are in bold)3. Letter no. 102-05304, July 9, 2005, Response to NRC Request for Additional Information Related to Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." 4. Letter no. 102-05335, August 30, 2005, Responses to Request for Additional Information Related to Potential Operator Actions for Containment Sump Debris Blockage (NRC Bulletin 2003-01).5. Letter no. 102-05336, September 1, 2005, Response to Request No. 2 in NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." 6. Letter no. 102-05449, March 20, 2006, Revision to Commitment Dates Associated with NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." 7. Letter no. 102-05523, June 29, 2006, Revision to Commitment Dates Associated with NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." 8. Letter no. 102-05560, August 30, 2006, Revision to Commitment Date Associated with NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." 9. Letter no. 102-05584, October 12, 2006, Unit 2 -Request for Extension to Delay Implementation of Containment Sump Strainer Changes Associated with NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." 10. Letter no. 102-05651, March 2, 2007, Revision to Commitment Dates Associated with NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors".
NRC Letters to APS 1. Generic Letter 2004-02 dated September 13, 2004, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." 5 Enclosure 2 List of Generic Letter 2004-02 Commitments (Changes from APS letter no. 102-05651, March 2, 2007, are in bold)2. Letter dated June 2, 2005, Request for Additional Information (RAI) Related to Generic Letter 2004-02, "Potential Impact Of Debris Blockage On Emergency Sump Recirculation At Pressurized-Water Reactors." 3. Letter dated February 9, 2006, Request for Additional Information Re: Response to Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." 4. Letter dated March 28, 2006, Alternative Approach for Responding to the Nuclear Regulatory Commission Request for Additional Information Letter Re: Generic Letter 2004-02.5. Letter dated December 13, 2006, Unit 2 -Approval of Generic Letter 2004-02 Extension Request.6. Letter dated January 4, 2007, Alternative Approach for Responding to the Nuclear Regulatory Commission Request for Additional Information Letter Regarding Generic Letter 2004-02.6