ML073450594: Difference between revisions
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| number = ML073450594 | | number = ML073450594 | ||
| issue date = 12/13/2007 | | issue date = 12/13/2007 | ||
| title = | | title = Approval of Extension of Completion Dates for Corrective Actions of Generic Letter 2004-02 | ||
| author name = Lingam S | | author name = Lingam S | ||
| author affiliation = NRC/NRR/ADRO/DORL/LPLII-1 | | author affiliation = NRC/NRR/ADRO/DORL/LPLII-1 | ||
| addressee name = Matthews W | | addressee name = Matthews W | ||
| addressee affiliation = Virginia Electric & Power Co (VEPCO) | | addressee affiliation = Virginia Electric & Power Co (VEPCO) | ||
| docket = 05000280, 05000281, 05000305, 05000336, 05000338, 05000339, 05000423 | | docket = 05000280, 05000281, 05000305, 05000336, 05000338, 05000339, 05000423 | ||
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=Text= | =Text= | ||
{{#Wiki_filter:December 13, 2007 | {{#Wiki_filter:December 13, 2007 Mr. William R. Matthews Senior Vice President, Nuclear Operations Virginia Electric and Power Company Richmond, Virginia 23261 | ||
Mr. William R. Matthews Senior Vice President, Nuclear Operations Virginia Electric and Power Company Richmond, Virginia | |||
==SUBJECT:== | ==SUBJECT:== | ||
KEWAUNEE POWER STATION, MILLSTONE POWER STATION, UNITS 2 AND 3, NORTH ANNA POWER STATION, UNITS 1 AND 2, AND SURRY POWER STATION, UNITS 1 AND 2, REQUEST FOR EXTENSION OF COMPLETION DATES FOR GENERIC LETTER 2004-02 CORRECTIVE ACTIONS (TAC NOS. MC4691, MC4694, MC4695, MC4696, MC4697, MC4722 AND MC4723) | KEWAUNEE POWER STATION, MILLSTONE POWER STATION, UNITS 2 AND 3, NORTH ANNA POWER STATION, UNITS 1 AND 2, AND SURRY POWER STATION, UNITS 1 AND 2, REQUEST FOR EXTENSION OF COMPLETION DATES FOR GENERIC LETTER 2004-02 CORRECTIVE ACTIONS (TAC NOS. MC4691, MC4694, MC4695, MC4696, MC4697, MC4722 AND MC4723) | ||
==Dear Mr. Matthews:== | ==Dear Mr. Matthews:== | ||
By letter dated November 15, 2007, Dominion Energy Kewaunee, Inc., Dominion Nuclear Connecticut, Inc., and Virginia Electric and Power Company requested for an extension of the containment sump clogging corrective actions stated in Generic Letter (GL) 2004-02, | By letter dated November 15, 2007, Dominion Energy Kewaunee, Inc., Dominion Nuclear Connecticut, Inc., and Virginia Electric and Power Company requested for an extension of the containment sump clogging corrective actions stated in Generic Letter (GL) 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors, from December 31, 2007 to June 30, 2008 for Kewaunee Power Station (Kewaunee); from December 31, 2007 to November 30, 2008 for Millstone Power Station, Units 2 and 3 (Millstone 2 and 3), North Anna Power Station, Unit Nos. 1 and 2 (North Anna 1 and 2), and Surry Power Station, Unit No. 1 (Surry 1); and from March 8, 2008 to November 30, 2008 for Surry Power Station, Unit No. 2 (Surry 2). | ||
Based on the enclosed Nuclear Regulatory Commission staffs evaluation, we have extended the due date for completion of the GL 2004-02 corrective actions until May 31, 2008. | |||
Based on the enclosed Nuclear Regulatory Commission | Sincerely, | ||
/RA/ | |||
Sincerely, | Siva P. Lingam, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-305, 50-336, 50-423, 50-338, 50-339, 50-280 and 50-281 | ||
Docket Nos. 50-305, 50-336, 50-423, 50-338, 50-339, 50-280 and 50-281 | |||
==Enclosures:== | ==Enclosures:== | ||
: 1. Evaluation for Kewaunee | : 1. Evaluation for Kewaunee | ||
: 2. Evaluation for Millstone 2 and 3 3. Evaluation for North Anna 1 and 2 | : 2. Evaluation for Millstone 2 and 3 | ||
: 4. Evaluation for Surry 1 and 2 | : 3. Evaluation for North Anna 1 and 2 | ||
: 4. Evaluation for Surry 1 and 2 cc w/encl: See next page | |||
cc w/encl: | |||
As stated in SECY-06-0078, proposed extensions to permit changes at the next outage of opportunity after December 2007 may be granted based on the | ML073450594 *transmitted by memo dated OFFICE NRR/LPL2-1/PM NRR/LPL2-1/LA NRR/DSS/SSIB/BC NRR/LPL2-1/BC NAME SLingam MO=Brien MScott EMarinos DATE 12/12/07 12/12/07 12/5/07* 12/13/07 EXTENSION REQUEST FOR CONTAINMENT SUMP CORRECTIVE ACTIONS ASSOCIATED WITH GENERIC LETTER 2004-02 KEWANEE POWER STATION DOCKET NO. 50-305 In a letter dated November 15, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML073190553), Dominion Energy Kewaunee, Inc. (DEK) requested an extension to the corrective action due date of December 31, 2007, stated in Nuclear Regulatory Commission (NRC) Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors" (GL 2004-02), for the Kewaunee Power Station (Kewaunee). In its letter, DEK stated that it has taken actions toward bringing Kewaunee into compliance with GL 2004-02, including replacing the sump screens with substantially larger sump strainers during the fall 2006 refueling outage. | ||
: 1. the licensee has a plant-specific technical/experimental plan with milestones and schedules to address outstanding technical issues with enough margin to account for uncertainties, and | However, final documentation summarizing the results of recent strainer testing activities and the overall performance of Kewaunees sump strainer arrangement, and the revision of downstream effects evaluations have not been completed. Therefore, an extension to the compliance due date of December 31, 2007, was requested to allow time for completion of these activities. | ||
: 2. 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. | As stated in SECY-06-0078, proposed extensions to permit changes at the next outage of opportunity after December 2007 may be granted based on the licensees request, if the staff determines that: | ||
: 1. the licensee has a plant-specific technical/experimental plan with milestones and schedules to address outstanding technical issues with enough margin to account for uncertainties, and | |||
: 2. 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. | |||
In regard to the first criterion for approving an extension, DEK has a plant-specific plan, with milestones and schedules, to complete the Kewaunee GL 2004-02-required corrective actions and modifications by June 2008. Specifically, DEK plans to receive and approve its updated strainer performance documentation by April 2008, and to receive and approve a revised downstream effects evaluation by June 2008. | |||
Enclosure 1 | |||
The | In regard to the second criterion for approving an extension, DEK has stated that various modifications, mitigating measures, compensatory measures, and/or favorable conditions are in effect at Kewaunee, minimizing the risk of degraded ECCS and CSS functions during the extension period, including a large replacement sump strainer with a 769 sq. ft. surface area, and new debris interceptors installed around the strainer arrangement. | ||
After reviewing DEKs submittal, the NRC staff concludes that DEK has a plan to complete the remaining corrective actions and has compensatory measures in place. However, given the importance of reaching a prompt closure of GL 2004-02, the NRC expects DEK to complete GL 2004-02 corrective actions at Kewaunee by May 31, 2008. | |||
The NRC has confidence that DEKs plan, as described in the November 15, 2007 letter, will result in the installation of final GSI-191 modifications that provide acceptable strainer function with adequate margin for uncertainties. Further, the NRC has concluded that DEK has put mitigation measures in place to adequately reduce risk for an approximate 5-month extension period. | |||
However, the NRC finds that DEK has not made a convincing case why the remaining corrective actions cannot be accomplished by May 2008. Therefore, it is acceptable for DEK to complete final documentation summarizing the results of recent Kewaunee strainer testing activities and the overall performance of Kewaunees sump strainer arrangement, and also complete revision to the Kewaunee downstream effects evaluations by May 31, 2008. Should DEK not complete the Kewaunee corrective actions for GL 2004-02 by May 31, 2008, DEK will need to provide the NRC additional justification for the delay. | |||
EXTENSION REQUEST FOR CONTAINMENT SUMP CORRECTIVE ACTIONS ASSOCIATED WITH GENERIC LETTER 2004-02 MILLSTONE POWER STATION, UNITS 2 AND 3 DOCKET NOS. 50-336 AND 50-423 In a letter dated November 15, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML073190553), Dominion Nuclear Connecticut, Inc. (DNC) requested an extension to the corrective action due date of December 31, 2007, stated in Nuclear Regulatory Commission (NRC) Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors" (GL 2004-02), for the Millstone Power Station Unit 2 and Unit 3 (Millstone 2 and Millstone 3). In its letter, DNC stated that it has taken actions toward bringing Millstone 2 and Millstone 3 into compliance with GL 2004-02, including replacing the sump screens with substantially larger sump strainers during the fall 2006 refueling outage and the spring 2007 refueling outage, respectively. | |||
However, completion of the downstream effects evaluations and associated acceptance reviews for components, including the vessel and the fuel, have not been completed for the two units. In addition, chemical effects testing and evaluation, and associated acceptance reviews, have not been completed for the two units. DNC also stated that determinations will have to be made as to whether any additional actions may be required based on the results of the foregoing technical evaluations and testing. Therefore, an extension to the compliance due date of December 31, 2007, was requested for Millstone 2 and Millstone 3 to allow time for completion of these activities. | |||
As stated in SECY-06-0078, proposed extensions to permit changes at the next outage of opportunity after December 2007 may be granted based on the licensees request, if the staff determines that: | |||
: 1. the licensee has a plant-specific technical/experimental plan with milestones and schedules to address outstanding technical issues with enough margin to account for uncertainties, and | |||
: 2. 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. | |||
Enclosure 2 | |||
However, completion of the downstream effects evaluations and associated acceptance reviews for components, including the vessel and the fuel, have not been completed for the two units. In addition, chemical effects testing and evaluation, and associated acceptance reviews, have not been completed for the two units. DNC also stated that determinations will have to be made as to whether any additional actions may be required based on the results of the foregoing technical evaluations and testing. Therefore, an extension to the compliance due date of December 31, 2007, was requested for | |||
As stated in SECY-06-0078, proposed extensions to permit changes at the next outage of opportunity after December 2007 may be granted based on the | |||
: 1. the licensee has a plant-specific technical/experimental plan with milestones and schedules to address outstanding technical issues with enough margin to account for uncertainties, and | |||
: 2. 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 | |||
In regard to the first criterion for approving an extension, DNC has a plant-specific plan, with milestones and schedules, to complete the Millstone 2 and Millstone 3 GL 2004-02-required corrective actions and modifications by November, 30, 2008. Specifically, DNC plans to complete a revised downstream effects evaluations for components, including reactor vessel and fuel, by March 31, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by June 30, 2008. In addition, DNC plans to complete chemical effects evaluations and bench-top testing to determine likely precipitate formation and bounding quantities precipitates by March 31, 2008, complete reduced scale (head loss) testing to determine the effects of chemical precipitate formation, if required, by September 30, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by November 30, 2008. | |||
In regard to the second criterion for approving an extension, DNC has stated that various modifications, mitigating measures, compensatory measures, and/or favorable conditions are in effect at Millstone 2 and Millstone 3, minimizing the risk of degraded ECCS and CSS functions during the extension period, including large replacement sump strainers with a 6,000 sq. ft. | In regard to the second criterion for approving an extension, DNC has stated that various modifications, mitigating measures, compensatory measures, and/or favorable conditions are in effect at Millstone 2 and Millstone 3, minimizing the risk of degraded ECCS and CSS functions during the extension period, including large replacement sump strainers with a 6,000 sq. ft. | ||
surface area for Millstone 2, and a 5,000 sq. ft. surface area for Millstone 3, both with some margin for chemical effects. | surface area for Millstone 2, and a 5,000 sq. ft. surface area for Millstone 3, both with some margin for chemical effects. Further, DNC stated that for Millstone 2 it had replaced some calcium silicate insulation from the steam generator cavities that could contribute to a limiting strainer debris bed (so that the remaining calcium silicate insulation is located outside the loss-of-coolant accident (LOCA) zone of influence, jacketed to prevent damage from containment spray, and would not become submerged during an accident). DNC also stated that for Millstone 3 it had implemented a modification to delay the start time of the Recirculation Spray System (RSS) pumps using a Lo-Lo Refueling Water Storage Tank level switch rather than a timer to ensure that the replacement sump strainers are submerged prior to pump start (with the Millstone 3 RSS pumps being the only pumps that take suction from the sump during recirculation and long-term cooling). | ||
Further, DNC stated that for Millstone 2 it had replaced some | In regard to the third criterion for approving an extension, DNC has installed very large strainers in the containment sumps for both Millstone 2 and Millstone 3, and therefore, this criterion is considered to be met. | ||
DNC provided a risk evaluation for Millstone 2 and Millstone 3, which compared the increase in Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) from a large-break LOCA to total plant CDF and LERF risk values and showed that these values could be categorized as small in accordance with the criteria stated in Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis. | |||
replacement sump | After reviewing DNCs submittal, the NRC staff concludes that DNC has a plan to complete the remaining corrective actions and has compensatory measures in place. However, the plan is open-ended (based on the chemical effects hardware and/or procedural change decision point in November, 2008). Further, the NRC views the scope of the additional activities required to demonstrate compliance with GL 2004-02 as achievable by May 31, 2008. | ||
The NRC has confidence that DNCs plan, as described in the November 15, 2007 letter, will result in the installation of final GSI-191 modifications that provide acceptable strainer function with adequate margin for uncertainties. Further, the NRC has concluded that DNC has put mitigation measures in place to adequately reduce risk for an approximate 5-month extension period. However, the NRC finds that DNC has an open-ended plan, and has not made a | |||
In regard to the third criterion for approving an extension, DNC has installed very large strainers in | |||
the containment sumps for both Millstone 2 and Millstone 3, and therefore, | |||
DNC provided a risk evaluation for Millstone 2 and Millstone 3, which | |||
After reviewing | |||
The NRC has confidence that | |||
convincing case why the remaining Millstone 2 and Millstone 3 corrective actions for GL 2004-02 cannot be accomplished by May 2008. Given the importance of reaching a prompt closure of GL 2004-02, the NRC expects DNC to complete GL 2004-02 corrective actions at Millstone 2 and Millstone 3 by May 31, 2008. Should DNC not complete the Millstone 2 and Millstone 3 corrective actions for GL 2004-02 by May 31, 2008, DNC will need to provide the NRC additional justification for the delay. | |||
In | EXTENSION REQUEST FOR CONTAINMENT SUMP CORRECTIVE ACTIONS ASSOCIATED WITH GENERIC LETTER 2004-02 NORTH ANNA POWER STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-338 AND 50-339 In a letter dated November 15, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML073190553), Virginia Electric and Power Company (Dominion) requested an extension to the corrective action due date of December 31, 2007, stated in Nuclear Regulatory Commission (NRC) Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors" (GL 2004-02), for the North Anna Power Station Unit 2 and Unit 3 (North Anna 1 and North Anna 2). In its letter, Dominion stated that it has taken actions toward bringing North Anna 1 and North Anna 2 into compliance with GL 2004-02, including replacing the sump screens with substantially larger sump strainers during the fall 2007 refueling outage and the spring 2007 refueling outage, respectively. However, completion of the downstream effects evaluations and associated acceptance reviews for components, including the vessel and the fuel, have not been completed for the two units. In addition, chemical effects testing and evaluation, and associated acceptance reviews, have not been completed for the two units. Dominion also stated that determinations will have to be made as to whether any additional actions may be required based on the results of the foregoing technical evaluations and testing. Therefore, an extension to the compliance due date of December 31, 2007, was requested for North Anna 1 and North Anna 2 to allow time for completion of these activities. | ||
As stated in SECY-06-0078, proposed extensions to permit changes at the next outage of opportunity after December 2007 may be granted based on the licensees request, if the staff determines that: | |||
: 1. the licensee has a plant-specific technical/experimental plan with milestones and schedules to address outstanding technical issues with enough margin to account for uncertainties, and | |||
: 2. 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. | |||
Enclosure 3 | |||
In regard to the first criterion for approving an extension, Dominion has a plant-specific plan, with milestones and schedules, to complete the North Anna 1 and North Anna 2 GL 2004-02-required corrective actions and modifications by November 30, 2008. Specifically, Dominion plans to complete a revised downstream effects evaluations for components, including reactor vessel and fuel, by March 31, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by June 30, 2008. In addition Dominion plans to complete chemical effects evaluations and bench-top testing to determine likely precipitate formation and bounding quantities precipitates by March 31, 2008, complete reduced scale (head loss) testing to determine the effects of chemical precipitate formation, if required, by September 30, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by November 30, 2008. | |||
In regard to the second criterion for approving an extension, Dominion has stated that various modifications, mitigating measures, compensatory measures, and/or favorable conditions are in effect at North Anna 1 and North Anna 2, minimizing the risk of degraded ECCS and CSS functions during the extension period, including large replacement sump strainers with a total of 6,400 sq. ft. surface area for North Anna 1 and a total of 6,300 sq. ft. surface area for North Anna 2. | In regard to the second criterion for approving an extension, Dominion has stated that various modifications, mitigating measures, compensatory measures, and/or favorable conditions are in effect at North Anna 1 and North Anna 2, minimizing the risk of degraded ECCS and CSS functions during the extension period, including large replacement sump strainers with a total of 6,400 sq. ft. surface area for North Anna 1 and a total of 6,300 sq. ft. surface area for North Anna 2. | ||
Dominion also stated that for North Anna 2, it had either removed or replaced the Microtherm insulation within the containment, and for North Anna 1 and North Anna 2, it had either removed | Dominion also stated that for North Anna 2, it had either removed or replaced the Microtherm insulation within the containment, and for North Anna 1 and North Anna 2, it had either removed or replaced the calcium silicate insulation in the stream generator and pressurizer rooms. | ||
Dominion further stated that it conducted various modifications to ensure strainer submergence. | |||
or replaced | In regard to the third criterion for approving an extension, Dominion has installed very large strainers in the containment sumps for both North Anna 1 and North Anna 2, and therefore, this criterion is considered to be met. | ||
Dominion provided a risk evaluation for North Anna 1 and North Anna 2, which compared the increase in Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) from a large-break LOCA to total plant CDF and LERF risk values and showed that these values could be categorized as small in accordance with the criteria stated in Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis. | |||
In regard to the third criterion for approving an extension, Dominion has installed very large strainers in the containment sumps for both North Anna 1 and North Anna 2, and therefore, this criterion is considered to be met. | After reviewing Dominions submittal, the NRC staff concludes that Dominion has a plan to complete the remaining corrective actions and has compensatory measures in place. However, the plan is open-ended (based on the chemical effects hardware and/or procedural change decision point in November, 2008). Further, the NRC views the scope of the additional activities required to demonstrate compliance with GL 2004-02 as achievable by May 31, 2008. | ||
The NRC has confidence that Dominions plan, as described in the November 15, 2007 letter, will result in the installation of final GSI-191 modifications that provide acceptable strainer function with adequate margin for uncertainties. Further, the NRC has concluded that Dominion has put mitigation measures in place to adequately reduce risk for an approximate 5-month extension period. However, the NRC finds that Dominion has an open-ended plan, and has not made a convincing case why the remaining North Anna 1 and North Anna 2 corrective actions for GL 2004-02 cannot be accomplished by May 2008. Given the importance of reaching a prompt closure of GL 2004-02, the NRC expects Dominion to complete GL 2004-02 corrective actions at North Anna 1 and North Anna 2 by May 31, 2008. Should Dominion not complete the North Anna 1 and North Anna 2 corrective actions for GL 2004-02 by May 31, 2008, Dominion will need to provide the NRC additional justification for the delay. | |||
EXTENSION REQUEST FOR CONTAINMENT SUMP CORRECTIVE ACTIONS ASSOCIATED WITH GENERIC LETTER 2004-02 SURRY POWER STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-280 AND 50-281 In a letter dated November 15, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML073190553), Virginia Electric and Power Company (Dominion) requested an extension to the corrective action due date of December 31, 2007, stated in Nuclear Regulatory Commission (NRC) Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors" (GL 2004-02), for the Surry Power Station Unit 2 and Unit 3 (Surry 1 and Surry 2). In its letter, Dominion stated that it has taken actions toward bringing Surry 1 and Surry 2 into compliance with GL 2004-02, including replacing the sump screens with substantially larger sump strainers during the fall 2007 refueling outage and the fall 2006 refueling outage respectively. However, completion of the downstream effects evaluations and associated acceptance reviews for components, including the vessel and the fuel, have not been completed for the two units. In addition, chemical effects testing and evaluation, and associated acceptance reviews, have not been completed for the two units. Dominion also stated that determinations will have to be made as to whether any additional actions may be required based on the results of the foregoing technical evaluations and testing. Therefore, an extension to the compliance due date of December 31, 2007, was requested for Surry 1 and Surry 2 to allow time for completion of these activities. | |||
As stated in SECY-06-0078, proposed extensions to permit changes at the next outage of opportunity after December 2007 may be granted based on the licensees request, if the staff determines that: | |||
: 1. the licensee has a plant-specific technical/experimental plan with milestones and schedules to address outstanding technical issues with enough margin to account for uncertainties, and | |||
: 2. 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. | |||
Enclosure 4 | |||
EXTENSION REQUEST FOR CONTAINMENT SUMP CORRECTIVE ACTIONS ASSOCIATED WITH GENERIC LETTER 2004-02 SURRY POWER STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-280 AND 50-281 In a letter dated November 15, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML073190553), Virginia Electric and Power Company (Dominion) requested an extension to the corrective action due date of December 31, 2007, stated in Nuclear Regulatory Commission (NRC) Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors" (GL 2004-02), for the Surry Power Station Unit 2 and Unit 3 (Surry 1 and Surry 2). In its letter, Dominion stated that it has taken actions toward bringing Surry 1 and Surry 2 into compliance with GL 2004-02, including replacing the sump screens with substantially larger sump strainers during the fall 2007 refueling outage and the fall 2006 refueling outage respectively. However, completion of the downstream effects evaluations and associated acceptance reviews for components, including the vessel and the fuel, have not been completed for the two units. In addition, chemical effects testing and evaluation, and associated acceptance reviews, have not been completed for the two units. | |||
Dominion also | |||
As stated in SECY-06-0078, proposed extensions to permit changes at the next outage of opportunity after December 2007 may be granted based on the | |||
: 1. the licensee has a plant-specific technical/experimental plan with milestones and schedules to address outstanding technical issues with enough margin to account for uncertainties, and | |||
: 2. 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 | |||
In regard to the first criterion for approving an extension, Dominion has a plant-specific plan, with milestones and schedules, to complete the Surry 1 and Surry 2 GL 2004-02-required corrective actions and modifications by November 30, 2008. Specifically, Dominion plans to complete a revised downstream effects evaluations for components, including reactor vessel and fuel, by March 31, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by June 30, 2008. In addition, Dominion plans to complete chemical effects evaluations and bench-top testing to determine likely precipitate formation and bounding quantities precipitates by March 31, 2008, complete reduced scale (head loss) testing to determine the effects of chemical precipitate formation, if required, by September 30, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by November 30, 2008. | |||
In regard to the second criterion for approving an extension, Dominion has stated that various modifications, mitigating measures, compensatory measures, and/or favorable conditions are in effect at Surry 1 and Surry 2, minimizing the risk of degraded ECCS and CSS functions during the extension period, including large replacement sump strainers with a total of 8,400 sq. ft. surface area for Surry 1 and a total of approximately 3,500 sq. ft. surface area for Surry 2 (the remaining approximate 5, 000 sq. ft. of strainer surface area is to be installed in the spring 2008 Surry 2 refueling outage under an NRC approved extension). Dominion also stated that for Surry 2 it had modified the Inside Recirculation Spray (IRS) pumps start signal to ensure strainer submergence. | In regard to the second criterion for approving an extension, Dominion has stated that various modifications, mitigating measures, compensatory measures, and/or favorable conditions are in effect at Surry 1 and Surry 2, minimizing the risk of degraded ECCS and CSS functions during the extension period, including large replacement sump strainers with a total of 8,400 sq. ft. surface area for Surry 1 and a total of approximately 3,500 sq. ft. surface area for Surry 2 (the remaining approximate 5, 000 sq. ft. of strainer surface area is to be installed in the spring 2008 Surry 2 refueling outage under an NRC approved extension). Dominion also stated that for Surry 2 it had modified the Inside Recirculation Spray (IRS) pumps start signal to ensure strainer submergence. | ||
Further, Dominion stated that for Surry 2 it had added a time delay to the Outside Recirculation Spray pumps start signal to reduce the load impact on the diesel generators and to allow sufficient time for the IRS pumps piping to fill and attain stable | Further, Dominion stated that for Surry 2 it had added a time delay to the Outside Recirculation Spray pumps start signal to reduce the load impact on the diesel generators and to allow sufficient time for the IRS pumps piping to fill and attain stable operation. Dominion stated that was installing the same modifications for Surry 1 during its fall 2007 refueling outage. | ||
In regard to the third criterion for approving an extension, Dominion has installed very large strainers in the containment sumps for both Surry 1 and Surry 2, and therefore, this criterion is considered to be met. | |||
In regard to the third criterion for approving an extension, Dominion has installed very large strainers in the containment sumps for both Surry 1 and Surry 2, and therefore, this criterion is considered to be met. | Dominion provided a risk evaluation for Surry 1 and Surry 2 which compared the increase in Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) from a large-break LOCA to total plant CDF and LERF risk values and showed that these values could be categorized as small in accordance with the criteria stated in Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis. | ||
After reviewing Dominions submittal, the NRC staff concludes that Dominion has a plan to complete the remaining corrective actions and has compensatory measures in place. However, the plan is open-ended (based on the chemical effects hardware and/or procedural change decision point in November, 2008). Further, the NRC views the scope of the additional activities required to demonstrate compliance with GL 2004-02 as achievable by May 31, 2008. | |||
Dominion provided a risk evaluation for Surry 1 and Surry 2 which compared the increase in Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) from a large-break LOCA to total plant CDF and LERF risk values and showed that these values could be categorized as | The NRC has confidence that Dominions plan, as described in the November 15, 2007 letter, will result in the installation of final GSI-191 modifications that provide acceptable strainer function with adequate margin for uncertainties. Further, the NRC has concluded that Dominion has put mitigation measures in place to adequately reduce risk for an approximate five-month extension period. However, the NRC finds that Dominion has an open-ended plan, and has not made a convincing case why the remaining Surry 1 and Surry 2 corrective actions for GL 2004-02 cannot | ||
Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis. | |||
After reviewing | |||
The NRC has confidence that | |||
be accomplished by May 2008. Given the importance of reaching a prompt closure of GL 2004-02, the NRC expects Dominion to complete GL 2004-02 corrective actions at Surry 1 and Surry 2 by May 31, 2008. Should Dominion not complete the Surry 1 and Surry 2 corrective actions for GL 2004-02 by May 31, 2008, Dominion will need to provide the NRC additional justification for the delay. | |||
Resident | Kewaunee Power Station, Millstone Power Station, Unit Nos. 2 and 3, North Anna Power Station, Unit Nos. 1 and 2, and Surry Power Station, Unit Nos. 1 & 2 cc: | ||
Mr. David A. Christian Office of the Attorney General President and Chief Nuclear Officer Commonwealth of Virginia Virginia Electrical and Power Company 900 East Main Street Innsbrook Technical Center Richmond, Virginia 23219 5000 Dominion Boulevard Glen Allen, VA 23060-6711 Mr. Chris L. Funderburk, Director Nuclear Licensing & Operations Support Ms. Lillian M. Cuoco, Esq. Dominion Resources Services, Inc. | |||
Senior Counsel Innsbrook Technical Center Dominion Resources Services, Inc. 5000 Dominion Blvd. | |||
Building 475, 5th Floor Glen Allen, Virginia 23060-6711 Rope Ferry Road Waterford, Connecticut 06385 Mr. C. Lee Lintecum County Administrator Mr. Donald E. Jernigan Louisa County Site Vice President Post Office Box 160 Surry Power Station Louisa, Virginia 23093 Virginia Electric and Power Company 5570 Hog Island Road Old Dominion Electric Cooperative Surry, Virginia 23883-0315 4201 Dominion Blvd. | |||
Glen Allen, Virginia 23060 Senior Resident Inspector Surry Power Station Senior Resident Inspector U. S. Nuclear Regulatory Commission North Anna Power Station 5850 Hog Island Road U. S. Nuclear Regulatory Commission Surry, Virginia 23883 P. O. Box 490 Mineral, Virginia 23117 Chairman Board of Supervisors of Surry County Mr. Daniel G. Stoddard Surry County Courthouse Site Vice President Surry, Virginia 23683 North Anna Power Station Virginia Electric and Power Company Dr. W. T. Lough Post Office Box 402 Virginia State Corporation Commission Mineral, Virginia 23117-0402 Division of Energy Regulation Post Office Box 1197 Mr. William R. Matthews Richmond, Virginia 23218 Senior Vice President, Nuclear Operations Virginia Electrical and Power Company Dr. Robert B. Stroube, MD, MPH Innsbrook Technical Center State Health Commissioner 5000 Dominion Boulevard Office of the Commissioner Glen Allen, VA 23060-6711 Virginia Department of Health Post Office Box 2448 Richmond, Virginia 23218 | |||
Mr. Thomas L. Breene Dominion Energy Kewaunee, Inc. | Kewaunee Power Station, Millstone Power Station, Unit Nos. 2 and 3, North Anna Power Station, Unit Nos. 1 and 2, and Surry Power Station, Unit Nos. 1 & 2 cc: | ||
Kewaunee Power Station N490 Highway 42 Kewaunee, WI | Edward L. Wilds, Jr., Ph.D. Mr. Joseph Roy Director, Division of Radiation Director of Operations Department of Environmental Massachusetts Municipal Wholesale Protection Electric Company 79 Elm Street P.O. Box 426 Hartford, CT 06106-5127 Ludlow, MA 01056 Regional Administrator, Region I Mr. William D. Bartron U.S. Nuclear Regulatory Commission Licensing Supervisor 475 Allendale Road Dominion Nuclear Connecticut, Inc. | ||
King of Prussia, PA 19406 Building 475, 5th Floor Roper Ferry Road First Selectmen Waterford, CT 06385 Town of Waterford 15 Rope Ferry Road Mr. J. Alan Price Waterford, CT 06385 Site Vice President Dominion Nuclear Connecticut, Inc. | |||
Charles Brinkman, Director Building 475, 5th Floor Washington Operations Nuclear Services Rope Ferry Road Westinghouse Electric Company Waterford, CT 06385 12300 Twinbrook Pkwy, Suite 330 Rockville, MD 20852 Ms. Leslie N. Hartz Dominion Energy Kewaunee, Inc. | |||
Senior Resident Inspector Kewaunee Power Station Millstone Power Station N 490 Highway 42 c/o U.S. Nuclear Regulatory Commission Kewaunee, WI 54216 P. O. Box 513 Niantic, CT 06357 Resident Inspectors Office U. S. Nuclear Regulatory Commission Mr. J. W. "Bill" Sheehan N490 Highway 42 Co-Chair NEAC Kewaunee, WI 54216-9510 19 Laurel Crest Drive Waterford, CT 06385 Mr. Thomas L. Breene Dominion Energy Kewaunee, Inc. | |||
Ms. Nancy Burton Kewaunee Power Station 147 Cross Highway N490 Highway 42 Redding Ridge, CT 00870 Kewaunee, WI 54216 Mr. Evan W. Woollacott Co-Chair Nuclear Energy Advisory Council 128 Terrys Plain Road Simsbury, CT 06070}} |
Latest revision as of 08:34, 13 March 2020
ML073450594 | |
Person / Time | |
---|---|
Site: | Millstone, Kewaunee, Surry, North Anna ![]() |
Issue date: | 12/13/2007 |
From: | Siva Lingam NRC/NRR/ADRO/DORL/LPLII-1 |
To: | Matthews W Virginia Electric & Power Co (VEPCO) |
Lingam, Siva NRR/DORL 415-1564 | |
References | |
GL-04-002, TAC MC4691, TAC MC4694, TAC MC4695, TAC MC4696, TAC MC4697, TAC MC4722, TAC MC4723 | |
Download: ML073450594 (15) | |
Text
December 13, 2007 Mr. William R. Matthews Senior Vice President, Nuclear Operations Virginia Electric and Power Company Richmond, Virginia 23261
SUBJECT:
KEWAUNEE POWER STATION, MILLSTONE POWER STATION, UNITS 2 AND 3, NORTH ANNA POWER STATION, UNITS 1 AND 2, AND SURRY POWER STATION, UNITS 1 AND 2, REQUEST FOR EXTENSION OF COMPLETION DATES FOR GENERIC LETTER 2004-02 CORRECTIVE ACTIONS (TAC NOS. MC4691, MC4694, MC4695, MC4696, MC4697, MC4722 AND MC4723)
Dear Mr. Matthews:
By letter dated November 15, 2007, Dominion Energy Kewaunee, Inc., Dominion Nuclear Connecticut, Inc., and Virginia Electric and Power Company requested for an extension of the containment sump clogging corrective actions stated in Generic Letter (GL) 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors, from December 31, 2007 to June 30, 2008 for Kewaunee Power Station (Kewaunee); from December 31, 2007 to November 30, 2008 for Millstone Power Station, Units 2 and 3 (Millstone 2 and 3), North Anna Power Station, Unit Nos. 1 and 2 (North Anna 1 and 2), and Surry Power Station, Unit No. 1 (Surry 1); and from March 8, 2008 to November 30, 2008 for Surry Power Station, Unit No. 2 (Surry 2).
Based on the enclosed Nuclear Regulatory Commission staffs evaluation, we have extended the due date for completion of the GL 2004-02 corrective actions until May 31, 2008.
Sincerely,
/RA/
Siva P. Lingam, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-305, 50-336, 50-423, 50-338, 50-339, 50-280 and 50-281
Enclosures:
- 1. Evaluation for Kewaunee
- 2. Evaluation for Millstone 2 and 3
- 3. Evaluation for North Anna 1 and 2
- 4. Evaluation for Surry 1 and 2 cc w/encl: See next page
ML073450594 *transmitted by memo dated OFFICE NRR/LPL2-1/PM NRR/LPL2-1/LA NRR/DSS/SSIB/BC NRR/LPL2-1/BC NAME SLingam MO=Brien MScott EMarinos DATE 12/12/07 12/12/07 12/5/07* 12/13/07 EXTENSION REQUEST FOR CONTAINMENT SUMP CORRECTIVE ACTIONS ASSOCIATED WITH GENERIC LETTER 2004-02 KEWANEE POWER STATION DOCKET NO. 50-305 In a letter dated November 15, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML073190553), Dominion Energy Kewaunee, Inc. (DEK) requested an extension to the corrective action due date of December 31, 2007, stated in Nuclear Regulatory Commission (NRC) Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors" (GL 2004-02), for the Kewaunee Power Station (Kewaunee). In its letter, DEK stated that it has taken actions toward bringing Kewaunee into compliance with GL 2004-02, including replacing the sump screens with substantially larger sump strainers during the fall 2006 refueling outage.
However, final documentation summarizing the results of recent strainer testing activities and the overall performance of Kewaunees sump strainer arrangement, and the revision of downstream effects evaluations have not been completed. Therefore, an extension to the compliance due date of December 31, 2007, was requested to allow time for completion of these activities.
As stated in SECY-06-0078, proposed extensions to permit changes at the next outage of opportunity after December 2007 may be granted based on the licensees request, if the staff determines that:
- 1. the licensee has a plant-specific technical/experimental plan with milestones and schedules to address outstanding technical issues with enough margin to account for uncertainties, and
- 2. 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.
In regard to the first criterion for approving an extension, DEK has a plant-specific plan, with milestones and schedules, to complete the Kewaunee GL 2004-02-required corrective actions and modifications by June 2008. Specifically, DEK plans to receive and approve its updated strainer performance documentation by April 2008, and to receive and approve a revised downstream effects evaluation by June 2008.
Enclosure 1
In regard to the second criterion for approving an extension, DEK has stated that various modifications, mitigating measures, compensatory measures, and/or favorable conditions are in effect at Kewaunee, minimizing the risk of degraded ECCS and CSS functions during the extension period, including a large replacement sump strainer with a 769 sq. ft. surface area, and new debris interceptors installed around the strainer arrangement.
After reviewing DEKs submittal, the NRC staff concludes that DEK has a plan to complete the remaining corrective actions and has compensatory measures in place. However, given the importance of reaching a prompt closure of GL 2004-02, the NRC expects DEK to complete GL 2004-02 corrective actions at Kewaunee by May 31, 2008.
The NRC has confidence that DEKs plan, as described in the November 15, 2007 letter, will result in the installation of final GSI-191 modifications that provide acceptable strainer function with adequate margin for uncertainties. Further, the NRC has concluded that DEK has put mitigation measures in place to adequately reduce risk for an approximate 5-month extension period.
However, the NRC finds that DEK has not made a convincing case why the remaining corrective actions cannot be accomplished by May 2008. Therefore, it is acceptable for DEK to complete final documentation summarizing the results of recent Kewaunee strainer testing activities and the overall performance of Kewaunees sump strainer arrangement, and also complete revision to the Kewaunee downstream effects evaluations by May 31, 2008. Should DEK not complete the Kewaunee corrective actions for GL 2004-02 by May 31, 2008, DEK will need to provide the NRC additional justification for the delay.
EXTENSION REQUEST FOR CONTAINMENT SUMP CORRECTIVE ACTIONS ASSOCIATED WITH GENERIC LETTER 2004-02 MILLSTONE POWER STATION, UNITS 2 AND 3 DOCKET NOS. 50-336 AND 50-423 In a letter dated November 15, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML073190553), Dominion Nuclear Connecticut, Inc. (DNC) requested an extension to the corrective action due date of December 31, 2007, stated in Nuclear Regulatory Commission (NRC) Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors" (GL 2004-02), for the Millstone Power Station Unit 2 and Unit 3 (Millstone 2 and Millstone 3). In its letter, DNC stated that it has taken actions toward bringing Millstone 2 and Millstone 3 into compliance with GL 2004-02, including replacing the sump screens with substantially larger sump strainers during the fall 2006 refueling outage and the spring 2007 refueling outage, respectively.
However, completion of the downstream effects evaluations and associated acceptance reviews for components, including the vessel and the fuel, have not been completed for the two units. In addition, chemical effects testing and evaluation, and associated acceptance reviews, have not been completed for the two units. DNC also stated that determinations will have to be made as to whether any additional actions may be required based on the results of the foregoing technical evaluations and testing. Therefore, an extension to the compliance due date of December 31, 2007, was requested for Millstone 2 and Millstone 3 to allow time for completion of these activities.
As stated in SECY-06-0078, proposed extensions to permit changes at the next outage of opportunity after December 2007 may be granted based on the licensees request, if the staff determines that:
- 1. the licensee has a plant-specific technical/experimental plan with milestones and schedules to address outstanding technical issues with enough margin to account for uncertainties, and
- 2. 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.
Enclosure 2
In regard to the first criterion for approving an extension, DNC has a plant-specific plan, with milestones and schedules, to complete the Millstone 2 and Millstone 3 GL 2004-02-required corrective actions and modifications by November, 30, 2008. Specifically, DNC plans to complete a revised downstream effects evaluations for components, including reactor vessel and fuel, by March 31, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by June 30, 2008. In addition, DNC plans to complete chemical effects evaluations and bench-top testing to determine likely precipitate formation and bounding quantities precipitates by March 31, 2008, complete reduced scale (head loss) testing to determine the effects of chemical precipitate formation, if required, by September 30, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by November 30, 2008.
In regard to the second criterion for approving an extension, DNC has stated that various modifications, mitigating measures, compensatory measures, and/or favorable conditions are in effect at Millstone 2 and Millstone 3, minimizing the risk of degraded ECCS and CSS functions during the extension period, including large replacement sump strainers with a 6,000 sq. ft.
surface area for Millstone 2, and a 5,000 sq. ft. surface area for Millstone 3, both with some margin for chemical effects. Further, DNC stated that for Millstone 2 it had replaced some calcium silicate insulation from the steam generator cavities that could contribute to a limiting strainer debris bed (so that the remaining calcium silicate insulation is located outside the loss-of-coolant accident (LOCA) zone of influence, jacketed to prevent damage from containment spray, and would not become submerged during an accident). DNC also stated that for Millstone 3 it had implemented a modification to delay the start time of the Recirculation Spray System (RSS) pumps using a Lo-Lo Refueling Water Storage Tank level switch rather than a timer to ensure that the replacement sump strainers are submerged prior to pump start (with the Millstone 3 RSS pumps being the only pumps that take suction from the sump during recirculation and long-term cooling).
In regard to the third criterion for approving an extension, DNC has installed very large strainers in the containment sumps for both Millstone 2 and Millstone 3, and therefore, this criterion is considered to be met.
DNC provided a risk evaluation for Millstone 2 and Millstone 3, which compared the increase in Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) from a large-break LOCA to total plant CDF and LERF risk values and showed that these values could be categorized as small in accordance with the criteria stated in Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis.
After reviewing DNCs submittal, the NRC staff concludes that DNC has a plan to complete the remaining corrective actions and has compensatory measures in place. However, the plan is open-ended (based on the chemical effects hardware and/or procedural change decision point in November, 2008). Further, the NRC views the scope of the additional activities required to demonstrate compliance with GL 2004-02 as achievable by May 31, 2008.
The NRC has confidence that DNCs plan, as described in the November 15, 2007 letter, will result in the installation of final GSI-191 modifications that provide acceptable strainer function with adequate margin for uncertainties. Further, the NRC has concluded that DNC has put mitigation measures in place to adequately reduce risk for an approximate 5-month extension period. However, the NRC finds that DNC has an open-ended plan, and has not made a
convincing case why the remaining Millstone 2 and Millstone 3 corrective actions for GL 2004-02 cannot be accomplished by May 2008. Given the importance of reaching a prompt closure of GL 2004-02, the NRC expects DNC to complete GL 2004-02 corrective actions at Millstone 2 and Millstone 3 by May 31, 2008. Should DNC not complete the Millstone 2 and Millstone 3 corrective actions for GL 2004-02 by May 31, 2008, DNC will need to provide the NRC additional justification for the delay.
EXTENSION REQUEST FOR CONTAINMENT SUMP CORRECTIVE ACTIONS ASSOCIATED WITH GENERIC LETTER 2004-02 NORTH ANNA POWER STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-338 AND 50-339 In a letter dated November 15, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML073190553), Virginia Electric and Power Company (Dominion) requested an extension to the corrective action due date of December 31, 2007, stated in Nuclear Regulatory Commission (NRC) Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors" (GL 2004-02), for the North Anna Power Station Unit 2 and Unit 3 (North Anna 1 and North Anna 2). In its letter, Dominion stated that it has taken actions toward bringing North Anna 1 and North Anna 2 into compliance with GL 2004-02, including replacing the sump screens with substantially larger sump strainers during the fall 2007 refueling outage and the spring 2007 refueling outage, respectively. However, completion of the downstream effects evaluations and associated acceptance reviews for components, including the vessel and the fuel, have not been completed for the two units. In addition, chemical effects testing and evaluation, and associated acceptance reviews, have not been completed for the two units. Dominion also stated that determinations will have to be made as to whether any additional actions may be required based on the results of the foregoing technical evaluations and testing. Therefore, an extension to the compliance due date of December 31, 2007, was requested for North Anna 1 and North Anna 2 to allow time for completion of these activities.
As stated in SECY-06-0078, proposed extensions to permit changes at the next outage of opportunity after December 2007 may be granted based on the licensees request, if the staff determines that:
- 1. the licensee has a plant-specific technical/experimental plan with milestones and schedules to address outstanding technical issues with enough margin to account for uncertainties, and
- 2. 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.
Enclosure 3
In regard to the first criterion for approving an extension, Dominion has a plant-specific plan, with milestones and schedules, to complete the North Anna 1 and North Anna 2 GL 2004-02-required corrective actions and modifications by November 30, 2008. Specifically, Dominion plans to complete a revised downstream effects evaluations for components, including reactor vessel and fuel, by March 31, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by June 30, 2008. In addition Dominion plans to complete chemical effects evaluations and bench-top testing to determine likely precipitate formation and bounding quantities precipitates by March 31, 2008, complete reduced scale (head loss) testing to determine the effects of chemical precipitate formation, if required, by September 30, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by November 30, 2008.
In regard to the second criterion for approving an extension, Dominion has stated that various modifications, mitigating measures, compensatory measures, and/or favorable conditions are in effect at North Anna 1 and North Anna 2, minimizing the risk of degraded ECCS and CSS functions during the extension period, including large replacement sump strainers with a total of 6,400 sq. ft. surface area for North Anna 1 and a total of 6,300 sq. ft. surface area for North Anna 2.
Dominion also stated that for North Anna 2, it had either removed or replaced the Microtherm insulation within the containment, and for North Anna 1 and North Anna 2, it had either removed or replaced the calcium silicate insulation in the stream generator and pressurizer rooms.
Dominion further stated that it conducted various modifications to ensure strainer submergence.
In regard to the third criterion for approving an extension, Dominion has installed very large strainers in the containment sumps for both North Anna 1 and North Anna 2, and therefore, this criterion is considered to be met.
Dominion provided a risk evaluation for North Anna 1 and North Anna 2, which compared the increase in Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) from a large-break LOCA to total plant CDF and LERF risk values and showed that these values could be categorized as small in accordance with the criteria stated in Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis.
After reviewing Dominions submittal, the NRC staff concludes that Dominion has a plan to complete the remaining corrective actions and has compensatory measures in place. However, the plan is open-ended (based on the chemical effects hardware and/or procedural change decision point in November, 2008). Further, the NRC views the scope of the additional activities required to demonstrate compliance with GL 2004-02 as achievable by May 31, 2008.
The NRC has confidence that Dominions plan, as described in the November 15, 2007 letter, will result in the installation of final GSI-191 modifications that provide acceptable strainer function with adequate margin for uncertainties. Further, the NRC has concluded that Dominion has put mitigation measures in place to adequately reduce risk for an approximate 5-month extension period. However, the NRC finds that Dominion has an open-ended plan, and has not made a convincing case why the remaining North Anna 1 and North Anna 2 corrective actions for GL 2004-02 cannot be accomplished by May 2008. Given the importance of reaching a prompt closure of GL 2004-02, the NRC expects Dominion to complete GL 2004-02 corrective actions at North Anna 1 and North Anna 2 by May 31, 2008. Should Dominion not complete the North Anna 1 and North Anna 2 corrective actions for GL 2004-02 by May 31, 2008, Dominion will need to provide the NRC additional justification for the delay.
EXTENSION REQUEST FOR CONTAINMENT SUMP CORRECTIVE ACTIONS ASSOCIATED WITH GENERIC LETTER 2004-02 SURRY POWER STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-280 AND 50-281 In a letter dated November 15, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML073190553), Virginia Electric and Power Company (Dominion) requested an extension to the corrective action due date of December 31, 2007, stated in Nuclear Regulatory Commission (NRC) Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors" (GL 2004-02), for the Surry Power Station Unit 2 and Unit 3 (Surry 1 and Surry 2). In its letter, Dominion stated that it has taken actions toward bringing Surry 1 and Surry 2 into compliance with GL 2004-02, including replacing the sump screens with substantially larger sump strainers during the fall 2007 refueling outage and the fall 2006 refueling outage respectively. However, completion of the downstream effects evaluations and associated acceptance reviews for components, including the vessel and the fuel, have not been completed for the two units. In addition, chemical effects testing and evaluation, and associated acceptance reviews, have not been completed for the two units. Dominion also stated that determinations will have to be made as to whether any additional actions may be required based on the results of the foregoing technical evaluations and testing. Therefore, an extension to the compliance due date of December 31, 2007, was requested for Surry 1 and Surry 2 to allow time for completion of these activities.
As stated in SECY-06-0078, proposed extensions to permit changes at the next outage of opportunity after December 2007 may be granted based on the licensees request, if the staff determines that:
- 1. the licensee has a plant-specific technical/experimental plan with milestones and schedules to address outstanding technical issues with enough margin to account for uncertainties, and
- 2. 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.
Enclosure 4
In regard to the first criterion for approving an extension, Dominion has a plant-specific plan, with milestones and schedules, to complete the Surry 1 and Surry 2 GL 2004-02-required corrective actions and modifications by November 30, 2008. Specifically, Dominion plans to complete a revised downstream effects evaluations for components, including reactor vessel and fuel, by March 31, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by June 30, 2008. In addition, Dominion plans to complete chemical effects evaluations and bench-top testing to determine likely precipitate formation and bounding quantities precipitates by March 31, 2008, complete reduced scale (head loss) testing to determine the effects of chemical precipitate formation, if required, by September 30, 2008, and make a determination of, and schedule for, associated hardware and/or procedural modifications (if any) by November 30, 2008.
In regard to the second criterion for approving an extension, Dominion has stated that various modifications, mitigating measures, compensatory measures, and/or favorable conditions are in effect at Surry 1 and Surry 2, minimizing the risk of degraded ECCS and CSS functions during the extension period, including large replacement sump strainers with a total of 8,400 sq. ft. surface area for Surry 1 and a total of approximately 3,500 sq. ft. surface area for Surry 2 (the remaining approximate 5, 000 sq. ft. of strainer surface area is to be installed in the spring 2008 Surry 2 refueling outage under an NRC approved extension). Dominion also stated that for Surry 2 it had modified the Inside Recirculation Spray (IRS) pumps start signal to ensure strainer submergence.
Further, Dominion stated that for Surry 2 it had added a time delay to the Outside Recirculation Spray pumps start signal to reduce the load impact on the diesel generators and to allow sufficient time for the IRS pumps piping to fill and attain stable operation. Dominion stated that was installing the same modifications for Surry 1 during its fall 2007 refueling outage.
In regard to the third criterion for approving an extension, Dominion has installed very large strainers in the containment sumps for both Surry 1 and Surry 2, and therefore, this criterion is considered to be met.
Dominion provided a risk evaluation for Surry 1 and Surry 2 which compared the increase in Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) from a large-break LOCA to total plant CDF and LERF risk values and showed that these values could be categorized as small in accordance with the criteria stated in Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis.
After reviewing Dominions submittal, the NRC staff concludes that Dominion has a plan to complete the remaining corrective actions and has compensatory measures in place. However, the plan is open-ended (based on the chemical effects hardware and/or procedural change decision point in November, 2008). Further, the NRC views the scope of the additional activities required to demonstrate compliance with GL 2004-02 as achievable by May 31, 2008.
The NRC has confidence that Dominions plan, as described in the November 15, 2007 letter, will result in the installation of final GSI-191 modifications that provide acceptable strainer function with adequate margin for uncertainties. Further, the NRC has concluded that Dominion has put mitigation measures in place to adequately reduce risk for an approximate five-month extension period. However, the NRC finds that Dominion has an open-ended plan, and has not made a convincing case why the remaining Surry 1 and Surry 2 corrective actions for GL 2004-02 cannot
be accomplished by May 2008. Given the importance of reaching a prompt closure of GL 2004-02, the NRC expects Dominion to complete GL 2004-02 corrective actions at Surry 1 and Surry 2 by May 31, 2008. Should Dominion not complete the Surry 1 and Surry 2 corrective actions for GL 2004-02 by May 31, 2008, Dominion will need to provide the NRC additional justification for the delay.
Kewaunee Power Station, Millstone Power Station, Unit Nos. 2 and 3, North Anna Power Station, Unit Nos. 1 and 2, and Surry Power Station, Unit Nos. 1 & 2 cc:
Mr. David A. Christian Office of the Attorney General President and Chief Nuclear Officer Commonwealth of Virginia Virginia Electrical and Power Company 900 East Main Street Innsbrook Technical Center Richmond, Virginia 23219 5000 Dominion Boulevard Glen Allen, VA 23060-6711 Mr. Chris L. Funderburk, Director Nuclear Licensing & Operations Support Ms. Lillian M. Cuoco, Esq. Dominion Resources Services, Inc.
Senior Counsel Innsbrook Technical Center Dominion Resources Services, Inc. 5000 Dominion Blvd.
Building 475, 5th Floor Glen Allen, Virginia 23060-6711 Rope Ferry Road Waterford, Connecticut 06385 Mr. C. Lee Lintecum County Administrator Mr. Donald E. Jernigan Louisa County Site Vice President Post Office Box 160 Surry Power Station Louisa, Virginia 23093 Virginia Electric and Power Company 5570 Hog Island Road Old Dominion Electric Cooperative Surry, Virginia 23883-0315 4201 Dominion Blvd.
Glen Allen, Virginia 23060 Senior Resident Inspector Surry Power Station Senior Resident Inspector U. S. Nuclear Regulatory Commission North Anna Power Station 5850 Hog Island Road U. S. Nuclear Regulatory Commission Surry, Virginia 23883 P. O. Box 490 Mineral, Virginia 23117 Chairman Board of Supervisors of Surry County Mr. Daniel G. Stoddard Surry County Courthouse Site Vice President Surry, Virginia 23683 North Anna Power Station Virginia Electric and Power Company Dr. W. T. Lough Post Office Box 402 Virginia State Corporation Commission Mineral, Virginia 23117-0402 Division of Energy Regulation Post Office Box 1197 Mr. William R. Matthews Richmond, Virginia 23218 Senior Vice President, Nuclear Operations Virginia Electrical and Power Company Dr. Robert B. Stroube, MD, MPH Innsbrook Technical Center State Health Commissioner 5000 Dominion Boulevard Office of the Commissioner Glen Allen, VA 23060-6711 Virginia Department of Health Post Office Box 2448 Richmond, Virginia 23218
Kewaunee Power Station, Millstone Power Station, Unit Nos. 2 and 3, North Anna Power Station, Unit Nos. 1 and 2, and Surry Power Station, Unit Nos. 1 & 2 cc:
Edward L. Wilds, Jr., Ph.D. Mr. Joseph Roy Director, Division of Radiation Director of Operations Department of Environmental Massachusetts Municipal Wholesale Protection Electric Company 79 Elm Street P.O. Box 426 Hartford, CT 06106-5127 Ludlow, MA 01056 Regional Administrator, Region I Mr. William D. Bartron U.S. Nuclear Regulatory Commission Licensing Supervisor 475 Allendale Road Dominion Nuclear Connecticut, Inc.
King of Prussia, PA 19406 Building 475, 5th Floor Roper Ferry Road First Selectmen Waterford, CT 06385 Town of Waterford 15 Rope Ferry Road Mr. J. Alan Price Waterford, CT 06385 Site Vice President Dominion Nuclear Connecticut, Inc.
Charles Brinkman, Director Building 475, 5th Floor Washington Operations Nuclear Services Rope Ferry Road Westinghouse Electric Company Waterford, CT 06385 12300 Twinbrook Pkwy, Suite 330 Rockville, MD 20852 Ms. Leslie N. Hartz Dominion Energy Kewaunee, Inc.
Senior Resident Inspector Kewaunee Power Station Millstone Power Station N 490 Highway 42 c/o U.S. Nuclear Regulatory Commission Kewaunee, WI 54216 P. O. Box 513 Niantic, CT 06357 Resident Inspectors Office U. S. Nuclear Regulatory Commission Mr. J. W. "Bill" Sheehan N490 Highway 42 Co-Chair NEAC Kewaunee, WI 54216-9510 19 Laurel Crest Drive Waterford, CT 06385 Mr. Thomas L. Breene Dominion Energy Kewaunee, Inc.
Ms. Nancy Burton Kewaunee Power Station 147 Cross Highway N490 Highway 42 Redding Ridge, CT 00870 Kewaunee, WI 54216 Mr. Evan W. Woollacott Co-Chair Nuclear Energy Advisory Council 128 Terrys Plain Road Simsbury, CT 06070