NRC 2009-0113, Generic Letter 2004-02, Potential Impact for Debris Blockage in Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors (TAC Nos. MC4705/4706)
| ML093000354 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 10/27/2009 |
| From: | Meyer L Point Beach |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-04-002, NRC 2009-0113, TAC MC4705, TAC MC4706 | |
| Download: ML093000354 (3) | |
Text
October 27,2009 NRC 2009-01 13 GL 2004-02 U. S. Nuclear Regulatory Commission AlTN: Document Control Desk Washington, DC 20555 Point Beach Nuclear Plant, Units 1 and 2 Dockets 50-266 and 50-301 Renewed License Nos. DPR-24 and DPR-27 Generic Letter 2004-02 Potential Impact for Debris Blockage in Emeraencv Recirculation During Design Basis Accidents at Pressurized-Water Reactors (TAC Nos. MC470514706)
References (1) NextEra Energy Point Beach, LLC, Letter to NRC, dated June 12,2009, Request for Extension of Unit 1 and 2 Completion Dates for Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors (TAC Nos. MC4719 and MC4720)
(2) NRC Letter to NextEra Energy Point Beach Nuclear Plant Units 1 and 2, dated June 30, 2009, GSI-19IIGL 2004-02, Additional Extension Request Approval (TAC Nos. MC4705 and MC4706) (ML091800430)
The purpose of this letter is to inform the NRC staff that there has been a change to the plan associated with the Unit 2 Phase 1 fiber reduction activities that are being implemented during the current Unit 2 refueling outage. The scope of the Phase 1 activities was previously described in Section 3.1 of the enclosure for Reference (1). The change to the plan was discussed with the NRC Point Beach Project Manager on October 23, 2009. This change is driven primarily by the determination of the actual dose rates in the work areas, the work complexity, and NextEra's focus on performing this work through a more dose effective execution plan.
The plan change does not alter the Regulatory Commitments specified in Reference ( I ) as confirmed by the Commission's evaluation contained in Reference (2) which stated:
"NextEra will complete modifications to resolve GSI-191 at Point Beach Nuclear Plant (PBNP) by June 30,2010, for Unit 1, and by June 30,201 I, for PBNP Unit 2."
NextEra Energy Point Beach, LLC, 6610 Nuclear Road, Two Rivers, WI 54241
Document Control Desk Page 2 Specifically, NextEra Energy Point Beach, LLC (NextEra) intends to defer fibrous insulation replacement activities associated with the reactor coolant pump (RCP) bowls and the steam generator upper shells (i.e., if the 5D Zone of lnfluence (ZOI) issues are not resolved) until the spring 2011 refueling outage for Unit 2.
The RCP bowl and steam generator upper shell (i.e., if the 5D Zone of lnfluence (ZOI) issues are not resolved) fiber reduction activities are being deferred to the Spring 2011 outage because the craft hours used for dose estimates have proven to be significantly underestimated due to job complexity. There was no opportunity for previous outage planning as this work scope evolved through industry learnings. Additionally, there was a lack of available dose rate information for ALARA planning for areas inside the steam generator cubicles and around the RCP bowls where work is not normally performed.
Based upon data obtained during the current Unit 2 refueling outage, NextEra estimates that approximately 50 Rem personnel exposure will be received rather than the 9.5 Rem previously planned for. NextEra estimates that completing the revised Phase 1 scope of work (i.e.,
replacement of approximately 505 ft3of insulation versus the plan to replace 685 ft3of insulation as discussed below) during the current Unit 2 refueling outage will result in significantly less personnel exposure.
The revised Phase 1 scope of work to be completed during the current Unit 2 refueling outage includes replacement of the insulation on the steam generator channel heads and the reactor coolant system loops as necessary to ensure no NUKONO insulation on these components remains within the ZOI. This will result in replacement of approximately 505 ft3 of insulation rather than the approximately 685 ft3of insulation previously stated in Reference (1). The modifications to install three additional strainer modules on each train of strainers and structurally reinforce the strainer assemblies to accommodate an increased differential pressure will also be completed during the current Unit 2 refueling outage.
Detailed walkdowns described in Reference ( I ) are being performed during the current Unit 2 refueling outage in preparation for insulation replacement during the spring 2011 Unit 2 refueling outage. These walkdowns will include obtaining necessary dose rate data to ensure insulation replacement during the Unit 2 Spring 2011 refueling outage is maintained ALARA with substantially reduced doses for the project expected.
Installing shielding packages, aggressive cleanup of the reactor coolant system and improved work planning will be incorporated into the insulation removal and installation activities during the spring 2011 Unit 2 refueling outage. Based upon data gathered during the current Unit 2 refueling outage, NextEra estimates that these activities will result in a reduction in dose of approximately 50%. The lessons learned from the current Unit 2 refueling outage will be applied to similar work activities during the Unit 1 Spring 2010 refueling outage.
The fiber reduction activities and strainer module modifications being implemented during the current Unit 2 refueling outage continue to ensure a high level of emergency core cooling system (ECCS) pump performance.
Document Control Desk Page 3 If you have questions or require additional information, please contact Mr. James Costedio at 9201755-7427.
A copy of this submittal has been provided to the designated Wisconsin Official.
Very truly yours, NextEra Energy Point Beach, LLC cc: Resident Inspector, Point Beach Nuclear Plant, USNRC Project Manager, Point Beach Nuclear Plant, USNRC Administrator, Region Ill, USNRC PSCW
Text
October 27,2009 NRC 2009-01 13 GL 2004-02 U. S. Nuclear Regulatory Commission AlTN: Document Control Desk Washington, DC 20555 Point Beach Nuclear Plant, Units 1 and 2 Dockets 50-266 and 50-301 Renewed License Nos. DPR-24 and DPR-27 Generic Letter 2004-02 Potential Impact for Debris Blockage in Emeraencv Recirculation During Design Basis Accidents at Pressurized-Water Reactors (TAC Nos. MC470514706)
References (1) NextEra Energy Point Beach, LLC, Letter to NRC, dated June 12,2009, Request for Extension of Unit 1 and 2 Completion Dates for Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors (TAC Nos. MC4719 and MC4720)
(2) NRC Letter to NextEra Energy Point Beach Nuclear Plant Units 1 and 2, dated June 30, 2009, GSI-19IIGL 2004-02, Additional Extension Request Approval (TAC Nos. MC4705 and MC4706) (ML091800430)
The purpose of this letter is to inform the NRC staff that there has been a change to the plan associated with the Unit 2 Phase 1 fiber reduction activities that are being implemented during the current Unit 2 refueling outage. The scope of the Phase 1 activities was previously described in Section 3.1 of the enclosure for Reference (1). The change to the plan was discussed with the NRC Point Beach Project Manager on October 23, 2009. This change is driven primarily by the determination of the actual dose rates in the work areas, the work complexity, and NextEra's focus on performing this work through a more dose effective execution plan.
The plan change does not alter the Regulatory Commitments specified in Reference ( I ) as confirmed by the Commission's evaluation contained in Reference (2) which stated:
"NextEra will complete modifications to resolve GSI-191 at Point Beach Nuclear Plant (PBNP) by June 30,2010, for Unit 1, and by June 30,201 I, for PBNP Unit 2."
NextEra Energy Point Beach, LLC, 6610 Nuclear Road, Two Rivers, WI 54241
Document Control Desk Page 2 Specifically, NextEra Energy Point Beach, LLC (NextEra) intends to defer fibrous insulation replacement activities associated with the reactor coolant pump (RCP) bowls and the steam generator upper shells (i.e., if the 5D Zone of lnfluence (ZOI) issues are not resolved) until the spring 2011 refueling outage for Unit 2.
The RCP bowl and steam generator upper shell (i.e., if the 5D Zone of lnfluence (ZOI) issues are not resolved) fiber reduction activities are being deferred to the Spring 2011 outage because the craft hours used for dose estimates have proven to be significantly underestimated due to job complexity. There was no opportunity for previous outage planning as this work scope evolved through industry learnings. Additionally, there was a lack of available dose rate information for ALARA planning for areas inside the steam generator cubicles and around the RCP bowls where work is not normally performed.
Based upon data obtained during the current Unit 2 refueling outage, NextEra estimates that approximately 50 Rem personnel exposure will be received rather than the 9.5 Rem previously planned for. NextEra estimates that completing the revised Phase 1 scope of work (i.e.,
replacement of approximately 505 ft3of insulation versus the plan to replace 685 ft3of insulation as discussed below) during the current Unit 2 refueling outage will result in significantly less personnel exposure.
The revised Phase 1 scope of work to be completed during the current Unit 2 refueling outage includes replacement of the insulation on the steam generator channel heads and the reactor coolant system loops as necessary to ensure no NUKONO insulation on these components remains within the ZOI. This will result in replacement of approximately 505 ft3 of insulation rather than the approximately 685 ft3of insulation previously stated in Reference (1). The modifications to install three additional strainer modules on each train of strainers and structurally reinforce the strainer assemblies to accommodate an increased differential pressure will also be completed during the current Unit 2 refueling outage.
Detailed walkdowns described in Reference ( I ) are being performed during the current Unit 2 refueling outage in preparation for insulation replacement during the spring 2011 Unit 2 refueling outage. These walkdowns will include obtaining necessary dose rate data to ensure insulation replacement during the Unit 2 Spring 2011 refueling outage is maintained ALARA with substantially reduced doses for the project expected.
Installing shielding packages, aggressive cleanup of the reactor coolant system and improved work planning will be incorporated into the insulation removal and installation activities during the spring 2011 Unit 2 refueling outage. Based upon data gathered during the current Unit 2 refueling outage, NextEra estimates that these activities will result in a reduction in dose of approximately 50%. The lessons learned from the current Unit 2 refueling outage will be applied to similar work activities during the Unit 1 Spring 2010 refueling outage.
The fiber reduction activities and strainer module modifications being implemented during the current Unit 2 refueling outage continue to ensure a high level of emergency core cooling system (ECCS) pump performance.
Document Control Desk Page 3 If you have questions or require additional information, please contact Mr. James Costedio at 9201755-7427.
A copy of this submittal has been provided to the designated Wisconsin Official.
Very truly yours, NextEra Energy Point Beach, LLC cc: Resident Inspector, Point Beach Nuclear Plant, USNRC Project Manager, Point Beach Nuclear Plant, USNRC Administrator, Region Ill, USNRC PSCW