L-MT-11-044, Uprate (Epu): Update on EPU Commitments

Uprate (Epu): Update on EPU Commitments

ML11249A045
Person / Time
Site:	Monticello
Issue date:	08/30/2011
From:	O'Connor T Xcel Energy, Northern States Power Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-MT-11-044, TAC MD9990
Download: ML11249A045 (15)

Text

&XcelEnergy@ Monticello Nuclear Generating Plant 2807 W County Rd 75 Monticello, MN 55362 August 30, 2011 L-MT-1 1-044 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC' 20555-0001 Monticello Nuclear Generating Plant Docket 50-263 Renewed License No. DPR-22

Subject:

Monticello Extended Power Uprate (EPU): Update on EPU Commitments (TAC MD9990)

References:

1) Letter from Northern States Power Company, a Minnesota corporation (NSPM), d/b/a Xcel Energy to Document Control Desk, "License Amendment Request: Extended Power Uprate (TAC MD9990)," L-MT-08-052, dated November 5, 2008. (ADAMS Accession No. ML083230111)

2) Letter from T. J. O'Connor (NSPM), to Document Control Desk (NRC),

"Monticello Extended Power Uprate: Updates to Docketed Information (TAC MD9990)," L-MT-10-072, dated December 21, 2010. (ADAMS Accession No. ML103570026)

Pursuant to 10 CFR 50.90, the Northern States Power Company, a Minnesota corporation (NSPM), doing business as Xcel Energy, requested in Reference 1 an amendment to the Monticello Nuclear Generating Plant (MNGP) Renewed Operating License (OL) and Technical Specifications (TS) to increase the maximum authorized power level from 1775 megawatts thermal (MWt) to 2004 MWt.

The purpose of this letter is to provide the NRC with the status of analyses and commitments previously provided to the NRC for the MNGP extended power uprate (EPU). Updates are provided in the following enclosures:

Enclosure 1 - Feedwater/Condensate Events and Feedwater/Condensate Pump Area Heat Load Enclosure 2 - Modification of Pipe Support TWH-143 Enclosure 3 - Appendix R Modifications to Vent and Purge Valves Enclosure 4 - Summary of Extended Power Uprate Commitments 00

Document Control Desk Page 2 The changes made in herein do not revise the no significant hazards consideration (NSHC) provided in Reference 2.

In accordance with 10 CFR 50.91(b), a copy of this application supplement, without enclosures, is being provided to the designated Minnesota Official.

Summary of Commitments This letter makes no new commitments. This letter closes commitments and revises commitments associated with the EPU project. See Enclosure 4 for details. The commitment summary includes whether the commitment is new, revised, or completed.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on: August 30, 2011

-T,15-0 Timothy J. O'Connor

^ Site Vice-President Monticello Nuclear Generating Plant Northern States Power Company-Minnesota Enclosures (4) cc: Administrator, Region III, USNRC (w/o enclosures)

Resident Inspector, Monticello Nuclear Generating Plant, USNRC (w/o enclosures)

Project Manager, Monticello Nuclear Generating Plant, USNRC Minnesota Department of Commerce (w/o enclosures)

L-MT-1 1-044 ENCLOSURE 1 FEEDWATER/CONDENSATE EVENTS AND FEEDWATER/CONDENSATE PUMP AREA HEAT LOAD 2 pages follow

L-MT-1 1-044 FEEDWATER/CONDENSATE EVENTS AND FEEDWATER/CONDENSATE PUMP AREA HEAT LOAD

Background

In Reference E1-1, Northern States Power Company, a Minnesota corporation (NSPM),

d/b/a Xcel Energy provided a license amendment request (LAR) for the Monticello Nuclear Generating Plant. The Reference E1-1 LAR requested approval to increase the maximum authorized power level from 1775 megawatts thermal (MWt) to 2004 MWt.

In Reference E1-2, NSPM provided a response to NRC requests for additional information (RAIs). As part of the response to RAI 2.12.2, NSPM made the following commitment:

NSPM will perform an analysis prior to RF025 to predict combined Condensate and Feedwatersystem performance for normal operation and for transientsincluding Single Feedwaterpump trip, FeedwaterControl System Failureand Single Condensate Pump Trip. Acceptance criteria will include adequate margin to preclude loss of both reactorfeedwaterpumps from low suction pressure or flow.

In Reference E1-3, NSPM provided a response to NRC RAIs. As part of the response to RAI 35, NSPM made the following commitment:

NSPM commits to evaluating the changes in condensate and feed pump area heat load to confirm temperaturesremain within design limits prior to RF025. If necessary,modifications to the HVAC system for this area will be implemented to maintain these areas within the design limits.

Both of these commitments have not been met as MNGP entered refueling outage 25 (RF025) on March 5, 2011 and the subject analyses and evaluations have not been completed.

Discussion Both commitments require calculations and analyses to complete the commitment requirements. Depending on the outcome of the evaluations further modifications may also be required.

Each commitment has been reviewed for change by the Regulatory Commitment Change process. The results of this review indicated that both commitments may be changed without prior consent of the NRC. NSPM has determined that both commitments are not required to be implemented until MNGP ascends to Extended Power Uprate (EPU) conditions. Since EPU is not yet approved for MNGP, there is no safety concern with modifying the due date for these commitments.

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L-MT-1 1-044 Conclusion Based on the above, NSPM is modifying the commitments to change the commitment due date from "prior to RF025" to "prior to EPU implementation." No change of substance of the commitment is proposed only the schedule for completion is changed.

Based on this change each commitment will read as follows:

NSPM will perform an analysisprior to EPU implementation to predict combined Condensate and Feedwatersystem performance for normal operationand for transients including Single Feedwaterpump trip, Feedwater Control System Failure and Single Condensate Pump Trip. Acceptance criteria will include adequate margin to preclude loss of both reactorfeedwaterpumps from low suction pressure or flow.

NSPM commits to evaluating the changes in condensate and feed pump area heat load to confirm temperaturesremain within design limits prior to EPU implementation. If necessary, modifications to the HVAC system for this area will be implemented to maintain these areas within the design limits.

References:

El-1 Letter from Northern States Power Company, a Minnesota corporation (NSPM),

d/b/a Xcel Energy to Document Control Desk, "License Amendment Request:

Extended Power Uprate (TAC MD9990)," L-MT-08-052, dated November 5, 2008. (ADAMS Accession No. ML083230111)

E1-2 Letter from T. J. O'Connor (NSPM), to Document Control Desk (NRC),

"Monticello Extended Power Uprate: Response to NRC Balance of Plant Review Branch (SBPB) Request for Additional Information (RAI) dated March 23, 2009 (TAC No. MD9990)," L-MT-09-046, dated June 12, 2009. (ADAMS Accession No. ML091670410)

E1-3 Letter from T. J. O'Connor (NSPM), to Document Control Desk (NRC),

"Monticello Extended Power Uprate: Response to NRC Containment and Ventilation Review Branch (SCVB) Request for Additional Information (RAI) dated March 19, 2009, and March 26, 2009 (TAC No. MD9990)," L-MT-09-048, dated July 13, 2009. (ADAMS Accession No. ML092170404)

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L-MT-1 1-044 ENCLOSURE 2 MODIFICATION OF PIPE SUPPORT TWH-143 I page follows

L-MT-1 1-044 MODIFICATION OF PIPE SUPPORT TWH-143

Background

In Reference E2-1, Northern States Power Company, a Minnesota corporation (NSPM),

d/b/a Xcel Energy provided a license amendment request (LAR) for the Monticello Nuclear Generating Plant. The Reference E2-1 LAR requested to increase the maximum authorized power level from 1775 megawatts thermal (MWt) to 2004 MWt.

In Reference E2-2, NSPM provided a response to NRC requests for additional information (RAIs). As part of the response to RAI 12(b), NSPM made the following commitment:

Confirmation that modification of support TWH- 143 is complete will be provided to the NRC priorto implementation of the EPU license amendment request.

This commitment has been completed as indicated below.

Discussion As indicated in reference E2-2, NSPM performed a series of calculations and analyses to determine the acceptability of stresses in piping systems, i.e. the piping system meets code requirements. As a result of the analyses for Torus attached piping, support TWH-143 was identified as requiring modification to meet acceptable stress levels. Based on this NSPM developed and implemented a modification to replace TWH-143 with an adequate support.

The modification to TWH-143 was recently installed and post-maintenance tested satisfactorily.

Conclusion Based on the above, NSPM completed the commitment described above and is hereby notifying the NRC that the modification has been completed. Therefore, this commitment has been satisfied and is considered closed, with no further action required.

References:

E2-1 Letter from Northern States Power Company, a Minnesota corporation (NSPM),

d/b/a Xcel Energy to Document Control Desk, "License Amendment Request:

Extended Power Uprate (TAC MD9990)," L-MT-08-052, dated November 5, 2008. (ADAMS Accession No. ML083230111)

E2-2 Letter from T. J. O'Connor (NSPM), to Document Control Desk (NRC),

"Response to NRC Mechanical and Civil Engineering Review Branch (EMCB)

Requests for Additional Information (RAIs) dated March 28, 2009 (TAC MD9990)," L-MT-09-044, dated August 21, 2009. (ADAMS Accession No. ML092390332)

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L-MT-1 1-044 ENCLOSURE 3 APPENDIX R MODIFICATIONS TO VENT AND PURGE VALVES 2 Pages follow

L-MT-1 1-044 APPENDIX R MODIFICATIONS TO VENT AND PURGE VALVES

Background

In Reference E3-1 Northern States Power Company, a Minnesota corporation (NSPM),

d/b/a Xcel Energy provided a license amendment request (LAR) for the Monticello Nuclear Generating Plant. The Reference E3-1 LAR requested to increase the maximum authorized power level from 1775 megawatts thermal (MWt) to 2004 MWt.

In Reference E3-2, NSPM provided Licensee Event Report (LER) 2009-001, Revision 2.

In this LER NSPM identified that depending on initial conditions, a fire in the cable spreading room or control room, with or without a fire induced loss of off site power, could cause two in-series valves (containment purge and vent valves) to spuriously open leading to venting of containment. For certain design basis accident scenarios and 10 CFR 50 Appendix R events under Extended Power Uprate (EPU) conditions, containment accident pressure is required in order to ensure adequate net positive suction head (NPSH) is available for vessel injection and suppression pool cooling pumps. Venting of containment during this scenario could result in the loss of required NPSH for the #12 Core Spray (CS) and the #12 Residual Heat Removal (RHR) pumps.

With no operator action, inadequate NPSH could prevent vessel injection and/or suppression pool cooling. The station procedure for performing a shutdown from outside the control room did not contain any steps to require operators to ensure adequate NPSH was maintained.

Discussion As indicated in reference E3-2, to correct the condition NSPM would either evaluate the non-compliant manual actions as acceptable or correct the non-compliant manual actions via physical changes to the plant. Based on this, NSPM developed and implemented a modification to reroute the cabling associated with the purge and vent valves to eliminate the potential spurious opening of both valves from a single event.

The modification to the purge and vent valve cables was installed and post-maintenance tested satisfactorily during refueling outage 25 (RF025).

Conclusion Based on the above, NSPM completed the corrective action and is hereby notifying the NRC that the modification has been completed. No further impacts regarding the availability of containment accident pressure have been identified. Therefore, this condition has been satisfied and is considered closed, with no further action required.

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L-MT-1 1-044

References:

E3-1 Letter from Northern States Power Company, a Minnesota corporation (NSPM),

d/b/a Xcel Energy to Document Control Desk, "License Amendment Request:

Extended Power Uprate (TAC MD9990)," L-MT-08-052, dated November 5, 2008. (ADAMS Accession No. ML083230111)

E3-2 Letter from T. J. O'Connor (NSPM), to Document Control Desk (NRC), "LER 2009-001, Revision 2, "Containment Overpressure Not Ensured in the Appendix R Analysis," L-MT-10-070, dated December 22, 2010. (ADAMS Accession No. MLI103570034)

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L-MT-1 1-044 ENCLOSURE 4

SUMMARY

OF EXTENDED POWER UPRATE COMMITMENTS 4 Pages follow

L-MT-1 1-044 Summary of Extended Power Uprate Commitments Below is the complete list of NRC commitments for the Extended Power Uprate (EPU) project prior to issuance of this letter.

No. Letter No. Date Commitment text Status 1 L-MT-08-052 NSPM will inspect the steam dryer during Complete -

11/5/2008 the next refueling outage to confirm no performed in unexpected changes in crack length on the RF024.

steam dryer. (L-MT-10-046) 2 L-MT-09-017 The steady state bypass void fraction for the Complete -

3/19/2009 EPU core will be calculated using the provided in method described by the NSPM response to Cycle 25 NRC RAI SNPB-7 of L-MT-09-017. Supplemental Reload Licensing Report (SRLR).

(L-MT-10-046) 3 L-MT-09-043 NSPM will provide the evaluation of steam Deleted -

8/12/2009 dryer structural integrity to the NRC staff Commitment no prior to further increases in reactor power longer required.

when increasing to power levels above (L-MT-10-046)

CLTP.

4 L-MT-09-043 NSPM will perform outage steam dryer Active 8/12/2009 inspections based on the guidance of BWRVIP [Boiling Water Reactor Vessel Internals Project].

5 L-MT-09-044 Confirmation that Feedwater and Active 8/21/2009 Condensate pump and heater replacement modifications are complete and meet the code allowables will be provided to the NRC prior to implementation of the EPU license amendment request.

6 L-MT-09-044 Confirmation that modification of support Active 8/21/2009 TWH-143 is complete will be provided to the NRC prior to implementation of the EPU license amendment request.

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L-MT-1 1-044 7 L-MT-09-046 NSPM will perform an analysis prior to Active 6/12/2009 RF025 to predict combined Condensate and Feedwater system performance for normal operation and for transients including Single Feedwater pump trip, Feedwater Control System Failure and Single Condensate Pump Trip. Acceptance criteria will include adequate margin to preclude loss of both reactor feedwater pumps from low suction pressure or flow.

8 L-MT-10-072 Prior to implementation of EPU, the USAR Active 12/21/2010 will be revised to indicate that the Revised from emergency heat load of 24.7 MBTU/hr original in L-MT- occurs approximately 192 hours0.00222 days <br />0.0533 hours <br />3.174603e-4 weeks <br />7.3056e-5 months <br /> after 09-046 6/12/2009 shutdown.

9 L-MT-09-048 NSPM commits to evaluating the changes in Active 7/13/2009 condensate and feed pump area heat load to confirm temperatures remain within design limits prior to RF025. If necessary, modifications to the HVAC system for this area will be implemented to maintain these areas within the design limits.

10 L-MT-09-100 If NRR agrees to review the MELLLA+ Complete -

10/28/2009 [Maximum Extended Load Line Limit NRC Analysis Plus] LAR concurrent with the EPU acceptance of LAR, NSPM will commit in the MELLLA+ MELLLA+ LAR.

LAR to resolve the CAP section in the same (L-MT-10-046) manner as the issue is resolved for the delayed EPU amendment.

11 L-MT-10-046 As part of MNGP restart following Active 6/30/2010 installation of the replacement steam dryer, NSPM will implement the Power Ascension Test Plan found in Enclosure 1, Appendix 5 of L-MT-10-046.

Revised or Completed Commitments Commitment 6 is completed as described in Enclosure 2 Commitment 7 is revised as described in Enclosure 1 Commitment 9 is revised as described in Enclosure 1 Final List of EPU Commitments Based on these changes and the revised commitments associated with this letter the revised EPU commitments table is as follows:

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L-MT-1 1-044 Extended Power Uprate Commitments No. Letter No. Date Commitment text Status 1 L-MT-08-052 NSPM will inspect the steam dryer during the Complete 11/5/2008 next refueling outage to confirm no (L-MT-10-046) unexpected changes in crack length on the steam dryer.

2 L-MT-09-017 The steady state bypass void fraction for the Complete 3/19/2009 EPU core will be calculated using the method (L-MT-10-046) described by the NSPM response to NRC RAI SNPB-7 of L-MT-09-017.

3 L-MT-09-043 NSPM will provide the evaluation of steam Deleted 8/12/2009 dryer structural integrity to the NRC staff (L-MT-10-046) prior to further increases in reactor power when increasing to power levels above CLTP.

4 L-MT-09-043 NSPM will perform outage steam dryer Active 8/12/2009 inspections based on the guidance of BWRVIP.

5 L-MT-09-044 Confirmation that Feedwater and Active 8/21/2009 Condensate pump and heater replacement modifications are complete and meet the code allowables will be provided to the NRC prior to implementation of the EPU license amendment request.

6 L-MT-09-044 Confirmation that modification of support Complete 8/21/2009 TWH-143 is complete will be provided to the (L-MT-1 1-044)

NRC prior to implementation of the EPU license amendment request.

7 L-MT-11-044 NSPM will perform an analysis prior to EPU Active Enclosure 1 implementation to predict combined Revised from Condensate and Feedwater system original in L-MT- performance for normal operation and for 09-046 transients including Single Feedwater pump 6/12/2009 trip, Feedwater Control System Failure and Single Condensate Pump Trip. Acceptance criteria will include adequate margin to preclude loss of both reactor feedwater pumps from low suction pressure or flow.

8 L-MT-10-072 Prior to implementation of EPU, the USAR Active 12/21/2010 will be revised to indicate that the emergency Revised from heat load of 24.7 MBTU/hr occurs original in L-MT- approximately 192 hours0.00222 days <br />0.0533 hours <br />3.174603e-4 weeks <br />7.3056e-5 months <br /> after shutdown..09-046 6/12/2009 Page 3 of 4

L-MT-1 1-044 9 L-MT-1 1-044 NSPM commits to evaluating the changes in Active Enclosure 1 condensate and feed pump area heat load to Revised from confirm temperatures remain within design original in L-MT- limits prior to EPU implementation. If 09-048 necessary, modifications to the HVAC 7/13/2009 system for this area will be implemented to maintain these areas within the design limits.

10 L-MT-09-100 If NRR agrees to review the MELLLA+ LAR Complete 10/28/2009 concurrent with the EPU LAR, NSPM will (L-MT-10-046) commit in the MELLLA+ LAR to resolve the CAP section in the same manner as the issue is resolved for the delayed EPU amendment.

11 L-MT-10-046 As part of MNGP restart following installation Active 6/30/2010 of the replacement steam dryer, NSPM will implement the Power Ascension Test Plan found in Enclosure 1, Appendix 5 of L-MT-10-046.

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