L-PI-12-082, Response to Requests for Additional Information (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology

Response to Requests for Additional Information (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodology

ML12258A057
Person / Time
Site:	Prairie Island
Issue date:	09/13/2012
From:	Molden J Northern States Power Co, Xcel Energy
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
L-PI-12-082, TAC ME2609, TAC ME2610
Download: ML12258A057 (8)

Text

@ Xcel Energy8 L-PI-12-082 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Units 1 and 2 Dockets 50-282 and 50-306 Renewed License Nos. DPR-42 and DPR-60 Response to Requests for Additional Information (RAI) Associated with Adoption of the Alternative Source Term (AST) Methodoloav (TAC Nos. ME2609 and ME2610)

In a letter to the U.S. Nuclear Regulatory Commission (NRC) dated October 27, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML093160605), the Northern States Power Company, a Minnesota corporation doing business as Xcel Energy (hereafter "NSPM"), requested an amendment to the Technical Specifications (TS) for Prairie Island Nuclear Generating Plant (PINGP). The proposed amendment requested adoption of the Alternative Source Term (AST) methodology, in addition to TS changes supported by AST design basis accident radiological consequence analyses.

In a letter dated February 24, 2012 (ADAMS Accession No. ML12058A069), NSPM notified NRC of a potential ventilation flow path diversion that could challenge an assumption in the radiological release analysis of several plant accidents. Therefore, that letter included a commitment to eliminate the 121 Laundry Fan exhaust path as a potential source of post-accident radioactive release following an accident. To complete their review of this issue, the NRC staff requested additional information by electronic mail dated August 13, 2012. to this letter provides a proposed License Condition that will supersede the related commitment (Commitment No. I ) made in the February 24, 2012 letter. Note that the License Condition proposed herein is shown as a markup to Appendix B of the Renewed Operating License as proposed in NSPM letter dated June 22,201 1 (ADAMS Accession No. M L I 11740145). That June 22, 201 1 letter had proposed two License Conditions associated with AST license amendment implementation. NSPM will implement the License Condition within the terms stated in the proposed License Condition.

The proposed license condition uses terminology different from that in the original commitment, while maintaining the original intent (i.e., preclude the 121 Laundry Fan exhaust leakage path). These changes were made to recognize the gravity of the license condition, while offering the flexibility needed as the project progresses into the 1717 Wakonade Drive East Welch, Minnesota 55089-9642 Telephone: 651.388.1 121

Document Control Desk Page 2 design phase. A quality design should not preclude any design or operational approach that best serves the design objective. Two such approaches are discussed below and may be considered for the design:

A purely physical plant modification might involve instruments and controls to automatically isolate the laundry fan and damper for the events that require the isolation. Such a modification could be extensive.

Another physical plant modification might involve disconnecting electrical power to the laundry fan and isolating control air to the damper to ensure that the flowpath is normally isolated. This design (with associated procedural controls) would allow for re-energizing the air and damper under administrative controls if radiological conditions required venting the Monitor Tanks to the Auxiliary Building Normal Ventilation Stack. By necessity, the review of these administrative controls would address the potential for leakage through this flowpath for any accident that might occur during the venting operation.

Any design or procedural modification would be approved under our 10 CFR 50 Appendix B QA Program and our 10 CFR 50.59 Review Program, and would have to meet the proposed License Condition.

NSPM submits this supplement in accordance with the provisions of 10 CFR 50.90.

The supplemental information provided in this letter does not impact the conclusions of the Determination of No Significant Hazards Consideration and Environmental Assessment presented in the October 27, 2009 submittal, supplemented by letters dated April 29,2010 (ADAMS Accession No. ML101200083), May 25,2010 (ADAMS Accession No. ML101460064), June 23,2010 (ADAMS Accession No. ML101760017),

August 12,2010 (ADAMS Accession No. ML102300295), December 17,2010 (ADAMS Accession No. ML103510322), June 22,201 1 (ADAMS Accession No. MLI 11740145),

July 11,2011 (ADAMS Accession No. MLI 11930157), August 9, 201 1 (ADAMS Accession No. MLI 12220098), December 8,201 1 (ADAMS Accession No. MLI 13430091), February 13,2012 (ADAMS Accession No. ML120460484), and February 24,2012 (ADAMS Accession No. ML12058A069).

In accordance with 10 CFR 50.91, NSPM is notifying the State of Minnesota of this License Amendment Request (LAR) supplement by transmitting a copy of this letter to the designated State Official.

If there are any questions or if additional information is needed, please contact Glenn Adams at (612) 330-6777.

Document Control Desk Page 3 Summarv of Commitments The license conditions of this letter supersede the following commitment made in NSPM letter dated February 24, 2012 (ADAMS Accession No. MLI2058A069):

Commitment Due Date

1. Implement a plant modification that will either block Within 90 days after the 121 ~aundryFan exhaust flow path permanently or completion of the outage in will otherwise remove the 121 Laundry Fan exhaust which the Unit 2 path as a potential source of post-accident radioactive Replacement Steam release through the Auxiliary Building Ventilation Generators are installed.

Exhaust stack.

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

Executed on SEP 1 3 2012 James E. Molden K i t e Vice President, Prairie Island Nuclear Generating Plant Northern States Power Company - Minnesota Enclosure (1) cc: Administrator, Region Ill, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC State of Minnesota

ENCLOSURE 1 Additional License Conditions (Markup)

Note: The License Condition proposed herein is shown as a markup to Appendix B of the Renewed Operating License as proposed in NSPM letter dated June 22, 201 1 (ADAMS Accession No. MLI 11740145).

4 pages follow Unit 1 (B-3) - provided only for completeness (no markup)

Unit 1 (B-4) - (markup)

Unit 2 (B-3) - provided only for completeness (no markup)

Unit 2 (B-4) - (markup)

APPENDIX B ADDITIONAL CONDITIONS FACILITY OPERATING LICENSE NO. DPR-42 Aniendnient Implenientation Number Additional Conditions -

Date 158 The schedule for performing Surveillance Requirements October 31, (SRs) that are new or revised In Aniendnient No. 158 shall 2002 be as follows:

For SRs that are new in this amendment, the first performance is due at tlie end of tlie first sutveillance intewal, which begins on the date of iniplementation of tliis amendment.

For SRs that existed prlor to tlils amendment, wliose intervals of performance are being reduced, the first reduced sirrveillance interval begins irpon completion of the flrst strrvelllance performed after implementation of tliis amendment.

For SRs that existed prior-to tliis amendment that have niodifled acceptance crlleria, tlie flrst performance is due at the end of the surveillance interval that began on tlie date

. the surveillance was last pelformed prior to the irnplernentaiion of this amendment.

For SRs that existed prlor to this amendment, whose intervals of performance are being extended, the first extended strrvelllance Interval begins upon conipletion of the last surveillance performed prior to the implementation of thls amendment: '

The licensee is authorized to relooate certain Teclinioal October 31, Specification requirements previously included In 2002 Appendix A to licensee-controlled docirnients, as described in Table LR, "Less Restrictive Changes - Relocated Details," and Table R, "Relocated Specillcatlons," attached to tlie NRC staff's safety evaluation datecl July 26, 2002, Those requirements shall be relocated to tlie appropriate docunients no later than October 31, 2002.

The Alternative Source Term (AST) License Amendments Within 90 days

-- / will be impleniented after installation of the Unlt 2 after completion Repiacenient Stearn Generators (RSGs). of the outage In which tlie Unlt 2 RSGs are Installed Aniendment No,

APPENDIX B ADDITIONAL CONDITIONS FACILITY OPERATING LICENSE NO. DPR-42 Amendment Irnplenientatlon Ntrrnber Additional Conditions -

Date NSPM will provide the NRC written notification when Unit 2 Within 30 days RSG installation is complete and AST Llcense Anlendment after completion implementation has commenced, of the otrtage in whlcli the Unit 2 RSGs are installed Implement a physical plant modification or after procedure modification that will ensure the completion of 121 Laundry Fan exhaust flow path is not a the outage in potential source of post-accident radioactive which the Unit release through the Auxiliary Building 2 RSGs are Ventilation Exhaust stack. installed.

Amendment No.

APPENDIX B ADDITIONAL CONDITIONS FACILITY OPERATING LICENSE NO. DPR-60' Amendnient Implementation Number Additional Condltlons Pate 149 The schedule for pelfornilng Su~velllanceReqi~lrenients October 3 1, (SRs) that are new or revised in Amendment No. 149 shall 2002 be as follows:

For SRs that are new in this amendment, the first performance is due at the end of the flrst siltveillance interval, wiiicli begins on tlie date of implenientation of this aniendment.

For SRs that existed prior to this aniendn~ent,whose Intetvals of perforniance are belng I-educed, tlie first reduced surveillance interval begins upon completion of the first surveillance performed after iniplenientatlon of thls amendment.

For SRs that existed prior to thls amendment that have modified acceptance criteria, the first performance is due at the end of the s~~rveiliance intetval that began on tlie date the su~velllancewas last pelformed prlor to the Implenientation of this amendnient.

For SRs that existed prior to thls amendnient, whose intetvals of perforniance are helng extended, the first extended s~~tvelllance intewal begins upon conipletlon of tiie last suweillance performed prior to tlie Iniplenientation of this aniendment.

149 The licensee is autliorized to relocate cettaln Technical October 31, Specification requirements previously included in 2002 Appendix A to licensee-controlled documents, as descrlbecl in Table LR, "Less Restrictive Changes - Relocated Details," and Table R, "Relocated Specifications," attached to the NRC staff's safety eval~lationdated July 26, 2002.

Those requirements shall be relocated to the appropriate docunients no later than October 31, 2002.

The Alternative Source Term License Amendments Within 90 days

-- / will be implemented after Installation of tlie Unit 2 after conipletion Replacement Steam Generators (RSGs). of tlie outage In which tiie Unlt 2 RSGs are Installed Amendment No.

APPENDIX B ADDITIONAL CONDITIONS FACILITY OPERATING LICENSE NO. DPR-60 Amendment Imm,lementation Number Additional Condltlons Date NSPM wlll provide the NRC wrltten notlficatlon when Unlt 2 Wlthln 30 days RSG Installation Is complete and AST License Amendment after conipletlon iniplementation has commenced. of the oirtage In whlch the Unlt 2 RSGs are Installed Implement a physical plant modification or procedure modification that will ensure the completion of 121 Laundry Fan exhaust flow path is not a the outage in potential source of post-accident radioactive which the Unit release through the Auxiliary Building 2 RSGs are Ventilation Exhaust stack. installed.

Amendment No.