ML110341352

Request for Additional Information Related to License Amendment Regarding Ultimate Heat Sink

ML110341352
Person / Time
Site:	Byron
Issue date:	02/14/2011
From:	Michael Mahoney Plant Licensing Branch III
To:	Pacilio M Exelon Nuclear
mahoney, m NRR/DORL/LPLIII-2 415-3867
References
TAC ME1669, TAC ME1670
Download: ML110341352 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 14, 2011 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville. IL 60555 SUB~IECT: BYRON STATION, UNIT NOS. 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO LICENSE AMENDMENT REGARDING ULTIMATE HEAT SINK (TAC NOS. ME1669 AND ME1670)

Dear Mr. Pacilio:

By letter to the Nuclear Regulatory Commission (NRC) dated June 30, 2009, as supplemented by letters dated January 25, July 1. and November 11.2010 (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML091831253, ML100280553.

ML101830041 , and ML103120556, respectively). Exelon Generation Company, LLC (the licensee), submitted a license amendment request for the Byron Station, Unit Nos. 1 and 2, to revise Technical Specification 3.7.9, "Ultimate Heat Sink (UHS)," to add additional essential service water (SX) cooling tower fan requirements as a function of SX pump discharge temperature to reflect the results of a revised analysis for the UHS.

The NRC staff is reviewing your submittals, and has determined that additional information is required to complete its review. The specific information requested is addressed in the enclosure to this letter. During a discussion with your staff on February 9, 2011, it was agreed that you would provide a response within 30 days from the date of this letter.

Please note that if you do not respond to this letter by the agreed-upon date or provide an acceptable alternate date in writing, we may reject your request for approval under the provisions of 10 CFR 2.108.

The NRC staff considers that timely responses to requests for additional information help ensure that sufficient time is available for the NRC staff to review and contribute toward the NRC's goal of efficient and effective use of staff resources.

M. Pacilio -2 If circumstances result in the need to revise the requested response date, please contact me at 301-415-3867 or Nicholas DiFrancesco at 301-415-1115.

/

ichael Mahoney, Project Man~

Plant Licensing Branch 111-2 Division of Operating Reactor licensing Office of Nuclear Reactor Regulation Docket No. STN 50-454 and STN 50-455

Enclosure:

Request for Additional Information cc w/encl: Distribution via

REQUEST FOR ADDITIONAL INFORMATION BYRON STATION, UNIT NOS. 1 AND 2 EXELON GENERATION COMPANY, LLC DOCKET NOS. 50-454 AND 50-455 The Nuclear Regulatory Commission (NRC) staff is reviewing Exelon Generation Company, LLC's (the licensee) license amendment request (LAR) for the Byron Station, Unit Nos. 1 and 2 (Byron) dated June 30,2009, as supplemented by letters dated January 25, July 1, and November 11, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML091831253, ML100280553, ML101830041, and ML103120556, respectively).

The LAR requests to revise Technical Specification (TS) 3.7.9, "Ultimate Heat Sink (UHS)," to add additional essential service water (SX) cooling tower fan requirements as a function of SX pump discharge temperature to reflect the results of a revised analysis for the UHS.

The NRC staff has determined that the following additional information is required to complete its review.

1. The UHS is required to be OPERABLE in MODES 1 through 4. Eight cooling tower fans running in fast speed are necessary to ensure basin temperature does not reach 100°F following a LOCA 1I0ss of offsite power at one unit concurrent with the safe shutdown from maximum power of the other unit under bounding conditions. When 8 fans are not OPERABLE and in fast speed while the plant is in MODES 1 through 4 under bounding conditions, LCO 3.7.9 is not met. As an alternative to shutting down the reactor, the TS allow entry into LCO 3.7.9 Condition A and performance of REQUIRED ACTIONS A.1 and A.2.

The Facility Operating License (FOL) for Byron contains a set of rules for the use and application of Byron TS's. The BACKGROUND section on Page 1.3-1 of Byron TS states "The ACTIONS associated with an LCO state Conditions that typically describe the ways in which the requirements of the LCO can fail to be met. Specified with each stated Condition are Required Action(s) and Completion Time(s)."

The proposed TS 3.7.9 changes do not appear to conform to the use and application section of Byron TS. That is, the proposed Conditions do not describe the ways in which cooling tower fan requirements can fail to be met.

Explain why this unusual format is required, or provide revised proposed TS that conform to the TS use and application section of the Byron FOL ENCLOSURE

M. Pacilio -2 If circumstances result in the need to revise the requested response date, please contact me at 301-415-3867 or Nicholas DiFrancesco at 301-415-1115.

Sincerely, IRAJ Michael Mahoney, Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor licensing Office of Nuclear Reactor Regulation Docket No. STN 50-454 and STN 50-455

Enclosure:

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PUBLIC LPL3-2 RlF RidsNrrPMByron Resource RidsNrrLASRohrer Resource RidsOgcRp Resource RidsAcrsAcnw_MailCTR Resource RidsNrrDorlDpr Resource RidsRgn3MailCenter Resource NDiFrancesco, NRR RidsNrrDirsltsb Resource RidsNrrDssSnpb Resource ADAMS AcceSSion No. ML110341352 *Bsy Memo Dae t d OFFICE LPL3-2IPM LPL3-2/LA LPL3-2/BC DIRS/ITSB/BC LPL3-2/PM NAME MMahoney SRohrer RCarlson RElliott* MMahoney (EBrown for) 2/14/11 DATE 2/8/11 2/8/11 *2/4/11 2114/11 OFFICIAL RECORD COPY