ML070370281

Nuclear Plant, Unit 1 - Proposed Extended Power Uprate Fuels License Conditions (TAC No. MD5262) (TS-431-S)

ML070370281
Person / Time
Site:	Browns Ferry
Issue date:	06/24/2008
From:	Giitter J Plant Licensing Branch III-2
To:	Campbell W Tennessee Valley Authority
Brown, E, NRR/DORL, 415-2315
References
TAC MD5262, TS-431-S
Download: ML070370281 (5)

Text

June 24, 2008 Mr. William R. Campbell, Jr.

Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

BROWNS FERRY NUCLEAR PLANT, UNIT 1 PROPOSED EXTENDED POWER UPRATE FUELS LICENSE CONDITION (TAC NO. MD5262)

(TS-431-S)

Dear Mr. Campbell:

By letter dated June 24, 2004, the Tennessee Valley Authority (TVA, the licensee) submitted an amendment request for Browns Ferry Nuclear Plant (BFN), Unit 2 and 3, as supplemented by letters dated August 23, 2004; February 23, April 25, June 6, and December 19, 2005; February 1 and 28, March 7, 9, 23, and 31, April 13, May 5 and 11, June 12, 15, 23, and 27, July 6, 21, 24, 26, and 31, December 1, 5, 11, and 21, 2006; January 31, February 16, and 26, April 6, 18, and 24, March 6, July 27, August 13, and 21, September 24, November 15 and 21, and December 14, 2007; January 25, February 11 and 21, March 6, April 4, and May 1, 2008.

The proposed amendment would change the operating license to increase the maximum authorized power level from 3458 to 3952 megawatts thermal. These changes represent an increase of approximately 15 percent above the current maximum authorized power level for BFN Unit 1.

Because Unit 1 restarted in May 2007, the core (Cycles 7 and 8) designs are atypical. The current Cycle 7 core load consists predominantly of fresh GE14 and GE13 fuel bundles, while the core periphery is loaded with GE13 and GE14 fuel bundles that were irradiated in Units 2 and 3. However, for some bundles, the enrichment in the fresh fuel is lower than the normal extended power uprate (EPU) core batch fraction. For Cycle 8, the core will start with a large fraction of once-burned fuel, with the potential of being at peak reactivity.

Void Quality To implement the proposed EPU, a higher number of maximum-powered bundles are loaded into the core and the power of the average bundles is also increased, making the core radial power distribution flatter. Due to the increased two-phase pressure drop and higher coolant voiding, the flow in the maximum powered bundles decreases. This effect leads to a higher bundle power-to-flow ratio and higher exit void fractions. Since the maximum powered bundles set the thermal limits, EPU operation reduces the margins to thermal limits.

W. Campbell, Jr.

For BFN, TVA used a methodology consistent with that presented in licensing topical report LTR 33173-P, Applicability of GE Methods to Expanded Operating Domains, to address the uncertainties in the fuel vendors code given the expanded operating domain.

The NRC staff has determined that the reported accuracy in the topical report for the void quality correlation is not sufficiently supported by valid data. Additional measurement data is needed to both validate the correlation and develop the appropriate correlation uncertainty levels. Therefore, additional margin is required to address the potential inaccuracy of the coupled neutron and thermal-hydraulic predictions during steady state, transient, and accident conditions. To provide this additional margin and account for the correlation uncertainty levels, the NRC staff proposes the following as License Condition (LC) 2.(C)8:

Prior to operating at thermal power greater than 3458 megawatts thermal, the limiting operating limit minimum critical power ratio shall be established using an additional margin of 0.01 to address analyses uncertainties. This additional margin shall be maintained until additional validated measurement data is provided to the NRC in order to verify the calculated void quality correlation.

The NRC staff is requesting a response to the above license condition indicating TVAs understanding within 30 days of the issuance of this letter. It should be noted, however, that your acceptance does not constitute completion of the NRC staffs review of the EPU application and the content of the condition may change based on any subsequent information provided.

If you have any comments, please contact Ms. Eva Brown at 301-415-2315.

Sincerely,

/RA/

Joseph Giitter, Director Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-259 cc: See next page

ML070370281 NRR-106 OFFICE LPLII-2/PM LPLII-2/LA Ades/DSS/D Tech Ed NAME EBrown BClayton WRuland HChang DATE 6/24/08 6/10/08 6/6/08 3/22/08 OFFICE OGC DORL/LPL2-2/BC DORL/D NAME MZobler TBoyce JGiitter DATE 4/10/07 6/23/08 6/24/08

Page 1 of 2 Tennessee Valley Authority BROWNS FERRY NUCLEAR PLANT cc:

Mr. Ashok S. Bhatnagar Senior Vice President Nuclear Generation Development and Construction Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Vice President Nuclear Support Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. H. Rick Rogers Vice President Nuclear Engineering & Technical Services Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. D. Tony Langley, Manager Licensing and Industry Affairs Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Mr R. G. (Rusty) West, Site Vice President Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 General Counsel Tennessee Valley Authority 6A West Tower 400 West Summit Hill Drive Knoxville, TN 37902 Mr. John C. Fornicola General Manager Nuclear Assurance Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Ms. Beth A. Wetzel, Manager Corporate Nuclear Licensing and Industry Affairs Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. James E. Emens, Jr.

Supervisor, Nuclear Site Licensing Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Mr. James B. Baptist Browns Ferry Senior Project Engineer Division of Reactor Projects, Branch 6 U.S. Nuclear Regulatory Commission 61 Forsyth Street, SW.

Suite 24T85 Atlanta, GA 30303-8931 Mr. Tomy A. Nazario Browns Ferry Project Engineer Division of Reactor Projects, Branch 6 U.S. Nuclear Regulatory Commission 61 Forsyth Street, SW.

Suite 24T85 Atlanta, GA 30303-8931 Senior Resident Inspector U.S. Nuclear Regulatory Commission Browns Ferry Nuclear Plant 10833 Shaw Road Athens, AL 35611-6970

Page 2 of 2 State Health Officer Alabama Dept. of Public Health RSA Tower - Administration Suite 1552 P.O. Box 303017 Montgomery, AL 36130-3017 Chairman Limestone County Commission 310 West Washington Street Athens, AL 35611 Mr. Larry E. Nicholson., General Manager Performance Improvement Tennessee Valley Authority 3R Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. Michael A. Purcell Senior Licensing Manager Nuclear Power Group Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801