ML082820038

Brown Ferry, Units 1, 2 and 3, Request for Additional Information for Extended Power Uprate-Round 21 (TS-431 and TS-418)

ML082820038
Person / Time
Site:	Browns Ferry
Issue date:	10/09/2008
From:	Ellen Brown Plant Licensing Branch II
To:	Campbell W Tennessee Valley Authority
Brown E, NRR/DORL, 415-2315
References
TAC MD5262, TAC MD5263, TAC MD5264, TS-418, TS-431
Download: ML082820038 (5)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 9, 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, UNITS 1,2, AND 3 - REQUEST FOR ADDITIONAL INFORMATION FOR EXTENDED POWER UPRATE - ROUND 21 (TAC NOS. MD5262, MD5263 AND MD5264) (TS-431 AND TS-418)

Dear Mr. Campbell:

By letter dated June 24, 2004, the Tennessee Valley Authority submitted an amendment request for Browns Ferry Nuclear Plant (BFN), Units 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, and 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 9, May 1, June 16, August 15, September 2 and 19, 2008. The proposed amendment would change the BFI\! operating licenses for Units 1 and 2 to increase the maximum authorized power level by approximately 15 percent.

A response to the enclosed Request for Additional Information (RAI) is needed before the Nuclear Regulatory Commission staff can complete the review. This request was discussed with Mr. James Emens of your staff on October 1, 2008, and it was agreed that TVA would respond by October 17, 2008.

If you have any questions, please contact me at (301) 415-2315.

Sincerely,

~~~,1::ect Plant Licensing Branch 11-2 Manager Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-259, 260, and 50-296

Enclosure:

RAI cc w/enclosure: See next page

Tennessee Valley Authority BROWNS FERRY NUCLEAR PLANT cc:

Senior Resident Inspector U.S. Nuclear Regulatory Commission Browns Ferry Nuclear Plant 10833 Shaw Road Athens, AL 35611-6970 Chairman Limestone County Commission 310 West Washington Street Athens, AL 35611 Additional Distribution via ListServ

REQUEST FOR ADDITIONAL INFORMATION EXTENDED POWER UPRATE (EPU)

ROUND 21 TENNESSEE VALLEY AUTHORITY (TVA)

BROWNS FERRY NUCLEAR PLANT, UNITS 1,2 AND 3 DOCKET NOS. 50- 259, 50-260, AND 50-296 EMCB (Unit 1 Only) 198. In reference to the September 2,2008, response for Unit 1 to EMCB-181, explain whether the electrical interference check (EIC) signal at low flow (LF) conditions is the same as at the current license thermal power (CLTP) conditions. If so, provide justification, otherwise provide a comparison of the two signals and confirm that the difference is accounted for in estimating the fluctuating pressure signal [(CLTP-EIS)

(LF-EIS)].

(Unit 2 Only) 155. In the September 2,2008, response for Unit 2 to EMCB-147, it appears that TVA subtracts the EIC signal from the LF signal and treats the difference as mechanical noise (LF-EIC). Then it appears that TVA subtracts the EIC signal and the mechanical noise from the CLTP signal. The resulting signal is the acoustic pressure signal. Explain whether the EIC signal subtracted from the LF signal is the same as the one subtracted from the CLTP signal. If so, please provide justification. Note that in Figures EMCB.147-1a to 147-1d, the power spectral density for the 19-percent flow rate, in the high frequency range, is higher than that for 30-percent flow rate, which implies that the EIC noise is higher at lower pump/fan speeds.

SRXB (Units 2 and 3) 128. Provide a discussion of the impact of channel bow on the critical power performance for Units 2 and 3 at EPU conditions. This discussion should include the following:

a. The effect of the EPU neutron spectrum on channel bow mechanisms,

b. The appropriateness of the channel bow statistics,

c. Characterization of the susceptibility of Units 2 and 3 to abnormal channel bow,

d. Any channel bow monitoring methods, address inward and outward bow, Enclosure

-2

e. Any conservatism in the treatment of channel bow in the safety analysis in regard to thermal margin.

f. The measures taken in regard to Service Information Letter 320, and

g. Any future plans to manage greater than expected bow based on the monitoring.

'.. ML082820038 NRR-088 OFFICE LPL2-2/PM LPL2-2/LA DE/EMCB DSS/SNPB LPL2-2/BC NAME EBrown BClayton KManoly AMendiola TBoyce by memo DATE 10/9/08 10/9/08 10/9/08 9/18/2008 10/9/08