ML080990533

Additional Information for the Response to Request for Additional Information (RAI) Regarding Large Break Loss-of-Coolant Accident Analysis Methods

ML080990533
Person / Time
Site:	Sequoyah
Issue date:	02/29/2008
From:	James Smith Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC MD6259, TVA-SQN-TS-07-04
Download: ML080990533 (3)

Text

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Tennessee Valley Authority, Post Office Box 2000, Soddy-Daisy, Tennessee 373S41-2000 February 29, 2008 TVA-SQN-TS-07-04 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Gentlemen:

In the Matter of ) Docket No. 50-328 Tennessee Valley Authority (TVA)

SEQUOYAH NUCLEAR PLANT (SQN) - UNIT 2 - ADDITIONAL INFORMATION FOR THE RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION (RAI)

REGARDING LARGE BREAK LOSS-OF-COOLANT ACCIDENT ANALYSIS METHODS (TAC NO. MD6259)

References:

1. TVA letter to NRC dated July 26, 2007, "Sequoyah Nuclear Plant (SON) - Utit 2 - Technical Specifications (TS) Change 07-04

'Revision of Core Operating Limits Report (COLR) References for Realistic Large Break Loss of Coolant Accident Methodology"

2. TVA letter to NRC dated October 3, 2007, "Sequoyah Nuclear Plant (SQN) - Unit 2 - Technical Specifications (TS) Change 07-04

'Revision of Core Operating Limits Report (COLR) References for Realistic Large Break Loss of Coolant Accident Methodology Supplemental Information"'

3. TVA letter to NRC dated December 21, 2007, Sequoyah Nuclear Plant (SON) - Unit 2 - Response to Request for Additional Information (RAI) Regarding Large Break Loss-Of-Coolant Accident Analysis Methods (TAC NO.' MD6259)

This letter provides the results of the SON Unit 2 analysis performed with the code changes discussed in Reference 3. A number of the RAI responses in Reference 3 indicated that the SON Unit 2 realistic large break loss-of-coolant accident (RLBLOCA) analysis would be performed with a revised version of the S-RELAP5 computer code that has been modified to address NRC questions with the code (i.e., rod quench limits, Forslund-Rohsenow heat transfer coefficient limits and break size limits).

,X

U.S. Nuclear Regulatory Commission Page 2 February 29, 2008 The results of the reanalysis are summarized in Revision 01 of Topical Report No. ANP-2655(P), "Sequoyah Nuclear Plant Unit 2 Realistic Large Break LOCA Analysis" and are included in Enclosure 1. The revised results are based on .a new case set of 59 individual transient cases. The individual transient cases are based on a complete "re-seeding" of the ranged analysis parameters consistent with the realistic methodology. The results demonstrate the adequacy of the emergency core cooling system to meet the performance acceptance criteria established by 10 CFR 50.46(b).

The limiting calculated fuel peak clad temperature (POCT) established by the analysis is 2002 degrees F. This value represents a 35 degrees F increase in the previously calculated value of 1967 degrees F. The difference in the limiting PCT results from the changes in the ranged parameters in the new case sets and is within the result

-variation expected with the realistic analytical methodology,.

Portions of Enclosure 1 are proprietary to Areva Nuclear Power (NP). Enclosure 2 provides a non-proprietary version of the document contained in Enclosure 1.

Accordingly, Enclosure 3 includes a Areva NP Application for Withholding Proprietary

• Information from Public Disclosure, and an accompanying Affidavit signed by Areva NP, the owner of the information. Also included are a Proprietary Information Notice anid a Copyright Notice. The affidavit sets forth the basis on which the inrformation may h)e withheld from public disclostire b)y the Commission, and addresses with specificity the considerations listed irn paragraph (b)(4) of 10 CFR 2.390 of the Commission's regulations. TVA respectfully requests that the Areva NP proprietary information be wilhliold forn public disclosure ini accordance with 10 CFR 2.390.

If you have any questions about this change, please contact me at 843-7 170.

I declare under penalty of perjury that the foregoing is true and correct. Executed on this 29th day of February, 2008.

Sincerely, James D. Smith Manager, Site Licensing and Industry Affairs

Enclosures:

1. Proprietary Version of SON's Plant Specific Topical

2. Non-Proprietary Version of SQN's Plant Specific Topical

3. Areva NP Affidavit for Withholding of Proprietary Information

U.S. Nuclear Regulatory Commission Page 2 February 29, 2008 cc (Enclosures):

Mr. Thomas H. Boyce, Senior Project Manager U.S. Nuclear Regulatory Commission Mail Stop 08G-9a One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2739 Mr. Lawrence E. Nanney, Director Division of Radiological Health Third Floor L&C Annex 401 Church Street Nashville, Tennessee 37243-1532