ML13025A298

Request for Additional Information Concerning the Allowance for Nexus Methodology in the Preparation of the Core Operating Limits Report

ML13025A298
Person / Time
Site:	Farley
Issue date:	01/30/2013
From:	Ellen Brown Plant Licensing Branch II
To:	Ajluni M Southern Nuclear Operating Co
Martin R Brown E
References
TAC ME9244, TAC ME9245
Download: ML13025A298 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 January 30, 2013 Mr. M. J. Ajluni Nuclear Licensing Director Southern Nuclear Operating Company, Inc.

40 Inverness Center Parkway Bin - 038 Birmingham, AL 35201-1295

SUBJECT:

JOSEPH M. FARLEY NUCLEAR PLANT, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION CONCERNING THE ALLOWANCE FOR NEXUS METHODOLOGY IN THE PREPARATION OF THE CORE OPERATING LIMITS REPORT (TAC NOS. ME9244 AND ME9245)

Dear Mr. Ajluni:

By letter dated August 14, 2012, Southern Nuclear Company (SNC or the licensee), submitted a license amendment request for the Joseph M. Farley Nuclear Plant (FNP). The proposed amendments would revise Technical Specification (TS) 5.6.5, "Core Operating Limits Report (COLR)," to reference and allow use of Westinghouse WCAP-16045-P-A, Addendum i-A, "Qualification of the NEXUS Nuclear Data Methodology," to determine core operating limits.

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. Ryan Joyce of your staff on January 24, 2013, and it was agreed that SNC would respond within 30 days of issuance of this letter. If you have any questions, please feel free to contact me at (301) 415-2315.

Sincerely IRA!

Eva A. Brown, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-348 and 50-364

Enclosure:

Request for Additional Information cc wI encl: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION ALLOWANCE FOR NEXUS METHODOLOGY IN THE PREPARATION OF THE CORE OPERATING LIMITS REPORT SOUTHERN NUCLEAR COMPANY JOSEPH M. FARLEY NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50- 384 AND 50-364

1. U.S. Nuclear Regulatory Commission (NRC) Generic Letter (GL) 88-16, "Removal of Cycle-Specific Parameter Limits from Technical Specifications," indicates that it is acceptable for licensees to control reactor physics parameter limits by specifying the calculation methodology. The discussion in the GL refers conceptually to the acceptability of licensee control of such parameters based on the use of a specific methodology.

Examples include:

" ... provided that these changes are determined using an NRC-approved methodology ... "

" ... using the specified methodology ... "

As presently worded, the proposed Technical Specifications (TSs) amendment would permit the Joseph M. Farley Nuclear Plant, Units 1 and 2 (Farley) licensees to choose either of two methods; however, the proposed amendment does not explain how this selection would be made. The proposal creates, in effect, a new, more ambiguous, method in which either previous method may be applied. The NRC staff is unable to determine that this proposal is consistent with GL 88-16 guidance. Please propose a revision to TS 5.6.5 that provides for a single, unambiguous method that describes how TS Limiting Condition for Operation (LCO) 3.9.1 will be determined.

2. The NRC staff safety evaluation approving WCAP-16045-P-A, Addendum 1-A, "Qualification of the NEXUS Nuclear Data Methodology," states that the scope of the staff review was "limited only to the coupling between PARAGON and ANC." This statement implies that one must use PARAGON in order to implement NEXUS. The PARAGON methodology description is substantially more detailed, and includes descriptions of the numerical techniques that are used to solve the transport equation.

Please explain how the NEXUS methodology will be applied, given that the proposed TS revision does not include reference to the PARAGON methodology. If appropriate, propose a revision to TS 5.6.5 that refers to methodologies describing both PARAGON and NEXUS.

Enclosure

-2

3. Identify any other core operating limits and safety analyses that will be performed or determined using inputs from the NEXUS methodology, such as a loss of coolant accident (LOCA) or boron concentration limits. In addition, discuss any potential impacts on post-LOCA long term cooling emergency operating procedure timing for boric acid precipitation and the action time for switching to simultaneous injection as well as the potential for return to power following a large break LOCA during early reflood when highly sub-cooled water at its minimum temperature enters the lower portion of the core.

January 30, 2013 Mr. M. J. Ajluni Nuclear Licensing Director Southern Nuclear Operating Company, Inc.

40 Inverness Center Parkway Bin - 038 Birmingham, AL 35201-1295

SUBJECT:

JOSEPH M. FARLEY NUCLEAR PLANT, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION CONCERNING THE ALLOWANCE FOR NEXUS METHODOLOGY IN THE PREPARATION OF THE CORE OPERATING LIMITS REPORT (TAC NOS. ME9244 AND ME9245)

Dear Mr. Ajluni:

By letter dated August 14, 2012, Southern Nuclear Company (SNC or the licensee), submitted a license amendment request for the Joseph M. Farley Nuclear Plant (FNP). The proposed amendments would revise Technical Specification (TS) 5.6.5, "Core Operating Limits Report (COLR)," to reference and allow use of Westinghouse WCAP-16045-P-A, Addendum i-A, "Qualification of the NEXUS Nuclear Data Methodology," to determine core operating limits.

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. Ryan Joyce of your staff on January 24, 2013, and it was agreed that SNC would respond within 30 days of issuance of this letter. If you have any questions, please feel free to contact me at (301) 415-2315.

Sincerely IRA!

Eva A. Brown, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-348 and 50-364

Enclosure:

Request for Additional Information cc wi encl: Distribution via Listserv DISTRIBUTION:

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