ML12310A012

Request for Additional Information

ML12310A012
Person / Time
Site:	Davis Besse
Issue date:	11/16/2012
From:	Michael Mahoney Plant Licensing Branch III
To:	Lieb R FirstEnergy Nuclear Operating Co
Michael Mahoney, NRR/DORL 415-3867
References
TAC ME8411
Download: ML12310A012 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 16, 2012 Mr. Ray Lieb Site Vice President FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station Mail Stop A-DB-3080 5501 North State Route 2 Oak Harbor, OH 43449-9760

SUBJECT:

DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO.1 - REQUEST FOR ADDITIONAL INFORMATION REGARDING DAVIS-BESSE NOTIFICATION OF SIGNIFICANT CHANGE TO THE LARGE-BREAK LOSS-OF-COOLANT ACCIDENT EMERGENCY CORE COOLING MODEL IN ACCORDANCE WITH TITLE 10 OF THE CODE OF FEDERAL REGULATIONS, SECTION 50.46 (a)(3)

(TAC ME8411)

Dear Mr. Leib:

By letter dated March 16, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12076A237), FirstEnergy Nuclear Operating Company (FENOC) submitted a notification of a significant change to the large-break loss-of-coolant accident emergency core cooling model in accordance with Title 10 of the Code of Federal Regulations, Section 50.45(a)(3) for Davis-Sesse Nuclear Power Station, Unit 1.

The U.S. Nuclear Regulatory Commission (NRC) staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure to this letter. During a discussion with your staff on October 29,2012, it was agreed that FENOC would provide a response within 45 days from the date of this letter.

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

R. Leib -2 If circumstances result in the need to revise the requested response date, please contact me at (301) 415-3867.

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Michael Mahoney, Project anager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-346

Enclosure:

Request for Additional Information cc w/encl: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION DAVIS-BESSE NUCLEAR POWER STATION, UNIT 1 30-DAY REPORT FOR EMERGENCY CORE COOLING SYSTEM MODEL CHANGES PURSUANT TO THE REQUIREMENTS OF 10 CFR 50.46 DOCKET NO. 50-346 By letter to the U.S. Nuclear Regulatory Commission (NRC) dated March 16, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12076A237),

FirstEnergy Nuclear Operating Company (FENOC), the licensee for Davis-Besse Nuclear Power Station, Unit 1 (DBNPS), sent a notice reporting a change or error discovered in an evaluation model, or in the application of such a model, that affects the peak cladding temperature (PCT) calculation.

This report was submitted pursuant to the requirements of Title 10 of the Code of Federal Regulations (CFR), Section 50.46, which requires, in part, that licensees report a change in the evaluation model used if a significant change in PCT results in a greater than 50 degrees Fahrenheit (OF) change. The intent of this requirement is to enable the NRC staff to review and evaluate the safety significance of this change (See Federal Register, Volume 53, No. 180, pp.

35996-36005).

FENOC stated in their March 16,2012, letter that there were two issues which satisfy the criteria of a significant change or error as defined by 10 CFR 50.46(a)(3)(i). The issues, as characterized by FENOC, were: (1) an application error, and (2) a modeling change.

The NRC staff has determined that the additional information requested below is needed to complete its review:

1. There are two changes to PCT for large-break loss-of-coolant accident (LBLOCA) analysis discussed in the report submitted by the licensee. The first change is an Evaluation Model (EM) application error in the determination of the end of emergency core cooling system (ECCS) bypass, which resulted in an 80 of decrease in PCT. The second change is an EM modeling change to include the effects of the upper plenum column weldments, which resulted in an 80 of increase in PCT.

Provide the analysis that lead to each change having an 80 "F change in PCT.

2. 10 CFR 50.46(a)(3)(ii) states: " ... If the change or error is significant, the applicant or licensee shall provide this report within 30 days and include with the report a proposed schedule for providing a reanalysis or taking other action as may be needed to show compliance with 50.46 requirements ... "

The PCT for LBLOCA for DBNPS has changed by an absolute value of 160 OF since the analysis was performed. Simply reporting the changes and errors in the methodology does not satisfy the intent of the regulation.

Justify not providing a schedule for reanalYSis or taking other action to show compliance with 10 CFR 50.46.

ENCLOSURE

R. Lieb -2 If circumstances result in the need to revise the requested response date, please contact me at (301) 415-3867.

Sincerely, IRAI Michael Mahoney, Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket 1\10. 50-346

Enclosure:

Request for Additional Information cc w/encl: Distribution via Listserv DISTRIBUTION:

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