NLS2010022, Supplement to Response to NRC Request for Additional Information Re Non-Conservative Battery Resistance in Technical Specification Surveillance Requirements

Supplement to Response to NRC Request for Additional Information Re Non-Conservative Battery Resistance in Technical Specification Surveillance Requirements

ML100680486
Person / Time
Site:	Cooper
Issue date:	03/05/2010
From:	Minahan S Nebraska Public Power District (NPPD)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NLS2010022, TAC ME0848
Download: ML100680486 (4)

Text

H Nebraska Public Power District "Always there when you need us" 50.90 NLS2010022 March 5, 2010 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001

Subject:

Supplement to Response to Nuclear Regulatory Commission Request for Additional Information Re: Non-Conservative Battery Resistance in Technical Specification Surveillance Requirements (TAC No. ME0848)

Cooper Nuclear Station; Docket No. 50-298, DPR-46

References:

1. Letter from Carl F. Lyon, U.S. Nuclear Regulatory Commission, to Stewart B. Minahan, Nebraska Public Power District, dated November 25, 2009, "Cooper Nuclear Station - Request for Additional Information Re:

Battery Resistance Surveillance Requirements (TAC No. ME0848)"

2. Letter from Stewart B. Minahan, Nebraska Public Power District, to the U.S. Nuclear Regulatory Commission, dated March 11, 2009, "License Amendment Request to Revise Nonconservative Battery Resistance Technical Specification Surveillance Requirements"

3. Letter from Brian J. O'Grady, Nebraska Public Power District, to the U.S.

Nuclear Regulatory Commission, dated December 21, 2009, "Response to Nuclear Regulatory Commission Request for Additional Information Re:

Non-Conservative Battery Resistance in Technical Specification Surveillance Requirements (TAC No. ME0848)"

Dear Sir or Madam:

The purpose of this letter is for Nebraska Public Power District to resubmit a portion of our response to a request for additional information (RAI) from the Nuclear Regulatory Commission (NRC) (Reference 1). The RAI requested information in support of the NRC's review of a license amendment request for the Cooper Nuclear Station (CNS) facility Operating License and Technical Specifications (TS) to revise the non-conservative battery resistance in the TS Surveillance Requirements (Reference 2). In a telephone call on February 4, 2010, the NRC requested CNS to supplement our response to Question #2 (Reference 3) with additional information.

O9 I COOPER NUCLEAR STATION1 P.O. Box 98 / Brownville, NE 68321-0098 Telephone: (402) 825-3811 / Fax: (402) 825-5211 www.nppd.com K, )

NLS2010022 Page 2 of 2 The response to the specific RAI question is provided in the Attachment. No regulatory commitments are made in this submittal.

The information submitted by this response to the RAI does not change the conclusions or the basis of the no significant hazards consideration evaluation provided with Reference 2.

If you have any questions concerning this matter, please contact David Van Der Kamp, Licensing Manager, at (402) 825-2904.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on 2/A f.2_5- a01O (date)

Sincerely, ftewart B. Minahan Vice President - Nuclear and Chief Nuclear Officer

/em Attachment cc: Regional Administrator w/ attachment USNRC - Region IV Cooper Project Manager w/ attachment USNRC - NRR Project Directorate IV-1 Senior Resident Inspector w/ attachment USNRC - CNS Nebraska Health and Human Services w/ attachment Department of Regulation and Licensure NPG Distribution w/ attachment CNS Records w/ attachment

NLS2010022 Attachment Page 1 of 1 Supplement to Response to Nuclear Regulatory Commission Request for Additional Information Re: Non-Conservative Battery Resistance in Technical Specification Surveillance Requirements (TAC No. ME0848)

Cooper Nuclear Station; Docket No. 50-298, DPR-46

2. In the Revision Summary Section of the calculations,the NRC staff notes that the Aging Coefficient is raisedfrom 0. 80 (80 percent)to 0.90 (90 percent)consistent with TS Surveillance Requirement (SR) 3.8.4.8. Describe the impact of this change on the expected life of CNS batteries (e.g., conclusions drawnfrom the battery life versus performance curve for the batteries).

Response

In Reference 3, Nebraska Public Power District (NPPD) responded that the expected life for the Cooper Nuclear Station (CNS) batteries will be shorter, and that it will be managed as part of the CNS Battery Program. As discussed in the phone call of February 4, 2010, the following information is provided to supplement this response, and is being included in the Bases for Technical Specification 3.8.4 and Surveillance Requirement (SR) 3.8.4.8.

The batteries for DC electrical power sub-systems were originally sized to produce required capacity at 80% of nameplate rating, corresponding to warranted capacity at the end of a nominal 20 year service cycle. However, as loads have increasedover time, battery required capacity is now closer to 90%. Our battery vendor does not estimate battery life for 90%

capacity. Therefore, NPPD exercised engineering judgment to conservatively establish 15 years as the point at which the batteries reach 85% of expected life, and conservatively defined battery degradation to be when capacity drops by more than 5% relative to the capacity on the previous performance test or when the battery capacity reaches less than or equal to 95% of manufacturers rating. This battery age of 15 years advances by 2 years the point at which the frequency for performing battery capacity verification per SR 3.8.4.8 changes from 60 months to 18 months. Two years is considered a sufficient reduction to account for the increased loading on the batteries. The new, more restrictive, definition of battery degradation is a graded approach to ensure that decisions to replace batteries are made before the batteries reach the 90% capacity limit of SR 3.8.4.8.

4 ATTACHMENT 3 LIST OF REGULATORY COMMITMENTS© 4

ATTACHMENT 3 LIST OF REGULATORY COMMITMENTS© Correspondence Number: NLS2010022 The following table identifies those actions committed to by Nebraska Public Power District (NPPD) in this document. Any other actions discussed in the submittal represent intended or planned actions by NPPD. They are described for information only and are not regulatory commitments. Please notify the Licensing Manager at Cooper Nuclear Station of any questions regarding this document or any associated regulatory commitments.

COMMITMENT COMMITTED DATE COMMITMENT NUMBER OR OUTAGE None I

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