NLS2008078, Response to Request for Additional Information Reactor Equipment Cooling System

Response to Request for Additional Information Reactor Equipment Cooling System

ML082700547
Person / Time
Site:	Cooper
Issue date:	09/19/2008
From:	Minahan S Nebraska Public Power District (NPPD)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NLS2008078, TAC MD8374
Download: ML082700547 (5)

Text

N Nebraska Public Power District "Always there when you need us" 50.90 NLS2008078 September 19, 2008 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001

Subject:

Response to Nuclear Regulatory Commission Request for Additional Information Re: Reactor Equipment Cooling System (TAC No. MD8374)

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 August 1, 2008, "Cooper Nuclear Station - Request for Additional Information Re:

Reactor Equipment Cooling System (TAC No. MD8374)"

2. Letter from Stewart B. Minahan, Nebraska Public Power District, to the U.S. Nuclear Regulatory Commission, dated March 24, 2008, "License Amendment Request to Revise Technical Specification 3.7.3, Reactor Equipment Cooling System"

Dear Sir or Madam:

The purpose of this letter is for the Nebraska Public Power District to submit a 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 review of a license amendment request (LAR) to revise the Technical Specifications (TS) for Cooper Nuclear Station (CNS) (Reference 2). The LAR proposed revisions to TS 3.7.3, Reactor Equipment Cooling System.

The response to the specific questions in the RAI is provided in Attachment 1. 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.

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

NLS2008078 Page 2 of 2 If you have any questions concerning this matter, please contact David W. Van Der Kamp, Licensing Manager, at (402) 825-2904.

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

Executed on /* 'fl'7 r (date)

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

/rr 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/o attachment CNS Records w/ attachment

NLS2008078 Page 1 of 2 Attachment 1 Response to Nuclear Regulatory Commission Request for Additional Information Re: Reactor Equipment Cooling System (TAC No. MD8374)

Cooper Nuclear Station, Docket No. 50-298, DPR-46 NRC Question #1 The LAR stated that operator action to align the Service Water (SW) system to the REC critical loops following a loss of the REC system during a loss of coolant accident (LOCA) can be performed within an hour. [a] How much time does the operatoractually have available to realign the SW system to provide cooling to the Emergency Core Cooling System pump rooms if the REC system is not available or determined to be inoperable during a LOCA? [b] How was the one hour time frame determined? [c] Does the assumed available time of one hour bound the recent (June 30, 2008) Measurement Uncertainty Recapturepower uprate approved by the NRC?

Response

[a] As explained in the response to part [b] below, the period of one hour to align the SW System to the Reactor Equipment Cooling (REC) System was an assumption in the calculations. The operators are able to make the alignment within one hour. Based on the acceptable results of the one hour, some additional time may be available. However, this has not been quantified. Since the operators are able to make this alignment within one hour, additional time is not needed.

The license amendment request (LAR) dated March 24, 2008, discussed the performance of scenarios on the Cooper Nuclear Station (CNS) simulator to demonstrate the ability of the control room staff to make this alignment within one hour. As noted in the LAR, these scenarios successfully demonstrated that ability.

[b] The one-hour period was determined based on it being identified as sufficient time for the control room staff to recognize the need to align the SW System to the REC critical loops and to make the alignment, in conjunction with taking the other actions required to mitigate the accident. Based on one hour being sufficient time to make this system alignment, the one hour was used as an assumption in CNS calculation NEDC 00-095E, Revision 2, "CNS Reactor Building Post-LOCA Heating Analysis," performed to determine the impact of the revised SW-to-REC alignment process on temperatures in the Reactor Building. Because the system alignment is performed from the Main Control Room and the Cable Spreading Room, areas which are readily accessible in any plant condition, making the system alignment within the time assumed in the analysis is not a challenge. The one-hour time period is not a derived value.

[c] The one-hour period does bound the MUR power uprate. This is based on the CNS post-LOCA design basis containment thermal response analysis-of-record having been performed assuming an initial reactor power of 102% of licensed power level. The Emergency Core Cooling System evaluation model includes a 2% margin to allow for uncertainties in core thermal power measurement in accordance with Appendix K of 10 CFR Part 50. NEDC 00-095E, Revision 2,

NLS2008078 Page 2 of 2 performed with the assumption of one hour to align SW to REC critical loops, is based on the post-LOCA design input at 102% power. As a result, this calculation remains bounding for the MUR power uprate with respect to the Reactor Building thermal environment.

NRC Question #2 Discuss whether the operatingcrews will have an opportunity during operator trainingto perform a variety of scenarios involving the recognition of the loss of the REC system and realignment of the SW system to the REC system (in addition to long-term recoveryfrom a LOCA).

Response

Licensed personnel at CNS currently have had, and will continue to have, opportunities to perform a variety of scenarios involving recognition of the loss of the REC System and taking the actions to align the SW System to the critical loops of the REC System. (Use of the SW System as a backup source of cooling water to the REC System seven days after the occurrence of a LOCA was credited and made a part of the CNS licensing basis by Amendment 185, dated March 13, 2001, to the CNS operating license.)

The task of aligning the SW System to the REC critical loops is included in both the Initial License Operator Training (ILT) and the License Operator Requalification (LOR) Programs. Simulator scenarios are included as part of this training. Through the LOR Program the operators are provided simulator training on this task every two years.

Simulator training is provided in the ILT Program through two lesson plans. The two plans are titled (1) "Reactor Equipment Cooling System" [required], and (2) "Loss of All REC" [optional].

Simulator training is provided in the LOR Program through one lesson plan, titled "Turbine Equipment Cooling Heat Exchanger Tube Leak, Loss of All REC."

CNS uses the Systematic Approach to Training (SAT) identified in 10 CFR 55.59 for reactor operators and senior reactor operators to identify requalification training requirements. This process is approved by the NRC using the Institute of Nuclear Power Operation training program accreditation process.

ATTACHMENT 3 LIST OF REGULATORY COMMITMENTS@

OCATTACHMENT 3 LIST OF REGULATORY COMMITMEENTS Correspondence Number: NLS2008078 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

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