ML13155A542

Request for Additional Information - One-time Change to TS 3.6.6 Completion for an Inoperable Containment Spray Train Under Exigent Circumstances to Allow for Pump Repair - TAC MF1875

ML13155A542
Person / Time
Site:	Watts Bar
Issue date:	06/04/2013
From:	Andrew Hon Plant Licensing Branch II
To:	James Shea, Schrull E Tennessee Valley Authority
Hon A
References
TAC MF1875
Download: ML13155A542 (2)

Text

From: Hon, Andrew Sent: Tuesday, June 04, 2013 4:08 PM To: 'Shea, Joseph W'; 'Schrull, Edward Dustin'; 'tahess@tva.gov' Cc: Bettle, Jerome; Hamm, Matthew; Tate, Travis; Saba, Farideh; Quichocho, Jessie

Subject:

Request for Additional Information - one-time change to TS 3.6.6 Completion for an Inoperable Containment Spray Train Under Exigent Circumstances to allow for pump repair - TAC MF-1875 By letter dated May 22, 2013 (ADAMS NO. ML13143A166), TVA submitted a license amendment request for Watts Bar Unit-1. This amendment is for a one-time change to TS 3.6.6 Completion Time for an Inoperable Containment Spray Train from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days under Exigent Circumstances to allow for pump repair during the week of June 24, 2013.

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 proposed questions below were discussed by telephone with your staff on June 3, 2013. Your staff confirmed that these questions did not include proprietary or security-related information and agreed to provide a response in approximately a week from the date of this request for additional information (RAI). The specific information requested is as follow:

1. In your May 22, 2013 submittal, Section 3.2, Technical Specification Change Evaluation, stated that:

Based on sensitivity studies performed using the WEC LOTIC and WCOBRA/TRAC computer codes, it is estimated that the peak containment pressure could reach approximately 16.8 - 25.3 psig during a design-based accident DBA LOCA with no CS cooling available or credited.

Sufficient detail to explain the range of peak containment pressures is requested as follow:

• Were these sensitivity studies performed with the analysis of record (AOR) computer models?

• What are the input parameter changes from the design-base-accident (DBA) loss-of-coolant-accident (LOCA) AOR model that result in the 16.8 and 25.3 psig values?

• At what time in the event is the containment peak pressure reached and how long does it remain above 15 psig pressure?

• Please provide graphs of these pressure transients.

• Please provide a table of the input values from the AOR model and the changes for the 16.8 and 25.3 psig results.

It also stated that:

Therefore, even without crediting CS cooling, the predicted increase in peak containment pressure should not significantly challenge the containment integrity or result in increased leakage.

Please provide the last Integrated Leak Rate Test and combined TYPE B & C Local Leak Rate Test results (as a percent of allowable leakage -La-).

2. In your submittal, Section 2.1, Basis for Exigent Request, does not explain the reason for selecting specifically the week of June 24. 2013, to repair the pump seal. Please explain how that week was chosen and the adverse impacts of conducting the repair after the normal 30-day notice for public comments and 60-day request for hearing period under 10CFR50.91.

In Section 2.3, Justification for the Change, TVA stated The preliminary estimate for the seal replacement activity is 68 hours7.87037e-4 days <br />0.0189 hours <br />1.124339e-4 weeks <br />2.5874e-5 months <br />, not including potential discovery issues which may be encountered. Please provide following clarifications:

• What are the bases of the 68 hours7.87037e-4 days <br />0.0189 hours <br />1.124339e-4 weeks <br />2.5874e-5 months <br /> estimated to cover the seal repair items outlined in this section?

• What are the potential issues may be encountered during the seal replacement and TVAs contingency plans for these potential issues, including time estimates?

If you have any questions, please contact me.

Andy Hon, PE Project Manager (Watts Bar Nuclear Unit-1)

Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation 301-415-8480 OWFN 08E5 Mail Stop O8G-9a andrew.hon@nrc.gov