ML13206A383

Improved Flood Mitigation System - Updated Strategy for FLEX Equipment Storage

ML13206A383
Person / Time
Site:	Watts Bar
Issue date:	07/15/2013
From:	James Shea Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML13206A383 (3)

Text

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 July 15, 2013 10 CFR 50.4 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 1 Facility Operating License No. NPF-90 NRC Docket No. 50-390 Watts Bar Nuclear Plant, Unit 2 Construction Permit No. CPPR-92 NRC Docket No. 50-391

Subject:

Improved Flood Mitigation System - Updated Strategy for FLEX Equipment Storage at Watts Bar Nuclear Plant

References:

1. IVA letter, "Commitment to Install Improved Flood Mitigation Systems,"

dated April 16, 2013

2. TVA letter, "Tennessee Valley Authority (TVA) - Overall Integrated Plan in Response to the March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order EA-1 2-049) for Watts Bar Nuclear Plant," dated February 28, 2013

3. WVA letter, "Progress Update on Improved Flood Mitigation System Project," dated July 1, 2013 By letter dated April 16, 2013, Tennessee Valley Authority (TVA) committed to install improved flood mitigation systems at the Sequoyah Nuclear Power Plant (SQN),

Units 1 and 2, and the Watts Bar Nuclear Plant (WBN), Units 1 and 2 (Reference 1). In the letter, WVA committed to complete implementation of the improved flood mitigation systems at SQN and WBN by December 31, 2016. TVA also committed to submit an updated strategy for FLEX equipment storage at WBN, Units 1 and 2 by June 30, 2013.

U.S. Nuclear Regulatory Commission Page 2 July 15, 2013 In the April 16, 2013 letter, TVA described incorporating improvements to flood mitigation at SQN and WBN through the installation of new components and utilizing certain elements of the Fukushima Dai-ichi mitigation equipment (FLEX). During a public meeting on June 27, 2013, WVA briefed the NRC regarding the status of the improved flood mitigation project. During the meeting, TVA noted that for WBN, one consideration for evaluating alternatives to the design of the structure to house key components of the flood mitigation system was to reduce the potential impacts and risks to the schedule for implementing the strategies described in TVA's February 28, 2013 submittal associated with compliance with NRC Order EA-12-049, "Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Effective Immediately),"

(Reference 2). TVA noted that this was especially critical for assuring compliance with commitments in the February 28, 2013 letter for the WBN site. During the meeting, TVA revised the commitment to Commitment 3 of the Enclosure from Reference 1 to provide an updated strategy for the FLEX equipment storage building by June 30, 2013. An update to the strategy for WBN FLEX equipment storage will be provided by July 15, 2013. A summary of the meeting, including the revised commitment, was provided in a July 1, 2013 letter to NRC (Reference 3).

The purpose of this letter is to provide the updated strategy for the WBN FLEX equipment storage building consistent with Commitment 3 in Enclosure 2 of the July 1, 2013 letter.

The briefing material presented by TVA during the June 27, 2013 meeting is provided as Enclosure 1 to the July 1, 2013 letter. During the meeting, TVA advised the NRC that engineering design and project controls for the flood mitigation system project are being developed consistent with TVA's existing design and project management procedures.

Through the use of these design and project controls, TVA will provide for appropriate consideration of design alternatives while assuring design rigor and schedule adherence.

In the June 27, 2013 meeting, TVA noted that subsequent to the issuance of the April 16, 2013 letter, potential design alternatives had emerged for a number of elements of the overall flood mitigation system design as described in Enclosure I of that letter. TVA provided examples of how alternatives were being considered for the design of the structure that will house key components in the flood mitigation system, for the design of the power source for the system, and for the design of the method by which reactor decay heat will be removed during flood scenarios. These design alternatives will continue to be evaluated in the engineering design and project management process until the flood mitigation system design is finalized. To date, the design of the structure to house the flood mitigation system key systems and components have not been finalized. Consequently, to ensure timely fulfillment of the requirements of NRC Order EA-12-049, WVA will implement strategies, including schedules, for implementation of the FLEX strategy as originally set forth in the Reference 2 letter.

U.S. Nuclear Regulatory Commission Page 3 July 15, 2013 TVA's intent is to fulfill the requirements of Order EA-1 2-049 and the commitments to improve flood mitigation as separate but parallel activities. Through the updates for the FLEX project required by Order EA-12-049 and the updates committed by TVA for the flood mitigation system project committed to in the Reference 1 letter, TVA will continue to provide the NRC with information related to both of these activities, including the final strategy for use of the FLEX equipment storage building.

There are no new regulatory commitments contained in this letter. If you have questions regarding this update, please contact Kevin Casey at (423) 751-8523.

Respe ully, Vice P sdnNuclear Licensing cc:

NRC Regional Administrator - Region II NRR Director - NRC Headquarters NRC Senior Resident Inspector - Watts Bar Nuclear Plant NRR Project Manager - Watts Bar Nuclear Plant, Unit 1 NRR Project Manager - Watts Bar Nuclear Plant, Unit 2