ML14132A243

Summary of 4/24/214, Meeting with Tennessee Valley Authority Regarding Watts Bar Nuclear Plant, Unit 2, Request for Additional Information Related to License Amendment to Modify AC Power Source Technical Specifications

ML14132A243
Person / Time
Site:	Watts Bar
Issue date:	06/16/2014
From:	Justin Poole Watts Bar Special Projects Branch
To:	Tennessee Valley Authority
Poole J
References
TAC MF2549
Download: ML14132A243 (5)

Text

LICENSEE: Tennessee Valley Authority FACILITY: Watts Bar Nuclear Power Plant, Unit 1

SUMMARY

OF APRIL 24,2014, MEETINGWITH TENNESSEE VALLEY AUTHORITY REGARDING WATTS BAR NUCLEAR PLANT, UNIT 1, REQUEST FOR ADDITIONAL INFORMATION RELATED TO LICENSE AMENDMENT REQUEST TO MODIFY AC POWER SOURCE TECHNICAL SPECIFICATIONS (TAC NO. MF2549).

On April 24, 2014, a Category 1 public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of the Tennessee Valley Authority (TVA) at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, Maryland. The purpose of this meeting was for TVA to discuss with NRC recent responses to a request for additional information (RAI) related to a license amendment request (LAR). The response from TVA was submitted on April 21, 2014, which is available in the Agencywide Documents Access and Management System (ADAMS) at Accession No. ML14112A341. Attendees for this meeting are listed in the Enclosure.

By letter dated August 1, 2013 (ADAMS No. ML13220A103), TVA submitted the subject LAR for Watts Bar Nuclear Plant (WBN), Unit 1. The purpose of the LAR was to modify limiting condition for operation for Technical Specification 3.8.1, AC [alternating current] Sources-Operating, to provide additional time to restore an inoperable offsite circuit, modify Surveillance Requirement 3.8.1.8, and modify the current licensing basis, as described in the Updated Final Safety Analysis Report, for the available maintenance feeder for the Common Station Service Transformers (CSSTs A and B). On February 26, 2014, the NRC staff transmitted an RAI by electronic mail to TVA (ADAMS Accession No. ML14056A525).

During the meeting on April 24, the senior electrical reviewer expressed concerns with TVA's proposal to have an electrical circuit for the alternate AC source available but not connected to the safety busses for up to 14 days. This timeframe is discussed in RAI No. 1, but it is not satisfactorily resolved in TVA's submitted response. The staff is concerned that the proposed amendment would deviate from the current license basis because sources would not be immediately connected to safe shutdown busses. Allowing the delayed AC sources to be unconnected for a period of 14 days, as stated in the LAR, would not meet General Design Criterion (GDC) 17. TVA agreed to discuss the issue and come up with an appropriate timeframe.

The NRC staff and TVA discussed RAI No. 4, which states:

The staff is currently reviewing the degraded voltage relay (DVR) setpoint for the shutdown boards when supplied through the normal source using CSST C and D.

Please verify that the DVR setpoint adequacy will be validated for shutdown boards

when supplied through CSST A and B using the same methodology as approved for the normal source.

TVA's submitted response to RAI 4 states:

The WBN 2 DVR setpoints for the shutdown boards is under review by NRC. TVA has requested a meeting with NRC to discuss the DVR setpoints and conformance to NRC requirements and guidance. This meeting is currently scheduled for April 24, 2014. The DVR relays are physically located on the shutdown boards, thus the DVR settings when approved by the NRC, will be valid whether CSSTs C and D or combinations of CSSTs Cor D with CSSTs A orB supplying power to the boards.

The same methodology for validating the DVR setpoints is used for the various combinations of CSSTs supplying the boards described in the LAR.

The NRC staff said that TVA's response should be updated so that it is consistent with future submittals clarifying the DVR setpoint methodology.

On Monday May 19, a clarifying call was held between the NRC staff and TVA to discuss, specifically, what information is needed to show that GDC 17 is met. The NRC staff said additional information should be submitted soon to facilitate the timeliness of the technical review.

RAI Questions 1 and 6 are related to the time delay associated with using CSST A and B as a GDC 17 source. GDC 17 requires two sources of offsite power; one immediate source and one source that can be delayed. The GDC does not define the requirement for allowable delay time in the second source. However, the GDC states that, "The safety function for each system (assuming the other system is not functioning) shall be to provide sufficient capacity and capability to assure that (1) specified acceptable fuel design limits and design conditions of the reactor coolant pressure boundary are not exceeded as a result of anticipated operational occurrences and (2) the core is cooled and containment integrity and other vital functions are maintained in the event of postulated accidents."

The LAR proposes CSST A (or CCST B) to be "available" but not connected to the shutdown busses. The staff has noted that CSST A and B have adequate capacity to support safe shutdown of the WBN units. The staff requested information on how this proposed delayed path with CSST A (or B) in 'available mode' is able to support GDC 17 requirements (1) and (2) noted above. The RAI responses in the letter dated April 21, 2014, did not provide a clear answer related to the proposed delay in the second GDC 17 source.

The April 24 meeting concluded with the staff restating that the review of the submitted RAI responses will be delayed until TVA submits additional information as clarified above.

Please direct any inquiries to me at 301-415-2048 or via e-mail at Justin. Poole@nrc.gov Justin C. Poole, Senior Project Manager Watts Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-390

Enclosure:

List of Attendees cc w/encl: Distribution via Listserv

MEETING ATTENDANCE LIST Licensee: Tennessee Valley Authority Plant: Watts Bar Nuclear Plant. Unit 1

Subject:

Request for Additional Information Related to AC Power Source License Amendment Request Date: April24, 2014 Location: U.S. Nuclear Regulatory Commission Time: 11:00 a.m. -12:00 p.m.

Headquarters, Room 0-7B4 NAME TITLE ORGANIZATION Senior Project Manager, Justin Poole NRC/NRR/DORL/WBN Watts Bar Unit 2 Project Manager, Watts Bar Siva Lingam NRC/NRR/DORL/WBN Unit 1 Jeanne Dion Project Manager NRC/NRR/DORL/WBN Gurcharan (Singh)

Senior Electrical Engineer NRC/NRR/DE/EEEB Matharu Gordon Arent Director, WBN Licensing TVA Jose R. Dubon Licensing Engineer TVA Watts Bar Unit 2, Electrical Steven Hilmes TVA and I&C Manager Enclosure

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