ML13276A049
| ML13276A049 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 09/30/2013 |
| From: | James Shea Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML13276A049 (4) | |
Text
Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 September 30, 2013 10 CFR 50.4 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Sequoyah Nuclear Plant, Units 1 and 2 Facility Operating License Nos. DPR-77 and DPR-79 NRC Docket Nos. 50-327 and 50-328
Subject:
Third Status Update of Planned Actions to Facilitate Maintenance of 6.9 Kilovolt and 480 Volt Shutdown Boards at Sequoyah Nuclear Plant, Units I and 2
References:
- 1. Letter from TVA to NRC, "Planned Actions to Facilitate Planned Maintenance of 6.9 Kilovolt and 480 Volt Shutdown Boards at Sequoyah Nuclear Plant, Units 1 and 2," dated July 17, 2012 [ML12202A011]
- 2. Letter from TVA to NRC, "Status Update of Planned Actions to Facilitate Maintenance of 6.9 Kilovolt and 480 Volt Shutdown Boards at Sequoyah Nuclear Plant, Units 1 and 2," dated October 26, 2012 [ML12307A111]
- 3. Letter from TVA to NRC, "Second Status Update of Planned Actions to Facilitate Maintenance of 6.9 Kilovolt and 480 Volt Shutdown Boards at Sequoyah Nuclear Plant, Units 1 and 2," dated March 28, 2013
[ML13092A103]
In the Reference 1 letter, Tennessee Valley Authority (TVA) committed to provide an update to the Nuclear Regulatory Commission (NRC) of the status of the efforts to permit the scheduling of preventive maintenance on the Sequoyah Nuclear Plant (SQN) 6.9 Kilovolt (kV) and 480 Volt (V) Shutdown Boards for Units 1 and 2 with one unit in Mode 5 or 6 or defueled and the other unit in Mode 1, 2, 3, or 4. The update was to include a projection of the submittal of the SQN Improved Technical Specifications (ITS) application and the status of associated modification design efforts. TVA provided the status update on October 26, 2012 (Reference 2).
The Reference 2 and 3 letters included similar commitments and provided corresponding status updates of the planned SQN ITS application and associated modifications, and submittal of an Ultimate Heat Sink (UHS) license amendment request (LAR) needed to support the shutdown board preventive maintenance effort.
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U.S. Nuclear Regulatory Commission Page 2 September 30, 2013 The Reference 3 letter included a commitment to provide, by September 30, 2013, an update of the information previously provided. This letter satisfies the Reference 3 update commitment.
TVA's development of the SQN ITS conversion application is nearly completed, with projected submittal to the NRC by the end of October 2013. The planned ITS application includes provisions in Section 3.8.1, "AC Sources - Operating," and Section 3.8.9, "Distribution Systems -
Operating," such that, with the associated (operating) unit in Mode 1, 2, 3, or 4 and the opposite (shutdown) unit in Mode 5 or 6 or defueled, one of the shutdown unit's 6.9 kV Shutdown Boards and the associated normally connected 480 V Shutdown Boards may be taken out of service for up to seven days. The proposed ITS Completion Time of seven days to restore operability of the affected shutdown boards is sufficient to facilitate planned preventive maintenance on the individual shutdown boards provided that compliance with the applicable ITS Conditions and Required Actions does not impose more restrictive Completion Time(s). In order to avoid entry into Conditions with more restrictive Completion Times, TVA has determined that additional operating limits on the Ultimate Heat Sink (UHS) and Essential Raw Cooling Water (ERCW) system are required, as well as permanent modifications to the SQN Auxiliary Control Air (ACA) system and 125 V Vital Direct Current (DC) system. The ITS application is being developed to allow for NRC review and approval, and subsequent plant implementation while completing the design changes for the seven-day Completion Time.
Implementation of the additional operating limits for the UHS and ERCW system will require a change to current Technical Specification (CTS) Section 3.7.5, "Ultimate Heat Sink." TVA is in the final stages of developing a LAR that proposes a relaxation of the requirements of the ERCW supply header water temperature of CTS 3.7.5 with one unit shutdown, and will be applicable to both SQN units. Because the UHS LAR supports proposed changes integral to the ITS application, the UHS LAR is scheduled to be submitted before or concurrent with the ITS application.
The other design and licensing basis changes needed to support shutdown board preventive maintenance, including the ACA and Vital DC modifications and various associated subordinate facility changes, are intended to be implemented under the provisions of Title 10 of the Code of Federal Regulations (10 CFR) 50.59 or as part of the ITS conversion project, as previously described. The two major modification projects supporting the shutdown board preventive maintenance effort (i.e., the ACA and Vital DC modifications) have been budgeted to start in Fiscal Year 2014.
TVA will provide a further update no later than March 28, 2014 on the status of the SQN ITS conversion application and UHS LAR submittal and supporting design activities associated with implementation of periodic shutdown board preventive maintenance at SQN.
U.S. Nuclear Regulatory Commission Page 3 September 30, 2013 There is one regulatory commitment contained in this letter as described in the enclosure.
Please address any questions regarding this letter to Clyde Mackaman at (423) 751-2834.
Respectfully, President, Nuclear Licensing Enclosure List of Commitments cc (Enclosure):
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Sequoyah Nuclear Plant
Enclosure Sequoyah Nuclear Plant, Units I and 2 List of Commitments Update Letter Regarding Implementation of Shutdown Board Preventive Maintenance Tennessee Valley Authority will provide an update letter on the status of the planned Sequoyah Nuclear Plant (SQN) Improved Technical Specification (ITS) conversion application and Ultimate Heat Sink (UHS) license amendment request (LAR) submittal and supporting design activities associated with implementation of periodic shutdown board preventive maintenance at SQN. This letter will provide an update of the information previously provided in the September 30, 2013 letter regarding this subject, and will be submitted no later than March 28, 2014.