BVY 13-084, Revision of Technical Specification Bases Page

Revision of Technical Specification Bases Page

ML13256A093
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	09/09/2013
From:	Chappell C Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BVY 13-084
Download: ML13256A093 (4)

Text

Entergy Nuclear Operations, Inc.

'~ Entergy Vermont Yankee 320 Governor Hunt Rd Vernon, VT 05354 Tel 802 257 7711 Coley C. Chappell Licensing Manager BVY 13-084 September 9, 2013 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555

SUBJECT:

Revision of Technical Specification Bases Page Vermont Yankee Nuclear Power Station Docket No. 50-271 License No. DPR-28

REFERENCE:

Letter, USNRC to Entergy, "Vermont Yankee Nuclear Power Station -

Issuance of Amendment to Renewed Facility Operating License RE: Change to Licensing Basis Regarding Station Blackout (TAC NO. MF0422)," NVY 13-090, dated August 15, 2013

Dear Sir or Madam:

This letter provides revised a Vermont Yankee Nuclear Power Station (VY) Technical Specification (TS) Bases page. The TS Bases were revised in conjunction with an Amendment to Renewed Facility Operating License DPR-28 issued in the referenced letter.

This change, processed in accordance with our TS Bases Control Program (TS 6.7.E), was determined not to require prior NRC approval. The revised Bases page is provided in Attachment 1 for your information and for updating and inclusion with your copy of VY TS. No NRC action is required in conjunction with this submittal.

There are no new regulatory commitments being made in this submittal.

Should you have any questions concerning this submittal, please contact me at 802-451-3166.

Sincerely, CcD!

BVY 13-084 / Page 2 of 2

Attachment:

1. Revised Technical Specification Bases Page cc: Mr. William M. Dean Regional Administrator, Region 1 U.S. Nuclear Regulatory Commission 2100 Renaissance Blvd, Suite 100 King of Prussia, PA 19406-2713 Mr. Douglas V. Pickett, Project Manager Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 08C2A Washington, DC 20555 USNRC Resident Inspector Entergy Nuclear Vermont Yankee, LLC 320 Governor Hunt Rd Vernon, Vermont 05354 Mr. Christopher Recchia, Commissioner VT Department of Public Service 112 State Street - Drawer 20 Montpelier, Vermont 05620-2601

BVY 13-084 Docket No. 50-271 Attachment 1 Vermont Yankee Nuclear Power Station Revised Technical Specification Bases Page

VYNPS BASES:

3.10 AUXILIARY ELECTRIC POWER SYSTEMS A. The objective of this Specification is to assure that adequate power will be available to operate the emergency safeguards equipment.

Adequate power can be provided by any one of the following sources: an immediate access source through both startup transformers, backfeed through the main transformer, or either of the two diesel generators.

The backfeed through the main transformer is a delayed access off-site power source. The delayed access source is made available by opening the generator no load disconnect switch and establishing a feed from the 345 kV switchyard through the main generator step up transformer and unit auxiliary transformer to the 4.16 kV buses. The delayed access source is available within an hour of loss of main generator capability to assure that fuel design limits and design conditions of the reactor coolant pressure boundary are not exceeded.

Electric power can be supplied from the off-site transmission network to the on-site Emergency Safeguards Electric Power Distribution System by two independent sources, one immediate access and one delayed access, designed and located so as to minimize to the extent practicable the likelihood of their simultaneous failure under operating and postulated accident and environmental conditions. An additional on-site Station Blackout Diesel Generator and an off-site source, a 4160 V tie line to Vernon Hydroelectric Station, can supply either 4160 V emergency bus.

The on-site Station Blackout Diesel Generator is used to meet station blackout licensing requirements. The 4160 V tie line is used to meet Appendix R licensing requirements.

Off-site power is supplied to the Vermont Yankee (VY) 345 kV switchyard from the transmission network via two independent 345 kV tie lines from the Vernon 345 kV switchyard. Both 345 kV tie lines are sized to carry the entire output of Vermont Yankee. Each 345 kV tie line is protected by two diverse and redundant channels of line protection. The loss of one tie line does not affect the reliability or operability of the other. The new Vernon 345 kV switchyard is located just north of the VY 345 kV switchyard. The Vernon 345 kV switchyard is connected to the 345 kV grid by four 345 kV transmission lines utilizing a "breaker and a half" scheme. With this redundant configuration, either 345 kV tie line meets the requirements for an operable delayed access source.

In the VY 345 kV switchyard, a 400 MVA autotransformer is connected between the 345 kV north bus and the VY 115 kV bus through the K-I breaker. A second 400 MVA transformer, located in the new Vernon switchyard, connects the Vernon 345 kV switchyard to the Vernon 115 kV yard. This second autotransformer also feeds the VY 115 kV switchyard through the 115 kV K-40 tie line from the Vernon 115 kV switchyard. The two autotransformers are operated in parallel to feed the VY 115 kV bus but are physically separated and electrically independent. The loss of one autotransformer will not cause loss of the other one. The two autotransformers are the normal source of power for the 115 kV bus and the station startup transformers. They also feed the 115 kV transmission line to Chestnut Hill/Vernon Road.

The immediate access source power is provided to the 4160 buses through two startup transformers fed from the VY 115 kV switchyard through disconnect T-3. It is available within seconds following a design basis accident to assure core cooling, containment integrity and other vital functions are being maintained. The normal supply to the VY 115 kV switchyard bus is from the two paralleled, but independent, 345 kV/115 kV autotransformers described above. In the unlikely event that both autotransformers are out of service, an alternate immediate access source through the Chestnut Hill/Vernon Road line, Vernon 115 kV yard and K-40 Tie Line may be made available. Its availability is dependent on its preloading of the Chestnut Hill/Vernon Road line which must be limited by system Amendment No. 2-'&, 14, 4-5-&, BVv -0 S2, 2--3, BVY 08 060, RVY 10 924, 220

.VY 10 05, 258