BVY 08-081, Submittal of Revision of Technical Specification Bases Page 29

Submittal of Revision of Technical Specification Bases Page 29

ML083260572
Person / Time
Site:	Vermont Yankee
Issue date:	11/17/2008
From:	Michael Colomb Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BVY 08-081
Download: ML083260572 (4)

Text

m Entergy Nuclear Operations, Inc.

Vermont Yankee P.O. Box 0250 En 320 Governor Hunt Road Vernon, VT 05354 Tel 802 257 7711 November 17, 2008 BVY 08-081 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)

Revision of Technical Specification Bases Page 29

Dear Sir or Madam,

This letter provides revised Technical Specification (TS) Bases page. TS Bases page 29 was revised to recognize an additional condition under which the APRMs may be bypassed provided the minimum number of operable channels is maintained. The additional information is consistent with Vermont Yankee's licensing basis.

This change to the TS Bases was processed in accordance with the TS Bases Control Program specified in TS 6.7.E and has been determined to not require a license amendment in accordance with 10CFR50.59. Therefore, prior NRC approval is not required.

A revised TS Bases page is attached for your records. No NRC action is requested on this submittal.

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

If you have any questions concerning this submittal, please contact Mr. David J. Mannai at (802) 451-3304.

Sincerely, Michael J\.,oomUb Site Vice President Vermont Yankee Nuclear Power Station

Attachment:

Revised Technical Specification Bases Page cc list (next page)

BVY 08-081 Docket 50-271 Page 2 of 2 cc: Mr. Samuel J. Collins, Region 1 Administrator U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406-1415 Mr. James S. Kim, Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 USNRC Resident Inspector Vermont Yankee Nuclear Power Station 320 Governor Hunt Road P.O. Box 157 Vernon, VT 05354 Mr. David O'Brien, Commissioner VT Department of Public Service 112 State Street, Drawer 20 Montpelier, VT 05620-2601

BVY 08-081 Docket No. 50-271 Attachment 1 Vermont Yankee Nuclear Power Station Revised Technical Specification Bases Page

VYNPS BASES:

3.1 Reactor Protection System The reactor protection system automatically initiates a reactor scram to:

1. preserve the integrity of the fuel barrier;

2. preserve the integrity of the primary system barrier; and

3. minimize the energy which must be absorbed, and prevent criticality following a loss of coolant accident.

This specification provides the limiting conditions for operation necessary to preserve the ability *of the system to tolerate single failures and still perform its intended function even during periods when instrument channels may be out of service because of maintenance, testing, or calibration. The basis for the allowable out-of-service times is provided in GE Topical Report NEDC-308512-A, "Technical Specification Improvement Analysis for BWR Reactor Protection System," March 1988.

The reactor protection system is of the dual channel type. The system is made up of two independent logic channels, each having three subsystems of tripping devices. One of the three subsystems has inputs from the manual scram push buttons and the reactor mode switch. Each of the two remaining subsystems has an input from at least one independent sensor monitoring each of the critical parameters. The outputs of these subsystems are combined in a 1 out 'of 2 logic; i.e., an input signal on either one or both of the subsystems.will cause a trip system trip. The outputs of the trip systems are arranged so that a t-rip on both logic channels is required to produce a reactor scram.

The required conditions when the minimum instrument logic conditions are not met are chosen so as to bring station operation promptly to such a condition that the particular protection instrument is not required; or the station is placed in the protection or safe condition that the instrument initiates. This is accomplished in a normal manner without subjecting the plant to abnormal operating conditions.

When the minimum requirements for the number of operable or operating trip system and instrumentation channels are satisfied, the effectiveness of the protection system is preserved; i.e., the system can tolerate a single failure and still perform its intended function of scramming the reactor.

Three APRM instrument channels are provided for each protection trip system to provide ,for high neutron flux protection. APRM's A and E operate contacts in a trip subsystem, and APRM's C an E operate contacts in the other trip subsystem. APRM's B, D, and F are arranged similarly in the other protection trip system. Each protection trip system has one more APRM than is necessary to meet the minimum number required. This allows the bypassing of one APRM per protection trip system for maintenance, testing, calibration, or to minimize single failure vulnerabilities associated with shared LPRMs, while maintaining the minimum number of channels required for inputs to each trip system. Operating with two APRMs bypassed meets all design and technical specification requirements.

Additional IRM channels have also been provided to allow bypassing of one such channel. For a description of the Neutron Monitoring Systems, see FSAR Section 7.5.

The bases for the scram settings for the IRM, APRM, high reactor pressure, reactor low water level, turbine control valve fast closure, and turbine stop valve closure are discussed in Specification 2.1.

Amendment No. 24, -+-4, 44-4, B, BVY 08-081 29