ML20065D493

Request for Amend TS-340 to License DPR-68,revising TS to Add Operability & SRs to Support Unit 3 480-volt Load Shed Logic Sys Being Added by Design Change

ML20065D493
Person / Time
Site:	Browns Ferry
Issue date:	03/29/1994
From:	Salas P TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20065D496	List: ML20065D493 ML20065D510
References
NUDOCS 9404070104
Download: ML20065D493 (8)

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Tennessee Vaney Autnonly. Post Othce Box 2000 Decatur, Alabama 35609 MAR 2 91994 TVA-BFN-TS-340 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555

Gentlemen

In the Matter of ) Docket No. 50-296 Tennessee Valley Authority )

BROWNS FERRY NUCLEAR PLANT (BFN) - UNIT 3 - TVA TECHNICAL SPECIFICATION (TS) NO. 340 - UNIT 3 EMERGENCY DIESEL l GENERATOR LOAD SHEDDING In accordance with the provisions of 10 CFR 50.4 and 50.90, TVA is submitting a request for an amendment (TS-340) to license DPR-68 to change the Technical Specifications for Unit 3. The proposed change adds operability and surveillance requirements to support the Unit 3 480-volt load shed logic system being added by a design change.

TVA has determined that there are no significant hazards considerations associated with the proposed change and that the change is exempt from environmental review pursuant to 10 CFR 51.22 (c) (9) . The BFN Plant Operations Review Committee and the BFN Nuclear Safety Review Board have reviewed this proposed change and determined that operation of BFN Unit 3 in accordance with the proposed change will not endanger the l health and safety of the public. Additionally, in.accordance with 10 CFR 50. 91(b) (1) , TVA is sending a copy of this letter and enclosures to the Alabama State Department of Public Health.

Enclosure 1 to this letter provides the description and evaluation of the proposed change. This includes TVA's determination that the proposed change does not involve a 9404070104 DR 940329 ADOCK 05000296 (

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s U.S. Nuclear Regulatory Commission Page 2 MAR 2 91994 i

significant hazards consideration and is exempt from environmental review. Enclosure 2 contains copies of the appropriate Unit 3 TS pages marked-up to-show the proposed change. Enclosure 3 forwards the revised TS pages for Unit 3 which incorporate.the proposed change.

In TVA i s letter to NRC dated December 23, 1993, TVA provided need dates for NRC approva? Of* those.TS changes required to support Unit 3 restart. Coi ' stent with the information provided in that letter, TVA-ts vuests NRC approval of this amendment by April 7, 1995.

As previously stated, this TS change adds operability and surveillance requirements that support a modification to BFN.

This TS change, will make the Unit 3 TSs consistent with Units 1 and 2. It is TVA's position that the preferred method for maintaining operability of the 480-volt load shedding logic' system is through the TSs; however, if this f change is not approved by restart of Unit-3, TVA will impose additional' administrative requirements on the 480-volt load

! shedding logic system that will control the operability of l the equipment.

TVA will inform NRC of any significant changes to the need date through BFN's regular communications with the Staff's -

Project Managers for BFN.

TVA requests that the ravised TS be made effective within 30 l

days of NRC approval. If you have any questions about this change, please telepho.ne me at (205) 729-2636.

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l Pedro Salas Manager of Site Licensing l

l Subscribed and sworn be ore me n this DHh day of GAL 1994.

h R. bDcdcn Notary Public

!My Commission Expires d donD,p.rcoyM4 l

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U.S. Nuclear Regulatory Commission Page 3

, MAR 2 91994 i

Enclosures cc.(Enclosures):,

' 'American Nuclear Insurers ~i Town Center, Suite 300S l 29 South. Main Street- ,

West Hartford, Connecticut 06107-2445 Mr. W. D.-Arndt General Electric' Company ,

735 Broad Street

• Suite 804,' James Building Chattanooga, Tennessee 37402 Mr. Johnny Black, Chairman Limestone County Commission 310 Washington Street Athens, Alabama 35611-Mr. R. V. Crlenjak, Project Chief

, U.S. Nuclear. Regulatory Commission, Region II 101 Marietta Street, NW, Suite 2900 l Atlanta, Georgia 30323 NRC Resident Inspector Browns' Ferry Nuclear Plant.

Route 12, Box 637 Athens, Alabama 35611 Mr. D. C. Trimble,. Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. Joseph F. Williams, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Dr. Donald E. Williamson State Health Officer i State Department of Public Health l State Office Building Montgomery, Alabama 36194 j

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ENCLOSURE 1 i TENNESSEE VALLEY AUTHORITY  :

BROWNS FERRY NUCLEAR PLANT (BFN) l UNIT 3 PROPOSED TECHNICAL SPECIFICATION (TS) CHANGE TS-340 DESCRIPTION AND EVALUATION OF THE PROPOSED CHANGE I l

I. DESCRIPTION OF THE PROPOSED CHANGE BFN Unit 3 TSs are-being amended to add a limiting )

condition for operation and a surveillance requirement for I a Unit 3 480-volt load shedding logic system being added by )

a design change. A 480-volt load shedding logic is being added to the Unit 3 Auxiliary Electrical system to ensure ,

that the maximum capacity of the Unit 3 Emergency Diesel l Generators (EDG) is not exceeded during a postulated loss l of offsite power concurrent with a design basis accident condition.

BFN Unit 3 has four EDGs that supply backup power to the Unit 3 Auxiliary Electrical system. The system mainly ,

consists of four 4kV shutdown boards, two 480-volt shutdown I boards, five motor operated. valve boards,.four motor j generator sets, two diesel auxiliary boards, and a Standby 1 Gas Treatment System board. l This proposed TS change is consistent with the approved 1 Units 1 and 2 TSs.

The specifics of this proposed change are as follows:

1. Revise 3.9.A.5. to read as follows:

5. Loaic Systems

a. Accident signal logic system is OPERABLE.

b. 480-volt losd shedding logic system is l OPERABLE.  ;

2. Adds surveillance requirement "b." to the Auxiliary Electrical System section of TSs, paragraph 4.9.A.3.

b. Once every 18 months, the condition under which '

the 480-volt load shedding logic system is required shall be simulated to demonstrate that the load shedding logic system would initiate load shedding signals on the diesel' auxiliary boards, RMOV boards, and the 480-volt shutdown boards.

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. I II. REASON FOR THE PROPOSED CRANGE This proposed TS change adds a limiting condition for operation (LCO) and a surveillance requirement for the Unit a 3 480-volt load shedding logic system that is being added by a design change being implemented under 10 CFR 50.59.

The Unit 3 EDGs are now being utilized to support Unit 2 operation and are lightly loaded. Therefore, Unit 3 480- i volt load shedding logic is not required until restart of j Unit 3. )

Analysis performed as part of the design baseline verification effort for Unit 3 restart has shown that Unit 3 EDGs (3A and 3C) could be overloaded during multiunit operation with a loss of offsite power concurrent with a Unit 3 design basis accident. Consequently, prior to the 1 1

restart of Unit 3, TVA will implement a design change that automatically strips the 480-volt loads not required for short-term post accident mitigation from the safety-related auxiliary electrical systems.

BFN Units 1 and 2 have four EDGs that supply power to the Unit 1 and 2 4kV shutdown boards upon loss of offsite power. Because Units 1 and 2 share four EDGs, there has always been a 480-volt load shedding logic feature for these units from the time of initial licensing.

In TVA's letter to NRC dated December 23, 1993, TVA

> provided need dates for NRC approval of-those TS changes required to support Unit 3 restart. Consistent with the information provided in that letter, TVA requests NRC approval of this amendment by April 7, 1995.

As previously stated, this TS change adds operability and surveillance requirements that support a modification to BFN. This TS change, will make the Unit 3 TSs consistent with Units 1 and 2. It is TVA's position that the preferred method for maintaining operability of the 480-volt load shedding logic system is through the TSs; however, if this change is not approved by restart of Unit 3, TVA will impose additional administrative requirements on the 480-volt load shedding logic system that will control the operability of the equipment.

TVA will inform NRC of any significant changes to the need date through BFN's regular communications with the Staff's Project Managers for BFN.

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4 III. BAFETY ANALYSIS TVA is implementing a design change that upon loss of offsite power, concurrent with a Unit 3 accident signal, sheds 480-volt loads not required for short-term post accident mitigation from the Unit 3 safety-related auxiliary electrical systems. Through the implementation of this design change, the maximum capacity of the EDGs will not be exceeded during a design basis accident.

The 480-volt load shedding logic system will trip 480-volt loads not required for short term accident mitigation (e.g., Main Steam system, Raw Service Water system, CO 2 Storage, Fire Protection and Purging system) from 480-volt Shutdown Boards 3A and 3B, Diesel Auxiliary Boards 3EA and 3EB, Reactor Motor Operated (RMOV) Valve Boards 3A and 3B, and the RMOV Board 3C feeder breaker.

The load shedding logic system is designed to operate on a divisional basis. A Division I signal initiates load shedding signal on the non-critical loads associated with 480-volt Shutdown Board 3A, RMOV Board 3A, and Diesel Auxiliary Board 3EA. A Division II signal initiates load shedding on 480-volt Shutdown Board 3B, RMOV board 3B, and the Diesel Auxiliary Board 3EB.

The TS is being changed to specify operability and surveillance requirements for equipment required for safe shutdown of Unit 3. The LCO prescribes a minimum level of performance for the 480-volt load shedding logic. The LCO requires that the load shedding be operable prior to start up from a cold condition. Furthermore, the addition of a I

surveillance requirement ensures the minimum level of performance is maintained. Testing of the 480-volt load f shedding logic on an interval of 18 months is consistent j with BWR/4 (NUREG-1433) Standard Technical Specifications.

The objective of the Auxiliary Electrical system is to assure an adequate supply of electrical power for operation I

of those systems required for safe shutdown of Unit 3.

Implementation of a design change that sheds non-essential loads from the Unit 3 Auxiliary Electrical system assures that adequate power can be supplied by the EDGs under postulated accident conditions. Therefore, revising these TSs to include an LCO and surveillance requirement for the load shedding logic provides assurance that this objective is met. l IV. NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION TVA has concluded that operation of Browns Ferry Nuclear Plant Unit 3 in accordance with the proposed change to the technical specifications does not involve a significant El-3

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hazards consideration. TVA's conclusion is based on its i evaluation, in accordance with 10 CFR 50.91(a) (1) , of three standards set forth in 10 CFR 50.92(C). TVA's conclusion is based on the following:

A. The Droposed amendment does not involve a significant j increase in the probability or consecuences of an i accident previously evaluated. j This proposed change establishes a surveillance i testing requirement and limiting condit.an for  !

I operation for the Unit 3 480-volt load shedding logic system. This Technical Specification change will not  ;

introduce any new failure mode and will not alter any assumptions previously made in evaluating the consequences of an accident. Accordingly, this change j does not affect any design limiting safety system i settings or operating parameters. Furthermore, the change does not modify or add any accident initiating events or parameters. Therefore, these proposed l changes do not involve an increase in the probability ,

or consequences of an accident previously evaluated. l l

B. The Droposed amendment does not create the possibility of a new or different kind of accident from any accident oreviously evaluated.

This proposed change establishes a limiting condition l for operation and a surveillance requirement for the Unit 3 480-volt load shedding logic system. The addition of a limiting condition for operation and surveillance requirement will not adversely affect the operation of Unit 3 or the manner in which it is operated. Furthermore, the change does not create a failure mode that can lead to an accident of a different type than previously evaluated. Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident l previously evaluated.

l C. The proposed amendment does not involve a sicnificant I reduction in a marcin of safety.

The addition of a limiting condition for operation and surveillance requirement will not reduce the margin of i safety. The testing of the 480-volt load shedding l logic on an 18-month interval is consistent with BWR/4 (NUREG-1433) Standard Technical Specifications. These are based on the guidance set forth in NRC Regulatory ,

Guide 1.108, " Periodic Testing of Diesel Generator l Units Used as Onsite Electric Power Systems at Nuclear Power Plants." The addition of a limiting condition i for operation establishes a minimum acceptable level of performance for the 480-volt load shedding logic El-4

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system. Thus, the ability of the Emergency Diesel Generators to supply power during a loss of offsite. ,

power coincident with a design basis accident is assured.

Furthermore, no reductions in the requirements or setpoints of the equipment supplied by the Emergency Diesel Generators are_made which could result in a reduction in the margin of safety. Therefore, this proposed change does not involve a reduction in the margin of safety.

V. ENVIRONMENTAL IMPACT CONSIDERATION The proposed change does not involve a significant hazards consideration, a significant change in the types of or significant increase in the amounts of any effluent that may be released offsite, or a significant increase in individual or cumulative occupational radiation exposure.

Therefore, the proposed change meets the eligibility ,

criteria for categorical exclusion set forth in 10 CFR l

51. 22 (c) (9 ) Therefore, pursuant to 10 CFR 51.22(b), an environmental assessment of the proposed change'is not l required.

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