ML17349A556

Advises That Interlocks Provided to Prevent Paralleling Both Trains Together,Breakers Coordinated to Provide Selective Tripping for Overcurrent Protection & Blocking Transfer in Case of Swing Bus Fault,Per Util

ML17349A556
Person / Time
Site:	Turkey Point
Issue date:	12/07/1992
From:	Raghavan L Office of Nuclear Reactor Regulation
To:	Goldberg J FLORIDA POWER & LIGHT CO.
References
TAC-M82839, TAC-M82840, NUDOCS 9212220391
Download: ML17349A556 (5)

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555 December 7, 1992 Docket Nos.:

50-250 and 50-251 Mr. J.

H. Goldberg President Nuclear Division Florida Power and Light Company P.O.

Box 14000 Juno

Beach, Florida 33408-0420

SUBJECT:

TURKEY POINT UNITS 3 AND 4 - EVALUATION OF SWING BUS TRANSFER SCHEME (TAC NOS.

M82839 AND M82840)

Under the Emergency Power System Enhancement

Project, you have installed two new safety-related 480-volt load centers at each unit.

These load centers can be powered (i.e.,

swing bus) from either train A or B of the emergency power system via an automatic bus transfer scheme.

By letter dated May 5,

1992, you provided a response to our request for additional information on transfer logic and design features of the swing bus to assure that the redundant power sources remain independent and no single failure vulnerability exists with its transfer scheme when supplying the swing bus.

We have reviewed your response and find that interlocks have been provided to prevent paralleling both trains together, the breakers have been coordinated to provide selective tripping for overcurrent protection and blocking the transfer in case of a swing bus fault, and each power supply is routed in separate dedicated raceways to preclude failure of one power supply (ac and dc) from affecting the other.

In addition, to demonstrate that the single failure of critical components of the transfer scheme does not affect redundant trains or the ability to perform safe shutdown function, you performed a Circuit and/or Component Failure Effects Analysis (C/CFEA).

The results of the C/CFEA have identified no single failure-related problems.

9212220391 921207 PDR ADOCK 05000250 P

PDR

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F" Hr. J.

H. Goldberg December 7, 1 992 Based on our review of your submittal, we concur with you that there is a

reasonabl e assurance for the independence of redundant power sources when supplying the swing bus

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This completes our effort on TAC Nos. H82839 and H82840 Sincerely, (Original Signed By) cc:

C ~ Berl inger P.

Kang Distri buti on

=Docket F.i.l e NRC 8 Local PDRs PD II-2 Reading File S. Varga G ~ Lai nas H. Berkow E. Tan a L ~ Raghavan OGC ACRS (10)

H ~ Si nkul e, RII cc:

Plant Service list L ~ Raghavan, Project Hanager Project Directorate II-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation 0FFIGE ~4PDI 1-2 PN:PDI IQ D PO HAHE ~ d. Hiller L. Raghd '

rkow DATE 12/5/92 12/g /92 2/g/92

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Mr. J.

H. Goldberg Florida Power and Light Company Turkey Point Plant CC:

Harold F. Reis, Esquire Newman and Holtzinger, P.C.

1615 L Street, N.W.

Washington, DC 20036 Jack Shreve, Public Counsel Office of the Public Counsel c/o The Florida Legislature 111 West Madison Avenue, Room 812 Tallahassee, Florida 32399-1400 John T. Butler, Esquire

Steel, Hector and Davis 4000 Southeast Financial Center Miami, Florida 33131-2398 Mr. Thomas F. Plunkett, Site Vice President Turkey Point Nuclear Plant Florida Power and Light Company P.O.

Box 029100 Miami, Florida 33102 Joaquin Avino County Manager of Metropolitan Dade County 111 NW 1st Street, 29th Floor Miami, Florida 33128 Senior Resident Inspector Turkey Point Nuclear Generating Station U.S. Nuclear Regulatory Commission P.O.

Box 1448 Homestead, Florida 33090 Mr. Jacob Daniel Nash Office of Radiation Control Department of Health and Rehabilitative Services 1317 Winewood Blvd.

Tallahassee, Florida 32399-0700 Mr. Robert G. Nave, Director Emergency Management Department of Community Affairs 2740 Centerview Drive Tallahassee, Florida 32399-2100 Administrator Department of Environmental Regulation Power Plant Siting Section State of Florida 2600 Blair Stone Road Tallahassee, Florida 32301 Regional Administrator, Region II U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W. Suite 2900 Atlanta, Georgia 30323 Attorney General Department of Legal Affairs The Capitol Tallahassee, Florida 32304 Plant Manager Turkey Point Nuclear Plant Florida Power and Light Company P.O.

Box 029100 Miami, Florida 33102 Mr. R.

E. Grazio Director, Nuclear Licensing Florida Power and Light Company P.O.

Box 14000 Juno

Beach, Florida 33408-0420