ML17348B414
| ML17348B414 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 02/28/1992 |
| From: | Rajender Auluck Office of Nuclear Reactor Regulation |
| To: | Goldberg J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| IEIN-88-55, TAC-M82839, TAC-M82840, NUDOCS 9203040258 | |
| Download: ML17348B414 (5) | |
Text
~P,tt RSGIy~
P co I
OO
+>>*d ~
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555 February 28, 1992 Docket Nos.
50-250 and 50-251 Mr. J.
H. Goldberg President Nuclear Division Virginia Electric and Power Company 5000 Dominion Blvd.
Glen Allen, Virginia 23060
Dear Mr. Goldberg:
SUBJECT:
TURKEY POINT UNITS 3 AND 4 RE(UEST fOR ADDITIONAL INFORMATION ON SWING BUS TRANSFER SCHEME (TAC NOS.
M82839 AND M82840)
During our review of the Technical Specifications change request for the undervoltage relay setpoints at 480V Load Centers (Amendment Nos.
145 and 140 for Units 3 and 4, respectively),
the staff noted that transfer schemes are being utilized to power 480V Load Centers (3H and 4H) from either redundant Class 1E buses (3C, 3D, 4C, and 4D) at Turkey Point Units 3 and 4.
In addition, these swing buses (3H and 4H) could also be utilized to tie the redundant divisions (Trains A and B) together in the event an emergency diesel generator is not available.
The staff is concerned that an automatic transfer capability between redundant emergency buses could compromise the independence of redundant power sources.
Additionally, the staff is concerned that such a scheme may be vulnerable to a
single failure and fail to perform its intended emergency core cooling system (ECCS) functions (e.g., failure to transfer properly or a loss of the swing bus itself).
To illustrate the staff's concern on the vulnerability of swing bus designs, several examples are discussed below.
A single failure of the dc control power in one division at Fermi 2 prevented an automatic transfer of the swing bus to its alternate ac power source, thus resulting in a loss of the capability of all low pressure coolant injection (LPCI) pumps to perform their intended ECCS design function.
An event occurred at R.
E. Ginna where the swing safety injection pump auto transfer scheme did not function as designed during the steam generator tube rupture incident (SER/NUREG-0916).
'As a result, the licensee modified the shared SI pump transfer logic and design which incorporated a lockout design feature to prevent automatic transfer under a bus or load fault condition.
On January 28,
- 1988, H.
B. Robinson Unit 2 reported that a single failure vulnerability (loss of dc control power) and swing bus operation could result
~j in loss of two of the three safety injection pumps.
Subsequently, Information Notice No. 88-55 was issued addressing this event.
9203040258 920228 PDR,g ADOCIds; 05000250'
'" "' 'DRI,
Hr. J.
H. Goldberg February 28, 1992 In view of the fact that the Turkey Point, Units 3 and 4
FSAR contains no detailed explanation on the automatic transfer
- scheme, please provide the following information:
(2)
(3)
Describe the transfer logic of the above swing buses (3H and 4H),
including how the train is selected initially arid 'the conditions under which transfer to the other train is accomplished, and the time delays for achieving this transfer.
Explain how the swing bus transfer scheme between redundant safety trains satisfies Safety Guide 6 criteria (that is, such a design should not compromise the independence between redundant onsite power sources and should meet the single failure criterion).
Describe how this design incorporates features to prevent automatic transfer of a fault (bus or, load) to the redundant bus on a subsequent undervoltage condition and'explain whether the system is able to perform its safety function without the use of the swing bus.
This requirement affects fewer than 10 respondents and, therefore, is not subject to Office of Hanagement and Budget review under P.L.96-511.
If you have any questions, please call me at (301) 504-1471.
Sincerely, cc:
See next page DISTRIBUTION Docket File NRC 3 Local PDRs PDII-2 RF G. Lainas S. Varga H. Berkow
/s/
Rajender Auluck, Sr. Project Hanager Project Directorate II-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation R. Auluck D. Hiller OGC ACRS (10)
P.
Kang, 7/E/4 H. Sinkule, RII Document Name A:TP.RAI LAi H'
uck: kdj 92 2 ~/92 D:
II-2 HBerkow g /38/92
~I
'T E
Y f II
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 Admini strator 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, F.lorida 33102 Mr. R.
E. Grazio Director, Nuclear Licensing Florida Power and Light Company P.O.
Box 14000 Juno
- Beach, Florida 33408-0420