ML17340A631
| ML17340A631 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 01/14/1981 |
| From: | Robert E. Uhrig FLORIDA POWER & LIGHT CO. |
| To: | Novak T Office of Nuclear Reactor Regulation |
| References | |
| L-81-16, NUDOCS 8101220150 | |
| Download: ML17340A631 (6) | |
Text
REGULATORY NFORMATION 'DISTRIBUTION SYSTEM (RIDS)
CCESSION NBR:8101220150 DOC,DATE: 81/01/14 NOTARIZcD:
NO FACIL:50 250 Turkey Point Planti Unit 3i Florida Power and Light C
050002 0
50-251 Turkey Point Plant~ Unit 4g Florida Power -and Light C
050 AUTH'YNAME AUTHOR AFFILIATION UHRIGqR ~ E ~
Flor ida Power 8 Light Co ~
REC IP ~ NAME RECIPIENT AFFILIATION NOYAKpT AM, Assistant Director-for Operating Reactors
SUBJECT:
= Submits info re proposed undervoltage protection sys design mod~in response to NRC 800818 ltd Two GE Type IAV undervoltage re'lays will be install'ed on each 4160V bus>
Proposed Tech Specs will be subm.itted upon completion
~
DISTRIBUTION CODE:
A01SS COPIES RECEIVED:LTR ENCL SI E ~
TITLE: Onsite Emergency Power Systems NOTES:.
RECIPIENT ID CODE/NAME ACTION:
VARGA g S ~
P4 INTERNAL': AEOD l8C SYS BR 09 MPA 18 OELD 17 BR 12'EG FILE 01 COPIES LTTR ENCL=
RECIPIENT ID CODE/NAME GEN ISSUES BR13 ILE
'6'RC PDR 02'OP EX EVAL BR11 POWER SYS BR 14 COPIES LtTTR ENCL EXTERNALS ACRS NSIC 16 05 16 1
1 LPDR 03 TOTAL NUMBER OF COPIES REQUIRED:
LTTR 37 ENCL
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'FLORIDA POWER 4 LIGHTCOMPANY January 14, 1981 L-81-16 Office of Nuclear Reactor Regulation Attention:
Mr. Thomas M. Novak, Assistant Director for Operating Reactors, Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.
C.
20555
Dear Mr. Novak:
Re:
Turkey Point Units 3 5 4 Docket No. 50-250, 50-251 ADEQUACY OF STATION DISTRIBUTION SYSTEM VOL'TAGES In response to your letter dated August 18, 1980 concerning the above
- subject, we have prepared the following information to further describe the undervoltage protection system design modification which will be proposed for Turkey Point Units 3
8 4.
This design, which is not yet finalized, will provide undervoltage protection at the 4160V and 480V levels.
In addition to the present loss-of-voltage relaying on the 4160V busses (described in FPL letter to NRC dated November 9, 1980),
two General Electric Type IAV undervoltage relays will be installed on each 4160V bus.
Operation of these relays is expected to be similar to'the existing loss-of-voltage relays.
The voltage setpoints will be chosen such that the relays begin to actuate when bus voltage decreases below that required to safely operate the running equip-ment.
These relays have an inverse-time characteristic which allows faster actuation with decreasing voltage.
No additional time delay will be used.
Two ITE Type 27H instantaneous undervoltage relays will be installed on each 480V Load Ceriter.
Actuation of both relays on a Load Center coincident with a Safety Injection Signal wi 11 initiate, after a
fixed time of delay, the diesel starting sequence and di:sconnection
]5 of offsite power for the associated train.
Setpoints for these S
relays will be chosen such that they actuate when: bus voltage de-creases below that required to safely start all s'afety loads.
The 3 0 fixed time delay will be chosen based on the acceleration line of 'the safety loads in order to prevent spurious trips and allow for proper safety equipment operation.
8y0 XSR0 PEOPLE... SERVING PEOPLE
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Mr. Thomas M. Novak Page Two Spurious actuation of a single undervoltage relay '(either on the 4160V or 480V busses) will not cause a trip of the offsite power sources.
A failure of a single relay to detect an undervoltage condition will not result in less
-than the minimum safety equipment havinq sufficient
. voltage to start and run.
Thus, the single failure criteria of IEEE 279-1971 is met.
The proposed undervoltage relays will be made inoperable once the busses are energized by onsite power.
Closing of the diesel genera-tor breaker on the 4KV-bus will disable the undervoltage relays.
A proposal for Technical Specification changes concernino the proposed design.modification.wi 11 be provided when the design is completed and the voltage setpoints are determined.
Very truly yours, Robert E. Uhri g Vice President Advanced Systems 5 Technology REU/PLP/bc cc:
J.
P. O'Reilly, Region II Harold F. Reis, Esquire
0 il 4