ML20237E965
| ML20237E965 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 12/18/1987 |
| From: | GENERAL PUBLIC UTILITIES CORP. |
| To: | |
| Shared Package | |
| ML20237E952 | List: |
| References | |
| NUDOCS 8712290281 | |
| Download: ML20237E965 (3) | |
Text
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3.7 AUXILIARY ELECTRICAL POWER 4
Applicability:
Applies to the operating status of the auxiliary j
electrical power supply.
Objective:
To assure.the operability of the auxiliary electrical power supply.
Specification:
A.
The reactor shall not be made critical unless all of the following requirements are satisfied:
1.
The following buses or panels energized.
a.
4160 volt buses IC and 10 in the turbine building switchgear room.
b.
460 volt buses lA2, 182, lA21, 1821. vital MCC 1A2 and 182 in the reactor building i
switchgear room:
lA3 and 183 at the intake structure; 1A21A, 1821A, 1A218, and 1821B and vital MCC 1AB2 on 23'6" elevation in the reactor building; 1A24 and 1824 at the stack.
.c.
208/120 volt panels 3, 4, 4A, 4B, 4C and VACP-1 in the reactor building switchgear room.
d.
120 volt protection panel 1 and 2 in the cable room.
e.
125 volt DC distribution centers C and B, and panel D, Panel DC-F, isolation valve motor control center DC-1 and 125V DC motor control center DC-2.
f.
24 volt D.C. power panels A and B in the cable room.
2.
One 230 KV line is fully operational and switch gear and both startup transformers are energized to carry power to the station 4160 voit AC buses and carry power to or away from the plant.
3.
An additional source of power consisting of one-of the following is in service connected to feed the appropriate plant 4160 V bus or buses:
a.
A second 230 KV line fully operational.
b.
One 34.5 KV line fully operational.
4.
The station batteries B and C are available for normal service and a battery charger is in service for each battery.
5.
Bus tie breakers ED and EC are in the open position.
B.
The reactor shall be placed in the cold shutdown position if the availability of power falls below that required by Specification A above, except that 1.
The reactor may remain in operation for a period
'8712290281 871218 3.7-1 Amendment No.: 44, 55, 80 PDR ADOCK 050 29
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not to exceed 7 days in any 30 day period if a startup transformer is out of service.
None of
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the engineered safety feature equipment fed by l
the remaining transformer may be.out of service.
2.
The reactor may remain in operation for a period not to exceed 7 days if 125 VDC Motor Control Center DC-2 is out of service, provided the requirements of Specification 3.8 are met.
C. -
Standby Diesel Generators 1.
The reactor shall not be made critical unless -
both diesel generators are operable and capable of feeding their designated 4160 volt buses.
2.
If one diesel generator becomes inoperable during power operation, repairs shall be initiated immediately and the other_ diesel shall be operated at least one hour every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at greater than 20% rated power until repairs are completed. The reactor may remain in operation for a period not to exceed 7 days in any 30-day period if a diesel generator is out of service.
During the repair period none of the engineered safety features normally fed by the operational diesel generator may be out of service or the reactor shall be placed in the cold shutdown condition.
3.
If both diesel generators become inoperable during power operation, the reactor shall be placed in the cold shutdown condition.
4.
For the diesel generators to be considered operable there shall be a minimum of 14,000 gallons of diesel fuel in the standby diesel generator fuel tank.
Bases:
The general objective is to assure an adequate supply of power with at least one active and one standby source of power available for operation of equipment required for a safe plant shutdown, to maintain the plant in a safe shutdown condition and to ' operate the required engineered safety feature equipment following an accident.
AC power for shutdown and operation of engineered safety feature equipment can be provided by any of four active (two 230 KV and two 34.5 KV lines) and either of two standby (two diesel generators) sources of power.
Normally all six sources are available. However, to provide for maintenance and repair of equipment and still have redundancy of power sources the requirement of one active and one standby source of power was OYSTER CREEK 3.7-2 Amendment No.: 44, 55, 99
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established. The plant's main generator is not given credit as a source since it is not available during shutdown.
The plant 125V DC power is normally supplied by two batteries, each with two associated full capacity chargers.
One charger on each battery is in service at all times with the second charger available in the event of charger failure. These chargers are active sources and supply the normal 125V DC requirements with the batteries and standby sources.
(1)
In applying the minimum requirement of one active and one standby source of AC power, since both 230 KV lines are on the same set of towers, either one or both 230 KV lines are considered as a single active source.
The probability analysis in Appendix "L" of the FDSAR was based on one diesel and shows that even with only one diesel the probability of requiring engineered safety features at the same time as the second diesel fails is quite small.
This analysis used information l
on peaking diesels when synchronization was required which is not l
the case for Oyster Creek. Also the daily test of the second diesel when one is temporarily out of service tends to improve the reliability as does the fact that synchronization is not required.
As indicated in Amendment 18 to the Licensing Application, there are numerous sources of diesel fuel which can be obtained within 6 to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and the heating boiler fuel in a 75,000 gallon tank on the site could also be used. As indicated in Amendment 32 of the Licensing Application and including the Security System loads, the load requirment for the loss of offsite power would require 12,410 gallons for a three day supply.
For the case of loss of offsite i
power plus loss-of-coolant plus bus failure 9790 gallons would be required for a three day supply.
In the case of loss of offsite power plus loss-of-coolant with both diesel generators starting the load requirements (all equipment operating) shown there would not be three days' supply.
However, not all of this load is required for three days and, after evaluation of the conditions, loads not required on the diesel will be curtailed.
It is reasonable to expect that within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> conditions can be evaluated and the following loads curtailed:
- 1. One Core Spray Pump
- 2. One Core Spray Booster Pump
- 3. One Control Rod Drive Pump
- 4. One Containment Spray Pump
- 5. One Emergency Service Water Pump With these pieces of equipment taken off at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> after the incident it would require a total consumption of 12,840 gallons for a three day supply.
Therefore, a minimum technical specification requirement of 14,000 gallons of diesel fuel in the standby diesel generator fuel tank will exceed the engineered safety features i
operational requirement after an accident by approximately 9%.
References:
(1)
Letter, Ivan R. Finfrock, Jr. to the Director of Nuclear Reactor l
Regulation dated April 14, 1978.
l 0YSTER CREEK 3.7-3 Amendment No.:
55, 60, 99