ML022410078
| ML022410078 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 08/27/2002 |
| From: | NRC/NRR/DLPM/LPD3 |
| To: | |
| References | |
| TAC MB3042 | |
| Download: ML022410078 (6) | |
Text
3.0 LIMITING CONDITIONS FOR OPERATION 4.0 SURVEILLANCE REQUIREMENTS
- 2. Both diesel generators are operable and capable of feeding their designated 4160 volt buses.
- 3. (a) 4160V Buses #15 and #16 are energized.
(b) 480V Load Centers #103 and #104 are energized.
- 4. All station 24/48, 125, and 250 volt batteries are charged and in service, and associated battery chargers are operable.
B. When the mode switch is in Run, the availability of electric power shall be as specified in 3.9.A, except as specified in 3.9.B or the reactor shall be placed in the cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
- 1. Transmission Lines From and after the date that incoming power is available from only one line, reactor operation is permissible only during the succeeding seven days unless an additional line is sooner placed in service providing both the emergency diesel generators are operable.
200 I 3.9/4 .9 Amendment No. 51, 104 129
I 3.0 LIMITING CONDITIONS FOR OPERATION 4.0 SURVEILLANCE REQUIREMENTS 3.0 IMIINGCONITINS FR OERAION4.0SURVILLNCEREQIREENT
- 2. Reserve Transformers If offsite power sources are made or found to be inoperable for any reason such that Specification 3.9.A.1 is not met, reactor operation is permissible only during the succeeding 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> unless such B. 3. Standby Diesel Generators offsite sources are sooner made operable, provided that either 1R or 2R Transformer is operable. a. 1) Each diesel generator shall be manually started, loaded and operated at
- 3. Standby Diesel Generators approximately rated load for at least 60 minutes once every month to
- 1) From and after the date that one of the I a.
diesel generators is made or found to be demonstrate operational readiness.
inoperable, reactor operation is permissible 2) At least once each Operating Cycle during only during the succeeding 7 days provided shutdown simulate a loss of offsite power in that the operable diesel generator is conjunction with an ECCS actuation test demonstrated to be operable within signal, and:
24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
This test is required to be completed (a) Verify de-energization of the emergency busses and load shedding regardless of when the inoperable diesel generator is restored to operability. from the emergency busses.
The operability of the other diesel (b) Verifying diesel starts from ambient generator need not be demonstrated if the conditions on the auto-start signal and diesel generator inoperability was due to is ready to accept emergency loads preplanned preventative maintenance or within ten seconds, energizes the testing. emergency busses with permanently connected loads, energizes the
- 2) If both diesel generators become auto-connected emergency loads in I proper time sequence, and operates inoperable during power operation, the reactor shall be placed in the cold for greater than five minutes while its shutdown condition. generator is loaded with emergency loads.
3.9/4.9 201 Amendment No. 25, 51, 77 129
T 3.0 LIMITING CONDITIONS FOR OPERATION 4.0 SURVEILLANCE REQUIREMENTS
-I-
- b. For the diesel generators to be considered b. 1) Once a month the quantity of diesel fuel I operable, there shall be a minimum of 38,300 gallons of diesel fuel (7 days supply available shall be logged.
for 1 diesel generator at full load @ 2500 2) During the monthly generator test, the KW) in the diesel oil storage tank. diesel fuel oil transfer pump and diesel oil service pump shall be operated
- 3) Once a month a sample of diesel fuel shall be taken and checked for quality
- c. When a diesel generator is required to be operable, maintain air pressure for both c Verify each required operable diesel associated air starting receivers generator air start receiver pressure is
> 165 psig.
_>165 psig once per month.
- 1) With one diesel generator starting air receiver pressure < 165 psig, restore both starting air receivers pressure to
_:165 psig within 7 days, or declare the associated diesel generator inoperable.
- 2) With both diesel generator starting air receivers pressure < 165 psig but
=-125 psig, restore one starting air receiver to _> 165 psig and enter TS LCO 3.9.B.3.c.1, or restore both starting air receivers pressure to _>165 psig within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. If neither action can be accomplished within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, declare the associated diesel generator inoperable.
- 3) With both diesel generator starting air receivers pressure < 125 psig, immediately declare the associated diesel generator inoperable.
3.9/4.9 202 Amendment No. 3r-75-,80 129
Bases 3.9:
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 safeguards equipment following an accident.
AC for shutdown requirements and operation of engineered safeguards equipment can be provided by either of the two standby sources of power (the diesel generators) or any of the three active sources of power (No. 1 R, No. 2R, or No. 1AR transformers). Refer to Section 8 of the USAR.
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 established. The plant's main generator is not given credit as a source since it is not available during shutdown.
The plant 250 V dc power is supplied by two batteries. Most station 250 V loads are supplied by the original station 250 V battery. A new 250 V battery has been installed for HPCI loads and may be used for other station loads in the future. Each battery is maintained fully charged by two associated chargers which also supply the normal dc requirements with the batteries as a standby source during emergency conditions. The plant 125 V dc power is normally supplied by two batteries, each with an associated charger. Backup chargers are available.
The minimum diesel fuel supply of 38,300 gallons will supply one diesel generator for a minimum of seven days of full load (2500 KW) operation. Actual fuel consumption during this period would be 33,096 gallons, but the minimum tank level has been established at the higher 38,300 gallon value to allow for instrument inaccuracy, pump suction vortexing, tank volume uncertainties, and the location of the suction piping within the tank. Additional diesel fuel can normally be obtained within a few hours. Maintaining at least 7 days supply is therefore conservative.
Each diesel generator starting air receivers have the capability of providing a minimum of at least three (3) engine starts without any assistance from the air compressors when maintained at greater than or equal to 165 psig. If one starting air receiver is below its required pressure of 165 psig, restore both starting air receivers pressure to _>165 psig within 7 days. The 7 days to restore pressure to _> 165 psig is acceptable because there is sufficient air pressure to start the associated diesel generator a minimum of three (3) times. If the action cannot be performed within 7 days, declare the associated diesel generator inoperable. With both diesel generator starting air receivers pressure < 165 psig but _125 psig, restore one starting air receiver to _>165 psig and enter TS LCO 3.9.B.3.c.1, or restore both starting air receivers pressure to _ 165 psig within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. If neither action can be accomplished within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, declare the associated diesel 3.9 BASES 204 Amendment No. 41, 51, 75, 77, 80, 1O0a 129
Bases 3 9 (Continued):
generator inoperable. The 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> to restore one of the starting air receivers to > 165 psig and entering the TS LCO 3.9.B.3.c.1, or restoring both starting air receivers to >_165 psig within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> is acceptable based on the remaining air start capacity, the fact that most diesel generator starts are accomplished on the first attempt, and the low probability of an event during this brief period. If both starting air receivers for the same diesel generator are below 125 psig, immediately declare the associated diesel generator inoperable.
In the normal mode of operation, power is available from the offsite sources. One diesel may be allowed out of service based on the availability of offsite power provided that the remaining diesel generator is demonstrated to be operable within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This test is required even if the inoperable diesel is restored to operability within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Thus, though one diesel generator is temporarily out of service, the offsite sources are available, as well as the remaining diesel generator. Based on a monthly testing period (Specification 4.9),
the seven day repair period is justified. (1)
(1) "Reliability of Engineered Safety Features as a Function of Testing Frequency", I.M. Jacobs, Nuclear Safety, Volume 9, No 4, July - August 1968.
204a 3.9 BASES Amendment No. 129 I
Bases 4 9:
The monthly test of the diesel generator is conducted to check for equipment failures and deterioration. Testing is conducted up to equilibrium operating conditions to demonstrate proper operation at these conditions The diesel will be manually started, synchronized to the bus and load picked up. It is expected that the diesel generator will be run for one to two hours. Diesel generator experience at other generating stations indicates that the testing frequency is adequate to assure a high reliability of operation should the system be required.
In addition, during the test when the generator is synchronized to the bus it is also synchronized to the offsite power source and thus not completely independent of this source. To maintain the maximum amount of independence, a thirty day testing interval is also desirable.
The Surveillance Requirement for diesel generator starting air receivers ensures that, without the aid of the refill compressors, sufficient air start capacity for each diesel generator is available. The system design requirements provide power to start each diesel generator engine from two independent air starting systems. Each system consists of a pair of compressed air starting motors, an air dryer, strainer, air line lubricator, and related storage tanks that provide 100 percent redundancy for each diesel generator's starting air system. Starting at a nominal pressure of 200 psig, each air starting system has adequate capacity to start its associated diesel generator five times without recharging. The limit of 165 psig provides minimum air pressure to support three diesel generator engine starts, from each of the two starting air receivers associated with each diesel generator, without recharging, this provides for a total of six (6) starts for the associated diesel generator. The monthly surveillance requirement frequency for verifying the pressure in each starting air receiver takes into account the capacity, capability, redundancy, and diversity of the AC sources and other indications available in the control room, including alarms, to alert the operator to below normal air start pressure. During the monthly load test of the diesel generators, the diesel fuel oil transfer pump and diesel oil service pump will be operated. A sample of diesel fuel will be taken monthly to assure that the quality remains high.
The test of the emergency diesel generator during the refueling outage will be more comprehensive in that it will functionally test the system, i.e., it will check diesel starting and closure of diesel breaker and sequencing of loads on the diesel. The diesel will be started by simulation of a loss of coolant accident. In addition, an undervoltage condition will be imposed to simulate a loss of offsite power. The timing sequence will be checked to assure proper loading in the time required. The only load on the diesel is that due to friction and windage and a small amount of bypass flow on each pump. Periodic tests between refueling outage check the diesel to run at full load and the pumps to deliver full flow. Periodic testing of the various components plus a functional test at a refueling interval are sufficient to maintain adequate reliability.
Although station batteries will deteriorate with time, utility experience indicates there is almost no possibility of precipitous failure. The type of surveillance described in this specification is that which has been demonstrated over the years to provide an indication of a cell becoming irregular or unserviceable long before it becomes a failure.
In addition, the checks described also provide adequate indication that the batteries have the specified ampere-hour capability.
3.9 BASES 205 Amendment No O,-100a 129