ML20093K339
| ML20093K339 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 07/17/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20093K342 | List: |
| References | |
| TAC-47494, TAC-47495, NUDOCS 8407310050 | |
| Download: ML20093K339 (2) | |
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- Two'separata,outside sources can' serve either unit's low voltage station e
e auxiliary transformer. One 1s a dir&#t feed from the unit's high voltage t
station auxiliary transformer and 'the second is from the other unit's high voltage station auxiliary transformer or the gas turbine via the 13,800 volt system tie bus H01.
Separation is maintained in the 4160-volt system to allow the plant auxiliary equipment to be arranged electrically so that redundant itecs receive their power from the two different buses.
For example, the safety injection pumps are supplied from the 4160 volt buses 1-A05 and 1-A06 for Unit No. 1 and 2-A05 and 2-A06 for Unit No. 2; the six service water pumps are arranged on 480-volt buses as follows: two on bus 1-B03, one un bus 1-B04, one on bus 2-B03 and two on bus 2-B04; the four containment fans are divided between 480-volt buses l-B03 and 1-B04 for Unit No.1 and 2-B03 and 2-B04 for Unit No. 2 and so forth.
Redundant valves are supplied from motor control centers 1-B32 and 1-B42 for Unit No. 1 and 2-B32 and 2-842 for Unit No. 2.
The pitnt DC electrical system has been modified so that each of the four instrument bus power supplies has its own battery and battery chargers One battery charger shall be in service on each battery so that tite batteries will always be at full charge in anticipation of a loss-of-ac power incident.
This ins,tres that adequate de power will be available for starting the emergency generators and other emergency uses.
4tr b4Q pgt The emergency generator sets are General Motors Corporation, Electro-Motive 8
{in Division, Model 999-20 Units rated at 2850 KW continuous, 018 power factor o
lSg 900 RPM, 4160 volts 3 phase, 60 cycle and consume 205 gallons of fuel per ou oc hour. Thus the 11,000 gallon supply in the Emergency Fuel Tank provides gg tsog sufficient fuel to operate one diesel at design load for more than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, ton.o Unit 1 - Amend....t No. 7(, 84 Unit 2 - Amendment No. 31, 88 15.3.7-4
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'In addition, it will be normal for Point Beach to keep one, or the equivalent
. of one, bulk storage tank ful,1 a't all!*tinha (55,000 gal, which is equal to about 10 days' supply). They are each capable of providing 3050 kw for a 30 minute period. The gas turbine is capable of providing 20,000 kw.
If only one 345KV transmission line is in service to the plant switchyard, a temporary loss of this line would result in a reactor trip (s) if the reactor (s) power icvel were greater than 50%. Therefore, in order to maintain continuity of service and the possibility of self sustaiaing operations, if less than one 345KV transmission line is in service to any operating reactor (s),
the power level of the affected reactor (s) will be limited to 50%.
If both 345/13.8KV station auxiliary transformers are out of service, only one reactor will be operated. The gas turbine will be supplying power to operate the safeguards auxiliaries of the operating reactor and acts as a backup supply for that unit's normal auxiliaries. Therefore, to prevent overloading the gas turbine in the event of a reactor trip, the maximum power level for the operating reactor will be limited to 50,%.
These conserv-ative limits are set to improve transmission system reliability only and are not dictated by safety system requirements.
References FSAR Section 8.
Unit 1 - Amendment No. 84 l
Unit 2 - Amendment No. 88 15.3.7-5