ML20151C414

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Proposed Tech Specs Changes Reflecting Replacement of 125 Volt Dc Station Batteries & Chargers During Upcoming Refueling Outage
ML20151C414
Person / Time
Site: Cooper Entergy icon.png
Issue date: 03/25/1988
From:
NEBRASKA PUBLIC POWER DISTRICT
To:
Shared Package
ML20151C408 List:
References
NUDOCS 8804120428
Download: ML20151C414 (2)
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3.9 BASCS The general objective of this Specification is to assure an adequate source of electrical power to operate the auxiliariea during plant operation, to operate facilities to cool and lubricate the plant during shutdown and to operate the engineered safegucrds following the accident. There are three sources of ac electrical energy available; namely, the startup transformer, the emergency transformer and two diesel generators. The de supply is required for switch gear and engineered safety feature systems. This supply consists of two 125V DC and two 250V DC batteries and their related chargers. Specification 3.9.A stater. the required availability of ac and de power; i.e., active off site ac sources and the required :aount of on site ac and de sources.

Auxiliary power for CNS is supplied from the startup transformer and the normal transformer. Both of these transformers are sized to carry 100% of the station auxiliary load. The emergency transformer is about one third the si=e of these two transformers and is equal in size to both emergency diesel generators.

The startup transformer and the emergency transformers are the offsice power sources. Their vo,1tage is monitored by undervoltage relays which provide low voltage protection for the erergency buses, khenever the voltage setpoint and time delay limit for the undervoltage relays have been exceeded, the emergency buses are automatically disconnected from the offsite power source.

I .5 the startup or emergency transformer is lost, the unit can continue to operate since the ur.it auxiliary transformer is in service, and the emergency or startup transformer and the diesels are available.

If both the star cup and emergency transformers become inoperable, the power level must be reduced to a value where by the unit can safely reject the load and continue to supply auxiliary electric power to the station.

In the normal mode of eperation, the startup and emergency transformers are energi:ed and two diesel generators are operable. One diesel generator may be allowed out of service based on the availability of power from the startup transformer and the fact that one diesel generator carries sufficient engineered safeguards equipment to cover all breakers. With the startup transformer and one diesel generator out of service, the off site transmission line corresponding to the emergency transformer must be available. Upon the loss of one on site and one off-site power source, power would be available from the other immediate off site power source and the two operable on site diesels to carry sufficient engineered safeguards equipment to cover all breaks. In addition to :hese two power sources, removal of the Isolated Phase Bus "quick" disconnect links would allow backfeed of power through the main transforner to the unit auxiliary transformer and provide power to carry the full station auxiliary load. The time required to perform this operation is comparable to the time the reactor could remain on RCIC operation before controlled depressuri:ation need be initiated.

Once each operating cycle , during shutdown, either a se rvic e test or performance discharge is performed on the 125 volt batteries. The performance discharge test is performed in lieu of the ser"ice test when a battery shows signs of degradation. Degradation is indicated when battery capacity drops more than 10% of rated capacity from its average on previous performance tests, nr is below 85% of the manufacturer's rating.

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LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS _

3.9.A 4.9.A (cont'd.)

3. The pilot cell voltage is 2.15V minimum and specific gravity 1.195 minimum, corrected for 77'F and electrolyte level.
b. Every quarter, the following para-meters shall be verified. The actual values shall be measured and logged:
1. The electrolyte level of each connected cell is between the minimum and maximum level in-dication marks.
2. For each connected cell, the voltage is 2.15V minimum and specific gravity is 1.190 minimum, corrected for 77'F and electrolyte level. The averag+ specific gravity of B. Operation with Inoperable Equipment all connected cells will be a minimum of 1.200.
1. Whenever the reactor is in Run Mode or Startup Mode wi.h the reactor not in a 3. The alectrolyte temperatures Cold Condition, the availability of in a representative sanple of electric pcwer shall be as specified cells, consisting of at least in 3.9.A.1, except as specified in every sixth cell, are within 3.9.8.1. 25'F.
a. Incoming Power c. Once each operating cycle the 125V battery charger will be tested to
1. From and after the date incoming power verify that the charger can supply is not available f rom a startup or emer- 200 A= peres at 125V for four hours.

gency transfor=er, continued reactor l operation is permissible under this d. Once each operating cycle, during condition for seven days. At the end shutdown, one of the following tests of this period, provided the second will be performed:

source of incoming power has not been made immediately available, the NRC 1. A battery service test to verify must be notified of the event and the that battery capacity is adequate plan to restore this second scurce. to supply the emergency load During this period, the two diesel profile, generators and associated critical buses must be demonstrated to be 2. A performance discharge test, in operable. lieu of the above service test, once every five years to verify

2. From and after the date that incoming that battery capacity is at least power is not available from both start- 85% of the manufacturer's rating, up and emergency transformers (i.e.,

both failed), continued operation is 3. A performance discharge test, in permissible, provided the two diesel lieu of the above service test, generators and associated critical when the battery shows signs of buses are demonstrated to be degradation or has been in service seventeen years or longer.

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