ML20116D312

Proposed Tech Specs,Reflecting Correction to Bases Section 3.9 Re Emergency Diesel Fuel Tank Level Instrumentation

ML20116D312
Person / Time
Site:	Pilgrim
Issue date:	10/26/1992
From:	BOSTON EDISON CO.
To:
Shared Package
ML20116D309	List: BECO-92-124, Forwards Corrected TS Bases Section 3.9.Error Discovered During Electrical Distribution Sys Functional Insp (Edsfi) Edsfi Rept 50-293/91-80 Re Emergency Diesel Fuel Tank Level Instrumentation ML20116D312
References
NUDOCS 9211050301
Download: ML20116D312 (1)

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The general objective of this Specification is to assure an adequate source of electrical power to operate the auxiliaries during plant operation, to operate facilities to cool and lubricate the plant durinq shutdown, and to operate the

-engineered safeguaras following an accident. There are three sources of a-c

• x ' electrical energy available; namely, the startup trancformer, the diesel generators and the shutdown transformer. .The d-c supply is required for switchgear and engineered safety feature systems. Specification 3.9.A states the' required availabilit of a-c and d-c power; i.e., an active off-site a-c

, 4 source, a back-un source of off-site a-c power and the maximum amount of on-

> site a-c and d-c sources.-

The diesel fuel supply consists of two (2) 25,000 gallon tanks. Level instrumentation provides operators the information necessary to ensure a minimum supply of 19,800 gallons in each tank.

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Auxiliary power for PNPS .is supplied .from two sources; either the unit -

g auxiliary transformer or tne startup transformer. -Both af these transformers are sized to carry 100% of the auxilicry load. If the startu;) transformer is

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lost, the unit can_ continue to operate since the unit auxiliary transformer is

. in service, the shutdown _transformet is available, and both diesel generators are operational.

If the startup and shutdown transformers are both los o t e reactor power

' level must be reduced to a value whereby the unit coulc safely reject the load and continue to. supply auxiliary electric power to the station.

,In the normal moue of operation, the startup transformer is energizM, two diesel . generators.and the shutdown transformer are operable. One diesel generator may be allowed.out-of service. based on the availability-of power

from the startup transformer, the shutdown

transformer and the fact that one diesel. generator carries sufficient engineered safeguards quipment to cover

'all breaks. 'With.the shutdown. transformer and one diesel generator out of service, both.345kV supply lines must be available for the_ st vtup 1 transformer.

• llpan 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 one operable ton-site diesel to carry sufficient engineerer' safeguards equipment to cover all' breaks. In addition to then two power s,,nrces, removal of the Isolated

Phase Bus 1 flexible; connectors would allow backfeed of power through _the main

transformer to the unit au.xiliary transformer and provide power to carry the full - sta' icn

auxiliary load. The time required to perform this_ operation.is comparable.to the time tht reactor could remain on RCIC. operation before controlled depressurization need be initiated.

- A battery charger is sun tied with each of the 123 and 250 volt batteries and, ir_ addition, (1) a 125 vult shared back-up battery charger is' supplied which

Amendment _.140 198 l

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