ML20083A139

Proposed Tech Specs,Adding Automatic Load Sequencer to Plant TS

ML20083A139
Person / Time
Site:	Vogtle
Issue date:	05/02/1995
From:	GEORGIA POWER CO.
To:
Shared Package
ML20082V304	List: ML20082V301 ML20083A139
References
NUDOCS 9505100055
Download: ML20083A139 (2)

Text

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Insert 1 Page B 3/4 3-1 The engineered safety features actuation system does not include an explicit functional unit for the automatic load sequencer. An inoperable loac' sequencer would affect the ability to detect and respond to a loss of power or undervoltage and thus is included with the instrumentation that must be available to meet the requirements of functional units 6.d. i. and i.i., as well as 8.a and b. Since the hardware is the same for each of these functional units, a common action statement is used. The mode of applicability for functional unit 6.d does not include mode 4 since the AFW is not required to be operable in mode 4; therefore, a footnote has been added that refers to functional unit 8.a and b.

which requires the instrumentation to be operable in mode 4.

An inoperable automatic load sequencer does not impact the operability of the automatic actuation logic and actuation relays (functional unit 1.b). The hardware referred to by this functional unit is not contained within the automatic load sequencer, but in the solid-state protection system. The effects of an inoperable automatic load sequencer is that the associated on site or ofTsite 4.16 kV emergency power sources may not correctly respond to an ESF or loss of power signal. The appropriate action for an inoperable automatic load sequencer is closely related to the action for an inoperable diesel generator and an associated offsite source with an energized 4.16 kV bus. The appronriate actions for an inoperable automatic load sequencer are included in specification 3.8.1.1 and are discussed in the basis for Technical Specification 3/4.8.1. Action statement 29 for inoperable undervoltage channels is commensurate with that for an inoperable automatic load sequencer, and its basis is enveloped by thejustification given for Technical Specification 3/4.8.1.

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Insert 2 Page B 3/4 8-1 The ACTION times specified for an inoperable automatic load sequencer are based on the times allowed when a combination of one diesel generator and one offsite circuit is inoperable. Under this condition the 4.16 kV Class IE bus would remain energized. The ACTION conservatively addresses any consequential effects of an inoperable load sequencer on other engineered safety features.

In Modes 5 and 6 the automatic load sequencer is necessary to automatically strip the loads from the IE bus and start the operable diesel generator in the event of a loss of otf site power (LOSP). Since the design basis LOCA is not applicable in Modes 5 and 6 tho automatic LOCA load sequencer function of the load sequencer is not required ,o be demonstrated as operable. Therefore, those surveillances that require sequencing oflo ids because of an SI signal are not required in Modes 5 and 6.

The loss of power and undervoltage functions are the aspects of sequencer operation that:

1) function to trip all closed breakers on the 4.16 kV Class lE bus on a loss of or degraded voltage; 2) start tne associated diesel generator; 31 close the breaker to supply power to the 4.16 kV Class lE bus from the associated diesel generator; and, 4) close the breakers tu supply power from the 4.16 kV Class IE bus to the LOSP required loads in the appropriate sequence.

During shutdown, the operability of the loss of power and undervoltage function for modes 5 and 6 of the automatic load sequencer is not affected by the inability to sequence and load equipment that is not required to be operable in Modes 5 and 6. Surveillances to show the operability of the loss of power and undervoltage function of the automatic load sequencer will only include that equipment that is required to be OPERABLE in Modes 5 and 6.

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