Normal Chilled Water (WC)

Question 1

How are the Normal Chilled water pumps controlled and what are their power supplies?

Answer 1

They are automatically started and stopped with the chiller package.

A: NHN-M19

B,C E02: NH.

Question 2

State the compressor start cycle for the A chiller.

Answer 2

Compressor start:
Circ pump starts and NCW valves open
23 (±10) seconds later – lube oil pump starts
28 (±10) seconds after LO pump starts, compressor starts

Question 3

Which of the following signals will trip the A normal chiller?

1. SIAS 2. CSAS 3. MSIS 4. DGSS

A. 1, 2, 3, 4

B. 2, 3, 4

C. 1 ONLY

Answer 3

C. SIAS, and it can be overridden.

Question 4

State the auto makeup and overpressure features associated with the WC surge tank.

Answer 4

Auto makeup from DW and overpressure with N2 to prevent corrosion in the WC system and to provide NPSH to the WC circ pumps.

Question 5

What are the containment isolation valve associated with the WC system? What signal will give them a close signal?

Answer 5

CIVs are MOV.

UV-63/CNMT/Check vlv
UV-61/CNMT/UV-62

CIAS signal.

Question 6

How will a loss of IA affect the WC system?

Answer 6

WCN-70/71(supply valves to Radwaste, Control, and Auxiliary building headers) fail closed.

This DOES NOT include the CCP room coolers
Temperature control valves on various different building ACUs will fail to through cooler position
This DOES include the CCP room coolers

Question 7

State the number, power supplies and relative capacity of the chillers.

Answer 7

Three large capacity chiller packages (Chillers A, B, C)
A Chiller: PBA-S03 (4.16 kV)
B Chiller: NBN-S01
C Chiller: NBN-S02

One small capacity chiller package (Chiller 2)
Power: NBN-S02
Operates as needed in conjunction with one or two of the larger units.