ASW

Question 1

Purpose of ASW?

Basic flowpath?

Alignment?

Answer 1

• Remove heat from CCW and reject to UHS
• intake (bar rack, traveling screen), pump suction, hx inlet valves, CCW hx, outlet valves, CWS-> outfall
• one pump man/on, other stby/off, flow through one hx

Question 2

Automatic starts for ASW pumps?

What starts require switch in auto?

Answer 2

• xfr to SU (10 sec delay)
• xfr to DG (10 sec delay)
• SI (22 sec delay)
• lo header pressure (40.5 psig) *
• UV on opposite bus *
• requires switch in auto

Question 3

Automatic trips of ASW pumps

Answer 3

O.C.
Load shed (4kv UV)

Question 4

What is only common failure that could take out both ASW pumps?

How is this prevented?

Answer 4

Common floor drain header => flooding in one pump room can go through drains and flood other room

• Back flow check valves installed in drain lines
• alarm @ 6” level
• design level 6’ (motor height)

Question 5

How is ASW pump motor able to breath since its in a watertight room?

Answer 5

• exhaust fan on anytime pump bkr closed
• intake and exhaust goes through ventilation shaft to outside
• vent shaft, 49.5’ elevation, with protected structure (waves)

Question 6

What is purpose of ASW-601, where is it controlled from?

Answer 6

Crosstie between units, allows one unit to supply other ASW

U-1 MCR (480v 1F)

Question 7

What are the air bottles in the CCW hx room there for?

Answer 7

The inlets to the CCW hx (ASW side) are air close, fail open valves.
If instrument air lost (100#) the bottles provide backup air to maintain valves closed so the in service CCW hx isn’t robbed cooling flow (8 hrs)

Question 8

Precautions and limitations for ASW

Answer 8

• do not fully close outlets to CCW hx (ASW side)
• always ensure she’ll side Press (CCW ) > tube side
  So ASW doesn’t leak in
• starting/ stopping ASW pump may cause auto start opposite unit ASW pump (low pressure)