Service Cooling Water (SCW)

Question 1

List 10 loads on SCW

Answer 1

• main turbine lube oil coolers - main feed pump turbine lube oil coolers - #2 Heater drain pump lube oil and sample cooler - Electro hydraulic Control coolers - condensate pump motor upper bearings - condensate booster pump lube oil coolers - Generator exciter (2 coils/ cooler) - fuse wheel (2 coils/ cooler) - iso-phase bus coolers (2 coils/ cooler) - personnel access ac - TSC ac (U-1) - ops ready room ac - fw sample cooler, 72 - air compressors 05 and 06(booster pumps)(U-1) - reciprocating air comp 1-4 jacket coolers

Question 2

Auto starts on SCW pumps What must be done to stop pump that has been automatically started?

Answer 2

• low supply hdr pressure (46#) - running pump trips - manually Press the local reset push button

Question 3

What CW pump provides flow to what SCW hx?

Answer 3

CWP 1-1–>SCW hx 1-2 CWP 1-2–>SCW hx 1-1 CWP 2-1–>SCW hx 2-1 CWP 2-2–>SCW hx 2-2

Question 4

What is the alternate cooling supply to SCW? What other interlock should be aligned to CWP that has SCW lined up?

Answer 4

Screen wash pumps via pcv-152 to prevent 50psig design pressure of scw hx tubes from being exceeded, other units cwp can be aligned as a backup, firewater used to supply cooling during outages

Auto reclose cut in for CWP that has SCW lined up

Question 5

Precautions and limitations for SCW

Answer 5

• ensure in service SCW hx is lined up to CWP that has auto reclose cut in - prior xfr or draining SCW check with chemistry for disposal or proper chem control - when x-tie ing SCW to air compressors monitor indication of flow xfr between units to prevent overflowing head tank

Question 6

What controls are there in control room for SCW? What parameters are available on controller?

Answer 6

TCV-2, SCW hx bypass valve, shuts, more water through hx, temp lowers TCV-15, main lube oil cooler SCW flow control vlv TCV-16/17, feedwater pump lube oil cooler SCW flow control vlv P-process stream value S-setpoint being maintained V-valve position demand

Question 7

System layout and flowpath for SCW

Answer 7

Two pumps (one running, one stby) Discharge to hx (one on service, one stby) TCV-2 controls temp out of hx Header provides many loads in parallel One load has booster pumps due to remote location (05 and 06 compressors) Return header connected to head tank Pumps take suction from return header

Question 8

Tcv-2 scw hx bypass fails how? Keeps temperature at what value? How does the controller fail on loss of control power?

Answer 8

(ATO/FC)
80degF
Lost of control power fails as is and fail to manual when power restored