EW- Essential Cooling Water Flashcards
What must be done prior to opening the EW to NC cross tie valves? Why?
close NC non-priority heat load isolation valve so EW water doesn’t get transferred to NC system
What is the EW surge tanks low level control point?
25”
What is the purpose of the Essential Cooling Water system?
Removes heat from all essential components required for normal and emergency shutdown of the plant and rejects the heat to the Spray Pond
Upon a loss of NC, can be lined up to provide cooling water for the Fuel Pool Cooling Heat exchangers, Reactor Coolant Pumps, CEDM normal ACUs, and nuclear sample coolers and normal chillers
Intermediate barrier between RC and Essential Spray Pond to reduce possibility of radioactive leakage to the environment
What is the rated flow for a typical EW pump?
16,650 gpm at 138 ft TDH
When does the EW pump room ACU start?
when the pump starts
At what level in the EW Surge tank would the normal makeup valve automatically close to prevent feeding a leak?
14”
How does the EW system interface with the EC system?
EW removes heat from EC chillers
EC sends chilled water through the EW pump room ACU
What else starts when the EW pump starts?
EW pump room ACU (cooled by Essential Chilled Water)
What is the tech spec related to the EW system?
two EW trains must be OPERABLE
What is the normal source of makeup water to the EW? Backup sources?
Normal: Demineralized Water System (DW)
Backup: Chemical Waste System (CM) cooling water hold up tank
Safety related backup: Condensate Transfer and Storage System (CT)
If we were to drain the EWHXs, what system would I drain them to?
Oily Water System (OW)
What signals would automatically start the EW pumps?
LOP (20 seconds after EDG output breaker closes)
CSAS
SIAS
CREFAS
CRVIAS
AFAS 1 and 2
When aligning the EW system to cool the SFP HXs, what must be done prior to opening the EW valves?
closing the NC supply and return isolation valves for the HX
What electrical protection is available to the EW pump motors?
Overcurrent and ground fault protection trips that actuate an 86 lockout relay
Why do we pressurize the EW Surge tanks with nitrogen?
To prevent oxygen from getting into the system that could lead to corrosion
Why do we have EW radiation monitors?
Where are they located?
Detect RC or reactor auxiliary system leak into the EW system (measure gross gamma activity)
next to respective EW pump
What system provides power to the Train ‘A’ EW to NC Cross-tie valves?
PH
What is the purpose of the EW surge tanks? What is the capacity and pressure of the EW surge tanks?
Allow for makeup water to be added to the system
Accommodate for changes in system volume due to temperature changes
Provide a means of detecting leakage into or out of the system
Provide NPSH to the EW pumps
1000 gallons at 15 psi
When Train “A” EW is cross-connected to NC, what two conditions would close the Train “A” EW to NC cross-tie valves?
EW “A” Surge Tank Lo Level (17”)
SIAS
What could be used as an emergency source of makeup water to the EW system?
Fire Protection system
What over pressure protection is provided for the shell side of the EWHX? Why is the tube side SP pressure higher than the EW shell side?
relief valves
to prevent radioactive material leaking to the environment
How is EW affected upon a loss of PK?
Loss of control power to EW system surge tank solenoid valves. (Operator will have to bypass the solenoid valves and manually makeup the surge tanks)
Loss of remote operation of Class 4160 V breakers and breaker indications
What is the capacity of the EW chemical addition tanks? Where are they located?
11 gallons
next to respective EW pump
Where are the EWHXs located?
100’ aux building west side
When would EW cool the SFP HXs?
When NC is not available
What is the EW surge tanks High Level control point?
30”
What flow requirement is associated with the EW system?
720 gpm through the essential chiller condensers is necessary to provide sufficient cooling capacity to accommodate a design basis accident in the hottest part of the summer when the EW water temp is 132F
What system provides power to the EW pumps?
PB
What are the NC system priority loads?
RCP Seal Coolers, Thrust bearing coolers, and motor coolers
CEDM Normal ACU
Nuclear Sample coolers
One of the normal chillers
What flows does the EW cooling water hold up tank receive?
EW surge tank overflow and EWHX floor drains
Using the EW chemical addition tanks, we add chemicals to maintain pH and nitrite concentrations at what values?
pH between 8.0 and 10.5
nitrite between 400 and 800 ppm
Where are the EW pumps located? What is the normal status of the suction and discharge valves?
70’ Aux Building
locked open
Where are the EW surge tanks located?
120’ aux building
Where are the Radiation monitors in the EW system?
bypass loop around each EW pump
What is the design outlet temperature of the EWHX?
<135*F
What happens when the EW system receives signals from the ESFAS?
EW-NC cross-tie valves auto close on SIAS
EW pumps start on LOP and load sequence
What system powers the EW system instrumentation?
PN
Where are the EW to NC priority load cross tie valves located?
70’ aux building next to SDCHX
What happens if I lose EW?
If one train becomes inoperable, a shutdown will have to be performed after a period of time
When shutdown, you will have a loss of cooling to SDC heat exchanger, which will affect decay heat removal
