Normal Chilled Water (WC) Flashcards
Purpose of the WC system?
supplies chilled water to the cooling coils of the air handling units of:
containment, control, auxiliary, and radwaste buildings,
and for the coolers of the non-nuclear process sampling system.
How does WC interface with CEDMCS?
CEDM Control Cabinet Room ACU cooled by WC
How does WC interface with the CH system?
CHP room coolers cooled by WC
What does WC provide cooling to in Containment?
Containment Normal ACUs
How does the WC system interface with the Generator?
Generator collector Housing ACU cooled by WC
How is WC flow through the non-nuclear sample coolers regulated?
temperature control valve based on sample temperature
How do WCN-UV-70/71 HEADER isolation valves fail on a loss of IA?
How do individual room cooler cooling water valves fail?
closed
open
How does NC interface with the WC system?
what trips are associated with this?
cooling medium for the condenser of the chiller packages
Condenser low water flow trip
auto restarts when flow is restored
What major concerns exist when losing WC system?
Containment temperature (avg 117*F tech spec limit)
Main Generator collector housing temp gets too high (generator shutdown)
CEDMCS room high temp (could cause rod slippage)
What is the limit on the number of normal chillers that can run at the same time?
2 LNC and 1 SNC
Where do the normal chillers get power from?
WCN-E01A - PBA-S03 (trips on SIAS, can override)
WCN-E01B - NBN-S01
WCN-E01C & E02 - NBN-S02
What was the purpose of the Hot gas bypass on the normal chillers?
why were they removed?
prevent surging
when chilled water hits the low temperature setpoint, the line would direct a portion of the compressor discharge to the bottom of the cooler. This caused more of the refrigerant to flash, resulting in more flow
they were removed because surging means there isnt enough demand for the number of chillers in service and one should be secured
How does the condenser section work on the Normal Chillers?
NC removed heat from the refrigerant coming from the compressor
refrigerant condenses and falls to the lower portion of the condenser, called the thermal economizer
thermal economizer contains 12% of the tubes in the condenser section
What is the purpose of the flash economizer section of the Normal Chillers?
Provides an intermediate pressure reservoir for liquid refrigerant before it returns to the cooler
Where do the Normal Chiller Circulation pumps get power from?
P01A - SIAS LS panel NHN-M19
All others from NH
What system provides auto make up to the WC expansion tank?
what provides a cover gas?
How is leakage detected?
DW
N2
High/low level insturments
What are the WC containment isolation valves?
When do they auto close?
Supply
WCB-UV-63
WC-V039 (Check valve)
return
WCB-UV-61
WCA-UV-62
CIAS (can be overridden)
In the WC system, what trip is associated with the low chilled water temperature 38*F?
when can it restart?
low load recycle trip/restart
20 minutes after the star signal
