Plant 100%
Gaseous waste panel annunciator “GAS WASTE FEED PREHTR OUT COND HI” and “AUX COND CONDUCT HI” come in.
What statement describes the plant’s auto response to the alarms?
the degasifier feed water heater steam supply valve CLOSES and the preheaters condensate divert valve diverts to the aux building sump
To where in the radioactive gaseous waste system does the containment vacuum pump discharge when running?
inlet of the process vent cooler
Which component in the gaseous waste system is responsible for the removal of radioactive isotopes stripped from the RCS by the degasifier prior to to being discharged through the site ventilation stack?
charcoal bed adsorbers
What describes the purpose of the time delay with shifting position of the degasifier stream outlet valve from “DRAINS DEGAS” to “LETDOWN DEGAS”?
prevents inadvertent RCS dilution
The gaseous waste system processes RCS letdown in order to:
reduce activity levels in the RCS by removing radioactive gases prior to entering the VCT
What would be the result on the GWS system if air is lost to the degasifier level control valve?
LV28 will fail OPEN, causing max flow out of the degasifier. Degasifier level will decrease and trips the recirc pumps, aligning letdown flow directly to the VCT
The process vent fans discharge to:
the site stack via the SLCRS duct OR the U3 TB stack via reactor plant ventilation
The degasifier is in the “letdown Degas” mode.
VCT/Degas letdown divert valve auto shifts to send letdown flow directly to the VCT.
What could be a direct cause of this action?
degasifier Lo-Lo level
In the radioactive gaseous waste system, the adsorbers function to:
delay the discharge of some radioactive gasses to allow for decay and permanent capture of radioactive iodine
Why must 3HVR*V42, U3 discharge to the site ventilation stack, be CLOSED if no process vent or SLCRS fans are available?
to prevent back flow to the U3 from the site ventilation stack
What is the immediate response of the GWS to a SIS actuation?
the process vents dampers CLOSE
The degasifier is operating in the “DRAINS DEGAS” mode. The degasifier mode switch is placed in the “LD DEGAS” position.
3GWS-AOV54 shifts to send degas effluent to the VCT.
Why the delay?
prevents dilution by ensuring that degasified drains are flushed to the BRS prior to sending return flow to the VCT
The plant is at 100% power and degasifier in “LD DEGAS” mode. A leak developes in the process gas piping at the top of the degasifier and the cubicle airborne radiation increases.
Which rad monitor will detect this and what will occur at the hi rad ALARM setpoint?
3HVR-RE12A
degas subsection valves shift to their fail positions and the recirc pumps trip
Where does the water trapped in the dryer skids flow after being removed from the process gas stream?
to the degasifier recirc pumps suction
What will auto CLOSE the waste gas process gas receiver discharge pressure control valve?
high effluent radiation sensed by the process gas monitor, 3GWS-RE48, downstream of charcoal adsorbers
Why is the process gas receiver maintained at a slightly positive pressure?
to prevent forming an explosive mixture by preventing oxygen inleakage
What daily check does the primary rounds operator make on the process gas receiver and why is this check made?
verifies hydrogen and oxygen concentrations are within limits to ensure that flammable concentrations do not exist
