Gaseous Radwaste(GR) Flashcards
What is the purpose of the Gaseous Radwaste system ? What kind of gases does it collect ?
-Collects & processes potentially radioactive gases generated in plant
-High Activity gases primarily hydrogen & Nitrogen
What kind of gases does Gaseous Radwaste Collect?
-High Activity gases primarily Hydrogen & Nitrogen,are collected & stored in oxygen free system to decay short-lived isotopes
How does GR interface with PH system ?
PH provides power to GR Containment Isolation Valves
How does GR interface with PK system ?
PK provides power to Class Solenoid Operated Valves
How does GR interface with NH system ?
NH provides power to Waste Gas Compressors
How does GR interface with NK system ?
NK provides power for Aux. relays in Radwaste Control Panels
How does GR interface with NN system ?
NN provides power to GR instrumentation in Radwaste Control Room
How does GR interface with CH system ?
CH inputs into GR system from:
-RDT
-Gas Stripper
-VCT
-VCT Relief
How does GR interface with Fuel Handling system(FH)?
FH has gaseous input to GR from Containment Refueling Failed Fuel Detector Vent & Dry Sipping Aux. Pump
How does GR interface with Service Gases(GA)?
LP nitrogen is used for:
-Initial System Purge
-System Purge to allow for maintnence
-Auto purge from high oxygen senses in Surge Header
How does GR interface with Radwaste Building HVAC(HR) ?
-High activity portion of GR discharges to HT system
-Low Activity aerated waste gas also vented from selected equip. to HR system
How does GR interface with NC system ?
Nuclear Cooling Water cools Waste Gas Compressors
How does GR interface with Radioactive Waste Drains(RD) system ?
RD system receives liquid wastes from GR system
How does GR interface with Radiation Monitoring(SQ) system ?
Monitors discharges gases, provide alarms, & closes discharge header isolation valves
How does GR interface with Nuclear Sampling (SS) system?
Samples lines for:
-Gas Surge Header
-Surge Tank
-Each Decay Tank
Returns lines from O2 analyzers back to Gas Surge Tank & Header
How does GR interface with ESFAS ?
Closes RDT Vent header Containment isolation valve on a CIAS
Where does Gas Header receives potentially Radioactive gas inputs from ?
-RDT
-Containment Refueling Failed Fuel Detector Vent
-Dry Sipping Aux. Pump
-Gas Stripper
-VCT
-VCT Relief
-O2 Analyzers discharge
When will Gas Surge Header RDT Containment Isolation Valves automatically close ?
They will close on a CIAS
What is the 20 gallon condensate pot used for ?
Taps off Gas Surge Header to collect condensate that formed in the lines from RDT
What’re the Oxygen Concentration alarm set points for Gas Surge Header ?
HI alarm: >2% alarm will activate in Main Control Room & Radwaste Control Room
HI-HI alarm: 3.75% will activate alarm & after 5 minutes will Nitrogen Auto Dilute
What happens when HI-HI Oxygen Concentration alarm is reached ?
Will activate alarm & after 5 minutes it will Nitrogen Auto- Dilute the Gas Surge Header
Where is the discharge of the oxygen analyzers directed back to ?
It’s directed back to the Gas Surge Header
What does the Surge Gas Surge Tank do ?
Absorbs fluctuations in gas volume entering system to minimize Waste Gas Compressor operating time
What is the design temperature of the Waste Gas Surge Tank plastic liner ?
Plastic liner design temp. is 200F
What’re the Waste Gas Compressors used for ?
They pump LP gas from Waste Surge Tank to the Waste Gas Decay Tank for holdup prior to release
What is the Mode Selector switch used for on the Radwaste Control Panel ?
Two position switch that chooses, which Gas Compressor will be the lead or standby compressor
With both Waste Gas Compressor hand switches in auto, what pressure will the lead & standby compressor start ? When do the compressors turn off ?
-Lead Compressor starts @3psig HI pressure in Waste Gas Surge Tank
-Standby Compressor starts @5psig HI-HI pressure in Waste Gas Surge Tank
-Will turn off @1.5psig Waste Gas Surge Tank pressure
What cools the Waste Gas Compressors ?
Requires Nuclear Cooling Water
Where are Waste Gas Compressors powered from ?
Powered from NH
What happens to running Waste Gas Compressors when an Nitrogen Auto-Dilution of the Gas Surge Header occurs?
Compressors will trip & are reset by taking handswitch to “stop” and then back to “Auto”
What should the oil system be maintained at for each compressor ?
Sight glass should be maintained between Full mark & 1/2 above Full Mark
How often should each Waste Gas Compressor be ran ?
Each compressor must be ran at least weekly to maintain Oil Priming for compressor
How often is the “Lead/Standby” selector switch be swapped ?
Selector switch for compressor should be swapped twice per week
What must you do to Waste Gas Compressor if the compressor is not ran for 7days?
Oil must be primed manually via priming pump hand wheel
What’re the Waste Gas Decay Tanks used for ?
Used to store waste gas for radioactive decay before being discharged to atmosphere
What is the design pressure of plastic liner inside the Waste Gas Decay Tanks ?
Has design pressure if 380psig
What is the Waste Gas Decay Tanks setpoint for the relief valve ? Where does it relieve to ?
-It has a setpoint at 380psig
-Relieves to Waste Gas Surge Tank
What pressure is a waste gas decay tank isolated ? How long must it remain isolated ?
-Has to reach 340psig to be isolated
-Has to remain isolated for at least 45 days
Prior to releasing Waste Gas Decay Tank what must be done before releasing it to Radwaste Building Ventilation ?
Must have it sampled by chemistry
What happens if maintenance is scheduled for the tank ?
The tank will be completely released and purged with nitrogen
What must the control room do to allow the Radwaste control room to operate the GR Discharge Isolation Valves ?
They have to give you permissive by turning a hand switch in control room
What signals wi automatically close GR Discharge Isolation Valves ?
-Radwaste Building Exhaust fan A&B low DP
-High waste gas discharge flow
-High Waste Gas discharge pressure in radiation Monitor supply line
-High radiation level
What other valve will isolate if any of the GR Discharge Isolation Valves were to automatically close ?
The air supply solenoid will close , which will close the flow control valve (FV-33)
What’re the two mode of operations for the GR Discharge Flow Control Valve ? What do you control valve when in manual ?
-Has auto & manual pushbuttons
-Manual operations has a lever to adjust flow either fast feed & slow feed
What is the position of the flow control valve when the GR Discharge Isolation valves go open?
Flow control valve will slowly open slightly less than release permit limit
What is installed before the Radiation Monitor to prevent excessive flow through it ?
A flow limiting orifice is installed upstream that limit flow to 5 SCFM
How is the High Radiation level setpoint determined ?
-Based on the Gas Decay Tank being released
-Prior to release tank is sampled to determine radiation activity
-Radiation setpoint is, then set 3X higher than expected
How many oxygen analyzers are there? Which components of the GR system has a oxygen analyzer?
There are four oxygen analyzers
-Waste Gas Surge Header
-Waste Gas Surge Tank
-In-Service Waste Gas Decay Tank
-Fourth oxygen analyzer can be aligned to other components
What will happen on a 2% oxygen concentration ?
-Activates high oxygen alarm in main control room & Radwaste control room
What will happen when oxygen concentration is 3.75% ?
-HI-HI oxygen alarm will activate & after 5mins of alarming nitrogen auto dilute will occur
What components is nitrogen auto dilute aligned to ?
-Waste Gas Surge Header
-Waste Gas Decay Tank
-Upstream of Waste Gas Compressors
What happens to Waste Gas Compressors when a Nitrogen AutoDilute occurs ?
-Trips & locks out both Waste Gas Compressors
When the waste gas compressors trip on Nitrogen Auto Dilute, how do you reset them ?
Take both compressors to “stop” & return them to auto position
What might be the problem if the High Oxygen Analyzers of the Waste Gas Decay Tanks alarm, BUT the Waste Gas Surge Tanks didn’t alarm ?
There is most likely a Waste Gas Compressor leak
What is the TRM for explosive gas monitoring system ?
2 oxygen monitors must be operable
-Oxygen Monitor(Surge Tank)
-Oxygen Monitor(Waste Gas Header)
What is the TRM for the Concentration of oxygen in the GR system ?
Shall be limited to <2%
