Offgas Flashcards
What causes an Offgas System isolation?
High radiation levels on BOTH RE-13A/B (2 red lights)
What components are manipulated on a system isolation?
- AOV103 shuts
- The closing of AOV103 cause the Offgas pumps to trip on high pressure.
- Pump isolation valves and SAS M/U shut.
What is the Power Supply for RE-13A/B
UPS1B
What is the purpose of the Charcoal Adsorbers?
Adsorbs gas molecules, providing a minimum holdup time of 26 hours for krypton isotopes and 20 days for xenon isotopes. When the atoms decay, they form particulates (Rb and Cs) which become permanently lodged in the charcoal beds.
What is the Offgas Preheater isolation?
<240F
Isolates AOV1 & 11
(This isolation is bypassed during S/U)
What happens on a loss of IAS?
AOV 1, 11, 45, 52, 103 FAI
AOV 4, 5 Fail Open
What is the MAX amount of time the Charcoal Adsorbers can be bypassed?
7 days
What system is affected by the closure of AOV1
Automatic S/D of HWC
What parameter shows an indication of a Fire in the Adsorbers?
> 100F
Where are the Rad Monitors located?
Downstream of the dryers, Upstream of Charcoal Adsorbers.
What is the purpose of the HEPA Filters in the Offgas System?
Remove charcoal fines.
How long will condenser vacuum maintain with a closure of AOV103?
15 min
How is Offgas Steam preheated when entering the Offgas System?
Aux Steam in the Preheater.
How is Pressure and Temperature regulated in the Preheater?
A pressure indicating controller modulates pressure control valve PV71A to maintain recombiner inlet temperature approximately 290°F to the tube side of the preheater and limits pressure to 50 psig.
What happens on a loss of SAS to the vacuum pump inlets?
Lose automatic pressure control on the inlet to the vacuum pump.
What is indicated by the recombiner highest temp is at the outlet?
The catalyst is almost depleted.
What happens as moisture increases in the system/adsorbers?
Release Rate increases
What is the Flowpath of the System.
SJAEs
Preheater
Recombiner
Condenser
75 sec pipe
Dryers
Dewpoint
Rad elements
Charcoal
HEPA Filters
Vacuum Pumps
AOV103
Stack
How long can we operate with H2 analyzer OOS?
Do not operate >1week w/out H2 analyzer!
What is the Offgas condenser cooled by?
CCS
