Containment Hydrogen Recombiners - .5 Flashcards
What is the purpose of the Containment Hydrogen Recombiners?
to control and reduce H2 and O2 concentrations under post-LOCA conditions
What happens when the Hydrogen recombiners system isolates? and what isolates it?
blower stops, heaters deenergize, cooling valve closes.
- Hi-Hi Reaction chamber temp >1422F
- Hi-Hi Heater well temp >1422F
- Hi Return Gas Temp >250F
Auto resets as long as switch is still in operate
What are the Hydrogen Recombiner heater trips?
- Heater Outlet Temp >1300F
- Gas Temp >1200F (2/3 way through the heater)
- Low-Low gas flow <40% rated
- Reaction Chamber wall temp >temp controller setpoint (1422F)
- Heater Wall Temp HiHi>1422
- Return Gas Temp Hi 250F
- Cycling on TIC
What do the Hydrogen Recombiner isolation valves close on?
- LOCA level 2 (-38”)
- Hi-Hi Drywell Pressure (>1.68psig)
- Rx Building Exhaust Hi Rad (>1x10-3 uci/cc)
- Manual PCIS initiation
What cools the hydrogen recombiners?
RHR provides cooling to the recombiner spray coolers and returns it to the Torus. Since the tap from ‘A’ RHR is inside of the HX isolation valves, the ‘A’ HX must be in service to provide cooling. Does not matter for ‘B’ RHR
What is the suction and discharge of the hydrogen recombiners?
drywell to the torus air space
What will happen to drywell pressure when the hydrogen recombiner is in operation?
pressure will decrease
How do the heaters in the hydrogen recombiner work?
System has trickle keepwarm heaters designed to heatup to operation within 2 hours
are there any interlocks associated with the hydrogen recombiner skid startup?
at a temperature of 1300F at the wall of the coiled heater pipe while the reaction chamber wall temperature is < 1150F will automatically shut off the heaters (it is assumed that a spontaneous reaction has occurred before the gas has reached the reaction chamber).
