Containment Inerting and Purge - .5 Flashcards
What is CIPS or?
Designed to reduce O2 Concentration to <4% in 4 hours or less, make it breathable, and provide a hard vent.
What are the 4 CIPS subsystems?
- Containment inerting and purge (CIPS)
- H2/O2 Analyzer (HOAS) for inerting and normal makeup
- Containment H2 Recombiner (CHRS)
- Containment Vacuum Relief (Vacuum Breakers)
What are the CIPS containment isolation valve trips?
- LOCA level 2 (-38”)
- Hi-Hi Drywell Pressure (>1.68psig)
- Rx Building Exhaust Hi Rad (>1x10-3 uci/cc)
- Manual PCIS initiation
What are the drywell pressure alarms and their setpoints?
- Hi – 1.5 psig
- Lo - .1 psig
- Hi-Hi – 1.68 psig
- Hi (Crids) – 1 psig
What do the HV-9372 A and C Dampers (Drywell Purge Supply and Exhaust Dampers) close on?
- LOCA level 2 (-38”)
- Hi-Hi Drywell Pressure (>1.68psig)
- Rx Building Exhaust Hi Rad (>1x10-3 uci/cc) – INTERTING SUPPLY ISOLATES AND DRYWELL PRESSURE STABILIZES – same with normal pressure makeup
- Refuel floor Exhaust Hi Rad (>2x10-3 uci/cc)
If your 9372A(inerting containment discharge path) closes via the refuel floor exhaust Hi-Rad (WITHOUT RBE), what will stop the the drywell from reaching 1.68#?
the blowout panels will blow at 1 psid which will prevent hitting 1.68# and discharge containment exhaust into the reactor building.
What is the power supply to the CIPS isolation valves and to what position do they fail? what position do the makeup and vent paths fail to on a loss of air?
All valves are powered from 1E and fail closed on a loss of power.
Normal makeup and vent path valves fail closed on loss of air
What must be in service when inerting?
Drywell coolers
What action can you take during the inerting process to promote proper mixing?
Torus to DW vacuum breakers are manually cycled
What ductwork is containment purging done through? are their any precautions and protections associated with this piping?
CPCS. CPCS has duct blowout panels(7 in total) that blow out at 1 plus or minus .25 psid. If they blow out it may take longer to purge.
What is the setpoint for the hardened Torus Vent Rupture Disc?
35 psig
Is a valve permit required for pressure control on a loss of DW cooling alone?
Valve permit is not required for pressure control – on a loss of DW cooling and no LOCA, valves may be opened for pressure control without a permit.
What is the temperature limit for inerting the drywell and why is it the limit?
During inerting, N2 temperature should not go below 40°F because cold N2 could cause the cooling of components below their NDT
Where does nitrogen makeup to the drywell come from?
via the “B” H2/O2 Analyzer Midpoint Connection HV-5019B
What are the tech spec basis for CIPS?
- Oxygen concentration maintained < 4% to ensure an event that produces hydrogen does not result in a combustible mixture inside the primary.
- As long as reactor power is less than 15% RTP, the potential for an event that generates significant hydrogen is low and the primary containment need not be inert. Furthermore, the probability of an event that generates hydrogen occurring within the first 24 hours of a startup, or within the last 24 hours before a shutdown, is low enough.
- However, the specific O2 limit of 4%, is there to ensure that the Oxygen concentration does not exceed flammable limits after a DBA (This seems obvious, but…).
