Containment - Boundary Flashcards
What are the 5 fission product barriers?
Fuel Fuel Cladding RPV and Primary system boundary Primary Containment Secondary Containment
What is the purpose of Primary Containment?
Provides a barrier for release during LOCA DBE to:
control release of fission products to secondary containment;
Limit pressure increase in primary containment
What are the design conditions of Primary Containment?
Designed to accommodate the pressures and temperatures which would result from or occur subsequent to a failure equivalent to a circumferential rupture of a major recirc line.
What are the allowable TS parameters of Primary Containment?
Max Temp: 150F
Max DW Press: 1.5psig (Designed to withstand 68psig internal, 2psig external(-2psig internal))
Max Torus Temp: 95F with no test
Torus Level: 14ft 6.5in to 14ft 10.5in
How does DW pressure react during a storm?
Pressure increases due to lower barometric pressure outside containment.
What is the purpose of the Refueling Bulkhead?
During refuel, prevents leakage of water from reactor well to drywell; enabling vessel flooding.
How is the DW equipment hatch sized?
Large enough to more Recirc Motor in and out.
What are the deisgn parameters for the Torus?
62psig internal (1psig external) at 281F Water volume sized to limit temp rise to 50F following LOCA
What is the purpose of the Torus
Provides a volume of water to act as a heat sink for the DW;
Provides suction water source for LPCI, CS, and HPCI(backup);
Sized to limit pressure rise to less than design pressure should all DW N2 discharge to Torus
How do we (normally) raise and lower torus level?
Raise: Demin Water by gravity drain CST through HPCI min flow
Lower: By Operating LPCI and sending water to Hotwell, Other Unit Torus, OR Radwaste
Why is temperature monitored by TS 3.3.3.1?
To ensure there is not a gross breach of containment
Why do the Torus downcomers exhaust below the torus water level?
Min water level Ensures that a 50F change in water temp is adhered to and ensures condensation and scrubbing of discharge occurs.
Max Water Level ensure air space large enough to accommodate all N2 from DW
How many Torus to DW vacuum breakers are there?
12 - 2 installed on size of the DW/Torus Vent Lines
What is the purpose of the DW/Torus Vacuum breakers?
Limit water level variation inside torus downcomers to 2ft during accident AND
prevent exceeding -2psig external pressure of DW.
DW to Torus DP maintained at ~1psid
Prevents water from being drawn up vent pipes
What are the setpoints for the Torus/DW Vacuum breakers?
Begin opening at 0.15psid, expected to be full open by 0.5psid (TS Requirement).
