Strategy Evaluation for Cavity Flooding during an ESBO Initiated Severe Accident

Table 2

Sequences of the scenario cases in seconds.

Analysis purpose	Effect of intentional depressurization			Effect of cavity flooding			Effect of injection termination
Scenario ID	ase 1.1	ase 1.2	ase 1.3	ase 2.1	ase 2.2	ase 2.3	ase 3.1	ase 3.2	ase3.3
Event description	No operation	Early opening of valves	Delayed opening of valves	No injection	Early injection of the cavity	Delayed injection of the cavity	Continuous injection	Early termination of the injection	Late termination of the injection
Opening safety valves	--	6248 s/SG dry	9790 s/Core exit 922 K	9790 s	9790 s	9790 s	9790 s	9790 s	9790 s
Accumulator delivery	16,193 s	7803 s	10,486 s	10,486 s	10,483 s	10,486 s	10,483 s	10,483 s	10,483 s
Accumulator depleted	16,219 s	19,645 s	23,131 s	23,131 s	22,729 s	22,786 s	22,729 s	22,729 s	22,729 s
Relocation	14,527 s	25,877 s	28,617 s	28,617 s	26,196 s	27,936 s	26,196 s	26,196 s	26,196 s
Cavity injection	--	--	--	--	9790 s/Core exit 922 K	14,790 s/Delay 5,000 s	9790 s/Core exit 922 K	9790 s	9790 s
Terminating injection	--	--	--	--	Continuous injection	Continuous injection	Continuous injection	50,000 s	100,000 s
RV failure	16,182 s	29,583 s	34,562 s	34,562 s	N/A	N/A	N/A	88,926 s	N/A
Containment failure	137,191 s	N/A	N/A	N/A	158,231 s	185,485 s	158,231 s	N/A	N/A

N/A: no failure for 72 hours (259,200 s).