An Evaluation Methodology Development and Application Process for Severe Accident Safety Issue Resolution

Table 1

Identification of severe accident processes and phenomena for generic ALWR.

Phenomena	Safety Issue
(1) Thermal-hydraulic and fuel rod degradation	Hydrogen control/core debris Coolability
(2) Core melt progression (degradation of core structure)	Hydrogen control/core debris Coolability
(3) Core melt relocation to lower head	Hydrogen control/core debris coolability
(4) Oxide/metal separation	Hydrogen control/core debris coolability
(5) Crust formation and failure	Core debris coolability
(6) In-vessel debris formation	Core debris coolability
(7) External reactor vessel cooling (in-vessel retention only)	Core debris coolability
(8) RPV failure modes	Containment performance/hpme
(9) In-vessel fuel-coolant interaction	Containment performance
(10) High-pressure melt ejection	HPME
(11) Steam/hydrogen transport	Hydrogen Control/Containment Performance
(12) Hydrogen recombination	Containment Performance
(13) Hydrogen combustion	Containment Performance
(14) Ex-vessel steam explosion	Containment Performance
(15) Molten core-concrete interactions and melt spreading	Hydrogen control/core debris coolability/containment performance
(16) Ex-vessel core debris stabilization	Core debris coolability/containment performance
(17) Long-term containment heat removal	Containment performance
(18) Fission product transport	Containment performance