Live L4 and Live L5L Experiments on Melt Pool and Crust Behaviour in the RPV Lower Head

Abstract

LIVE-L4 and LIVE-L5L experiments investigated thermal hydraulic behavior of corium pool in the RPV lower head with a 3D test vessel LIVE. The simulant material is 80%-20% KNO3-NaNO3. Transient and steady-state parameters such as melt temperature, heat flux distribution through the vessel wall as well as crust formation characteristics were obtained. The two tests demonstrated that transient events like melt relocation and change of decay power facilitate crust deformation and change of crust thickness. The dimensionless melt temperature and heat flux through wall during the steady state can be well described independent of power density. However the dimensionless melt temperature and heat flux are dependent on the pool height. A low pool has stronger focusing effect at the upper surface than in a high pool.