Overview of severe accident research activities performed in the Lacomeco Project at Karlsruhe Institute of Technology

Abstract

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.

The LACOMECO platform provides European organizations access to experimental facilities at Karlsruhe Institute of Technology (KIT) designed to study the remaining severe accident safety issues, including the coolability of a degraded reactor core, corium coolability in the reactor pressure vessel, melt dispersion to the reactor cavity, and hydrogen mixing and combustion phenomena in the containment. The KIT facilities are unique in its specified field and the experiments are designed to complement other European experimental platforms to form a coherent European nuclear experimental network. The LACOMECO platform includes: 1) QUENCH facility designed for the investigation of early and late phases of core degradation in prototypical geometry for different reactor designs and cladding alloys; 2) LIVE facility, a large-scale 3D facility for the investigation of melt pool behavior in the lower head of reactor pressure vessel; 3) DISCO facility, the only operating facility worldwide able to investigate the melt dispersion to the reactor cavity and direct containment heating; 4) HYKA facility with a number of large and medium scale experimental test vessels addressing hydrogen behavior in containment under well controlled conditions. Six experiments were defined in the LACOMECO project addressing the high and medium priority safety issues defined by the Severe Accident Research Priorities (SARP) group of the Severe Accident Research Network of Excellence (SARNET). Three experiments have already been performed, the main results obtained are discussed in the paper: - QUENCH-16 test in the QUENCH facility test aimed at study the slow oxidation of fuel rod bundle in air; - DISCO-FCI test in the DISCO facility aimed at investigation of ex-vessel fuel coolant interaction; - HYKA-DETHYD tests in the HYKA facility aimed at investigation of the critical layer thickness for hydrogen- air detonation propagation in semi-confined geometry. Three experiments will be performed in 2012, the main objectives and the status of the preparation are presented: - LIVE-CERAM test in the LIVE facility test aimed at examination of the dissolution kinetics of KNO3 ceramic crust by KNO3/NaNO3 melt; - HYKA-HYGRADE test in the HYKA facility aimed at investigation of hydrogen combustion in hydrogen concentration gradients and with obstructed geometries prototypical of conditions in LWR containments: - HYKA-UFPE test in the HYKA facility aimed at scaling- down of hydrogen combustion phenomena in nuclear power plant containments for numerical code validations.