Development of models of boiling pools for hypothetical LMFBR subassembly accident and applications to SCARABEE tests

During the hypothetical LMFBR subassembly accident (BTI = total instantaneous blockage), one has to consider the possible melting and then the boiling of part of the reactor materials : fuel and steel (from clad and possibly from the wrapper). This gives rise to a boiling pool (BP) which strongly influences the subsequent phenomena (wrapper failure, materials propagation out of the subassembly etc.). In this paper we first present the modelling. It is the system of MESCLA codes (Melange en Ebullition Sodium Combustible Acier), including the three codes MESCLA-S, MESCLA-P and MESCLA-T, each of them suitable for a particular situation. The second part of the paper deals with the experiments. Simulation water experiments and four SCARABEE experiments, as far as BP are concerned, are analyzed. (orig.)