Analysis Of Cabri-Bi1 Loss Of Flow Experiment

The Institute for Energy and Transport (IET) in collaboration with the project partners is conducting a validation of the new severe accident analysis code for Sodium-cooled fast reactors ASTEC-Na (Accident Source Term Evaluation Code). A series of experiments performed in the past (CABRI/SCARABEE experiments) were chosen to validate the developed ASTEC-Na code.One of the in-pile experiments considered during ASTEC-Na validation phase is CABRI-BI1; loss-of-flow transient without Transient Over Power (TOP) using low burn-up MOX fuel pin. The experiment resulted in a channel voiding as a result of sodium boiling and a clad melting. Only some fuel melting took place. The results of the ASTEC-Na calculation performed within the present work were in good agreement with the steady state and the overall fuel-pin disruption behaviour, which were characterised by a thermal pin-failure mode, observed in the CABRI-BI1 experiment. This paper describes the outcome of the analysis using ASTEC-Na as well as findings for future code improvements. The main attention during validation phase was given to modelling of fuel-clad heat transfer.