Simulation of the Air Ingress Experiment Parameter SF4 Using ATHLET-CD

Abstract

The air ingress test PARAMETER SF4 was performed in July 2009 with the aim to investigate the behavior of a VVER bundle during reflooding after air ingress. Simulations are performed using the severe accident code ATHLET-CD. The results of the simulations show a good agreement in comparison to the experimental data during the pre-oxidation phase and in most bundle regions also during air ingress. The hydrogen generation is very close to the experimental data up to the beginning of quenching afterwards the total amount of H2 is underpredicted. Further improvement can be achieved by using a model to consider ZrN formation.