Investigation on ruthenium transport in highly oxidising conditions

This paper presents results from ruthenium release, transport and speciation experiments obtained in recent European studies. Experiments have shown that ruthenium may be released from the fuel already at a relatively moderate temperature, if the cladding is breached and if the flow contains oxygen. Furthermore, a significant fraction of released ruthenium is expected to be transported in the primary circuit in gaseous form. This work helps to resolve a severe accident safety issue related to fission product release in highly oxidising environment, which was indicated in the EURSAFE phenomena identification and ranking table (PIRT) [1]. Ultimately the goal of the ongoing projects is to improve modelling of ruthenium transport phenomena in severe accident codes such as ASTEC/Sophaero