Reaction path analysis of sodium-water reaction phenomena in support of chemical reaction model development

Kikuchi, Shin  ; Ohshima, Hiroyuki; Hashimoto, Kenro*

In a sodium-cooled fast reactor (SFR), liquid sodium is used as heat transfer fluid to carry the energy from the reactor core to the steam generation (SG) system for power generation. If the heat transfer tube in the SG is failed, high pressurized water vapor blows into the liquid sodium and the sodium-water reaction (SWR) takes place. The extremely high temperature reaction jet formed by the SWR causes damage to the surface of the neighboring heat transfer tubes by thermal and chemical effects. Therefore, it is important to clearly understand the SWR for safety assessment of SG. In this work, we studied the surface reaction in the SWR by using ab initio calculations. The successive OH cleavages of a water molecule at the liquid sodium surface were focused. The possible reaction path and the related energies including the barrier heights were reported. The relative rates of the OH cleavages were also discussed.