Theoretical study of sodium-water surface reaction mechanism

Kikuchi, Shin  ; Kurihara, Akikazu ; 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 study, we investigated the surface reaction mechanism in the SWR by ab initio method. The potential energy profiles of the dissociations of HO and OH were obtained. The estimated rate constant of the former was much larger than the latter.