Behavior of cesium molybdate, CsMoO, in severe accident conditions, 1; Partitioning of Cs and Mo among gaseous species

Do, Thi Mai Dung*; Sujatanond, S.*; Ogawa, Toru

In order to better understand the behavior of cesium in the severe accident of the LWR, the high-temperature chemistry of CsMoO in HO+H gas was studied. The pseudo-binary system, CsMoO-MoO, was thermochemically modeled with Redlich-Kister formulation to form a basis to analyze the high-temperature behavior of CsMoO. The model prediction was compared with the thermogravimetric measurements of CsMoO in dry and humid argon, which revealed that the mass-loss rate was enhanced in the humid atmosphere. Thermochemical model was further applied to predict the partitioning of cesium and molybdenum among gaseous species in the BWR core degradation condition typical of Short-Term Station Blackout.