Cesium Iodate – Vaporization Behaviour of Cesium Iodate in Molten Salt Reactor Fuel

If you are looking for high-quality products, please feel free to contact us and send an inquiry, email: brad@ihpa.net

cesium iodate, also known as Caesium Iodide or CsI, is a white crystalline solid which is used in fluoroscopy equipment as the input phosphor of an x-ray image intensifier tube. It is also an important ingredient in some iodine-containing medicines.

A major concern in the operation of a nuclear reactor is the release of radioactive materials into the environment, both actinides and formed fission products. Volatility is one of the driving forces for their release, and it is mainly determined by the chemical form that they take on, which can be influenced by their physical state.

In this study the vaporization behaviour of volatile fission products caesium and iodine in molten salt reactor fuel was investigated using KEMS (Kelvinator-Equivalent-Metal System) tracer tests. A very limited solubility of CsI in the LiF-ThF4 solvent is observed, and a clear immiscible region was found at 980 K. This resulted in a lower vapour pressure for the mixture than the elemental Cs, and was attributed to the fact that most of the iodine in this sample stabilized as iodide rather than in its much more volatile elemental form.

The iodide form of the fission product iodine was observed to behave much more conservatively than iodide in elemental form, and therefore reduce the iodine source term considerably. This finding is relevant for the characterization of the vaporization behaviour of CsI and iodide in a MSR molten salt fuel mixture, where both are considered to contribute significantly to the source term in accidental scenarios.