The Evaporation Behavior of Volatile Fission Products in FLiNaK Salt

Molten salt reactor (MSR) was suggested for the one of the nuclear power plant concepts planned for generation IV. However, little study had been done on the severe accident at MSR. The one of the severe accident at MSR is considered that the molten salt with fuel will be exposed to air and some fission products will release to environment. The molten FLiNaK salt (LiF-NaF-KF: 46.5–11.5-42 mol%) with CsI(FLiNaK- CsI: 99-1 mol%) was evaporated and released gases were measured by mass spectrometry. The evaporated gases from above sample were mainly CsI and KI. The value of vapor pressure for CsI was low about ten to the first ∼ second power of vapor pressure for pure CsI at same temperature. Therefore, it is expected that FLiNaK prevents the release of CsI. On the other hand, despite KI were not included in original sample, KI released significantly.