—The thermal dehydration of GdCl3 ⋅ 6H2O crystalline hydrate is studied by synchronous thermal analysis and mass spectrometry using certified samples. The mechanism and the caloric effects of...

The mechanism and kinetic parameters of the interaction of the FLiNaK–CeF₃ melt with water vapors and oxygen in the air atmosphere were determined using Raman and IR spectroscopy, XRD analysis, and thermodynamic modeling of processes. The presence of the 4CeF_3(solution) + 6H₂O _(gas) + O_2(gas) = 4CeO_2(solid) + 12HF_(gas) reaction, which disturbs the fluoride melt homogeneity, was verified in situ by Raman spectroscopy adopted for high-temperature, chemically aggressive fluoride systems. Based on the obtained spectral data, the type of the kinetic equation, order, and rate constant of the chemical reaction were determined. The concentration of cerium dioxide was found to increase linearly in time and a zero reaction order with respect to CeO₂ was detected. The change in the concentration of CeO₂ over time at T = 510 °C is described by the equation C = 0.085t; the reaction rate constant is 0.085 mol. %∙min⁻¹. The obtained kinetic parameters may be used to model emergencies related with the depressurization of the coolant circuit or the working area of the molten salt reactor.

The structure and the conductivity of homogeneous CsCl–PbCl₂–PbO melts with different compositions are studied. The Raman spectra (RS) of the chloride and oxide–chloride melts containing lead oxide have been measured. It is found that the CsCl (71.3 mol %)–PbCl₂ (28.7 mol %) system with the addition of 12 mol % PbO and the CsCl (18.3 mol %)–PbCl₂ (81.7 mol %) system with the addition of 18 mol % PbO contain Pb₃O₂Cl⁺ oxide–chloride groups. The temperature dependences of the electrical conductivity are measured in the PbCl₂–CsCl chloride melts containing 28.7 and 81.7 mol % lead chloride and in homogeneous molten mixtures CsCl (71.3 mol %)–PbCl₂ (28.7 mol %) with the addition of 12 mol % PbO and the CsCl (18.3 mol %)–PbCl₂ (81.7 mol %) with the addition of 18 mol % PbO. Significant degradation of the ion conductive properties of the PbO–PbCl₂–CsCl oxide–chloride melts as compared to those of the PbCl₂–CsCl chloride electrolytes has been revealed. It is shown that the decrease in the electrical conductivity of the PbCl₂–CsCl oxide–chloride melts as lead oxide is added is due to the presence of Pb₃O₂Cl⁺ oxide–chloride groups.