Thermodynamic and thermophysical properties of plutonium trichloride

This paper describes the characterisation of pure PuCl 3 synthesised in-house at JRC-Karlsruhe. The sample purity was evaluated using X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). High-temperature XRD was employed to determine the thermal expansion coefficients of the solid phase, while DSC was used to investigate the melting behaviour, the enthalpy of fusion and the high temperature heat capacity. The low-temperature heat capacity of PuCl 3 was investigated using a Physical Property Measurement System (PPMS-9, Quantum Design) allowing the calculation of the standard entropy of PuCl 3 (s). The volatilisation of PuCl 3 was studied using Knudsen Effusion Mass Spectrometry (KEMS). Thermodynamic parameters, including enthalpies of vaporisation and sublimation, were derived from vapour pressure data. The boiling point was extrapolated from vapour pressure results. Thermodynamic calculations of the vapour pressure were performed and compared with experimental findings.