Kinetic and thermodynamic studies of reactional system (X-I-O-H) by high temperature mass spectrometry

High temperature mass spectrometry is used for analysis of vapors coming from iodine reaction with fission products in case of a severe nuclear accident in a pressurized water reactor. Two main ways are used, - (i) thermodynamic analysis of vaporization processes of CsOH, CsI and mixtures CsI-CsOH. - (ii) building a dedicated reactor for kinetic analysis of the recombination of atoms into these stables molecular species. The present study confirms the existence of Cs2IOH(g) molecule. Vapor pressures of gaseous molecules CsOH(g), Cs2O2H2(g) and Cs2IOH(g) have been determined. Molecular parameters of the mixed molecule have been estimated on the basis of the pure dimmers Cs2O2H2(g) and Cs2I2(g) and its enthalpy of formation are established. The acquisition of kinetic data needs a new reactor, the conception of which is presented in this work as well as qualification tests: thermal, flow regimes and pressure calibration tests. (author)