High‐temperature mass spectrometric study of vaporization and thermodynamics of the Cs2O‐B2O3 system: Review and experimental investigation. (21st April 2021)

• Record Type: Journal Article
• Authors: Stolyarova, Valentina L.; Vorozhtcov, Viktor A.; Lopatin, Sergey I.; Shugurov, Sergey M.; Simonenko, Elizaveta P.; Simonenko, Nikolay P.; Kurata, Masaki; Costa, Davide
• Is Part Of: Rapid communications in mass spectrometry. Volume 35:Number 11(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-04-21
• Subjects: Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/rcm.9079
• Languages: English
• ISSNs: 0951-4198

Abstract

Abstract : Rationale: The compounds in the Cs2 O‐B2 O3 system are of particular interest for nuclear applications since cesium borates may be formed during accidents in nuclear reactors, affecting the rate of release of radiotoxic isotopes into the environment. Thus, information on the vaporization and thermodynamic properties of cesium borates is necessary for simulation and modeling of the isotope release processes taking place during the nuclear reactor accidents. Methods: Compounds in the Cs2 O‐B2 O3 system were synthesized by the co‐crystallization method with subsequent sintering. The sample characterization was carried out using XRD, TGA/DSC/DTA, IR spectroscopy, and ICP atomic emission spectroscopy. The vaporization and thermodynamics of the samples under consideration were investigated using an MS‐1301 mass spectrometer and a single molybdenum effusion cell. The electron ionization method was employed for ionization of the vapor species with an electron energy of 30 eV. The scale of the ionizing voltage was calibrated according to the traditional technique by measuring the appearance energy of gold in the mass spectrum of the vapor over pure gold. Results: The main vapor species over the samples in the Cs2 O‐B2 O3 system were CsBO2 and Cs2 B2 O4 in the temperature range 789–1215 K and in the concentration range 0.1–0.5 mole fraction of Cs2 O. The temperature dependences of the CsBO2 and Cs2 B2 O4 partial pressures over cesium borate were obtained in the temperature range 767–990 K. The CsBO2 and B2 O3 activities, the Gibbs energies of mixing, the excess Gibbs energies, the partial mole enthalpies of mixing, and total enthalpies of mixing were determined as functions of temperature and composition of the condensed phase. Conclusions: As the Cs2 O and B2 O3 activity values evidenced, negative deviations from the ideal behavior were observed in the Cs2 O‐B2 O3 system in the temperature range 800–1000 K. The total enthalpies of mixing and the Gibbs energies of mixing in the Cs2 O‐B2 O3 system were compared with the literature data, illustrating their mutual agreement.