Abstract
Currently, a knowledge gap exists in the available data and understanding of thermophysical properties relating to fresh fuel salts, especially those containing plutonium. These data are necessary for designing, constructing, and licensing future commercial molten-salt reactors. Thermophysical properties, such as melting temperature, salt stability, density, and heat capacity were ascertained using NaCl-PuCl3 (36 mol% PuCl3) and a more sodium rich composition containing 25 mol% PuCl3. The NaCl-PuCl3 salt mixture was synthesized for this study and contained 63.4 mol% NaCl, 36.3 mol% PuCl3 and was 99.7% pure. Upon heating, the NaCl–PuCl3 eutectic was stable at temperatures up to 800 °C. The onset of melting occurred at 451 ± 3 °C, and the enthalpy of fusion was determined to be 23.0 ± 1.4 kJ/mol. Heat capacity measurements in the liquid phase ranged from 107.7 to 91.3 J/mol.K, with an average value of 104.6 ± 11.4 J/mol.K between 500 and 650 °C. Three independent trials of the molten NaCl-PuCl3 salt found the density to be ρ(T) = 3.8589 – 9.5342·10-4 T(°C). In addition, ab initio molecular dynamic simulations to calculate density and heat capacity values are included.
| Original language | English |
|---|---|
| Article number | 122636 |
| Journal | Journal of Molecular Liquids |
| Volume | 387 |
| DOIs | |
| State | Published - Oct 1 2023 |
Funding
The team would like to acknowledge facility operators at the Idaho National Laboratory (INL) for supporting this research. The salt synthesis work was supported under CRADA 21CRA25 “Flowing Molten Salt Microloop Testing Using Actinide Bearing Salts” in collaboration with TerraPower, LLC. Elemental and isotopic analysis and the majority of the thermophysical property research was supported by the Molten Salt Reactor Campaign, work package number AT-22IN070502 “Thermochemical and Thermophysical Property Database Development – INL.” Finally, density measurements were, in part, supported through the INL Laboratory Directed Research and Development program under Department of Energy's Idaho Operations Office Contract DE-AC07-05ID14517. Computational studies were supported by the Molten Salt Reactor Campaign, work package number: AT-22PN070506 “Thermophysical Property Database Development-Modeling – PNNL.” This research used resources of the National Energy Research Scientific Computing Center; a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Portions of this work were supported by the LDRD program at Oak Ridge National Laboratory. Author Contributions. Toni Y. Karlsson aided in salt synthesis, designed heat capacity experiments, performed data analysis and evaluation, and wrote the manuscript. Scott C. Middlemas executed melting temperature and heat capacity measurements. Manh-Thuong Nguyen and Vassiliki-Alexandra Glezakou executed the AIMD computations and wrote the modeling portion of the manuscript. Michael E. Woods designed, analyzed, and summarized the density experiments. Kevin R. Tolman performed analysis and interpretation of XRD data. Steven D. Herrmann designed the salt synthesis path and provided technical expertise. Juliano Schorne-Pinto performed CALPHAD calculations for MSTDB heat capacity data, reviewed the manuscript, and provided technical expertise on heat capacity discussions. Ryan D. Johnson and Shawn E. Reddish performed all hands-on work for fuel handling during the synthesis and density measurements. Stephen A. Warmann was responsible for supervision of experiments, technical advice, and project management. Patricia D. Paviet provided partial funding and project execution. All authors contributed to the review and editing of the manuscript. Additional Information. Correspondence and request for information should be made to Toni Karlsson relating to experimental work and Manh-Thuong Nguyen for AIMD computations. The team would like to acknowledge facility operators at the Idaho National Laboratory (INL) for supporting this research. The salt synthesis work was supported under CRADA 21CRA25 “Flowing Molten Salt Microloop Testing Using Actinide Bearing Salts” in collaboration with TerraPower, LLC. Elemental and isotopic analysis and the majority of the thermophysical property research was supported by the Molten Salt Reactor Campaign, work package number AT-22IN070502 “Thermochemical and Thermophysical Property Database Development – INL.” Finally, density measurements were, in part, supported through the INL Laboratory Directed Research and Development program under Department of Energy’s Idaho Operations Office Contract DE-AC07-05ID14517. Computational studies were supported by the Molten Salt Reactor Campaign, work package number: AT-22PN070506 “Thermophysical Property Database Development-Modeling – PNNL.” This research used resources of the National Energy Research Scientific Computing Center; a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Portions of this work were supported by the LDRD program at Oak Ridge National Laboratory.
Keywords
- Ionic liquids
- Molten salt
- Plutonium
- Thermodynamic properties
- Transuranic