Materials in Nuclear Energy Systems (MiNES) 2021: Fuels and Actinide Materials- Thermal Properties, UN and UC Fuels I
Program Organizers: Todd Allen, University of Michigan; Clarissa Yablinsky, Los Alamos National Laboratory; Anne Campbell, Oak Ridge National Laboratory
Wednesday 4:00 PM
November 10, 2021
Room: Grand Ballroom
Location: Omni William Penn Hotel
Session Chair: Todd Allen, University of Michigan
4:00 PM Invited
Utilization Potential for the Molten Salts Thermal Properties Database – Thermochemical (MSTDB-TC) in Operational and Safety Analysis for MSRs: Theodore Besmann1; Johnathan Ard1; Jacob Yingling1; Juliano Schorne-Pinto1; Mina Aziziha1; Mahmut Aslani1; Clara Dixon1; Matthew Christian1; Amir Mofrad1; Kaitlin Johnson2; Jake McMurray2; 1University of South Carolina; 2Oak Ridge National Laboratory
An extensive thermochemical database, the Molten Salt Thermal Properties Database – Thermochemical (MSTDB-TC), has been developed and continues to be expanded to provide for computing detailed thermochemical states for salt and related systems for MSRs. The MSTDB-TC is designed for stand-alone use with equilibrium calculational software, notably FactSage, or with codes such as the open-source Thermochimica which can be coupled to reactor performance and other applications. In the current work, the use of the database in computing reactor states as a function of burnup and consideration of potential accident analysis such as the determination of key species vapor pressures have been explored.
4:40 PM
Determination of Chromium Corrosion Potential in the Na-K-Mg-U(III) Chloride Molten Salt: Jacob Yingling1; J. S. Pinto1; J. C. Ard1; T. M. Besmann1; K. E. Johnson2; J. W. McMurray2; 1University of South Carolina; 2Oak Ridge National Laboratory
Significant strides in the development of the Molten Salt Thermal Properties Database – Thermochemical (MSTDB-TC) will allow the extensive thermodynamic description of salt systems relevant to the design, operation, and regulation of molten salt reactors (MSRs). Given the essential material compatibility requirements for MSR designs, MSTDB-TC provides open access to reliable thermodynamic models useful for prediction of multi-component phase equilibria and other complex processes like corrosion. Chromium in structural materials presents a particular challenge for its formation of halide compounds in salt systems. In this presentation, new phase equilibria measurements for the Cr-U(III) chloride pseudo-binary and Na-Mg-U(III) chloride pseudo-ternary systems will be reported, and their use in the development of predictive phase equilibria for the Na-K-Mg-U(III) chloride salt system is demonstrated. Additionally, the temperature and composition space favorable to inhibit corrosion with chromium is explored.
5:00 PM
Insights into Prediction of Thermodynamic Properties for Chloride Salts for Generation IV MSRs: Juliano Schorne Pinto1; Jacob Yingling1; Matthew Christian1; Amir Mofrad1; Mahmut Aslani1; Theodore Besmann1; 1University of South Carolina
A crucial issue for the development of molten salt reactors (MSRs) is the lack of thermodynamic information for its main constituents, i.e., fuel and/or coolant. For example, enthalpies of liquid-liquid mixing for uranium and plutonium trichloride with alkali metal chloride systems are limited. However, they are important to reliably model thermodynamic properties required from equilibrium calculations of complex systems present in MSRs. The work reported here supports the development of thermodynamic functions through empirical correlations coupled with numerical modeling to predict the enthalpy of mixing for unexplored AkCl-UCl3 and AkCl-PuCl3 (Ak=alkali element) systems. The results contribute to the development of the Molten Salt Thermal Properties Database-Thermochemical (MSTDB-TC), an open-source compendium for MSR applications.
5:20 PM
Molten Salt Thermal Properties Database-Thermochemical (MSTDB-TC) Status and New Assessment of MF-UF4 (M = Li, Na, K, Cs) Systems: Johnathon Ard1; Juliano Schorne-Pinto1; Jacob Yingling1; Theodore Besmann1; Jake McMurray2; 1University of South Carolina; 2Oak Ridge National Laboratory
The Molten Salt Thermal Properties Database-Thermochemical (MSTDB-TC) is a freely licensed resource supporting thermodynamic modeling of MSR-relevant fluoride and chloride salt systems. It continues to be expanded with additional components and higher order systems by the University of South Carolina in coordination with Oak Ridge National Laboratory. The current status of the MSTDB-TC is discussed, including newly added and assessed systems. The MF-UF4 (M = Li, Na, K) systems have been previously modeled using the modified quasi-chemical model in the quadruplet approximation. However, these models failed to obtain a reliable representation of the liquid phase when interpolated to higher order systems. It was necessary to introduce multiple endmembers for UF4 to accommodate observed variations in coordination numbers in the melt. A new model was therefore developed for the MF-UF4 (M = Li, Na, K) systems, and to these has been added the newly assessed CsF-UF4 system.