Materials and Chemistry for Molten Salt Systems: General Materials and Chemistry I
Sponsored by: TMS Structural Materials Division, TMS: Corrosion and Environmental Effects Committee, TMS: Nuclear Materials Committee
Program Organizers: Stephen Raiman, University Of Michigan; Raluca Scarlat, University of California, Berkeley; Jinsuo Zhang, Virginia Polytechnic Institute and State University; Kumar Sridharan, University of Wisconsin-Madison; Nathaniel Hoyt, Argonne National Laboratory; Michael Short, Massachusetts Institute of Technology
Wednesday 8:30 AM
March 2, 2022
Room: 203B
Location: Anaheim Convention Center
Session Chair: Michael Short, MIT
8:30 AM
Recovery of Purified Cerium Metal via Metallothermic Reduction after Chlorination-based Purification: Sierra Freitas1; Mario Alberto Gonzalez1; Chao Zhang2; Devin Rappleye3; Michael Simpson1; 1University of Utah; 2Lawrence Livermore National Labratory; 3Brigham Young University
In support of development of a metal purification process based on conversion of impure metals via hydriding followed by chlorinating, options for reducing purified metal chlorides back to metallic form were evaluated. Metallothermic reduction of pure CeCl3 was tested using lithium and calcium as reducing metals with and without a molten salt flux. Direct contact of lithium with CeCl3 was problematic, thus motivating the use of a molten salt flux (LiCl or NaCl-CaCl2). CeCl3 was found to have a high solubility in both proposed flux mixtures. Lithium metal dissolved in LiCl, however, appeared to form a low-density alloy with the resulting Ce metal. Water was demonstrated to be an effective rinse media for recovered ingots, washing away undesired phases without increasing oxygen content. The effects of the form of the added reducing metal, crucible dimensions, and mixture hold times above cerium melting temperature will be presented.
8:50 AM
Electrochemical Sensor for Real-time O2- concentration Measurements of a Direct Oxide Reduction: Forest Felling1; Mario Gonzales1; Chao Zhang2; Devin Rappleye3; Michael Simpson1; 1University of Utah; 2Lawrence Livermore National Laboratory; 3Brigham Young University
During direct oxide reduction (DOR) of metal oxides with Ca in CaCl2, salt-soluble CaO is generated. Real-time measurement of the CaO concentration can, thus, be an effective way to measure reaction kinetics and determine the progress of the DOR process. Previously, Zhang et. al. reported that cyclic voltammetry (CV) with tungsten electrodes can accurately measure the CaO concentration up to 0.1 wt% in molten CaCl2. As a first step to testing this measurement method during DOR operation, the CV response was verified up to 10 wt% CaO. Results of CV in the molten CaCl2 will also be reported during reduction of CeO2 with Ca metal.
9:10 AM
Crystal Structure Evolution of UCl3 from Room Temperature to Melting: Sven Vogel1; A. David R. Andersson1; Marisa J. Monreal1; J. Matthew Jackson1; S. Scott Parker1; Gaoxue Wang1; Ping Yang1; Jianzhong Zhang1; 1Los Alamos National Laboratory
Uranium trichloride, UCl3, is actively researched to develop and improve applications ranging from molten salt reactors to actinide processing, including spent fuel reprocessing. Here, we report for the first time the crystal structure evolution between room temperature and melting point from in situ high temperature neutron diffraction to quantify e.g. the thermal expansion of the hexagonal a and c lattice parameters. The results are compared to DFT calculations. The melting point of UCl3 is determined by differential scanning calorimetry to be 1108.2K.
9:30 AM
System for Chemical Analysis of Molten Salts: Diego Zometa Panigua1; 1NEXT Lab
The NEXT Lab plans to build a molten salt research reactor that relies on molten FLiBe for the primary loop. To prepare for the reactor, we want to understand better the chemistry of molten FLiNaK, corrosion products, and isotopes produced. Our proposed apparatus would allow us to perform small-scale experiments and extraction of 99Mo in the conditions of the reactor. This apparatus contains molten FLiNaK in a vessel made of the same alloy as the reactor. The salt is sparged with known amounts of molybdenum hexafluoride (MoF6) and potential fission fragments. Their interaction with the salt and corrosion products is studied with the aid of a carrier gas, which displaces them into a nickel tube where they may deposit. A secondary gas system fluorinates Mo that deposited in the tube and converts it back into MoF6, allowing it to continue its path into a carboy with an alkaline solution.
9:50 AM Break
10:10 AM
The Versatile Forced Convection Fluoride Loop (VeFoCoFLoo): Stephen Raiman1; Randi Mazza1; Aslak Stubsgaard2; Thomas Pedersen2; 1Texas A&M University; 2Copenhagen Atomics
Molten salt loops are an important part of the worldwide effort to build a working molten salt reactor (MSR). Thermal convection loops are often used for materials compatibility studies, but they lack the pressure needed to drive flow through realistic components. Large-scale pumped loops are useful for gathering critical data on thermal hydraulics and component performance, but they are difficult and expensive to operate. The VerSatile Forced Convection Fluoride Loop (VeFoCoFLoo), pronounced ve-FOH-coh-floo) at Texas A&M is a new facility that enables cost-effective experimental studies of materials and chemistry for MSRs. Based upon the 5th Generation Copenhagen Atomics Pumped Portable Molten Salt Loop, the VeFoCoFLoo was designed with an innovative modular heating and cooling system to accelerate testing of salt-facing materials and key MSR components. This talk will discuss the capabilities of the facility, and show preliminary data to validate its operation.
10:30 AM
Thermophysical Property Measurements and Modeling of Molten Salts: Ryan Gallagher1; Can Agca1; Abbey McAlister1; Paul Rose1; Alex Martin1; Jake McMurray1; N. Dianne Bull Ezell1; Shane Henderson1; Robert Lefebvre1; Anthony Birri; 1Oak Ridge National Laboratory
Molten salts are being considered for high temperature thermal energy storage and as a heat transfer fluid for several energy application such as concentrating solar power and nuclear reactor concepts. Quality thermophysical property data are critical for the design and deployment of these systems. These data are equally valuable for benchmarking predictive chemical modeling techniques. Existing property data for many salt systems are relatively scarce and challenging to measure. In this work, the density and viscosity of LiF-NaF-KF eutectic molten salt have been measured experimentally. Temperature and composition dependent Redlich-Kister functions have been used to generate binary interaction parameters in the LiF-NaF-KF system. These binary interactions have been used in the extrapolation of thermophysical properties of this ternary system. Details of the techniques and methods as well as the discussion of the results and comparison to existing computational and experimental data will be provided.