Research
Current Research Projects
Modeling and characterization of a-uranium to accelerate metallic fuels development
Funding Source: Idaho National Laboratory – Laboratory Directed Research and Development (LDRD)
Metallic fuels such as U-Zr and U-Pu-Zr are being proposed for certain new reactor designs, such as microreactors and the Versatile Test Reactor (VTR). Idaho National Laboratory (INL) can support metallic fuel development via fuel material research and the Bison fuel performance code. The existing metallic fuel performance models are empirical and do not match existing data very well. To accelerate materials discovery fuel design timelines and to improve fuel performance models, mechanistic (physics-based) models of fuel swelling, fission gas venting and fuel creep are necessary. The alpha-uranium phase exists in U-Zr and U-Pu-Zr fuel and significantly contributes to fuel behavior, but many fundamental materials properties and mechanisms of alpha-uranium are lacking. This work provides for atomistic modeling to understand the mechanisms of irradiation damage in alpha-uranium and the effect of interfaces. These atomistic modeling simulations will be performed in collaboration with an experimental characterization campaign to construct and inform a mesoscale evolution model of defect migration and evolution and the impact on microstructure.
Advanced Computational Modeling and Experimental Benchmarking of the Thermophysical Properties of Molten Salt Systems applicable to Molten Salt Reactor Design
Funding Source: Idaho National Laboratory – Laboratory Directed Research and Development (LDRD)
A significant knowledge gap exists in the data for the fundamental properties relevant to fuels and coolants for molten salt reactors (MSRs) that needs to be addressed in order to expedite the technical readiness level of the MSR design concepts. The US-DOE has identified the need to better understand, predict, and optimize the physical properties and thermochemical behavior of molten salts. This work will construct a computational framework for rapid evaluation of equilibrium salt properties, validated to existing experiments. This underlying framework will provide the ability to systematically obtain the equilibrium volume, energy, heat capacity and thermal expansion of salts as a function of composition and temperature in a consistent and coherent manner. This work will leverage previous computational studies on molten salt systems.
Subsequently, this framework will be utilized and extended to include investigations of extrinsic species within salts, as well as unique compositional salt constructions that are beyond the current experimental knowledge.
Radiation Enhanced Diffusion of U, Mo and Xe in U-Mo alloys for research reactor applications
Funding Source: U.S. Department of Energy, Office of Material Management and Minimization, National Nuclear Security Administration
A monolithic UMo fuel with low enriched fuel is proposed in place of the high enrichment UMo fuels used in research reactors. Qualification of this new type of fuel requires the fuel to maintain stable and predictable behavior throughout its lifetime in-reactor. Mechanistic fuel models are being developed that both correspond to existing experimental data on fuel swelling and can be applied to irradiation conditions beyond the experimental scope. In order to develop such mechanistic models, accurate fuel property data is required and must be obtained from either experiments or lower length scale modeling methodologies. One such parameter of critical importance is the species diffusion in UMo, with special emphasis on fission gas diffusion. There exists experimental data on high temperature, intrinsic diffusion of U and Mo. The Microstructural Modeling Working Group formed under the USHPRR program atomistically calculated the radiation driven diffusion coefficients. However, no such data on radiation enhanced diffusion in UMo alloys exists. In support of the USHPRR program, this subcontract supports the calculation of radiation enhanced diffusion of U, Mo and Xe in UMo fuels for application to fission gas swelling mechanistic models.