(268g) Radioisotope Target Dissolution Modeling and Simulation

The Radiochemical Engineering Development Center (REDC) at the Oak Ridge National Laboratory (ORNL) develops target material and processes the irradiated targets for producing radioisotopes of interest to the scientific community. The targets are irradiated at the High Flux Isotope Reactor at ORNL. This presentation describes system-level modeling and simulation of the dissolvers at the REDC (15 L and 170 L) for carrying out the caustic dissolution of the target cladding, followed by the acidic dissolution of the remaining oxide pellets. System-level of theory is used to describe the time-dependent chemical kinetics of dissolution of fully mixed systems including the solid, liquid and vapor phases. The modeling and simulation approach is similar to the dissolution of aluminum-cladded metal fuel in past research¹.

The dissolution of irradiated targets liberates volatile isotopes from the target matrix. Parallel research efforts are modeling the subsequent effluent propagation through a physics-based mass balance model tool. Results of effluent transport and temporal radionuclide profiles based on calculated target inventories and process models will also be presented.

1) Key, B., Sadasivan, P., Fallgren, A., Demuth, S., Aleman, S., de Almeida, V.. Chiswell, S., Hamm, L., Tingey, J., 2017 Facility Modeling Capability Demonstration Summary Report, LA-UR-17-20737, https://doi.org/10.2172/1342830.