(242b) Mesofluidic Exclusion of Large Particles for Nuclear Waste Applications

A key element of nuclear waste processing and treatment unit operations is the separation of suspended particles by size. For example, tank side cesium removal (TSCR) systems used to treat nuclear defense waste stored at the Hanford Site are working toward a requirement to remove particles larger than 10 µm, and the Hanford Waste Treatment and Immobilization Plant (WTP) pretreatment facility requires removal of particles larger than 310 microns. In these two example cases, removing large particles out of waste streams is important to protect the operation of downstream cesium ion exchange columns and the facility design basis for mixing and waste transfers, respectively. This presentation discusses a new mesofluidic separator that leverages fluid dynamic streamlines in column arrays to exclude large particles from waste streams without moving parts. Mesofluidic systems leverage microfluidic principles but operate at industrially meaningful flow rates (e.g., gallons per minute). The particle size range separated is tunable and tailored by design. Separator prototypes have been developed using metal and plastic 3D printing. With these advanced manufacturing prototypes, separation has been demonstrated in turbulent multicomponent slurry flows up to 90 gpm, thus far, for multiple separator orientations. In sticky nuclear waste simulants, the mesofluidic separator loses <6% of flow in 7 hours and is projected to lose <13% of flow over three years without back flushing or cleaning of the device. In contrast, the dead end filters currently anticipated for TSCR particle separations lose >60% of flow in 7 hours. The mesofluidic separator would operate at low pressures for many DOE waste challenges. This new separation technology has potential for broad applications across the DOE complex, in commercial nuclear reactors, and in cleanup of environmental waste waters.