Initial Evaluation of CaSDB MOF Xe and Kr Capacities

Idaho National Laboratory (INL) and Pacific Northwest National Laboratory (PNNL) have been conducting parallel research, as part of the off-Gas Sigma Team, producing and testing sorbents for the selective capture of xenon and krypton from surrogate nuclear fuel reprocessing off-gas streams. Sorbents promising on a laboratory scale are tested further at INL in a system designed to emulate anticipated plant process conditions. This report summarizes INL’s initial testing of CaSDB MOF developed and produced at PNNL. Previous testing of the same base CaSDB MOF material, conducted at INL in 2016, indicated good saturation capacity for xenon, but a low xenon capacity at initial breakthrough. Additionally, the material displayed a propensity to break down into fine powder during use and handling. The current test series looks at the same base material, but with refinements to production and activation techniques. A series of ambient temperature tests were conducted to determine capacities of CaSDB MOF for krypton and xenon at initial breakthrough as well as at saturation. Adsorption tests were run in triplicate at superficial velocities of 21 and 53 cm/min, along with a single test at 373 cm/min. Saturation capacity across all tests was 30 mmol/kg +/- 2, with capacity at initial breakthrough of 8 mmol/kg +/- 1. It should be noted that while the usable portion of the material has a much tighter size distribution than that previously tested, propensity to physically break down into very fine powder with use and handling continues to be problematic. An improved engineered form is recommended prior to further testing