Metal frameworks could capture krypton-85 during reprocessing

Copper shows promise: A group of researchers, including members of MIT’s Department of Nuclear Science and Engineering and the Department of Energy’s National Energy and Technology Laboratory, recently published a studyin the journal Nature Communicationsthat evaluated a series of ultra-microporous MOFs with different metal centers, including zinc, cobalt, nickel, and iron. They measured the efficacy and radiation resistance of the materials and found that a copper-containing crystal, SIFSIX-Cu, showed good promise for practical applications of MOFs to spent fuel management.

What’s the benefit? Existing methods for capturing gasses during reprocessing tend to collect oxygen and nitrogen gas, as well as the tiny quantities of krypton, increasing the waste volume, according to MIT. To optimize radiation stability and selective adsorption while also minimizing the volume of waste, the team proposed a two-step treatment process. An initial bed of the material is used to adsorb xenon and carbon dioxide from the effluent gas mixture before it is transferred to a second bed that selectively adsorbs krypton, but not nitrogen or oxygen.