Schematic of the concept of the two-bed technique for krypton 85 removal from spent nuclear fuel. Source: Sameh K. Elsaidi et al.Schematic of the concept of the two-bed technique for krypton 85 removal from spent nuclear fuel. Source: Sameh K. Elsaidi et al.

While nuclear power offers a greenhouse gas-emissions free route to electric power production, the fuel reprocessing phase of the nuclear fuel cycle releases volatile radionuclides. The high-cost, complex cryogenic separation systems used to capture these constituents might be replaced with a method based on radiation-resistant metal organic framework (MOF) materials developed by an international research team..

The ultra microporous material incorporating zinc, copper, nickel, cobalt or iron, previously demonstrated to selectively remove carbon dioxide from air, was tested in a two-bed breakthrough setup. Two columns were filled by adsorbent material tuned to provide preferential adsorption of xenon, krypton 85, nitrogen, and CO2 gases. Xenon is captured in the first step while krypton 85 is collected in the second, enabling its separation into a high purity gas.

Radiation stability of the MOF was signaled by the effective preferential adsorption of xenon and CO2 over krypton, and the preferential adsorption of krypton over nitrogen and oxygen.

The noble gas capture technique described in Nature Communications can translate into reductions in the size of the equipment needed as well as a reduced volume of waste that must be stored until the radioactivity decays. Scientists from the University of California Berkeley, University of Pittsburgh, MIT, Nuclear Materials Authority (Egypt), University of South Florida, University of Tampa, U.S. Department of Energy (DOE) National Energy and Technology Laboratory and DOE Pacific Northwest National Laboratory contributed to this research.

To contact the author of this article, email shimmelstein@globalspec.com