United States – Using a newly-developed computer model, US scientists have discovered a material that could help to recycle nuclear fuel by capturing gases released during reprocessing. The material, a metal-organic framework (MOF) with the designation SBMOF-1, can remove radioactive krypton and xenon at ambient temperatures.
‘This is a great example of computer-inspired material discovery,’ comments Praveen Thallapally, one of the researchers and associated with the US Department of Energy’s Pacific Northwest National Laboratory. ‘Usually, the experimental results are more realistic than computational ones. But this time, the computer modelling showed us something the experiments weren’t telling us.’
To capture emitted radioactive gases such as krypton and xenon, entire gas streams are brought to temperatures below 0°C, which is both costly and energy-intensive. This study looked at MOFs as they can trap these gases without the use of cryogenics. Containing small pores that can hold one molecule of a gas, MOFs can be used to selectively adsorb specific gases.
Maciej Haranczyk and Berend Smit from Lawrence Berkeley National Laboratory screened 125 000 possible MOFs to find one suitable for particular filtration purposes. SBMOF-1 possesses a pore size similar to xenon and was tested with a variety of gases including xenon, krypton, oxygen, helium, nitrogen and carbon dioxide. All other gases apart from xenon were able to pass through the material.
Source: Nature Communications.