Adsorption of krypton on adsorbents at cryogenic temperatures

Most of 85Kr in atmosphere is released from anthropogenic sources such as tests of nuclear weapons and nuclear reactors. As a chemically inert gas with a long half-life, 85Kr will continue to accumulate in the environment. Thus, it is necessary to monitor the atmospheric 85Kr concentrations. In this study, the authors conducted a screening test of several adsorbents to search for suitable adsorbents for adsorption of Kr at under nitrogen atmosphere, which is used for the monitoring system of 85Kr. A screening test was carried out by focusing on adsorption characteristics at a cryogenic temperature. With regard to adsorbents selected in the screening test, more detailed adsorption characteristics were examined. As a result, it was found that carbon based adsorbents have better performance for adsorption of Kr and that the Ambersorb 572 adsorbent has the largest adsorption capacity. It was also found that the adsorption capacity of non-carbon based adsorbents is much lower than that of carbon-based adsorbents. (author)