Entwicklung eines Verfahrens zur adsorptiven Abtrennung von Krypton-85

In the final process step of dissolver waste gas purification in a reprocessing facility, the radioactive noble gas Kr-85 is separated by physical separation processes. In the present study investigations have been undertaken into one of the pr inciples under consideration, narrrely adsorption an solids. The experiaents showed that the available gas eixture of air/KrXe can be appropriately separated by chromatography. In principle, the adsorption column is loaded with the waste gas and subsequently regenerated by purging with a carrier gas. A conplete separation of the aaste gas roapanents can thus be achieved. Due to its weak tendency towards adsorption, helium suggests itself as a purge gas. Fine-grained activated charcoals are to be preferred as adsorbinq agents. Among the adsorptive process alternatives studied, one variant in which the adsorber was split into two halves and loaded at - 130 $^\circ$C or - 160 $^\circ$C proved to be particulariy suitable. From the test results it ran be seen that a total of only 0.2 m$^{3}$ of activated charcoal would be required for a coceercial facility with a waste gas throughput of 100 Nm$^{3}$/h. The helium flux required only asmunts to 4 % of the waste gas flow to be purified. If valuable xenon is also to be recovered then this value increases to 7 %. In this rase the quantity of activated charcoal necessary would be 0.28 m$^{3}$. A comparison with alternative process pr inriples indicated thatthe adsorptive concept has advantages with r:espect to process engineering and especially regarding high safety standards in nuclear engineering facilities