[en] Process performance and reliability have been demonstrated on an engineering scale with 10 years of pilot plant operation, including extended testing with ⁸⁵Kr, ¹³³Xe, and ¹³¹I. The selective absorption process is based on exploitation of solubility differences which exist among the noble gases and other gas-phase constituents in a fluorcarbon solvent. Much information now exists on the solubilities of various components in CC1₂F₂, which is the reference solvent, and on other aspects of this fluorocarbon system. The effects of carrier gas coabsorption and solvent vaporization/condensation on noble gas mass transfer inside the absorption and stripping zones have been determined. The effects of column size on mass transfer have also been measured and rigorous engineering models have been derived for the process hardware. Many improvements and simplifications have been made to the original version of the process, and depending upon the separation task, a variety of system configurations is possible. The selective absorption process is applicable to essentially all types of nuclear facilities, and several gas cleanup tasks have been considered. One of these, post-accident reactor cleanup, is described