Method of recovering krypton and xenon nuclides from waste gases

A method of recovering nuclides from waste gases, comprising the steps of conveying a stream of waste gas which includes krypton and xenon nuclides through adsorbing means containing a bed of adsorbent which is at a predetermined pressure so as to adsorb nuclides from said waste gas, said waste gas also including a carrier gas component constituting the major portion thereof and being conveyed through said bed in a predetermined direction;

• interrupting said conveying step when the concentration of krypton nuclides in the gas escaping from said bed reaches substantially a predetermined value;
• reducing the pressure in said bed to between approximately 10 and 300 torr so as to partially evacuate said bed and obtain a desorption gas, said pressure-reducing step being carried out in such a manner that evacuation of said desorption gas from said bed occurs concurrent with the flow of said waste gas;
• rinsing said bed with rinsing fluid so as to desorb nuclides from said bed and obtain product fluid enriched in nuclides, said rinsing step being initiated before the concentration of krypton nuclides in said desorption was substantially exceeds the concentration of krypton nuclides in said waste gas, and said rinsing fluid being conveyed through said bed countercurrent to the flow of said waste gas and at pressures between approximately 10 and 400 torr;
• raising the pressure in said bed to substantially said predetermined pressure prior to repeating said conveying step by introducing into said bed a gaseous substance having a composition substantially the same as that of said carrier gas component and which is substantially free of nuclides;
• and admitting at least a portion of said desorption gas into an adsorbent for the adsorption of nuclides therefrom.