Abstract: An improved method and apparatus for regeneration and reuse of He--N.sub.2 --CO.sub.2 mixed gas for carbon dioxide gas laser. The laser gas after use is contacted with a noble metal catalyst (for example, Pt--Al.sub.2 O.sub.3) at a temperature of 200.degree.-300.degree. C. to react CO and O.sub.2 formed by laser discharge so as to form CO.sub.2. A suitable quantity of moisture in the contained laser gas causes steam-reforming reaction of H.sub.2 O and CO, and reaction of H.sub.2 and O.sub.2 following thereto, and continuous operation over a long period is thus possible. Poisoning of the catalyst by NO.sub.x is suppressed at this relatively high temperature of reaction. Activity of the catalyst, when decreased, may be recovered by reactivation by passing a reactivating gas consisting of carbon monoxide, oxygen and helium through the catalyst bed at a temperature of 400.degree. to 500.degree. C.

Abstract: A method of treating radioactive waste water generated during chemical decontamination at nuclear power facilities is disclosed. Decontaminating agents, with organic acids, and normally containing inhibitors and surface active agents, are decomposed by oxidation using hydrogen peroxide, at a temperature of 60.degree.-90.degree. C., in the presence of copper ions, or copper ions and iron ions, as catalysts.

Abstract: Radioactive organic wastes such as anion-exchange resins, chelate resins and organic filter sludges are readily oxidized by reacting hydrozen peroxide in an aqueous medium in the presence of iron-ions or both iron-ions and cation-exchange resin to be decomposed to carbon dioxide and water. Contact between the wastes to be decomposed and hydrogen peroxide is preferably conducted by continuously feeding hydrogen peroxide or both hydrogen peroxide and the wastes to be decomposed to the reaction zone.