Abstract: Disclosed is a method and device for collecting particulate contaminants removed using a CO2 decontamination medium from an early step of a decontamination process. The device removes particulate contaminants from a contaminated subject by a decontamination stream, and simultaneously forms another stream for collecting such contaminants into a collecting filter, thus preventing such contaminants from diffusing into the atmosphere. The device forms streams between the nozzles and the surface of the contaminated subject to readily move the nozzles along the surface of the subject without frictional resistance, to reduce the sense of fatigue of the operator.

Abstract: Disclosed is a method and device for collecting particulate contaminants removed using a CO2 decontamination medium from an early step of a decontamination process. The device removes particulate contaminants from a contaminated subject by a decontamination stream, and simultaneously forms another stream for collecting such contaminants into a collecting filter, thus preventing such contaminants from diffusing into the atmosphere. The device forms streams between the nozzles and the surface of the contaminated subject to readily move the nozzles along the surface of the subject without frictional resistance, to reduce the sense of fatigue of the operator.

Abstract: A method and an apparatus for electrokinetically decontaminating the soil contained in a radioactive waste drum are disclosed. The radioactively contaminated soil is put into drums, and the drums are carried to a temporary storage or to a disposal site. If the extremely low level radioactive soil is decontaminated rather than carrying the soil to the temporary storage or to a disposal site, and if the decontaminated soil is returned to the nature, then the limited storage capacity can be saved. Further, if a high level radioactive soil is treated to a low level one, and if thus a low level radioactive soil is stored in a storage, then the safety is improved. In the present invention, electrodes are buried into the contaminated soil contained in a radioactive waste drum, and a dc current is supplied, so that the radioactive nuclide and impurities can be removed by the electroosmosis and the electromigration.

Abstract: Novel calix[4]arene dibenzo crown ethers useful to selectively extract cesium are represented by the formula: wherein R is a C.sub.1 -C.sub.10 normal alkyl, a phenyl or a methoxyphenyl, R' is hydrogen, p-tert-butyl or a C.sub.1 -C.sub.10 normal alkyl, R" is a C.sub.1 -C.sub.10 normal alkyl, and n is an integer of 0-2. The novel compound is prepared at high yields by introduction of benzene rings into the crown ether ring of calix[4]arene crown-6-ether. The calix[4]arene dibenzo crown ethers are superior in selective absorptivity for cesium ions by virtue of their 1,3-alternate conformational structure and thus, can be used as selective extractants able to separate cesium ions at a high efficiency.

Abstract: A wet recycling method for impregnated active carbon used to remove radioactive organic iodide in a nuclear power plant by extracting impregnated substance and radioactive organic iodide from the used impregnated active carbon with an acetonitrile solution and reproducing active carbon to be used in preparing impregnated active carbon, the filtered extractive solution being distilled to obtain pure acetonitrile for the use purpose as an extractive solution, the impregnated substance and radioactive organic iodide extracted in a small amount of solid, thus reducing the volume of the waste impregnated active carbon greatly to decrease solid waste material and at the same time recycle materials.