Development of decontamination techniques at waste dismantling facility of Power Reactor and Nuclear Fuel Development Corporation, (1)

Various decontamination techniques have been developed and demonstrated at a solid waste dismantling facility in the Oarai Engineering Center of Power Reactor and Nuclear Fuel Development Corporation with the aim of promoting full-scale decommissioning of nuclear fuel cycle plants and other facilities. Of the various decontamination techniques, the report focuses on ice blasting and electrolytic polishing for decontamination. Ice blasting is based on the abrasive decontamination process, which use a high pressure fluid to throw polishing material such as glass or alumina against contaminated surface. Particles of ice or dry ice or a mixture of them are used as blasting material to reduce the generation of secondary waste. Pressed air is used as fluid medium for carrying blasting particles. The other technique, electrolytic polishing, is basically the same as that widely used for metal surface treatment. When positive electric charges are supplied to metal in conductive electrolytic solution, its surface is dissolved into ions and contaminant nuclides are removed. (N.K.)