Development of the equipment for measuring specific activities of gamma-emitting radionuclides in soil

Decontamination works following the reactor accident of Fukushima Daiichi Nuclear Power Station are producing large amount of radioactive wastes in the form of soils, grass and trees, dead branch and leaves, and mud. In the interim storage facilities for receiving these radioactive wastes, the wastes are divided in two groups according to their radioactivity (I: below 8,000 Bq/kg and II: higher than 8,000 Bq/kg) to manage safely until the final storage facilities are constructed. Fuji Denki Co. and Shimizu Kensetsu Co. developed a facility that can measure large amount of radioactivity concentrations batch-wisely or continuously and also automatically dividing the wastes into two groups I and II. The facility can measure the activity within 20% precision. (S. Ohno)