The research group of the University of Tokyo, in collaboration with the Agricultural and Food Industry Technology Research Organization and the Japan Atomic Energy Agency, heats the radioactive fine particles scattered from the nuclear reactor to a high temperature in the Fukushima nuclear accident, and the radioactive cesium contained in the fine particles is removed. I found that I would let go.It can be an important contribution to the method of treating decontamination waste.
Recent research has revealed that some of the radioactive cesium released in the Fukushima nuclear accident is contained in glass particles of a few microns or less that are thought to have scattered from the reactor.Since these fine particles are easily suspended in the atmosphere and the radioactivity per particle is considerably higher than that of soil particles adsorbing radioactive cesium, there is a concern about the influence of radiation on the periphery of the particles.In addition, the behavior of radioactive fine particles during incineration was unknown.
This time, the research group investigated changes in radioactivity and structure due to heating of these radioactive fine particles.As a result, it was found that the radioactivity of the radioactive fine particles gradually decreased at 600 ° C or higher, and was almost lost at 900 to 1000 ° C.The fine particles did not change in morphology before and after heating, but the cesium, potassium, and chlorine that were initially contained had disappeared, and it is considered that the fine particles were desorbed from the glass into the atmosphere.It was also found that when the radioactive fine particles were mixed with soil and heated, the radioactive cesium desorbed from the fine particles was adsorbed by the surrounding soil particles.
This suggests the use of sufficiently high temperature conditions and filters when incinerating decontamination waste and the like in order to reduce the influence of radiation due to the scattering of fine particles from incineration ash and the like.This result clarifies the important properties of minute radioactive substances whose environmental dynamics were unknown, and is expected to contribute to future nuclear accident pollution control measures.
Paper information:[Scientific Reports] Loss of radioactivity in radiocesium-bearing microparticles emitted from the Fukushima Dai-ichi nuclear power plant by heating