Decontamination of Radioactive Concrete Waste and Reuse of Aggregate Using Pulsed Power Technology

Concrete debris contaminated with radioactive cesium and other nuclides has been generated by the accident in the Fukushima Dai-ichi nuclear power plant. Moreover, there is concern that a large amount of radioactive concrete waste will be generated by the decommissioning of nuclear power plants in the future. Although conventional techniques are effective in decontaminating concrete with flat surfaces such as floors and walls, it is not clear what techniques to apply for decontaminating radioactive concrete debris. In this study, focusing on a pulsed power discharge technique, fundamental experimental work was carried out and the applicability of the technique to decontaminating radioactive concrete debris associated with the accident in the Fukushima Dai-ichi nuclear power plant was evaluated. The decontamination of concrete by applying the aggregate recycling technique using the pulsed power discharge technique was evaluated by measuring the radioactivity concentration of the divided aggregate and sludge from the contaminated concrete using a Ge-semiconductor detector. It indicated a reduction of the radioactivity concentration in the recovered aggregate and an increase in the radioactivity concentration in the sludge. These findings suggest that the division of the contaminated concrete debris into aggregate and sludge could result in the decontamination and reuse of the aggregate, which would reduce the amount of contaminated concrete debris.