[2K01-04] Contaminated Concrete

[2K03] Investigation on mass balance of volume reduction process for fly ash produced in thermal treatment of radio-actively contaminated off-site incineration residue

*Kenichi Arima¹, Masahiro Osako¹, shunji Oda², Hisao Tohma², Keisuke Imai² (1. National Institute of Environmental Studies, 2. Japan Environmental Storage & Safety Corporation)

Keywords:radiocesium, thermal treatment, fly ash, volume reduction, mass balance

For off-site incineration residue contaminated by radio-cesium from Fukushima Daiichi Nuclear Power Station accident, thermal treatment has been carried out from March 2020. Its main product is molten slag with a low concentration of radiation, which is planned to be reused. On the other hand, its by-product is highly radioactive fly ash, the treatment and final disposal of which is the subject of various studies. Its representative treatment is leaching radio-cesium into water by washing, adsorbing selectively the radio-cesium by adsorbent and stabilizing the used adsorbent with solidifier such as cement. In this study, basic experiment of fly ash washing was carried out and based on the results, mass balance of volume reduction process for fly ash was calculated and mass and radioactivity of the products were evaluated.