Decommissioning Process Processing/Disposal/Environment Remediation (including Wastes containing Alpha Nuclides originating from Fuels)
Investigation Subject Environmental remediation
Issue Site decontamination and dose rate reduction
① Decontamination and reducing the dose rate
Desired state and reasons for it
It is desirable to develop more efficient, effective, and economical decontamination technologies considering the environmental dynamics of radioactive materials, by accurately and promptly understanding the contamination status and dose rate at the site.
It is desirable that site decontamination is promoted by technologies such as soil clean-up and improvement and asphalt pavement clean-up, and that site dose rates is reduced accordingly.
Current state against ideal
As analytical research on environmental dynamics of radioactive cesium outside of the site, it has been developed and organized river-basin dynamics model, river system dynamics model, dose rate evaluation model, depth migration model and evaluation model of the migration to agricultural, forestry, and marine products. By selecting or flexibly combining these models according to the purpose, it has been implemented the prediction of the distribution of radioactive cesium and air dose rates over the medium and long term, the evaluation of the amount of radioactive cesium outflowed from rivers to the sea, the evaluation of the behavior of radioactive cesium in rivers and dam lakes during heavy rainfall, and the evaluation of the influence of the dynamics of radioactive cesium in the environment on the concentration of radioactive cesium in agricultural, forestry, and marine products.
In off-site analytical research on the environmental dynamics of radioactive cesium, we have developed and maintained a watershed dynamics model, a water area dynamics model, a dose rate assessment model, a depth transfer model, and an assessment model for the transfer of agricultural, forestry, and fishery products. The models are used to predict the distribution of radioactive cesium and air dose rates over the medium to long term, evaluate the amount of radioactive cesium discharged from rivers into the sea, evaluate the behavior of radioactive cesium in rivers and dam lakes during heavy rainfall, and evaluate the effect of the dynamics of radioactive cesium in the environment on the concentration of radioactive cesium in agricultural, forestry, and marine products.
It is necessary to investigate how to combine decontamination technologies in order to reduce the site dose rate.
Issues to be resolved
It is necessary to continue analytical studies and impact assessments on various dynamics, such as environmental dynamics and also advance to be able to cope with the special environment of the Fukushima NPP premises. Furthermore, it is necessary to consider the changes that have occurred over time since the accident.
With regard to the reduction of site dose rates, it is necessary to investigate the perspective of efficiency, effectiveness, and economy as issues.
Please note that this English text is a provisional translation of the Japanese original.