Basic study on the separation of radioactive cesium from the incinerator ash by using Electrokinetic (EK) method

Otake, Yoshinori; Tambo, Masaki; Kabir, M.*; Inada, Arisa; Fukaya, Hiroyuki; Kida, Takashi

no journal, , 

In March 2011, a large amount of radioactive cesium (hereinafter referred to as Cs) was dispersed over a wide area as a result of Fukushima Daiichi Nuclear Power Plant accident after the devastating earthquake that occurred in Japan. The incinerated ash containing Cs generated by environmental decontamination has become a problem due to lack of storage space. The purpose of this study is to reduce the volume of designated waste that needs to be preserved by removing Cs from incinerator ash using Electrokinetic (EK) method. Two electrodes are placed in the polluted materials (i.e. incinerator ash for this study) with electrolyte solution and a DC voltage is applied in between the electrodes. It can be understood that the Cs ions will move to the cathode side and thus it will be removed from the incinerator ash. At first, a preliminary experiment was conducted with commercially available ash polluted with stable Cs with the concentration ratio 50 mg/kg. We found that more than 80% of stable Cs was separated from the ash with the EK treatment. Then we performed the EK treatment with two types of radioactive contaminated ashes (i.e. fly ash and bottom ash). The radioactive concentration of Cs was about 3,000 Bq/kg to 5,000 Bq/kg for the ashes. We succeeded in the separation of Cs from the ashes. Further works will be carried out with various test conditions, such as, the type of electrolyte and the structure of the test apparatus etc.