Characterization of carbonate slurry generated from multi-radionuclide removal system in Fukushima Daiichi Nuclear Power Station

Hinai, Hiroshi; Arai, Yoichi  ; Fukuda, Yuhei; Kurosawa, Akira; Koma, Yoshikazu  ; Shibata, Atsuhiro  ; Nomura, Kazunori  

Multi-Radionuclide Removal System (MRRS) has been operating to decontaminate the contaminated water in Fukushima Daiichi Nuclear Power Station. MRRS consist of pretreatment facilities (Iron coprecipitation treatment facility and Carbonate precipitation treatment facility) and adsorption towers. This system is able to remove most of the radioactive materials except Tritium. However, Associated with a this process, the secondary radioactive wastes (slurry, spent adsorbent) were generated and stored temporary in the High Integrity Container (HIC). It is necessary to various properties investigation for the inventory evaluation and future disposal. Therefore, the carbonate slurry samples were transported from Fukushima Daiichi Nuclear Power Station to our laboratories in Tokai-mura and analyzed. High concentration of Sr-90 (1.310 [Bq/cm]) was determined in the sample by the radioactive measurement, it is inferred that the contaminated water has been concentrate. And small amount of -ray emitting nuclides were determined. As the result of ICP-AES, it is estimated that most of slurry occupy CaCO and Mg(OH). These obtained data showed that decontamination system is operating normally. Also, the particle size of the slurry was analyzed by image analyzing method. The particles of slurry was found to have a median particle diameter of several m.