Analysis of alpha radionuclide in the contaminated water at the torus room of unit #2 reactor of Fukushima Daiichi NPS, 4; Detection of fine particle containing -emitters by SEM-EDX and alpha track

Yomogida, Takumi   ; Ouchi, Kazuki  ; Oka, Toshitaka   ; Kitatsuji, Yoshihiro  ; Koma, Yoshikazu  ; Konno, Katsuhiro*

It has been revealed from the analysis results of ICP-MS and -ray spectrometry that the contaminated water at the torus room of Unit 2 reactor contains -nuclides which were derived from nuclear fuels. To investigate the morphology of these -nuclides, we tried to detect particles containing -nuclides by scanning electron microscopy-X-ray detection (SEM-EDX) and the alpha track method. As a result of SEM-EDX observation, several sub-m to several m size particles containing U were identified. These particles contain elements derived from fuel cladding materials such as Zr, suggesting the possibility that these particles are fine fuel debris. The particles containing alpha emitters were identified by alpha-track method. These particles with few hundred m in diameter were mainly composed of iron oxide, which suggest Pu, Am, Cm were attached to the surface of these particles. These results indicated that the forms of U and other -nuclides were different.