Analysis of particles containing alpha emitters in stagnant water in Fukushima Daiichi Nuclear Power Station's Unit 3 reactor building

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

Particles containing alpha () nuclides were identified from sediment in stagnant water in the Unit 3 reactor building of the Fukushima Dai-ichi Nuclear Power Station (FDiNPS). We analyzed different concentrations of alpha nuclides samples collected at two sampling sites, torus room and Main steam isolation valve (MSIV) room. Most of the -nuclides in the stagnant water samples of the torus room and the MSIV room were present in particle fractions larger than 10 m. We detected uranium-bearing particles in m-size by scanning electron microscopy-energy dispersive X-Ray (SEM-EDX) observation. Other short lived -nuclides were detected by alpha track detection. The -nuclide-containing particles with several tens to several hundred m in size were mainly comprised iron (Fe) by SEM-EDX analysis. This study clarifies that the morphologies of U and other -nuclides in the sediment of stagnant water in the FDiNPS's Unit 3 reactor building.