Detection and analysis of particles containing alpha-emitters in stagnant water at torus room of Fukushima Dai-ichi Nuclear Power Station's Unit 2 reactor

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

As part of the decommissioning work of the Fukushima Daiichi Nuclear Power Plant (1F), disposal of stagnant water existing in the basement of the turbine building is underway. Higher concentrations of alpha nuclides have been detected in the stagnant water in the reactor building than in the downstream buildings. It is necessary to consider technology to effectively remove -nuclides to proceed with the disposal of the stagnant water in the reactor buildings. We focused on particulate -nuclides in the stagnant water in the torus room of Unit 2, and analyzed and investigated their particle size, chemical form, etc to understand morphology of -nuclides. We detected particles containing -nuclides by SEM-EDX and alpha-track detection. The results showed that U is in particle form, ranging from a few hundred nm to a few m. Other -nuclides (Pu, Am, and Cm) were distributed on iron oxide particles.