Analysis results on samples obtained inside PCV and relatively high dose materials in Fukushima Daiichi unit 1 to 3

Mizokami, Masato*; Suzuki, Akihiro*; Maeda, Koji  ; Ito, Kenichi*; Sato, Ikken ; Mizokami, Shinya*

Some radioactive material samples were taken inside the PCV of Fukushima Daiichi Units 1-3. TEPCO is working for sample collection, transport, and detailed examinations at hot cells using SEM, TEM and ICP-MS. Uranium-bearing micro-particles were analysed using SEM and Emit was confirmed that particles derived from fuel can be categorized into two groups. One is believed to have been separated from hot corium by hydrodynamic processes, while the other showed characteristics suggesting evaporation from hot corium and condensation afterward. The former particles might have compositional features common to the major part of fuel debris. Both groups possibly cause alpha contamination (actinide behavior) in the reactor building.