Alpha radioactivity measurement based on ionized air transportation technology

Aoyama, Yoshio ; Miyamoto, Yasuaki ; Yamaguchi, Hiromi ; Naito, Susumu*; Sano, Akira*; Izumi, Mikio*; Sumida, Akio*; Maekawa, Tatsuyuki*; Sato, Mitsuyoshi*; Nambu, Kenichi*; Takahashi, Hiroyuki*; Oda, Akinori*

Radioactive waste contaminated by Uranium has been accumulated in front-end facilities of the nuclear fuel cycle. The purpose of the present project is to develop the practical and highly efficient measurement system, which solves the above-mentioned requirements based on the innovative concept of indirect alpha radioactivity measurement using ionized air stream transportation. The ionized air by alpha particles near the waste is peeled and transported into the ion sensor by controlling air stream in the measurement system. In order to give the actual solution for this indirect measurement concept, we have to clarify various basic physics concerning with radiation ionizing process in the air, ion reaction process in the air, ion transportation process by the turbulent air flow, and measurement process in the ion sensor. For this purpose, we have to develop various analytical simulation technologies for predicting ion behavior as well as direct measurement technologies of ion spatial distribution. The final target of the project is to establish the practical and verified clearance confirmation technology based on the above-mentioned physical and technological knowledge.