Study on the radioactive contamination in the reactor building unit #4 of Fukushima Daiichi NPS

福島第一原子力発電所4号機原子炉建屋内における放射性核種による汚染の考察

二田 郁子; 比内 浩; 柴田 淳広  ; 野村 和則  ; 大木 恵一; 駒 義和  

Nitta, Ayako; Hinai, Hiroshi; Shibata, Atsuhiro; Nomura, Kazunori; Oki, Keiichi; Koma, Yoshikazu

By the accident of Fukushima Daiichi NPS (1F), large amount of radioactive wastes have been generated such as rubbles, soil, and vegetation. To characterize the wastes, samples of them have been collected and analyzed by TEPCO and JAEA. In the present study, radioactive contamination in the reactor building (R/B) unit #4 was compared with those in the R/B units #1, #2 and #3 by means of the analytical data of concrete samples collected inside the R/Bs. Radioactivity concentration ratio of various nuclides against Cs-137 in the R/B unit #4 appeared greater than those in other R/Bs because of low radioactivity concentration of Cs-137 in the R/B unit #4. It is considered that contamination process is different between the R/B unit #4 and other units.