Radiation monitoring using manned helicopter around the Nuclear Power Station in the fiscal year 2018 (Contract research)

Futemma, Akira; Sanada, Yukihisa   ; Ishizaki, Azusa  ; Komiya, Tomokazu; Iwai, Takeyuki*; Seguchi, Eisaku*; Matsunaga, Yuki*; Kawabata, Tomoki*; Haginoya, Masashi*; Hiraga, Shogo*; Sato, Kazuhiko*; Sato, Yoshiharu; Urabe, Yoshimi*; Shimada, Kazumasa ; Mori, Airi; Hirouchi, Jun ; Hiraoka, Hirokazu  ; Kudo, Tamotsu 

By the nuclear disaster of Fukushima Daiichi Nuclear Power Station (FDNPS), Tokyo Electric Power Company (TEPCO), caused by the Great East Japan Earthquake and the following tsunami on March 11, 2011, a large amount of radioactive material was released from the FDNPS. After the nuclear disaster, airborne radiation monitoring using manned helicopter has been conducted around FDNPS. The results in the fiscal 2018 were summarized in this report. Discrimination method of gamma rays from Rn-progenies was also utilized to evaluate their effect on aerial radiation monitoring. In addition, analysis taken topographical effects into consideration was applied to previous results of airborne monitoring to improve the precision of conventional method.