title: Temporal variation of dose rate distribution around the Fukushima Daiichi nuclear power station using unmanned helicopter.
abstract: Aerial radiological survey using an unmanned aerial vehicle (UAV) was applied to measurement surface contamination around the Fukushima Daiichi nuclear power station (FDNPS). An unmanned helicopter monitoring system (UHMS) was developed to survey the environmental effect of radioactive cesium scattered as a result of the FDNPS accident. The UHMS was used to monitor the area surrounding the FDNPS six times from 2012 to 2015. Quantitative changes in the radioactivity distribution trend were revealed from the results of these monitoring runs. With this information, we found that the actual reduction of dose rate was faster than the one calculated with radiocesium physical half-life. It is indicated that the attenuation effect of radiation by radiocesium penetration in soil is dominant as for reason of reduction of dose rate.
authors.affiliation: Fukushima Environmental Safety center, Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 45-169, Sukakejo, Kaihama-aza, Haramachi-ku, Minami-soma 975-0036, Japan. Electronic address: sanada.yukihisa@jaea.go.jp.
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Sanada
authors.affiliation: Fukushima Environmental Safety center, Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 45-169, Sukakejo, Kaihama-aza, Haramachi-ku, Minami-soma 975-0036, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Orita
authors.affiliation: Collaborative Laboratories for Advanced Decommissioning Science, Japan Atomic Energy Agency, 2-4 Shirane Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Torii
mesh_terms: D000401:Aircraft / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D062406:Fukushima Nuclear Accident; D007564:Japan; D055848:Nuclear Power Plants; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000379:methods*; D011847:Radioactive Fallout / Q000032:analysis*; D062211:Spatio-Temporal Analysis
chemical_list: D011847:Radioactive Fallout
keywords: Fukushima Daiichi nuclear power station; Radiation measurement; Radioactive cesium; Unmanned aerial vehicle