Comparative study of radiation mapping technologies for nuclear disaster assessment

Ochi, Kotaro   ; Barker, E.*; Nakama, Shigeo ; Gleizes, M.*; Manach, E.*; Vincent, F.*; Sanada, Yukihisa   

There are no clear criteria for standardizing mapping techniques for ambient dose equivalent rate (air dose rate) distributions in different countries. Thus, in this study, manborne, carborne, and airborne radiation surveys were conducted jointly by the Japan Atomic Energy Agency and the French Institute for Radiological Protection and Nuclear Safety in the vicinity of the Fukushima Daiichi Nuclear Power Station to confirm the effectiveness of each organization's monitoring methods. For example, in the manborne survey, the discrepancy between the air dose rates measured by the two institutions was observed depending on whether or not the contribution from radionuclides with different gamma-ray energies was considered when converting the count rates obtained by the detectors to air dose rates. As in this study, comparing mapping techniques among various countries and providing feedback to each other should help to improve the accuracy of zoning scenarios after nuclear accidents.