Dose rate distribution in the environment and development trend of radiation measurement after Fukushima nuclear power plants accidents

Abstract

  Large-scale environmental monitoring has been implemented several times with collaboration of many organizations, and distributions of dose rates in air and radionuclide deposition on ground have been determined. By analyzing the obtained data, features of contamination conditions and their temporal changes have been clarified. Air dose rates on roads measured by mobile survey were found to decrease much faster than those on undisturbed flat fields.

   From the view of remote operated decontamination in the reactor buildings and remote investigation of inside of Primary Containment Vessels, it is desired that gamma ray imaging and measurement equipment would be lighter, higher resolution and available even in higher background, that radiation measurement equipment would be developed for damaged area by explosion and that Radiation Resistance Guideline would be revised up.