Abstract
Natural radiation is closely related to radiation protection in various aspects. The clarification of its usefulness in the fields of applied nuclear energy and radiation is of importance for their sound utilization. In this paper, the effective dose equivalent due to external natural radiation in Japan was estimated for each prefecture together with its standard deviation, maximum and minimum values based on our nation-wide survey. The average effective dose equivalent due to external natural radiation was 0.59±0.14mSv/y. Using these estimated values, the significance of the results of natural radiation measurements in the fields of nuclear energy application has been discussed in the four aspects: 1) Standard for the dose cognition of artificial radiation, 2) utilization of regional differences of natural radiation dose for the acquisition of public acceptance of artificial radiation, 3) explanation of monitoring results, and 4) epidemiological studies for the analysis of low dose biological effects.
