On the data processing related to environmental radioactivity

The monitoring and measurement of environmental radioactivity have been undertaken by many organizations in Japan. The Japan Chemical Analysis Center has been entrusted by the government to gather and edit these measured results. The computer processing of these data started in 1978, and it is expected that by the end of fiscal year 1984, all fallout data since 1957 and all radioactivity monitoring data since 1969 can be registered. The computer programs for processing the data such as the output of tables and figures have also been developed, and the edition of reports has been made. The replacement of the computer and the development of a new processing system capable of handing Kanji (Japanese-Chinese characters) are now scheduled. This document outlines the data system such as the quality, quantity and origin of the measured data and the frequency of report publication. Some results of the analysis of fallout nuclides, space gamma dose rate and the total β-activity in rain are presented. The effects of the nuclear explosion tests in China are very obvious in these figures. A chronological table of the explosion tests in China is also presented. The different effects of time lag at the different places of measurement are also seen. The effects of the presence of nuclear power plants were also investigated at some sites of the plants, but no discernible effect was observed. (Aoki, K.)