Seabed sediments were collected off the coast of Niigata Prefecture and Yamagata Prefecture and radioactivity was measured to identify the migration pathway of radioactive caesium from the Fukushima Dai-ichi Nuclear Power Plant. 134Cs from the Fukushima Dai-ichi Nuclear Power Plant was detected in seabed sediment from offshore Sakata and Kamo (0.16±0.03 to 0.68±0.02 Bq/kg), but was not detected in seabed sediment from offshore Naoetsu. The results suggest that the potential source is the region northeast of Naoetsu to Sakata, including the Agano and Mogami Rivers.
Teaching exercises for radiation education to evaluate radioactivity concentration in environmental samples with certified reference materials was developed. This enables us to evaluate the radioactivity concentration at low level such as a standard of radiocesium in general food. Master course students at Tokyo Gakugei University were tentatively trained with the above teaching exercises, where they mostly acquired not only a deeper understanding of soil contamination and food safety but also gaining objective perspectives for radiation and nuclear disaster. It is demonstrated that the present teaching materials are of usefulness in the advanced curriculum of radiation education in teacher-training universities.
As for the Fukushima Dai-ichi Nuclear Power Plant Accident occurred in March, 2011, studies on characterization of fuel debris and movement of nuclear fuel materials, fission products and minor actinides in reactor, the evaluation of environmental contamination were introduced in relation with the radioactive waste managements. Furthermore, the situation of the back-end research in the fuel cycle and necessity of the facilities for nuclear materials and radioisotopes in nuclear engineering field were also discussed.
Institute of Nuclear Study was unified into High Energy Research Organization in 1997 and finished its role. For decommissioning of whole facility, decontamination of radiation facility and closing of control areas and removal of hazardous substance were carried out. The site has been used as the park of Nishi-Tokyo City. Here we described removal of radioactive and hazardous substance contamination and meetings with local residents,