Status of long-term assessment of transport of radioactive contaminant in the environment of Fukushima (Fukushima-TRACE project)

Sato, Haruo

The accident at the TEPCO Fukushima Dai-ichi Nuclear Power Plant in March 2011, led to the release of volatile radionuclides which were deposited on the surrounding environment (soils, forests, residential land, etc.) around the Fukushima Pref. Radiocaesium is now the main contributor to radiological dose and therefore understanding its transport behaviour is essential to assess potential doses in the future. Based on this situation, JAEA began a research project entitled the "Long-Term Assessment of Transport of Radioactive Contaminant in the Environment of Fukushima" (F-TRACE) in November 2012. This project aims at transport process of soil particles and plants etc. sorbed radiocaesium by water-flow and winds, and has 3 objectives; (1) to elucidate the transport behaviour of radiocaesium from contaminated mountain forests, through the biosphere to lacustrine and coastal sinks, (2) to develop an appropriate dose evaluation system, and (3) to implement a comprehensive system for predicting radiocaesium transport and the impact of various counter-measures to limit resultant doses. The research programme includes 9 study topics; forest ecosystems, the fluvial environment, the lacustrine environment, the estuarine environment, laboratory investigations of Cs transport, model analysis (simulation of Cs transport), lichen biomonitors, development of techniques to restrict Cs transport, and follow-up monitoring. The field work has been carried out for mainly 5 rivers flowing into the Pacific Ocean since December 2012. Many data were obtained in the field work to date, and status of the F-TRACE Project in addition to its overview will be presented in the meeting.