The evacuated zone is quite typical of Northeast Japan, i.e., comprising a narrow coastal plain and valleys leading into a spine of densely wooded mountains. Along the coast and in the plain, the population density is relatively high with agriculture being an important industry. In the more mountainous areas, the population is mainly confined to narrow valleys although, even here, agriculture is important, as is tourism.
The locations of the sites selected for the decontamination pilot projects, specific constituents and features requiring clean-up, the levels of contamination and project site grouping are summarised in Figure 1 and Table 1. As can be seen, these are representative of the challenges that will be faced in the regional remediation and allow different approaches to remediation to be compared. Further, the locations include both urban and rural areas in different types of terrain (mountains, hills and plain).
After a number of general contractors were asked to submit proposals for remediation work (including planning and evaluation), three consortiums were selected by the Japanese Atomic Energy Agency (JAEA) to undertake the task: Obayashi Joint Venture (JV), the Taisei JV and the Kajima JV. The locations of the sites selected on the basis of discussion with the Municipalities involved are illustrated in Figure 1.
Initially 12 municipalities within the evacuated areas were selected for targeted remediation work. However, it was not possible to agree locations in one case (Futaba). The sizes of the decontamination areas were approximately 20 ha per municipality. As noted above, the specific features requiring clean-up, and site groupings are summarised in Table 1. The groups basically represent more northerly, central and southern locations, with a little redistribution between the last two to improve the balance of the distribution of levels of contamination in each group. Each of the three JVs was assigned one of these groups. JVs implemented their proposed technological activities and JAEA managed, supervised and evaluated the overall program. Documentation of the decontamination pilot projects has been published in Japanese (http://www.jaea.go.jp/fukushima/kankyoanzen/guideline_report.html; http://www.jaea.go.jp/fukushima/kankyoanzen/d-model_report.html).