A comparison of remediation after the Chernobyl and Fukushima Daiichi accidents

Remediation of terrestrial areas has been widely applied to areas contaminated by nuclear accidents, and, in particular, after NPP accidents at Windscale [UK], Chernobyl [Former USSR] and Fukushima Daiichi [Japan]. Radioiodine and radiocaesium isotopes were important dose-forming radionuclides for all of these accidents. Each of the contaminated areas associated with these accidents differed, to varying extents, in terms of contamination levels, environmental characteristics and social and cultural issues. I will compare remediation of terrestrial areas for two of these accidents, Chernobyl and Fukushima Daiichi. The comparison considers: (1) the challenge addressed in terms of the release, environmental pathways of the radionuclides and the radiological consequences for the public, (2) the policy and planning approaches adopted (3) the strategies used to remediate contaminated areas, (4) the implementation of remediation and (5) the outcomes. The comparison utilises the IAEA's Chernobyl forum report with further recent information for Chernobyl based on a series of papers led by Jacob and Fesenko. For the Fukushima Daiichi accident key documents include many reports, papers and web sites providing information from Japanese organisations, UNSCEAR reports and IAEA reports namely (1) the Follow-up International Mission on remediation of large contaminated areas (2) an International Experts Meeting on Decommissioning and Remediation (3) the recent IAEA Fukushima report and associated annexes. Some key differences between remediation after the Chernobyl and Fukushima Daiichi accidents will be discussed including the: 1. relative importance of : a. environmental factors such as land use and soil type; b. different agricultural production systems for internal dose; c. the economic situation of the population in the affected area and their life-style; d. the time of year when radionuclides were deposited. 2. use of predicted annual effective doses to determine the areas designated for remediation 3. derivation and implementation of criteria for remediation 4. extent of remediation focused on internal dose (Chernobyl) and on external dose after Fukushima 5. selection of remediation measures applied 6. rate, extent and duration of remediation activities 7. remediation of evacuated areas (author)