Nuclear decontaminationLessons Learnt from Fukushima Soil Decontamination

Following the accident at the Fukushima nuclear power plant in March 2011, the Japanese authorities decided to carry out major decontamination works in the affected area, which covers more than 9,000 km². On 12 December 2019, with most of this work having been completed, the scientific journal Soil of the European Geosciences Union (EGU) is publishing a synthesis of approximately sixty scientific publications that together provide an overview of the decontamination strategies used and their effectiveness, with a focus on radiocesium. This work is the result of an international collaboration led by Olivier Evrard, researcher at the Laboratoire des Sciences du Climat et de l’Environnement [Laboratory of Climate and Environmental Sciences] (LSCE – CEA/CNRS/UVSQ, Université Paris Saclay).

The EGU says that soil decontamination, which began in 2013 following the accident at the Fukushima Dai-ichi nuclear power plant, has now been nearly completed in the priority areas identified¹. Indeed, areas that are difficult to access have not yet been decontaminated, such as the municipalities located in the immediate vicinity of the nuclear power plant. Olivier Evrard, a researcher at the Laboratory of Climate and Environmental Sciences and coordinator of the study (CEA/CNRS/UVSQ), in collaboration with Patrick Laceby of Alberta Environment and Parks (Canada) and Atsushi Nakao of Kyoto Prefecture University (Japan), compiled the results of approximately sixty scientific studies published on the topic.

This synthesis focuses mainly on the fate of radioactive cesium in the environment because this radioisotope was emitted in large quantities during the accident, contaminating an area of more than 9,000 km². In addition, since one of the cesium isotopes (¹³⁷Cs) has a half-life of thirty years, it constitutes the highest risk to the local population in the medium and long term, as it can be estimated that in the absence of decontamination it will remain in the environment for around three centuries. “The feedback on decontamination processes following the Fukushima nuclear accident is unprecedented,” according to Olivier Evrard, “because it is the first time that such a major clean-up effort has been made following a nuclear accident. The Fukushima accident gives us valuable insights into the effectiveness of decontamination techniques, particularly for removing cesium from the environment.”