Why did so few refugees return to the Fukushima fallout-impacted region after remediation? An interdisciplinary case study from Iitate village, Japan

International audienceLarge volumes of radionuclides were deposited on the soils in Northeastern Japan after the accident at the Fukushima Dai-ichi nuclear Power Plant (FDNPP) in March 2011. The village of Iitate, with a population of 6544 inhabitants in early 2011, was located in the main radioactive plume. Its population was evacuated between 2011 and 2017, when the town reopened after decontamination was completed in some cultivated and residential areas. This situation is unprecedented in history. Even around Chernobyl, access to the most contaminated area has remained forbidden until today. This manuscript compiles measurements of radiation dose rates and sediment radioactive contamination, socioeconomic statistics, and reports the results of interviews conducted among refugees since 2011. Despite this reopening, which was presented as desirable by the authorities, less than ten percent of the original population-almost all of them over 70 years oldhad returned to live in the village by January 2022. An analysis of the evolution of the population shows that it is now declining again. When the village was evacuated in 2011, most of the families that used to live with three generations under the same roof were often separated. The majority of the inhabitants took refuge in neighbouring municipalities, and many lived in temporary housing sites with a strong feeling of promiscuity. This study shows the difficulty for the majority of villagers who had never heard of Becquerels before the accident in 2011 to return to a very different environment with forests remaining contaminated and major landscape transformations having occurred after several years of abandonment and through the remediation process itself. Before 2011, forests and cropland were the main land uses in the village, and the local authorities promoted a model of eco-village. While decontamination has been effective in limiting the dispersion of radionuclides across the landscape, it did not affect the large stock of radionuclides stored in forests that cover ∼80% of the surface area. Moreover, the lack of facilities and public services remains problematic for an elderly population that has a limited mobility to travel to nearby towns to find the necessities of everyday life. This study provides a benchmark for comparison with the evolution of the seven other municipalities located nearby FDNPP that are being reopened to settlement. This research, which shows the situation after a remediation tentative, will provide a unique reference in post-accident management