W. Thu Zar et al.: Radioprotection 2025, 60( 4), 344 – 353 345
leurs aînés, qui privilégient les grandes conférences. Compte tenu de la complexité de la situation actuelle, ces résultats soulèvent une série de défis quant à la mise en œuvre éventuelle du processus de co-expertise au sein de la population actuelle de Futaba.
Mots-clés: accident de Fukushima / ville de Futaba / préoccupations sanitaires / processus de co-expertise / communication sur les risques
1 Introduction
Futaba Town, the last municipality in Fukushima Prefecture to lift its evacuation order after the 2011 nuclear accident, has faced unique challenges including prolonged inaccessibility, delayed reconstruction, and persistent social and psychological barriers in its recovery process that left a deep impression on its residents’ sense of belonging, trust in authorities and future outlook. While particular attention was paid by previous research to residents’ risk perceptions and health concerns( Canet et al., 2024; Ando et al., 2024; Ito et al., 2023; Ito & Goto, 2024), this study focuses on an underexplored dimension: residents’ and evacuees’ radiation knowledge-seeking behavior, particularly regarding radiation induced health effects. By integrating qualitative and quantitative analyses, the research aims to identify factors that motivate the desire for radiation knowledge and to provide actionable information to experts and authorities to support Futaba’ s recovery.
This article is part of the reflection conducted since 2020 on the role of the co-expertise approach recommended by the International Commission on Radiological Protection( ICRP) in terms of radiation risk communication after a nuclear accident. A first article( Thu Zar et al., 2022) had highlighted that, given the complexity of post-accident situations, technically oriented radiation risk communication was not sufficient on its own to restore trust between experts and the people concerned and to develop, among the latter, a practical culture of radiation protection relying on dialogue with experts and radiation measurements. A second article( Thu Zar, 2023) focused on analyzing the willingness among residents of the city of Tomioka, another municipality in Fukushima Prefecture whose residents have been evacuated during a long time, to engage in dialogue with experts and to perform radiation measurements. This article shed light on who are the residents motivated to engage in the co-expertise process after the nuclear accident. It showed that the desire to engage in dialogue with experts on radiation exposure and health effects was mainly found among people over 60 years old who were reluctant to eat food produced in the city and drink tap water, and who had already experience with radiation measurements.
Building on previous research conducted by Nagasaki University, which focused on the perception of risks related to radiation health effects and in particular on genetic concerns( Orita et al., 2015; Takamura et al., 2018; Xiao et al., 2024), this study explores how the type of information sources and the preferences on the forms of communication with experts influence knowledge-seeking behavior in relation to health issues. This exploration aims to refine the risk communication approaches of the authorities in the context of post-disaster recovery. Finally, the study aims to consolidate previous findings regarding residents’ motivations to engage with experts and perform radiation measurements, i. e., to implement the co-expertise process.
2 The Futaba context
Futaba Town is located in the central part of the Hamadori region, between Namie Town to the north and Okuma Town to the south( see Fig. 1). The total area is about 50 km 2. Although the city is primarily agricultural, its industrial structure experienced significant changes with the construction of the Fukushima Daiichi Nuclear Power Plant( FDNPP) in the late 1960s, which increased employment and favored significant growth in the city.
On March 11, 2011, in the early afternoon, the town of Futaba was severely damaged by the Great East Japan Earthquake and Tsunami. The disaster caused widespread destruction, including homes but also businesses. It also seriously damaged the Fukushima Daichi Nuclear Power Plant( FDNPP), operated by the Tokyo Electric Power Company( TEPCO), located just a few kilometers from the town center. In response to escalating risks at the plant, the Japanese government declared a state of nuclear emergency that evening, initially ordering evacuations within a 2-km radius, then extending it to 10 km the following morning. Eventually, as reactor cores melted, containment breaches occurred, leading to significant radioactive releases into the air and the sea.
Due to its proximity to the FDNPP, Futaba Town was significantly affected by the radioactive releases. While ambient dose rates recorded in various locations within the town in September 2011 ranged from 1.8 mSv / h to 29.05 mSv / h, earlier data from March 2011 shortly after the accident show that in some areas, dose rates temporarily reached around 1000 mSv / h( 1 mSv / h), indicating extremely high initial exposure levels( Fukushima Prefecture, 2011). The Japanese government expanded the evacuation order on April 11, 2011, designating a 20-kilometer radius that included Futaba as a restricted area. According to UNSCEAR, individuals within this evacuation zone were estimated to have received an effective dose of less than 10 mSv before and during the evacuation, with those evacuated early( on March 12, 2011) receiving approximately half that dose. These dose estimates were derived from modeled assessments of external radiation exposure due to radioactive deposition, notably of 137Cs( UNSCEAR, 2013). Specifically, in Futaba town, 82 % of evacuees were estimated to have received external radiation doses below 1 mSv, while 14.3 % would have been exposed to doses between 1 and 2 mSv, and only 2.4 % would have received doses between 2 and 3 mSv. A small proportion of individuals( 1.3 %) were estimated to have received doses above 3 mSv, with the highest estimated dose being 15 mSv( Fukushima Prefecture, 2012). Despite a gradual decline in