Measurement and communication: what worked and what did not in Fukushima

The accident at Fukushima Daiichi nuclear power plant contaminated the soil of densely populated regions in Fukushima Prefecture with radiocaesium, which poses risks of internal and external exposure to the residents. However, extensive whole-body-count surveys have shown that internal exposure levels of residents are negligible. In addition, data from personal dosimeters have shown that external exposure levels have decreased, so the estimated annual external dose of the majority of people is <1 mSv in most areas of Fukushima. Despite these reassuring data, many problems remain in Fukushima, many of which are psychosocial rather than radiological. This article will discuss the roles of measurement and communication in the postaccident phase based on 5 years of experience.