Fukushima: 10 Years After

Ten years ago, on 11 March 2011, the most powerful earthquake ever recorded in Japan –and fourth in the world since modern recording started in 1900– occurred on the East coast of Japan in the Tohoku. It triggered a powerful tsunami with waves reaching 40.5 meters, travelling at 700 km/h up to 10 km inland in the area of Sendai region, and killing over 15,000 people.

The earthquake caused electrical power cuts and the emergency shutdown of the active reactors at the Fukushima Dai-ichi Nuclear Power Plant. The tsunami, with 14-meter-high waves at the level of the plant, swept over the plant wall and flooded the lower part of reactors 1-4, thus disabling the emergency diesel generators, which were needed for the circulation of coolant for the reactors’ cores. This led to what is referred to as the “Fukushima Dai-Ichi Nuclear Accident”, with reactor meltdowns, hydrogen explosions and the release of radioactive material in Units 1-3 between March 12 and 15, 2011. The Fukushima accident was classified as Level 7 (the highest) on the International Nuclear Event Scale, being the most severe nuclear accident since the Chernobyl accident in Ukraine in April of 1986.

Ten years ago, the most powerful earthquake ever recorded in Japan occurred on the East coast. It triggered a powerful tsunami killing over 15,000 people, swepting over the Fukushima Dai-ichi Nuclear Power Plant

Over 150,000 people living in the areas close to the nuclear power plant were evacuated, starting on 11 March. Evacuation led to many early deaths, in particular among severely ill patients hospitalised in intensive care units at the time of the accident, and among elderly residents of nursing homes due to stress and lack of health care and medicine (25% of those evacuated from one Minamisoma nursing home died within 90 days of evacuation).

Greg Webb / IAEA

The accident led to the release of considerable amounts of radioactivity, principally from Cs-137 (estimated release 6-20 PBq) and I-131 (100-500 PBq). The release is about 1/10th of that from the Chernobyl accident and, fortunately for the population of Japan, most (about 80%) was deposited over the ocean and was rapidly diluted in the water. Because of this, the affected populations received much lower levels of radiation doses than the populations affected by the Chernobyl accident. In the first year after the accident, the mean dose in the population of Fukushima prefecture was in the order of 2-3 mSv – similar to the average annual radiation dose from all sources (mainly natural and medical) in Europe.

Evacuation led to many early deaths, due to stress and lack of health care and medicine

Between 2011 and 2012, about 25,000 persons worked on the power plant site to decontaminate and isolate the radioactive material, and another over 75,000 worked offsite between 2012 and 2016 in environmental remediation activities. Most of the workers received very low doses – 13 mSv on average among the on-site workers in the first years and 2.5 mSv on average in recent years; among off-site workers the average annual dose is estimated to be in the order of 1 mSv.

An extensive decontamination programme was conducted over the following five years and has led to the lifting of the evacuation order in about 70% of the evacuated area in recent years. As of July 2020, it is estimated that there were still about 40,000 evacuees.

Health Effects

Concerning the health effects of the accident, to date, no increased risk of disease has been found in relation to radiation exposure, and, given the fortunately very low doses received by the affected populations, it is expected that any increase in cancer risk induced by the radiation would be too small to be detectable. A large number (233) of thyroid cancer cases were detected through an ultrasound screening programme of those who were children and adolescents in Fukushima prefecture at the time of the accident. Given the temporal trend and age distribution of the cases, it is judged that this increase is related to ultrasensitive screening methods rather than exposure to radiation. 

Although there may be no discernible direct effect from the radiation, it is striking that the accident and the measures taken to mitigate it and reduce exposures have caused important health, social and economic effects in the population. In the early post-accidental period, the evacuation itself caused immediate and avoidable deaths among evacuated patients and the elderly. There have also been reports of increased obesity, hyperlipidaemia, diabetes, hypertension and cardiovascular disease after the accident; these were mainly seen among evacuees, suggesting that they were more likely to be related to changes in lifestyle rather than to radiation. 

Although there may be no discernible direct effect from the radiation, it is striking that the accident and the measures taken to mitigate it and reduce exposures have caused important health, social and economic effects in the population

Most importantly, the accident –in particular the stress related to the accident, the evacuation, the lack and inconsistency of information, the distrust of authorities and uncertainties in radiation levels and radiation risks– has affected the mental health of the population, with increases in anxiety, depression, post-traumatic stress and substance abuse among evacuees, as well as adverse psychological effects in children and their mothers. With time and intervention, the prevalence of these effects appears to be decreasing.

Greg Webb / IAEA

In addition to the direct and indirect effects of the accident on health, the evacuation and environmental remediation have caused substantial social and economic hardship to the affected populations and have, more broadly, affected the Japanese society and economy.

Much like the SARS-CoV-2, radiation cannot be seen, smelled, or felt. It is noteworthy that uncertainty about exposure is a shared feature between viral disease epidemics and radiation accidents and can therefore lead to similar psychosocial effects. Further, the management of both radiation accidents and pandemics require the implementation of significant and high-impact measures (including the need for confinement and shielding) to protect affected populations, a need for health surveillance, as well as for effective communication and dialogue.

Much like the SARS-CoV-2, radiation cannot be seen, smelled, or felt. Uncertainty about exposure is a shared feature between viral disease epidemics and radiation accidents and can therefore lead to similar psychosocial effects

The lessons learnt from Fukushima and from the COVID-19 pandemic are important for the management of global catastrophes and disasters. The first key lesson is that preparedness is key, and it was lacking in both cases. The second is the need to ensure timely and reliable communication between health authorities, experts and affected populations during all phases of the crisis, and the need to engage citizens in the response, particularly in the later phases. These are essential to reduce the psychological, social and economic burden from such crises and increase the resilience of affected populations. Two general recommendations are particularly relevant for the management of this or any other crisis: do more good than harm, and encourage a strategy that targets the overall well-being of the affected population.

For more information

• COVID-19: COVID-19: What Can Past Nuclear Accidents Teach Us? Series | Series | COVID-19 & response strategy #24
• Fukushima, 6 Years Later: Consequences and Lessons
• Recommendations to Improve Health of Populations in Case of a Nuclear Accident (SHAMISEN Project)
• 2021 Fukushima Medical University International Symposium
• Fukushima Daiichi Nuclear Power Plant Accident, Ten Years On Flagship. Progress, Lessons and Challenges. OECD Nuclear Energy Agency