Fukushima accident: What happened?

An overview is presented on the progression and the impact of the accident in the Fukushima-Daiichi Nuclear Power Plant based on the public information until December, 2011. The accident was caused by a loss of powers and heat sink for cooling which was triggered by a massive earthquake and a successive tsunami, and resulted in release of radioactive materials, ∼15% of that in the Chernobyl, to environment and evacuation of residents around the plant. It should be noted that other ten reactors were also hit by the earthquake and tsunami but could reach cold shutdown owing to availability of cooling.Contamination of land and sea around the plant is so serious as that living and fishery are prohibited. Nevertheless, neither death due to radiation nor serious radiation exposure has been reported despite of various problems in the evacuation procedure and radiation management.Various actions which were undertaken to recover the plant and to reduce the radiation hazard to residents are also described.

► Fukushima accident.
► Contamination and dose.
► Hazard.
► Recovery actions.