It is indispensable for the survival of the State and local communities around nuclear facilities to take effective measures for controlling catastrophic damages from a nuclear severe accident. Japanese people keenly realized this lesson from the nuclear disaster in Fukushima began on 11 March 2011. This paper discusses three topics concerning the Fukushima accident, and severe accidents of nuclear facilities in general．
First, we evidently conclude that the developing process of the Fukushima nuclear accident could be understood by ordinary people with certain professional knowledge about nuclear severe accidents． A circumstantial evidence is my own experience at the beginning of the Fukushima accident. On the contrary, the Japanese government consistently hesitated to inform the actual state of affairs concerning Fukushima disaster (chapter1 to 3)．
Second, we make a comparative analysis between the damage caused by nuclear explosive devices and that of nuclear facilities like nuclear power plants, to clarify the characteristics of damage from nuclear severe accidents (chapter4 to 6)．
Third, we analyze the characteristics of the failure of the Japanese government, local governments, and the Tokyo Electric Power Company (TEPCO) at the Fukushima nuclear disaster, and indicate the challenge of improving Japan nuclear disaster countermeasure system (chapter7, 8)．
