Following the high tsunami caused by the earthquake off the Pacific coast of Tohoku (2011 Tohoku earthquake) on March 11, 2011, Fukushima Power Plant #1, operated by Tokyo Electric Power Company (TEPCO), suffered a complete loss of electric power, and the cores of reactors #1 through #3 went into meltdown. This moment spelled the end of the myth of the safety of Japanese nuclear power. Nevertheless, nuclear power safety researchers had previously pointed out that nuclear reactors would quickly go into meltdown during a complete loss of electric power, unless the optimal safety measures were taken.

There are aggressive safety research programs in not only the field of nuclear power, but also in the fields of aircraft, high-speed trains, and others. When something compromises passengers’ safety in an aircraft or a bullet train, it is withdrawn from its function, i.e. the aircraft or train is landed or stopped, and is not used again until we can be sure it is safe. Things are not so simple with nuclear power plants; even after the nuclear reactions are stopped for safety by control rods or boric acid, it remains necessary to continue cooling of the reactor due to the decay heat. A nuclear reactor must be restored to a safe condition while it continues to “run”. Thus, a nuclear reactor presents a more stringent environment than an aircraft or a bullet train, and requires a more sophisticated set of technologies to maintain safety.

The probability of a serious accident in a nuclear reactor is said to be far lower than in an aircraft. Nonetheless, air travel is accepted by people as a means of transportation because of its convenience. There is a high perceived benefit in exchange for a sufficiently low perceived latent risk, in both air travel and bullet trains, so these are considered to be safe. There is no such thing as complete safety in this world. There have been tragic accidents in the long histories of aircraft and trains. However, long years of patient thought and efforts have gone into ways to establish safety and reduce the risks of high-speed travel, resulting in the industries we know today. And what of nuclear power? When we think of the people of Fukushima, who have had to bear not only the disaster of the tsunami, but also a nuclear disaster, it is clear that an exacting, sophisticated level of safety technology is required in the design of nuclear reactors. Will nuclear power be accepted as beneficial to humanity in the future?

There is a so-called “Earth calendar” which presents the 4.6 billion-year lifetime of the Earth as a single calendar year.

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