I have dealt with the potential and actual impact of natural disasters such as earthquakes, tornados, hurricanes, and tidal waves on nuclear reactors. However, there is another natural danger that is not often raised with respect to endangering nuclear power plants.
Japan is currently debating the restart of some of its fleet of fifty nuclear reactors after all nuclear power plants were shut down following the Fukushima disaster in March of 2011. Fifteen billion dollars has been allocated for hardening Japan's reactors against natural disasters.
The Ring of Fire is a horseshoe shaped zone of earthquakes and volcanoes around the Pacific Ocean. The Ring of Fire is caused by plate tectonics. Ninety percent of the world's earthquakes and eighty percent of the world's largest earthquakes occur around the Ring of Fire. Many active volcanoes are found along the Ring of Fire. Ten percent of the worlds active volcanoes are found in Japan which is part of the Ring of Fire. There are one hundred and ten active volcanoes in Japan.
The Kyushu Electric Power Company's (KEPC) nuclear power plant at Sendai in Kagoshima Prefecture is in an area where there are active volcanic sites. The Sakurajima volcano is only thirty miles from Sendai. There are five huge calderas in the Sakurajima complex. Caldera forming eruptions are devastating but rare. Some scientists estimate that the odds of such an eruption in Japan in any year is less than one in ten thousand. On the other hand, the head of the agency that monitors Japan's volcanoes has stated that there is no demonstrated way to predict eruptions.
The Japanese Nuclear Regulatory Authority has stated that, in their estimation, the risk of volcanic activity that might endanger the Sendai plant is negligible. Critics of the NRA report complain that the NRA is overestimating the ability of scientists to predict volcanic eruptions. They point out that while the risk might be small, the damage of such an event could be enormous. KEPC has announced that they will place monitoring gear around the Sakurajima volcano complex and they have plans to move nuclear fuel away from Sendai in case an eruption appears imminent.
The final hurtle in restarting the Japanese reactors lies in convincing the Japanese people that the reactors will be able to operate safely and survive threats from natural disaster such as volcanoes. The cost of keeping the reactors shut down is mounting as Japan spends billions of dollars to purchase other types of fuel to cover the roughly one third of their electricity that was generated by the nuclear power plants.
If the Japanese government approves plans to restart the Sendai reactors, the next step will be for the local citizens and government to engage in a series of public debates over restarting the reactors. The National government has been adamant that it will not restart reactors unless communities near the reactors approve.
Sendai nuclear power station:
