Out of all the devastation wrought by the Tohuku earthquake and tsunami in March 2011, the escalating disaster at the Fukushima nuclear plant has ended up having the biggest global impact. A catastrophic loss of cooling led to meltdowns, explosions and a release of radioactive material into the atmosphere – and seems to have slammed the brakes on a nuclear industry that had been pretty bullish about its role in weaning us off of our fossil fuel addiction, as safety concerns have once more come to the fore.
Japan, which prior to Fukushima generated almost a third of its electricity at nuclear power stations, is reconsidering its generation mix: the government recently announced that it plans to shut down all 50 of its presently operating reactors (many of which have already been shut down in the months following Fukushima for safety checks), although this commitment seems to be somewhat at odds with a commitment to go ahead with constructing new, already-approved nuclear plants. In the wake of an incident which elevates safety concerns above the perceived benefits of greater energy independence and lower carbon emissions that nuclear power promises, it’s easy to grasp the reasoning behind this; especially in the light of the parliamentary investigation that uncovered a disturbing degree of collusion between the TEPCO power company and the Japanese government to water down or circumvent earthquake safety measures.
It has been more puzzling to see the responses from Germany, who last summer decided to phase out all of it’s nuclear power plants by 2022, and France, who this summer elected a new government that has promised to slash the proportion of nuclear in their generation mix by a third, from 75% to 50%. Although some public concern is unsurprising, the fact remains that a Fukushima-type incident requires a nuclear plant built on the coast near a subduction zone capable of generating a major earthquake and subsequent tsunami. Unlike Japan, Germany and France are not high up on my list of possible places where these criteria are met. However, it is also unlikely that Japan is the only place on earth which faces these risks – a possibility that is the subject of a recent short paper in the Journal Natural Hazards, which adds up all the nuclear plants built or in the process of being built in coastal areas that could get in the way of a tsunami generated by a great subduction zone earthquake. Although the vast length of coastline at risk from large tsunamis includes much of the Pacific Rim, it is only in South-East Asia that these danger areas host nuclear power plants. The Natural Hazards study identifies 17 separate sites hosting a total of 49 reactors that are potentially at risk, distributed between Japan, China, South Korea, Taiwan, India and Pakistan. Four of these sites are in the process of being expanded, adding 9 reactors to the total; and a further 16 reactors are being built at 7 entirely new at-risk sites, 5 of which are in China.
It is unclear – and this paper does not address – what, if any, impact the Fukushima disaster has had on the safety measures in place at the at-risk nuclear plants outside of Japan, and the worst-case scenarios being designed into the plants under construction. It seems unlikely that the seismic risks have been completely ignored, but one of the lessons of the Tohuku earthquake is that our understanding of the long-term tsunami hazard is still extremely tenuous, and our assumed worst-case scenarios may be nowhere near the actual worst.
On the flip side, it is easy to be critical of decisions to locate a nuclear plant in areas with high tsunami hazard, but that ignores the fact that many other factors, such as population distribution,access to cooling water, and the viability of other generation sources, are also important constraints. Nonetheless, it seems clear that the nuclear backlash from Fukushima has perhaps not been focussed where the geological facts suggest it should be.
Discussions like this emphasise how important it is to teach think properly about geological hazards: our DonorsChoose Giving Page includes several projects that get students thinking about how earthquakes work. Please think about donating a few dollars to the cause!