On March 11, 2011, the Great Tōhoku Earthquake triggered a 15-meter-high tsunami wave that hammered the eastern coast of Japan. The wave flooded the buildings, disabled the cooling and power supply of three reactors, and caused the nuclear fuel rods to overheat at the Fukushima Daiichi plant. With the power out, the emergency cooling generators weren’t functional, and explosions began in the reactor containment buildings; this in turn caused nuclear material to leak out of the plant. As every emergency response system failed, all three cores melted down almost completely within the first three days.
According to the World Nuclear Association, “The accident was rated 7 on the INES scale, due to high radioactive releases over days 4 to 6.” The meltdown released 940 PBq of radioactive material — about 15 to 18 percent of what Chernobyl released, which was about 5,200 PBq. The combined total of confirmed deaths and missing persons from the broader events was more than 22,000, but all of these people were alost due to the natural disasters and by health conditions immediately afterwards. There were no recorded deaths caused by the meltdown itself.
The Japanese government ordered more than 154,000 people to abandon their homes immediately following the accident because of concerns about radiation. As of last year, most of these people, about 97,000, remained displaced. Fukushima is thus far the most expensive disaster in history — the economic damages of this disaster are estimated at about $235 billion.
Both the Japanese government and civilian groups have been working to clean up after the accident since 2011. By early 2016, an estimated 30 to 40 years of cleanup remained, and the reactor three building was still thoroughly irradiated.
Tokyo Electric Power Company (TEPCO), the plant’s operator, has used robots to assess the damage, especially in areas where there is too much radiation for humans to work. Toshiba, a partner in the cleanup effort, has provided a scorpion-like robot for damage assessment, and the company also created an amphibious robot for fuel rod removal. Unfortunately, the radiation has made proper functioning impossible for most of the robots for any extended period of time.
Although the Fukushima Daiichi accident brought the previously simmering global debate about nuclear energy to a rolling boil, nuclear energy has actually become far safer after the accident. Experts agreed that the Fukushima disaster could have been avoided, and this alone suggests that, when best practices are followed, nuclear energy is safer than this experience would suggest.
Furthermore, “passive” safety systems that can cool reactors despite a power loss have become the industry standard since the accident. In the U.S., plant operators are enhancing procedures developed after 9/11 to ensure the safety of nuclear installations.
Nuclear plants generate clean energy without the greenhouse emissions, preventing around 80,000 deaths caused by air pollution annually. Nuclear is also safer than most other sources of energy: natural gas is 1.3 times as dangerous, coal is 27 times as dangerous, and hydroelectric is 46 times as dangerous. While the Fukushima Daiichi accident is a tragedy we will not soon forget, it does not negate the many benefits that nuclear energy represents.