The disaster at Fukushima Daiichi Nuclear Plant in Japan on March 11, 2011, destroyed tens of thousands of lives and had ripple effects around the world as nations reliant upon or considering nuclear power rethought their plans.
The meltdown of three of the six nuclear reactors at the Fukushima Daiichi plant, about 130 miles north of Tokyo, was the worst nuclear disaster since the Chernobyl accident in Ukraine in 1986. The result of a 9.0-magnitude earthquake and associated tsunami waves that reached heights exceeding 100 feet, the disaster demonstrated that nuclear power plant operators may not have anticipated the full range of worst-case scenarios that could beset their facilities.
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The tsunami's swift and massive waves crippled the power plant by taking out its power supply and cooling system, with workers resorting to desperate measures to cool the reactors to prevent an even more significant disaster.

Yuko Suzuki, left, and Akemi Watanabe offer prayers for victims of the March 11, 2011 earthquake and tsunami in Minamisoma, Fukushima prefecture, northeastern Japan, Tuesday, March 11 2014.
Image: Koji Sasahara/Associated Press
The damage at the plant was so severe that more than 100,000 residents of the nearby Fukushima Prefecture had to be relocated, and complex cleanup operations at the plant continue.
While the damage was confined to Japan, the waves were detected across the Pacific Ocean, moving at speeds of up to 500 mph.
This map depicts where the tsunami traveled, and what times it reached certain areas, after the Japan earthquake on March 11, 2011, which struck at 2:46 p.m. local time.
In the U.S., the disaster spurred the Nuclear Regulatory Commission, which is responsible for overseeing the 100 nuclear power plants operating in the country, to re-assess safety planning and issue some new requirements for plants that are of similar design as Fukushima. Exelon, which is the country's largest nuclear-reactor operator, runs 17 of the commercial reactors. According to a New York Times report, the company expects to spend up to $500 million upgrading its plants based on lessons learned from Fukushima.
“Fukushima woke up the world nuclear industry, not just the U.S.,” the chairwoman of the NRC, Allison M. Macfarlane, told the Times. “It woke everybody up and said: ‘Hey, you didn’t even think about these different issues happening. You never thought about an earthquake that could create a tsunami that would swamp your emergency diesel generators and leave you without power for an extended period. You never planned for more than one reactor going down at a site, you have to think about that now.’ ”

People offer prayers at 2:46 p.m., the time the March 11 earthquake hit three years ago, at Kitaizumi beach in Minamisoma Fukushima Prefecture, northeastern Japan, Tuesday, March 11, 2014.
Image: Koji Sasahara/Associated Press
Scientists at the U.S. Geological Survey have updated earthquake data for the central and eastern U.S., providing nuclear operators with new information about the earthquake risks their plants face, and the safety standards they should meet. Coastal plants face other risks, such as storm surge flooding from coastal storms such as hurricanes, and the long-term challenge of sea level rise due to global warming.
This map from esri allows you to enter a location and identify three of the nearest U.S. nuclear facilities, as well as seismic risk information. The yellow circles around each location represent a 50-mile radius around each plant.
The timeframe for implementing all of the lessons learned, however, is lengthy, with the NRC and the nuclear industry still debating many potential safety measures, and many decisions remaining.
In the meantime, much of the momentum that the nuclear industry had going into 2011 — with several proposals on the table for new power plants — was lost with Fukushima, given the associated increase in public concern regarding nuclear safety. In addition, low natural gas prices also undercut nuclear's viability, according to the World Nuclear Association, an industry trade group.
Japan's nuclear plants have been shut down after Fukushima, leading to a spike in the nation's greenhouse gas emissions, as utilities relied more on dirtier forms of energy, like coal and natural gas.
The Japanese government is working to restart their reactors, however, despite public opposition. Before the earthquake and tsunami, nuclear power generated about a quarter of Japan's electricity.
In the wake of the accident, Germany decided to close its oldest nuclear power plants and shutter the remaining reactors by 2022, also leading to repercussions in the country's greenhouse gas emissions trends.
However, research continues in the U.S. on advanced reactor concepts that might be less vulnerable to threats like earthquakes, sea-level rise and severe storms. And nations like China and India, which are trying to expand electricity to keep pace with burgeoning populations and high rates of economic growth, are still looking to nuclear power as an attractive, cleaner energy option.