The catastrophic accident at Japan's Fukushima No. 1 nuclear plant earlier this year undermined confidence in, and support for, nuclear power around the world. The plant north of Tokyo on the Pacific coast was hit by a series of explosions, fires and serious radiation leaks after a massive earthquake and the monster tsunami waves it generated cut outside power to the plant, causing reactor fuel rods to heat up dangerously.
It took several months to bring the nuclear crisis under control. Countries with the world's 440 commercial reactors in operation, and those with plans to use atomic power to generate electricity, paused to check safety and other risks.
They had to ask whether nuclear energy was more cost-effective than other alternatives, including renewable energy.