On 11th March, 2011, a 9.0-magnitude earthquake and 46-foot tsunami crippled the Fukushima Daiichi nuclear complex in Japan. To mark the anniversary of the disaster, FRONTLINE asks if the risks of nuclear power outweigh the benefits.

Under the world's gaze, the Fukushima power plant suffered explosions and meltdown -- thousands of people were evacuated and a catastrophe was narrowly averted by workers who risked their lives as they struggled to gain control. Japan decided not to risk a repeat of the disaster -- today only a handful of Japan's 54 reactors are still operating, and all are expected to be closed by May 2012. Germany is following suit, and will close all of its 17 reactors by 2022. Whether the power gap is filled with renewable energy as planned, or by defaulting to fossil fuels remains to be seen. But where does this leave the rest of the world, which relies heavily on nuclear power?

FRONTLINE correspondent Miles O'Brien considers the implications for America's 104 reactors, 47 of which still do not meet federal fire protection standards that were set 35 years ago. As US regulators debate whether to relicense the 40-year-old Indian Point nuclear plant, which provides a quarter of New York City's electricity, Nuclear Regulatory Commission chairman Gregory Jaczko insists: 'The likelihood of a Fukushima accident happening here is very low.' Even so, last month the San Onofre power plant in California was shut temporarily after a series of accidents including a radiation leak and a worker falling into a reactor pool.