On March 11, a magnitude-9.0 earthquake struck off the coast of Sendai in Japan, knocking out power at the nearby Fukushima Daiichi nuclear plant. In the hours and days that followed, three of the plant's six reactors melted down, triggering a series of explosions and fires at the site. Six months later, what progress has been made to stabilize the plant, and what is yet to be done? [More]