The greatest significance of the Fukushima Daiichi nuclear power plant comes from its appearance in the news last year after the devastating tsunami hit Japan in March, 2011. Many newspapers reported that this was the most dangerous nuclear incident since Chernobyl in 1986.
What was considered most dangerous about this nuclear incident was that the earthquake and subsequent tsunami disrupted the power grid and generators which supported some of the vital control systems for the nuclear elements. One of the major areas of concern was that the reactors could no longer supply water to keep the fuel rods at a safe temperature. If the fuel rods overheated, it could cause a major explosion in the reactor, leaking dangerous radiation everywhere.
Despite the government's best efforts to control the situation, some radiation was leaked into the atmosphere, roughly 10% of what was leaked at Chernobyl.