In one week, Japan's Fukushima Daiichi power plant has had hydrogen explosions at three reactors, and a radioactive fire at a fourth. It sparked a massive evacuation of the Japanese countryside and the government is already banning crops and dairy products from three surrounding prefectures. Nuclear power plants pose a risk that insurance companies can't quantify, and won't insure -- so how did we wind up with so many of them? Journalist Stephanie Cooke, who's covered the nuclear industry for close to 30 years, provides the long view.