Core concerns
The fire that followed the failure of emergency generators at the Daiichi nuclear complex raised the terrifying prospect of radiation leaking and spreading. The core of the Unit 1 reactor melted, and spent nuclear fuel, stored under pools of water, sprang to life as cooling pumps stopped.
Fukushima's nuclear reactors had been built to withstand the worst, including earthquakes and tsunamis. Sensors successfully shut down the reactors, but when a wall of water 30 feet high crashed over the 20-foot protective concrete walls, electrical power, essential for cooling, was lost.
The plume of radiation reached as far as Canada. Closer, it was far worse. Japan knows that swathes of its territory will be contaminated, perhaps uninhabitable, for the rest of the century. In July, for example, beef, vegetables, and ocean fish sold in supermarkets were found to have radioactive caesium in doses several times the safe level. [1]