HowStuffWorks.com: How Japan's Nuclear Crisis Works

The recent crisis in Japan has set in motion a series of uncontrollable events in the nuclear energy community. Both the earthquake and the tsunami that followed hit the Fukushima II Dai Ni power plant causing several problems with the nuclear core. As the media told the world this story, panic spread across country. Evacuation of the area around the plant due to higher than normal radiation levels followed. An unsuccessful attempt by the Japanese authorities which included using helicopters carrying large containers of water to cool down the plant suggested that there was no prevention methods put in place before the disaster.

The workings of a nuclear power plant are in fact quite simple. Nuclear fuel, which in modern commercial nuclear power plants comes in the form of enriched uranium, naturally produces heat as uranium atoms split. The heat is used to boil water and produce steam. The steam drives a steam turbine, which spins a generator to create electricity. It seems that the problem in Fukushima plant was a pair of control rods which absorbed neutrons during the process of fission and also involved water pumps. The control rods were from the 1960s which was the most likely cause for their failure during the earthquake. The design's vulnerability comes into play if the electric pumps lose power. Without a fresh supply of water in the boiler, the water continues boiling off, and the water level starts falling. If enough water boils off, the fuel rods are exposed and they overheat. At some point, even with the control rods fully inserted, there is enough heat to melt the nuclear fuel.

It has not however come to this point as of yet, according to the Japanese authorities. The reactor is stable for now. But how close have we come to nuclear disaster once again? Is another Chernobyl about to occur? The event in Japan is being described as Level 6 INES events (International Nuclear and Radiological Event Scale). Chernobyl is level 7. The enormity of the disaster is just being analyzed. Hopefully this crisis will stimulate technologies that will make nuclear energy safer rather than abandoning it completely.

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