Nuclear power is still one of the safest and cleanest ways to produce electricity — regardless of the doomsaying from the public and media after an 8.9-magnitude earthquake nearly caused a meltdown at the Fukushima Daiichi nuclear power plant in Japan.
Nuclear power is not well understood by the general public and the media. So the results of the disaster in Japan have been completely blown out of proportion, to the point that the U.S. government is calling on the president to back off on nuclear power programs for at least a little while.
This is pretty unfortunate, because nuclear power is one of the next best alternatives to fossil fuel-fired plants. Other cleaner power sources, such as solar and wind power, are still in their infancy and are nowhere near as efficient as nuclear reactors.
Japan’s nuclear reactors generate heat through a process called nuclear fission. This happens when uranium atoms collide with other particles — typically a neutral particle called a neutron present in most atoms — and split off into smaller elements. This reaction produces a tremendous amount of heat, which boils the water in the reactor, and several free particles. Neutrons are also among those particles, which then go on to collide with other uranium atoms in the reactor to create more nuclear fission reactions.
This type of reaction is called a chain reaction, because once it begins it creates a cascading effect that can continue for a long period of time. Reactors like the ones in Japan are able to control it by inserting an alternative type of rod that absorbs free neutrons. This lowers the probability of free-floating neutrons colliding with other uranium atoms, which would again create more heat and free-floating particles.
As the water within the reactor boils, it turns into steam. That steam is used to power a turbine that then creates electricity. It’s a much cleaner procedure than a fossil fuel-fired power plant. The nuclear reactor is housed in several containment units, where each serves as a protective layer and a fail-safe for the one before it. Japan’s nuclear reactors featured three containment units, the last of which is designed to “catch” falling nuclear material after a meltdown and keep it from burning its way into the ground.
Several disruptions in external power to the nuclear plant eventually made it difficult to pump clean water into the plant and keep the nuclear fuel cool. The earthquake knocked the nuclear plant off the grid, but it had diesel generators. These were disrupted by the tsunami that followed the earthquake, forcing the plant to go to backup battery power while diesel generators were transported to the plant.