It’s the energy in the center (or nucleus) of an atom. Atoms make up everything in the universe and are held together with great force. In a process called fission, atoms are broken apart, and the energy released can be used to generate electricity at power plants, including the one in Japan that was damaged. Atoms of uranium, a common element that can be mined from the Earth, are used in nuclear reactions. In fission, a tiny particle called a neutron hits a uranium atom; the atom splits, releasing more neutrons and generating a chain reaction. That reaction releases huge amounts of energy. That energy can boil water to create steam, which in turn causes turbines to spin, generating electricity in a power plant.
What is a nuclear reactor?
A nuclear reactor is the device in a power plant where fission takes place. Pieces of uranium about the size of your fingertip get stacked up in 12-foot-long metal tubes, called rods. Bunches of rods form the core of the reactor.
So what happened in Japan?
Rods are normally kept under water, which keeps the reactor core cool. When the earthquake hit last Friday, the entire electrical grid went down, just as it can here when we have an ice storm. The nuclear plant switched to a backup system of generators. But an hour after the earthquake, the tsunami hit the plant, knocking out the generators. Backup batteries lasted only eight hours. Without power, the water couldn’t circulate and began to boil away, allowing the rods to get hot. The inability to keep cooling water on the fuel rods led to explosions and fires. Those events have sent radioactive elements into the air. High levels of radiation can be dangerous, even deadly. Close to the reactors, the radition levels have gone up and down. About 50 workers trying to fix the problem are risking their lives to save their fellow citizens.
Are people getting sick now?
No. People within 19 miles of the plant have been told to stay indoors. There is medicine that can treat the effects of radiation sickness, but it has not been given to people yet.
What will happen next?
Nobody knows for sure. If there isn’t water available to keep the fuel rods cool, the fingertip-size pellets can melt, like candles. This melting damages the core, which could lead to the release of more radioactive gases.
Is nuclear power safe?
That question has been asked for many years, and you will hear much more debate about it now because of the events in Japan. Nuclear power is very efficient. For example, one of those small uranium pellets can produce as much electricity as 150 gallons of oil. Many people see nuclear power as an alternative energy source. The situation at the Japanese reactors will have people talking about developing other power sources, including solar and wind.