How Does Nuclear Energy Work?
The term nuclear energy has become synonymous with production of power and also with potential dangers from radiation. Uranium is most commonly used fuel for nuclear power plants. Unfortunately, nuclear energy is not renewable but the metal uranium is widely available through the world. There are different types of uranium but the one used for nuclear power is U-235.
It's true you can find uranium in rocks in many parts of the world, but U-235 is not as widely available. This form of uranium is preferred for nuclear energy production because the atoms of U-235 can be split easily. In the U.S., uranium mines are found in the western states. Before nuclear energy can be created, uranium must be extracted from rock and processed to be used as a fuel.
Nuclear energy is a result of nuclear fission. A tiny neutron hitting one atom of U-235 splits the uranium atom and energy is released in the form of heat and radiation. At the same time, more neutrons are released when the atom is split and these neutrons move on to split other atoms of U-235. This process is the chain reaction that can be used to create electrical energy.
Plants Generate Electricity from Nuclear Energy
About twenty percent of the electrical power in the U.S. is generated by nuclear power plants. The resulting electricity is equal to the power used in New York, Texas and California. There are 65 nuclear plants and 103 nuclear reactors throughout the U.S. Most of the power plants are located in the eastern half of the country.
The most recent nuclear reactor to begin operation was in 1996 and the next scheduled plant opening will not occur until 2013 at the earliest. Plants that producce nuclear energy are not unattractive features on the landscape of a city. Some, but not all, nuclear plants have cooling towers and most look like huge domes made of concrete.
Nuclear fission is the process that is used to product nuclear energy. Atoms are split in two and form smaller atoms. Each time an atom is split, energy is released. In a nuclear power plant, the center of the action is the core. This is where the uranium fuel is located. U-235 is processed to form it into ceramic pellets.
Each pellet is small (about the size of a fingertip) but one pellet has the capacity to produce as much electrical power as 150 gallons of oil. The pellets are packed into 12-foot fuel rods made of metal. A fuel assembly is a bundle of fuel rods and each reactor core of a nuclear power plant has multiple fuel assemblies.
Splitting the uranium atoms creates fission and releases heat. The heat is used to boil water to steam and the steam turns turbines to generate electricity.
Once steam has passed over the turbine blades it is cooled to return it to liquid form and it is pumped into a cooling tower. This water can be used again and again as it is heated to steam, cooled back to water and then heated again. The presence of this water is crucial to the safety of the fission process.
In the U.S., there are two types of nuclear reactors used. In a boiling water reactor, the water is converted to steam and the steam turned the turbine directly to generate electricity.
In a pressurized-water reactor, the water is not converted to steam. Instead, the heated water is pressurized and remains liquid. The water flows through a steam generator and heats tubes that are part of the generator.
The water flowing through the generator tubes is radioactive while on the outside of these super hot tubes is clean water which boils and turns to steam. The radioactive water flows through the tube of the steam generator and then is funneled back to the reactor core to be reheated and recycled. The clean water used comes from the ocean, rivers or lakes.
Without processed uranium, nuclear energy does not exist. Most of the U-235 used in the U.S. is imported from Russia, Kazakhstan, Uzbekistan, Australia, Canada, and Niger. While uranium is widely found worldwide, U-235 is relatively rare.
One of the potential problems with nuclear energy is competition for this previous uranium ore. Construction of nuclear power plants in the U.S. has been slowed by environmental concerns about safety but other countries have gone full steam ahead in adding nuclear energy power plants to fill their ever increasing need for more electrical power.
In the U.S., nuclear energy plants operate under licenses which were originally for thirty years. The licenses of about half of the U.S. nuclear plants have been extended to sixty years and plans for another 10-12 new plants are under consideration.
One problem has been lack of public faith in the inspection and maintenance of older plants. The safety record of nuclear reactors is actually good when the process is compared to other energy producing methods. However, when there is a problem it can be a significant problem that endangers the land, wildlife and the lives of people as well.
Effects of the Chernobyl disaster in Russia are still being studied and damage caused to people in the area is still a major health risk.
In 2011, the Fukushima Daiichi nuclear plant in Japan was damaged by an earthquake. Perhaps more than any other nuclear disaster, the Fukushima Daiichi incident is a great source of concern to the public.
In Chernobyl there were defects that led to a disaster. In Japan, the disaster was an Act of God that could not be foreseen or prepared for. Perhaps the most frightening aspect of the Fukushima radiation leak was the slowness in which the problem was acknowledged and the length of time it took to assess the danger to the populace.
The dangers of radiation are well known and documented and though nuclear reactors operate without incident day after day around the world, the public is still rightfully concerned about potential leads of radioactive materials.
The latest problem in Japan caused many countries to re-evaluate plans of proposed nuclear power plant construction and stop the construction until further studies on safety issues could be done.
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Uranium is a natural metal that is mined from rock and must be processed before it can be used to produce electrical power. Though there are various types of uranium the U-235 is used to produce electricity because the atoms of U-235 can be easily split.
When neutrons bombard the uranium pellets in a nuclear energy plant, the uranium atoms split. This releases heat energy and also additional neutrons and small atoms which then split to form what is called the nuclear reaction. Though many environmentalists are not comfortable with the use of nuclear energy, it is a potential energy source for the future.