Energy is all around us. Energy can be classified as potential or kinetic. Potential energy is stored energy. Kinetic energy is moving energy. There are many types of potential and kinetic energies. Nuclear energy is a type of potential energy because it is the energy stored inside the nucleus of an atom.
Atoms are the building blocks that make up everything around us. They are too small to see, so scientists use models to explain how atoms look and act. All atoms are made up of a central nucleus surrounded by orbiting electrons. Protons and neutrons are located inside the nucleus. Protons have a positive charge, and neutrons have no charge. The tiny electrons orbiting the nucleus have a negative charge.
Usually, positive charges repel each other, but in the nucleus, protons are packed tightly together. The strong nuclear force holds the protons and neutrons together inside the nucleus. The strong nuclear force is over 1,000 times stronger than gravity.
Scientists have learned to capture the energy stored within the nuclei of atoms by breaking an atom into smaller pieces through nuclear fission. They call the energy released nuclear energy.
Atoms are defined by the number of protons they have. Scientists often use uranium to release nuclear energy. Uranium has 92 protons. When a neutron is shot at a uranium atom, it splits the atom into two smaller atoms. For example, a uranium atom can break apart into a cesium atom and a strontium atom. Cesium atoms have 55 protons, and strontium atoms have 38 protons. The rest of uranium’s protons are released as radioactive particles. Neutrons are also released during the reaction. These neutrons collide with other uranium atoms creating a nuclear chain reaction in which many more atoms are split.
When an atom is split, it releases thermal energy and radiation. In a nuclear power plant, the thermal energy is used to turn water into steam. The steam turns a turbine, and the mechanical energy of the spinning turbine is converted into electrical energy.
A similar process is used to generate electrical energy in traditional power plants, but coal or natural gas is used to turn the water into steam. Many people believe nuclear power is better than conventional power sources because it doesn’t release any pollution from burning coal or natural gas. Nuclear energy is also efficient. One small uranium pellet can generate the same amount of electrical energy as one ton of coal or 17,000 cubic feet of natural gas.
However, nuclear energy isn’t completely safe. Nuclear waste from a nuclear power plant is incredibly hot and radioactive. It can take 100,000 years for the waste to become safe for humans. Finding a safe place to store this material is difficult, and the United States currently has over 90,000 metric tons of nuclear waste in temporary storage.
There can also be accidents at nuclear power plants. In 1986, a fire started in a nuclear power plant in Chernobyl, Ukraine. This fire released radioactive particles into the air. Radioactive protons, neutrons, and electrons spread through the wind and entered the water cycle. Radioactive rain fell as far as Scotland and Ireland. The pine forest surrounding the power plant dried up and turned red. Cattle and horses in the area died. Over 100,000 people had to be relocated after the accident.
Radioactive particles are dangerous because they can pass through human tissues and attack our DNA. The changes to our genetic material cause cancer and birth defects. Exposure to extreme radiation can cause immediate death.
We are exposed to radiation every day. The Sun releases low levels of radiation as a result of nuclear fusion. Unlike the nuclear fission used in nuclear power plants, nuclear fusion releases energy by combining atoms. The Sun is continually fusing hydrogen atoms to form helium atoms. In about 5 billion years, the Sun will run out of hydrogen atoms, and it will burn out.
Nuclear reactions are also happening deep inside the Earth. Most of Earth’s geothermal energy comes from nuclear fission reactions in the inner core. Atoms such as potassium and thorium are naturally breaking down into smaller atoms and radioactive particles. The heat released by these reactions creates the convection currents in the mantle and causes continental drift.
Nuclear energy is a powerful energy. Nuclear reactions in the Sun provide energy for photosynthesis, the water cycle, and wind power. Nuclear reactions in the inner core are continually changing the landscape of Earth, and nuclear reactions in power plants generate clean electricity to use in our homes, schools, and businesses.