Nuclear Energy

Electricty Generation Technologies

Electricity from Nuclear Energy

Nuclear energy originates from the splitting of uranium atoms in a process called fission. Fission releases energy that can be used to make steam, which is used in a turbine to generate electricity. Nuclear power accounts for approximately 19 percent of the United States' electricity production. More than 100 nuclear generating units are currently in operation in the United States.¹ No nuclear power plants have been built since 1996.²

Uranium is a nonrenewable resource that cannot be replenished on a human time scale. Uranium is extracted from open-pit and underground mines. Once mined, the uranium ore is sent to a processing plant to be concentrated into a useful fuel (i.e., uranium oxide pellets). This uranium enrichment process generates radioactive waste. Enriched fuel is then transported to the nuclear power plant.

At the power plant, the uranium oxide pellets are bombarded with neutrons, causing the uranium atoms to split and release both heat and neutrons. These neutrons collide with other uranium atoms and to release additional heat and neutrons in a chain reaction. This heat is used to generate steam, which is used by a turbine to generate electricity.

Environmental Impacts

Although power plants are regulated by federal and state laws to protect human health and the environment, there is a wide variation of environmental impacts associated with power generation technologies.

The purpose of the following section is to give consumers a better idea of the specific air, water, land, and radioactive waste releases associated with nuclear power electricity generation.

Air Emissions

Nuclear power plants do not emit carbon dioxide, sulfur dioxide, or nitrogen oxides. However, fossil fuel emissions are associated with the uranium mining and uranium enrichment process as well as the transport of the uranium fuel to the nuclear plant.

Water Resource Use

Nuclear power plants use large quantities of water for steam production and for cooling. When nuclear power plants remove water from a lake or river for steam production and cooling, fish and other aquatic life can be affected.

Water Discharges

Water pollutants, such as heavy metals and salts, build up in the water used in the nuclear power plant systems. These water pollutants, as well as the higher temperature of the water discharged from the power plant, can negatively affect water quality and aquatic life.

Although the nuclear reactor is radioactive, the water discharged from the power plant is not considered radioactive because it never comes in contact with radioactive materials.³ However, waste generated from uranium mining operations and rainwater runoff can contaminate groundwater and surface water resources with heavy metals and traces of radioactive uranium.

Radioactive Waste Generation

Every 18 to 24 months, nuclear power plants must shut down to remove and replace the "spent" uranium fuel.⁴ This spent fuel has released most of its energy as a result of the fission process and has become radioactive waste.

All of the nuclear power plants in the United States together produce about 2,000 metric tons per year of radioactive waste.⁵ Currently, the radioactive waste is stored at the nuclear plants at which it is generated, either in steel-lined, concrete vaults filled with water or in above-ground steel or steel-reinforced concrete containers with steel inner canisters. The Department of Energy is currently preparing a license application to construct a permanent central repository at Yucca Mountain. If the license is granted, the repository could begin to accept waste by 2012. In addition to the fuel waste, much of the equipment in the nuclear power plants becomes contaminated with radiation and will become radioactive waste after the plant is closed. These wastes will remain radioactive for many thousands of years.

Uranium processing produces radioactive wastes that must be adequately stored and isolated to minimize the risk of radioactive release. The management, packaging, transport, and disposal of this waste is strictly regulated and carefully controlled by the U.S. Nuclear Regulatory Commission and the U.S. Department of Transportation.

Land Resource Use

The construction of nuclear power plants can destroy natural habitat for animals and plants or contaminate local land with toxic by-products. For example, the storage of radioactive waste may preclude any future re-use of these contaminated lands.

Reserves

In 2003, U.S. uranium ore reserves were estimated at about 890 million pounds. These reserves are located primarily in Wyoming and New Mexico.⁶

U.S. Department of Energy, Energy Information Administration, Uranium Industry Annual 2000 (PDF) (81 pp., 491K, About PDF).
Ibid.
Nuclear Energy Institute, Fact Sheet: Nuclear Energy and the Environment (PDF) (3 pp., 57K, About PDF) . July 2000.
Ibid.
U.S. Department of Energy, Energy Information Agency, Nuclear Power Generation and Fuel Cycle Report 1997.
U.S. Department of Energy, Energy Information Administration, U.S. Uranium Reserves Estimates, June 2004.