Nuclear power industry and the environment

DEFINITION: Electricity generated through the harnessing of the heat energy produced by controlled nuclear fission

Nuclear power has long been the most controversial source of electricity. High plant construction costs, safety concerns, waste disposal problems, and public mistrust all served to slow the growth of the nuclear power industry during the late twentieth century. In the early twenty-first century, factors such as nuclear power’s potential to meet electricity demand while reducing greenhouse gas emissions have increased its appeal.

Many of the environmental impacts of nuclear power plants are common to all large-scale electricity-generating facilities, regardless of their fuel. The most important are land use and related impacts on plants, animals, and ecosystems; nonradioactive water effluent and water quality; thermal of adjacent waters; and social impacts on nearby communities. Unique to nuclear power plants is the hazardous emitted by radioactive materials present in all stages of the cycle. Such radiation is contained in uranium ore when it is mined and processed, in fabricated uranium reactor fuel, in that has been fissioned, in contaminated reactor components, and in low-level radioactive waste—such as contaminated tools, protective clothing, and replaced reactor parts—generated by routine plant operation and maintenance.

Spent reactor fuel is highly radioactive and must be isolated from the for tens of thousands of years or more. Spent fuel can be reprocessed to separate out usable uranium and plutonium, but doing so generates large volumes of low-level that present disposal challenges of their own. Other challenges in waste handling and disposal arise at the end of a plant’s useful life, when the contaminated reactor must be dismantled and the radioactive and nonradioactive components disposed of in a process known as decommissioning.

Under normal operating circumstances, commercial nuclear power plants negligible radioactive emissions. The principal safety concern is that a severe accident could release large quantities of dangerous radioactive materials into the environment, as happened in 1986 at the Chernobyl nuclear plant in Ukraine. Roughly a quarter century after one of Chernobyl’s reactors exploded, radiation levels remain dangerously high within the deteriorating concrete containment structure surrounding the reactor, and levels within the exclusion zone that extends in a 30-kilometer (18.6-mile) radius around the plant site continue to be higher than normal background levels.

Early History

The nuclear power industry arose out of the technology developed during World War II to produce the atomic bomb. Postwar enthusiasm for new technology in general, combined with pressure to demonstrate peaceful uses for expensive and fearsome wartime nuclear technology, led to a strong US government effort beginning during the early 1950s to induce industry to develop nuclear energy. Large government subsidies and preferential treatment assisted the industry from its early days. Between fiscal year (FY) 1948 and FY2007, nuclear power received 53.5 percent of all federal energy research and development funds, totaling $85.01 billion in constant FY2008 dollars. One of the industry’s unique subsidies was the passage of the 1957 Price-Anderson Act, which limits the liability of nuclear power plant owners and equipment vendors in the event of a reactor accident.

The basic design of the first US nuclear power plants was adapted from early pressurized water reactor technology developed for submarines and other naval propulsion applications. Roughly two-thirds of the 104 commercial reactors in use in the United States are pressurized water reactors. In this reactor design, light (ordinary) water surrounds the nuclear fuel, which is made up of enriched uranium. The system is pressurized so that the fuel heats the water without boiling it. The resulting heat is used to boil a separate water supply, creating steam. The steam spins a turbine to generate electricity. The choice of this reactor design was largely driven by expediency and political considerations rather than an explicit effort to seek safe or reliable design features. The first large-scale commercial nuclear plant in the United States, which began operating at Shippingport, Pennsylvania, on a demonstration basis in 1957 and continued until 1982, was a conversion of a naval reactor project for which funding had been canceled. Some observers believe this early technology decision was largely responsible for the industry’s problems in later years.

Another US nuclear power plant that began operations in 1957, the Vallecitos plant near Pleasanton, California, was a research and development facility that became the first privately owned and operated nuclear power plant to provide significant quantities of electricity to a public utility grid. The Vallecitos facility employed a boiling-water reactor, a type of reactor in which the light water surrounding the enriched uranium fuel is converted directly into steam. The steam is piped to a turbine, which rotates to power an electric generator that produces electricity. The Vallecitos reactor was shut down in 1963. Approximately one-third of the commercial nuclear reactors operating in the United States are boiling-water reactors.

Yet another technology emerged in the postwar years. Beginning in 1946, the United States developed a series of experimental prototype breeder reactors, a type of nuclear reactor in which the reaction is controlled in such a way that more fuel is produced than consumed. In 1963, the first commercial began low-power test operations at the Enrico Fermi Atomic Power Plant in Michigan. An accident in 1966 resulted in a partial core meltdown and caused reactor and fuel assembly damage that took almost four years to repair. Operations resumed in 1970 and continued until the decision was made in 1972 to decommission the reactor.

Twenty- and Twenty-First-Century Developments

Government, industry, and public opinion were all largely positive about nuclear energy up through the late 1960s. Two-thirds of the US commercial reactors operating in 2010 were issued construction permits between 1966 and 1973, a time of great optimism about the technology. During this period, the National Environmental Policy Act of 1969 was enacted, which forced prospective reactor owners to address environmental impacts in plant proposals; the environmental movement arose, beginning with the first Earth Day in 1970; and there was a widespread increase in environmental activism on the part of the public. By the mid-1970s, several widely publicized safety hearings, plant incidents, and government studies had begun to focus public and media attention on nuclear plant regulatory and safety lapses, accident risks, and the problem of nuclear waste disposal. These forces combined to create a sizable antinuclear movement in the United States, which was bolstered by the 1979 accident at the Three Mile Island plant in Pennsylvania.

Although proponents of nuclear power frequently blamed licensing interventions by antinuclear activists for numerous plant cost overruns and delays, most analyses concluded that in the majority of cases other factors, such as capital availability and shifting regulatory requirements, were primarily responsible for a slowdown in the development of nuclear power. By the late 1980s, a decline in the number of plants under construction and a shift of public concern to the threat of the nuclear arms race had begun to reduce the ranks of the antinuclear power movement.

Development of breeder reactor technology in particular slowed significantly in the United States during the late twentieth century. One reason for the decline was the unique safety challenges presented by breeder reactors. Unlike light-water reactor systems, fast-neutron breeder reactors employ molten sodium as a coolant. Sodium burns when exposed to air and reacts explosively with water. Economic considerations also put breeder reactors at a disadvantage. As long as uranium supplies remained abundant, light-water reactor facilities were the more competitive option. Finally, the quantities of plutonium that could be created in breeder reactors raised concerns that the material could be used for nuclear weapons applications. The threat of nuclear proliferation led to a directive from President Jimmy Carter in 1977 that indefinitely deferred commercial reprocessing of spent nuclear fuel and plutonium recycling. This effective ban severely curbed breeder reactor progress in the United States. Congressional funding continued for a demonstration breeder plant in Oak Ridge, Tennessee, despite Carter’s opposition, but in 1983 Congress cut funding for the project, which effectively ended the country’s breeder reactor development for the rest of the century.

Between 1987 and 1994, nuclear power proponents won long-sought changes in regulations governing emergency planning requirements, the licensing of new reactors, siting, and reactor design certification. The essence of these changes was to facilitate the process for approving new reactors while sharply reducing opportunities for public participation in the regulatory process. Nuclear opponents adamantly opposed many of these changes, especially a 1992 congressional decision authorizing the US Nuclear Regulatory Commission (NRC)—the federal agency responsible for nuclear power licensing and safety regulation—to forgo a long history of issuing separate licenses for construction and operation, each of which allowed for hearings. Instead, Congress mandated the issuance of a single combined license for both activities that permits few opportunities for safety challenges after construction has been completed.

In the twenty-first century, the United States became receptive to nuclear power. Among the factors contributing to this renewed interest were the need to meet the nation’s continued growth in demand for electricity, the rising prices of fossil fuels, worries over possible interruptions in oil and gas availability, particularly from Middle Eastern sources, and concerns regarding the impact of the burning of fossil fuels on air quality and the global climate. Some environmentalists touted nuclear power as a clean-air, carbon-free technology.

In the United States, nuclear power plants contributed approximately 18 percent of the electricity generated in 2022. As of 2024, there were 54 nuclear plants in the country, with 94 nuclear power reactors in twenty-eight states. Illinois had 11 reactors, more than any other state.

The nation's FY2025 budget request included $1.6 billion for the Office of Nuclear Energy (NE) and $694.2 million for research and development to advance technologies related to reactors and fuel. The budget request also included $188 million for high-assay low-enriched uranium (HALEU) for a research project. According to the budget request, $142.5 million was allotted to support five advanced reactor projects supported by the Department of Energy's Advanced Reactor Demonstration Program. About $32 million was requested to advance the use of digital tools such as artificial intelligence (AI) to develop manufacturing methods to strengthen nuclear supply chains and optimize the performance of nuclear reactors.

Status and Projections: World

As of May 2024, 440 nuclear reactors were in thirty-two countries throughout the world, with the United States having the most, 94 nuclear reactors. These nuclear plants provided about 10 percent of the world's electricty. The five countries with the largest number of reactors were the United States (94), China (56), France (56), Russia (36), and Japan (33). As of 2022, about 60 reactors were in construction in sixteen countries, with an additional 110 planned. However, these new nuclear plants were largely replacing old plants that were being retired.

Nearly 70 percent of the world's reactors are pressurized water reactors (PWR). These reactors have a primary cooling circuit that flows to the reactor's core and a second circuit that generates steam to drive the turbine. Water in the first circuit does not boil because it causes pressure within the reactors. The second-most common type of nuclear reactor is the boiling water reactor (BWR). It has only one circuit that allows water to boil, with the steam being fed directly to the turbine. Some reactors are pressurized heavy water reactors (PHWRs) that use heavy water, a different form, to cool and control nuclear reactions.

Waste- and Contamination-Related Issues

Spent fuel and high-level radioactive waste can pose threats to human health and the environment for many thousands of years, so they must be properly isolated and secured. Deep subterranean storage appears to be the best solution, but finding a repository site with the right geological characteristics is a technical challenge that is invariably complicated by political controversy. In the United States, Congress designated Yucca Mountain, Nevada, as the nation’s sole repository in 1987, and site suitability studies were conducted at Yucca Mountain for nearly two decades. Opponents, including the state of Nevada, charged that the DOE’s studies were geared more toward preparing the site for operation than for objectively assessing its suitability. The DOE submitted its license application for the repository in 2008, ten years after the original target date for opening. In early 2010, under the Obama administration, funding for the site was cut, and the DOE withdrew its license application. Lawsuits have been filed to challenge Yucca Mountain’s closure, which leaves high-level waste in temporary storage at nuclear facilities around the country.

Some countries—notably France, England, Russia, Japan, and India—reprocess spent fuel from nuclear reactors. Reprocessing strips the waste of uranium and plutonium, which can be used to fuel reactors. While reprocessing results in a small reduction of high-level nuclear wastes, it generates large volumes of low-level nuclear wastes, which also require environmentally responsible disposal. Reprocessing is more costly than the single use and disposal of spent fuel. Also, because it creates stockpiles of plutonium, reprocessing has the potential to contribute to nuclear weapons proliferation and terrorism. Separating plutonium from more highly radioactive spent fuel assemblies makes it easier for it to be stolen. With this danger in mind, President Jimmy Carter issued an executive order in 1977 that indefinitely deferred US reprocessing of spent nuclear reactor fuel.

Concern about nuclear power plant accidents continues to trouble the public. Precise accident probability estimates are impossible to derive, given the complexity of nuclear reactor systems. Industry proponents point to several government-sponsored studies that have concluded that the probability of a plant accident with off-site consequences is extremely low. Critics have countered that these studies were methodologically flawed, omitted important factors, and underestimated the true risks. They also emphasize the catastrophic consequences that could result if a low-probability accident should nonetheless occur. During Russia's invasion of Ukraine, drones struck the Zaporizhzhia Nuclear Power Plant, the largest in Europe. Russia claimed that it was not responsible for the attack, which Ukraine considered an act of terrorism. The damage caused by the drones did not affect human safety.

Arguments Pro and Con

Nuclear proponents cite several points in the technology’s favor: a good safety record, improved operating performance since the Three Mile Island accident, studies concluding that the risk of a severe accident is low, and the fact that nuclear power plants emit no significant amounts of common air pollutants or gases that contribute to global warming. Critics of nuclear power point to the long-standing failure of any country to establish a site for the permanent disposal of spent fuel and high-level wastes; flaws, uncertainties, and omissions in accident probability studies; the catastrophic consequences that could result from a severe reactor accident; a large number of safety-related incidents and near accidents; and the high cost of nuclear plants compared to competing electricity-generating technologies and energy-efficiency improvements. In addition, for those countries that do not already have nuclear weapons arsenals, inherent proliferation risks are associated with nuclear power technology and fuels, which, if misused, could provide the expertise, infrastructure, and basic materials for a program to develop nuclear weapons.

Public opinion surveys in the United States after the events at Three Mile Island showed a growing majority opposing the construction of new nuclear power plants. Numerous influential policy assessments from the late twentieth century concluded that it was unlikely that new nuclear power plants would be built in the United States unless the key issues of waste disposal, costs, safety, and public acceptance were satisfactorily resolved. Although the situation differs from country to country, some combination of these factors served to hamper the growth of nuclear power in most countries during the late twentieth century. In the United States, additional factors that contributed to nuclear power’s decline during the 1980s and 1990s included unexpectedly plentiful supplies of natural gas and slower-than-anticipated growth in electricity demand.

The public’s mistrust of nuclear power is generally acknowledged as a roadblock to new plant orders. Risk perception studies have shown that the public’s lack of trust is deeply rooted, widely felt, and resistant to change. Surveys assessing public support in the United States for the use of nuclear power reflected a decline between 1994, when 57 percent of those polled were in favor, and 2001, when 46 percent were in favor. Since 2001, however, support has increased, reaching 57 percent in 2023. Concerns about such environmental problems as greenhouse gas emissions and the cost and availability of fossil fuels played a role in this upswing in nuclear power’s popularity. NRC officials and others have noted that, regardless of one’s explanation of the public’s views, public acceptance plays an important role in determining whether new plants will be built in the United States.

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