Nuclear power

Nuclear power is the use of nuclear reactions to make electricity. Today, most nuclear power comes from splitting atoms of uranium and plutonium in special places called nuclear power plants. These plants make a lot of energy without creating smoke or gases that harm our planet.

The first nuclear power plant started working in the 1950s. Many countries built these plants to help provide energy. Even with some worries, nuclear power is seen as a clean energy source because it does not release greenhouse gases that warm the Earth. It also helps by cutting down on air pollution that would happen if we burned coal and other fuels. Today, nuclear power gives about 9% of the world's electricity and is growing, especially in parts of Asia.

History

Main articles: History of nuclear power and Timeline of nuclear power

Origins

The process of nuclear fission was discovered in 1938 after studying radioactivity and learning more about the parts of atoms. Scientists found that tiny particles called neutrons could cause nearby nuclei to split too. This was proven in experiments in 1939.

Soon after, scientists asked their governments for support to study nuclear fission, especially because World War II was beginning. In the United States, this research led to the first human-made nuclear reactor, called the Chicago Pile-1, built under a stadium at the University of Chicago. It began working on December 2, 1942, as part of the Manhattan Project, the effort by the Allied countries to build atomic bombs. This led to building larger reactors to make weapons-grade plutonium for the first nuclear weapons. The United States tested the first nuclear weapon in July 1945, and the atomic bombings of Hiroshima and Nagasaki happened one month later.

Even though the first nuclear devices were for military use, there was hope in the 1940s and 1950s that nuclear power could provide lots of cheap energy. In 1951, electricity was made for the first time by a nuclear reactor at the EBR-I station near Arco, Idaho. In 1953, American President Dwight Eisenhower gave a speech called "Atoms for Peace" at the United Nations, saying that nuclear power should be used for peaceful purposes. This led to the Atomic Energy Act of 1954, which made it easier for private companies to develop nuclear technology.

First power generation

The first group to make practical nuclear power was the U.S. Navy, building the S1W reactor to power submarines and aircraft carriers. The first nuclear-powered submarine, USS Nautilus, went to sea in January 1954. The S1W reactor was a pressurized water reactor, chosen because it was simple, small, and easy to operate—ideal for submarines. This design later became popular for making electricity too.

On June 27, 1954, the Obninsk Nuclear Power Plant in the USSR became the world’s first nuclear power plant to supply electricity to a city. The world’s first commercial nuclear power station, Calder Hall in England, was connected to the power grid on August 27, 1956. Like some other early reactors, it made electricity and plutonium-239 for Britain’s nuclear weapons program.

Expansion and first opposition

The amount of nuclear power around the world grew quickly at first, going from less than 1 gigawatt (GW) in 1960 to 100 GW by the late 1970s. But during the 1970s and 1980s, rising costs, longer building times, and falling prices for oil and gas made new nuclear plants less attractive. In the 1980s in the U.S. and 1990s in Europe, changes in electricity rules made it harder to invest in new nuclear plants.

The 1973 oil crisis made countries like France and Japan decide to invest in nuclear power. France built 25 nuclear plants over 15 years.

Some people began to worry about nuclear power in the early 1960s in the United States. By the late 1960s, scientists were speaking out about concerns including nuclear accidents. In the early 1970s, large protests happened in Wyhl, Germany, against a new nuclear plant, and the project was cancelled in 1975. This led to more opposition to nuclear power across Europe and North America.

Chernobyl and renaissance

During the 1980s, on average a new nuclear reactor started up every 17 days. By the end of the decade, the world had 300 GW of nuclear power. Since the late 1980s, adding new nuclear power slowed down.

The 1986 Chernobyl disaster in the USSR changed how nuclear power developed and led to a stronger focus on safety rules around the world. The disaster led to the creation of the World Association of Nuclear Operators (WANO) to help improve safety in nuclear facilities. The Chernobyl disaster also caused many countries to stop building new nuclear plants.

In the early 2000s, there was hope for a “nuclear renaissance” because of worries about carbon dioxide emissions. During this time, newer generation III reactors, such as the EPR, began to be built.

Fukushima accident

Plans for a nuclear renaissance were delayed by another nuclear accident. In 2011, the Fukushima Daiichi nuclear accident happened after the Tōhoku earthquake and tsunami. The Fukushima Daiichi Nuclear Power Plant had three reactors that melted because the cooling system stopped working when the power went out. This became the worst civilian nuclear accident since Chernobyl in 1986.

The accident led many countries to look again at nuclear safety and plans for nuclear power. Germany decided to close all its nuclear reactors by 2022, and many other countries looked again at their nuclear programs.

In 2022, Japan’s government said it would reopen 10 more nuclear plants since the 2011 accident. Japan hopes to become a big exporter of nuclear energy and technology.

Current prospects

By 2015, international groups saw nuclear energy as important for helping fight climate change because it doesn’t produce carbon dioxide. In 2018, over 150 new nuclear reactors were planned, with 50 being built. In January 2019, China had 45 reactors operating, 13 being built, and plans for 43 more.

In October 2021, Japan’s government approved a new plan for electricity to 2030, which includes restarting ten more reactors. In July 2022, Japan’s leader said the country should think about building advanced reactors.

In 2022, with oil and gas prices rising, many countries made big plans to bring back older nuclear plants and build new ones. The leader of France said he wants to build six new reactors to help France reach carbon neutrality by 2050. In the United States, the Department of Energy is working with companies TerraPower and X-energy to build two new kinds of nuclear reactors by 2027.

Power plants

See also: List of commercial nuclear reactors and List of nuclear power stations

Nuclear power plants make electricity by using heat from splitting atoms. Inside a plant, there is a reactor where this splitting happens. The heat makes steam. The steam turns a turbine, and the turbine spins a generator. The generator makes electricity.

When a tiny particle called a neutron hits the nucleus of atoms like uranium or plutonium, it can split the nucleus. This splitting gives off energy and more neutrons. These new neutrons can split more nuclei. This is called a chain reaction. Control rods help keep the reaction safe by soaking up extra neutrons.

Fuel cycle

Main articles: Nuclear fuel cycle and Integrated Nuclear Fuel Cycle Information System

The nuclear fuel cycle begins with uranium mining. The uranium ore is turned into a compact ore concentrate, called yellowcake (U₃O₈), to make it easier to move. Most reactors need uranium-235, a special kind of isotope of uranium. Natural uranium has only a tiny bit of uranium-235 (about 0.7%). Some reactors can use natural uranium right away, but most need to increase the amount of uranium-235 through a process called uranium enrichment. After enrichment, the uranium is turned into uranium oxide (UO₂), a ceramic, and then made into small fuel pellets that are stacked into fuel rods for use in reactors.

When fuel has been used in a reactor for a while, it has less useful material and more waste products, so it is moved to a special pool where it cools down. After some time, it can be moved to dry storage containers.

Uranium resources

Main articles: Uranium market, Uranium mining, and Energy development § Nuclear

Uranium is a common element in the Earth's crust, found in rocks, dirt, and ocean water. It is usually only mined where it is found in larger amounts. As of 2011, known uranium resources could last for about 70 to 100 years at current use rates.

Most reactors today use only a small part of natural uranium, called uranium-235. New technologies could use much more of the uranium we have, including waste from older reactors. Some ways to get more uranium include using seawater, which contains small amounts of uranium.

Waste

Main article: Nuclear waste

Nuclear power plants create radioactive waste, which can be low-level or high-level. Low-level waste has low radioactivity and includes things like gloves or tools. High-level waste is mostly used fuel from reactors, which is very radioactive and needs careful handling.

High-level waste

Main articles: High-level waste and Spent nuclear fuel

The most important waste from reactors is spent nuclear fuel, which is very radioactive. It is first stored in pools to cool down, and later moved to dry storage containers. Over time, the radioactivity decreases a lot. After many years, it becomes less radioactive than the original uranium ore.

Low-level waste

Main article: Low-level waste

The nuclear industry also creates low-level waste, such as gloves or tools that have small amounts of radioactivity. This waste can often be disposed of like normal trash after the radioactivity levels drop.

Waste relative to other types

See also: Radioactive waste § Naturally occurring radioactive material

In countries with nuclear power, radioactive waste makes up a small part of all industrial waste. Nuclear power actually creates less waste than coal power plants, which release radioactive materials from coal into the air.

Nuclear waste takes up very little space compared to the amount of energy it produces. For example, the waste from a lifetime of energy use for one person would fit in a small container.

Waste disposal

See also: List of radioactive waste treatment technologies

Used fuel is first stored in pools and then often moved to dry storage containers at the power plant. Some places are building deep underground storage sites for long-term disposal.

There are no large underground waste storage sites in use yet, but Finland is building one called the Onkalo spent nuclear fuel repository.

Reprocessing

Main article: Nuclear reprocessing

See also: Plutonium Management and Disposition Agreement

Most reactors use fuel only once because uranium is cheap. However, some places recycle parts of the used fuel to make new fuel. This can reduce waste and make more energy from the same uranium. Recycling used fuel is done in several countries, but not in the United States.

Breeding

Breeding turns non-useful material into fuel that can be used in special reactors called breeder reactors. These reactors can use almost all of the uranium we have, including waste from older reactors. Some countries are building these types of reactors to make better use of our uranium resources.

Another way to get more fuel is by using thorium, which is more common than uranium. Some countries, like India, are working on using thorium as fuel.

Decommissioning

Main article: Nuclear decommissioning

Nuclear decommissioning is the process of taking apart a nuclear facility. After this, the facility no longer needs special safety measures for radiation. This process can be hard and expensive because of the radioactive materials involved. The costs for decommissioning are usually saved up during the time the facility is in use, in a special fund.

Production

Nuclear power is a way to make electricity by using special reactions in tiny parts of atoms. In 2023, nuclear power made about 9% of all the world's electricity. It was the second most used clean energy source after hydroelectric power.

As of November 2024, there are 415 nuclear reactors working around the world, with more being built. The United States makes the most nuclear electricity, while France uses nuclear power for most of its electricity needs. Some ships also use nuclear power to move around. Scientists are studying new ways to use nuclear heat, like making clean water from sea water.

Economics

Main articles: Economics of nuclear power plants, List of companies in the nuclear sector, and cost of electricity by source

Building new nuclear power plants costs a lot of money. It is important to think about how long it takes to build them and how the money is spent. The price of electricity from nuclear power depends on these things.

Studies show that nuclear power can be one of the cheaper ways to make electricity that is always available. Other energy sources like wind and solar can be cheaper, but they do not always work when we need them. Adding costs for things like carbon taxes can make nuclear power more competitive. Some countries, like India and South Korea, have found ways to lower the costs of building nuclear plants. New smaller designs might also help reduce these costs.

Use in space

Nuclear power is used in space with small devices called radioisotope thermoelectric generators. These devices use natural changes in special materials to make energy. They help power space missions and experiments when there is not enough sunlight, like on the Voyager 2 probe. A few space vehicles have also used small nuclear reactors for power. Both splitting atoms and combining atoms could help spacecraft travel faster with less heavy fuel.

Safety

See also: Nuclear safety and security and Nuclear reactor safety system

Nuclear power plants have special safety features because they use powerful materials. These materials can stay hot even after the plant stops working, so plants need special systems to keep them cool. If these systems stop, the materials can become too hot and spread dangerous substances.

Modern nuclear plants are built with safety systems that naturally stop the reaction if things get too hot. There are also special tools that workers can use to stop the reaction if needed. Even if some systems fail, the plant has strong walls to keep dangerous materials from spreading out.

See also: Energy accidents, Nuclear and radiation accidents and incidents, and Lists of nuclear disasters and radioactive incidents

Some serious accidents have happened at nuclear power plants. These accidents are ranked to show how serious they are. The worst accidents happen very rarely and can affect many people and places.

Accidents can cause problems for people who have to leave their homes and can make them feel worried. It is important to learn from these accidents to make nuclear plants safer.

Main articles: Vulnerability of nuclear plants to attack, Nuclear terrorism, and Nuclear safety in the United States

Proliferation

Further information: Nuclear proliferation

See also: Plutonium Management and Disposition Agreement

Nuclear proliferation means when countries get nuclear weapons and materials that they did not have before. This is a worry because the same technology that makes electricity can also make weapons.

Some countries try to share nuclear fuel to help others get energy, but they also try to make sure these countries do not build weapons. For example, Iran’s nuclear program has caused concern. Many countries work together to stop the wrong use of nuclear technology. Programs like the Megatons to Megawatts Program have helped change materials that could be weapons into fuel for power plants, which has reduced the number of nuclear weapons in the world.

Environmental impact

Main article: Environmental impact of nuclear power

Nuclear power is a clean energy source. It does not make much carbon dioxide, which hurts the environment. It also does not need much land to work. But there are some risks. These include accidents, handling radioactive waste safely, and making sure materials are not used for weapons.

Carbon emissions

See also: Life-cycle greenhouse gas emissions of energy sources

Nuclear power is one of the best ways to make electricity without creating harmful gases. It makes very little carbon dioxide compared to other energy sources like coal or natural gas. Since 1970, nuclear power has helped stop a lot of carbon dioxide from going into the air.

Radiation

The natural radiation we get from the Earth is about 2.4 millisieverts each year. Nuclear power plants add a very tiny amount to this, much less than the radiation from coal power plants. The accident at Chernobyl caused higher radiation levels for people nearby, but the rest of the world only had a very small increase that is still getting smaller over time.

Debate

See also: Nuclear energy policy, Pro-nuclear movement, and Anti-nuclear movement

People have different ideas about using nuclear power to make electricity. Some think it is good because it makes less pollution than burning coal or oil. They say it helps keep the air cleaner.

Others worry about safety and cost. They think nuclear power can be risky and expensive. They also worry about how to store the waste safely.

Comparison with renewable energy

See also: Renewable energy debate

To help our planet, we need to use less coal and oil. Some people think nuclear power can help with this, while others think we should use more natural sources like wind and sun.

Nuclear power makes less waste than some renewable sources, but the waste it makes is very dangerous and needs safe storage for a long time. Nuclear power plants are also harder to shut down than wind or solar plants.

Nuclear power could be built up fast to replace coal and oil, but it still needs good planning and support from governments and communities.

Research

Advanced fission reactor designs

Main article: Generation IV reactor

Today's nuclear power plants are mostly second or third generation systems. Scientists are studying advanced generation IV reactors. These new designs aim to improve cost, safety, and waste handling. They could start being built after 2030.

Hybrid fusion-fission

Main article: Nuclear fusion–fission hybrid

Hybrid nuclear power mixes fusion and fission to make energy. This idea started in the 1950s. Once a fusion power plant works well, it could help use up old nuclear waste.

Fusion

Main articles: Nuclear fusion and Fusion power

Nuclear fusion could be safer and create less radioactive waste than today’s nuclear power. It’s very hard to do, and we haven’t built a fusion power plant yet. Scientists have been studying fusion since the 1950s.

One big project is ITER, a large machine called a tokamak being built in France. ITER is supposed to show that fusion can work well enough to make power. After that, there’s a plan for a commercial fusion power plant called DEMO.