Nuclear power

Nuclear power is the use of nuclear reactions to produce electricity. This energy comes from the tiny particles inside an atom. There are three main ways to get this power: nuclear fission, nuclear decay, and nuclear fusion. Most electricity today comes from nuclear fission using uranium or plutonium. This process happens in large nuclear power plants.

In nuclear fission, the center of an atom, called the nucleus, splits apart. When this happens, it releases a massive amount of energy. This split also releases tiny particles called neutrons. If these neutrons hit other nearby nuclei, they can cause them to split too. This creates a self-sustaining chain reaction.

Many plants use a design called a pressurized water reactor, or PWR. This design uses water to manage the heat and the reaction. The PWR was originally chosen for submarines because it is compact and simple.

Nuclear power comes in different types based on how the energy is released. Fission is the most common method used for civilian electricity. Nuclear decay is a different process used in niche areas. For example, some space probes like Voyager 2 use radioisotope thermoelectric generators. These use decay to provide power in space.

There is also nuclear fusion. This is when nuclei join together instead of splitting. Scientists have operated fusion reactors since 1958. However, they have not yet reached the point of generating more power than they consume.

The history of this science began with the discovery of fission in 1938. This followed decades of research into radioactivity. In 1942, the first human-made reactor, Chicago Pile-1, reached criticality. This was part of the Manhattan Project in the United States. The first time a reactor produced electricity was in 1951 at the EBR-I station in Idaho.

Later, the Obninsk plant in the USSR joined a power grid in 1954. The first commercial station was Calder Hall in England, which began in 1956.

Nuclear power grew very quickly in the late 20th century. Global capacity reached 100GW in the late 1970s and 300GW by 1990. However, major accidents changed how people viewed this technology. The Three Mile Island accident in 1979 and the Chernobyl disaster in 1986 caused great concern. The Chernobyl accident involved an RBMK reactor and is considered the worst nuclear disaster in history.

These events led to much stricter safety rules and more public opposition. In 2011, the Fukushima Daiichi accident in Japan also caused a re-examination of nuclear safety.

Despite these challenges, nuclear power remains a massive part of the world's energy. There are 416 civilian fission reactors operating globally. These provide about 9% of the world's total electricity, which is 2,602 terawatt hours in 2023. The United States has the largest fleet of reactors. It generates nearly 800TWh per year with a high capacity factor of 92%. The average global capacity factor is 89%.

Nuclear power is often discussed as a sustainable, low-carbon energy source. It emits no greenhouse gases during operation. It also has lower life-cycle carbon emissions than many renewable energy sources. One study suggests that nuclear plants can save 800,000 life years by preventing air pollution. This is because fossil fuels like coal and gas cause more deaths per unit of energy through pollution.

However, the anti-nuclear movement still focuses on the risks of radiation and the cost of building new plants.