Nuclear Generation

The splitting of heavy nuclei by neutron bombardment was identified in 1938, following decades of work on radioactivity and the new nuclear physics of atomic structure. It was quickly realised that neutrons released by a fissioning nucleus could induce further fissions, opening the possibility of a self-sustaining chain reaction. This discovery is the foundation of all nuclear generation.

Confirmation that fission neutrons could induce further fissions came in 1939, on the cusp of the Second World War. Scientists in many countries then petitioned their governments for research support, initially with nuclear weapons in view. This mobilisation created the state-funded research base from which civil reactors later emerged.

On 2 December 1942 the first human-made nuclear reactor achieved criticality beneath the Stagg Field stadium, as part of the Allied atomic bomb effort. It led to larger single-purpose production reactors for weapons-grade plutonium. Reactor physics demonstrated here underpinned all later power reactors.

The United States tested the first nuclear device in July 1945, with the atomic bombings of Hiroshima and Nagasaki following a month later. The military origin of reactor technology shaped the secrecy, regulation and public perception of nuclear generation for decades. Civil power emerged as a by-product of this weapons programme.

On 20 December 1951 the EBR-I experimental reactor produced about 100 kW, the first electricity ever generated by nuclear fission. It demonstrated that reactor heat could be converted to useful power. This was the proof of concept behind the optimism of the 1940s and 1950s that nuclear power could be cheap and endless.

Eisenhower urged the rapid development of peaceful uses of nuclear energy before the UN General Assembly. The speech reframed reactor technology as a civil as well as military capability and spurred international cooperation and technology transfer. It set the political framework within which civil nuclear programmes spread.

The Act permitted rapid declassification of US reactor technology and encouraged private-sector development. It converted a state weapons monopoly into the legal basis for a commercial nuclear industry. The resulting diffusion of American designs shaped reactor fleets worldwide.

The Navy was the first organisation to develop practical nuclear power, choosing a pressurised water design because it was simpler, more compact and easier to operate in a submarine. Nautilus went to sea in January 1954. The choice made the PWR the dominant reactor type for civilian electricity generation thereafter.

On 27 June 1954 Obninsk began delivering around 5 MW of electric power to the Soviet grid. It was the first time reactor output was used for public electricity supply rather than experiment. The achievement marked the Soviet Union as an early leader in civil nuclear generation.

Calder Hall was connected to the British national grid on 27 August 1956. Like other generation I plants it served a dual purpose, producing electricity and plutonium-239 for Britain's nascent weapons programme. It established the commercial-scale template for national nuclear programmes.

The Kyshtym disaster in the Soviet Union and the Windscale fire in the United Kingdom both occurred in 1957. They were the first major accidents of the nuclear age and revealed the radiological hazards inherent in reactor and fuel-cycle operations. Safety practice and public perception of nuclear generation were shaped by such events.

Reactors producing controlled fusion power have been operated since 1958, following theoretical and experimental investigation starting in the 1950s. None has yet generated net power. Fusion remains a prospective rather than realised generation capability.

Total global installed nuclear capacity rose from less than 1 GW in 1960 to 100 GW by the late 1970s. The rapid build-out reflected state-backed programmes and optimism about cheap nuclear electricity. It established nuclear generation as a mainstream grid technology.

The SL-1 accident in 1961 was the first major accident at a nuclear reactor in the USA. It contributed to the growing awareness of reactor safety risks. Local opposition to nuclear power also began emerging in the United States in the early 1960s.

The oil crisis pushed countries that relied heavily on oil for electricity, notably France and Japan, towards nuclear power. France built 25 nuclear power plants over the following 15 years. By 2019 nuclear supplied 71% of French electricity, the highest share of any nation.

Large protests in the early 1970s against a planned plant at Wyhl ended with the project's cancellation in 1975. The success inspired opposition movements elsewhere in Europe and North America. Public hostility lengthened licensing, added regulation and raised construction costs across the industry.

La Hague has operated commercially since 1976 and accounted for half the world's reprocessing as of 2010. More than 32,000 tonnes of spent fuel had been reprocessed by 2015, mostly French with 17% German and 9% Japanese. Reprocessing capability is a distinct national competence within the nuclear fuel cycle.

The 1979 accident at Three Mile Island was a smaller-scale event than later disasters but had outsized consequences. It played a major part in reducing new plant construction in many countries and intensified regulation and public opposition. Over 120 US reactor proposals were ultimately cancelled.

Electricity liberalisation in the US during the 1980s and Europe in the 1990s disadvantaged plants with high capital and low operating costs. Natural gas plants faced little political opposition, were faster to build and enjoyed low fuel prices. The shift halted new nuclear ordering in liberalised markets.

As of 2023 the Russian state nuclear company Rosatom was building nuclear plants around the world. Although Russian oil and gas were sanctioned after the full-scale invasion of Ukraine in February 2022, Rosatom was not targeted. This left reactor export capability concentrated in a geopolitically contested supplier.

In 2023 the DOE awarded funding to eight companies including Commonwealth Fusion Systems and Tokamak Energy to accelerate fusion energy development. The grants marked a shift towards private-sector fusion alongside large intergovernmental projects. Commercialisation was still thought unlikely before 2050.

With world energy prices rising in 2022, many countries announced plans to reinvigorate ageing nuclear capacity. President Macron announced six new French reactors, placing nuclear at the heart of France's drive for carbon neutrality by 2050. The US Department of Energy, with TerraPower and X-energy, planned two different advanced reactors by 2027.

In October 2021 the cabinet adopted the plan prepared by the Agency for Natural Resources and Energy following public consultation. The 2030 nuclear target depends on restarting another ten reactors. In July 2022 Prime Minister Kishida said Japan should also consider advanced reactors and licence extensions beyond 60 years.

Interest in SMRs grew enormously during the 2020s on expectations of faster deployment, lower financing costs and cheaper factory manufacture of smaller components. In 2026 Natixis Corporate and Investment Banking reported the sector was still far from commercial reality, facing regulatory complexity, financing realities and industrial execution. SMRs represent the principal hoped-for route to restoring nuclear cost competitiveness.

In January 2019 China had 45 reactors in operation, 13 under construction and plans for 43 more. Nuclear supplied only 5% of its electricity in 2019, leaving large room for growth. Most new reactors under construction worldwide are generation III units in Asia.

As of 2017 only two breeder reactors were producing commercial power, both in Russia. Breeder technology uses uranium-238 or thorium rather than the scarce uranium-235, but high reprocessing costs have limited deployment. France's Phénix breeder was powered down in 2009 after 36 years of operation.

By 2015 the IAEA's outlook had become more positive, recognising the importance of low-carbon generation for mitigating climate change. At that point new plants coming online were roughly balanced by retirements of old ones. Climate policy became a principal justification for maintaining the capability.

Japan shut down all its reactors after Fukushima, some permanently, and in 2015 began restarting the remaining 40 following safety checks against revised operating criteria and public approval. The restart process showed how a major nuclear nation could suspend and then rebuild the capability. It became the template for post-accident regulatory reconstruction.

Following Fukushima, Germany legislated a complete nuclear phase-out by 2022, while many other countries reviewed their programmes. The decision removed a large national fleet from the global capacity base. By 2022 Germany was restarting coal plants to cover the loss of Russian gas supporting its Energiewende.

On 11 March 2011 the plant lost electricity supply to its emergency cooling system following one of the largest earthquakes ever recorded, causing three meltdowns. It was the most serious civilian nuclear accident since Chernobyl. The disaster prompted a re-examination of nuclear safety and energy policy in many countries.

Construction of ITER began in 2007 as the flagship international fusion experiment. The project has suffered many delays and budget overruns and is now not expected to begin operations until 2034. Fusion energy is not considered likely to be commercially widespread before 2050.

Concerns about carbon dioxide emissions prompted expectations of renewed reactor construction in the early 2000s. Newer generation III designs such as the EPR began construction in this period. The revival was later delayed by the Fukushima accident.

Nuclear power supplied 16.5% of global electricity in 1997 but only about 9% in 2023, largely because the economics of nuclear power became more difficult. Output in 2023 was 2,602 TWh, the second largest low-carbon source after hydroelectricity. The decline reflects slow new build rather than falling absolute output.

Up to 2005 the programme had processed $8 billion of highly enriched weapons-grade uranium into low-enriched fuel by dilution with natural uranium, equivalent to eliminating 10,000 warheads. For about two decades this material generated nearly 10% of all US electricity, around half of US nuclear output and some 7,000 TWh in total. As of 2013 Russia appeared uninterested in extending the programme.

Influenced by Chernobyl, Italian voters rejected nuclear power in a 1987 referendum. The country completed its phase-out in 1990, the first major economy to abandon the capability entirely. It set a precedent for referendum-driven nuclear exit in Europe.

WANO was established to promote safety awareness and the professional development of operators at nuclear facilities worldwide. Its creation institutionalised cross-border exchange of operating experience. It remains a central body in the international governance of reactor safety.

The 1986 Chernobyl accident caused 56 direct deaths and cleanup costs estimated at 18 billion roubles, around US$68 billion in 2019 terms. It altered the development of nuclear power and forced a greater focus on international safety and regulatory standards. New plant construction fell sharply in the following years.

During the 1980s one new nuclear reactor started up every 17 days on average, and global capacity reached 300 GW by the decade's end. This was the high-water mark of nuclear expansion. New capacity additions slowed sharply thereafter, reaching only 365 GW by 2005.