Advanced Nuclear & Fusion

After more than four decades of work on radioactivity and the new nuclear physics describing atomic components, fission was identified in 1938. It was soon realised that neutrons released by a fissioning nucleus could induce further fissions, opening the possibility of a self-sustaining chain reaction. This is the foundational discovery on which all nuclear power rests.

Confirmation in 1939 that neutrons from fission could induce fission in nearby nuclei established that a chain reaction was physically achievable. Researchers in many countries then petitioned their governments for support, on the cusp of the Second World War, with the aim of developing a nuclear weapon. This converted a laboratory finding into a state-funded technological programme.

Manhattan Project researchers brought Chicago Pile-1 to criticality beneath the Stagg Field stadium at the University of Chicago on 2 December 1942, the first human-made nuclear reactor. The graphite pile proved that a chain reaction could be started, controlled and stopped, and led on to larger single-purpose production reactors for weapons-grade plutonium. It is the foundational demonstration behind every power reactor built since.

The Trinity test in July 1945 was followed a month later by the atomic bombings of Hiroshima and Nagasaki. The military origin of nuclear technology shaped the secrecy, regulation and public perception that would surround civil nuclear power for decades.

On 20 December 1951 the EBR-I station near Arco, Idaho produced about 100 kW of electricity, the first ever generated by a nuclear reactor. It demonstrated that fission heat could be converted into usable electric power. The event marks the practical birth of nuclear electricity generation.

The address reoriented nuclear technology away from wartime secrecy toward international civilian cooperation, setting in motion the negotiations that created the International Atomic Energy Agency and the technology-sharing agreements behind many national power programmes.

The Act allowed rapid declassification of US reactor technology and encouraged development by the private sector. It converted a state monopoly on nuclear knowledge into a commercially exploitable industry, enabling the spread of American reactor designs.

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 for submarines. That choice made the PWR the dominant reactor type for civilian electricity generation as well. Naval propulsion thus set the technological template for the world's power reactor fleet.

On 27 June 1954 the Obninsk Nuclear Power Plant near Moscow became the world's first nuclear power plant to supply electricity to a grid, with the small graphite-moderated reactor giving a modest but continuous output of around 5 MW electrical. It marked the first occasion on which nuclear fission produced electricity for civilian use anywhere in the world, proving that fission could serve public electricity supply rather than only experiments or propulsion.

Calder Hall at Windscale in England was connected to the British national grid on 27 August 1956, becoming the world's first commercial nuclear power station and the first to supply electricity at industrial scale. Its four gas-cooled reactors demonstrated that fission could be harnessed for civilian electricity generation, though like other generation I reactors they had the dual purpose of producing plutonium-239 for Britain's nascent weapons programme.

Created within the United Nations system to promote peaceful nuclear technology and verify that it was not diverted to weapons use, the agency became the central institution of civil nuclear governance and safety standard-setting.

Both the Kyshtym disaster in the USSR and the Windscale fire in the UK occurred in 1957. They were the first major accidents of the nuclear age and established radiological accident risk as an intrinsic feature of the capability.

Controlled fusion reactors have been operated since 1958, following theoretical and experimental investigation begun in the 1950s. None has yet generated net power, and commercial availability is not expected in the near future. Fusion remains the long-horizon branch of nuclear energy capability.

The SL-1 accident in 1961 was the first major accident at a nuclear reactor in the USA. Early accidents of this kind fed the emerging safety and regulatory apparatus around reactors.

Total global installed nuclear capacity rose relatively quickly from less than 1 gigawatt in 1960 to 100 GW by the late 1970s. This first wave of build-out established nuclear power as a mainstream source of grid electricity in industrial economies.

The treaty separated civil nuclear energy from weapons proliferation in international law, obliging non-weapons states to accept safeguards inspections in exchange for access to peaceful nuclear technology, a bargain still underpinning today's civil power sector.

By the mid-1970s opposition had gained wide appeal, with the debate reaching an intensity described as unprecedented in the history of technology controversies. Increased hostility lengthened licensing, multiplied regulations and raised safety equipment requirements, making construction far more expensive. In the United States over 120 reactor proposals were eventually cancelled.

Countries that had relied heavily on oil for electricity responded to the oil shock by investing in nuclear power. France built 25 nuclear power plants over the following 15 years, and by 2019 derived 71% of its electricity from nuclear, the highest share of any nation. Energy security, not climate, was the original driver of the largest national nuclear programme.

Adopted after the oil price shock exposed France's energy dependence, the programme committed the state utility to a standardised reactor build-out that made France the world's most nuclear-reliant major economy within two decades.

Large protests in the early 1970s against a proposed plant at Wyhl led to the project's cancellation in 1975. The success at Wyhl inspired opposition movements elsewhere in Europe and North America. It marked the point at which public opposition became a decisive constraint on nuclear deployment.

La Hague has operated commercially since 1976 and by 2010 accounted for half the world's reprocessing. Reprocessing capability allows recovery of usable material from spent fuel and is concentrated in very few countries.

The 1979 partial meltdown at Three Mile Island in Pennsylvania, rated INES level 5, caused no fatalities and was smaller in scale than later disasters, but it ended new commercial reactor orders in the United States for more than three decades and played a major part in reducing new plant construction in many other countries. It drove increased regulation and reshaped public and regulatory attitudes toward nuclear safety across the West.

Liberalization in the United States during the 1980s and in Europe during the 1990s disadvantaged nuclear plants, which have high capital but low operating costs, relative to natural gas plants that were faster to build and faced little political opposition. Together with rising construction costs and falling fossil fuel prices, this stalled new orders. Market structure thus became as important as technology in determining nuclear capability.

During the 1980s a new nuclear reactor started up every 17 days on average, and global installed capacity reached 300 GW by the end of the decade. This was the peak growth phase of the industry; from the late 1980s new capacity additions slowed sharply, reaching only 365 GW by 2005.

The 1986 Chernobyl disaster, involving an RBMK reactor in Soviet Ukraine, was the worst civil nuclear accident in history in both casualties, with 56 direct deaths, and cost, estimated at 18 billion roubles. The reactor explosion and fire spread radioactive contamination across large parts of Europe and forced the permanent evacuation of a surrounding exclusion zone. It altered the development of nuclear power, greatly reduced new plant construction in the following years, and became the defining reference point for nuclear safety regulation for a generation.

WANO was founded to promote safety awareness and the professional development of operators in nuclear facilities worldwide. Its creation institutionalised transnational operator-level safety learning, a capability that had not previously existed.

A 1987 referendum, influenced by Chernobyl, rejected nuclear power, and Italy completed its phase-out in 1990. It was the first major economy to abandon the capability entirely, establishing the precedent of democratic reversal of a national nuclear programme.

The updated Strategic Energy Plan dropped earlier language committing to reduce dependence on nuclear power, instead backing reactor restarts and replacement builds at existing sites as part of a broader post-Fukushima policy reversal.

The budget announcement set a target of 100 gigawatts of nuclear capacity by 2047 and proposed amending liability law to draw private and foreign capital into a sector that had long been reserved for the state.

The Experimental Advanced Superconducting Tokamak in Hefei held a steady-state, high-confinement plasma for more than seventeen minutes, a new world record and a step toward the longer confinement times a power-generating fusion plant would need.

The National Assembly voted to resume a programme first approved in 2009 and shelved in 2016 after the Fukushima accident dampened public support, restarting site preparation with foreign technology partners still to be finalised.

The reactor began supplying power more than a decade behind schedule and several times over budget, closing out Europe's most troubled recent nuclear construction project as the unit moved toward full commercial operation.

A nationwide vote produced a clear majority in favour of construction at Ulken on Lake Balkhash, ending years of hesitation in a country that mines large amounts of uranium but has never generated nuclear power.

A long-term power purchase agreement with Microsoft underpinned plans to bring the undamaged Unit 1, closed since 2019, back into service under the name Crane Clean Energy Center, the first US commitment to revive a shuttered commercial reactor.

Europe's largest nuclear station, seized early in the war, was cut off from off-site power supply on several occasions, forcing reliance on emergency diesel generators and prompting renewed international warnings about the risk of an accident.

The deal, South Korea's largest reactor export to date, was won against French competition and extended the reach of the APR1400 design beyond South Korea and the United Arab Emirates into central Europe.

The small experimental unit in the Gobi desert, brought to criticality in 2023 as the first thorium reactor to run since an American trial decades earlier, demonstrated on-power refuelling, a capability central to the design's promise of near-continuous operation.

Recipients included Commonwealth Fusion Systems and Tokamak Energy Inc, with the aim of enhancing and accelerating fusion energy development. As of 2020, more than 80 years after the first attempts, commercialisation of fusion power was thought unlikely before 2050.

While Russian oil and gas faced international sanctions after the full-scale invasion of Ukraine, the state nuclear company Rosatom was not targeted. As of 2023 Rosatom was building nuclear plants around the world, giving Russia unusual leverage over other states' nuclear capability.

The Department of Energy, working with commercial partners, aimed to build two different advanced reactor designs by 2027 as part of longer-term green energy and energy security goals. It marked renewed American state support for reactor innovation after decades of stagnation.

With world oil and gas prices rising, Macron placed nuclear at the heart of France's drive for carbon neutrality by 2050. Several other countries simultaneously announced plans to reinvigorate ageing nuclear capacity with new investment.

In 2022 Kishida announced the reopening of ten more nuclear plants and, in July, said Japan should consider building advanced reactors and extending operating licences beyond 60 years. His aim was to shield consumers from fossil fuel price volatility, cut emissions, and make Japan a significant exporter of nuclear energy and technology to developing countries.

The plan, prepared by the Agency for Natural Resources and Energy with an advisory committee and following public consultation, set a nuclear target requiring the restart of another ten reactors. It formalised nuclear's return to Japanese energy planning a decade after Fukushima.

Interest grew on the expectation that smaller reactors would allow faster deployment, lower financing costs during construction and cheaper high-volume factory manufacture of components, offsetting the economies of scale of large reactors. In 2026 Natixis Corporate and Investment Banking reported that the SMR sector remained far from commercial reality and was entering a phase where engineering ambition must confront regulatory complexity, financing realities and industrial execution.

China had 45 reactors in operation, 13 under construction and plans for 43 more, which would make it the world's largest nuclear generator. Nuclear supplied only 5% of Chinese electricity in 2019, leaving substantial room for growth. Most reactors under construction worldwide are now generation III units in Asia.

The deep geological repository at the Olkiluoto Nuclear Power Plant was under construction as of 2015. Permanent disposal capability addresses one of the principal objections to nuclear power, and very few countries have advanced this far.

By 2015 the agency recognised the importance of low-carbon generation for mitigating climate change in its nuclear outlook. At the time the global trend was for new stations coming online to be balanced by retirements of old plants.

From 2015 Japan started restarting the remaining 40 reactors following safety checks and revised operating criteria requiring public approval. The restart process showed how a large nuclear nation could rebuild the capability after political rupture.

On 11 March 2011 the Fukushima Daiichi plant lost electricity supply to its emergency cooling system after one of the largest earthquakes ever recorded and the ensuing tsunami disabled backup cooling, causing three reactor meltdowns, mass evacuation and the most serious civilian nuclear accident since Chernobyl. Japan shut down its entire reactor fleet, some units permanently, while the disaster delayed the anticipated nuclear renaissance, drove Germany's decision to phase out nuclear power entirely, and prompted re-examination of reactor safety and energy policy worldwide.

Following Fukushima, Germany decided on a complete nuclear phase-out, and many other countries reviewed their programmes. The decision removed one of Europe's largest nuclear fleets and shifted the continent's generation mix. By 2022 Germany was restarting coal plants to cover the loss of Russian gas supporting its Energiewende.

The Phénix fast breeder reactor was shut down in 2009. Its closure narrowed the field of operating breeder reactors, a technology which could extend uranium resources enormously but which remains economically constrained by reprocessing costs.

Construction started in 2007 but the project has suffered many delays and budget overruns, with operations now not expected before 2034. ITER represents the principal international attempt to demonstrate net fusion power at scale.

Concerns about carbon dioxide emissions raised expectations of a new wave of reactor construction in the early 2000s. Newer generation III designs such as the EPR began construction during this period. The renaissance reframed nuclear power as a climate technology.