A nuclear power phase-out is the discontinuation of usage of nuclear power for energy production. Often initiated because of concerns about nuclear power, phase-outs usually include shutting down nuclear power plants and looking towards fossil fuels and renewable energy. Three nuclear accidents have influenced the discontinuation of nuclear power: the 1979 Three Mile Island partial nuclear meltdown in the United States, the 1986 Chernobyl disaster in the USSR (now Ukraine), and the 2011 Fukushima nuclear accident in Japan.

, only two countries have permanently closed all of their formerly-functioning nuclear plants and have no active plans to restart or replace them: Lithuania in 2009 and Germany by 2023. , a nuclear power phase-out is underway in Spain.

Italy and Kazakhstan both completed nuclear power phase-outs, but have subsequently announced plans to build new nuclear power plants. Armenia shut down its only nuclear plant but subsequently restarted it. Taiwan shut down all of its nuclear plants, but subsequently announced plans to restart several of them. Austria never used its first nuclear plant that was completely built. Cuba, Libya, North Korea and Poland never completed the construction of their first nuclear plants due to financial, political and technical reasons.Erika Simpson and Ian Fairlie, Dealing with nuclear waste is so difficult that phasing out nuclear power would be the best option, Lfpress, 26 February 2016.

Nuclear shut-downs after Fukushima have significantly set back emissions reductions goals in several countries. A 2019 study of the impacts of the German and Japanese closures concludes that by continuing to operate their nuclear plants "these two countries could have prevented 28,000 air pollution-induced deaths and 2400 Mt emissions between 2011 and 2017. By sharply reducing nuclear instead of coal and gas after Fukushima, both countries lost the chance to prevent very large amounts of air pollution-induced deaths and emissions".

Several countries formerly opposed to opening nuclear programs or planning phaseouts have reversed course in recent years due to climate concerns and energy independence including Belgium, the Philippines, Greece, Sweden and South Korea.

Overview

A popular movement against nuclear power exists in the Western world, based on concerns about more nuclear accidents and concerns about nuclear waste. Anti-nuclear critics see nuclear power as a dangerous, expensive way to boil water to generate electricity.Helen Caldicott (2006). Nuclear Power is Not the Answer to Global Warming or Anything Else, Melbourne, Australia: Melbourne University Press, , p. xvii. The 1979 Three Mile Island accident and the 1986 Chernobyl disaster played a key role in stopping new plant construction in many countries. Major anti-nuclear power groups include Friends of the Earth, Greenpeace, Institute for Energy and Environmental Research, Nuclear Information and Resource Service, and Sortir du nucléaire (France).

Several countries, especially European countries, have abandoned the construction of new nuclear power plants.Netherlands: Court case on closure date Borssele NPP, article from anti-nuclear organization (WISE), dated 29 June 2001. Austria (1978), Sweden (1980) and Italy (1987) voted in referendums to oppose or phase out nuclear power, while opposition in Ireland prevented a nuclear program there. Countries that have no nuclear plants and have restricted new plant constructions comprise Australia, Austria, Denmark, Greece, Italy, Ireland, Norway and Serbia.Nuclear Power in the World Energy Outlook , by the Uranium Institute, 1999.Anti-nuclear resolution of the Austrian Parliament , as summarised by an anti-nuclear organisation (WISE). Poland stopped the construction of a plant.Nuclear news from Poland , article from the Web site of the European Nuclear Society, April 2005. Belgium, Germany, Spain, and Sweden decided not to build new plants or intend to phase out nuclear power, although still mostly relying on nuclear energy.Germany Starts Nuclear Energy Phase-Out, article from Deutsche Welle, 14 November 2003.

New reactors under construction in Finland and France, which were meant to lead a nuclear new build, have been substantially delayed and are running over-budget.James Kanter. In Finland, Nuclear Renaissance Runs Into Trouble The New York Times, 28 May 2009.James Kanter. Is the Nuclear Renaissance Fizzling? Green, 29 May 2009.Rob Broomby. Nuclear dawn delayed in Finland BBC News, 8 July 2009. Despite these delays the Olkiluoto reactor is now online and delivering low-emissions power to the grid as of 12 March 2022. "When Olkiluoto 3 reaches full output, around 90% of Finland's electricity generation will come from clean, low-carbon electricity sources, with nuclear generation supplying around half of that." In addition, China has 11 units under construction and there are also new reactors being built in Bangladesh, Belarus, Brazil, India, Japan, Pakistan, Russia, Slovakia, South Korea, Turkey, United Arab Emirates, United Kingdom and the United States of America. At least 100 older and smaller reactors will "most probably be closed over the next 10–15 years".

Countries that wish to shut down nuclear power plants must find alternatives for electricity generation; otherwise, they are forced to become dependent on imports. Therefore, the discussion of a future for nuclear energy is intertwined with discussions about fossil fuels or an energy transition to renewable energy.

Countries that have decided on a phase-out

The following countries either have a formal nuclear power phase-out underway, or have completed a phase-out, and there are, , no known plans to reverse that policy or recommence nuclear power generation:

Germany

Status: Phase-out complete

In 2000, the First Schröder cabinet, consisting of the SPD and Alliance '90/The Greens, officially announced its intention to phase out the use of nuclear energy. The power plants in Stade and Obrigheim were turned off on 14 November 2003, and 11 May 2005, respectively. The plants' dismantling was scheduled to begin in 2007.

The Renewable Energy Sources Act, passed in 2000, provided for a feed-in tariff in support of renewable energy. The German government, declaring climate protection as a key policy issue, announced a carbon dioxide reduction target by the year 2005 compared to 1990 of 25%. In 1998, the use of renewables in Germany reached 284 PJ of primary energy demand, which corresponded to 5% of the total electricity demand. By 2010, the German government wanted to reach 10%; in fact, 17% were reached (2011: 20%, 2015: 30%).

Anti-nuclear activists argued the German government had been supportive of nuclear power by providing financial guarantees for energy providers. Also, there were, as yet, no plans for the final storage of nuclear waste. By tightening safety regulations and increasing taxation, a faster end to nuclear power could have been forced. A gradual closing of nuclear power plants had come along with concessions in questions of safety for the population with transport of nuclear waste throughout Germany. Kommunikation Wissenschaft This latter point was disagreed with by the Minister of Environment, Nature Conservation and Nuclear Safety.

In 2005, critics of a phase-out in Germany argued that the grid energy contribution from the nuclear power stations may not be adequately compensated in the short term, possibly causing an energy crisis. They also predicted that only coal-powered plants could compensate for nuclear power in general, and that emissions would increase tremendously as a result. A possible mitigating factor would be energy imported from France's lower carbon, (and primarily nuclear), power facilities. Russian natural gas would be an additional, perhaps necessary option. Numerous factors, including progress in wind turbine technology and photovoltaics, reduced the need for conventional alternatives.

In 2011, Deutsche Bank analysts concluded that "the global impact of the Fukushima disaster is a fundamental shift in public perception with regard to how a nation prioritizes and values its population's health, safety, security, and natural environment when determining its current and future energy pathways". There were many anti-nuclear protests and, on 29 May 2011, Angela Merkel's government announced that it would close all of Germany's nuclear power plants by December 2022.

Galvanised by the first anniversary of the Fukushima nuclear accident, anti-nuclear demonstrations were held in Germany in March 2012. Organisers said more than 50,000 people in six regions took part.

The German Energiewende designates a significant change in energy policy from 2010. The term encompasses a transition by Germany to a low carbon, environmentally sound, reliable, and affordable energy supply.

On 6 June 2011, following the Fukushima accident, the government removed the use of nuclear power as a bridging technology as part of their policy.

In September 2011, German engineering giant Siemens announced it would withdraw entirely from the nuclear industry, as a response to the Fukushima nuclear accident in Japan, and said that it would no longer build nuclear power plants anywhere in the world. The company's chairman, Peter Löscher, said that "Siemens was ending plans to cooperate with Rosatom, the Russian state-controlled nuclear power company, in the construction of dozens of nuclear plants throughout Russia over the coming two decades". Also in September 2011, IAEA Director General Yukiya Amano said the Japanese nuclear disaster "caused deep public anxiety throughout the world and damaged confidence in nuclear power".

A 2016 study shows that during the nuclear phaseout, the security of electricity supply in Germany stayed at the same high level compared to other European countries and even improved in 2014. The study was conducted near the halfway point of the phaseout, 9plants having been shut and a further 8 still in operation. This reference provides a good overview of the phaseout.

In early October 2016, Swedish electric power company Vattenfall began litigation against the German government for its 2011 decision to accelerate the phase-out of nuclear power. Hearings took place at the World Bank's International Centre for Settlement of Investment Disputes (ICSID) in Washington, DC and Vattenfall claimed almost €4.7billion in damages. The German government has called the action "inadmissible and unfounded". These proceedings were ongoing in December 2016, despite Vattenfall commencing civil litigation within Germany.

On 5December 2016, the Federal Constitutional Court () ruled that the nuclear plant operators affected by the accelerated phase-out of nuclear power following the Fukushima accident were eligible for "adequate" compensation. The court found that the nuclear exit was essentially constitutional but that the utilities were entitled to damages for the "good faith" investments they made in 2010. The utility companies were authorised to sue the German government under civil law. E.ON, RWE, and Vattenfall were expected to seek a total of €19billion under separate suits. Provides a history of the nuclear exit. Six cases were registered with courts in Germany, .

A scientific paper released in 2019 found that the German nuclear shutdown led to an increase in carbon dioxide emissions around 36.2 megatons per year, and killed 1100 people a year through increased air pollution. As they shut down nuclear power, Germany made heavy investments in renewable energy, but those same investments could have "cut much deeper into fossil fuel energy" if the nuclear generation had still been online.