Nuclear power plant

A nuclear power plant (NPP),^[1] also known as a nuclear power station (NPS), nuclear generating station (NGS) or atomic power station (APS) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a generator that produces electricity. As of September 2023^[update], the International Atomic Energy Agency reported that there were 410 nuclear power reactors in operation in 32 countries around the world, and 57 nuclear power reactors under construction.^[2][3][4]

Most nuclear power plants use thermal reactors with enriched uranium in a once-through fuel cycle. Fuel is removed when the percentage of neutron absorbing atoms becomes so large that a chain reaction can no longer be sustained, typically three years. It is then cooled for several years in on-site spent fuel pools before being transferred to long-term storage. The spent fuel, though low in volume, is high-level radioactive waste. While its radioactivity decreases exponentially, it must be isolated from the biosphere for hundreds of thousands of years, though newer technologies (like fast reactors) have the potential to significantly reduce this. Because the spent fuel is still mostly fissionable material, some countries (e.g. France and Russia) reprocess their spent fuel by extracting fissile and fertile elements for fabrication into new fuel, although this process is more expensive than producing new fuel from mined uranium.^{[citation needed]} All reactors breed some plutonium-239, which is found in the spent fuel, and because Pu-239 is the preferred material for nuclear weapons, reprocessing is seen as a weapon proliferation risk.

Building a nuclear power plant often spans five to ten years, which can accrue significant financial costs, depending on how the initial investments are financed.^[5] Because of this high construction cost and lower operations, maintenance, and fuel costs, nuclear plants are usually used for base load generation, because this maximizes the hours over which the fixed cost of construction can be amortized.^[6]

Nuclear power plants have a carbon footprint comparable to that of renewable energy such as solar farms and wind farms,^[7][8] and much lower than fossil fuels such as natural gas and coal. Nuclear power plants are among the safest modes of electricity generation,^[9] comparable to solar and wind power plants.^[10]

The first time that heat from a nuclear reactor was used to generate electricity was on December 21, 1951, at the Experimental Breeder Reactor I, powering four light bulbs.^[11][12]

On June 27, 1954, the world's first nuclear power station to generate electricity for a power grid, the Obninsk Nuclear Power Plant, commenced operations in Obninsk, in the Soviet Union.^[13][14][15] The world's first full scale power station, Calder Hall in the United Kingdom, opened on October 17, 1956 and was also meant to produce plutonium.^[16] The world's first full scale power station solely devoted to electricity production was the Shippingport Atomic Power Station in Pennsylvania, United States, which was connected to the grid on December 18, 1957.

Nuclear power plants generate approximately 10% of global electricity, sourced from around 440 reactors worldwide. They are recognized as a significant provider of low-carbon electricity, accounting for about one-quarter of the world's supply in this category. As of 2020, nuclear power stood as the second-largest source of low-carbon energy, making up 26% of the total.^[21] Nuclear power facilities are active in 32 countries or regions,^[22] and their influence extends beyond these nations through regional transmission grids, especially in Europe.^[23]

In 2022, nuclear power plants generated 2545 terawatt-hours (TWh) of electricity, a slight decrease from the 2653 TWh produced in 2021. Thirteen countries generated at least one-quarter of their electricity from nuclear sources. Notably, France relies on nuclear energy for about 70% of its electricity needs, while Ukraine, Slovakia, Belgium, and Hungary source around half their power from nuclear. Japan, which previously depended on nuclear for over a quarter of its electricity, is anticipated to resume similar levels of nuclear energy utilization.^[21][22]

Over the last 15 years, the United States has seen a significant improvement in the operational performance of its nuclear power plants, enhancing their utilization and efficiency, adding the output equivalent to 19 new 1000 MWe reactors without actual construction. In France, nuclear power plants still produce over sixty percent of this country's total power generation in 2022. While a previous goal aimed to reduce nuclear electricity generation share to lower than fifty percent by 2025, this target was postponed to 2035 in 2019 and ultimately discarded in 2023. Russia continues to export the most nuclear power plants in the world, with projects across various countries: as of July 2023, Russia was constructing 19 out of 22 reactors constructed by foreign vendors;^[24] however, some exporting projects were canceled due to the Russian invasion of Ukraine.^[25] Meanwhile, China continues to advance in nuclear energy: having 25 reactors under construction by late 2023, China is the country with the most reactors being built at one time in the world.^[24][26]

The economics of nuclear power plants is a controversial subject, and multibillion-dollar investments ride on the choice of an energy source. Nuclear power stations typically have high capital costs, but low direct fuel costs, with the costs of fuel extraction, processing, use and spent fuel storage internalized costs.^[37] Therefore, comparison with other power generation methods is strongly dependent on assumptions about construction timescales and capital financing for nuclear stations. Cost estimates take into account station decommissioning and nuclear waste storage or recycling costs in the United States due to the Price Anderson Act.

With the prospect that all spent nuclear fuel could potentially be recycled by using future reactors, generation IV reactors are being designed to completely close the nuclear fuel cycle. However, up to now, there has not been any actual bulk recycling of waste from a NPP, and on-site temporary storage is still being used at almost all plant sites due to construction problems for deep geological repositories. Only Finland has an operating repository, therefore from a worldwide perspective, long-term waste storage costs are uncertain.

Construction, or capital cost aside, measures to mitigate global warming such as a carbon tax or carbon emissions trading, increasingly favor the economics of nuclear power. Further efficiencies are hoped to be achieved through more advanced reactor designs, Generation III reactors promise to be at least 17% more fuel efficient, and have lower capital costs, while Generation IV reactors promise further gains in fuel efficiency and significant reductions in nuclear waste.

In Eastern Europe, a number of long-established projects are struggling to find financing, notably Belene in Bulgaria and the additional reactors at Cernavodă in Romania, and some potential backers have pulled out.^[38] Where cheap gas is available and its future supply relatively secure, this also poses a major problem for nuclear projects.^[38]

Analysis of the economics of nuclear power must take into account who bears the risks of future uncertainties. To date all operating nuclear power stations were developed by state-owned or regulated utilities where many of the risks associated with construction costs, operating performance, fuel price, and other factors were borne by consumers rather than suppliers.^[39] Many countries have now liberalized the electricity market where these risks and the risk of cheaper competitors emerging before capital costs are recovered, are borne by station suppliers and operators rather than consumers, which leads to a significantly different evaluation of the economics of new nuclear power stations.^[40]

Following the 2011 Fukushima nuclear accident in Japan, costs are likely to go up for currently operating and new nuclear power stations, due to increased requirements for on-site spent fuel management and elevated design basis threats.^[41] However many designs, such as the currently under construction AP1000, use passive nuclear safety cooling systems, unlike those of Fukushima I which required active cooling systems, which largely eliminates the need to spend more on redundant back up safety equipment.

According to the World Nuclear Association, as of March 2020:

• Nuclear power is cost competitive with other forms of electricity generation, except where there is direct access to low-cost fossil fuels.
• Fuel costs for nuclear plants are a minor proportion of total generating costs, though capital costs are greater than those for coal-fired plants and much greater than those for gas-fired plants.
• System costs for nuclear power (as well as coal and gas-fired generation) are very much lower than for intermittent renewables.
• Providing incentives for long-term, high-capital investment in deregulated markets driven by short-term price signals presents a challenge in securing a diversified and reliable electricity supply system.
• In assessing the economics of nuclear power, decommissioning and waste disposal costs are fully taken into account.
• Nuclear power plant construction is typical of large infrastructure projects around the world, whose costs and delivery challenges tend to be under-estimated.^[42]

The Russian state nuclear company Rosatom is the largest player in international nuclear power market, building nuclear plants around the world.^[43] Whereas Russian oil and gas were subject to international sanctions after the Russian full-scale invasion of Ukraine in February 2022, Rosatom was not targeted by sanctions.^[43] However, some countries, especially in Europe, scaled back or cancelled planned nuclear power plants that were to be built by Rosatom.^[43]

Modern nuclear reactor designs have had numerous safety improvements since the first-generation nuclear reactors. A nuclear power plant cannot explode like a nuclear weapon because the fuel for uranium reactors is not enriched enough, and nuclear weapons require precision explosives to force fuel into a small enough volume to become supercritical. Most reactors require continuous temperature control to prevent a core meltdown, which has occurred on a few occasions through accident or natural disaster, releasing radiation and making the surrounding area uninhabitable. Plants must be defended against theft of nuclear material and attack by enemy military planes or missiles.^[44]

The most serious accidents to date have been the 1979 Three Mile Island accident, the 1986 Chernobyl disaster, and the 2011 Fukushima Daiichi nuclear disaster, corresponding to the beginning of the operation of generation II reactors.

Professor of sociology Charles Perrow states that multiple and unexpected failures are built into society's complex and tightly coupled nuclear reactor systems. Such accidents are unavoidable and cannot be designed around.^[45] An interdisciplinary team from MIT has estimated that given the expected growth of nuclear power from 2005 to 2055, at least four serious nuclear accidents would be expected in that period.^[46] The MIT study does not take into account improvements in safety since 1970.^[47][48]

Nuclear power works under an insurance framework that limits or structures accident liabilities in accordance with the Paris Convention on Third Party Liability in the Field of Nuclear Energy, the Brussels supplementary convention, and the Vienna Convention on Civil Liability for Nuclear Damage.^[49] However states with a majority of the world's nuclear power stations, including the U.S., Russia, China and Japan, are not party to international nuclear liability conventions.

United States

In the United States, insurance for nuclear or radiological incidents is covered (for facilities licensed through 2025) by the Price-Anderson Nuclear Industries Indemnity Act.

United Kingdom

Under the energy policy of the United Kingdom through its 1965 Nuclear Installations Act, liability is governed for nuclear damage for which a UK nuclear licensee is responsible. The Act requires compensation to be paid for damage up to a limit of £150 million by the liable operator for ten years after the incident. Between ten and thirty years afterwards, the Government meets this obligation. The Government is also liable for additional limited cross-border liability (about £300 million) under international conventions (Paris Convention on Third Party Liability in the Field of Nuclear Energy and Brussels Convention supplementary to the Paris Convention).^[50]

The nuclear power debate about the deployment and use of nuclear fission reactors to generate electricity from nuclear fuel for civilian purposes peaked during the 1970s and 1980s, when it "reached an intensity unprecedented in the history of technology controversies," in some countries.^[51]

Proponents argue that nuclear power is a sustainable energy source which reduces carbon emissions and can increase energy security if its use supplants a dependence on imported fuels.^{[52][full citation needed]} Proponents advance the notion that nuclear power produces virtually no air pollution, in contrast to the chief viable alternative of fossil fuel. Proponents also believe that nuclear power is the only viable course to achieve energy independence for most Western countries. They emphasize that the risks of storing waste are small and can be further reduced by using the latest technology in newer reactors, and the operational safety record in the Western world is excellent when compared to the other major kinds of power plants.^{[53][full citation needed]}

Opponents say that nuclear power poses many threats to people and the environment,^{[who?][weasel words]} and that costs do not justify benefits. Threats include health risks and environmental damage from uranium mining, processing and transport, the risk of nuclear weapons proliferation or sabotage, and the problem of radioactive nuclear waste.^[54][55][56] Another environmental issue is discharge of hot water into the sea. The hot water modifies the environmental conditions for marine flora and fauna. They also contend that reactors themselves are enormously complex machines where many things can and do go wrong, and there have been many serious nuclear accidents.^[57][58] Critics do not believe that these risks can be reduced through new technology,^[59] despite rapid advancements in containment procedures and storage methods.

Opponents argue that when all the energy-intensive stages of the nuclear fuel chain are considered, from uranium mining to nuclear decommissioning, nuclear power is not a low-carbon electricity source despite the possibility of refinement and long-term storage being powered by a nuclear facility.^[60][61][62] Those countries that do not contain uranium mines cannot achieve energy independence through existing nuclear power technologies. Actual construction costs often exceed estimates, and spent fuel management costs are difficult to define.^{[citation needed]}

On 1 August 2020, the UAE launched the Arab region's first-ever nuclear energy plant. Unit 1 of the Barakah plant in the Al Dhafrah region of Abu Dhabi commenced generating heat on the first day of its launch, while the remaining 3 Units are being built. However, Nuclear Consulting Group head, Paul Dorfman, warned the Gulf nation's investment into the plant as a risk "further destabilizing the volatile Gulf region, damaging the environment and raising the possibility of nuclear proliferation."^[63]

Nuclear power plants do not produce greenhouse gases during operation. Older nuclear power plants, like ones using second-generation reactors, produce approximately the same amount of carbon dioxide during the whole life cycle of nuclear power plants for an average of about 11g/kWh, as much power generated by wind, which is about 1/3 of solar and 1/45 of natural gas and 1/75 of coal.^[64] Newer models, like HPR1000, produce even less carbon dioxide during the whole operating life, as little as 1/8 of power plants using gen II reactors for 1.31g/kWh.^[65]

However, there are other environmental impacts for nuclear power plants, such as radioactive waste, ionizing radiation, and waste heat. Large-scale atomic power plants might emit waste heat into natural bodies of water, affecting waterborne organisms.^[66] Mining nuclear fuel, including uranium or thorium, might negatively influence the environment near the mining site.^[67] Although the current method of disposing of nuclear waste from nuclear power plants in deep burials is generally considered safe, accidents during the transportation of nuclear waste can still result in the leakage of nuclear contaminants.^[68]

Large-scale nuclear accidents, like Chernobyl or Fukushima, release large quantities of radioactive material into nature, harming creatures and people.^[69][70] Solutions include enhanced regulatory and operational training, reducing radioactivity to surface organisms by deep burial or other treatment of radioactive contaminants at the accident site and creating permanent exclusion zones.^[71]

• List of commercial nuclear reactors
• List of nuclear power stations