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159-466: This covers nuclear power plants and all other nuclear facilities, the transportation of nuclear materials, and the use and storage of nuclear materials for medical, power, industry, and military uses. The nuclear power industry has improved the safety and performance of reactors , and has proposed new and safer reactor designs. However, a perfect safety cannot be guaranteed. Potential sources of problems include human errors and external events that have

318-576: A Level 2 event on the International Nuclear Event Scale during the 1999 Blayais Nuclear Power Plant flood , while flooding caused by the 2011 Tōhoku earthquake and tsunami lead to the Fukushima I nuclear accidents . The design of plants located in seismically active zones also requires the risk of earthquakes and tsunamis to be taken into account. Japan, India, China and the USA are among

477-403: A neutron hits the nucleus of a uranium-235 or plutonium atom, it can split the nucleus into two smaller nuclei, which is a nuclear fission reaction. The reaction releases energy and neutrons. The released neutrons can hit other uranium or plutonium nuclei, causing new fission reactions, which release more energy and more neutrons. This is called a chain reaction . In most commercial reactors,

636-447: A nuclear accident occurs, resulting from an unanticipated interaction of multiple failures in a complex system. TMI was an example of a normal accident because it was "unexpected, incomprehensible, uncontrollable and unavoidable". Perrow concluded that the failure at Three Mile Island was a consequence of the system's immense complexity. Such modern high-risk systems, he realized, were prone to failures however well they were managed. It

795-493: A nuclear renaissance , an increase in the construction of new reactors, due to concerns about carbon dioxide emissions . During this period, newer generation III reactors , such as the EPR began construction. Prospects of a nuclear renaissance were delayed by another nuclear accident. The 2011 Fukushima Daiichi nuclear accident was caused by the Tōhoku earthquake and tsunami , one of

954-507: A steam turbine connected to a generator that produces electricity . As of September 2023 , 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. Building a nuclear power plant often spans five to ten years, which can accrue significant financial costs, depending on how

1113-460: A condenser. The condenser is a heat exchanger which is connected to a secondary side such as a river or a cooling tower . The water is then pumped back into the steam generator and the cycle begins again. The water-steam cycle corresponds to the Rankine cycle . The nuclear reactor is the heart of the station. In its central part, the reactor's core produces heat due to nuclear fission. With this heat,

1272-442: A coolant is heated as it is pumped through the reactor and thereby removes the energy from the reactor. The heat from nuclear fission is used to raise steam, which runs through turbines , which in turn power the electrical generators. Nuclear reactors usually rely on uranium to fuel the chain reaction. Uranium is a very heavy metal that is abundant on Earth and is found in sea water as well as most rocks. Naturally occurring uranium

1431-402: A facility has been completely decommissioned it is released from regulatory control, and the licensee of the station no longer has responsibility for its nuclear safety. Generally speaking, nuclear stations were originally designed for a life of about 30 years. Newer stations are designed for a 40 to 60-year operating life. The Centurion Reactor is a future class of nuclear reactor that

1590-453: A greater impact than anticipated: the designers of reactors at Fukushima in Japan did not anticipate that a tsunami generated by an earthquake would disable the backup systems which were supposed to stabilize the reactor after the earthquake. Catastrophic scenarios involving terrorist attacks , war , insider sabotage , and cyberattacks are also conceivable. Nuclear weapon safety, as well as

1749-545: A high level of nuclear safety worldwide, to establish and maintain effective defences in nuclear installations against potential radiological hazards, and to prevent accidents having radiological consequences. The convention was drawn up in the aftermath of the Three Mile Island and Chernobyl accidents at a series of expert level meetings from 1992 to 1994, and was the result of considerable work by States, including their national regulatory and nuclear safety authorities, and

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1908-410: A low-level waste disposal site. In countries with nuclear power, radioactive wastes account for less than 1% of total industrial toxic wastes, much of which remains hazardous for long periods. Overall, nuclear power produces far less waste material by volume than fossil-fuel based power plants. Coal-burning plants, in particular, produce large amounts of toxic and mildly radioactive ash resulting from

2067-520: A nuclear power plant is currently being discussed. Such a terrorist attack could have catastrophic consequences. For example, the German government has confirmed that the nuclear power plant Biblis A would not be completely protected from an attack by a military aircraft. Following the terrorist attacks in Brussels in 2016, several nuclear power plants were partially evacuated. At the same time, it became known that

2226-404: A nuclear reactor heats the reactor coolant. The coolant may be water or gas, or even liquid metal, depending on the type of reactor. The reactor coolant then goes to a steam generator and heats water to produce steam. The pressurized steam is then usually fed to a multi-stage steam turbine . After the steam turbine has expanded and partially condensed the steam, the remaining vapor is condensed in

2385-479: A nuclear station is smaller than the fuel cost for operation of coal or gas plants. Since most of the cost of nuclear power plant is capital cost, there is almost no cost saving by running it at less than full capacity. Nuclear power plants are routinely used in load following mode on a large scale in France, although "it is generally accepted that this is not an ideal economic situation for nuclear stations". Unit A at

2544-506: 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. Where cheap gas is available and its future supply relatively secure, this also poses a major problem for nuclear projects. Analysis of the economics of nuclear power must take into account who bears

2703-444: 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; however, some exporting projects were canceled due to

2862-533: A reactor. Spent thorium fuel, although more difficult to handle than spent uranium fuel, may present somewhat lower proliferation risks. The nuclear industry also produces a large volume of low-level waste , with low radioactivity, in the form of contaminated items like clothing, hand tools, water purifier resins, and (upon decommissioning) the materials of which the reactor itself is built. Low-level waste can be stored on-site until radiation levels are low enough to be disposed of as ordinary waste, or it can be sent to

3021-1087: A shortage near the end of the century. A 2017 study by researchers from MIT and WHOI found that "at the current consumption rate, global conventional reserves of terrestrial uranium (approximately 7.6 million tonnes) could be depleted in a little over a century". Limited uranium-235 supply may inhibit substantial expansion with the current nuclear technology. While various ways to reduce dependence on such resources are being explored, new nuclear technologies are considered to not be available in time for climate change mitigation purposes or competition with alternatives of renewables in addition to being more expensive and require costly research and development. A study found it to be uncertain whether identified resources will be developed quickly enough to provide uninterrupted fuel supply to expanded nuclear facilities and various forms of mining may be challenged by ecological barriers, costs, and land requirements. Researchers also report considerable import dependence of nuclear energy. Unconventional uranium resources also exist. Uranium

3180-405: A significant effect on countries, such as France and Japan , which had relied more heavily on oil for electric generation to invest in nuclear power. France would construct 25 nuclear power plants over the next 15 years, and as of 2019, 71% of French electricity was generated by nuclear power, the highest percentage by any nation in the world. Some local opposition to nuclear power emerged in

3339-587: A significantly different evaluation of the economics of new nuclear power stations. 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. 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

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3498-413: 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,

3657-427: 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. The most serious accidents to date have been

3816-482: A three-year research study of offshore floating nuclear power generation. In October 2022, NuScale Power and Canadian company Prodigy announced a joint project to bring a North American small modular reactor based floating plant to market. 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

3975-425: A typical nuclear power station are often stored on site in dry cask storage vessels. Presently, waste is mainly stored at individual reactor sites and there are over 430 locations around the world where radioactive material continues to accumulate. Disposal of nuclear waste is often considered the most politically divisive aspect in the lifecycle of a nuclear power facility. The lack of movement of nuclear waste in

4134-580: 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,

4293-490: 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

4452-408: Is spent nuclear fuel , which is considered high-level waste . For Light Water Reactors (LWRs), spent fuel is typically composed of 95% uranium, 4% fission products , and about 1% transuranic actinides (mostly plutonium , neptunium and americium ). The fission products are responsible for the bulk of the short-term radioactivity, whereas the plutonium and other transuranics are responsible for

4611-721: Is 89%. Most new reactors under construction are generation III reactors in Asia. Proponents contend that nuclear power is a safe, sustainable energy source that reduces carbon emissions . This is because nuclear power generation causes one of the lowest levels of fatalities per unit of energy generated compared to other energy sources. Coal, petroleum, natural gas and hydroelectricity have each caused more fatalities per unit of energy due to air pollution and accidents . Nuclear power plants also emit no greenhouse gases and result in less life-cycle carbon emissions than common "renewables". The radiological hazards associated with nuclear power are

4770-482: Is a fairly common element in the Earth's crust: it is approximately as common as tin or germanium , and is about 40 times more common than silver . Uranium is present in trace concentrations in most rocks, dirt, and ocean water, but is generally economically extracted only where it is present in relatively high concentrations. Uranium mining can be underground, open-pit , or in-situ leach mining. An increasing number of

4929-626: Is a requirement and necessary for chemical facilities, operating nuclear reactors and many other utility facilities. In 2003, the United States Nuclear Regulatory Commission (NRC) developed mandates regarding enhanced security at nuclear power plants. Primary among them were changes to the security perimeter and the screening of employees, vendors, and visitors as they accessed the site. Many facilities recognize their vulnerabilities, and licensed security-contracting firms have arisen. The Fukushima nuclear disaster illustrated

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5088-454: Is about 1/3 of solar and 1/45 of natural gas and 1/75 of coal . 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. Nuclear power Nuclear power is the use of nuclear reactions to produce electricity . Nuclear power can be obtained from nuclear fission , nuclear decay and nuclear fusion reactions. Presently,

5247-461: Is also produced during plant decommissioning. There are two broad categories of nuclear waste: low-level waste and high-level waste. The first has low radioactivity and includes contaminated items such as clothing, which poses limited threat. High-level waste is mainly the spent fuel from nuclear reactors, which is very radioactive and must be cooled and then safely disposed of or reprocessed. The most important waste stream from nuclear power reactors

5406-489: Is also safer in terms of nuclear proliferation potential. Reprocessing has the potential to recover up to 95% of the uranium and plutonium fuel in spent nuclear fuel, as well as reduce long-term radioactivity within the remaining waste. However, reprocessing has been politically controversial because of the potential for nuclear proliferation and varied perceptions of increasing the vulnerability to nuclear terrorism . Reprocessing also leads to higher fuel cost compared to

5565-520: Is anticipated to resume similar levels of nuclear energy utilization. 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

5724-503: Is being designed to last 100 years. One of the major limiting wear factors is the deterioration of the reactor's pressure vessel under the action of neutron bombardment, however in 2018 Rosatom announced it had developed a thermal annealing technique for reactor pressure vessels which ameliorates radiation damage and extends service life by between 15 and 30 years. Nuclear stations are used primarily for base load because of economic considerations. The fuel cost of operations for

5883-490: Is considered the worst nuclear disaster in history both in total casualties, with 56 direct deaths, and financially, with the cleanup and the cost estimated at 18   billion   Rbls (US$ 68   billion in 2019, adjusted for inflation). The international organization to promote safety awareness and the professional development of operators in nuclear facilities, the World Association of Nuclear Operators (WANO),

6042-410: Is contained within sixteen casks. It is estimated that to produce a lifetime supply of energy for a person at a western standard of living (approximately 3   GWh ) would require on the order of the volume of a soda can of low enriched uranium , resulting in a similar volume of spent fuel generated. Following interim storage in a spent fuel pool , the bundles of used fuel rod assemblies of

6201-498: Is currently done in France, the United Kingdom, Russia, Japan, and India. In the United States, spent nuclear fuel is currently not reprocessed. The La Hague reprocessing facility in France has operated commercially since 1976 and is responsible for half the world's reprocessing as of 2010. It produces MOX fuel from spent fuel derived from several countries. More than 32,000 tonnes of spent fuel had been reprocessed as of 2015, with

6360-431: Is found in two different isotopes : uranium-238 (U-238), accounting for 99.3% and uranium-235 (U-235) accounting for about 0.7%. U-238 has 146 neutrons and U-235 has 143 neutrons. Different isotopes have different behaviors. For instance, U-235 is fissile which means that it is easily split and gives off a lot of energy making it ideal for nuclear energy. On the other hand, U-238 does not have that property despite it being

6519-441: Is impossible for a commercial nuclear reactor to explode like a nuclear bomb since the fuel is never sufficiently enriched for this to occur. Nuclear reactors can fail in a variety of ways. Should the instability of the nuclear material generate unexpected behavior, it may result in an uncontrolled power excursion. Normally, the cooling system in a reactor is designed to be able to handle the excess heat this causes; however, should

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6678-405: Is in the commissioning phase, with plans to build more. Another alternative to fast-neutron breeders are thermal-neutron breeder reactors that use uranium-233 bred from thorium as fission fuel in the thorium fuel cycle . Thorium is about 3.5 times more common than uranium in the Earth's crust, and has different geographic characteristics. India's three-stage nuclear power programme features

6837-424: Is more expensive than producing new fuel from mined uranium . 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. The first nuclear power plant was built in the 1950s. The global installed nuclear capacity grew to 100   GW in the late 1970s, and then expanded during

6996-521: Is much less radioactive than spent nuclear fuel by weight, coal ash is produced in much higher quantities per unit of energy generated. It is also released directly into the environment as fly ash , whereas nuclear plants use shielding to protect the environment from radioactive materials. Nuclear waste volume is small compared to the energy produced. For example, at Yankee Rowe Nuclear Power Station , which generated 44 billion kilowatt hours of electricity when in service, its complete spent fuel inventory

7155-478: Is naturally present in seawater at a concentration of about 3 micrograms per liter, with 4.4 billion tons of uranium considered present in seawater at any time. In 2014 it was suggested that it would be economically competitive to produce nuclear fuel from seawater if the process was implemented at large scale. Like fossil fuels, over geological timescales, uranium extracted on an industrial scale from seawater would be replenished by both river erosion of rocks and

7314-617: Is the reactor-grade plutonium (RGPu) that is extracted from spent fuel. It is mixed with uranium oxide and fabricated into mixed-oxide or MOX fuel . Because thermal LWRs remain the most common reactor worldwide, this type of recycling is the most common. It is considered to increase the sustainability of the nuclear fuel cycle, reduce the attractiveness of spent fuel to theft, and lower the volume of high level nuclear waste. Spent MOX fuel cannot generally be recycled for use in thermal-neutron reactors. This issue does not affect fast-neutron reactors , which are therefore preferred in order to achieve

7473-605: Is the main body dealing with ionizing and non-ionizing radiation and publishes material regarding radiation protection. Other agencies include: Nuclear power plants are some of the most sophisticated and complex energy systems ever designed. Any complex system, no matter how well it is designed and engineered, cannot be deemed failure-proof. Veteran journalist and author Stephanie Cooke has argued: The reactors themselves were enormously complex machines with an incalculable number of things that could go wrong. When that happened at Three Mile Island in 1979, another fault line in

7632-429: Is the only nuclear facility that does not use a natural body of water for cooling, instead it uses treated sewage from the greater Phoenix metropolitan area. The water coming from the cooling body of water is either pumped back to the water source at a warmer temperature or returns to a cooling tower where it either cools for more uses or evaporates into water vapor that rises out the top of the tower. The water level in

7791-458: Is then converted into a compact ore concentrate form, known as yellowcake (U 3 O 8 ), to facilitate transport. Fission reactors generally need uranium-235 , a fissile isotope of uranium . The concentration of uranium-235 in natural uranium is low (about 0.7%). Some reactors can use this natural uranium as fuel, depending on their neutron economy . These reactors generally have graphite or heavy water moderators. For light water reactors,

7950-505: The 2011 Japanese nuclear accidents have revealed that the nuclear industry lacks sufficient oversight, leading to renewed calls to redefine the mandate of the IAEA so that it can better police nuclear power plants worldwide. The IAEA Convention on Nuclear Safety was adopted in Vienna on 17 June 1994 and entered into force on 24 October 1996. The objectives of the convention are to achieve and maintain

8109-486: The BWR , the steam is directed into the suppression chamber and condenses there. The chambers on a heat exchanger are connected to the intermediate cooling circuit. The main condenser is a large cross-flow shell and tube heat exchanger that takes wet vapor, a mixture of liquid water and steam at saturation conditions, from the turbine-generator exhaust and condenses it back into sub-cooled liquid water so it can be pumped back to

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8268-524: The Onkalo spent nuclear fuel repository of the Olkiluoto Nuclear Power Plant was under construction as of 2015. Most thermal-neutron reactors run on a once-through nuclear fuel cycle , mainly due to the low price of fresh uranium. However, many reactors are also fueled with recycled fissionable materials that remain in spent nuclear fuel. The most common fissionable material that is recycled

8427-491: The Russian invasion of Ukraine . 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. Nuclear decommissioning is the dismantling of a nuclear power station and decontamination of the site to a state no longer requiring protection from radiation for the general public. The main difference from

8586-523: The September 11 attacks in the U.S. However, it was in 1972 when three hijackers took control of a domestic passenger flight along the east coast of the U.S. and threatened to crash the plane into a U.S. nuclear weapons plant in Oak Ridge, Tennessee. The plane got as close as 8,000 feet above the site before the hijackers’ demands were met. The most important barrier against the release of radioactivity in

8745-769: The Soviet Union . 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 . 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. The conversion to electrical energy takes place indirectly, as in conventional thermal power stations. The fission in

8904-656: 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

9063-439: The integral fast reactor and molten salt reactors , can use as fuel the plutonium and other actinides in spent fuel from light water reactors, thanks to their fast fission spectrum. This offers a potentially more attractive alternative to deep geological disposal. The thorium fuel cycle results in similar fission products, though creates a much smaller proportion of transuranic elements from neutron capture events within

9222-422: The thermal energy released from nuclear fission . A fission nuclear power plant is generally composed of: a nuclear reactor , in which the nuclear reactions generating heat take place; a cooling system, which removes the heat from inside the reactor; a steam turbine , which transforms the heat into mechanical energy ; an electric generator , which transforms the mechanical energy into electrical energy. When

9381-424: The 1970s and 1980s, when it "reached an intensity unprecedented in the history of technology controversies," in some countries. 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. Proponents advance the notion that nuclear power produces virtually no air pollution, in contrast to

9540-485: 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. An interdisciplinary team from MIT has estimated that given

9699-575: The 1980s, reaching 300   GW by 1990. The 1979 Three Mile Island accident in the United States and the 1986 Chernobyl disaster in the Soviet Union resulted in increased regulation and public opposition to nuclear power plants. These factors, along with high cost of construction, resulted in the global installed capacity only increasing to 392   GW by 2023. These plants supplied 2,602 terawatt hours (TWh) of electricity in 2023, equivalent to about 9% of global electricity generation , and were

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9858-757: The 2 billion year old natural nuclear fission reactors in Oklo , Gabon is cited as "a source of essential information today." Experts suggest that centralized underground repositories which are well-managed, guarded, and monitored, would be a vast improvement. There is an "international consensus on the advisability of storing nuclear waste in deep geological repositories ". With the advent of new technologies, other methods including horizontal drillhole disposal into geologically inactive areas have been proposed. There are no commercial scale purpose built underground high-level waste repositories in operation. However, in Finland

10017-456: The 2011 disaster. Kishida is also pushing for research and construction of new safer nuclear plants to safeguard Japanese consumers from the fluctuating price of the fossil fuel market and reduce Japan's greenhouse gas emissions. Kishida intends to have Japan become a significant exporter of nuclear energy and technology to developing countries around the world. By 2015, the IAEA's outlook for nuclear energy had become more promising, recognizing

10176-508: The Brussels supplementary convention, and the Vienna Convention on Civil Liability for Nuclear Damage . 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. The nuclear power debate about the deployment and use of nuclear fission reactors to generate electricity from nuclear fuel for civilian purposes peaked during

10335-672: The IAEA, says Najmedin Meshkati of University of Southern California, writing in 2011: "It recommends safety standards, but member states are not required to comply; it promotes nuclear energy, but it also monitors nuclear use; it is the sole global organization overseeing the nuclear energy industry, yet it is also weighed down by checking compliance with the Nuclear Non-Proliferation Treaty (NPT)". Many nations utilizing nuclear power have specialist institutions overseeing and regulating nuclear safety. Civilian nuclear safety in

10494-627: The International Atomic Energy Agency, which serves as the Secretariat for the convention. The obligations of the Contracting Parties are based to a large extent on the application of the safety principles for nuclear installations contained in the IAEA document Safety Fundamentals ‘The Safety of Nuclear Installations’ (IAEA Safety Series No. 110 published 1993). These obligations cover the legislative and regulatory framework,

10653-549: The Japanese government shared the blame for the Fukushima disaster, saying that officials had been blinded by an image of the country's technological infallibility and were "all too steeped in a safety myth." Japan has been accused by authors such as journalist Yoichi Funabashi of having an "aversion to facing the potential threat of nuclear emergencies." According to him, a national program to develop robots for use in nuclear emergencies

10812-604: The PWR being the reactor of choice also for power generation, thus having a lasting impact on the civilian electricity market in the years to come. On June 27, 1954, the Obninsk Nuclear Power Plant in the USSR became the world's first nuclear power plant to generate electricity for a power grid , producing around 5 megawatts of electric power. The world's first commercial nuclear power station, Calder Hall at Windscale, England

10971-503: The U.S. is regulated by the Nuclear Regulatory Commission (NRC). However, critics of the nuclear industry complain that the regulatory bodies are too intertwined with the industries themselves to be effective. The book The Doomsday Machine for example, offers a series of examples of national regulators, as they put it 'not regulating, just waving' (a pun on waiving ) to argue that, in Japan, for example, "regulators and

11130-424: The U.S. Electric Power Research Institute that tested the robustness of both reactor and waste fuel storage and found that they should be able to sustain a terrorist attack comparable to the September 11 terrorist attacks in the U.S. Spent fuel is usually housed inside the plant's "protected zone" or a spent nuclear fuel shipping cask ; stealing it for use in a " dirty bomb " would be extremely difficult. Exposure to

11289-768: The U.S. government for research, weapons production, and those powering naval vessels is not governed by the NRC. In the UK nuclear safety is regulated by the Office for Nuclear Regulation (ONR) and the Defence Nuclear Safety Regulator (DNSR). The Australian Radiation Protection and Nuclear Safety Agency ( ARPANSA ) is the Federal Government body that monitors and identifies solar radiation and nuclear radiation risks in Australia. It

11448-581: The United States in the early 1960s. In the late 1960s, some members of the scientific community began to express pointed concerns. These anti-nuclear concerns related to nuclear accidents , nuclear proliferation , nuclear terrorism and radioactive waste disposal . In the early 1970s, there were large protests about a proposed nuclear power plant in Wyhl , Germany. The project was cancelled in 1975. The anti-nuclear success at Wyhl inspired opposition to nuclear power in other parts of Europe and North America. By

11607-401: The United States, over 120 Light Water Reactor proposals were ultimately cancelled and the construction of new reactors ground to a halt. The 1979 accident at Three Mile Island with no fatalities, played a major part in the reduction in the number of new plant constructions in many countries. During the 1980s one new nuclear reactor started up every 17 days on average. By the end of

11766-540: The above objective. Reasonably practicable or achievable safety improvements are to be implemented in a timely manner. 3. National requirements and regulations for addressing this objective throughout the lifetime of nuclear power plants are to take into account the relevant IAEA Safety Standards and, as appropriate, other good practices as identified inter alia in the Review Meetings of the CNS. There are several problems with

11925-632: The actinides (the most active and dangerous components) in the present inventory of nuclear waste, while also producing power and creating additional quantities of fuel for more reactors via the breeding process. As of 2017, there are two breeders producing commercial power, BN-600 reactor and the BN-800 reactor , both in Russia. The Phénix breeder reactor in France was powered down in 2009 after 36 years of operation. Both China and India are building breeder reactors. The Indian 500 MWe Prototype Fast Breeder Reactor

12084-479: The air, water and soil. NRC says, "nuclear power plants sometimes release radioactive gases and liquids into the environment under controlled, monitored conditions to ensure that they pose no danger to the public or the environment", and "routine emissions during normal operation of a nuclear power plant are never lethal". According to the United Nations ( UNSCEAR ), regular nuclear power plant operation including

12243-584: The building of larger single-purpose production reactors for the production of weapons-grade plutonium for use in the first nuclear weapons. The United States tested the first nuclear weapon in July 1945, the Trinity test , and the atomic bombings of Hiroshima and Nagasaki happened one month later. Despite the military nature of the first nuclear devices, there was strong optimism in the 1940s and 1950s that nuclear power could provide cheap and endless energy. Electricity

12402-702: The bulk of the long-term radioactivity. High-level waste (HLW) must be stored isolated from the biosphere with sufficient shielding so as to limit radiation exposure. After being removed from the reactors, used fuel bundles are stored for six to ten years in spent fuel pools , which provide cooling and shielding against radiation. After that, the fuel is cool enough that it can be safely transferred to dry cask storage . The radioactivity decreases exponentially with time, such that it will have decreased by 99.5% after 100 years. The more intensely radioactive short-lived fission products (SLFPs) decay into stable elements in approximately 300 years, and after about 100,000 years,

12561-552: 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. Opponents say that nuclear power poses many threats to people and

12720-415: The concentration of naturally occurring radioactive materials in coal. A 2008 report from Oak Ridge National Laboratory concluded that coal power actually results in more radioactivity being released into the environment than nuclear power operation, and that the population effective dose equivalent from radiation from coal plants is 100 times that from the operation of nuclear plants. Although coal ash

12879-403: The cooling pumps caused the Fukushima meltdown. Nuclear power plant A nuclear power plant ( NPP ), 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

13038-485: The cooling systems, as happened in Fukushima I , can cause serious accidents. Nuclear safety rules in the United States "do not adequately weigh the risk of a single event that would knock out electricity from the grid and from emergency generators, as a quake and tsunami recently did in Japan", Nuclear Regulatory Commission officials said in June 2011. Nuclear reactors become preferred targets during military conflict and, over

13197-485: The costs of fuel extraction, processing, use and spent fuel storage internalized costs. 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

13356-419: The countries to have plants in earthquake-prone regions. Damage caused to Japan's Kashiwazaki-Kariwa Nuclear Power Plant during the 2007 Chūetsu offshore earthquake underlined concerns expressed by experts in Japan prior to the Fukushima accidents, who have warned of a genpatsu-shinsai (domino-effect nuclear power plant earthquake disaster). Safeguarding critical infrastructure like nuclear power plants

13515-716: The cusp of World War II , in order to develop a nuclear weapon . In the United States, these research efforts led to the creation of the first man-made nuclear reactor, the Chicago Pile-1 under the Stagg Field stadium at the University of Chicago , which achieved criticality on December 2, 1942. The reactor's development was part of the Manhattan Project , the Allied effort to create atomic bombs during World War II. It led to

13674-407: The dangers of building multiple nuclear reactor units close to one another. Because of the closeness of the reactors, Plant Director Masao Yoshida "was put in the position of trying to cope simultaneously with core meltdowns at three reactors and exposed fuel pools at three units". The three primary objectives of nuclear safety systems as defined by the Nuclear Regulatory Commission are to shut down

13833-409: The decade, global installed nuclear capacity reached 300   GW. Since the late 1980s, new capacity additions slowed significantly, with the installed nuclear capacity reaching 366   GW in 2005. The 1986 Chernobyl disaster in the USSR , involving an RBMK reactor, altered the development of nuclear power and led to a greater focus on meeting international safety and regulatory standards. It

13992-419: The design needs to take the risk of flooding and tsunamis into account. The World Energy Council (WEC) argues disaster risks are changing and increasing the likelihood of disasters such as earthquakes , cyclones , hurricanes , typhoons , flooding . High temperatures, low precipitation levels and severe droughts may lead to fresh water shortages. Failure to calculate the risk of flooding correctly lead to

14151-424: The destruction of a turbine in operation from flying towards the reactor. In the case of a pressurized water reactor, the steam turbine is separated from the nuclear system. To detect a leak in the steam generator and thus the passage of radioactive water at an early stage, an activity meter is mounted to track the outlet steam of the steam generator. In contrast, boiling water reactors pass radioactive water through

14310-416: The disaster, Japan shut down all of its nuclear power reactors, some of them permanently, and in 2015 began a gradual process to restart the remaining 40 reactors, following safety checks and based on revised criteria for operations and public approval. In 2022, the Japanese government, under the leadership of Prime Minister Fumio Kishida , declared that 10 more nuclear power plants were to be reopened since

14469-458: The dismantling of other power stations is the presence of radioactive material that requires special precautions to remove and safely relocate to a waste repository. Decommissioning involves many administrative and technical actions. It includes all clean-up of radioactivity and progressive demolition of the station. Once a facility is decommissioned, there should no longer be any danger of a radioactive accident or to any persons visiting it. After

14628-534: 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. 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. On 1 August 2020,

14787-402: The environment and raising the possibility of nuclear proliferation." 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

14946-775: The environment, 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 . 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 . Critics do not believe that these risks can be reduced through new technology , despite rapid advancements in containment procedures and storage methods. Opponents argue that when all

15105-411: The environment. In addition, many reactors are equipped with a dome of concrete to protect the reactor against both internal casualties and external impacts. The purpose of the steam turbine is to convert the heat contained in steam into mechanical energy. The engine house with the steam turbine is usually structurally separated from the main reactor building. It is aligned so as to prevent debris from

15264-512: The event of an aircraft strike on a nuclear power plant is the containment building and its missile shield. Former NRC Chairman Dale Klein has said "Nuclear power plants are inherently robust structures that our studies show provide adequate protection in a hypothetical attack by an airplane. The NRC has also taken actions that require nuclear power plant operators to be able to manage large fires or explosions—no matter what has caused them." In addition, supporters point to large studies carried out by

15423-513: The expected growth of nuclear power from 2005 to 2055, at least four serious nuclear accidents would be expected in that period. The MIT study does not take into account improvements in safety since 1970. 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 ,

15582-452: The full energy potential of the original uranium. The main constituent of spent fuel from LWRs is slightly enriched uranium . This can be recycled into reprocessed uranium (RepU), which can be used in a fast reactor, used directly as fuel in CANDU reactors, or re-enriched for another cycle through an LWR. Re-enriching of reprocessed uranium is common in France and Russia. Reprocessed uranium

15741-515: The heart of France's drive for carbon neutrality by 2050. Meanwhile, in the United States, the Department of Energy , in collaboration with commercial entities, TerraPower and X-energy , is planning on building two different advanced nuclear reactors by 2027, with further plans for nuclear implementation in its long term green energy and energy security goals. Nuclear power plants are thermal power stations that generate electricity by harnessing

15900-570: The highest output mines are remote underground operations, such as McArthur River uranium mine , in Canada, which by itself accounts for 13% of global production. As of 2011 the world's known resources of uranium, economically recoverable at the arbitrary price ceiling of US$ 130/kg, were enough to last for between 70 and 100 years. In 2007, the OECD estimated 670 years of economically recoverable uranium in total conventional resources and phosphate ores assuming

16059-406: The hot coolant is used as a heat source for a boiler, and the pressurized steam from that drives one or more steam turbine driven electrical generators . In the event of an emergency, safety valves can be used to prevent pipes from bursting or the reactor from exploding. The valves are designed so that they can derive all of the supplied flow rates with little increase in pressure. In the case of

16218-425: The importance of low-carbon generation for mitigating climate change . As of 2015 , the global trend was for new nuclear power stations coming online to be balanced by the number of old plants being retired. In 2016, the U.S. Energy Information Administration projected for its "base case" that world nuclear power generation would increase from 2,344 terawatt hours (TWh) in 2012 to 4,500   TWh in 2040. Most of

16377-517: The initial investments are financed. 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. Nuclear power plants have a carbon footprint comparable to that of renewable energy such as solar farms and wind farms , and much lower than fossil fuels such as natural gas and coal . Nuclear power plants are among

16536-564: The intense radiation would almost certainly quickly incapacitate or kill anyone who attempts to do so. Nuclear power plants are considered to be targets for terrorist attacks. Even during the construction of the first nuclear power plants, this issue has been advised by security bodies. Concrete threats of attack against nuclear power plants by terrorists or criminals are documented from several states. While older nuclear power plants were built without special protection against air accidents in Germany,

16695-569: The largest earthquakes ever recorded. The Fukushima Daiichi Nuclear Power Plant suffered three core meltdowns due to failure of the emergency cooling system for lack of electricity supply. This resulted in the most serious nuclear accident since the Chernobyl disaster. The accident prompted a re-examination of nuclear safety and nuclear energy policy in many countries. Germany approved plans to close all its reactors by 2022, and many other countries reviewed their nuclear power programs. Following

16854-547: The late 1970s. During the 1970s and 1980s rising economic costs (related to extended construction times largely due to regulatory changes and pressure-group litigation) and falling fossil fuel prices made nuclear power plants then under construction less attractive. In the 1980s in the U.S. and 1990s in Europe, the flat electric grid growth and electricity liberalization also made the addition of large new baseload energy generators economically unattractive. The 1973 oil crisis had

17013-416: The later nuclear power plants built with a massive concrete buildings are partially protected against air accidents. They are designed against the impact of combat aircraft at a speed of about 800 km / h. It was assumed as a basis of assessment of the impact of an aircraft of type Phantom II with a mass of 20 tonnes and speed of 215 m / s. The danger arising from a terrorist caused large aircraft crash on

17172-516: The life of nuclear fuel to a few years. In some countries, such as the United States, spent fuel is classified in its entirety as a nuclear waste. In other countries, such as France, it is largely reprocessed to produce a partially recycled fuel, known as mixed oxide fuel or MOX . For spent fuel that does not undergo reprocessing, the most concerning isotopes are the medium-lived transuranic elements , which are led by reactor-grade plutonium (half-life 24,000 years). Some proposed reactor designs, such as

17331-719: The majority from France, 17% from Germany, and 9% from Japan. Breeding is the process of converting non-fissile material into fissile material that can be used as nuclear fuel. The non-fissile material that can be used for this process is called fertile material , and constitute the vast majority of current nuclear waste. This breeding process occurs naturally in breeder reactors . As opposed to light water thermal-neutron reactors, which use uranium-235 (0.7% of all natural uranium), fast-neutron breeder reactors use uranium-238 (99.3% of all natural uranium) or thorium. A number of fuel cycles and breeder reactor combinations are considered to be sustainable or renewable sources of energy. In 2006 it

17490-488: The mid-1970s anti-nuclear activism gained a wider appeal and influence, and nuclear power began to become an issue of major public protest. In some countries, the nuclear power conflict "reached an intensity unprecedented in the history of technology controversies". The increased public hostility to nuclear power led to a longer license procurement process, more regulations and increased requirements for safety equipment, which made new construction much more expensive. In

17649-437: The most common type of reactor, this concentration is too low, and it must be increased by a process called uranium enrichment . In civilian light water reactors, uranium is typically enriched to 3.5–5% uranium-235. The uranium is then generally converted into uranium oxide (UO 2 ), a ceramic, that is then compressively sintered into fuel pellets, a stack of which forms fuel rods of the proper composition and geometry for

17808-418: The most hazardous substances in nuclear waste), there is an estimated 160,000 years worth of uranium in total conventional resources and phosphate ore at the price of 60–100 US$ /kg. However, reprocessing is expensive, possibly dangerous and can be used to manufacture nuclear weapons. One analysis found that uranium prices could increase by two orders of magnitude between 2035 and 2100 and that there could be

17967-428: The natural process of uranium dissolved from the surface area of the ocean floor, both of which maintain the solubility equilibria of seawater concentration at a stable level. Some commentators have argued that this strengthens the case for nuclear power to be considered a renewable energy . The normal operation of nuclear power plants and facilities produce radioactive waste , or nuclear waste. This type of waste

18126-432: The near future. 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,

18285-430: The need to limit the biological uptake of committed dose (ingestion or inhalation of radioactive materials), and external radiation dose due to radioactive contamination . Nuclear safety therefore covers at minimum: Internationally the International Atomic Energy Agency "works with its Member States and multiple partners worldwide to promote safe, secure and peaceful nuclear technologies." Some scientists say that

18444-586: The need to spend more on redundant back up safety equipment. According to the World Nuclear Association , as of March 2020: The Russian state nuclear company Rosatom is the largest player in international nuclear power market, building nuclear plants around the world. Whereas Russian oil and gas were subject to international sanctions after the Russian full-scale invasion of Ukraine in February 2022, Rosatom

18603-473: The now decommissioned German Biblis Nuclear Power Plant was designed to modulate its output 15% per minute between 40% and 100% of its nominal power. Russia has led in the practical development of floating nuclear power stations , which can be transported to the desired location and occasionally relocated or moved for easier decommissioning. In 2022, the United States Department of Energy funded

18762-420: The nuclear fuel cycle amounts to 0.0002 millisieverts (mSv) annually in average public radiation exposure; the legacy of the Chernobyl disaster is 0.002 mSv/a as a global average as of a 2008 report; and natural radiation exposure averages 2.4 mSv annually although frequently varying depending on an individual's location from 1 to 13 mSv. In March 2012, Prime Minister Yoshihiko Noda said that

18921-436: The nuclear world was exposed. One malfunction led to another, and then to a series of others, until the core of the reactor itself began to melt, and even the world's most highly trained nuclear engineers did not know how to respond. The accident revealed serious deficiencies in a system that was meant to protect public health and safety. The 1979 Three Mile Island accident inspired Perrow's book Normal Accidents , where

19080-543: The objective of preventing accidents in the commissioning and operation and, should an accident occur, mitigating possible releases of radionuclides causing long-term off site contamination and avoiding early radioactive releases or radioactive releases large enough to require long-term protective measures and actions. 2. Comprehensive and systematic safety assessments are to be carried out periodically and regularly for existing installations throughout their lifetime in order to identify safety improvements that are oriented to meet

19239-416: The once-through fuel cycle. While reprocessing reduces the volume of high-level waste, it does not reduce the fission products that are the primary causes of residual heat generation and radioactivity for the first few centuries outside the reactor. Thus, reprocessed waste still requires an almost identical treatment for the initial first few hundred years. Reprocessing of civilian fuel from power reactors

19398-469: The particular reactor. After some time in the reactor, the fuel will have reduced fissile material and increased fission products, until its use becomes impractical. At this point, the spent fuel will be moved to a spent fuel pool which provides cooling for the thermal heat and shielding for ionizing radiation. After several months or years, the spent fuel is radioactively and thermally cool enough to be moved to dry storage casks or reprocessed. Uranium

19557-405: The past three decades, have been repeatedly attacked during military air strikes, occupations, invasions and campaigns: In the U.S., plants are surrounded by a double row of tall fences which are electronically monitored. The plant grounds are patrolled by a sizeable force of armed guards. In Canada, all reactors have an "on-site armed response force" that includes light-armored vehicles that patrol

19716-431: The plants daily. The NRC's "Design Basis Threat" criterion for plants is a secret, and so what size of attacking force the plants are able to protect against is unknown. However, to scram (make an emergency shutdown) a plant takes fewer than 5 seconds while unimpeded restart takes hours, severely hampering a terrorist force in a goal to release radioactivity. Attack from the air is an issue that has been highlighted since

19875-497: The predicted increase was expected to be in Asia. As of 2018, there were over 150 nuclear reactors planned including 50 under construction. In January 2019, China had 45 reactors in operation, 13 under construction, and planned to build 43 more, which would make it the world's largest generator of nuclear electricity. As of 2021, 17 reactors were reported to be under construction. China built significantly fewer reactors than originally planned. Its share of electricity from nuclear power

20034-403: The primary motivations of the anti-nuclear movement , which contends that nuclear power poses many threats to people and the environment, citing the potential for accidents like the Fukushima nuclear disaster in Japan in 2011, and is too expensive/slow to deploy when compared to alternative sustainable energy sources. Nuclear fission was discovered in 1938 after over four decades of work on

20193-622: The private sector. The first organization to develop practical nuclear power was the U.S. Navy , with the S1W reactor for the purpose of propelling submarines and aircraft carriers . The first nuclear-powered submarine, USS  Nautilus , was put to sea in January 1954. The S1W reactor was a pressurized water reactor . This design was chosen because it was simpler, more compact, and easier to operate compared to alternative designs, thus more suitable to be used in submarines. This decision would result in

20352-474: 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 stable repository plans, therefore from

20511-462: The reaction rate is contained by control rods that absorb excess neutrons. The controllability of nuclear reactors depends on the fact that a small fraction of neutrons resulting from fission are delayed . The time delay between the fission and the release of the neutrons slows changes in reaction rates and gives time for moving the control rods to adjust the reaction rate. The life cycle of nuclear fuel starts with uranium mining . The uranium ore

20670-446: The reactor also experience a loss-of-coolant accident , then the fuel may melt or cause the vessel in which it is contained to overheat and melt. This event is called a nuclear meltdown . After shutting down, for some time the reactor still needs external energy to power its cooling systems. Normally this energy is provided by the power grid to which that plant is connected, or by emergency diesel generators. Failure to provide power for

20829-427: The reactor by the condensate and feedwater pumps. In the main condenser, the wet vapor turbine exhaust come into contact with thousands of tubes that have much colder water flowing through them on the other side. The cooling water typically come from a natural body of water such as a river or lake. Palo Verde Nuclear Generating Station , located in the desert about 97 kilometres (60 mi) west of Phoenix, Arizona,

20988-474: The reactor, maintain it in a shutdown condition, and prevent the release of radioactive material during events and accidents. These objectives are accomplished using a variety of equipment, which is part of different systems, of which each performs specific functions. During everyday routine operations, emissions of radioactive materials from nuclear plants are released to the outside of the plants although they are quite slight amounts. The daily emissions go into

21147-469: The regulated have long been friends, working together to offset the doubts of a public brought up on the horror of the nuclear bombs". Other examples offered include: The book argues that nuclear safety is compromised by the suspicion that, as Eisaku Sato, formerly a governor of Fukushima province (with its infamous nuclear reactor complex), has put it of the regulators: “They're all birds of a feather”. The safety of nuclear plants and materials controlled by

21306-545: The regulatory body, and technical safety obligations related to, for instance, siting, design, construction, operation, the availability of adequate financial and human resources, the assessment and verification of safety, quality assurance and emergency preparedness. The convention was amended in 2014 by the Vienna Declaration on Nuclear Safety. This resulted in the following principles: 1. New nuclear power plants are to be designed, sited, and constructed, consistent with

21465-637: The restart of another ten reactors. Prime Minister Fumio Kishida in July 2022 announced that the country should consider building advanced reactors and extending operating licences beyond 60 years. As of 2022, with world oil and gas prices on the rise, while Germany is restarting its coal plants to deal with loss of Russian gas that it needs to supplement its Energiewende , many other countries have announced ambitious plans to reinvigorate ageing nuclear generating capacity with new investments. French President Emmanuel Macron announced his intention to build six new reactors in coming decades, placing nuclear at

21624-540: 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. 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

21783-579: The safe disposal of its last radioactive waste, may be 100 to 150 years. There are concerns that a combination of human and mechanical error at a nuclear facility could result in significant harm to people and the environment: Operating nuclear reactors contain large amounts of radioactive fission products which, if dispersed, can pose a direct radiation hazard, contaminate soil and vegetation, and be ingested by humans and animals. Human exposure at high enough levels can cause both short-term illness and death and longer-term death by cancer and other diseases. It

21942-563: The safest modes of electricity generation, comparable to solar and wind power plants. 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. 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

22101-505: The safety of military research involving nuclear materials, is generally handled by agencies different from those that oversee civilian safety, for various reasons, including secrecy. There are ongoing concerns about terrorist groups acquiring nuclear bomb-making material. As of 2011, nuclear safety considerations occur in a number of situations, including: With the exception of thermonuclear weapons and experimental fusion research , all safety issues specific to nuclear power stems from

22260-407: The same element. Different isotopes also have different half-lives . U-238 has a longer half-life than U-235, so it takes longer to decay over time. This also means that U-238 is less radioactive than U-235. Since nuclear fission creates radioactivity, the reactor core is surrounded by a protective shield. This containment absorbs radiation and prevents radioactive material from being released into

22419-450: The science of radioactivity and the elaboration of new nuclear physics that described the components of atoms . Soon after the discovery of the fission process, it was realized that a fissioning nucleus can induce further nucleus fissions, thus inducing a self-sustaining chain reaction. Once this was experimentally confirmed in 1939, scientists in many countries petitioned their governments for support for nuclear fission research, just on

22578-512: The second-largest low-carbon power source after hydroelectricity . As of November 2024, there are 415 civilian fission reactors in the world , with overall capacity of 374   GW, 66 under construction and 87 planned, with a combined capacity of 72   GW and 84   GW, respectively. The United States has the largest fleet of nuclear reactors, generating almost 800   TWh of low-carbon electricity per year with an average capacity factor of 92%. The average global capacity factor

22737-426: The spent fuel becomes less radioactive than natural uranium ore. Commonly suggested methods to isolate LLFP waste from the biosphere include separation and transmutation , synroc treatments, or deep geological storage. Thermal-neutron reactors , which presently constitute the majority of the world fleet, cannot burn up the reactor grade plutonium that is generated during the reactor operation. This limits

22896-693: The steam generator and the nuclear reactor is controlled using the feedwater system. The feedwater pump has the task of taking the water from the condensate system, increasing the pressure and forcing it into either the steam generators—in the case of a pressurized water reactor — or directly into the reactor, for boiling water reactors . Continuous power supply to the plant is critical to ensure safe operation. Most nuclear stations require at least two distinct sources of offsite power for redundancy. These are usually provided by multiple transformers that are sufficiently separated and can receive power from multiple transmission lines. In addition, in some nuclear stations,

23055-487: The steam turbine, so the turbine is kept as part of the radiologically controlled area of the nuclear power station. The electric generator converts mechanical power supplied by the turbine into electrical power. Low-pole AC synchronous generators of high rated power are used. A cooling system removes heat from the reactor core and transports it to another area of the station, where the thermal energy can be harnessed to produce electricity or to do other useful work. Typically

23214-401: The terrorists had spied on the nuclear power plants, and several employees had their access privileges withdrawn. Moreover, "nuclear terrorism", for instance with a so-called "Dirty bomb," poses a considerable potential hazard. In many countries, plants are often located on the coast, in order to provide a ready source of cooling water for the essential service water system . As a consequence

23373-417: The then-current use rate. Light water reactors make relatively inefficient use of nuclear fuel, mostly using only the very rare uranium-235 isotope. Nuclear reprocessing can make this waste reusable, and newer reactors also achieve a more efficient use of the available resources than older ones. With a pure fast reactor fuel cycle with a burn up of all the uranium and actinides (which presently make up

23532-477: The turbine generator can power the station's loads while the station is online, without requiring external power. This is achieved via station service transformers which tap power from the generator output before they reach the step-up transformer. 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

23691-524: The use of a thorium fuel cycle in the third stage, as it has abundant thorium reserves but little uranium. Nuclear decommissioning is the process of dismantling a nuclear facility to the point that it no longer requires measures for radiation protection, returning the facility and its parts to a safe enough level to be entrusted for other uses. Due to the presence of radioactive materials, nuclear decommissioning presents technical and economic challenges. The costs of decommissioning are generally spread over

23850-457: The vast majority of electricity from nuclear power is produced by nuclear fission of uranium and plutonium in nuclear power plants . Nuclear decay processes are used in niche applications such as radioisotope thermoelectric generators in some space probes such as Voyager 2 . Reactors producing controlled fusion power have been operated since 1958, but have yet to generate net power and are not expected to be commercially available in

24009-406: 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. Nuclear power facilities are active in 32 countries or regions, and their influence extends beyond these nations through regional transmission grids, especially in Europe. In 2022, nuclear power plants generated 2545 terawatt-hours (TWh) of electricity,

24168-559: Was 5% in 2019 and observers have cautioned that, along with the risks, the changing economics of energy generation may cause new nuclear energy plants to "no longer make sense in a world that is leaning toward cheaper, more reliable renewable energy". In October 2021, the Japanese cabinet approved the new Plan for Electricity Generation to 2030 prepared by the Agency for Natural Resources and Energy (ANRE) and an advisory committee, following public consultation. The nuclear target for 2030 requires

24327-461: Was connected to the national power grid on 27 August 1956. In common with a number of other generation I reactors , the plant had the dual purpose of producing electricity and plutonium-239 , the latter for the nascent nuclear weapons program in Britain . The total global installed nuclear capacity initially rose relatively quickly, rising from less than 1 gigawatt (GW) in 1960 to 100   GW in

24486-399: Was created as a direct outcome of the 1986 Chernobyl accident. The Chernobyl disaster played a major part in the reduction in the number of new plant constructions in the following years. Influenced by these events, Italy voted against nuclear power in a 1987 referendum, becoming the first country to completely phase out nuclear power in 1990. In the early 2000s, nuclear energy was expecting

24645-420: Was estimated that with seawater extraction, there was likely five billion years' worth of uranium resources for use in breeder reactors. Breeder technology has been used in several reactors, but as of 2006, the high cost of reprocessing fuel safely requires uranium prices of more than US$ 200/kg before becoming justified economically. Breeder reactors are however being developed for their potential to burn all of

24804-673: Was generated for the first time by a nuclear reactor on December 20, 1951, at the EBR-I experimental station near Arco, Idaho , which initially produced about 100   kW . In 1953, American President Dwight Eisenhower gave his " Atoms for Peace " speech at the United Nations , emphasizing the need to develop "peaceful" uses of nuclear power quickly. This was followed by the Atomic Energy Act of 1954 which allowed rapid declassification of U.S. reactor technology and encouraged development by

24963-428: Was inevitable that they would eventually suffer what he termed a 'normal accident'. Therefore, he suggested, we might do better to contemplate a radical redesign, or if that was not possible, to abandon such technology entirely. A fundamental issue contributing to a nuclear power system's complexity is its extremely long lifetime. The timeframe from the start of construction of a commercial nuclear power station through

25122-477: Was not targeted by sanctions. However, some countries, especially in Europe, scaled back or cancelled planned nuclear power plants that were to be built by Rosatom. 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

25281-421: Was terminated in midstream because it "smacked too much of underlying danger." Though Japan is a major power in robotics, it had none to send in to Fukushima during the disaster. He mentions that Japan's Nuclear Safety Commission stipulated in its safety guidelines for light-water nuclear facilities that "the potential for extended loss of power need not be considered." However, this kind of extended loss of power to

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