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99-685: On 13 December 2017, the Hiroshima High Court issued a temporary injunction to halt the operation of the Ikata 3 nuclear reactor until September 2018. The injunction was revoked in March 2021 and Ikata 3 was restarted in December 2021. The plant is on a site with an area of 86 hectares (210 acres); 47% of the plant site is green, in comparison the non-nuclear plants Shikoku Electric operates are 13.8, 20.1, 21.2 and 45.5%. On 3 March 2004, there

198-403: 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,

297-496: 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

396-520: A chain reaction (meaning it is fissile), including uranium, plutonium , and more exotic transuranic fuels. This fuel content is often referred to as the heavy metal to distinguish it from other metals present in the fuel, such as those used for cladding . The heavy metal is typically present as either metal or oxide, but other compounds such as carbides or other salts are possible. Generation II reactors were typically designed to achieve about 40 GWd/tU. With newer fuel technology, and particularly

495-618: A fuel charge. In reactors with online refuelling , fuel elements can be repositioned during operation to help achieve this. In reactors without this facility, fine positioning of control rods to balance reactivity within the core, and repositioning of remaining fuel during shutdowns in which only part of the fuel charge is replaced may be used. On the other hand, there are signs that increasing burnup above 50 or 60 GWd/tU leads to significant engineering challenges and that it does not necessarily lead to economic benefits. Higher-burnup fuels require higher initial enrichment to sustain reactivity. Since

594-410: 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

693-533: 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

792-1087: 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

891-405: 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

990-444: A solid form for use or disposal in a further step if desired. If tritium has not been removed from the fuel in a step prior to this aqueous extraction, the water used in this process will be contaminated, requiring expensive isotope separation or allowing the tritium to decay to safe levels before the water can be released into the biosphere. Burnup is one of the key factors determining the isotopic composition of spent nuclear fuel ,

1089-540: A stress test was required for all suspended reactors by the government, after the accidents in Fukushima. The Ehime prefectural government said it would decide whether to approve the resumption of operations after the results of the safety test came out. The Shikoku Electric Power Company said that if the No. 3 reactor did not resume operations, power supplies would be very tight in winter when electricity demand would be high. It

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1188-425: 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

1287-429: A very long half life, constitutes 5% of fission products, but can be alloyed with uranium and transuranics during fuel recycling, or used in zircalloy cladding, where its radioactivity is irrelevant. The remaining 20% of fission products, or 1% of unprocessed fuel, for which the longest-lived isotopes are Cs and Sr , require special custody for only 300 years. Therefore, the mass of material needing special custody

1386-490: 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

1485-408: 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

1584-482: Is 1% of the mass of unprocessed used fuel. In the case of Cs or Sr this "special custody" could also take the form of use for food irradiation or as fuel in a radioisotope thermoelectric generator . As both the native elements strontium and caesium and their oxides—chemical forms in which they can be found in oxide or metal fuel—form soluble hydroxides upon reaction with water, they can be extracted from spent fuel relatively easily and precipitated into

1683-725: 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

1782-486: 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

1881-461: 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

1980-489: 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

2079-498: 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),

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2178-410: 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

2277-621: 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

2376-405: 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

2475-400: Is measured as the fraction of fuel atoms that underwent fission in %FIMA (fissions per initial metal atom) or %FIFA (fissions per initial fissile atom) as well as, preferably, the actual energy released per mass of initial fuel in gigawatt -days/ metric ton of heavy metal (GWd/tHM), or similar units. Expressed as a percentage: if 5% of the initial heavy metal atoms have undergone fission,

2574-424: 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

2673-521: 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

2772-478: 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

2871-689: Is not closely related to burnup. High-burnup fuel generates a smaller volume of fuel for reprocessing, but with a higher specific activity . Unprocessed used fuel from current light-water reactors consists of 5% fission products and 95% actinides (most of it uranium), and is dangerously radiotoxic, requiring special custody, for 300,000 years. Most of the long-term radiotoxic elements are transuranic, and therefore could be recycled as fuel. 70% of fission products are either stable or have half lives less than one year. Another six percent ( I and Tc ) can be transmuted to elements with extremely short half lives ( I : 12.36 hours; Tc : 15.46 seconds). Zr , having

2970-448: Is possible in principle to remove plutonium from used fuel and divert it to weapons usage, in practice there are formidable obstacles to doing so. First, fission products must be removed. Second, plutonium must be separated from other actinides. Third, fissionable isotopes of plutonium must be separated from non-fissionable isotopes, which is more difficult than separating fissionable from non-fissionable isotopes of uranium, not least because

3069-417: Is predominantly from medium-lived fission products , particularly Cs (30.08 year half life) and Sr (28.9 year half life). As there are proportionately more of these in high-burnup fuel, the heat generated by the spent fuel is roughly constant for a given amount of energy generated. Similarly, in fuel cycles with nuclear reprocessing , the amount of high-level waste for a given amount of energy generated

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3168-511: Is reprocessed on-site, as proposed for the Integral Fast Reactor , opportunities for diversion are further limited. Therefore, production of plutonium during civilian electric power reactor operation is not a significant problem. One 2003 MIT graduate student thesis concludes that "the fuel cycle cost associated with a burnup level of 100 GWd/tHM is higher than for a burnup of 50 GWd/tHM. In addition, expenses will be required for

3267-617: 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

3366-458: 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,

3465-474: The EBR-II reactor at Argonne National Laboratory took metallic fuel up to 19.9% burnup, or just under 200 GWd/t. The Deep Burn Modular Helium Reactor (DB-MHR) might reach 500 GWd/t of transuranic elements . In a power station, high fuel burnup is desirable for: It is also desirable that burnup should be as uniform as possible both within individual fuel elements and from one element to another within

3564-540: 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

3663-439: 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

3762-422: 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

3861-642: 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

3960-766: 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

4059-507: 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

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4158-622: 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

4257-585: 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

4356-401: 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

4455-640: 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

4554-475: The amount of separative work units (SWUs) is not a linear function of enrichment, it is more expensive to achieve higher enrichments. There are also operational aspects of high burnup fuels that are associated especially with reliability of such fuel. The main concerns associated with high burnup fuels are: In once-through nuclear fuel cycles such as are currently in use in much of the world, used fuel elements are disposed of whole as high level nuclear waste, and

4653-571: The area round the nuclear power plant, with buses, helicopters and boats of the Maritime Self-Defense Force. The residents in the town of Ikata, commanded by disaster announcements on the radio to gather at a junior high school. From there they were taken by buses to a shelter some 50 kilometers further. This drill was the first executed on this scale, and it was also the first time that so many people were evacuated out from their town. On 19 April 2016, unit 3 received from NRA

4752-593: 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

4851-702: 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,

4950-559: The burden of proof for risks posed by the nuclear plant. The plant operator then planned to restart the reactor in October. Unit 3 was eventually restarted on 2 December 2021. In the film Godzilla vs. Destoroyah (1995), Godzilla , suffering from nuclear meltdown, approached the nuclear plant for energy, emerging from below the surface of the Bungo Channel . The Japan Self Defense Forces are deployed to stall Godzilla and defend

5049-400: The burnup is 5%FIMA. If these 5% were the total of U that were in the fuel at the beginning, the burnup is 100%FIFA (as U is fissile and the other 95% heavy metals like U are not). In reactor operations, this percentage is difficult to measure, so the alternative definition is preferred. This can be computed by multiplying the thermal power of the plant by the time of operation and dividing by

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5148-415: 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

5247-747: 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

5346-409: 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

5445-492: The development of fuels capable of sustaining such high levels of irradiation. Under current conditions, the benefits of high burnup (lower spent fuel and plutonium discharge rates, degraded plutonium isotopics) are not rewarded. Hence there is no incentive for nuclear power plant operators to invest in high burnup fuels." A study sponsored by the Nuclear Energy University Programs investigated

5544-472: 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

5643-753: The economic and technical feasibility, in the longer term, of higher burnup. 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, 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

5742-536: The evaluation of earthquake risk under the stricter post Fukushima regulations. In January 2020 the High Court passed a further injunction against the operation of unit 3, again in part because an active fault nearby could not be ruled out as a full geological survey of the area had not been conducted. In March 2021, the Hiroshima High Court revoked the injunction, following an appeal by the plant operator, clearing it to resume operations. The court said residents bear

5841-488: The facility, fearing that a direct attack against him could cause a nuclear explosion and destroy the planet. Thankfully, the Super X-III aircraft comes to the rescue and temporarily freezes Godzilla before he can begin attacking the power plant. Burnup In nuclear power technology, burnup (also known as fuel utilization ) is a measure of how much energy is extracted from a primary nuclear fuel source. It

5940-449: The final approval to restarting. On 27 June, Shikoku Electric completed loading 157 fuel assemblies, of which 16 uranium-plutonium mixed oxide (MOX) . Unit 3 achieved criticality on 13 August and resumed commercial service on 7 September. However, on 13 December 2017 the Hiroshima High Court revoked the lower court decision, ordering the close of the unit until the end of September 2018. Shikoku Electric plans to appeal. The dispute centres on

6039-456: 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

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6138-521: 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

6237-578: 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

6336-425: 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

6435-574: 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

6534-551: 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

6633-516: 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

6732-719: 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

6831-399: The mass difference is one atomic unit instead of three. All processes require operation on strongly radioactive materials. Since there are many simpler ways to make nuclear weapons, nobody has constructed weapons from used civilian electric power reactor fuel, and it is likely that nobody ever will do so. Furthermore, most plutonium produced during operation is fissioned. To the extent that fuel

6930-534: The mass of the initial fuel loading. For example, if a 3000 MW thermal (equivalent to 1000 MW electric at 33.333% efficiency, which is typical of US LWRs) plant uses 24 tonnes of enriched uranium (tU) and operates at full power for 1 year, the average burnup of the fuel is (3000 MW·365 d)/24 metric tonnes = 45.63 GWd/t, or 45,625 MWd/tHM (where HM stands for heavy metal, meaning actinides like thorium, uranium, plutonium, etc.). Converting between percent and energy/mass requires knowledge of κ,

7029-488: 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

7128-437: 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

7227-418: 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

7326-428: 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

7425-432: 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,

7524-416: 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

7623-430: The others being its initial composition and the neutron spectrum of the reactor. Very low fuel burnup is essential for the production of weapons-grade plutonium for nuclear weapons , in order to produce plutonium that is predominantly Pu with the smallest possible proportion of Pu and Pu . Plutonium and other transuranic isotopes are produced from uranium by neutron absorption during reactor operation. While it

7722-469: 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

7821-497: 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

7920-511: 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

8019-630: 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

8118-462: 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

8217-481: The reactor were replaced in order to accommodate more control rods and allow for higher fuel burnup. In 2010, a partial MOX fuel core was loaded into the No.3 reactor for the cycle beginning 24 February 2010. On Sunday 4 September reactor no. 1 was shut down for regular inspections. These check-ups would last at least three months. At that time reactor No.3 was also shut down, although the normal inspections were long time finished before September. To resume operation,

8316-400: The remaining uranium and plutonium content is lost. Higher burnup allows more of the fissile U and of the plutonium bred from the U to be utilised, reducing the uranium requirements of the fuel cycle. In once-through nuclear fuel cycles, higher burnup reduces the number of elements that need to be buried. However, short-term heat emission, one deep geological repository limiting factor,

8415-637: 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

8514-450: 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

8613-512: 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

8712-426: 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

8811-417: 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

8910-502: The thermal energy released per fission event. A typical value is 193.7  MeV ( 3.1 × 10   J ) of thermal energy per fission (see Nuclear fission ). With this value, the maximum burnup of 100%FIMA, which includes fissioning not just fissile content but also the other fissionable nuclides, is equivalent to about 909 GWd/t. Nuclear engineers often use this to roughly approximate 10% burnup as just less than 100 GWd/t. The actual fuel may be any actinide that can support

9009-492: The use of nuclear poisons , these same reactors are now capable of achieving up to 60 GWd/tU. After so many fissions have occurred, the build-up of fission products poisons the chain reaction and the reactor must be shut down and refueled. Some more-advanced light-water reactor designs are expected to achieve over 90 GWd/t of higher-enriched fuel. Fast reactors are more immune to fission-product poisoning and can inherently reach higher burnups in one cycle. In 1985,

9108-524: 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

9207-563: 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

9306-463: Was a coolant leak in Unit 3. On 13 August 2003, the maximum burnup for spent fuel was changed from 48,000 MWd/ton to 55,000 MWd/ton. In January 2006 Mitsubishi Heavy Industries announced the completion of the replacement of the internal structure of the No.1 reactor. It was the world's first all-in-one extraction and replacement of the core internals of a PWR reactor. The upper and lower internals of

9405-466: 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

9504-512: Was considered to restart a thermal power-plant which had been long out of use. In February 2012 an evacuation drill was held in the prefecture Ehime and Shimane. The drill was done to mimic the situation of a reactor cooling failure after a huge earthquake. The evacuation-zones were expanded from 10 to 30 kilometers after the disaster in Fukushima Daiichi nuclear power plant . In this evacuation drill some 10.000 people were taken out of

9603-399: 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

9702-420: 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

9801-692: 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

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