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. Generating electricity from fusion power remains the focus of international research.
The Leibstadt Nuclear Power Plant in Switzerland
Most 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 3 years. It is then cooled for several years in on-site spent fuel pools before being transferred to long term storage. The spent fuel, though low in volume, is high-level radioactive waste. While its radioactivity decreases exponentially it must be isolated from the biosphere for hundreds of thousands of years, though newer technologies (like fast reactors) have the potential to reduce this significantly. Because the spent fuel is still mostly composed of fissionable material, some countries (France and Russia) reprocess their spent fuel by removing the neutron absorbing portion and other wastes (thereby recycling about 90% of the volume), although this process 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 proliferation risk.
The first nuclear power plant was built in the 1950s, and the global installed nuclear capacity grew to 100 GW in the late 1970s, and then grew rapidly during 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 plants. These factors, along with high cost of construction, resulted in the global installed capacity only increasing to 390 GW by 2022. These plants supplied 2,586 terawatt hours (TWh) of electricity in 2019, equivalent to about 10% of global electricity generation, and were the second-largest low-carbon power source after hydroelectricity. As of March 2022, there are 439 civilian fission reactors in the world, 56 under construction and 96 planned, with a combined capacity of 62 GW and 96 GW, respectively. The United States has the largest fleet of nuclear reactors, generating over 800 TWh of zero-emissions electricity per year with an average capacity factor of 92%. Most reactors under construction are generation III reactors in Asia.
Nuclear power has one of the lowest levels of fatalities per unit of energy generated compared to other energy sources. Coal, petroleum, natural gas and hydroelectricity each have caused more fatalities per unit of energy due to air pollution and accidents. Nuclear power plants emit no greenhouse gasses. One of the dangers of nuclear power is the potential for accidents like the Fukushima nuclear disaster in Japan in 2011.
There is a debate about nuclear power. Proponents contend that nuclear power is a safe, sustainable energy source that reduces carbon emissions. The anti-nuclear movement contends that nuclear power poses many threats to people and the environment and is too expensive and slow to deploy when compared to alternative sustainable energy sources.
History
The first light bulbs ever lit by electricity generated by nuclear power at EBR-1 at Argonne National Laboratory-West, December 20, 1951.
The discovery of nuclear fission occurred in 1938 following over four decades of work on 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 of nuclear fission research, just on the cusp of World War II, for the development of 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, 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 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, with the atomic bombings of Hiroshima and Nagasaki taking place one month later.
The launching ceremony of the USS Nautilus January 1954. In 1958 it would become the first vessel to reach the North Pole.
The Calder Hall nuclear power station in the United Kingdom, the world's first commercial nuclear power station.
Despite the military nature of the first nuclear devices, the 1940s and 1950s were characterized by strong optimism for the potential of nuclear power to provide cheap and endless energy.Electricity 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 the private sector.
First power generation
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 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 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.
Expansion and first opposition
The total global installed nuclear capacity initially rose relatively quickly, rising from less than 1 gigawatt (GW) in 1960 to 100 GW in 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 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.[14] France would construct 25 nuclear power plants over the next 15 years,[15][16] 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 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 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, regulations and increased requirements for safety equipment, which made new construction much more expensive. In the United States, over 120 LWR 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.
Chernobyl and renaissance
The town of Pripyat abandoned since 1986, with the Chernobyl plant and the
Olkiluoto 3 under construction in 2009. It was the first EPR, a modernized PWR design, to start construction.
During the 1980s one new nuclear reactor started up every 17 days on average. By the end of the decade, global installed nuclear capacity reached 300 GW. Since the late 1980s, new capacity additions slowed down 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 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 Soviet rubles (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), 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 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, although encountering problems and delays, and going significantly over budget.
Net electrical generation by source and growth from 1980. In terms of energy generated between 1980 and 2010, the contribution from fission grew the fastest.
Electricity production in France, showing the shift to nuclear power. thermofossil
hydroelectric
nuclear
Other renewables
*
The rate of new reactor constructions essentially halted in the late 1980s. Increased capacity factor in existing reactors was primarily responsible for the continuing increase in electrical energy produced during this period.
Electricity generation trends in the top five fission-energy producing countries (US EIA data)
Fukushima
Nuclear power generation (TWh) and operational nuclear reactors since 1997
Prospects of a nuclear renaissance were delayed by another nuclear accident. The 2011 Fukushima Daiichi nuclear accident was caused by a large tsunami triggered by the Tōhoku earthquake, one of 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 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.
Current prospects
By 2015, the IAEA's outlook for nuclear energy had become more promising, recognizing 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 the predicted increase was expected to be in Asia . As of 2018, there are over 150 nuclear reactors planned including 50 under construction.[48] In January 2019, China had 45 reactors in operation, 13 under construction, and plans 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 was 5% in 2019and 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".
Nuclear power plants
An animation of a pressurized water reactor in operation
Number of electricity-generating civilian reactors by type as of 2014[53]
PWR BWR GCR PHWR LWGR FBR
Main articles: Nuclear power plant and Nuclear reactor
See also: List of nuclear reactors and List of nuclear power stations
Nuclear power plants are thermal power stations that generate electricity by harnessing 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.[54]
When a neutron hits the nucleus of a uranium-235 or plutonium atom, it can split the nucleus into two smaller nuclei. The reaction is called nuclear fission. The fission 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, the reaction rate is controlled 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 down changes in reaction rates and gives time for moving the control rods to adjust the reaction rate.[54][55]
Life cycle of nuclear fuel
The nuclear fuel cycle begins when uranium is mined, enriched, and manufactured into nuclear fuel which is delivered to a nuclear power plant. After use, the spent fuel is delivered to a reprocessing plant or to a final repository. In nuclear reprocessing 95% of spent fuel can potentially be recycled to be returned to use in a power plant
Main articles: Nuclear fuel cycle and Integrated Nuclear Fuel Cycle Information System
The life cycle of nuclear fuel starts with uranium mining. The uranium ore is then converted into a compact ore concentrate form, known as yellowcake (U3O8), to facilitate transport. Fission reactors generally need uranium-235, a fissile isotope of uranium. The concentration of uranium-235 in natural uranium is very 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, 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 (UO2), a ceramic, that is then compressively sintered into fuel pellets, a stack of which forms fuel rods of the proper composition and geometry for 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 resources
Proportions of the isotopes uranium-238 (blue) and uranium-235 (red) found in natural uranium and in enriched uranium for different applications. Light water reactors use 3-5% enriched uranium, while CANDU reactors work with natural uranium.
Uranium 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 high concentrations. Uranium mining can be underground, open-pit, or in-situ leach mining. An increasing number of 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$130/kg, were enough to last for between 70 and 100 years.[59][60][61] In 2007, the OECD estimated 670 years of economically recoverable uranium in total conventional resources and phosphate ores assuming the then-current use rate.
Light water reactors make relatively inefficient use of nuclear fuel, mostly using only the very rare uranium-235 isotope.Nuclear reprocessing can make this waste reusable, and newer reactors also achieve a more efficient use of the available resources than older ones.[63] With a pure fast reactor fuel cycle with a burn up of all the uranium and actinides (which presently make up the most hazardous substances in nuclear waste), there is an estimated 160,000 years worth of uranium in total conventional resources and phosphate ore at the price of 60–100 US$/kg.However, reprocessing is expensive, possibly dangerous and can be used to manufacture nuclear weapons.One analysis found that for uranium prices could increase by two orders of magnitudes between 2035 and 2100 and that there could be 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 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 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.[88] Some commentators have argued that this strengthens the case for nuclear power to be considered a renewable energy.[90]
Nuclear waste
Typical composition of uranium dioxide fuel before and after approximately 3 years in the once-through nuclear fuel cycle of a LWR.
The normal operation of nuclear power plants and facilities produce radioactive waste, or nuclear waste. This type of waste is also produced during plant decommissioning. There are two broad categories of nuclear waste: low-level waste and high-level waste.[92] 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.[92]
High-level waste
Activity of spent UOx fuel in comparison to the activity of natural uranium ore over time.
Dry cask storage vessels storing spent nuclear fuel assemblies
The most important waste stream from nuclear power reactors is spent nuclear fuel, which is considered high-level waste. For 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 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 6 to 10 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, 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 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).[104] Some proposed reactor designs, such as 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 a reactor. Spent thorium fuel, although more difficult to handle than spent uranium fuel, may present somewhat lower proliferation risks.
Low-level waste
Main article: Low-level waste
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 a low-level waste disposal site.
Waste relative to other types
See also: Radioactive waste § Naturally occurring radioactive material
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.[63] 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 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 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 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.
Waste disposal
Nuclear waste flasks generated by the United States during the Cold War are stored underground at the Waste Isolation Pilot Plant (WIPP) in New Mexico. The facility is seen as a potential demonstration for storing spent fuel from civilian reactors.
Following interim storage in a spent fuel pool, the bundles of used fuel rod assemblies of 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.With the lack of movement of nuclear waste in the 2 billion year old natural nuclear fission reactors in Oklo, Gabon being 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.
Most waste packaging, small-scale experimental fuel recycling chemistry and radiopharmaceutical refinement is conducted within remote-handled hot cells.
There are no commercial scale purpose built underground high-level waste repositories in operation.However, in Finland the Onkalo spent nuclear fuel repository of the Olkiluoto Nuclear Power Plant is under construction as of 2015.
Reprocessing
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 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 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 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 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 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 the majority from France, 17% from Germany, and 9% from Japan.
Breeding
Nuclear fuel assemblies being inspected before entering a pressurized water reactor in the United States.
Main articles: Breeder reactor and Nuclear power proposed as renewable energy
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 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 up all of 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 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 the use of a thorium fuel cycle in the third stage, as it has abundant thorium reserves but little uranium.
Nuclear decommissioning
Main article: Nuclear decommissioning
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 the lifetime of a facility and saved in a decommissioning fund.
How to survive a tactical nuclear bomb? Defence experts explaining .
Ignition
You see a sudden flash in the sky, as bright as (or even brighter than) the sun. You quickly turn your face away and run for cover.
The brightness suddenly vanishes, but returns again a short while later and continues – the distinctive double flash caused by competition between the fireball and shock wave. It gets incredibly hot and bright, and you shield your eyes to avoid retina burns.
The intense thermal radiation also causes skin burns, possibly through your clothing. Wearing pale-coloured clothing or being indoors will help.
You've also received substantial doses of invisible nuclear radiation: gamma rays, X-rays and neutrons. You find cover to shield the worst of the heat and radiation.
You've now survived the first seconds of a nuclear detonation, hopefully a "tactical" bomb smaller than that at Hiroshima (which was the equivalent of 15 kilotons of TNT).
The fact you've lived this long means you're on the periphery, not at ground zero. But to survive the next few seconds, there's a few things you'll need to do.
The blast wave
Next will come the blast wave. This consists of an overpressure shock wave followed by an outward blast wind, often with reverse winds returning to ground zero.
This will destroy or damage all built structures within a certain radius from the epicentre, depending on the yield and height of the burst.
For example, a 15 kiloton bomb would have a fireball radius of about 100 metres and cause complete destruction up to 1.6 kilometres around the epicentre.
A one kiloton bomb – similar to the 2020 ammonium nitrate explosion in the Lebanese capital Beirut – would have a fireball radius of about 50 metres, with severe damage to about 400 metres.
The shock wave travels faster than the speed of sound (about 343 metres per second). So if you're one kilometre away from the epicentre, you have less than three seconds to find cover. If you're five kilometres away, you have less than 15 seconds.
You'll need to shield yourself from the thermal and nuclear radiation, as you could die if exposed. However, you must find somewhere safe – you don't want to be crushed in a building destroyed by the blast wave.
Get indoors, and preferably into a reinforced bunker or basement. If you're in a brick or concrete house with no basement, find a strong part of the building. In Australia, this would be a small bathroom at ground level, or a laundry with brick walls.
The incoming shock wave will reflect off the internal walls, superimposing with the original to double the pressure. Avoid the explosion side of the building and make sure to lie down rather than stand.
If there is no reinforced room, you can lie under a sturdy table or next to (not under) a bed or sofa. You may be crushed under a bed or sofa if a concrete slab crashes down.
Keep away from doors, tall furniture and windows, as they will probably shatter. If the walls come down, you'll have a chance of surviving in a pocket in the rubble.
If you're in an apartment building, run to the fire staircase in the structural core of the building.
Avoid timber, fibre cement or prefabricated structures (which includes most modern housing in Australia) as these probably won't survive. And open your jaw as the blast comes through, so your eardrums get the pressure wave on both sides.
Radioactive fallout
The third stage is the fallout: a cloud of toxic radioactive particles from the bomb will be uplifted during the blast and deposited by the wind, contaminating everything in its path. This will continue for hours after the explosion, or possibly days.
In comparable British-Australian bomb tests at Maralinga, the fallout was clearly preserved in the desert along one kilometre-wide tracks, extending 5–25 kilometres out from ground zero.
You must protect yourself from the fallout or you'll have a short life.
If you're in a stable structure such as a basement or fire staircase, you can shelter in place for a few days, if necessary. If your building is destroyed, you'll need to move to a nearby intact structure.
Block all the doors, windows and air gaps. You can drink water from intact pipes and eat from sealed cans.
For outdoor movement, any PPE available should be used – especially a P2 mask, or even a dust mask. While tactical nukes are designed to destroy personnel or infrastructure, they still allow troop movement under cover of the blast. The radiological hazard is significant, but should be survivable.
A radiological weapon, on the other hand, will deliberately increase the radiation dose to the point of it being lethal.
Once you've found shelter, you'll need to decontaminate. This will require a thorough scrub of the skin, nails and hair, and a change into clean clothing. But any severe burns should be tended to first.
Hopefully by now the national authorities will have stepped in for rescue and medical treatment.
Nuclear Weapons Solutions
The only way to completely eliminate nuclear risks is to eliminate nuclear weapons from the planet.
TABLE OF CONTENTS
2,400 US nuclear weapons slated for dismantlement
Roughly 9,000 nuclear weapons are hidden away in bunkers and missile siloes, stored in warehouses, at airfields and naval bases, and carried by dozens of submarines across the world.
A single warhead can demolish a city center. A full-fledged nuclear war would threaten life as we know it.
But the risk of nuclear war isn't fixed; with the right policies and safeguards, we can help protect against mistakes, accidents, and poor decision-making—and we can work toward a world free from the nuclear threat.
No-first-use
EXPLAINER
unarmed Minuteman III intercontinental ballistic missile test launch from Vandenberg Air Force Base, Calif. (
No First Use Explained
What's a No First Use (NFU) Nuclear Policy and would adopting one make the United States safer?
Nuclear weapons are meant to deter nuclear attacks from other countries. However, current policy allows the United States to begin a nuclear war by being the first to use nuclear weapons in a conflict—in response to a non-nuclear attack by North Korea, Russia, or China. A "no-first-use" policy would take this option off the table. The United States could pledge that it will never be the first to use a nuclear weapon, regardless of the circumstances. Doing so would reduce the risk of miscalculation during a crisis, and limit the possibility of a smaller, non-nuclear conflict escalating into a nuclear one. Without no-first-use, the US public is at risk of a devastating retaliatory attack, should the United States ever cross the threshold and start a nuclear war.
Sole authority
REPORT
Minuteman III ICBM being launched over the Pacific Ocean
Whose Finger Is on the Button?
In the United States, a single person is authorized to make the decision to use a nuclear weapon—the president.
In the United States, the president is singlehandedly responsible for the decision to launch a nuclear weapon. They are not required to consult with anyone, and no one carries the authority to stop a legal launch order once given.
This system of control (known as "sole authority") isn't the only way to handle launch decisions. Other officials could securely be included in the decision, providing checks and balances and a basic defense against mistakes, accidents, miscalculations, and recklessness.
De-alerting
EXPLAINER
What is Hair-Trigger Alert?
Hundreds of US nuclear warheads are kept ready to launch within minutes—making us less safe, not safer.
Currently, 400 nuclear-tipped missiles in the US heartland are kept on "hair-trigger alert." If sensors show an incoming nuclear attack that threatens these missiles, it's US policy to alert the president, who would need to order their almost immediate launch to prevent them from being destroyed—before the attack is confirmed as real.
But sensors can be wrong. A long list of nuclear close calls—which include technical malfunctions, miscommunications, and plain bad luck—shows how close we've come to mistakenly starting nuclear war.
Taking these missiles off hair-trigger alert (or "de-alerting") would immediately remove the risk of a mistaken or accidental launch, while preserving our ability to retaliate with missiles on submarines hidden at sea.
Smarter spending
REPORT
Airmen from the 90th Missile Maintenance Squadron prepare a reentry system for removal from a launch facility
Rethinking ICBMs
The US continues to keep intercontinental ballistic missiles on high alert—creating the risk of a mistaken nuclear war in response to a false warning.
The United States is currently planning to spend an estimated $1.7 trillion dollars over the next three decades to maintain and replace its entire nuclear arsenal with new weapons, including nuclear-armed bombers, missiles, and submarines.
Such a tremendous investment of money and effort is unnecessary. It also encourages Russia to build more capable weapons of its own, accelerating an emerging and destabilizing international arms race.
Instead, the United States should eliminate some types of nuclear weapons, refurbish the remaining weapons where possible, and make any necessary replacements without enhancing capabilities.
International agreements
A total of nine countries possess nuclear weapons. Reducing the risk of nuclear war will require domestic policy changes within all those countries, as well as cooperation and verified agreements between them.
Diplomacy has a strong track record. Multiple treaties and agreements—and decades of dialogue and cooperation—helped reduce US and Soviet arsenals from a high of 64,000 warheads in the 1980s to a total of around 8,000 today.
The Biden administration's wise decision to extend the New Strategic Arms Reduction Treaty (New START) was a critical important step in arms control.
The United States can build on that success by committing to a "diplomacy first" approach with North Korea; and rejoining the Iran Deal, which limits Iran's capacity to produce weapons-grade uranium.
Taking Measures to Protect Nuclear Weapons, Space Assets
The Defense Department relies on nuclear-armed bombers, submarines and intercontinental ballistic missiles, as well as space-based sensors, to provide a strategic deterrence umbrella for the homeland and to protect deployed forces, allies and partners.
However, sensitive microelectronics used in these assets could be vulnerable to high levels of ionizing radiation caused by a number of factors, including cosmic rays in outer space, severe solar storms, and an electromagnetic pulse caused by a high-altitude nuclear detonation.
Men work on satellite communications.
To protect against these threats, the DOD has developed techniques to protect microelectronics used in satellites, spacecraft, the nuclear triad and the triad's command and control center, said Rich Ryan, director for international programs, nuclear forensics, resiliency and survivability in the office of the deputy assistant secretary of defense for nuclear matters.
This protection, known as hardening, can consist of manufacturing chips on insulated material, redundant circuits, altering the design of circuits, and placing a shield over the microelectronics, he said.
Spotlight: Science and Technology
Each of the methods used undergoes rigorous radiation testing in military and government laboratories to ensure they work in hazardous conditions, he said.
A vessel flies in space.
In the past, there was no central repository for identifying and accessing parts that have been certified as radiation hardened, he said.
On Sept. 30, the DOD opened a parts library to serve the department and other agencies with requirements for radiation hardened parts, including NASA and the Department of Energy. The cloud-based library is hosted by Nimbis Services in Oro Valley, Arizona.
Spotlight: DOD Space Strategy
Known as the Trusted Silicon Stratus Distributed Transition Environment, the authority to operate this library was issued by the Strategic Radiation Hardened Electronics Council; the Air Force Research Laboratory at Wright Patterson Air Force Base, Ohio; and the Naval Surface Warfare Center Crane Division in Indiana.
"The authorization comes as a clarion call that in order to improve supply chain visibility across the nuclear enterprise, establishing this microelectronics library is key to improving the ability to analyze key parts, their sources, and to facilitate government re-use of intellectual property throughout the DOD," Ryan said.
A rocket launches.
The next step for the parts library is to test performance across DOD programs, he added.
"The parts library will enable closer Air Force, Navy and Missile Defense Agency collaboration on a variety of strategic system acquisition and sustainment programs — allowing them to better align requirements, technology development, production and sustainment efforts, and supply chain protection activities. By improving data-sharing and reducing duplication of effort, the library will drive affordability, advance technology, and reduce risk while protecting critical design information," said Drew Walter, deputy assistant secretary of defense for nuclear matters.
Nuclear weapons: Why reducing the risk of nuclear war should be a key concern of our generation
The consequences of nuclear war would be devastating. Much more should – and can – be done to reduce the risk that humanity will ever fight such a war.
by Max Roser
March 03, 2022
The shockwave and heat that the detonation of a single nuclear weapon creates can end the lives of millions of people immediately.
But even larger is the devastation that would follow a nuclear war.
The first reason for this is nuclear fallout. Radioactive dust from the detonating bombs rises up into the atmosphere and spreads out over large areas of the world from where it falls down and causes deadly levels of radiation.
The second reason is less widely known. But this consequence – 'nuclear winter' and the worldwide famine that would follow – is now believed to be the most serious consequence of nuclear war.
Cities that are attacked by nuclear missiles burn at such an intensity that they create their own wind system, a firestorm: hot air above the burning city ascends and is replaced by air that rushes in from all directions. The storm-force winds fan the flames and create immense heat.
From this firestorm large columns of smoke and soot rise up above the burning cities and travel all the way up to the stratosphere. There it spreads around the planet and blocks the sun's light. At that great height – far above the clouds – it cannot be rained out, meaning that it will remain there for years, darkening the sky and thereby drying and chilling the planet.
The nuclear winter that would follow a large-scale nuclear war is expected to lead to temperature declines of 20 or even 30 degrees Celsius (60–86° F) in many of the world's agricultural regions – including much of Eurasia and North America. Nuclear winter would cause a 'nuclear famine'. The world's food production would fail and billions of people would starve.1
These consequences – nuclear fallout and nuclear winter leading to famine – mean that the destruction caused by nuclear weapons is not contained to the battlefield. It would not just harm the attacked country. Nuclear war would devastate all countries, including the attacker.
The possibility of global devastation is what makes the prospect of nuclear war so very terrifying. And it is also why nuclear weapons are so unattractive for warfare. A weapon that can lead to self-destruction is not a weapon that can be used strategically.
US President Reagan put it in clear words at the height of the Cold War: "A nuclear war cannot be won and must never be fought. The only value in our two nations possessing nuclear weapons is to make sure they will never be used. But then would it not be better to do away with them entirely?"2
Nuclear stockpiles have been reduced, but the risk remains high
40 years after Reagan's words, the Cold War is over and nuclear stockpiles have been reduced considerably, as the chart shows.
The world has learned that nuclear armament is not the one-way street that it was once believed to be. Disarmament is possible.
But the chart also shows that there are still almost ten thousand nuclear weapons distributed among nine countries on our planet, at least.3 Each of these weapons can cause enormous destruction; many are much larger than the ones that the US dropped on Hiroshima and Nagasaki.4
Collectively these weapons are immensely destructive. The nuclear winter scenario outlined above would kill billions of people—billions—in the years that follow a large-scale nuclear war, even if it was fought "only" with today's reduced stockpiles.5
It is unclear whether humanity as a species could possibly survive a full-scale nuclear war with the current stockpiles.6 A nuclear war might well be humanity's final war.
Estimated nuclear warhead stockpiles, 1945 to 2022
Stockpiles include warheads assigned to military forces, but exclude warheads queued for dismantlement.
Close Calls: Instances that threatened to push the 'balance of terror' out of balance and into war
The 'balance of terror' is the idea that all involved political leaders are so scared of nuclear war that they never launch a nuclear attack.
If this is achievable at all, it can only be achieved if all nuclear powers keep their weapons in check. This is because the balance is vulnerable to accidents: a nuclear bomb that detonates accidentally – or even just a false alarm, with no weapons even involved – can trigger nuclear retaliation because several countries keep their nuclear weapons on 'launch on warning'; in response to a warning, their leaders can decide within minutes whether they want to launch a retaliatory strike.
For the balance of terror to be a balance, all parties need to be in control at all times. This however is not the case.
In the timeline, you can read through some of the close calls during the past decades.
The risk of nuclear war might well be low – because neither side would want to fight such a war that would have such awful consequences for everyone on the planet. But there is a risk that the kinds of technical errors and accidents listed here could lead accidentally to the use of nuclear weapons, as a nuclear power can incorrectly come to believe that they are under attack.
This is why false alarms, errors, and close calls are so crucial to monitor: they are the incidents that can push the 'balance of terror' out of balance and into war.
Accidents and errors are of course not the only possible path that could lead to the use of nuclear weapons. There is the risk of a terribly irresponsible person leading a country possessing nuclear weapons. There is the risk of nuclear terrorism, possibly after a terrorist organization steals weapons. There is the possibility that hackers can take control of the nuclear chain of command. And there is the possibility that several of these factors play a role at the same time.
A timeline of nuclear weapons 'close calls'7
Below this post, you find additional lists of close calls, where you find much more information on each of these incidents.