The D1G reactor was a prototype naval reactor designed for the United States Navy to provide electricity generation and propulsion on warships . The D1G designation stands for:
103-875: This prototype nuclear reactor was constructed for the United States Department of Energy 's Office of Naval Reactors as part of the Naval Nuclear Propulsion Program. The reactor was built by General Electric and operated by the Knolls Atomic Power Laboratory at the Kesselring Site Operation in West Milton, New York . It was used for testing components and as a training tool for the Nuclear Power Training Unit. The reactor operated from 1962 to 1996, when it
206-475: A nuclear proliferation risk as they can be configured to produce plutonium , as well as tritium gas used in boosted fission weapons . Reactor spent fuel can be reprocessed to yield up to 25% more nuclear fuel, which can be used in reactors again. Reprocessing can also significantly reduce the volume of nuclear waste, and has been practiced in Europe, Russia, India and Japan. Due to concerns of proliferation risks,
309-553: A " neutron howitzer ") produced a barium residue, which they reasoned was created by fission of the uranium nuclei. In their second publication on nuclear fission in February 1939, Hahn and Strassmann predicted the existence and liberation of additional neutrons during the fission process, opening the possibility of a nuclear chain reaction . Subsequent studies in early 1939 (one of them by Szilárd and Fermi), revealed that several neutrons were indeed released during fission, making available
412-520: A 10%+ compound rate, doubling in abundance every seven years. There are now about 21,000 desalination plants in operation around the globe. The biggest ones are in the United Arab Emirates , Saudi Arabia , and Israel. The world's largest desalination plant is located in Saudi Arabia ( Ras Al-Khair Power and Desalination Plant ) with a capacity of 1,401,000 cubic meters per day. Desalination
515-490: A April 2024, researchers from the Australian National University published experimental results of a novel technique for desalination. This technique, thermodiffusive desalination, passes saline water through a channel with a temperature gradient. Species migrate under this temperature gradient in a process known a thermodiffusion. Researchers then separated the water into fractions. After multiple passes through
618-479: A buffer tank on a hill with seawater. The reverse osmosis process receives its pressurized seawater feed in non-sunlight hours by gravity, resulting in sustainable drinking water production without the need for fossil fuels, an electricity grid or batteries. Nano-tubes are also used for the same function (i.e., Reverse Osmosis). Forward osmosis uses a semi-permeable membrane to effect separation of water from dissolved solutes. The driving force for this separation
721-441: A crucial role in generating large amounts of electricity with low carbon emissions, contributing significantly to the global energy mix. Just as conventional thermal power stations generate electricity by harnessing the thermal energy released from burning fossil fuels , nuclear reactors convert the energy released by controlled nuclear fission into thermal energy for further conversion to mechanical or electrical forms. When
824-681: A decade of regional drought. By the late 1960s and the early 1970s, RO started to show promising results to replace traditional thermal desalination units. Research took place at state universities in California, at the Dow Chemical Company and DuPont . Many studies focus on ways to optimize desalination systems. The first commercial RO plant, the Coalinga desalination plant, was inaugurated in California in 1965 for brackish water . Dr. Sidney Loeb , in conjunction with staff at UCLA , designed
927-445: A gas or a liquid metal (like liquid sodium or lead) or molten salt – is circulated past the reactor core to absorb the heat that it generates. The heat is carried away from the reactor and is then used to generate steam. Most reactor systems employ a cooling system that is physically separated from the water that will be boiled to produce pressurized steam for the turbines , like the pressurized water reactor . However, in some reactors
1030-442: A large fissile atomic nucleus such as uranium-235 , uranium-233 , or plutonium-239 absorbs a neutron, it may undergo nuclear fission. The heavy nucleus splits into two or more lighter nuclei, (the fission products ), releasing kinetic energy , gamma radiation , and free neutrons . A portion of these neutrons may be absorbed by other fissile atoms and trigger further fission events, which release more neutrons, and so on. This
1133-627: A large pilot plant to gather data on RO, but was successful enough to provide freshwater to the residents of Coalinga. This was a milestone in desalination technology, as it proved the feasibility of RO and its advantages compared to existing technologies (efficiency, no phase change required, ambient temperature operation, scalability, and ease of standardization). A few years later, in 1975, the first sea water reverse osmosis desalination plant came into operation. As of 2000, more than 2000 plants were operated. The largest are in Saudi Arabia, Israel, and
SECTION 10
#17328483991431236-424: A less effective moderator. In other reactors, the coolant acts as a poison by absorbing neutrons in the same way that the control rods do. In these reactors, power output can be increased by heating the coolant, which makes it a less dense poison. Nuclear reactors generally have automatic and manual systems to scram the reactor in an emergency shut down. These systems insert large amounts of poison (often boron in
1339-434: A lower temperature, when the ambient atmospheric pressure is less than usual atmospheric pressure. Thus, because of the reduced pressure, low-temperature "waste" heat from electrical power generation or industrial processes can be employed. Water is evaporated and separated from sea water through multi-stage flash distillation , which is a series of flash evaporations . Each subsequent flash process uses energy released from
1442-479: A multidisciplinary desalination methodology in the IBTS Greenhouse . The IBTS is an industrial desalination (power)plant on one side and a greenhouse operating with the natural water cycle (scaled down 1:10) on the other side. The various processes of evaporation and condensation are hosted in low-tech utilities, partly underground and the architectural shape of the building itself. This integrated biotectural system
1545-570: A number of ways: A kilogram of uranium-235 (U-235) converted via nuclear processes releases approximately three million times more energy than a kilogram of coal burned conventionally (7.2 × 10 joules per kilogram of uranium-235 versus 2.4 × 10 joules per kilogram of coal). The fission of one kilogram of uranium-235 releases about 19 billion kilocalories , so the energy released by 1 kg of uranium-235 corresponds to that released by burning 2.7 million kg of coal. A nuclear reactor coolant – usually water but sometimes
1648-461: A patent on reactors on 19 December 1944. Its issuance was delayed for 10 years because of wartime secrecy. "World's first nuclear power plant" is the claim made by signs at the site of the EBR-I , which is now a museum near Arco, Idaho . Originally called "Chicago Pile-4", it was carried out under the direction of Walter Zinn for Argonne National Laboratory . This experimental LMFBR operated by
1751-737: A pile (hence the name) of graphite blocks, embedded in which was natural uranium oxide 'pseudospheres' or 'briquettes'. Soon after the Chicago Pile, the Metallurgical Laboratory developed a number of nuclear reactors for the Manhattan Project starting in 1943. The primary purpose for the largest reactors (located at the Hanford Site in Washington ), was the mass production of plutonium for nuclear weapons. Fermi and Szilard applied for
1854-407: A planned typical lifetime of 30–40 years, though many of those have received renovations and life extensions of 15–20 years. Some believe nuclear power plants can operate for as long as 80 years or longer with proper maintenance and management. While most components of a nuclear power plant, such as steam generators, are replaced when they reach the end of their useful lifetime, the overall lifetime of
1957-471: A reactor. One such process is delayed neutron emission by a number of neutron-rich fission isotopes. These delayed neutrons account for about 0.65% of the total neutrons produced in fission, with the remainder (termed " prompt neutrons ") released immediately upon fission. The fission products which produce delayed neutrons have half-lives for their decay by neutron emission that range from milliseconds to as long as several minutes, and so considerable time
2060-430: A self-sustaining chain reaction . The process is carefully controlled using control rods and neutron moderators to regulate the number of neutrons that continue the reaction, ensuring the reactor operates safely, although inherent control by means of delayed neutrons also plays an important role in reactor output control. The efficiency of nuclear fuel is much higher than fossil fuels; the 5% enriched uranium used in
2163-518: A set of theoretical nuclear reactor designs. These are generally not expected to be available for commercial use before 2040–2050, although the World Nuclear Association suggested that some might enter commercial operation before 2030. Current reactors in operation around the world are generally considered second- or third-generation systems, with the first-generation systems having been retired some time ago. Research into these reactor types
SECTION 20
#17328483991432266-418: A significant effect on efficiency and durability. A study found that a membrane created via co-axial electrospinning of PVDF - HFP and silica aerogel was able to filter 99.99% of salt after continuous 30-day usage. The leading process for desalination in terms of installed capacity and yearly growth is reverse osmosis (RO). The RO membrane processes use semipermeable membranes and applied pressure (on
2369-457: A substance. One example is soil desalination . This is important for agriculture. It is possible to desalinate saltwater, especially sea water , to produce water for human consumption or irrigation. The by-product of the desalination process is brine . Many seagoing ships and submarines use desalination. Modern interest in desalination mostly focuses on cost-effective provision of fresh water for human use. Along with recycled wastewater , it
2472-492: A vacuum. Under vacuum conditions the ice, desalinated, is melted and diverted for collection and the salt is collected. Electrodialysis uses electric potential to move the salts through pairs of charged membranes, which trap salt in alternating channels. Several variances of electrodialysis exist such as conventional electrodialysis , electrodialysis reversal . Electrodialysis can simultaneously remove salt and carbonic acid from seawater. Preliminary estimates suggest that
2575-482: A vertical tube seawater distilling unit that, thanks to its simplicity of design and ease of construction, gained popularity for shipboard use. Land-based units did not significantly appear until the latter half of the nineteenth century. In the 1860s, the US Army purchased three Normandy evaporators, each rated at 7000 gallons/day and installed them on the islands of Key West and Dry Tortugas . Another land-based plant
2678-512: Is CETO , a wave power technology that desalinates seawater using submerged buoys. Wave-powered desalination plants began operating on Garden Island in Western Australia in 2013 and in Perth in 2015. Membrane distillation uses a temperature difference across a membrane to evaporate vapor from a brine solution and condense pure water on the colder side. The design of the membrane can have
2781-403: Is distillation (i.e., boiling and re- condensation of seawater to leave salt and impurities behind). There are currently two technologies with a large majority of the world's desalination capacity: multi-stage flash distillation and reverse osmosis . Solar distillation mimics the natural water cycle, in which the sun heats sea water enough for evaporation to occur. After evaporation,
2884-500: Is a stub . You can help Misplaced Pages by expanding it . Nuclear reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction . Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion . When a fissile nucleus like uranium-235 or plutonium-239 absorbs a neutron , it splits into lighter nuclei, releasing energy, gamma radiation , and free neutrons, which can induce further fission in
2987-451: Is an artificial process by which saline water (generally sea water ) is converted to fresh water. The most common desalination processes are distillation and reverse osmosis . There are several methods. Each has advantages and disadvantages but all are useful. The methods can be divided into membrane-based (e.g., reverse osmosis ) and thermal-based (e.g., multistage flash distillation ) methods. The traditional process of desalination
3090-548: Is an osmotic pressure gradient, such as a "draw" solution of high concentration. Freeze–thaw desalination (or freezing desalination) uses freezing to remove fresh water from salt water. Salt water is sprayed during freezing conditions into a pad where an ice-pile builds up. When seasonal conditions warm, naturally desalinated melt water is recovered. This technique relies on extended periods of natural sub-freezing conditions. A different freeze–thaw method, not weather dependent and invented by Alexander Zarchin , freezes seawater in
3193-418: Is currently expensive compared to most alternative sources of water, and only a very small fraction of total human use is satisfied by desalination. It is usually only economically practical for high-valued uses (such as household and industrial uses) in arid areas. However, there is growth in desalination for agricultural use and highly populated areas such as Singapore or California. The most extensive use
D1G reactor - Misplaced Pages Continue
3296-425: Is expected that costs will continue to decrease with technology improvements that include, but are not limited to, improved efficiency, reduction in plant footprint, improvements to plant operation and optimization, more effective feed pretreatment, and lower cost energy sources. Reverse osmosis uses a thin-film composite membrane, which comprises an ultra-thin, aromatic polyamide thin-film. This polyamide film gives
3399-498: Is in the Persian Gulf . While noting costs are falling, and generally positive about the technology for affluent areas in proximity to oceans, a 2005 study argued, "Desalinated water may be a solution for some water-stress regions, but not for places that are poor, deep in the interior of a continent, or at high elevation. Unfortunately, that includes some of the places with the biggest water problems.", and, "Indeed, one needs to lift
3502-413: Is inserted deeper into the reactor, it absorbs more neutrons than the material it displaces – often the moderator. This action results in fewer neutrons available to cause fission and reduces the reactor's power output. Conversely, extracting the control rod will result in an increase in the rate of fission events and an increase in power. The physics of radioactive decay also affects neutron populations in
3605-428: Is known as a nuclear chain reaction . To control such a nuclear chain reaction, control rods containing neutron poisons and neutron moderators are able to change the portion of neutrons that will go on to cause more fission. Nuclear reactors generally have automatic and manual systems to shut the fission reaction down if monitoring or instrumentation detects unsafe conditions. The reactor core generates heat in
3708-405: Is mined, processed, enriched, used, possibly reprocessed and disposed of is known as the nuclear fuel cycle . Under 1% of the uranium found in nature is the easily fissionable U-235 isotope and as a result most reactor designs require enriched fuel. Enrichment involves increasing the percentage of U-235 and is usually done by means of gaseous diffusion or gas centrifuge . The enriched result
3811-407: Is more cost effective if kept at a small scale. Wave powered desalination systems generally convert mechanical wave motion directly to hydraulic power for reverse osmosis. Such systems aim to maximize efficiency and reduce costs by avoiding conversion to electricity, minimizing excess pressurization above the osmotic pressure, and innovating on hydraulic and wave power components. One such example
3914-493: Is most suitable for large scale desert greening as it has a km footprint for the water distillation and the same for landscape transformation in desert greening, respectively the regeneration of natural fresh water cycles. In vacuum distillation atmospheric pressure is reduced, thus lowering the temperature required to evaporate the water. Liquids boil when the vapor pressure equals the ambient pressure and vapor pressure increases with temperature. Effectively, liquids boil at
4017-417: Is one of the few water resources independent of rainfall. Due to its energy consumption, desalinating sea water is generally more costly than fresh water from surface water or groundwater , water recycling and water conservation ; however, these alternatives are not always available and depletion of reserves is a critical problem worldwide. Desalination processes are using either thermal methods (in
4120-401: Is produced. Fission also produces iodine-135 , which in turn decays (with a half-life of 6.57 hours) to new xenon-135. When the reactor is shut down, iodine-135 continues to decay to xenon-135, making restarting the reactor more difficult for a day or two, as the xenon-135 decays into cesium-135, which is not nearly as poisonous as xenon-135, with a half-life of 9.2 hours. This temporary state is
4223-448: Is reaching or crossing their design lifetimes of 30 or 40 years. In 2014, Greenpeace warned that the lifetime extension of ageing nuclear power plants amounts to entering a new era of risk. It estimated the current European nuclear liability coverage in average to be too low by a factor of between 100 and 1,000 to cover the likely costs, while at the same time, the likelihood of a serious accident happening in Europe continues to increase as
D1G reactor - Misplaced Pages Continue
4326-416: Is required to determine exactly when a reactor reaches the critical point. Keeping the reactor in the zone of chain reactivity where delayed neutrons are necessary to achieve a critical mass state allows mechanical devices or human operators to control a chain reaction in "real time"; otherwise the time between achievement of criticality and nuclear meltdown as a result of an exponential power surge from
4429-449: Is the most thermodynamically efficient among methods powered by heat, a few limitations exist such as a max temperature and max number of effects. Vapor-compression evaporation involves using either a mechanical compressor or a jet stream to compress the vapor present above the liquid. The compressed vapor is then used to provide the heat needed for the evaporation of the rest of the sea water. Since this system only requires power, it
4532-413: Is then converted into uranium dioxide powder, which is pressed and fired into pellet form. These pellets are stacked into tubes which are then sealed and called fuel rods . Many of these fuel rods are used in each nuclear reactor. Desalination Desalination is a process that removes mineral components from saline water . More generally, desalination is the removal of salts and minerals from
4635-484: The Manhattan Project . Eventually, the first artificial nuclear reactor, Chicago Pile-1 , was constructed at the University of Chicago , by a team led by Italian physicist Enrico Fermi, in late 1942. By this time, the program had been pressured for a year by U.S. entry into the war. The Chicago Pile achieved criticality on 2 December 1942 at 3:25 PM. The reactor support structure was made of wood, which supported
4738-730: The Middle Ages , but desalination became feasible on a large scale only in the modern era. A good example of this experimentation comes from Leonardo da Vinci (Florence, 1452), who realized that distilled water could be made cheaply in large quantities by adapting a still to a cookstove. During the Middle Ages elsewhere in Central Europe, work continued on distillation refinements, although not necessarily directed towards desalination. The first major land-based desalination plant may have been installed under emergency conditions on an island off
4841-514: The PWR , BWR and PHWR designs above, and some are more radical departures. The former include the advanced boiling water reactor (ABWR), two of which are now operating with others under construction, and the planned passively safe Economic Simplified Boiling Water Reactor (ESBWR) and AP1000 units (see Nuclear Power 2010 Program ). Rolls-Royce aims to sell nuclear reactors for the production of synfuel for aircraft. Generation IV reactors are
4944-656: The South Seas , reported that he had been able to supply his men with fresh water by means of shipboard distillation. Additionally, during the early 1600s, several prominent figures of the era such as Francis Bacon and Walter Raleigh published reports on desalination. These reports and others, set the climate for the first patent dispute concerning desalination apparatus. The two first patents regarding water desalination were approved in 1675 and 1683 (patents No. 184 and No. 226, published by William Walcot and Robert Fitzgerald (and others), respectively). Nevertheless, neither of
5047-515: The U.S. Atomic Energy Commission produced 0.8 kW in a test on 20 December 1951 and 100 kW (electrical) the following day, having a design output of 200 kW (electrical). Besides the military uses of nuclear reactors, there were political reasons to pursue civilian use of atomic energy. U.S. President Dwight Eisenhower made his famous Atoms for Peace speech to the UN General Assembly on 8 December 1953. This diplomacy led to
5150-477: The coolant also acts as a neutron moderator . A moderator increases the power of the reactor by causing the fast neutrons that are released from fission to lose energy and become thermal neutrons. Thermal neutrons are more likely than fast neutrons to cause fission. If the coolant is a moderator, then temperature changes can affect the density of the coolant/moderator and therefore change power output. A higher temperature coolant would be less dense, and therefore
5253-496: The dome designed to contain a liquid sodium explosion. In January 2022, a radioactive tank that was used to support the D1G reactor was transported from West Milton, New York to Wampum, Pennsylvania for disassembly. The load was 213 feet long and weighed 294 tons. This article about nuclear power and nuclear reactors for power generation is a stub . You can help Misplaced Pages by expanding it . This United States Navy article
SECTION 50
#17328483991435356-402: The "iodine pit." If the reactor has sufficient extra reactivity capacity, it can be restarted. As the extra xenon-135 is transmuted to xenon-136, which is much less a neutron poison, within a few hours the reactor experiences a "xenon burnoff (power) transient". Control rods must be further inserted to replace the neutron absorption of the lost xenon-135. Failure to properly follow such a procedure
5459-457: The 1500s, and formulated practical advice that was publicized to all U.S. ships on the reverse side of sailing clearance permits. Beginning about 1800, things started changing as a consequence of the appearance of the steam engine and the so-called age of steam . Knowledge of the thermodynamics of steam processes and the need for a pure water source for its use in boilers generated a positive effect regarding distilling systems. Additionally,
5562-566: The 1986 Chernobyl disaster and 2011 Fukushima disaster . As of 2022 , the International Atomic Energy Agency reported there are 422 nuclear power reactors and 223 nuclear research reactors in operation around the world. The US Department of Energy classes reactors into generations, with the majority of the global fleet being Generation II reactors constructed from the 1960s to 1990s, and Generation IV reactors currently in development. Reactors can also be grouped by
5665-476: The RO membranes are destroyed. To mitigate damage, various pretreatment stages are introduced. Anti-scaling inhibitors include acids and other agents such as the organic polymers polyacrylamide and polymaleic acid , phosphonates and polyphosphates . Inhibitors for fouling are biocides (as oxidants against bacteria and viruses), such as chlorine, ozone, sodium or calcium hypochlorite. At regular intervals, depending on
5768-708: The U.S. military sought other uses for nuclear reactor technology. Research by the Army led to the power stations for Camp Century, Greenland and McMurdo Station, Antarctica Army Nuclear Power Program . The Air Force Nuclear Bomber project resulted in the Molten-Salt Reactor Experiment . The U.S. Navy succeeded when they steamed the USS Nautilus (SSN-571) on nuclear power 17 January 1955. The first commercial nuclear power station, Calder Hall in Sellafield , England
5871-645: The UAE; and the biggest plant with a volume of 1,401,000 m3/d is in Saudi Arabia (Ras Al Khair). As of 2021 22,000 plants were in operation In 2024 the Catalan government installed a floating offshore plant near the port of Barcelona and purchased 12 mobile desalination units for the northern region of the Costa Brava to combat the severe drought. In 2012, cost averaged $ 0.75 per cubic meter. By 2022, that had declined (before inflation) to $ 0.41. Desalinated supplies are growing at
5974-528: The United States does not engage in or encourage reprocessing. Reactors are also used in nuclear propulsion of vehicles. Nuclear marine propulsion of ships and submarines is largely restricted to naval use. Reactors have also been tested for nuclear aircraft propulsion and spacecraft propulsion . Reactor safety is maintained through various systems that control the rate of fission. The insertion of control rods, which absorb neutrons, can rapidly decrease
6077-565: The area was contaminated, like Fukushima, Three Mile Island, Sellafield, and Chernobyl. The British branch of the French concern EDF Energy , for example, extended the operating lives of its Advanced Gas-cooled Reactors (AGR) with only between 3 and 10 years. All seven AGR plants were expected to be shut down in 2022 and in decommissioning by 2028. Hinkley Point B was extended from 40 to 46 years, and closed. The same happened with Hunterston B , also after 46 years. An increasing number of reactors
6180-770: The beginning of his quest to produce the Einstein-Szilárd letter to alert the U.S. government. Shortly after, Nazi Germany invaded Poland in 1939, starting World War II in Europe. The U.S. was not yet officially at war, but in October, when the Einstein-Szilárd letter was delivered to him, Roosevelt commented that the purpose of doing the research was to make sure "the Nazis don't blow us up." The U.S. nuclear project followed, although with some delay as there remained skepticism (some of it from Enrico Fermi ) and also little action from
6283-473: The case of distillation ) or membrane-based methods (e.g. in the case of reverse osmosis ). An estimate in 2018 found that "18,426 desalination plants are in operation in over 150 countries. They produce 87 million cubic meters of clean water each day and supply over 300 million people." The energy intensity has improved: It is now about 3 kWh/m (in 2018), down by a factor of 10 from 20–30 kWh/m in 1970. Nevertheless, desalination represented about 25% of
SECTION 60
#17328483991436386-414: The channel, the researchers were able to achieve NaCL concentration drop of 25000 ppm with a recovery rate of 10% of the original water volume. The desalination process's energy consumption depends on the water's salinity. Brackish water desalination requires less energy than seawater desalination. The energy intensity of seawater desalination has improved: It is now about 3 kWh/m (in 2018), down by
6489-458: The choices of coolant and moderator. Almost 90% of global nuclear energy comes from pressurized water reactors and boiling water reactors , which use water as a coolant and moderator. Other designs include heavy water reactors , gas-cooled reactors , and fast breeder reactors , variously optimizing efficiency, safety, and fuel type , enrichment , and burnup . Small modular reactors are also an area of current development. These reactors play
6592-642: The coast of Tunisia in 1560. It is believed that a garrison of 700 Spanish soldiers was besieged by the Turkish army and that, during the siege, the captain in charge fabricated a still capable of producing 40 barrels of fresh water per day, though details of the device have not been reported. Before the Industrial Revolution , desalination was primarily of concern to oceangoing ships, which otherwise needed to keep on board supplies of fresh water. Sir Richard Hawkins (1562–1622), who made extensive travels in
6695-467: The complexities of handling actinides , but significant scientific and technical obstacles remain. Despite research having started in the 1950s, no commercial fusion reactor is expected before 2050. The ITER project is currently leading the effort to harness fusion power. Thermal reactors generally depend on refined and enriched uranium . Some nuclear reactors can operate with a mixture of plutonium and uranium (see MOX ). The process by which uranium ore
6798-421: The condensation of the water vapor from the previous step. Multiple-effect distillation (MED) works through a series of steps called "effects". Incoming water is sprayed onto pipes which are then heated to generate steam. The steam is then used to heat the next batch of incoming sea water. To increase efficiency, the steam used to heat the sea water can be taken from nearby power plants. Although this method
6901-617: The construction of over 200 electrodialysis and distillation plants globally, reverse osmosis (RO) research, and international cooperation (for example, the First International Water Desalination Symposium and Exposition in 1965). The Office of Saline Water merged into the Office of Water Resources Research in 1974. The first industrial desalination plant in the United States opened in Freeport, Texas in 1961 after
7004-444: The cost of such carbon removal can be paid for in large part if not entirely from the sale of the desalinated water produced as a byproduct. Microbial desalination cells are biological electrochemical systems that implements the use of electro-active bacteria to power desalination of water in situ , resourcing the natural anode and cathode gradient of the electro-active bacteria and thus creating an internal supercapacitor . In
7107-660: The dissemination of reactor technology to U.S. institutions and worldwide. The first nuclear power plant built for civil purposes was the AM-1 Obninsk Nuclear Power Plant , launched on 27 June 1954 in the Soviet Union . It produced around 5 MW (electrical). It was built after the F-1 (nuclear reactor) which was the first reactor to go critical in Europe, and was also built by the Soviet Union. After World War II,
7210-407: The energy consumed by the water sector in 2016. Ancient Greek philosopher Aristotle observed in his work Meteorology that "salt water, when it turns into vapour, becomes sweet and the vapour does not form salt water again when it condenses", and that a fine wax vessel would hold potable water after being submerged long enough in seawater, having acted as a membrane to filter the salt. At
7313-485: The energy of the neutrons that sustain the fission chain reaction : In principle, fusion power could be produced by nuclear fusion of elements such as the deuterium isotope of hydrogen . While an ongoing rich research topic since at least the 1940s, no self-sustaining fusion reactor for any purpose has ever been built. Used by thermal reactors: In 2003, the French Commissariat à l'Énergie Atomique (CEA)
7416-638: The first reactor dedicated to peaceful use; in Russia, in 1954, the first small nuclear power reactor APS-1 OBNINSK reached criticality. Other countries followed suit. Heat from nuclear fission is passed to a working fluid coolant (water or gas), which in turn runs through turbines . In commercial reactors, turbines drive electrical generator shafts. The heat can also be used for district heating , and industrial applications including desalination and hydrogen production . Some reactors are used to produce isotopes for medical and industrial use. Reactors pose
7519-407: The fission process generates heat, some of which can be converted into usable energy. A common method of harnessing this thermal energy is to use it to boil water to produce pressurized steam which will then drive a steam turbine that turns an alternator and generates electricity. Modern nuclear power plants are typically designed for a lifetime of 60 years, while older reactors were built with
7622-529: The form of boric acid ) into the reactor to shut the fission reaction down if unsafe conditions are detected or anticipated. Most types of reactors are sensitive to a process variously known as xenon poisoning, or the iodine pit . The common fission product Xenon-135 produced in the fission process acts as a neutron poison that absorbs neutrons and therefore tends to shut the reactor down. Xenon-135 accumulation can be controlled by keeping power levels high enough to destroy it by neutron absorption as fast as it
7725-424: The fuel rods. This allows the reactor to be constructed with an excess of fissionable material, which is nevertheless made relatively safe early in the reactor's fuel burn cycle by the presence of the neutron-absorbing material which is later replaced by normally produced long-lived neutron poisons (far longer-lived than xenon-135) which gradually accumulate over the fuel load's operating life. The energy released in
7828-447: The idea of nuclear fission as a neutron source, since that process was not yet discovered. Szilárd's ideas for nuclear reactors using neutron-mediated nuclear chain reactions in light elements proved unworkable. Inspiration for a new type of reactor using uranium came from the discovery by Otto Hahn , Lise Meitner , and Fritz Strassmann in 1938 that bombardment of uranium with neutrons (provided by an alpha-on-beryllium fusion reaction,
7931-507: The membrane contamination; fluctuating seawater conditions; or when prompted by monitoring processes, the membranes need to be cleaned, known as emergency or shock-flushing. Flushing is done with inhibitors in a fresh water solution and the system must go offline. This procedure is environmentally risky, since contaminated water is diverted into the ocean without treatment. Sensitive marine habitats can be irreversibly damaged. Off-grid solar-powered desalination units use solar energy to fill
8034-438: The membrane feed side) to preferentially induce water permeation through the membrane while rejecting salts. Reverse osmosis plant membrane systems typically use less energy than thermal desalination processes. Energy cost in desalination processes varies considerably depending on water salinity, plant size and process type. At present the cost of seawater desalination, for example, is higher than traditional water sources, but it
8137-674: The membrane its transport properties, whereas the remainder of the thin-film composite membrane provides mechanical support. The polyamide film is a dense, void-free polymer with a high surface area, allowing for its high water permeability. A recent study has found that the water permeability is primarily governed by the internal nanoscale mass distribution of the polyamide active layer. The reverse osmosis process requires maintenance. Various factors interfere with efficiency: ionic contamination (calcium, magnesium etc.); dissolved organic carbon (DOC); bacteria; viruses; colloids and insoluble particulates; biofouling and scaling . In extreme cases,
8240-549: The newest reactors has an energy density 120,000 times higher than coal. Nuclear reactors have their origins in the World War II Allied Manhattan Project . The world's first artificial nuclear reactor, Chicago Pile-1, achieved criticality on 2 December 1942. Early reactor designs sought to produce weapons-grade plutonium for fission bombs , later incorporating grid electricity production in addition. In 1957, Shippingport Atomic Power Station became
8343-449: The normal nuclear chain reaction, would be too short to allow for intervention. This last stage, where delayed neutrons are no longer required to maintain criticality, is known as the prompt critical point. There is a scale for describing criticality in numerical form, in which bare criticality is known as zero dollars and the prompt critical point is one dollar , and other points in the process interpolated in cents. In some reactors,
8446-581: The opportunity for the nuclear chain reaction that Szilárd had envisioned six years previously. On 2 August 1939, Albert Einstein signed a letter to President Franklin D. Roosevelt (written by Szilárd) suggesting that the discovery of uranium's fission could lead to the development of "extremely powerful bombs of a new type", giving impetus to the study of reactors and fission. Szilárd and Einstein knew each other well and had worked together years previously, but Einstein had never thought about this possibility for nuclear energy until Szilard reported it to him, at
8549-406: The physics of radioactive decay and are simply accounted for during the reactor's operation, while others are mechanisms engineered into the reactor design for a distinct purpose. The fastest method for adjusting levels of fission-inducing neutrons in a reactor is via movement of the control rods . Control rods are made of so-called neutron poisons and therefore absorb neutrons. When a control rod
8652-460: The power plant is limited by the life of components that cannot be replaced when aged by wear and neutron embrittlement , such as the reactor pressure vessel. At the end of their planned life span, plants may get an extension of the operating license for some 20 years and in the US even a "subsequent license renewal" (SLR) for an additional 20 years. Even when a license is extended, it does not guarantee
8755-563: The reactor fleet grows older. The neutron was discovered in 1932 by British physicist James Chadwick . The concept of a nuclear chain reaction brought about by nuclear reactions mediated by neutrons was first realized shortly thereafter, by Hungarian scientist Leó Szilárd , in 1933. He filed a patent for his idea of a simple reactor the following year while working at the Admiralty in London, England. However, Szilárd's idea did not incorporate
8858-416: The reactor will continue to operate, particularly in the face of safety concerns or incident. Many reactors are closed long before their license or design life expired and are decommissioned . The costs for replacements or improvements required for continued safe operation may be so high that they are not cost-effective. Or they may be shut down due to technical failure. Other ones have been shut down because
8961-437: The reactor's output, while other systems automatically shut down the reactor in the event of unsafe conditions. The buildup of neutron-absorbing fission products like xenon-135 can influence reactor behavior, requiring careful management to prevent issues such as the iodine pit , which can complicate reactor restarts. There have been two reactor accidents classed as an International Nuclear Event Scale Level 7 "major accident":
9064-882: The same time the desalination of seawater was recorded in China. Both the Classic of Mountains and Water Seas in the Period of the Warring States and the Theory of the Same Year in the Eastern Han Dynasty mentioned that people found that the bamboo mats used for steaming rice would form a thin outer layer after long use. The as-formed thin film had adsorption and ion exchange functions, which could adsorb salt. Numerous examples of experimentation in desalination appeared throughout Antiquity and
9167-407: The sea and somewhat high, such as Riyadh and Harare . By contrast in other locations transport costs are much less, such as Beijing, Bangkok , Zaragoza , Phoenix , and, of course, coastal cities like Tripoli . After desalination at Jubail , Saudi Arabia, water is pumped 320 km inland to Riyadh . For coastal cities, desalination is increasingly viewed as a competitive choice. In 2023, Israel
9270-637: The small number of officials in the government who were initially charged with moving the project forward. The following year, the U.S. Government received the Frisch–Peierls memorandum from the UK, which stated that the amount of uranium needed for a chain reaction was far lower than had previously been thought. The memorandum was a product of the MAUD Committee , which was working on the UK atomic bomb project, known as Tube Alloys , later to be subsumed within
9373-417: The spread of European colonialism induced a need for freshwater in remote parts of the world, thus creating the appropriate climate for water desalination. In parallel with the development and improvement of systems using steam ( multiple-effect evaporators ), these type of devices quickly demonstrated their desalination potential. In 1852, Alphonse René le Mire de Normandy was issued a British patent for
9476-440: The two inventions entered service as a consequence of scale-up difficulties. No significant improvements to the basic seawater distillation process were made during the 150 years from the mid-1600s until 1800. When the frigate Protector was sold to Denmark in the 1780s (as the ship Hussaren ) its still was studied and recorded in great detail. In the United States, Thomas Jefferson catalogued heat-based methods going back to
9579-428: The water by 2000 m, or transport it over more than 1600 km to get transport costs equal to the desalination costs." Thus, it may be more economical to transport fresh water from somewhere else than to desalinate it. In places far from the sea, like New Delhi, or in high places, like Mexico City , transport costs could match desalination costs. Desalinated water is also expensive in places that are both somewhat far from
9682-424: The water for the steam turbines is boiled directly by the reactor core ; for example the boiling water reactor . The rate of fission reactions within a reactor core can be adjusted by controlling the quantity of neutrons that are able to induce further fission events. Nuclear reactors typically employ several methods of neutron control to adjust the reactor's power output. Some of these methods arise naturally from
9785-425: The water vapor is condensed onto a cool surface. There are two types of solar desalination. The first type uses photovoltaic cells to convert solar energy to electrical energy to power desalination. The second type converts solar energy to heat, and is known as solar thermal powered desalination. Water can evaporate through several other physical effects besides solar irradiation . These effects have been included in
9888-476: Was a key step in the Chernobyl disaster . Reactors used in nuclear marine propulsion (especially nuclear submarines ) often cannot be run at continuous power around the clock in the same way that land-based power reactors are normally run, and in addition often need to have a very long core life without refueling . For this reason many designs use highly enriched uranium but incorporate burnable neutron poison in
9991-544: Was created in the United States Department of the Interior in 1955 in accordance with the Saline Water Conversion Act of 1952. This act was motivated by a water shortage in California and inland western United States. The Department of the Interior allocated resources including research grants, expert personnel, patent data, and land for experiments to further advancements. The results of these efforts included
10094-585: Was installed at Suakin during the 1880s that provided freshwater to the British troops there. It consisted of six-effect distillers with a capacity of 350 tons/day. After World War II, many technologies were developed or improved such as Multi Effect Flash desalination (MEF) and Multi Stage Flash desalination (MSF). Another notable technology is freeze-thaw desalination. Freeze-thaw desalination, (cryo-desalination or FD), excludes dissolved minerals from saline water through crystallization. The Office of Saline Water
10197-781: Was officially started by the Generation ;IV International Forum (GIF) based on eight technology goals. The primary goals being to improve nuclear safety, improve proliferation resistance, minimize waste and natural resource utilization, and to decrease the cost to build and run such plants. Generation V reactors are designs which are theoretically possible, but which are not being actively considered or researched at present. Though some generation V reactors could potentially be built with current or near term technology, they trigger little interest for reasons of economics, practicality, or safety. Controlled nuclear fusion could in principle be used in fusion power plants to produce power without
10300-463: Was opened in 1956 with an initial capacity of 50 MW (later 200 MW). The first portable nuclear reactor "Alco PM-2A" was used to generate electrical power (2 MW) for Camp Century from 1960 to 1963. All commercial power reactors are based on nuclear fission . They generally use uranium and its product plutonium as nuclear fuel , though a thorium fuel cycle is also possible. Fission reactors can be divided roughly into two classes, depending on
10403-503: Was shut down in March of that year. It was later defuelled, with the pressure vessel eventually removed in 2002. The containment structure — which housed both the primary (nuclear reactor) and secondary (steam plant) systems — is referred to as the "DIG-ball" due to its unique shape: a Horton sphere . The sphere was originally constructed by Chicago Bridge and Iron Works to house the liquid metal cooled reactor of USS Seawolf , with
10506-553: Was the first to refer to "Gen II" types in Nucleonics Week . The first mention of "Gen III" was in 2000, in conjunction with the launch of the Generation IV International Forum (GIF) plans. "Gen IV" was named in 2000, by the United States Department of Energy (DOE), for developing new plant types. More than a dozen advanced reactor designs are in various stages of development. Some are evolutionary from
10609-505: Was using desalination to replenish the Sea of Galilee 's water supply. Not everyone is convinced that desalination is or will be economically viable or environmentally sustainable for the foreseeable future. Debbie Cook wrote in 2011 that desalination plants can be energy intensive and costly. Therefore, water-stressed regions might do better to focus on conservation or other water supply solutions than invest in desalination plants. Desalination
#142857