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106-638: Emu Field (also Emu Junction or simply Emu ) is the site of Operation Totem , a pair of nuclear tests conducted by the British Government in South Australia during October 1953. The site was surveyed by Len Beadell in 1952. A village and airstrip were constructed for the subsequent testing program. The site was supported from the RAAF Woomera Range Complex . Two British nuclear weapon tests were conducted at

212-479: 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,

318-682: A nuclear weapons project, code-named Tube Alloys , which the 1943 Quebec Agreement merged with the American Manhattan Project to create a combined American, British, and Canadian project. The British government expected that the United States would continue to share nuclear technology, which it regarded as a joint discovery, after the war, but the United States Atomic Energy Act of 1946 (McMahon Act) ended technical co-operation. Fearing

424-558: 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

530-696: A British nuclear physicist who had worked on the Manhattan Project but was now living in Australia, to be observers. In addition, 45 Australians would participate as part of the test team, including some Royal Australian Navy personnel who had been involved in Operation Hurricane. Ten of them would be part of the Radiation Hazards Group (RH5). An important concern was the welfare of the local Aboriginal people,

636-517: A Totem Panel chaired by J. E. S. Stevens , the head of the Department of Supply, was created to coordinate the Australian contribution. With defence money short and Britain paying for the tests, it was important that expenditure was correctly recorded and charged. The total cost of the trial was estimated at £799,700. Unlike Hurricane, it was decided that it would be best if a single service

742-441: 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

848-445: 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

954-442: 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

1060-424: 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

1166-570: 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

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1272-465: 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

1378-773: 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

1484-407: 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

1590-471: 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

1696-660: A representative of the Australian Security Intelligence Organisation (ASIO), visited the UK in February 1953 to discuss the arrangements for Totem. There was a week of discussions, culminating in the Australians attending the second meeting of Totex. Lucas informed the people at Fort Halstead , where Penney's High Explosive Research team was based, that their plan for a temporary village of trailers had to be discarded. Lucas told them that

1802-659: A resurgence of United States isolationism , and Britain losing its great power status, the British government restarted its own development effort, which was given the cover name " High Explosive Research ". The first British atomic bomb was tested in Operation Hurricane at the Montebello Islands in Western Australia on 3 October 1952. The main purpose of the trial was to determine

1908-430: 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

2014-529: 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

2120-542: A smaller fissile charge, and one of a new experimental type. The Prime Minister of the United Kingdom , Winston Churchill , then sought permission from Menzies, who was in London at the time. Churchill's scientific adviser, Lord Cherwell , handed Menzies an aide-mémoire on 13 December. Two days later the acting Prime Minister, Arthur Fadden , signalled his approval for the tests from Australia. The test series

2226-651: A war zone. After the Totem 1 test, a black mist rolled across the landscape at the Wallatina and Welbourn Hill stations in the Granite Downs 175 kilometres (109 mi) from the test site, and led to unacceptably high levels of radioactive contamination of these locations. There is controversy surrounding injuries received by Aboriginal people from fallout, and in particular from this mist. Approximately 45 Yankuntjatjarra people were reported to have been caught in

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2332-413: 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

2438-428: 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

2544-405: 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

2650-401: 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

2756-448: 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

2862-416: 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

2968-522: The Bikini Atoll nuclear experiments , was present at the first Totem test and subsequently became a pacifist and a founding member of the Campaign for Nuclear Disarmament . Two more Kitten tests were carried out on 14 and 17 October. The Totem 2 test, another tower test, was scheduled for 24 October, but once again the weather intervened, and it was postponed to 27 October. Penney forecast that

3074-806: The Foreign Office that Menzies had agreed in principle to Penney's reconnaissance of the Emu Field site. Penney flew in to the Dingo Claypan in a Royal Air Force (RAF) Percival Prince . His party included Pritchard, Butement, Martin, Ben Gates (the range controller), Ivor Bowen from the UK Ministry of Supply staff in Melbourne and Omond Solandt from the Canadian Defence Research Board . The party inspected

3180-713: The Great Victoria Desert 480 kilometres (300 mi) north west of Woomera, South Australia . A natural claypan known as the Dingo Claypan provided a ready-made airstrip. In August, Sir William Penney , the Chief Superintendent Armament Research (CSAR) at the British Ministry of Supply , and the head of the British atomic weapon development effort, notified W. A. S. Butement , the Chief Scientist at

3286-490: 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

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3392-517: 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

3498-567: The Pitjantjatjara and Yankuntjatjarra , who inhabited the area. They lived through hunting and gathering activities, and moved over long distances between permanent and semi-permanent locations, generally in groups of about 25 or so, coming together for special occasions. The construction of the Trans-Australian Railway in 1917 had disrupted their traditional patterns of movement. Walter MacDougall had been appointed

3604-709: The Prime Minister of Australia , Robert Menzies , at a meeting on 4 September. Other matters discussed included the attendance of Butement and Leslie Martin , the Australian Defence Scientific Adviser, as Australian observers at the Hurricane test, the creation of the Australian Atomic Energy Commission , and the supply of Australian uranium to the UK. Cockcroft reported to Sir Roger Makins at

3710-1090: The Royal Australian Survey Corps . Civilians came from the LRWEs at Salisbury and Woomera. The RAAF also provided ten Avro Lincoln bombers based at RAAF Woomera and RAAF Richmond for air sampling, and two Dakota transports based at Woomera for ground contamination surveys. The RAF provided a lone Canberra bomber for cloud sampling. The United States Air Force (USAF) had two Boeing B-29 Superfortress bombers and two Douglas C-54 Skymaster transport aircraft based at RAAF Richmond for radioactive cloud sampling. A five-man Australian mission consisting of Lucas, Gates, Group Captain Alfred George Pither (the LRWE Range Superintendent), Frank O'Grady (the Superintendent of Engineering at LRWE Salisbury), and

3816-524: 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

3922-477: 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

4028-404: The radioactive cloud from the first detonation did not disperse as expected, and travelled north-east over the Australian continent. The site at Emu Field was unsafe for further testing due to contamination by nuclear radiation , and the search for another location led to the survey of Maralinga , where a further series of atomic tests was conducted in 1956 . There are now stone monuments at

4134-402: 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

4240-580: 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

4346-644: The Aboriginal people reluctant to reveal important details such as the location of water holes and sacred sites , but they did inform him that the Dingo Claypan area, which was in Yankuntjatjarra territory, had no particular importance or significance. MacDougall paid personal visits to pastoral stations in August 1953, warning the station managers, and requesting that the warnings be passed on to local Aboriginal people. Warning notices were posted around

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4452-573: The Australian Department of Supply , of his intention to visit the site before the Hurricane test. Butement warned Penney that it was very remote, and that Beadell and his companions might well have been the first non- Aboriginal people to see the area. Sir John Cockcroft , the director of the Atomic Weapons Research Establishment , personally lodged a formal request for a feasibility study with

4558-479: The Australian government by Australian or British scientists. The tests spread toxic beryllium and highly radioactive polonium around the test sites. Care was taken not to contaminate the main test site, and the areas were secured until the polonium decayed to safe levels. A full-scale rehearsal was held on 1 October, and the countdown commenced on 7 October, but was immediately cancelled due to bad weather. Rain set in on 8 October. Hopes for 10 October soon faded, and

4664-547: The British team had prepared. They were not provided details about the bomb's design, but assurances were given that the Totem devices contained much less fissile material than the Hurricane device. Martin was particularly concerned that balloon flights had indicated that in October there were east and north east winds with speeds of up to 190 kilometres per hour (100 kn) between 9,100 and 12,200 metres (30,000 and 40,000 ft). Penney reassured Martin and Titterton that while

4770-415: The Emu Field site was on the Australian mainland, the Australian government required much more information than they had for the Hurricane test about nuclear fallout and radioactive contamination . The aide-mémoire that Lord Cherwell had given Menzies offered to provide information to Martin and Titterton on the possible radioactive hazards. Arrangements were made for them to see the full hazards report that

4876-786: The Native Patrol Officer at Woomera on 4 November 1947, with responsibility for ensuring that Aboriginal people were not harmed by the LRWE's rocket testing programme. He was initially assigned to the Department of Works and Housing but was transferred to the Department of Supply in May 1949. As the range of the rockets increased, so too did the range of his patrols, from 576 kilometres (358 mi) in October 1949 to 3,486 kilometres (2,166 mi) in March and April 1952. MacDougall found

4982-499: The Operation Totem tests was £828,000, of which £694,000 was paid by the UK and £134,000 by Australia. The UK share went towards plant, equipment, building materials and air and land transport. The Australian share was mainly spent on pay and allowances for service personnel. With the test series concluded, the Emu Field site was abandoned. Daily RAAF flights flew personnel out. Penney departed on 2 November, and arrived back in

5088-736: 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

5194-530: The UK ten days later. Australian service personnel were flown back to their home states in time for Christmas. All UK staff departed by 17 November, although some remained in Australia at Woomera and Salisbury. The last personnel departed on 29 November, although flights to the claypan to remove equipment continued. Some stores were returned to the UK, while others were stored at Woomera and Salisbury. All that remained were three Commonwealth Peace Officers to ensure that no one entered K Site. For their services, Lucas

5300-472: 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

5406-515: The acceptable limit of the amount of plutonium-240 that could be present in a bomb. The plutonium used in the original Hurricane device was produced in the nuclear reactor at Windscale , but the Windscale Piles did not have the capacity to provide sufficient material for the British government's planned weapons programme, and consequently eight more reactors were planned. These were intended to produce both electricity and plutonium , and

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5512-412: The airstrip and about 13 kilometres (8 mi) north west of the main test site. These tests, which the British called "Kittens", did not produce nuclear explosions, but used conventional explosives, polonium-210 , beryllium and natural uranium to investigate the performance of neutron initiators . They were performed without formal Australian government approval, and without any advice being given to

5618-474: The amount of plutonium-240 which could be present in a bomb. In addition to the two main tests, there was a series of five subcritical tests called "Kittens". These did not produce nuclear explosions, but used conventional explosives, polonium-210 , beryllium and natural uranium to investigate the performance of neutron initiators . During the early part of the Second World War , Britain had

5724-462: The area by helicopter and Land Rover ; the light sandy clay soil was easily traversed by motor vehicles. The drawbacks of the Emu Field site were also discussed. These included the fact that there was no all-weather road from Woomera. In December, Penney secured ministerial permission from the British government for two tests to take place in October 1953: one of the Blue Danube type but with

5830-569: 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

5936-740: 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

6042-458: 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

6148-579: The cloud maintained its form for 24 hours, and produced a tight fallout pattern in the immediate vicinity of the test site the like of which had not been seen before. The five Lincolns assigned to sampling the cloud made 15 traverses in three hours. The filters were found to have radioactivity in excess of the requirements of the radiochemistry team, and were left for twelve hours to cool down. The crews were checked for contamination and, after showering, were found to be clean. The aircraft were parked away from other planes. The hazards team found contamination on

6254-467: 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

6360-566: The conclusion of these tests, the British government formally requested a permanent testing site from the Australian government, which led to the agreement on the use of the Maralinga test site in August 1954. However it was not ready for the next trial, Operation Mosaic , which was held in the Montebello Islands in May 1956. This was a pair of tests as part of the development of thermonuclear weapons . The first trial at Maralinga

6466-457: The crew. After the test, the film badges indicated that a crew would have received enough radiation to have become sick within a few hours and died within a few days. The damage to the tank was much less than expected; it had not caught fire and the engine was still running. It was later driven from the test site under its own power. The tank's light damage was repaired, and it was put back into service. Subsequently, nicknamed The Atomic Tank , it

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6572-411: The design was known as PIPPA, for pressurised pile producing power and plutonium. Although PIPPA produced less plutonium than a Windscale Pile, it also produced electricity which it could put back into the grid, whereas a Windscale Pile consumed GBP £340,000 a year worth of electricity to run its blowers. The electricity produced was more expensive than that of a conventional coal-fired plant, but this

6678-688: 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,

6784-494: 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)

6890-489: The exact location of the test site. The device was detonated from a tower at 07:00 on 14 October local time (21:30 on 13 October UTC ). The yield was predicted to be between 0.25 and 10 kilotonnes of TNT (1.0 and 41.8 TJ), most probably in the 2 and 3 kilotonnes of TNT (8.4 and 12.6 TJ) range. In the event it was higher than forecast; Penney estimated it at 10 kilotonnes of TNT (42 TJ). The cloud rose to 4,600 metres (15,000 ft). The slight wind meant that

6996-642: 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

7102-407: 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

7208-414: The following day was a Sunday, and the Australian government had indicated that it did not want tests to take place on Sundays, so the test was rescheduled for 12 October, then twice postponed to the next day. This time the weather held. VIPs and media representatives were flown in from Adelaide in the early hours of the morning with the aircraft windows covered in canvas screens so they could not identify

7314-529: 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

7420-424: 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

7526-480: The ground-zero points, which can be visited by tourists (with the written approval of the RAAF Woomera Test Range who now control access to the area), though the location is still extremely remote (see Anne Beadell Highway ). Evidence of the explosions may still be seen at ground-zero in the form of vitrified sand and concentric blast rings. A history of the tests at Emu Field by Elizabeth Tynan

7632-447: 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,

7738-476: The leading edges and tailplanes, although it was within acceptable limits. Ground crews were permitted to work on the aircraft, although they were instructed not to eat or smoke while working on the aircraft. A Centurion tank , Registration Number 169041 , was positioned approximately 320 metres (350 yd) from ground zero . Two hours before the test it was left with the hatch closed, engine running and brakes off, and test dummies with film badges representing

7844-438: The mist at Wallatina and fallen ill. The 1985 Royal Commission concluded that "Aboriginal people experienced radioactive fallout from Totem 1 in the form of a black mist or cloud at or near Wallatina. This may have made some people temporarily ill. The Royal Commission does not have sufficient evidence to say whether or not it caused other illnesses or injuries." British journalist James Cameron , who had previously reported on

7950-564: 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

8056-449: 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,

8162-581: 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

8268-401: The perimeter of the test site, and aerial and ground searches, usually within 32 kilometres (20 mi) of the site, were made with increasing frequency as the test firings approached. The 1985 Royal Commission into British nuclear tests in Australia was critical of these efforts, which it deemed inadequate to warn people spread over 10,000 square kilometres (3,900 sq mi). Because

8374-406: 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

8480-463: 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

8586-432: The radioactive cloud might rise above 4,600 metres (15,000 ft), it would not reach 9,100 metres (30,000 ft). On this basis they reported to Menzies that no people would suffer ill-effects from the trials. The first Totem test was preceded by three Kitten tests carried out at the Emu Field site on 26 and 30 September, and 6 October. These were conducted in an area known as K Site, 6.4 kilometres (4 mi) east of

8692-519: 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

8798-416: 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

8904-437: 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":

9010-399: The risk of criticality accident and a fizzle that would reduce the yield . Nuclear testing was required to gauge the effect of an increased proportion of plutonium-240. The Royal Navy was unable to provide the level of support it had for the Operation Hurricane test in the time available, so the Montebello Islands were ruled out. The search for an alternative site on the mainland in

9116-517: The site. Totem I was detonated on 15 October 1953 and Totem II was detonated on 27 October 1953. The devices were both sited on towers and yielded 9 kilotons and 7 kilotons respectively. The site was also used in September–October 1953 for some of the Kitten series of tests, which were conventional (rather than nuclear) explosions used to evaluate neutron initiators . It was later found that

9222-599: 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

9328-553: The test arrived by road, the bulk arriving via the airstrip, which was quickly constructed on the site about 17 kilometres (11 mi) north west of the test field on a dry lake bed. This required a much greater air transport effort from the RAF and RAAF than originally envisaged. The main scientific party arrived on 17 August and the device for the first test arrived on 26 September to be followed three days later by Penney. The British government invited Martin, Butement and Ernest Titterton ,

9434-475: The trailers would not be able to make it over the first sand hill. Instead, Australian Nissen huts would be used for the offices and laboratories, and test personnel would be accommodated in tents. Lucas was able to allay fears about the supply of water, which would not only be required for drinking, but also for decontamination of personnel and equipment, and the processing of the film badges which registered how much radioactivity people had been exposed to. Lucas

9540-726: The vicinity of the Woomera Rocket Range had already begun in June 1952. Surveys of the area were carried out by Len Beadell , the surveyor at the Long Range Weapons Establishment (LRWE). Harry Pritchard, the Chief Superintendent there, loaned a Bristol Sycamore helicopter for the purpose. A site, originally given the codename X200 but later renamed Emu Field, was selected. It was an isolated dry, flat clay and sandstone expanse in

9646-424: 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

9752-480: The wind direction below 3,700 metres (12,000 ft) was an acceptable 10 degrees, at 6,100 metres (20,000 ft) it was 270 degrees. However high winds dispersed the cloud so that it had dissipated to the point where it could not be tracked far. The British scientists believed that sufficient data had been collected from Totem 1, so only two Lincolns and the USAF B-29s were used for Totem 2. The total cost of

9858-469: The yield of Totem 2 would be between 2 and 3 kilotonnes of TNT (8.4 and 12.6 TJ). It was exploded at 07:00 on 27 October local time (21:30 on 26 October UTC). Penney estimated the actual yield at 10 to 18 kilotonnes of TNT (42 to 75 TJ); later measurements showed it to be 8 kilotonnes of TNT (33 TJ). The Totem 2 cloud rose higher than that of Totem 1, to 8,500 metres (28,000 ft) because of condensation of moisture entrained in it, and whilst

9964-481: 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

10070-399: Was able to inform them that adequate supplies of bore water would be available, although a distillation plant would still be required. The UK team also explained that in addition to the two atomic tests, there would be a series of subcritical tests . The isolated location and poor roads meant that only 500 tonnes (500 long tons) of the 3,000 tonnes (3,000 long tons) of equipment needed for

10176-698: Was appointed deputy director and supervisor of construction. The construction force was drawn from the Army, the Royal Australian Air Force (RAAF), and the Departments of Supply and Works. The main units involved were detachments from No. 5 Airfield Construction Squadron RAAF , and the Army's 7th Independent Field Squadron, 17th Construction Squadron , with elements of the Royal Australian Electrical and Mechanical Engineers , Royal Australian Corps of Signals and

10282-472: Was given the codename Totem. A Totem Executive (Totex) chaired by Air Marshal Sir Thomas Elmhirst was formed in the UK to coordinate the tests. The UK government agreed to foot the bill for the tests. Penney was appointed the trial director, with Leonard Tyte as scientific director. Tyte was appointed to the National Coal Board in May 1953, and was replaced by Charles Adams. In Australia,

10388-639: Was held in September 1956, with the Operation Buffalo series. 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

10494-536: Was later used in the Vietnam War . During a firefight in May 1969, 169041 (call sign 24C) was hit by a rocket-propelled grenade (RPG) but remained battle-worthy. The Atomic Tank is now located at Robertson Barracks in Holtze, Northern Territory . Although other tanks were subjected to nuclear tests, 169041 is the only one known to have done so and then gone on to serve for another 23 years, including 15 months in

10600-561: Was made an Officer of the Order of the British Empire and Garden was made a Member of the Order of the British Empire . In addition to conclusively answering the questions about plutonium-240 that was their primary purpose, the Totem tests taught the British scientists a great deal about how to conduct trials, and how to measure fallout. For subsequent tests, monitoring stations would be established across Australia. A few days after

10706-788: 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

10812-505: Was offset by the value of the plutonium produced, which was about £100 per gram (£3,100 per ounce). Construction of the first PIPPA commenced at Calder Hall in March 1953. For cost reasons PIPPA was to operate in such a way that there would be a higher proportion of plutonium-240 present with the plutonium-239 product than in the Windscale-produced material. Since plutonium-240 is prone to spontaneous fission , this increased

10918-463: 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

11024-479: Was published in 2022. Operation Totem Operation Totem was a pair of British atmospheric nuclear tests which took place at Emu Field in South Australia in October 1953. They followed the Operation Hurricane test of the first British atomic bomb, which had taken place at the Montebello Islands a year previously. The main purpose of the trial was to determine the acceptable limit on

11130-968: Was responsible for the test series, and the Australian Army was so designated. The task of coordinating the construction phase was given to Brigadier Leonard Lucas . Lucas was an architect who had been the Deputy Engineer in Chief of the Australian Army during the Second World War. When he was given the assignment on 6 January 1953, he was the Regional Director of the Commonwealth Department of Works in Perth . Squadron Leader Kenneth Garden

11236-649: 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

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