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109-668: 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 the amount of plutonium-240 which could be present in

218-693: 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,

327-531: 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 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

436-479: 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 a nuclear weapons project, code-named Tube Alloys , which

545-765: A detachment in Brunei , to support British forces stationed there to deter further aggression by Malayan communist guerrillas. The type also saw combat service with the RAF during the Cyprus Emergency and the Aden Emergency , in addition to other operations. In December 1971, the last of the RAF's Sycamores were officially retired; this had been due to critical parts having reached the end of their fatigue life. However 32 Squadron continued to operate two Sycamores until August 1972. Fifty Sycamores were delivered to

654-579: A four-door design, which had been standardised upon the Sycamore Mk.4. This version entered RAF service, receiving the military designation of HR.14. Civil versions were not marketed under the Sycamore name, they were instead known simply as the Bristol Type 171. By May 1958, over 150 Sycamores had been manufactured and four units per month were being built. The Bristol Sycamore was one of

763-421: A given weapon type for a country is included, as well as tests that were otherwise notable (such as the largest test ever). All yields (explosive power) are given in their estimated energy equivalents in kilotons of TNT (see TNT equivalent ). Putative tests (like Vela incident ) have not been included. Bristol Sycamore The Bristol Type 171 Sycamore is an early helicopter developed and built by

872-650: 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

981-506: A number of populated islands in nearby atoll formations. Though they were soon evacuated, many of the islands' inhabitants suffered from radiation burns and later from other effects such as increased cancer rate and birth defects, as did the crew of the Japanese fishing boat Daigo Fukuryū Maru . One crewman died from radiation sickness after returning to port, and it was feared that the radioactive fish they had been carrying had made it into

1090-716: 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

1199-532: A result of a scenario of a concentrated number of nuclear explosions in a nuclear holocaust , the thousands of tests, hundreds being atmospheric, did nevertheless produce a global fallout that has peaked in 1963 (the Bomb pulse ), reaching levels of about 0.15  mSv per year worldwide, or about 7% of average background radiation dose from all sources, and has slowly decreased since, with natural environmental radiation levels being around 1 mSv . This global fallout

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1308-473: A single salvo test; Pakistan's second and last official test exploded four different devices. Almost all lists in the literature are lists of tests; in the lists in Misplaced Pages (for example, Operation Cresset has separate items for Cremino and Caerphilly , which together constitute a single test), the lists are of explosions. Separately from these designations, nuclear tests are also often categorized by

1417-447: A variety of fissile material compositions, densities, shapes, and reflectors . They can be subcritical or supercritical, in which case significant radiation fluxes can be produced. This type of test has resulted in several criticality accidents . Subcritical (or cold) tests are any type of tests involving nuclear materials and possibly high explosives (like those mentioned above) that purposely result in no yield . The name refers to

1526-649: 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

1635-488: Is very unlikely to develop significant nuclear innovations without testing. One other approach is to use supercomputers to conduct "virtual" testing, but codes need to be validated against test data. There have been many attempts to limit the number and size of nuclear tests; the most far-reaching is the Comprehensive Test Ban Treaty of 1996, which has not, as of 2013 , been ratified by eight of

1744-430: The Aden Emergency , in addition to other operations. In addition to its British military service, various models of the Sycamore were produced and operated by a number of users, including overseas military operations and civil customers. Civilian operations typically involved transportation, mountain rescue, and aerial survey work. In 1959, production of the Sycamore ended after 180 rotorcraft had been completed. During

1853-517: 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

1962-820: 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 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

2071-662: The Marshall Islands on November 1, 1952 (local date), also by the United States. The largest nuclear weapon ever tested was the Tsar Bomba of the Soviet Union at Novaya Zemlya on October 30, 1961, with the largest yield ever seen, an estimated 50–58 megatons . With the advent of nuclear technology and its increasing impact an anti-nuclear movement formed and in 1963, three (UK, US, Soviet Union) of

2180-567: 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

2289-642: The Second World War , new methods of aircraft propulsion were devised and experimented with; in particular, breakthroughs in rotary aircraft, such as gyrocopters and helicopters , were making such aircraft more practical. In 1944, Bristol established a specialised helicopter division shortly after the Allied invasion of Europe , when engineers from the Airborne Forces Experimental Establishment (AFEE) at Beaulieu became available. The AFEE had been conducting its own work on

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2398-524: The Vela incident . From the first nuclear test in 1945 until tests by Pakistan in 1998, there was never a period of more than 22 months with no nuclear testing. June 1998 to October 2006 was the longest period since 1945 with no acknowledged nuclear tests. A summary table of all the nuclear testing that has happened since 1945 is here: Worldwide nuclear testing counts and summary . While nuclear weapons testing did not produce scenarios like nuclear winter as

2507-474: The " Annex 2 countries " required for it to take effect, including the United States. Nuclear testing has since become a controversial issue in the United States, with a number of politicians saying that future testing might be necessary to maintain the aging warheads from the Cold War . Because nuclear testing is seen as furthering nuclear arms development, many are opposed to future testing as an acceleration of

2616-647: 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 a resurgence of United States isolationism , and Britain losing its great power status,

2725-706: 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

2834-758: 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 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

2943-536: 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

3052-515: The Bristol range), performed the type's maiden flight . In mid-1948, the third prototype, which had been built to the improved Sycamore Mk.2 standard, was completed; this model had been fitted with a 550-horsepower (410 kW) Alvis Leonides engine, the Leonides engine would become the standard powerplant for all subsequent Sycamore production. On 25 April 1949, a certificate of airworthiness

3161-590: The British government for two tests to take place in October 1953: one of the Blue Danube type but with 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

3270-481: 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 the acceptable limit of the amount of plutonium-240 that could be present in a bomb. The plutonium used in

3379-490: 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

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3488-539: The CTBT has been signed by 183 States, of which 157 have also ratified. However, for the Treaty to enter into force it needs to be ratified by 44 specific nuclear technology-holder countries. These "Annex 2 States" participated in the negotiations on the CTBT between 1994 and 1996 and possessed nuclear power or research reactors at that time. The ratification of eight Annex 2 states is still missing: China, Egypt, Iran, Israel and

3597-587: 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 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 ,

3706-472: 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

3815-821: The German Federal Government. Three helicopters were produced for the Belgian Government for use in the Belgian Congo ; it had been picked due to the type's good capabilities in tropical environments, as proven during its combat use in Malaysia. The Sycamore was the second helicopter type to be used by the Australian Defence Force ; ten were delivered to the Royal Australian Navy . The Sycamore

3924-614: 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 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

4033-600: The Japanese food supply. Castle Bravo was the worst U.S. nuclear accident, but many of its component problems—unpredictably large yields, changing weather patterns, unexpected fallout contamination of populations and the food supply—occurred during other atmospheric nuclear weapons tests by other countries as well. Concerns over worldwide fallout rates eventually led to the Partial Test Ban Treaty in 1963, which limited signatories to underground testing. Not all countries stopped atmospheric testing, but because

4142-506: The Mk.3A retained the standard two-seat cockpit layout, placing the pilot in the left-hand seat and the co-pilot in the right. However, on the main production model, designated Sycamore Mk.4, this seating arrangement was switched to the American practice of positioning the pilot's seat on the right. There were also a number of other developments that had featured upon the earlier versions, such as

4251-792: 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

4360-498: 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

4469-701: The Partial Nuclear Test Ban Treaty. The 1996 Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans all nuclear explosions everywhere, including underground. For that purpose, the Preparatory Commission of the Comprehensive Nuclear-Test-Ban Treaty Organization is building an international monitoring system with 337 facilities located all over the globe. 85% of these facilities are already operational. As of May 2012 ,

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4578-497: The RAF and went on to serve with nine squadrons in total. Various marks of Sycamore served with the RAF; they would primarily be used as air ambulances ( Sycamore HC.10 ), for Army communications ( Sycamore HC.11 ) and for search and rescue operations (Sycamore HR.12 to Sycamore HR.14). In 1953, No. 275 Squadron, equipped with Sycamores, became the RAF's first helicopter search and rescue squadron in Great Britain. The type

4687-627: The UK Ministry of Supply staff in Melbourne and Omond Solandt from the Canadian Defence Research Board . The party inspected 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

4796-529: 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

4905-891: The United Kingdom until 1991, the United States until 1992, and both China and France until 1996. In signing the Comprehensive Nuclear-Test-Ban Treaty in 1996, these countries pledged to discontinue all nuclear testing; the treaty has not yet entered into force because of its failure to be ratified by eight countries. Non-signatories India and Pakistan last tested nuclear weapons in 1998. North Korea conducted nuclear tests in 2006 , 2009 , 2013 , January 2016 , September 2016 and 2017. The most recent confirmed nuclear test occurred in September 2017 in North Korea. Nuclear weapons tests have historically been divided into four categories reflecting

5014-564: The United States and the Soviet Union were responsible for roughly 86% of all nuclear tests, their compliance cut the overall level substantially. France continued atmospheric testing until 1974, and China until 1980. A tacit moratorium on testing was in effect from 1958 to 1961 and ended with a series of Soviet tests in late 1961, including the Tsar Bomba , the largest nuclear weapon ever tested. The United States responded in 1962 with Operation Dominic , involving dozens of tests, including

5123-457: The United States have signed but not ratified the Treaty; India, North Korea and Pakistan have not signed it. The following is a list of the treaties applicable to nuclear testing: Over 500 atmospheric nuclear weapons tests were conducted at various sites around the world from 1945 to 1980. As public awareness and concern mounted over the possible health hazards associated with exposure to the nuclear fallout , various studies were done to assess

5232-408: The acting Prime Minister, Arthur Fadden , signalled his approval for the tests from Australia. The test series 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

5341-410: 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

5450-409: The amount of it that is necessary. Hydronuclear tests study nuclear materials under the conditions of explosive shock compression. They can create subcritical conditions, or supercritical conditions with yields ranging from negligible all the way up to a substantial fraction of full weapon yield. Critical mass experiments determine the quantity of fissile material required for criticality with

5559-417: The arms race. In total nuclear test megatonnage , from 1945 to 1992, 520 atmospheric nuclear explosions (including eight underwater) were conducted with a total yield of 545 megatons , with a peak occurring in 1961–1962, when 340 megatons were detonated in the atmosphere by the United States and Soviet Union , while the estimated number of underground nuclear tests conducted in the period from 1957 to 1992

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5668-477: 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 ,

5777-482: The burial points of all explosive devices can be connected by segments of straight lines, each of them connecting two burial points, and the total length does not exceed 40 kilometers. For nuclear weapon tests, a salvo is defined as two or more underground nuclear explosions conducted at a test site within an area delineated by a circle having a diameter of two kilometers and conducted within a total period of time of 0.1 seconds. The USSR has exploded up to eight devices in

5886-576: 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

5995-565: 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

6104-410: The conflict; however, the type was involved in a number of crashes in the region which had occurred as a result of tail or main rotor blade problems. In response, a series of blade trials were conducted prior to a modified blade design being adopted and Sycamore operations in the theatre being resumed. Following the end of most combat operations in August 1960, Sycamores remained in the region, including

6213-456: 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

6322-448: The development of rotorcraft designs under the noted helicopter pioneer Raoul Hafner ; however, the successful use of Airspeed Horsa and General Aircraft Hamilcar gliders during Operation Overlord had led to helicopter development being recognised as a priority. Hafner, whose company had been acquired by Bristol was promptly appointed by the company as the head of Bristol's new helicopter division. In June 1944, work commenced on

6431-457: The development on a four-seat helicopter intended for both civil and military use; it was out of this programme that the Sycamore would emerge. During development, particular emphasis was assigned to the producing the necessary level of endurance of the rotorcraft's mechanical components. On 25 July 1947, the first prototype, VL958, which was powered by a 450-horsepower (340 kW) Pratt & Whitney Wasp Junior (there being no suitable engine in

6540-486: 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

6649-668: The explosion of a missile launched from a submarine. Almost all new nuclear powers have announced their possession of nuclear weapons with a nuclear test. The only acknowledged nuclear power that claims never to have conducted a test was South Africa (although see Vela incident ), which has since dismantled all of its weapons. Israel is widely thought to possess a sizable nuclear arsenal, though it has never tested, unless they were involved in Vela. Experts disagree on whether states can have reliable nuclear arsenals—especially ones using advanced warhead designs, such as hydrogen bombs and miniaturized weapons—without testing, though all agree that it

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6758-441: The explosion's effects, it did not give an appreciable understanding of nuclear fallout , which was not well understood by the project scientists until well after the atomic bombings of Hiroshima and Nagasaki . The United States conducted six atomic tests before the Soviet Union developed their first atomic bomb ( RDS-1 ) and tested it on August 29, 1949. Neither country had very many atomic weapons to spare at first, and so testing

6867-405: The extent of the hazard. A Centers for Disease Control and Prevention / National Cancer Institute study claims that nuclear fallout might have led to approximately 11,000 excess deaths, most caused by thyroid cancer linked to exposure to iodine-131 . The following list is of milestone nuclear explosions. In addition to the atomic bombings of Hiroshima and Nagasaki , the first nuclear test of

6976-432: 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 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

7085-412: The first production helicopters to be developed. Each Sycamore was manufactured with all of the necessary fixed fittings to enable it to be quickly adapted for any of six major roles: search and rescue, air ambulance, passenger transport, freight transport, aerial crane and dual instruction; it was also used for other specialised roles. The Sycamore seated four-to-five occupants, depending on the model; it

7194-412: 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

7303-420: The formation of these treaties. Examples can be seen in the following articles: The Partial Nuclear Test Ban treaty makes it illegal to detonate any nuclear explosion anywhere except underground, in order to reduce atmospheric fallout. Most countries have signed and ratified the Partial Nuclear Test Ban, which went into effect in October 1963. Of the nuclear states, France, China, and North Korea have never signed

7412-455: The helicopter division of the Bristol Aeroplane Company . The name refers to the seeds of the sycamore tree, Acer pseudoplatanus , which fall with a rotating motion. It has the distinction of being the first British helicopter to receive a certificate of airworthiness , as well as being the first British-designed helicopter to be introduced by and to serve with the Royal Air Force (RAF). Typically capable of seating up to three passengers,

7521-416: The helicopter, designated as the Sycamore Mk.3, was rapidly developed; it featured an increased capacity for five occupants, a wider fuselage and a shortened nose. A total of 23 Sycamore Mk.3s were produced, 15 of these were principally used for joint evaluation purposes by the Royal Air Force (RAF), Army Air Corps (AAC), and British European Airways (BEA). Versions of the Sycamore up to and including

7630-438: The lack of creation of a critical mass of fissile material. They are the only type of tests allowed under the interpretation of the Comprehensive Nuclear-Test-Ban Treaty tacitly agreed to by the major atomic powers. Subcritical tests continue to be performed by the United States, Russia, and the People's Republic of China, at least. Subcritical tests executed by the United States include: The first atomic weapons test

7739-409: The later phases of the Cold War , though, both countries developed accelerated testing programs, testing many hundreds of bombs over the last half of the 20th century. Atomic and nuclear tests can involve many hazards. Some of these were illustrated in the U.S. Castle Bravo test in 1954. The weapon design tested was a new form of hydrogen bomb, and the scientists underestimated how vigorously some of

7848-474: 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

7957-455: The medium or location of the test. Another way to classify nuclear tests is by the number of explosions that constitute the test. The treaty definition of a salvo test is: In conformity with treaties between the United States and the Soviet Union, a salvo is defined, for multiple explosions for peaceful purposes, as two or more separate explosions where a period of time between successive individual explosions does not exceed 5 seconds and where

8066-520: The military effects of atomic weapons ( Crossroads had involved the effect of atomic weapons on a navy, and how they functioned underwater) and to test new weapon designs. During the 1950s, these included new hydrogen bomb designs, which were tested in the Pacific, and also new and improved fission weapon designs. The Soviet Union also began testing on a limited scale, primarily in Kazakhstan . During

8175-435: 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

8284-535: 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 the design was known as PIPPA, for pressurised pile producing power and plutonium. Although PIPPA produced less plutonium than

8393-399: 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

8502-403: The pilot was a swivelling seat for a medical attendant. The blades of the three-bladed main rotor were attached to the rotor head with lightweight interleaving steel plates while tie-rods carried the centrifugal tension loads. The blade levers were connected using ball joints to the arms of a control spider, the cone of which was actuated up and down by the collective pitch lever which changed

8611-401: The pitch of all the blades; an irreversible mechanism was used to prevent blade loads being transferred back to the control stick. The blades were supported when stationary or turning slowly by droop stops, which maintained a minimum clearance between the blade tips and the tailboom even in high winds; these stops were withdrawn above 100 rpm so that full freedom of movement for effective flight

8720-528: The purpose of the test itself. Aside from these technical considerations, tests have been conducted for political and training purposes, and can often serve multiple purposes. Computer simulation is used extensively to provide as much information as possible without physical testing. Mathematical models for such simulation model scenarios not only of performance but also of shelf life and maintenance . A theme has generally been that even though simulations cannot fully replace physical testing, they can reduce

8829-430: 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

8938-511: The then four nuclear states and many non-nuclear states signed the Limited Test Ban Treaty , pledging to refrain from testing nuclear weapons in the atmosphere, underwater, or in outer space . The treaty permitted underground nuclear testing . France continued atmospheric testing until 1974, and China continued until 1980. Neither has signed the treaty. Underground tests conducted by the Soviet Union continued until 1990,

9047-475: 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

9156-488: The type was often used as a transport for both passengers and cargo alike. In RAF service, the Sycamore was normally used in the search and rescue and casualty evacuation roles. The type proved the value of rotorcraft to easily traverse inhospitable or otherwise inaccessible terrain; the Sycamore made valuable contributions to British military activities during the Malayan Emergency , the Cyprus Emergency , and

9265-421: The usual arrangement of the era of using externally-mounted "pods" for carrying patients. To provide the extra width necessary in the cabin, detachable Perspex blisters were fitted on each side of the cabin. The stretcher racks could be folded into the sides of the cabin, providing room for up to three sitting casualties instead; an electrical supply outlet was available for connecting electric blankets . Next to

9374-455: The weapon materials would react. As a result, the explosion—with a yield of 15 Mt —was over twice what was predicted. Aside from this problem, the weapon also generated a large amount of radioactive nuclear fallout , more than had been anticipated, and a change in the weather pattern caused the fallout to spread in a direction not cleared in advance. The fallout plume spread high levels of radiation for over 100 miles (160 km), contaminating

9483-478: 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

9592-466: 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

9701-493: Was 1,352 explosions with a total yield of 90 Mt. The yields of atomic bombs and thermonuclear are typically measured in different amounts. Thermonuclear bombs can be hundreds or thousands of times stronger than their atomic counterparts. Due to this, thermonuclear bombs' yields are usually expressed in megatons which is about the equivalent of 1,000,000 tons of TNT. In contrast, atomic bombs' yields are typically measured in kilotons, or about 1,000 tons of TNT. In US context, it

9810-424: 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 the test arrived by road,

9919-571: Was achieved by twisting the pitch lever. The Sycamore had a relatively high rotor speed for the era, which was claimed to give a smoother ride and be safer in the event of engine failure. From 1952 to 1955 the Sycamore was used for various trials by the Air-Sea Warfare Development Unit RAF which was stationed at RAF St. Mawgan . In April 1953, the Sycamore HR14 entered service with No. 275 Squadron of

10028-523: Was also used in a variety of civilian roles. A single example was used during the construction of the M1 motorway between London and Leeds ; the type provided support in various roles, including to perform aerial surveying, communication across various sites, the carriage of both personnel and equipment, and the mitigation of flooding on the project. Sycamores operated by Australian National Airways were routinely available for charter, performing tasks such as

10137-469: Was appointed to the National Coal Board in May 1953, and was replaced by Charles Adams. In Australia, 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

10246-481: Was conducted near Alamogordo, New Mexico, on July 16, 1945, during the Manhattan Project , and given the codename " Trinity ". The test was originally to confirm that the implosion-type nuclear weapon design was feasible, and to give an idea of what the actual size and effects of a nuclear explosion would be before they were used in combat against Japan. While the test gave a good approximation of many of

10355-759: Was decided during the Manhattan Project that yield measured in tons of TNT equivalent could be imprecise. This comes from the range of experimental values of the energy content of TNT, ranging from 900 to 1,100 calories per gram (3,800 to 4,600 kJ/g). There is also the issue of which ton to use, as short tons, long tons, and metric tonnes all have different values. It was therefore decided that one kiloton would be equivalent to 1.0 × 10 calories (4.2 × 10  kJ). The nuclear powers have conducted more than 2,000 nuclear test explosions (numbers are approximate, as some test results have been disputed): There may also have been at least three alleged but unacknowledged nuclear explosions (see list of alleged nuclear tests ) including

10464-418: Was drawn through a forward-facing grill to cool the gearbox before passing through the engine cowling and leaving the fuselage. The engine power was controlled by the collective pitch lever. In order to maintain the rotor speed at its required setting fuel to the engine had to be automatically varied as the rotor pitch setting commanded by the pilot changed the load on the engine; fine adjustment of engine power

10573-713: Was estimated at £799,700. Unlike Hurricane, it was decided that it would be best if a single service 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

10682-782: 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 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

10791-521: Was granted for the Sycamore, the first such to be granted to a British helicopter. During the flight test programme, Bristol's key development pilots for the Type 171 included Charles "Sox" Hosegood and Col. Robert "Bob" Smith. In 1951, a Bristol-owned Sycamore Mk.2 was used during a series of deck landing trials performed on board the Royal Navy aircraft carrier HMS Triumph . An improved model of

10900-662: Was held in September 1956, with the Operation Buffalo series. Nuclear test The first nuclear device was detonated as a test by the United States at the Trinity site in New Mexico on July 16, 1945, with a yield approximately equivalent to 20 kilotons of TNT . The first thermonuclear weapon technology test of an engineered device, codenamed Ivy Mike , was tested at the Enewetak Atoll in

11009-536: 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

11118-559: 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

11227-720: Was one of the main drivers for the ban of nuclear weapons testing, particularly atmospheric testing. It has been estimated that by 2020 up to 2.4 million people have died as a result of nuclear weapons testing. There are many existing anti-nuclear explosion treaties, notably the Partial Nuclear Test Ban Treaty and the Comprehensive Nuclear Test Ban Treaty . These treaties were proposed in response to growing international concerns about environmental damage among other risks. Nuclear testing involving humans also contributed to

11336-410: Was possible. The Sycamore was powered by a single Alvis Leonides piston engine of 550 hp (410 kW). The engine was mounted below and to the rear of the main rotor on a flexible mounting to reduce vibrations transmitted to the helicopter structure. It was isolated in a fireproof enclosure which was fitted with fire detection and extinguishing equipment to meet certification requirements. Air

11445-443: Was relatively infrequent (when the U.S. used two weapons for Operation Crossroads in 1946, they were detonating over 20% of their current arsenal). However, by the 1950s the United States had established a dedicated test site on its own territory ( Nevada Test Site ) and was also using a site in the Marshall Islands ( Pacific Proving Grounds ) for extensive atomic and nuclear testing. The early tests were used primarily to discern

11554-501: 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 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

11663-622: 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 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,

11772-650: Was used by the RAF Central Flying School for pilot training purposes. In June 1953, a Sycamore towing a large RAF Ensign led a flypast by 640 British and Commonwealth aircraft at the Coronation Review of the RAF . The Sycamore was heavily used during the Malayan Emergency (1948–1960), typically deploying Army foot patrols into the jungle. Numerous Sycamores were transferred to the Far East Air Force to participate in

11881-408: Was usually fitted with three folding canvas seats as well as a single rotating seat besides the pilot. In addition to the passenger cabin, it had a separate luggage compartment. A specialised air ambulance model of the Sycamore was developed during the early 1950s. In this configuration, up to two patients were carried inside the cabin on stretchers stacked one above the other; this was different to

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