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46-513: The Tuwaitha Nuclear Research Center was the main nuclear site in Iraq that was involved with handling nuclear material. It was started in 1967 when three main nuclear facilities and waste location were put in operation. These were the IRT 2000 research reactor, the radioisotope production building and the dumping station (waste store). Many other nuclear facilities were subsequently constructed at this site, and

92-466: A class of atoms characterized by their number of protons , Z , their number of neutrons , N , and their nuclear energy state . The word nuclide was coined by the American nuclear physicist Truman P. Kohman in 1947. Kohman defined nuclide as a "species of atom characterized by the constitution of its nucleus" containing a certain number of neutrons and protons. The term thus originally focused on

138-624: A collection of atoms of a single nuclide the decay rate, and thus the half-life ( t 1/2 ) for that collection, can be calculated from their measured decay constants . The range of the half-lives of radioactive atoms has no known limits and spans a time range of over 55 orders of magnitude. Radionuclides occur naturally or are artificially produced in nuclear reactors , cyclotrons , particle accelerators or radionuclide generators . There are about 730 radionuclides with half-lives longer than 60 minutes (see list of nuclides ). Thirty-two of those are primordial radionuclides that were created before

184-402: A complete tabulation). They include 30 nuclides with measured half-lives longer than the estimated age of the universe (13.8 billion years ), and another four nuclides with half-lives long enough (> 100 million years) that they are radioactive primordial nuclides , and may be detected on Earth, having survived from their presence in interstellar dust since before the formation of

230-468: A nonoptimal number of neutrons or protons decay by beta decay (including positron decay), electron capture or more exotic means, such as spontaneous fission and cluster decay . The majority of stable nuclides are even-proton–even-neutron, where all numbers Z , N , and A are even. The odd- A stable nuclides are divided (roughly evenly) into odd-proton–even-neutron, and even-proton–odd-neutron nuclides. Odd-proton–odd-neutron nuclides (and nuclei) are

276-414: A number of factors, and "can damage the functions of healthy tissue/organs. Radiation exposure can produce effects ranging from skin redness and hair loss, to radiation burns and acute radiation syndrome . Prolonged exposure can lead to cells being damaged and in turn lead to cancer. Signs of cancerous cells might not show up until years, or even decades, after exposure." Following is a summary table for

322-418: A result of rare events such as spontaneous fission or uncommon cosmic ray interactions. Radionuclides are produced as an unavoidable result of nuclear fission and thermonuclear explosions . The process of nuclear fission creates a wide range of fission products , most of which are radionuclides. Further radionuclides can be created from irradiation of the nuclear fuel (creating a range of actinides ) and of

368-544: A secret vault 40 meters below the reactor core would not be very effective, to which Israel responded by correcting their original statement to 4 meters. The IAEA was aware of such a vault but the reactor floor was shielded and the vault contained the mechanisms for raising the control rods which requires access for maintenance. According to the Director of the IAEA, the shielding would block the neutrons needed to turn U-238 into Pu-239 and

414-555: A set of nuclides with equal proton number and equal mass number (thus making them by definition the same isotope), but different states of excitation. An example is the two states of the single isotope 43 Tc shown among the decay schemes . Each of these two states (technetium-99m and technetium-99) qualifies as a different nuclide, illustrating one way that nuclides may differ from isotopes (an isotope may consist of several different nuclides of different excitation states). The longest-lived non- ground state nuclear isomer

460-514: A stable nucleus (see graph). For example, although the neutron–proton ratio of 2 He is 1:2, the neutron–proton ratio of 92 U is greater than 3:2. A number of lighter elements have stable nuclides with the ratio 1:1 ( Z = N ). The nuclide 20 Ca (calcium-40) is observationally the heaviest stable nuclide with the same number of neutrons and protons. All stable nuclides heavier than calcium-40 contain more neutrons than protons. The proton–neutron ratio

506-790: Is 138 times rarer. About 34 of these nuclides have been discovered (see List of nuclides and Primordial nuclide for details). The second group of radionuclides that exist naturally consists of radiogenic nuclides such as Ra (t 1/2 = 1602 years ), an isotope of radium , which are formed by radioactive decay . They occur in the decay chains of primordial isotopes of uranium or thorium. Some of these nuclides are very short-lived, such as isotopes of francium . There exist about 51 of these daughter nuclides that have half-lives too short to be primordial, and which exist in nature solely due to decay from longer lived radioactive primordial nuclides. The third group consists of nuclides that are continuously being made in another fashion that

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552-434: Is a nuclide that has excess numbers of either neutrons or protons , giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation ; transferred to one of its electrons to release it as a conversion electron ; or used to create and emit a new particle ( alpha particle or beta particle ) from the nucleus. During those processes,

598-507: Is a summary table for the 905 nuclides with half-lives longer than one hour, given in list of nuclides . Note that numbers are not exact, and may change slightly in the future, if some "stable" nuclides are observed to be radioactive with very long half-lives. Atomic nuclei other than hydrogen 1 H have protons and neutrons bound together by the residual strong force . Because protons are positively charged, they repel each other. Neutrons, which are electrically neutral, stabilize

644-521: Is a summary table for the 989 nuclides with half-lives longer than one hour (including those that are stable), given in list of nuclides . This list covers common isotopes, most of which are available in very small quantities to the general public in most countries. Others that are not publicly accessible are traded commercially in industrial, medical, and scientific fields and are subject to government regulation. Nuclide Nuclides (or nucleides , from nucleus , also known as nuclear species) are

690-593: Is called a radiopharmaceutical . On Earth, naturally occurring radionuclides fall into three categories: primordial radionuclides, secondary radionuclides, and cosmogenic radionuclides. Many of these radionuclides exist only in trace amounts in nature, including all cosmogenic nuclides. Secondary radionuclides will occur in proportion to their half-lives, so short-lived ones will be very rare. For example, polonium can be found in uranium ores at about 0.1 mg per metric ton (1 part in 10 ). Further radionuclides may occur in nature in virtually undetectable amounts as

736-403: Is made by cosmic ray bombardment of other elements, and nucleogenic Pu which is still being created by neutron bombardment of natural U as a result of natural fission in uranium ores. Cosmogenic nuclides may be either stable or radioactive. If they are stable, their existence must be deduced against a background of stable nuclides, since every known stable nuclide

782-481: Is negligible for most elements. Even in the case of the very lightest elements, where the ratio of neutron number to atomic number varies the most between isotopes, it usually has only a small effect, but it matters in some circumstances. For hydrogen, the lightest element, the isotope effect is large enough to affect biological systems strongly. In the case of helium, helium-4 obeys Bose–Einstein statistics , while helium-3 obeys Fermi–Dirac statistics . Since isotope

828-585: Is not simple spontaneous radioactive decay (i.e., only one atom involved with no incoming particle) but instead involves a natural nuclear reaction . These occur when atoms react with natural neutrons (from cosmic rays, spontaneous fission , or other sources), or are bombarded directly with cosmic rays . The latter, if non-primordial, are called cosmogenic nuclides . Other types of natural nuclear reactions produce nuclides that are said to be nucleogenic nuclides. An example of nuclides made by nuclear reactions, are cosmogenic C ( radiocarbon ) that

874-472: Is not the only factor affecting nuclear stability. It depends also on even or odd parity of its atomic number Z , neutron number N and, consequently, of their sum, the mass number A . Oddness of both Z and N tends to lower the nuclear binding energy , making odd nuclei, generally, less stable. This remarkable difference of nuclear binding energy between neighbouring nuclei, especially of odd- A isobars , has important consequences: unstable isotopes with

920-495: Is present on Earth primordially. Beyond the naturally occurring nuclides, more than 3000 radionuclides of varying half-lives have been artificially produced and characterized. The known nuclides are shown in Table of nuclides . A list of primordial nuclides is given sorted by element, at List of elements by stability of isotopes . List of nuclides is sorted by half-life, for the 905 nuclides with half-lives longer than one hour. This

966-473: Is the nuclide tantalum-180m ( 73 Ta ), which has a half-life in excess of 1,000 trillion years. This nuclide occurs primordially, and has never been observed to decay to the ground state. (In contrast, the ground state nuclide tantalum-180 does not occur primordially, since it decays with a half life of only 8 hours to Hf (86%) or W (14%).) There are 251 nuclides in nature that have never been observed to decay. They occur among

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1012-585: Is the older term, it is better known than nuclide , and is still occasionally used in contexts in which nuclide might be more appropriate, such as nuclear technology and nuclear medicine. Although the words nuclide and isotope are often used interchangeably, being isotopes is actually only one relation between nuclides. The following table names some other relations. A nuclide and its alpha decay product are isodiaphers. (Z 1 = N 2 and Z 2 = N 1 ) but with different energy states A set of nuclides with equal proton number ( atomic number ), i.e., of

1058-588: The Raytheon Corporation . Complete control of the facility was turned over to Iraqi authorities in the Summer of 2004. During American occupation the complex was looted, mostly for scrap lead. Lead-lined barrels and containers were emptied on-site then taken to a nearby improvised lead foundry then smelted into ingots. The operation was conducted in two parts. The first was a highly orchestrated event requiring industrial machinery in which large pieces of shielding from

1104-460: The Solar System , about 4.6 billion years ago. Another 60+ short-lived nuclides can be detected naturally as daughters of longer-lived nuclides or cosmic-ray products. The remaining known nuclides are known solely from artificial nuclear transmutation . Numbers are not exact, and may change slightly in the future, as "stable nuclides" are observed to be radioactive with very long half-lives. This

1150-528: The list of 989 nuclides with half-lives greater than one hour. A total of 251 nuclides have never been observed to decay, and are classically considered stable. Of these, 90 are believed to be absolutely stable except to proton decay (which has never been observed), while the rest are " observationally stable " and theoretically can undergo radioactive decay with extremely long half-lives. The remaining tabulated radionuclides have half-lives longer than 1 hour, and are well-characterized (see list of nuclides for

1196-459: The 64 kg used in Little Boy . 52 kg of 93% HEU is the minimum critical mass required to create a uranium bomb. They did not have the technical capabilities or resources to produce an implosion type device that uses less U-235 but requires complex lenses and initiators. During the initial months of the occupation, Tuwaitha was protected by American forces and administered by contractors from

1242-400: The 80 different elements that have one or more stable isotopes. See stable nuclide and primordial nuclide . Unstable nuclides are radioactive and are called radionuclides . Their decay products ('daughter' products) are called radiogenic nuclides . Natural radionuclides may be conveniently subdivided into three types. First, those whose half-lives t 1/2 are at least 2% as long as

1288-523: The Earth was formed. At least another 60 radionuclides are detectable in nature, either as daughters of primordial radionuclides or as radionuclides produced through natural production on Earth by cosmic radiation. More than 2400 radionuclides have half-lives less than 60 minutes. Most of those are only produced artificially, and have very short half-lives. For comparison, there are about 251 stable nuclides . All chemical elements can exist as radionuclides. Even

1334-473: The IRT 2000 reactor was also upgraded to IRT 5000. Until 1991, the facility was a nuclear research facility supposedly under the direction of Khidir Hamza . The facility is surrounded by a sand berm four miles (6.4 km) around and 160 feet (50 m) high, and contained the French-built research reactor Osirak , destroyed by Israel in 1981. Israel contended that there was a secret underground compartment for

1380-477: The Iraqi economy lacking the industrial infrastructure to support such an effort. Although the Iraqi government was able to smuggle some steel and carbon-fiber centrifuge units into the country, they needed at least a thousand to process industrial quantities. Without wide availability of extremely high precision instrumentation and production facilities, the task was impossible under anti-proliferation embargoes. Russia and

1426-439: The U.S.A. only developed the high-precision machining technology required during the space race . The 18 facilities and radwaste locations on this site and included within the decommissioning project are as follows: 33°12′18″N 44°30′54″E  /  33.20500°N 44.51500°E  / 33.20500; 44.51500 Radioisotope A radionuclide ( radioactive nuclide , radioisotope or radioactive isotope )

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1472-574: The age of the Earth (for practical purposes, these are difficult to detect with half-lives less than 10% of the age of the Earth) ( 4.6 × 10  years ). These are remnants of nucleosynthesis that occurred in stars before the formation of the Solar System . For example, the isotope U (t 1/2 = 4.5 × 10  years ) of uranium is still fairly abundant in nature, but the shorter-lived isotope U (t 1/2 = 0.7 × 10  years )

1518-603: The air in the detector's ionization chamber . A small electric voltage is applied to the ionized air which gives rise to a small electric current. In the presence of smoke, some of the ions are neutralized, thereby decreasing the current, which activates the detector's alarm. Radionuclides that find their way into the environment may cause harmful effects as radioactive contamination . They can also cause damage if they are excessively used during treatment or in other ways exposed to living beings, by radiation poisoning . Potential health damage from exposure to radionuclides depends on

1564-431: The combination of chemical properties and their radiation (tracers, biopharmaceuticals). The following table lists properties of selected radionuclides illustrating the range of properties and uses. Key: Z  =  atomic number ; N  =  neutron number ; DM = decay mode; DE = decay energy; EC =  electron capture Radionuclides are present in many homes as they are used inside

1610-499: The destroyed reactors was stolen. The second involved local villagers carrying items on hand-carts. At most 10 kg of uranium was lost in what could easily be explained as minor contamination by a few grams of dust per vessel of the more than 200 containers stolen. Research conducted at the complex produced novel results necessary to establish a self-sufficient nuclear program. Gas centrifuge, laser isotopic separation and gas diffusion technology were investigated but abandoned due to

1656-411: The lightest element, hydrogen , has a well-known radionuclide, tritium . Elements heavier than lead , and the elements technetium and promethium , exist only as radionuclides. Unplanned exposure to radionuclides generally has a harmful effect on living organisms including humans, although low levels of exposure occur naturally without harm. The degree of harm will depend on the nature and extent of

1702-433: The most common household smoke detectors . The radionuclide used is americium-241 , which is created by bombarding plutonium with neutrons in a nuclear reactor. It decays by emitting alpha particles and gamma radiation to become neptunium-237 . Smoke detectors use a very small quantity of Am (about 0.29 micrograms per smoke detector) in the form of americium dioxide . Am is used as it emits alpha particles which ionize

1748-405: The nucleus in two ways. Their copresence pushes protons slightly apart, reducing the electrostatic repulsion between the protons, and they exert the attractive nuclear force on each other and on protons. For this reason, one or more neutrons are necessary for two or more protons to be bound into a nucleus. As the number of protons increases, so does the ratio of neutrons to protons necessary to ensure

1794-481: The nucleus. A nuclide is a species of an atom with a specific number of protons and neutrons in the nucleus, for example carbon-13 with 6 protons and 7 neutrons. The nuclide concept (referring to individual nuclear species) emphasizes nuclear properties over chemical properties, while the isotope concept (grouping all atoms of each element) emphasizes chemical over nuclear. The neutron number has large effects on nuclear properties, but its effect on chemical reactions

1840-402: The production of plutonium. Plutonium is produced in breeder reactors by surrounding a neutron source, such as a nuclear reactor, with a 'blanket' of U-238. The neutrons released by nuclear fission are donated, producing Pu-239 and is the cheapest and easiest way to achieve large-scale production of plutonium. The director of the IAEA, which conducted regular inspections of the complex, argued that

1886-442: The radiation produced, the amount and nature of exposure (close contact, inhalation or ingestion), and the biochemical properties of the element; with increased risk of cancer the most usual consequence. However, radionuclides with suitable properties are used in nuclear medicine for both diagnosis and treatment. An imaging tracer made with radionuclides is called a radioactive tracer . A pharmaceutical drug made with radionuclides

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1932-474: The radionuclide is said to undergo radioactive decay . These emissions are considered ionizing radiation because they are energetic enough to liberate an electron from another atom. The radioactive decay can produce a stable nuclide or will sometimes produce a new unstable radionuclide which may undergo further decay. Radioactive decay is a random process at the level of single atoms: it is impossible to predict when one particular atom will decay. However, for

1978-513: The reactor would not be able to operate if the vault was blocked by being filled with uranium. As the sole reactor site in Iraq, the reactors relied on fuel imported from France and was unable to produce significant quantities of enriched uranium. In 1991, If Iraq had converted their entire stockpile of nuclear fuel rods, assuming they were able to perform the extremely difficult task of separation from highly irradiated fuel which contained 69 elements, they would only have 41 kg of U-235, less than

2024-498: The same chemical element but different neutron numbers , are called isotopes of the element. Particular nuclides are still often loosely called "isotopes", but the term "nuclide" is the correct one in general (i.e., when Z is not fixed). In similar manner, a set of nuclides with equal mass number A , but different atomic number , are called isobars (isobar = equal in weight), and isotones are nuclides of equal neutron number but different proton numbers. Likewise, nuclides with

2070-415: The same neutron excess ( N  −  Z ) are called isodiaphers. The name isoto n e was derived from the name isoto p e to emphasize that in the first group of nuclides it is the number of neutrons (n) that is constant, whereas in the second the number of protons (p). See Isotope#Notation for an explanation of the notation used for different nuclide or isotope types. Nuclear isomers are members of

2116-490: The surrounding structures, yielding activation products . This complex mixture of radionuclides with different chemistries and radioactivity makes handling nuclear waste and dealing with nuclear fallout particularly problematic. Synthetic radionuclides are deliberately synthesised using nuclear reactors , particle accelerators or radionuclide generators: Radionuclides are used in two major ways: either for their radiation alone ( irradiation , nuclear batteries ) or for

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