Plutonium nuclear bombardment

Albert Ghiorso ( 1915), together with Stanley Gerald Thompson (1912-1967), Bernard G. Harvey, and Gregory Robert Choppin ( 1927). Produced from plutonium-239 by strong nuclear bombardment. 

Technetium is produced in nuclear reactors. A nuclear reactor is a device in which uranium or plutonium is bombarded with neutrons. The neutrons... 

Some elements are not foimd in nature but are produced artificially in particle accelerators like the one shown in Figure 3.10. These are known as synthetic elements. The synthetic elements, made by means of nuclear reactions, are marked on the periodic table. They include technetium, element 43, and all the elements after uranium, element 92. Although small amounts of neptunium and plutonium, elements 93 and 94, have been found in uranium ores, it is likely that they are the products of nuclear bombardment by radiation from uranium atoms. 

In 1964, workers at the Joint Nuclear Research Institute at Dubna (U.S.S.R.) bombarded plutonium with accelerated 113 to 115 MeV neon ions. By measuring fission tracks in a special glass with a microscope, they detected an isotope that decays by spontaneous fission. They suggested that this isotope, which had a half-life of 0.3 +/- 0.1 s might be 260-104, produced by the following reaction 242Pu + 22Ne —> 104 +4n. 

Neutron-rich lanthanide isotopes occur in the fission of uranium or plutonium and ate separated during the reprocessing of nuclear fuel wastes (see Nuclearreactors). Lanthanide isotopes can be produced by neutron bombardment, by radioactive decay of neighboring atoms, and by nuclear reactions in accelerators where the rate earths ate bombarded with charged particles. The rare-earth content of solid samples can be determined by neutron... 

Radioactivity occurs naturally in earth minerals containing uranium and thorium. It also results from two principal processes arising from bombardment of atomic nuclei by particles such as neutrons, ie, activation and fission. Activation involves the absorption of a neutron by a stable nucleus to form an unstable nucleus. An example is the neutron reaction of a neutron and cobalt-59 to yield cobalt-60 [10198 0-0] Co, a 5.26-yr half-life gamma-ray emitter. Another is the absorption of a neutron by uranium-238 [24678-82-8] to produce plutonium-239 [15117 8-5], Pu, as occurs in the fuel of a nuclear... 

Uranium-235 and U-238 behave differently in the presence of a controlled nuclear reaction. Uranium-235 is naturally fissile. A fissile element is one that splits when bombarded by a neutron during a controlled process of nuclear fission (like that which occurs in a nuclear reactor). Uranium-235 is the only naturally fissile isotope of uranium. Uranium-238 is fertile. A fertile element is one that is not itself fissile, but one that can produce a fissile element. When a U-238 atom is struck by a neutron, it likely will absorb the neutron to form U-239. Through spontaneous radioactive decay, the U-239 will turn into plutonium (Pu-239). This new isotope of plutonium is fissile, and if struck by a neutron, will likely split. 

Not all of the Pu-239 will fission during the fuel cycle in a nuclear reactor. Some of the plutonium will not experience neutron bombardment sufficient to cause fission. Other plutonium atoms will absorb one or more neutrons and become higher numbered isotopes of plutonium, such as Pu-240, Pu-241, etc. Plutonium comprises just over 1 percent of nuclear reactor spent fuel—the fuel removed from the... 

Induced nuclear fission is fission caused by bombarding a heavy nucleus with neutrons (Fig. 17.23). The nucleus breaks into two fragments when struck by a projectile. Nuclei that can undergo induced fission are called fissionable. For most nuclei, fission takes place only if the impinging neutrons travel so rapidly that they can smash into the nucleus and drive it apart with the shock of impact uranium-238 undergoes fission in this way. Fissile nuclei, however, are nuclei that can be nudged into breaking apart even by slow neutrons. They include uranium-235, uranium-233, and plutonium-239—the fuels of nuclear power plants. 

Write a nuclear equation for each of the following processes (a) oxygen-17 produced by a particle bombardment of nitrogen-14 (b) americium-240 produced by neutron bombardment of plutonium-239. 

Plutonium-239 was produced by the neutron bombardment of U. The first nuclear reactor, constructed at the... 

Artificial radioactive atoms are produced either as a by-product of fission of uranium or plutonium atoms in a nuclear reactor or by bombarding stable atoms with particles, such as neutrons or protons, directed at... 

Silvery white, artificial element that is also generated by intensive bombardment of plutonium with neutrons. It is a strong ("hot") neutron emitter and is used in microgram quantities in nuclear medicine. This reliable neutron source is also used in industry and science (for activation analysis). 

At one time, neptunium s entire existence was synthesized by man. Sometime later, in the mid-twentieth century, it was discovered that a very small amount is naturally produced in uranium ore through the actions of neutrons produced by the decay of uranium in the ore pitchblende. Even so, a great deal more neptunium is artificially produced every year than ever did or does exist in nature. Neptunium is recovered as a by-product of the commercial production of plutonium in nuclear reactors. It can also be synthesized by bombarding uranium-238 with neutrons, resulting in the production of neptunium-239, an isotope of neptunium with a half-life of 2.3565 days. 

Plutonium exists in trace amounts in nature. Most of it isotopes are radioactive and manmade or produced by the natural decay of uranium. Plutonium-239 is produced in nuclear reactors by bombarding uranium-238 with deuterons (nuclei of deuterium, or heavy hydrogen). The transmutation process is as follows + deuterons—> 2 nuclei + Np + p— ... 

Americium does not exist in nature. All of its isotopes are man-made and radioactive. Americium-241 is produced by bombarding plutonium-239 with high-energy neutrons, resulting in the isotope plutonium-240 that again is bombarded with neutrons and results in the formation of plutonium-241, which in turn finally decays into americium-241 by the process of beta decay. Both americium-241 and americium-243 are produced within nuclear reactors. The reaction is as follows Pu + (neutron and X gamma rays) —> " Pu + (neutron and X gamma rays) —> Pu—> Am + beta minus ([ -) followed by " Am—> jNp-237 + Hej (helium nuclei). 

There is no natural curium on Earth. All of its isotopes are man-made and artificially produced through nuclear reactions with other elements. The curium isotope Cm-242 was first produced by bombarding plutonium-239 with helium nuclei (alpha particles), which contributed neutrons that changed Pu to g Cm. 

In December 1998 the Lawrence Berkeley Laboratory sent a supply of plutonium-244 and calcium-48 to Russian scientists at the Joint Institute of Nuclear Research in Dubna, Russia. The Russians bombarded the plutonium with ions of calcium, which, after some time, produced a single atom of ununquadium-289. Uuq has a half-life of just 30 seconds, after which it decays successively into element 112 (ununbium), element 110, (darmstadtium), and element 108 (hassium). The Russian nuclear laboratory later synthesized several atoms of other isotopes of Ununquadium. 

Curium can be synthesized in a nuclear reactor by several methods. The first synthesis involved alpha particle bombardment of plutonium-239 ... 

Plutonium is produced from natural uranium which is a mixture of nonfis-sionable uranium-238 (99.3%) and fissionable uranium-235(0.7%). The first synthesis of this element was in a cyclotron generating plutonium in microgram quantities. The isotope Pu-239 can be produced in much larger quantities in a nuclear reactor, either a conventional thermal reactor or a breeder type reactor by neutron bombardment of uranium- 238. The nuclear reactions are shown below. 

There are several spaces in the Periodic Table between plutonium (element 94) and einsteinium (element 99). But by 1952 these had already been filled by scientists at Berkeley, using the cyclotron to bombard heavy nuclei with particles that, when captured, increased the nuclear mass. In 1944 Glenn Seaborg, Albert Ghiorso, and Ralph James made elements 95 and 96 this way. Kept secret until after the war, they were respectively called americium and curium. 

Fission weapons or bombs They derive their power from nuclear fission when heavy nuclei such as uranium (U) or plutonium (Pu) are bombarded by neutrons and split into lighter elements, more neutrons and energy. The newly generated neutrons then bombard other nuclei which then split and bombard other nuclei and so on. This process continues and leads to a nuclear chain reaction which releases large amount of energy. These are also historically called atomic bombs or atom bombs or A-bombs. 

Spent fuel from a reactor contains unused uranium as well as plutonium-239 which has been created by bombardment of neutrons during the fission process. Mixed with these useful materials are other highly radioactive and hazardous fission products, such as cesium-137 and strontium-90. Since reprocessed fuels contain plutonium, well suited for making nuclear weapons, concern has been expressed over the possible capture of some of this material by agents or terrorists operating on behalf of unfriendly governments that do not have a nuclear weapons capability. 

The identification of an isotope of element 95, by Seaborg, Ghiorso, James, and Leon Morgan in late 1944 and early 1945, followed the identification of this isotope of element 96 (242Cm) as a result of the bombardment of 7j Pu with neutrons in a nuclear reactor. The production reactions, involving multiple neutron capture by plutonium, are... 

Other nuclear transmutations can lead to the synthesis of entirely new elements never before seen on Earth. In fact, all the transuranium elements—those elements with atomic numbers greater than 92—have been produced by bombardment reactions. Plutonium, for example, can be made by bombarding uranium-238 with a particles ... 

After 1933 Fermi turned increasingly to experimental physics. Inspired by recent work in which artificial radioactive substances were produced by a-particle bombardment, Fermi and several collaborators used neutron bombardment to create several transuranic elements heavier than uranium, including plutonium. This work, and his finding that slow neutrons produce nuclear reactions more efficiently than fast ones, earned Fermi wide acclaim and the 1938 Nobel Prize in physics. After accepting the prize in Sweden, Fermi and his Jewish wife immigrated to the United States to escape the Nazis. 

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