Nuclear reactors dysprosium

There are not many uses for dysprosium. Scientists continue to experiment with it as a possible alloy metal (it has a high melting point) to be mixed with steel to make control rods that absorb neutrons in nuclear reactors. There are only a few commercial uses for dysprosium, such as a laser material and as a fluorescence activator for the phosphors used to produce the colors in the older TV and computer cathode ray tubes (CRTs). When combined with steel or nickel as an alloy, it makes strong magnets. 

Californium is a transuranic element of the actinide series that is homologous with dysprosium (gjDy), just above it in the rare-earth lanthanide series. Cf-245 was the first isotope of californium that was artificially produced. It has a half-life of just 44 minutes. Isotopes of californium are made by subjecting berkelium to high-energy neutrons within nuclear reactors, as follows + (neutrons and A, gamma rays) — °Bk — °Cf + (3- (beta particle... 

Dysprosium is used in nuclear reactor fuels to measure neutron flux. It also is used as a fluorescence activator in phosphors. 

Dysprosium has a tendency to soak up neutrons, which are tiny particles that occur in atoms and are produced in nuclear reactions. Metal rods (control rods) containing dysprosium are used in nuclear reactors to control the rate at which neutrons are available. 

Like the element itself, some compounds of dysprosium are used in nuclear reactors and the manufacture of electrical and electronic equipment. 

Because europium, gadolinium (Gd), and dysprosium (Dy) are good absorbers of neutrons, they are used in control rods in nuclear reactors. Promethium (Pm) is the only synthetic element in the lanthanide series. 

A dysprosium oxide-nickel cermet is used in cooling nuclear-reactor rods. This cermet absorbs neutrons readily without swelling or contracting under prolonged neutron bombardment Another field of application is dosimeters for radioactive exposure (Emsley 2001). 

With radioisotopes now available for many elements, the tracer technique became generally applicable. New variants were developed, such as neutron activation analysis, which was introduced in 1936 for the determination of dysprosium in rare-earth samples (Hevesy and Levi 1936) and subsequently became a widely used technique for sensitive trace analyses, particularly when much larger neutron fluxes became available with the advent of nuclear reactors. Another frequently applied method for trace determination is isotope dilution the species to be determined in the sample is diluted by addition of a known amount of the same species labeled with known specific activity. From the specific activity then resulting and measured, the original quantity of the species is derived, even if only a fi action of the species is finally recovered. The impact on biosciences was revolutionary, when suitable isotopes of key elements in the biosphere were soon discovered (Ti/2 = 10 min) was one of I. Curie and... 

Dysprosium (Dy) Owing to its important thermal neutron cross section, dysprosium is used to produce control rods in nuclear reactors and also as a neutron flux measurement. The alloy Tb Dy Fe, is used as a magnetostrictive material. The alloy Nd-Fe-B is a permanent magnet. Finally, dysprosium is also used as phosphors, catalysts, and garnet microwave devices. 

Dysprosium has not yet found many applications. One important use, however, is in magnetostrictive materials, which have been described in the terbium section above. Another is in the dysprosium oxide-nickel cermet ), which is used for cooling nuclear reactor rods. This makes use of dysprosium s ability to absorb neutrons. 

The effect of a thermal-neutron absorber on the reactivity of a nuclear reactor is found experimentally as a function of the absorber position in the reactor. The relative thermal flux at each location of the absorber is determined by counting a wire, made of dysprosium dispersed in aluminum, which is irradiated in the reactor. The experimentally determined absorber importance function is compared with the importance function based on one-group perturbation theory, and a neutron importance in the reactor as a function of position is determined by comparison with the results of a two-group perturbation theory. 

By contrast, the metals have so far found only limited application save for one important use in the field of nondestructive testing. With the proliferation of research reactors over the past decade, neutron radiography has become a practical tool in the aerospace, nuclear and engineering industries, yet without the availability of gadolinium and dysprosium in the form of thin foils, the technique would be severely restricted. 

Activation analysis is the other field of radiochemical analysis that has become of major importance, particularly neutron activation analysis. In this method nuclear transformations are carried out by irradiation with neutrons. The nature and the intensity of the radiation emitted by the radionuclides formed are characteristic, respectively, of the nature and concentrations of the atoms irradiated. Activation analysis is one of the most sensitive methods, an important tool for the analysis of high-purity materials, and lends itself to automation. The technique was devised by Hevesy, who with Levi in 1936 determined dysprosium in yttrium by measuring the radiation of dysprosium after irradiation with neutrons from a Po-Be neutron source. At the time the nature of the radiation was characterized by half-life, and the only available neutron sources were Po-Be and Ra-Be, which were of low efficiency. Hevesy s paper was not followed up for many years. The importance of activation analysis increased dramatically after the emergence of accelerators and reactors in which almost all elements could be activated. Hevesy received the 1943 Nobel prize in chemistry for work on the use of isotopes as tracers in the study of chemical processes . 

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