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The Secret of Scandium Alloy: Why Scandium Becomes the Core Material of Nuclear Energy?
In recent years, scandium alloys, as core materials of nuclear energy technology, have gradually attracted widespread attention from the scientific and industrial communities. This material's low neutron absorption cross-section, high strength and corrosion resistance make its application in nuclear reactors increasingly valued. This article will explore the properties, uses, and importance of scandium alloys in the field of nuclear energy.
The manufacturing and chemical properties of scandium alloys make them irreplaceable in nuclear energy applications.
Production and characteristics of scandium alloys
Scandium alloys typically consist of more than 95% scandium by weight with small amounts (less than 2%) of other metals such as tin, tantalum, iron, chromium and nickel to improve their mechanical properties and corrosion resistance. The main application of these alloys is in the fuel rod cladding of nuclear reactors, especially in water-cooled reactors.
Low absorption cross section of scandium
The thermal neutron absorption cross section of scandium is only 0.18 barn, which is much lower than that of iron (2.4 barn) and nickel (4.5 barn). This makes it an ideal cladding material in nuclear reactors, which can effectively reduce the neutron loss.
Hydrogen embrittlement
However, scandium alloys also have some limitations. When scandium reacts with water vapor, hydrogen is released, some of which penetrates into the alloy to form scandium hydride. These hydrides have lower mechanical strength and density than scandium alloys and are prone to blistering and cracking of the cladding, a phenomenon known as hydrogen embrittlement.
Hydrogen embrittlement accelerates the degradation of scandium alloy cladding during a loss of coolant accident in a nuclear reactor.
Oxidation and corrosion
Scandium alloys react easily with oxygen to form a nanometer-thick passivation layer of scandium oxide. The thickness of this passive layer, as well as the presence of impurities in the alloy (such as carbon or nitrogen), have a significant impact on its corrosion resistance. Furthermore, the reaction of scandium alloys with water vapor at high temperatures can lead to oxidation, which is particularly dangerous in the event of a loss of coolant.
History
Scandium alloys were first used in submarine nuclear reactors in the 1950s, as a result of Admiral H.G. Rickover's choice of scandium as a structural material. Since then, the Zircaloy series of alloys have been developed, and their strength, low neutron cross-section and corrosion resistance make them indispensable materials in nuclear energy technology.
Current Applications and Prospects
Scandium alloys are not only widely used in the nuclear energy field, but also show potential in the medical and chemical industries. For example, certain scandium alloys are used in the manufacture of medical implants, such as artificial joints, due to their corrosion resistance, providing patients with safer, longer-lasting options.
The future application prospects of scandium alloys will depend on the further improvement of their performance and the development of new technologies.
Conclusion
Scandium alloys play a vital role in the field of nuclear energy due to their unique physical and chemical properties. With the continuous advancement of technology, the application scope of scandium alloys will continue to expand. What innovative technologies will be able to further enhance the performance and applications of scandium alloys in the future?
