MEPhl National Research Nuclear University (Russia) Dec. 6, 2016
MEPhI scientists have figured out how the change of nanostructure of materials for energy reactors of the future will affect their plasticity, heat resistance and other important properties.
Currently, one of the most promising areas in nuclear power are the development of new fast reactors and the creation of a workable fusion reactor. The first will allow close the nuclear fuel cycle and make nuclear energy more environmentally friendly. If the second becomes possible, then in the future there will be a chance to produce energy in a brand new way. The most famous project is designed to bring the appearance of an energy fusion reactor – ITER (International Thermonuclear Experimental Reactor).
One difficulty in creating new energy devices is that they all suggest the presence of extreme conditions of use in the energy zone. Therefore, the materials to be used in the active areas of new reactors must meet extremely high demands. Being exposed to high temperatures and the flow of high-energy radiation, modern materials are rapidly degraded. Most of them can withstand strong irradiation dose, at which each atom in the material moves 80-90 times. For the energy of thermonuclear installations this parameter should be twice as much. This resistance of the materials in the area of use of energy determines the effectiveness and safety of a nuclear reactor.
MEPhI scientists consider it possible to solve this problem with the help of nanotechnology. Ferritic-martensitic steels based on Fe-Cr alloys and dispersion-hardened steel oxides are considered to be promising for future power plants. In their works, scientists managed to experimentally demonstrate the mechanisms of atomic-scale restructuring of these materials, as well as to show how redistribution of atoms happens, resulting in a significant increase in their fragility and loss of plasticity. The results of these studies have been published in the Journal of Nuclear Materials and Journal of Nuclear Materials and Energy.
It is known that the change of the nanostructure can fundamentally change the properties of the structural material. And, as a result, significantly reduce the time of operation of settings’ active zones, made of it. In some cases, scientists, on the contrary, succeed in picking up such nanostructured changes that significantly extend the capabilities of the products and provide them with unique properties, such as large heat resistance.
In their experiments, experts influenced in a different way the model alloys Fe-Cr and steels, dispersion-reinforced by oxides, and then recorded arising changes in the properties of materials on the nanoscale, using the atomic-probe tomography.
“In our studies, we have analyzed the state of nanoscale materials and adjustment under different impacts. We carried out the thermal aging, and then, using beams of metal ions, found that their effects might lead to the reducing of nanostructures,” – said Deputy Head of MEPhI department of physics of extreme states of matter of the Institute of nuclear physics and technologies Sergey Rogozhkin.
According to the scientist, research results can be used both when creating materials for ITER, and for the future energy systems. “The aim of the ITER is to demonstrate the efficiency of the concept of fusion reactor. Requirements to the materials at this stage are severe, but a fusion plant of the next generation will create even more extreme conditions, for work in which, in fact, fundamentally new materials have been developed, including those that we are now investigating, “- said the expert.