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MOSCOW, March 24 In 2022, Rosatom State Corporation specialists completed all the tasks set in the development of new materials for advanced energy systems — in In particular, samples of metals for reactor plants necessary for the development of nuclear energy have been obtained, said Alexei Dub, First Deputy General Director of JSC Science and Innovations (the management company of the scientific division of Rosatom).
“The most important thing is that in 2022, within the framework of the program “Development of Engineering, Technologies and Scientific Research in the Field of the Use of Atomic Energy in the Russian Federation” (RTTN), all planned tasks were completed, we are progressively moving forward in various directions,” he noted.
Materials for new installations
«One of the main tasks of the RTTN program was to ensure technological independence and development — not only for the nuclear industry, but also for other industries, this task is especially relevant now,» said Dub.
According to him, the specialists of the Russian nuclear industry are fulfilling their mission to create new materials for promising devices.
«The lifetime of a particular plant determines the superiority of the industry over competitors. Therefore, knowing how different materials behave at extreme pressures and temperatures, under given service conditions, is very important for designers to understand how to create new plants,» — explained the source of the agency.
“From this point of view, in 2022 we made a very significant step forward in creating an accelerated testing technique that allows us not only to qualitatively, but quantitatively evaluate the properties of a material in terms of such important indicators for the nuclear industry as swelling, susceptibility to high-temperature radiation embrittlement, resistance to brittle destruction, stress corrosion cracking,» the source added.
Last year, one of the significant achievements of RTTN was the production of stepped forgings from new steels for advanced reactor plants VVER-S and VVER-SKD, Dub said.
«A metal was obtained that is distinguished both by its purity and significant strength. The so-called thermal and radiation embrittlement for such a metal manifests itself to a much lesser extent than before,» he said.
Perspective materials will make it possible to provide projects of future generations of reactors with highly reliable and high-life vessels. In particular, increasing the stability of the properties of the materials of the reactor vessel, mastering and improving the technology for manufacturing long shells to ensure the possibility of removing welds from the irradiation zone is relevant for the promising VVER-S reactor (pressure-controlled water-cooled power reactor).
Spectral control will make it possible to improve the efficiency of using nuclear «fuel» in reactors, which is important from the point of view of the implementation in Russia of the strategy of two-component nuclear power engineering, in which «fast» reactors will be paired with currently traditional thermal neutron reactors.
In VVER-SKD reactors, at the so-called supercritical pressure, the distinction between liquid and vapor disappears, and water is in an intermediate state. According to experts, the transition to supercritical parameters will increase the efficiency of NPP power units up to 45%, reduce the specific capital costs for their construction while ensuring high safety.
About promising fuel
“I must also say that we have made significant progress on such a material as silicon carbide. It will be used to create the so-called tolerant nuclear fuel. In 2022, silicon carbide samples were obtained with a very low oxygen content as an impurity, which is extremely important for work of this material in nuclear reactors.In fact, a quasi-viscous state of silicon carbide was ensured — in other words, special composite samples from it demonstrate not only strength, but also elasticity. meet the necessary requirements for the manufacture of shells of tolerant fuel,» said Dub.
Academician Bochvar High-Technological Research Institute of Inorganic Materials (JSC VNIINM, an enterprise of the Rosatom fuel company TVEL) is leading an industry project to create fuel element claddings from a composite material based on silicon carbide.
The use of accident tolerant fuel is believed to significantly improve the safety and efficiency of nuclear power plants. The world is actively working on the creation of such fuel, resistant to accidents with loss of coolant, when the supply of cooling water to the core of a nuclear reactor is stopped, which leads to overheating of nuclear fuel. As a result of an increase in the temperature of zirconium shells of fuel elements, the so-called zirconium vapor reaction occurs, accompanied by the release of an additional large amount of heat and hydrogen, the explosion of which can lead to the destruction of nuclear power unit structures and the release of radioactive substances into the environment.
One of the possible solutions to this problem is based on replacing zirconium with materials in which the reaction with steam proceeds with a lower energy release and less hydrogen is produced. Silicon carbide (carborundum) is one of these materials.
Research Institute «LUCH» in Podolsk near Moscow (JSC «NII NPO «LUCH», part of the scientific division of «Rosatom» ) is developing a technology for obtaining products of complex shape from silicon carbide with dimensions up to 900 millimeters.
“In terms of silicon carbide, we are not only at the world level, but we are even faster than our foreign competitors,” Dub added.
Reactor-«scavenger»
A big result in the framework of the RTTN program in 2022 was the completion of a draft design of a research liquid-salt nuclear reactor (IZhSR), which is scheduled to be built at the enterprise » Rosatom» «Mining and Chemical Combine» (FGUP «GCC», Zheleznogorsk, Krasnoyarsk Territory).
«This is a truly significant result, one of the key results in the IZhSR project. Now it becomes possible to move on to justifying investments in the reactor project and assessing its impact on the environment,» Dub explained.
Ensuring economic efficiency and improving the environmental safety of nuclear power is largely tied to the management of spent nuclear fuel. It is necessary to solve the problem of the so-called minor actinides — long-lived radioactive isotopes of transuranium chemical elements, mainly americium and curium. They make the main contribution to the high radioactivity of the waste remaining after the processing of nuclear fuel. Minor actinides can be effectively recycled using transmutation — «burning» in nuclear reactors or with the help of accelerators.
For these purposes, it is proposed to use liquid-salt nuclear reactors on melts of radioactive substances in metal fluorides. As experts explain, such installations will have a number of advantages, including increased safety, since severe accidents cannot occur on them due to technological features. In addition, such reactors do not require the manufacture of conventional fuel cells.
«The task is to find materials that would have a resource that ensures the safety of such a reactor so that the liquid-salt melt, the operating temperature of which will be 600-700 degrees, would not escape into the environment. We conducted complex experiments to substantiate the behavior of materials in the conditions of salts of two types, different in their reactivity. Quite satisfactory results have been obtained in terms of the rate of general and intergranular corrosion, making it possible to proceed to engineering work on the creation of a reactor plant, «Dub said.
An important task is to control the redox potential in molten salt, so Rosatom specialists and partners from the Ural Branch of the Russian Academy of Sciences are creating experimental cells that allow such control, he added.
«In 2023, we must start a project to create a research loop at the SM-3 reactor at the Research Institute of Atomic Reactors in Dimitrovgrad (JSC «SSC RIAR», part of the scientific division of «Rosatom»), in order to assemble it in practice in 2024 «, said Dub. A research loop is actually an experimental facility based on one or more channels of a research nuclear reactor.
3D printing
Aleksey Dub called the development of 3D printing technologies (additive technologies) another important area of work for Rosatom scientists.
«We are working in seven different areas — printing products for nuclear energy, for example, for low-power nuclear power plants, for space and other industries. Moreover, these works are methodically lined up in exactly the same way — they immediately create target products at new installations,» he said. agency interlocutor.
«For example, for products made of carbon materials, the Research Institute of Graphite-Based Structural Materials (JSC NIIGrafit, part of the scientific division of Rosatom») makes a printer that allows you to simultaneously provide both continuous and dispersed reinforcement of the matrix with carbon or glass fiber. This allows you to achieve very good properties,» added Oak.
For the needs of the aviation industry, a large installation is being created, on which it is possible to make honeycomb panels from titanium wire with dimensions of more than 2 meters to obtain load-bearing products. «This year we will already have pilot products,» said Dub.
Work is underway to ensure fundamental science.
«We are moving in the direction of providing the possibility for scientists of the Joint Institute for Nuclear Research (JINR) in Dubna to obtain 119 and 120 elements of the periodic table,» said Dub.
JINR plans to conduct a series of experiments on the synthesis of elements 119 and 120 by irradiating targets containing berkelium-249 and californium-251 with calcium-48 ions. To develop their milligram amount, RIAR will conduct reactor irradiation of a gram amount of heavy curium isotopes in targets. The project involves the Russian Federal Nuclear Center — All-Russian Research Institute of Experimental Physics (FSUE «RFNC-VNIIEF», Sarov, Nizhny Novgorod Region).
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