MOSCOW, June 21 Specialists from the Vernadsky Institute of Geochemistry and Analytical Chemistry (GEOKHI) of the Russian Academy of Sciences have proposed a new, integrated approach to the management of spent nuclear fuel (SNF), which, according to the developers, will help the development of domestic nuclear energy , reported the Ministry of Science and Higher Education of the Russian Federation.
The issues of reprocessing fuel that has «expired» its life in nuclear reactors are becoming especially relevant in connection with the development in Russia of technologies for a closed nuclear fuel cycle (CFFC). The idea is to «pair» the operation of traditional VVER power reactors running on thermal neutrons with fast neutron reactors. The CNFC will expand the reproduction of nuclear «fuel» and significantly increase the fuel base of nuclear power, eliminating the need to extract natural uranium in large volumes.
< /span>
It will also be possible to reduce the amount and biological hazard of radioactive waste remaining after the processing of spent spent nuclear fuel — the most dangerous substances, the so-called minor actinides (americium, curium), are planned to be «burned out» in fast neutron reactors. In this way it will be possible, as nuclear experts figuratively say, to «take out two key thorns» in the current nuclear power industry, connected with the limited reserves of natural uranium and the deferred problem of spent nuclear fuel.
SNF reprocessing is a key stage necessary for closing the nuclear fuel cycle.
GEOKHI researchers proposed methods for isolating a group of so-called transplutonium and rare earth elements from waste, then separating americium from this group for its potential transmutation (“burning out” in reactors), and also developed new materials for the conservation of radionuclides. The complex methodology for reprocessing spent fuel, which scientists are working on, will be in demand in the context of the transition of the Russian nuclear power industry to a closed nuclear fuel cycle.
«
“The strategy for the development of the nuclear industry in Russia is to close the nuclear fuel cycle in a system of two-component nuclear energy, that is, with a balanced use of thermal and fast neutron reactors. It is possible to achieve this goal only with the introduction of spent nuclear fuel reprocessing technology, which will be distinguished by efficiency, radiation safety and satisfactory economic indicators,” explained Sergey Vinokurov, Deputy Director for Research at GEOKHI.
According to the scientist, the prospects for a closed nuclear fuel cycle in Russia are associated not only with the regeneration of uranium and plutonium, but also with the deep fractionation of the resulting radionuclides, that is, their division into separate fractions — for example, according to their half-life or according to their degree of toxicity. Among other promising areas for the development of a closed cycle is the management of radioactive waste by conditioning and incorporation into solid stable matrices (for example, glass or mineral-like materials) for environmentally safe disposal.
GEOKHI researchers are developing a technology for reprocessing 4th generation spent nuclear fuel, which differs from the previous ones by focusing on a significant reduction in the amount of radioactive waste for deep disposal.
«Our task is to optimize the processing stages and create a single technological scheme. Some well-known and industrially proven solutions, in our opinion, require practically no intervention, for example, the dissolution stage or head extraction when using an extraction system well known in the industry. At the same time, based on As a result of our work, we proposed new methods for isolating a group of transplutonium and rare earth elements from waste, then separating americium from this group for its potential transmutation, and developed new materials for the conservation of radionuclides,” Vinokurov said.
The integrated SNF reprocessing technology that GEOKHI researchers are working on is focused on new-generation radiochemical plants, however, some of the developed methods can already be used at specialized enterprises — for example, new phosphate materials for radioactive waste.
According to the scientists, Rosatom State Corporation showed interest in their developments. The scientific team plans to soon conduct experimental tests of the proposed technological solutions.