[en] The calculational analysis of indexes for different versions of the multicomponent nuclear power (NP) model using various types of breeders is conducted. Three main versions of the developing NP with reactors of different types are considered: a) without the NP system additional feeding from an external source, b) with the NP system additional feeding with fuel from a special breeder not supplying electric energy to the system, c) with the NP system additional feeding with nuclear fuel from a breeder which supplies electric energy to the system as well. The analysis of relations obtained shows that in the closed-in- fuel NP model under consideration there are practically no sufficient realistic conditions for use of the special secondary nuclear fuel breeders without producing parallel to the fuel also the energy for the system. One of the basic arguments which proves the necessity of alternative breeder development is the requirement of assuring the future NP applicable structure in which about 50-60% of energy should be generated by thermal reactors. Investigations show that fast BN-type reactors with impved fuel, for example, using metal fuel assure the possiro/ bility of the NP closed-in-fuel model development with the given part of NPPs with thermal reactors

[en] Methodological problems on analysis of FBR efficiency with metal fuel using uranium and thorium in uranium-plutonium and mixed fuel cycle are considered. The investigations carried out permit to confirm that transition to application of LMFBR with metal fuel when accumulating in thorium screens of uranium-233 designed for application in WWER thermal power reactors permits to realize fuel self-providing condition for multi-component general purpose nuclear power in the framework of mixed fuel cycle with combined application of uranium and thorium. 10 refs.; 7 tabs

No abstract available

[en] The initial characteristics of the breeders affect the doubling time and the structure of the two-component system. The parameters of the thermal reactor are fixed having the VVER-1000 water-moderated-water-cooled power reactor in mind. As an example a fast reactor with a thermal rating of 3000 MW operating on oxide fuel with a thermal stress Q of 300 to 800 kW/liter in the core is considered. The results illustrate the fact that in a two-component nuclear power (NP) system in a state of dynamic equilibrium the optimal breeder should have different core design parameters than does a reactor optimized according to doubling time in a system consisting of only breeder reactors of one type. 3 refs

[en] The results are described of an investigation of another concept, which makes it possible to use metal fuel in the core of a fast reactor under temperature conditions close to previously employed conditions. It follows that fast reactors, in which oxide and metal fuels are used in combination, have an increased specific load and an increased breeding coefficient relative to fast reactors with oxide fuel; this reactor type allows faster rates in the development of the entire nuclear energy generation balanced in regard to fuel. The combined use of mixed oxide and metal fuels requires additional research on the possible operation of fuel elements in such a core

[en] A study of the characteristics of fast power reactors using combined oxide and metal fuels is reported. Two core fuel arrangements are considered. In the first, oxide fuel assemblies and metallic fuel assemblies are located in the core in some particular optimum proportion, i.e. one possible version of the traditional heterogeneous concept with some initial enrichment of the metallic uranium fuel is considered. In this arrangement, the ''metallic'' assemblies have to satisfy requirements in respect of maximum burnup (<=1.5% FIMA), initial enrichment (0-2%) and linear load (qsub(e)<=300 W/cm). In the other variant, the metallic and oxide fuels are placed in individual assemblies which make up the core. In this arrangement the fuel elements containing metallic fuel are located only on the side where the ''cold'' coolant enters the core whereas the oxide fuel is located in separate elements or in common elements with metallic fuel on the side where the ''hot'' coolant leaves the reactor. The relatively low coolant temperature (tsub(coolant)<=460⁰C) in the region where the metallic fuel is located ensures a sufficiently high linear load (qsub(e) approximately 500 W/cm) with moderate temperatures at the metallic fuel centre (tsup(max)sub(centre)<=650⁰C) and in the cladding (tsup(max)sub(clad)<=550⁰C). It is shown that fast reactors using oxide and metallic fuels in combination have substantially higher breeding ratio and greater specific accumulation of new fuel. The higher internal breeding ratio of the core helps to stabilize reactivity during runs between fuel loadings and the sodium-void coefficient is also improved. (author)

[en] Problems of using metal fuel in fast reactor (FR) core are discussed Results are given of the calculation of two-dimentional (R-Z) FR version having a composed core with the combined usage of oxide and metal fuels having parameters close to optimal from the point of view of fuel breeding rate, an oxide subzone having increased enrichment and a decreased proper conversion ratio. A reactor is considered where metallic fuel elements are placed from the side of ''cold'' coolant inlet (400-480 deg C), and oxide fuel elements - in the region where the coolant has a higher temperature (500-560 deg C). It is shown that the new fuel breeding rate in such a reactor can be increased by 20-30% as compared with an oxide fuel reactor. Growth of the total conversion ratio is mainly stipulated with the increase of the inner conversion ratio of the core (CRC) which is important not only from the point of view of nuclear fuel breeding rate but also the optimization of the mode of powerful fast reactor operation with provision for the change in reactivity in the process of its continuous operation. The fact, that the core version under investigation has a CRC value slightly exceeding unit, stipulates considerably less reactivity change as compared with the oxide version in the process of the reactor operation and permits at a constant reactor control system power to significantly increase the time between reloadings and, therefore, to increase the NPP load factor which is of great importance both from the point of view of economy and the improvement of operation conditions as well as of reactor operation reliability. It is concluded on the base of the analysis of the results obtained that FRs with the combined usage of oxide and metal fuels having an increased specific load and increased conversion ratio as compared with the oxide fuel FRs provide a higher rate of development of the whole nuclear power balanced with respect to the fuel

[en] The analysis of activities carried out in this country and abroad on a complex solution of principal problems of nuclear power advance. Demonstration of the potentiality of the above problems solution on the basis of conventional reactor plant development (light water cooled reactors and BN-type fast reactors) within the framework of nuclear fuel cycle using uranium-235, plutonium and uranium-233. 28 refs.; 1 fig.; 8 tabs

[en] The paper presents a brief analysis of the domestic and foreign experience from the development of the only type of fast breeder reactor brought to a commercial level, namely, the liquid-metal cooled fast breeder reactor. It is concluded that the main problems concerning safety, ecology and economics of breeder reactors could be overcome by developing inherently safe fast reactors with metallic fuel which produce secondary fuel in the form of uranium 233. (orig.)

[en] The approach to a possible solution of the problem of peaceful utilization of weapon-grade plutonium released in the result of nuclear disarmament in Russia is given in the repot. As the most safe, ecologically acceptable and economically effective way of the plutonium utilization is the usage of such plutonium as a fuel for atomic power station. It is proposed to decide the problem on the basis of BN-600 and BN-800 reactors. In the approach, thorium could be used as a fertile material. The secondary nuclear fuel U-233 is expedient to use in light-water reactors of new generation. (author)