An analysis of existing and possible designs of high-temperature gas-cooled reactor installations has shed light on the critical elements determining the reactor’s efficiency and reliability; it required determination of approaches to the development and theoretical and experimental substantiation of solutions for such critical units. Among the problems requiring a separate investigation in the development of the concept for the reactor are the selection and validation of the solutions for the cooling system of the reactor’s pressure vessel, which is one of the nuclear and radiation safety barriers. The selection and validation were accomplished using modern software tools, tests, and tests and experimental studies were performed on prototypes. The proposed and substantiated, both computationally and experimentally, scheme of the low-temperature leg that cools the units of the reactor vessel that are sensitive to high temperatures made it possible to reduce the temperature gradient and increase the permissible stresses on the reactor pressure vessel.

The main directions of development of small-scale energy generation are shown and a list of developed small-scale energy projects (SNPP) is given. The main results of work performed in 2019–2020 on the conceptual design of SNPP based on a developed reactor installation are presented. The key directions of modernization of a prototype reactor installation are indicated, and a plant concept and individual design solutions are described. The planning and architectural solutions for the main building and the site of the nuclear power plant as a whole are presented. A preliminary assessment of the technical and economic metrics of the object being created has been made. The possibility and feasibility of modernizing the SHELF installation in order to increase the commercial attractiveness of the project are shown.

The concept of a small gas-cooled reactor for the Brayton cycle using reactor technologies, design solutions, and existing experience of NIKIET is proposed. The concept is based on the optimal use of existing materials in the design and implements the principles of universality, modularity, and compactness. Variants of the reactor design, design of the transport lock system, cooling channel of the critical components of the reactor vessel, and radiation protection are presented.

The conception of a transportable small power plant based on a high-temperature gas-cooled nuclear reactor and a gas-turbine plant for supplying heat and electricity to settlements in the Far North and Siberia is presented. An open-loop energy conversion scheme with a Brayton cycle making possible quick start-up and leveling the fluctuations due to routine maintenance work or single failure of the main equipment, in the power delivery to the consumer is studied.

A method of increasing the intensity of electron Bremsstrahlung by means of multiple passage of an electron beam through a conversion target placed in a magnetic field is described. After each passage through the conversion target, the diverging beam of electrons is focused in magnets with special pole pieces. To study the formation of the Bremsstrahlung flux the characteristics of the Bremsstrahlung of the 2–8 MeV electrons were calculated for aluminum, tin and tungsten targets of different thickness. This made it possible to choose the optimal target material and thickness.

The description of an electron bremsstrahlung characteristics calculation model for a multi-layer conversion target, placed in a hyperbolic magnetic field, is given. The bremsstrahlung characteristics from 10-layer copper target at electron energy up to 300 MeV were obtained. The thickness of each layer is equal to 0,05 radiation length. Quadrupole magnetic triplets are located between layers. It is shown, that the bremsstrahlung source intensity with use of suggested magnetic system grows almost in 1,8 times at registration cone equal to 1 O. For the numerical decision of equation of the charged particles movement in the magnetic field, given by a magnet, the linear difference method for a Koshi task approximation for first order ordinary differential equations system was used.

The description of an electron bremsstrahlung characteristics calculation model for a multi-layer conversion target, placed in a hyperbolic magnetic field, is given. The bremsstrahlung characteristics from 10-layer copper target at electron energy up to 300 MeV were obtained. The thickness of each layer is equal to 0,05 radiation length. Quadrupole magnetic triplets are located between layers. It is shown, that the bremsstrahlung source intensity with use of suggested magnetic system grows almost in 1,8 times at registration cone equal to 1 O . For the numerical decision of equation of the charged particles movement in the magnetic field, given by a magnet, the linear difference method for a Koshi task approximation for first order ordinary differential equations system was used.

Plasma heating and spraying of different materials are considered.Data are given on the energy balance of plasma jets.1t is shown that, using plasma spraying, one can produce coatings and composite materials.Physicochemical processes causing formation of strong bonds between coating and substrate are considered.Experimental investigations of the rate of increase of bond strength for melted particles which are being sprayed on the polished surface of specimens have shown that the main stage in this process is chemical interaction of a particle and the substrate.Data on interaction of 80 pairs of materials are given.These are activated processes, and the activation may be due to heating of the substrate and overheating of the sprayed particles.The effects of different parameters both on the type of reactions and their kinetics are analysed.The activation energy for the formation of a strong bond between metals by• spraying is approximately .half the bond energy of atoms in the metallattice of a substrate.