Abstract: Systems for controlling and protecting nuclear reactors. A drive of an emergency safety rod of a nuclear reactor includes an electric drive, a reduction gear, and a rack-and-pinion gear. The electric drive contains a contactless electric motor based on permanent magnets, which is installed in the housing of the electric drive with a motor rotor position sensor, and a reduction gear for changing the rate of rotation of the electric drive. A toothed rack is installed along the axis of the rack-and-pinion gear in order to provide for the reciprocating motion of a system absorber rod connected thereto. A toothed electromagnetic clutch having a contactless current supply is installed on an inner shaft of the rack-and-pinion gear, enabling the rigid and simultaneous mechanical coupling of half-couplings, and the drive contains a reverse-motion coupling, a rack-separation spring and toothed rack position sensors.

Abstract: A method for guaranteeing fast reactor core subcriticality under conditions of uncertainty involves, after assembling the reactor core, conducting physical measurements of reactor core subcriticality and comparing the obtained characteristics with design values; then, if there is a discrepancy between the values of the obtained characteristics and the design values, installing adjustable reactivity rods in the reactor at the level of a fuel portion of the reactor core, wherein the level of boron-B10 isotope enrichment of the adjustable reactivity rods is selected to be higher than the level of boron-B10 isotope enrichment of compensating rods of the reactor core. The technical result consists in improving the operating conditions of absorbing elements of a compensating group of rods, eliminating the need for increasing the movement thereof, simplifying monitoring technologies used during production, and simplifying the algorithm for safe reactor control.

Abstract: The invention relates to nuclear physics, and specifically to reactor fuel elements and units thereof, and particularly to the composition of solid ceramic fuel elements based on uranium dioxide, intended for and exhibiting characteristics for being used in variously-purposed nuclear reactors. The result consists in a more reliable, special structure and a simple composition of uranium dioxide without heterogeneous fuel pellet additives, approaching the characteristics of a monocrystal having enhanced, and specifically exceeding reference data, thermal conductivity as temperature increases, and a simple production method thereof. The result is achieved in that pores of between 1 and 5 microns in size are distributed along the perimeters of grains in the micro-structure of each metal cluster in a nuclear fuel pellet, and in that located within the grains are pores which are predominantly nano-sized. In addition, the metal clusters comprise between 0.01 and 1.0 percent by mass.

Abstract: A method for the inner-contour passivation of steel surfaces of a nuclear reactor consists in filling a first contour of a nuclear reactor with a liquid metal coolant, introducing a reagent into the liquid metal coolant, said reagent interacting with the material of elements of the first contour, forming a protective film, and heating the liquid metal coolant, having the reagent introduced therein, to a temperature allowing for conditions for forming the protective film. The liquid metal coolant having the reagent introduced therein is kept at said temperature until a continuous protective film is formed on the surface of the material of the elements of the first contour. The liquid metal coolant having reagent introduced therein is heated by means of the friction thereof against rotating vanes of a vane pump, which is submerged in the liquid metal coolant.

Abstract: The invention relates to the field of nuclear technology, and specifically to a method for the in situ passivation of steel surfaces. The method consists in installing, in a position intended for a regular core, a core simulator in the form of a model of the core, which models the shape thereof, the relative position of the core components, and also the mass characteristics thereof; next, the reactor is filled with a heavy liquid metal heat transfer medium, the heat transfer medium is heated to a temperature which provides for the conditions of passivation, and in situ passivation is carried out in two stages, the first of which includes an isothermal passivation mode in conformity with the conditions determined for this stage, and the second mode includes non-isothermal passivation, which is carried out under different conditions, after which the core simulator is removed and the regular core is installed in the place thereof.

Abstract: A method for the inner-contour passivation of steel surfaces of a nuclear reactor consists in filling a first contour of a nuclear reactor with a liquid metal coolant, introducing a reagent into the liquid metal coolant, said reagent interacting with the material of elements of the first contour, forming a protective film, and heating the liquid metal coolant, having the reagent introduced therein, to a temperature allowing for conditions for forming the protective film. The liquid metal coolant having the reagent introduced therein is kept at said temperature until a continuous protective film is formed on the surface of the material of the elements of the first contour. The liquid metal coolant having reagent introduced therein is heated by means of the friction thereof against rotating vanes of a vane pump, which is submerged in the liquid metal coolant.

Abstract: The invention relates to the field of nuclear technology, and specifically to a method for the in situ passivation of steel surfaces. The method consists in installing, in a position intended for a regular core, a core simulator in the form of a model of the core, which models the shape thereof, the relative position of the core components, and also the mass characteristics thereof; next, the reactor is filled with a heavy liquid metal heat transfer medium, the heat transfer medium is heated to a temperature which provides for the conditions of passivation, and in situ passivation is carried out in two stages, the first of which includes an isothermal passivation mode in conformity with the conditions determined for this stage, and the second mode includes non-isothermal passivation, which is carried out under different conditions, after which the core simulator is removed and the regular core is installed in the place thereof.

Abstract: A method for guaranteeing fast reactor core subcriticality under conditions of uncertainty involves, after assembling the reactor core, conducting physical measurements of reactor core subcriticality and comparing the obtained characteristics with design values; then, if there is a discrepancy between the values of the obtained characteristics and the design values, installing adjustable reactivity rods in the reactor at the level of a fuel portion of the reactor core, wherein the level of boron-B10 isotope enrichment of the adjustable reactivity rods is selected to be higher than the level of boron-B10 isotope enrichment of compensating rods of the reactor core. The technical result consists in improving the operating conditions of absorbing elements of a compensating group of rods, eliminating the need for increasing the movement thereof, simplifying monitoring technologies used during production, and simplifying the algorithm for safe reactor control.

Abstract: The invention relates to nuclear physics, and specifically to reactor fuel elements and units thereof, and particularly to the composition of solid ceramic fuel elements based on uranium dioxide, intended for and exhibiting characteristics for being used in variously-purposed nuclear reactors. The result consists in a more reliable, special structure and a simple composition of uranium dioxide without heterogeneous fuel pellet additives, approaching the characteristics of a monocrystal having enhanced, and specifically exceeding reference data, thermal conductivity as temperature increases, and a simple production method thereof. The result is achieved in that pores of between 1 and 5 microns in size are distributed along the perimeters of grains in the micro-structure of each metal cluster in a nuclear fuel pellet, and in that located within the grains are pores which are predominantly nano-sized. In addition, the metal clusters comprise between 0.01 and 1.0 percent by mass.

Abstract: The invention relates to the field of nuclear engineering and can be used in the manufacture of fuel rods and fuel assemblies for heavy liquid metal cooled reactors, and also in the manufacture of fuel rod simulators for use in irradiation devices designed to test the operability of real fuel assemblies. The present gadding of a fuel rod for a heavy liquid metal cooled reactor is in the form of a weldless tubular element h helically-coiled fins disposed on the outer surface of said element, which is made from a ferritic-martensitic chromium-silicon steel with a minimum ferrite grain size of 7 on the GOST 5639 scale, wherein each fin has an opening angle of from 22 to 40 (preferably from 30 to 40) and the cross-section of the fin is in the shape of a trapezoid with rounded corners at the top of the trapezoid and smooth corners at the base of the trapezoid. Also disclosed are a fuel rod comprising the above cladding, and a fuel assembly.