Abstract: This disclosure enables a creation of a detachable connection between a linear motor tubular armature and a vertical cylindrical rod of an actuator of a control and protection system of a nuclear reactor. Such configuration reduces a dose load on a member of personnel, as well as provides an increase in reliability of a coupling of the linear motor tubular armature and the vertical cylindrical rod in conditions of high temperature and radiation.

Abstract: A fast-neutron nuclear reactor fuel assembly having fuel rods. Each fuel rod has nuclear fuel disposed in a sealed housing in the form of a tubular steel shell and end parts. A steel spacer element is wound in a coil with a specific pitch on the outside surface of the shell and is fastened on the end parts. The spacer element is in the form of a metallic band twisted around its longitudinal axis. The width of said band is approximately equal to the minimum distance between adjacent fuel rods in the fuel assembly. A transverse cross-sectional area of the band is within a range from 0.10 to 0.50 times the area of a circle described around the width of the band.

Abstract: A method and apparatus for neutron radiography is provided for the examination of elongate radioactive items, primarily nuclear fuel elements, and also for the non-destructive testing of irradiated and non-irradiated objects in order to determine the internal structure and material composition thereof. The method and apparatus include placing an object under examination into a protective container. A detection system includes a rotatable limb with a mounting seat for securing neutron detectors in a diametric groove. The limb being mounted to be rotatable by a set angle about an axis parallel to the axis of the object under examination and having a semi-circular recess therein for the passage of an elongate object as the limb rotates by an angle ±?i relative to the direction of a neutron beam.

Abstract: The invention relates to means for protecting the environment from the consequences of fires complicated by a radiation factor. A composition for dust suppression and containment of radioactive products of combustion after a fire with a radiation factor has been extinguished comprises, as a surfactant, a mixture of an anionic, a non-ionic and an amphoteric surfactant, and has the following ratio of components: 3.0-7.0% by weight of an aqueous solution of polyvinyl alcohol (in terms of a mass fraction of dry product); 0.1-0.3% by weight of plasticizer; 11.0-29.0% by weight of surfactant; with water making up the remainder. The invention makes it possible to carry out dust suppression and containment of radioactive products of combustion which are formed on surfaces, including at elevated temperatures, after a fire has been extinguished.

Abstract: The invention relates to the field of thermonuclear fusion and can be used in devices for electrically connecting components situated inside a nuclear fusion reactor chamber to the vacuum vessel of the reactor. A device for electrically connecting components situated inside a nuclear fusion reactor chamber to the vacuum vessel of the reactor comprises two identical stacks of electrically conductive plates. The electrically conductive plates are in the shape of a symmetrical wave having at least one full period. The plates in a stack are nested one inside another and are connected to flanges for attachment to a component situated inside the chamber and to the vacuum vessel. The stacks of electrically conductive plates are mounted with mirror symmetry about a line that passes through the centers of symmetry of the flanges.

Abstract: The method of launching natural circulation of the liquid metal coolant in the heat sink circuit of the fast neutron nuclear reactor without connection to the main heat source (first circuit heat sink) and without using pumping equipment, but only as a result of electric heating of the downing and lifting sections of the heat sink circuit to the specified temperatures and, as a consequence, the occurring difference in the densities of the coolant on the lifting and downing sections of the heat sink circuit.

Abstract: A thermonuclear reactor is provided having a vacuum casing and blanket modules connected thereto with flexible supports. The flexible supports are formed from a material with high electrical conductivity. Each flexible support is secured at one end on the vacuum casing and at the other end on a blanket module, the two secured ends of each flexible support face the blanket module. The flexible support is formed from two hollow cylindrical elements placed one in the other and perforated by longitudinal slots in a part free from mountings. The ends of the hollow cylindrical elements opposite the secured ends are connected electrically and mechanically. The technical result consists in diverting eddy currents away from a blanket module of a thermonuclear reactor and simultaneously eliminating electrical connectors from the composition of a blanket and reducing bunching on a blanket module side facing the vacuum casing.

Abstract: A fuel assembly design for nuclear reactors that is used in fast neutron reactor cores to provide more reliable spacing of a fuel element bundle in a fuel assembly and reduced local stress in the cladding of the fuel elements in the region where the elements are in contact with spacing elements. The fuel assembly has a top nozzle and a bottom nozzle which are connected to one another by a jacket. A bundle of rod-type fuel is elements arranged in the fuel assembly with the aid of a grid and spiral spacer elements wrapped around the cladding of each fuel element. At least the peripheral fuel elements in the bundle are provided with spacer elements in the form of thin-walled tubes with longitudinal through slots, wherein the elements have a substantially oval cross section in the regions where they are in contact with the jacket.

Abstract: A device for determining the parameters of strip-type superconductors includes a generator, a generator frequency-setting element, an inductance coil connected to the generator, a receiver, a receiver frequency-setting element, and an inductance coil connected to the receiver. The generator and receiver frequency-setting elements are same type narrow-band elements. The pass bands of the generator and receiver frequency-setting elements coincide through at least half of the bandwidth of the frequency-setting element having a narrower band pass width. The generator and receiver inductance coils are arranged with a gap between the same, making it possible for a strip-type superconductor to be placed between the inductance coils. The device is provided with a temperature sensor comprising a thermistor in contact with the superconductor. The device enables highly accurate and reproducible measurement results.

Abstract: The invention relates to the field of thermonuclear fusion and can be used in devices for electrically connecting internal elements of the reactor chamber to the vacuum vessel of the nuclear fusion reactor. The present device for electrically connecting elements inside the chamber of a reactor to the vacuum vessel of the nuclear fusion reactor comprises lamellar electrically conductive elements with surface portions oriented in different directions, said elements being stacked between flanges. The device is made as an integral unit, where profiled slots are formed with connecting walls therebetween. The connecting walls constitute the electrically conductive elements and have profiled sections of an increased thickness between the differently oriented surface portions at transition areas to the flanges provided at the end parts of the integral unit.

Abstract: The invention relates to nuclear reactor protection systems and can be used when building nuclear reactors, in particular, the fast neutron reactors. The Technical result of the invention consists in the expansion of 5 functional capabilities of the negative reactivity passive insertion device by securing its reliable actuation in various emergency conditions. The device has two vessels located in a common enclosure one under another with a ring-shape hollow space between the vessels and the enclosure to let the heat carrier flow. Fuel elements are located in the ring-shape hollow space, as well as the tooling for the heat carrier flow formation to cool the fuel elements and heat the upper vessel. The upper vessel is located above the reactor core and is divided with an internal partition wall to the central cylindrical and ring-shape hollow spaces. The partition wall has low thermal conductivity in the transverse direction.

Abstract: The proposed invention relates to processes for extracting and concentrating radionuclides and can be used in radiochemical technologies when treating liquid radioactive waste. The method for isolating americium from liquid radioactive waste and for separating americium from rare earth elements in a single extraction cycle involves joint extraction of americium and rare earth elements from a nitric acid radioactive solution with a neutral solution of an organic extraction agent in a polar fluorinated solvent; washing an obtained organic phase saturated with metals; and selective back extraction of americium, wherein the extraction agent for joint extraction is N,N,N?,N?-tetraalkylamide of diglycolic acid, and a solution for back extraction is a composition of 5-20 g/l of a complexone, 5-60 g/l of a nitrogen-containing organic acid and 60-240 g/l of a salting-out agent.

Abstract: The invention relates to the field of thermonuclear fusion and can be used for securing a blanket module to a vacuum vessel of a fusion reactor. The connecting device comprises a flexible support in the form of rods mounted between an upper flange having a concave spherical surface and a lower flange; a displacement compensator mounted on the upper flange; and a male-threaded locknut. The displacement compensator is fixedly connected to the blanket module and comprises a locking screw and a supporting sleeve, which are pivotally interconnected, a spacer sleeve, and a coupling sleeve with a spherical protuberance. The spacer sleeve is movably connected to the locking screw and pivotally connected to the upper flange of the flexible support and to the spherical protuberance of the coupling sleeve. The coupling sleeve is fixedly connected to a stop surface of the locknut.

Abstract: The invention relates to nuclear power and can be used in the manufacture of fuel elements for nuclear reactors. Embodiments of a welded joint between a fuel element casing and a plug comprised of high-chromium steel are proposed, providing for increased durability of the sealing of nuclear reactor fuel elements as a result of the formation of a high quality welded joint between the casing and the plug without the need for subsequent heat treatment of the weld seam, which simplifies the manufacturing process. This is achieved through the formation of a ferrite phase in the metal of the seam by adjusting the structure of a joint between the casing and the plug of ferrite-martensite and ferrite steels in various combinations and by keeping the necessary ranges of the size ratios to ensure the formation of the aforesaid phase.

Abstract: The invention relates to nuclear power and can be used in manufacturing of fuel elements for nuclear reactors. A method of sealing nuclear reactor fuel elements is proposed comprising welding one end of a casing with a first plug, loading the fuel element with fuel, and welding a second plug to another end of the casing. The casing is of a high-chromium ferrite-martensite steel and the plugs are of a ferrite steel. Argon arc welding is carried out at a volume ratio of the materials of the casing and the plugs contributing to formation of the metal of the weld seam which allows formation of a ferrite phase in said metal, wherein the ratio is: V1/V2?0.18, where V1 is the volume of ferrite material and V2 is the volume of ferrite-martensite material. Argon arc welding is carried out at a current of 14-20 A, a speed of 12-15 m/h, an arc voltage of 9-10 V and an argon flow rate of 7-8 l/min. This method provides for the desired quality of the welded joins and simplifies the fuel element manufacturing process.

Abstract: Steam generators are in the form of tubular heat exchangers in which molten lead coolant flows within the pipes, while the water-steam flows in a space between the pipes, the steam generators are arranged in separate boxes and communicate with the reactor cavity by means of circulation conduits for raising and discharging the lead coolant, the steam generators and most of the circulation conduits and are arranged higher than the level of the lead coolant within the reactor cavity, and the circulation pumps are arranged within the reactor cavity on the circulation conduits and for raising the “hot” lead coolant, and a technical means is provided for ensuring natural circulation of the lead coolant through the reactor core when the circulation pumps are switched off. The specific volume of lead coolant per unit of power of the reactor is reduced and the safety of the reactor is increased.

Abstract: An active zone includes a homogeneous uranium-plutonium nitride fuel, the mass fraction of which is a minimum 0.305, and consists of central, intermediate and peripheral parts which form fuel assemblies comprising fuel elements with geometrically identical shells but differing heights. The radial distribution of the fuel across the volume of the active zone has a stepped shape. The radius of the central part is from 0.4 to 0.5 of the effective active zone radius, while the height of the fuel column in the fuel elements in the central part is from 0.5 to 0.8 of the height of the fuel column in the peripheral part. The heights of the fuel columns forming a stepped intermediate part for diameters ranging from 0.5 to 0.85 of the effective active zone diameter are within the range from 0.55 to 0.9 of the height of the fuel column in the peripheral part.