Assembly of welded joint of fuel element jacket with plug made of high-chromium steel (versions)
SUBSTANCE: welded assembly of fuel element comprises a jacket and a plug with collar made of high-chromium steel, connected by weld seam obtained by argon-arc welding.
EFFECT: increased reliability of sealing of the nuclear fuel elements due to obtaining of the high-quality welded joint of the jacket with plug without subsequent heat treatment of the weld seam, is achieved by forming of the ferritic phase in the weld metal by changing the design of the jacket-plug connection made of steel of ferritic-martensitic and ferritic classes in various combinations in accordance with required sizes of the assembly and weld seam elements.
4 cl, 4 dwg, 1 tbl, 4 ex
FIELD: physics, nuclear.
SUBSTANCE: invention relates to nuclear power, particularly to methods used in preparing charge mixture from a mixture of nuclear fuel powder and matrix material for moulding cermet rods of nuclear reactor fuel elements. Binding material is added to nuclear fuel powder with the following ratio of components: paraffin (7.5-32) wt %, wax (2-10) wt %, trichloroethylene - the balance. Powder particles are coated with a film of the binding material by drying before obtaining quick granules. The coated powder is mixed with powder of the matrix material. The mixture is stirred until obtaining conglomerated particles and excess powder of the matrix material is removed.
EFFECT: invention increases radiation stability of the fuel composition by reducing the probability of disintegration of the fuel particles.
FIELD: physics, nuclear.
SUBSTANCE: invention relates to nuclear power, particularly to the technology of making rods of fuel kernes of cermet fuel elements. The solder for sealing a rod workpiece of the fuel kernel of a cermet fuel element of a nuclear reactor consists of a mixture of copper and zirconium powder in ratio (0.17-0.25):(0.83-0.75), consolidated by an organic binder. The copper powder has the fraction of 10-50 mcm and is selected from a batch with a main fraction of 5-10 mcm, and the zirconium powder has the fraction of 50-100 mcm and is selected from a batch with a main fraction of 100-140 mcm.
EFFECT: invention increases output of workpieces with suitable sealing.
FIELD: power industry.
SUBSTANCE: device includes vacuum-treated housing with thermal insulation, removable hopper for dispersion fissile material, electric heater and two current leads; at that, electric heater is tubular and connected with one of its ends to current lead insulated from the housing, and on lower end of heater there fixed is spiral the free end of which is connected to shell; at that, the second current lead is connected to housing, and current circuit is closed with workpiece of the cover for dispersion fuel element, which is arranged on inner side.
EFFECT: simplifying the design and providing reliability.
FIELD: power industry.
SUBSTANCE: chamber pumping is performed until pressure is 10-2 mm Hg, pressure increase is recorded in the chamber at hydrogen evolution and increased pressure is maintained during 60 minutes. During this period, complete decomposition of zirconium hydride occurs, and hydrogen left in zirconium in the form of solid solution is removed at pressure decrease to 10-2 mm Hg.
EFFECT: reducing the time required for hydrogen stripping, increasing the process efficiency.
FIELD: power engineering.
SUBSTANCE: welded part of plug additionally contains mould flash in form of face at 45° to generatrix of surface of plug in its welded part. The face is located at (4÷6)·δ distance, where δ is thickness of cladding, from surface of cold contact of the welded part of the plug with the end of cladding. A transition part of the plug has cylinder and conic elements. Surface of the face is conjugated with surface of the cylinder element of the plug transition part, which in its turn is conjugated with surface of the conic element of the plug transition part through radius (0.7÷2)·δ. Angle between generatrix of surface of the cylinder element of the plug transition part and a base of the conic element of the plug transition part with bigger diametre is 45°, while distance from the base of the conic element of the plug with smaller diametre to surface of cold contact of the welded part of the plug with the end of cladding is equal to (8÷10)·δ.
EFFECT: increased reliability of fuel element operation, reduced expenditures for its production.
FIELD: power engineering.
SUBSTANCE: invention refers to manufacturing method of nuclear fuel elements and may be used in nuclear power engineering during manufacturing, using contact-butt welding of fuel elements and guide channels of rod type for fuel assemblies of nuclear power reactors. Method includes fixing of end of can (1) of fuel element installed with embedding in welding fixture (2), welding to at least one edge of can (1) of plug (6) by contact-butt welding with its simultaneous displacement inside can (1) on section warmed by welding current, and quality control of welding and stability of process of welded joint sealing. Edge of plug (6) end installed in welding fixture is fixed with respect to edge of welding fixture (2) at a specified position. During plug (6) displacement inside can (1), control of voltage value on section of secondary circuit of welding set, generated by welding fixture with fuel element can end located in it, is performed. Obtained values of voltage are compared to values of voltage specific to conditions of optimum warming of weldments at analogous position of can (1) edge in welding fixture, and according to difference of obtained values quality of welding and stability of sealing process is determined.
EFFECT: improvement of fuel elements quality.
2 cl, 2 dwg, 1 ex
FIELD: technological processes.
SUBSTANCE: invention is related to method for manufacturing of fuel element (FE) of nuclear reactor and may find application in nuclear engineering. Method includes fixation of its shell end in welding installation equipment, creation of atmosphere with specified composition and pulling pressure by means of vacuumising, filling with high pressure inertial gas with further sealing with plug using contact-upset welding for its welding into shell, and its diametre is more than internal diametre of shell, and monitoring of gas pressure under shell. Monitoring is realised directly in welding installation. For this purpose prior to vacuumising clearance is created between ends of shell and plug arranged in welding installation, and its value is measured at continuous measurement of gas pressure value. Value of clearance is first measured till filling of fuel element shell with gas, then after application of welding force. Afterwards produced results are compared, and permits for welding are issued, if difference in produced measurements corresponds to specified values.
EFFECT: invention provides for improved serviceability of fuel elements.
6 cl, 3 dwg
FIELD: welding works.
SUBSTANCE: invention is related to method of contact-butt welding of pipe with plug and may find application in manufacturing of rod fuel elements of nuclear plants. Method includes placement and fixation of pipe end with deepening in welding auxiliaries. Heating of pipe end and plug pressed by butts by welding current, at that plug has section welded into pipe wall, with diametre that is larger than internal one, but is less than external diametre of pipe, and further welding of plug into pipe wall with alternating speed of plug motion. Pipe end on section with length of 1.5-3 of pipe wall thickness is placed on section of welding auxiliaries, electric resistance of which is less than resistance of pipe section material in zone of welding. Heating of pipe end and plug pressed by butts by welding current is carried out due to contact resistance in butt between end of pipe and plug and area of welding current supply into pipe, which is arranged at the distance equal to 1.5-3 of pipe wall thickness from its end. Besides heating of welded parts in process of welding to arrange zone of thermal effect, which is common in length of welded joint with width in central part of welded joint, which is equal to 0.1-3 of pipe wall thickness.
EFFECT: simplified welding technology without deterioration of quality properties of welded joints.
2 cl, 3 dwg, 1 ex
FIELD: welding works.
SUBSTANCE: present invention pertains to welding, particularly to the method of sealing fuel elements of a nuclear reactor using contact-butt welding. Contact-butt welding is done on a fuel element casing with an end-cap, with maximum diametre less than the outer diametre of the casing, and greater than its inner diametre. The end of the casing is put into an expanding mounting with a depression. Welding is done with rate of increase of welding current to maximum value in the initial welding moment in the range of 1-3 kA/ms and its density in that period from 1.5 to 2.5 kA/mm2 with specific pressure of 35-80 kg/mm2 for a period of 10-60 ms. The end cap is moved deep into the casing at a distance of 2-5 times the thickness of the wall of the casing. If necessary, the displacement of the end cap can be limited due to restriction of the movement of the electrode linked to the actuator of the welding force of the installation.
EFFECT: invention can be used in nuclear power engineering.
2 cl, 9 dwg, 1 ex
FIELD: nuclear power engineering; fuel assemblies of pressurized-water reactors.
SUBSTANCE: proposed device designed for entrapping solid particles in fuel assembly has perforated plate which is undulatory in direction transversal to coolant flow. Mentioned plate in first design alternate of proposed device is saw-toothed in direction transversal to coolant flow. Mentioned plate in second design alternate of device is made in the form of concentric perforated truncated cones alternately installed with their vortices up and down. Mentioned plate in third design alternate of device is made in the form of concentric truncated pyramids alternately installed with their tops up and down.
EFFECT: enlarged total coolant flow section of device installed at fuel assembly inlet.
8 cl, 4 dwg
FIELD: physics, atomic power.
SUBSTANCE: invention relates to nuclear reactor fuel rods. Fuel rod cladding has an elliptical cross-section. Each nuclear fuel pellet along the longer axis of the cladding has a truncated elliptical shape, and the shorter axis of the pellet has the same length as the shorter axis of the cladding, minus the fitting gap j, wherein the difference in length of the longer axis of the cladding and the truncated longer axis of the pellet is much greater than said fitting gap j. The invention also relates to a method of making nuclear fuel pellets and a method of packing said pellets, which enables to form a fuel rod.
EFFECT: lower probability of deformation of fuel rod cladding and release of fission products into the coolant.
9 cl, 3 dwg
FIELD: machine building.
SUBSTANCE: procedure consists in immersion of tubular casing of fuel rod into water electrolytic medium containing particles of iron oxide and in covering it at least partially with layer of iron oxide. Also, particles of iron oxide are produced by anode oxidising iron containing working electrode.
EFFECT: increased corrosion resistance of treated rod and its increased service life.
7 cl, 1 dwg
FIELD: physics, nuclear.
SUBSTANCE: invention relates to nuclear power engineering and specifically to methods of making cermet rods of fuel cores of fuel elements of nuclear reactors for different purposes. A workpiece is put into a container. Working medium in form of solid glass is put into the container and the container with the workpiece and the working medium is heated to pressing temperature. The container is put into a press mould and moulding force is applied by increasing pressure of the working medium while moving the moulding die. In the proposed method the working medium is in form of a briquette. The briquette is placed at the bottom of the container. The workpiece is put on top of the briquette. The container with the workpiece and the working medium is heated outside the press mould until the workpiece is immersed in the working medium.
EFFECT: reduced probability of formation of voids, transfer of pressure onto the moulded workpiece becomes more uniform, increased output of the suitable products.
SUBSTANCE: invention is designed for increasing operation parametres and life cycle of active zone of a reactor due to the maximum fuel burnup, improved reliability and operation safety of maintenance of nuclear power stations. Fuel element can of a fast reactor with liquid metal heat carrier includes a metal tube of vanadium alloy with titanium, chrome and unavoidable impurities. External and internal tube surfaces are coated with stainless ferrite steel. Vanadium alloy components are taken at a given ratio. In particular, titanium to chrome ratio lies within 2.2 to 1.8 range. Between vanadium alloy and stainless ferrite steel a 6-8 mcm thick transition layer of solid solution of vanadium alloy with stainless ferrite steel is formed.
EFFECT: improved radiation, corrosion and heat resistance and mechanical properties of fuel element can in a fast reactor with liquid metal heat carrier.
3 cl, 5 dwg
FIELD: nuclear power engineering; nuclear reactor fuel microelements covered with four-layer shielding coating.
SUBSTANCE: proposed method involves sequential fluid-bed deposition of coating layers onto fuel microspheres. First low-density pyrocarbon layer is deposited by pyrolysis of acetylene and argon mixture of 50 volume percent concentration at temperature of 1450 °C. 85 - 95 % of second layer is deposited from high-density pyrocarbon by pyrolysis of acetylene and argon mixture of 40.0 - 43,0 volume percent concentration, and of propylene and argon mixture of 30.0 - 27.0 volume percent concentration at temperature of 1300 °C; 5 - 15 % of coating is deposited by pyrolysis of propylene and argon mixture of 5.0 - 10.0 volume percent concentration doped with 0.5 - 1. 5 volume percent of methyl trichlorosilane. Third layer of silicon carbide is deposited by pyrolysis of methyl trichlorosilane and argon mixture of 2.5 - 3.0 volume percent concentration in hydrogen-argon mixture at temperature of 1500 °C. Upon deposition this layer is treated with hydrogen at temperature of 1750 -1800 °C for 20 - 30 minutes. 90 - 95 % of fourth layer is deposited by pyrolysis of acetylene and argon mixture of 40.0 - 43.0 volume percent concentration and of argon and propylene mixture of 30.0 - 27.0 volume percent concentration at temperature of 1300 °C. Upon deposition of 90 - 95 % of fourth-layer pyrocarbon coating thickness 5 - 10 % of coating is deposited by pyrolysis of propylene and hydrogen mixture of 3.0 - 5.0 volume percent concentration.
EFFECT: enhanced service life of fuel microelements due to reduced damage probability during their manufacture and in service.
1 cl, 6 dwg, 1 tbl
FIELD: nuclear engineering, in particular, engineering of micro heat-exhausting elements for nuclear reactors.
SUBSTANCE: first layer of micro heat-exhausting element with four-layer protective cover is made of SiC-PyC composition with content of 1,0-10,0 % of mass of silicon carbide with thickness of layer equal to 0,02-0,2 of diameter of fuel micro-sphere, second layer is made of SiC-PyC composition with content of 20,0-45,0 % of mass of silicon carbide with thickness of layer equal to 0,03-0,40 diameter of fuel micro-sphere, third layer is made of silicon carbide, while fourth layer is made of titanium nitride with thickness equal to 0,01-0,08 of diameter of fuel micro-sphere.
EFFECT: increased exploitation resource of nuclear reactor due to increased corrosion resistance and radiation stability.
3 dwg, 1 tbl
FIELD: nuclear power engineering; manufacture of fuel elements and their claddings.
SUBSTANCE: each weld of cladding and its plug are tested in facility equipped with units for clamping and revolving the claddings, scanning with carriage using weld inspection piezoelectric transducer and piezoelectric transducer for measuring wall thickness in measurement region, immersion bath, ultrasonic pulse generator, ultrasonic pulse receiver, microprocessor, analog-to-digital converter switch, and random-access memory.
EFFECT: enhanced quality of fuel elements and their operating reliability in reactor core.
1 cl, 1 dwg
FIELD: nuclear power engineering; fuel rods for water-moderated water-cooled reactors.
SUBSTANCE: proposed fuel rod designed for use in water-cooled water-moderated power reactors such as type VVER-1000 reactor has fuel core disposed in cylindrical can. Outer diameter of fuel rod is chosen between 7.00 . 10-3 and 8.79 . 10-3m and fuel core diameter is between 5.82 . 10-3 and 7.32 . 10-3m and mass, between 0.93 and 1.52 kg, fuel core to fuel rod length ratio being between 0.9145 and 0.9483.
EFFECT: reduced linear heat loads and fuel rod depressurization probability, enlarged variation range of reactor power, optimal fuel utilization.
7 cl, 3 dwg
FIELD: process engineering.
SUBSTANCE: invention relates to high-temperature fuel cells. Invention discloses fabrication of said fuel cell incorporating tubular electrolyte with application of at least one internal electrode and at least one external electrode that consists in the steps that follow: moulding core is made whereon applied is at least one material that makes an interconnection and internal electrode and placed in the mould for injection moulding of electrolyte to remove moulding core in the matter of moulding of one-shot moulding with moulding core.
EFFECT: simplified application of interconnection ply.
12 cl, 6 dwg