Tvel for integral fuel cartridge nuclear reactor (rbmk)
The invention relates to nuclear energy, in particular for fuel Rods for the fuel cartridges of nuclear RBMK-type reactor consisting of two fuel assemblies (FA), and can be used in Fuel elements and other assemblies, in which it is necessary to reduce a local burst of neutrons, causing increased energy. The technical result - the reduction of energy release at the ends of the fuel Rods in the center of the active zone, which will provide a more uniform deep the burn-in length and, consequently, improve the safety of a nuclear reactor. In a fuel rod for a composite fuel cartridges of nuclear RBMK-type reactor consisting of a cylindrical zirconium shell, sealed at one end by a plug, and the other with the tip inside the fuel pellet of uranium dioxide and the spring retainer of the fuel column, between the end plugs and the adjacent fuel pellets placed absorber of excess neutrons, which is a washer made of a material containing hafnium. 2 C.p. f-crystals, 2 ill., 1 PL.The invention relates to nuclear energy, in particular for fuel Rods for the fuel cartridges of nuclear RES, in which it is necessary to reduce a local burst of neutrons, causing increased energy.A known design of a fuel rod , consisting of filled fuel tablets sealed shell, which is used in the fuel cartridge, consisting of a single fuel Assembly. The power control in such FA spend the vertical movement of the absorbing rods in the guide channels. In Fuel elements such TVs release height is nearly constant except for the ends where it is lowered. This energy deposition in the fuel Rods is characteristic only for fuel cartridges, consisting of a single fuel Assembly and enables the adjustment of the power absorbing rods.In the fuel Rods of such cassettes fuel burn is almost uniform in height, and their efficiency is high. However, the use of such fuel cassettes, consisting of a single fuel Assembly, is limited by the height of the active zone of the nuclear reactor.Known TVEL taken by the authors for the prototype , consisting of a cylindrical zirconium shell, sealed at one end by a plug, and the other tip, inside which are preloaded spring retainer fuel pellets of enriched uranium dioxide. This is The Central pipe. Structurally, the cartridge is made so that the area of intersection of two fuel assemblies in the center of the active zone is the gap on the fuel pole due to the presence of a water gap height of 30 mm between the ends of the fuel Rods and two plugs 9.5mm height of zirconium alloy with cross-capture of thermal neutrons is not more than 0.2 barn.The disadvantage of the prototype is the increased energy at the ends of the fuel Rods in the center of the active zone of the nuclear reactor caused a local outbreak of the neutron field due to a rupture in the fuel height fuel cartridge. When in the fuel Rods of the fuel with an enrichment of 2.6% uranium-235, the amount of non-uniformity of energy deposition at the ends of the fuel Rods can reach up to 1.34. The main change of the energy release occurs at a distance of 20-30 mm from the extreme ends of tablets. The result is a substantial increase in the power density at the ends of the fuel Rods decreases their health (depressurization of the fuel Rods occurs mainly in the center of the active zone, until the separation of the plugs, safety in emergency situations and the deterioration of the economic performance of nuclear power plants, including due to the inability of the operation of the fuel Rods with a 100% power for the entire length (there is a limitation of the proposed invention, is to reduce the power density at the ends of the fuel Rods in the center of the active zone, which will provide a more uniform deep the burn-in length, increase efficiency of FA and security of a nuclear reactor, including in emergency situations.The solution of the technical problem is achieved by the fact that a fuel rod for a composite fuel cartridges of nuclear RBMK-type reactor consisting of a cylindrical zirconium shell, sealed at one end by a plug, and the other tip is inside the fuel pellet of uranium dioxide and the spring retainer of the fuel column, between the end plugs and the adjacent fuel tablet placed absorber of excess neutrons, which is a washer made of a material containing hafnium.In the private embodiment, the washer is made from an alloy of hafnium to zirconium in the zirconium content of 0.1 to 50 wt.%.In another private embodiment, the washer is made from an alloy of hafnium and titanium in the titanium content is from 0.1 to 50 wt.%.In another private version in the cylindrical shell are fuel pellets of uranium dioxide only staff enrichment.Hafnium is compatible with the materials of the shell, end caps and teachinig conditions above, than that of zirconium alloys. The cross-section capture the hafnium 105 barn, during operation ability hafnium changes slightly.The influence of the thickness of the washer to reduce the power density in the center of the active zone at the ends of the fuel Rods in the outer row of cassettes RBMK-1000 fuel enrichment 2.8% and the content of erbium 0.6% in the area of juncture of the two beams in the center of the active zone are shown in table 1.From the presented results it follows that in the fuel Rods of the RBMK-1000 without washer-scavenger of excess neutrons at the ends in the center of the active area is increased power density to a value of 1.34. Washer thickness of 0.6 mm reduces the initial burst to 1.11, and washer thickness 1,0 mm eliminates surge energy almost completely.The invention is illustrated by drawings.In Fig.1 shows a longitudinal section of a fuel rod, comprising a shell 1, the stub 2, tip 3, the fuel pellets 4, the spring retainer 5. Additional absorber of excess neutrons 6 in the form of a washer made of hafnium or an alloy of hafnium to zirconium is located inside the fuel rod between the inner end of the stub and the adjacent tablet of uranium dioxide.In Fig.2 shows the plug 2 washer 6.TV is moderator and coolant distilled water is used, and as a nuclear fuel is enriched uranium dioxide. During operation of a nuclear reactor in the center of the active area of the junction of the two bundles of fuel Rods due to the presence in this area of water gap height of 30 mm and two zirconium plugs (G,5 mm) with a cross-section of capture of thermal neutrons is not more than 0.2 barn, formed a local burst of energy neutron field, which causes increased up to the value of 1.34 was initiated at the ends of the fuel Rods. Placed between the inner end of the stub and the adjacent fuel tablet washer, made of hafnium or an alloy of hafnium from zirconium, with a cross-section of the grip 105 barn absorbs some of the neutrons and thereby aligns the energy deposition along the length of a fuel rod. In addition, the replacement of two on-screen tablets from depleted uranium washer from hafnium allows to increase the load of the fuel in the fuel rod, which will give an opportunity to improve the economic performance of nuclear power plants.The larger the mass of hafnium in the fuel rod, the larger value decreases the energy deposition at the end of the fuel element.More energonaprjazhenie fuel cartridges of nuclear reactor RBMK-1500 (similar in design RBMK-1000), in which high local energy deposition in the Oia at the ends of the fuel Rods in the center of the active zone in the fuel pole plugs put two screen tablet height 30 mm dioxide uranium of low enrichment , in the result, the amount of non-uniformity of energy deposition along the length of the fuel rod is reduced to 1.25 to 1.34. Hafnium more efficient and to a lesser extent, in comparison with depleted uranium dioxide, levels of energy along the length of a fuel rod. So, two screen tablet with a total height of 30 mm from the uranium dioxide enrichment 0.7% uranium-235 in the fuel Rods of the RBMK-1500 reduce the surge of energy at the ends of the fuel Rods in the center of the active zone of 1.34 to 1.25, while for obtaining the similar effect of reducing the energy deposited in the fuel Rods at the ends enough washers from hafnium thickness of only 0.2 mmThis loss in fuel burnup using the two screen tablets from depleted uranium dioxide is 1.8%, and the use of washers of hafnium thickness of only 0.2 mm 0,42%. In the present invention are fuel pellets only staff enrichment.A new technical result of the invention is that when used in a fuel cartridge of the fuel Rods washers from hafnium or an alloy of hafnium from zirconium, or hafnium alloy with titanium, which is located between the inner end of zirconium plugs and fuel tablet, provides high performance TVs, reduces the number of permeti cost of generated electricity. Use in RBMK-1500 tablets regular enrichment will increase the energy deposition along the entire length of a fuel rod, which will enhance the economic performance of nuclear power plants.Sources of information1. Emelianov, I. E. nuclear Power reactors. - M.: Energoatomizdat, 1984, S. 18-30.2. Dollezhal N. A. Channel nuclear power reactor. - M.: Atomizdat, 1980, S. 54-55, 95-97.3. K. Almenas, A. Kaliatka, E. Uepuras. Ignalina RBMK-1500. A Sourse Book. - Lithuanian Energy Institute, 1998, p. 62-64.
Claims1. TVEL for the composite fuel cartridges of nuclear RBMK-type reactor consisting of a cylindrical shell, sealed at one end by a plug and the other end in which is located the fuel pellet of uranium dioxide and the spring retainer of the fuel column, characterized in that between the end plugs and the adjacent fuel tablet placed absorber of excess neutrons, which is a washer made of a material containing hafnium.2. TVEL under item 1, wherein the washer is made of an alloy of hafnium to zirconium in the zirconium content of 0.1 to 50 wt.%.3. TVEL under item 1, wherein the washer is made of an alloy of hafnium and titanium in the titanium content is from 0.1 to
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: nuclear power engineering; tubular dispersed-core three-layer fuel elements.
SUBSTANCE: proposed method includes production of powder mixture, powder mixing in plasticizer environment, cold molding in core billet with plasticizer, thermal sintering, hot molding-calibration of fuel core, core placing in can made in the form of sleeve with annular slot, calibration, hot molding through die, and drawing; inner surface of external can of sleeve is provided with longitudinal bulges and outer surface bears bulge location marks; fuel core is provided with longitudinal flats and placed in sleeve taking care to align bulges of the latter with core flats; in the course of drawing marks are aligned on arbor ribs.
EFFECT: enhanced stability of active layer and can thickness in shaping polyhedral fuel elements.
1 cl, 4 dwg
FIELD: nuclear power engineering; manufacture of fuel elements for nuclear reactors.
SUBSTANCE: process line primarily used for manufacturing fuel elements for VVER-1000 and VVER-440 reactors has charged can weighing device built integral with can-and-plug assembly weighing device that determines net weight of charged can by internal components, box holding devices for discharging fuel pellets from rejected fuel element, destructive testing of helium pressure within can, and preparing specimens for metallographic inspection.
EFFECT: enlarged functional capabilities of line, improved quality of fuel elements, enhanced yield.
1 cl, 9 dwg
FIELD: nuclear engineering; manufacture of plate-type fuel elements.
SUBSTANCE: core for three-layer assembly that has sleeve, circular core, and plugs is provided with longitudinal bonds made of sleeve material and three-layer tube obtained upon joint hot extrusion and drawing is cut along bonds; segments obtained in the process are drawn through slit die.
EFFECT: reduced labor consumption due to reduced number of pre-heat rolling operations.
1 cl, 5 dwg
FIELD: fuel cells designed for use in gas-cooled nuclear reactor core.
SUBSTANCE: fuel cell 10 designed for use in gas-cooled nuclear reactor has assembly of two adjacent fuel plates 12a, 12b disposed relative to one another and shaped so that they form channels 14 for gaseous coolant flow. Fuel plates 12a, 12b incorporate elementary fissionable particles, better non-coated ones, implanted in metal matrix. Metal coating may be deposited on both ends of each plate 12a and 12b.
EFFECT: enlarged heat-transfer surface, enhanced power density per volume unit.
13 cl, 5 dwg, 1 tbl
FIELD: nuclear power engineering; production of heat-generating elements and heat-generating assemblies for research reactors.
SUBSTANCE: the invention is pertaining to the field of nuclear power engineering, in particular, to production of heat-generating elements (further - fuel elements) and the heat-generating assemblies (further - fuel elements assemblies) for research reactors using a low (less than 20 %) enriched nuclear material. The technical result of the invention is enhancement of production capabilities for upgrading the existing research reactors, the fissile regions of which differ in dimensions and forms, using the universal rod-shaped fuel element and the based on it fuel elements assembly. The fuel element is made in the form of a tubular sealed on its end faces by plugs shell made out of an aluminum alloy of 0.30 up to 0.45 mm thick with four distancing screw-type ribs on the outer surface. The diameter of a circumscribed circle of a fuel element cross section makes from 4.0 - 8.0 mm. Each rib protrudes above the shell from 0.4 up to 1,0 mm in height and is placed in the cross section plane at an angle of 90° to the neighboring rib and twisted in spiral with a step from 100 up to 400 mm, predominantly from 300 up to 340 m. Inside the shell there is a fuel core made out of a dispersive composition of uranium-containing particles and an aluminum alloy, in which a volumetric content of uranium-containing particles makes up to 45 %, the uranium-containing particles dimension makes from 63 up to 315 microns, and the shell and the core have a diffusion cohesion among themselves, formed at the fuel elements manufacture by the method of a joint extrusion through a forming array of a composite cylindrical blank consisting of the fuel element core, the plugs and the shell. On the basis of the aforesaid fuel element the versions of the heat-generating assemblies are developed for research reactors of different types with various geometrical forms of the fissile regions.
EFFECT: the invention ensures enhancement of production capabilities to upgrade the existing research reactors with different dimensions and forms of their fissile regions with the help of the universal rod-shaped fuel element and the based on it fuel elements assembly.
9 cl, 6 dwg
FIELD: nuclear power engineering; fuel compositions for nuclear-reactor fuel elements.
SUBSTANCE: can of desired size is filled with finely dispersed fuel and in addition with material forming solid matrix at temperature equal to or higher than fuel melting point. This can filled with finely dispersed fuel and material forming solid matrix is heated to temperature equal to or higher than fuel melting point is heated and cooled down.
EFFECT: enhanced fuel density and resistance to destruction at meltdown accidents.
7 cl, 2 dwg
FIELD: nuclear engineering; retrofitting subchannels of high-power uranium-graphite tank reactor cores.
SUBSTANCE: proposed method for recovering serviceability of nuclear reactor fuel assembly subchannel includes reactor shutting down, dismounting of standard floor blocks from subchannel, and removal of fuel assembly. Process channel is checked for serviceability. Channel is visually inspected within reactor for integrity and channel inner diameter profile is measured. Then process channel pre-removal operations are made. Process channel is removed from subchannel and placed in storage. Construction clearance between process channel and graphite stacking is recovered by calibrating graphite column including finishing of central bore internal diameter to desired size and expansion device segment is installed between guard plate and top graphite block. Graphite column is checked for condition by inspecting inner surface of column. Telescopic joint height and inner diameter of graphite column central bore are measured. Then process channel removed earlier and found serviceable by its check results is reinstalled in fuel assembly subchannel. After that final mounting operations are conducted including welding of process channel to adjacent structures and formation of nuclear reactor subchannel.
EFFECT: ability of evaluating process channel life, reduced dose rate on attending personnel.
1 cl, 3 dwg
FIELD: platy nuclear fuel and its manufacturing process.
SUBSTANCE: proposed nuclear fuel has regularly disposed large spherical particles of U-Mo or U-Mo-X stable gamma-phase alloy. Diameter of particles uniformly disposed in at least one additional layer on aluminum shell ranges between 300 and 700 μm. Proposed method for producing platy nuclear fuel includes production of stable gamma-phase spherical particles of alloy U-Mo or U-Mo-X, disposition of particles on aluminum shell, application of aluminum powder onto product obtained, and rolling.
EFFECT: improved ultimate working power and radiation stability at high temperature, enhanced effectiveness.
4 cl, 10 dwg
FIELD: physics, nuclear physics.
SUBSTANCE: fuel element is used in power reactors of low capacity on thermal neutrons to increase reliability and energy production. Nuclear reactor fuel element comprises shell with end plugs, core in the form of nuclear fuel particles distributed in matrix, compensator installed inside shell in the area of fuel element active part with the help of spacer component, compensator is arranged with the area of cross section in the range from 0.1 to 0.3 of fuel element cross section area, nuclear fuel particles are made in the form of granules from uranium dioxide with size from 0.2 to 1.0 mm and porosity from 3 to 6%, uranium density in core is specified from 5.5 to 6.5 g/cm3, total mass of uranium in fuel element is specified from 100 to 210 g, compensator is made from thin-walled tight gas-filled tube, compensator cross section is made in the form of cross with two axes of symmetry and rounded ribs and cavities.
EFFECT: higher reliability and increased power production.
3 cl, 2 dwg