Automated assembly line fuel elements for nuclear power reactors of the type bn
(57) Abstract:Usage: in nuclear engineering, at the Assembly of fuel rods. Entity: line put: machine washing and drying of the ends of the casing pipe and the inner surface, which eliminates acidic or alkaline treatment, solved the problem of disposal, the 4-way machine that allows you to set the fuel column of tablets with various degrees of enrichment at the same time in the 4th shell pipe, thereby providing the specified performance, the machine control the tightness, allowing you to control the weld bead along the edges of the shell. Together with other newly introduced machines ensure a better quality of Assembly of the fuel rods. 9 Il. The invention relates to the field of nuclear engineering, and specifically, to an Assembly of fuel elements used in nuclear reactors on fast neutrons type B. N.Known automatic installation for assembling and welding end caps onto the ends of the membranes of the fuel elements and control of welded joints (1) containing the welding station with mechanical feed stub, a manipulator for removing one cap feeding mechanism and installed in the open end of the shell is gluske 1 and II, control station for examination, the reading station and a control station connected to the computer, which processes the data control, by matching each weld joint specifications and generates a signal of acceptance or rejection by binding signal to the corresponding serial number of the stub signals. Signals from the computer are transferred to the sorting station, located at the output end of the conveyor to move the tubular membranes and guide each shell in accordance with the signal of computers in the party good or defective products.The disadvantage of this setup it solves the problem of automated Assembly only partially, namely, welding the caps to the pipe shell.A device for filling fuel tablets shells TVEL (2).The device has a fuel tablets on the comb in several rows, of a certain length, by using located at the rear ends of the rows of the pusher inserts tablets rows in a tubular sheath, arranged in series in the direction of the front ends of the series of tablets.The device is characterized in that the pusher drive containing the roller, movable source section is. icag connected with having two vertical emphasis by the pusher through disposable alternately supports and stops using passing through them through the rolling axis.Between the supports and the supports on the axis of the set spring. On the rear end of the fixed axle sensor overload that comes into contact with the stop moving backwards with overcoming the force of the spring pusher, defining it presses the force and in the event of an overload submits to the drive source, a stopping signal, causing him to stop.The drawback is that the design does not allow reaching the fuel pillars tablets in a given rhythm.A known machine for loading tablets (3) containing tray with pills that are installed on the table, fixture, guide pills with tray in a tubular shell, grille to remove fragments of tablets, which is located between the tray set on the table, and a device; a mechanism for pushing the pellets out through the bars of the shell, and a controller having a system of sensors, force push tablets mechanism. The controller compares the measured maximum amount of force required for loading into the shell of the required number of tablets with the signal from A design is the complexity of the embedding machine in the proposed automated line.Closest to the technical essence, the number of process and control operations, and achieved technical result is "a System for the Assembly of nuclear fuel elements used in the Assembly of the fuel rod using a mixed fuel (4) and (5).System for assembling a fuel rod includes:
installation of equipment containing apparatus for the introduction of fuel pellets in the open ends of the shells TVEL;
installation insert the terminal fittings (plugs) containing end components for installation, and welding device for welding end fittings to the sheath of the fuel element for sealing fuel pellets and forming thus TVEL;
the sealing device connected with Assembly facilities;
transport devices for lateral transfer TVEL from installation to installation in the form of a conveyor mechanism that has a holder for fastening of the fuel cladding during transport, as well as an exciting mechanism for the hard grip shells during the Assembly process and moving forward, adjusting the length of the shell within the specified Assembly workplace.In the known installation is key end pieces to the shell, and the device for equipment not allows you to simultaneously send a few shells fuel tablets with different enrichment and cannot provide the rhythm of the line, i.e., the specified performance.The present invention solves the problem of creating an automated Assembly line for the fuel elements of type bn with a high degree of automation.The problem is solved in that in the automated Assembly line for the fuel rod containing the downstream drive, machine transport, automatic trimming the ends of the shell, automatic calibration-tarnovci, machine poklevki, automatic pressing of the tip, marking, welding of the 1st seam, machine spacer, automatic fixing of the fuel column, automatic dedusting machine pressurization with helium and the input terminal parts, machine welding of the second seam, machine robot transport, installation of I / o products, the installation of pollution control, packaging, interconnected shop transport and management system in the form of several stations with group management, automated line is supplied with the installation of the washing and drying of membranes installed between the machine calibration-tarnovci and machine p is excavated shells, and installed on the guides with the possibility of reciprocating movement relative to the axis of the shell and provided with a pipe for supplying water under pressure and drying by hot air, between the machine spacers and automatic fixing of the fuel column is selected by the 4-way machine horizontal gear casings fuel tablets with varying degrees of enrichment, containing 4 feeder, each of which is provided with a bevel drive with, weighing and equipment, transport between robotic systems and installing I / o products posted by machine washing of fuel rods containing a bath with hot distilled water, installed it magnetostrictive transducer and pulling mechanism and machine control pollution device for welding the spacer wire containing the clamping frame and underneath the plate fixed on the support device and the guide sleeve with a groove, to pass through it, the spacer wire, the ends of which the applied force, for example, cargo.Comparative analysis of the prototype showed that the claimed Avtomat control the tightness, machine equipment, machine wash products, a device for welding the spacer wire on the outer surface of the product, which meets the criterion of "novelty."The comparison of the proposed solutions with other analogues showed that the introduction of machine washing and drying shells products helped to ensure the continuity of the process and Assembly at a given rhythm and to simplify the technology of washing with the simultaneous processing of up to 8 pieces, solved the problem of disposal of this operation.The introduction of the 4-way machine equipment made it possible to collect the fuel column with varying degrees of enrichment in the 4th shell and to provide the rhythm of the lines.The introduction of machine control tightness in separate hot cells in an amount up to 10 pieces simplifies control technology and provides the rhythm of the line and the required performance.Device for welding the spacer wire installed at the finish of the process, simplified the majority of process and control operations.The technical result in the creation of an automated line, miragedrive, employed on the line 30 to 7 people;
stabilization of production technology by improving the quality of products and the anticipated reduction in the number of marriage from 12% to 0,2 0,3%
reduction of production space 1.5 times.Thus, the invention meets the criterion of "inventive step".In Fig. 1, 2, 3, 4 shows a plan of the entire line of Fig. 5 plan of machine washing and drying of the membranes; Fig. 6 section a And Fig. 7 type B host pipe clamping shell when washing and drying; Fig. 8 a plan of the machine equipment of the casing pipe fuel tablets; Fig. 9 schematically shows the installation of air-tightness control products 1 weld.Automated line contains the machines and devices of varying complexity, performing all process and control operations from supply of raw materials and components to packaging of the finished fuel element.Pipe coating is transferred via a rack and pinion stepper conveyor in the form of a simple and reliable model of the elements of the modules.The modular principle of the line much easier to process and control equipment. Transitional elements between modules, in addition to the basic functions swail 1 in the form of inclined rails, to accommodate the pipe wrapper;
motor machine 2, consisting of fixed and moving rails with the actuator installed on a shared basis with the ability to capture membranes and in subsequent articles, and step motion to conduct process and control operations;
machine for trimming the ends of the tube-shell 3 at a given size, consisting of a frame with the attached rotating spindle with the cutting head and the collet actuator for fixing it pipes;
machine calibration-tarnovci 4, consisting of a clamp actuator, caliber collet with the mandrel for tarnovci the inner diameter of the pipe coating to a predetermined value;
machine for degreasing and drying of the membranes 5, consisting of wash chambers with drives that are installed on the ends of the casing pipe with the possibility of axial counter-move camera on the pipe ends.The washing chamber is provided with nozzles for the supply of hot distilled water and air. To prevent displacement of the pipe when washing and drying has a clamping mechanism with the drive.machine for poklevki pipes 6, including a focus for trumpet-shell, sliding glass, interacting with the punch and drive;
but-translational axial movement and clamping of the shell;
machine marks 8, consisting of a drummer with a digital stamp and prism for positioning the handpiece;
machine welding of the 1st seam 9, consisting of a sealed chamber and placed in her electrode for welding tip, grandpaboy welding;
machine to control the tightness 10 of the first seam, consisting of measuring the hot cell into which fits the end of the pipe stub.The camera is connected to a helium leak detector;
machine to enter the spacers 11, which includes a clamp for pipe coating, rod driven for reciprocating motion;
machine horizontal gear 12, consisting of a box with 4 feeder with download sites and feeding tablets and equipment of their shells;
automatic fixing of the fuel column 13, consisting of a clamping shell with blank, tablets, rod actuator and latch;
machine for removing dust shells 14, consisting of a vacuum receivers with filter and valve.The shell is filled with tablets, is installed in the receivers, and is sealed by a seal;
machine for crimping helium and the input end of the part 15 has a body shop, within which ramadanramadan supply of helium and vacuum;
machine for welding the second seam 16, consisting of a manipulator for installation of a fuel rod in a vertical position with the subsequent welding of stubs to the shell in the welding head arc controlled by a magnetic field in an argon atmosphere;
machine to control the tightness of the second seam 17, similar to the machine 10, but has no feeder helium;
transport robotic complex 18 in the form of a pivotally mounted lever for fence products with road machine, followed by a rotation by 90oand transfer to a machine for washing;
machine for cleaning rods 19, consisting of feeders and feed drive, bath with compartments filled with hot water and set it by the ultrasonic transducer.Bath is equipped with nozzles for the supply of hot air, water and ventilation;
setting for output and input products 20 consisting of the feed and draw mechanisms and designed for change and the direction of movement of articles on the horizontal axis transverse movement;
installation for welding the spacer wire 21, consisting of a base, with established therein rotating centers with the drive mechanism d is znanosti rods 22, consisting of a motor module, on which the housing is installed detectors alpha radiation, determining the level of contamination of the products;
the machine is to control the appearance and packaging 23, consisting of a well-lit table, a motor module and a transport conveyor;
machine washing and drying the membranes 5 Fig. 5, 6, 7 contains two wash chamber 24, between which the pipe coating 25;
each chamber 24 is equipped with a pneumatic actuator 26 with the possibility of axial movement relative to the shell.The camera 24 includes a housing 27 within which is placed the actuator 28 that interacts with the lever 29 through the sleeve 30 and then acting on the sealing element 31. For fixing the casing pipe 25 is installed, the device 32 with the actuator 23 and movable jaws 34;
machine horizontal equipment Fig. 12, Fig. 8 consists of a sealed glove box 35, within which is placed the 4th of vibrating feeder 36 with a feed tube 37. Each feeder is equipped with independent drive (Fig. not shown). Extreme vibrating feeders are designed for a set of fuel post their tablets low enrichment, average - above the Sheath 25 can move in the axial direction to the lodgement 39 feeder 36 roller mechanism 40;
machine control the tightness 10 Fig. 2, figs. 9 contains hot chamber 41 with the helix 42, is placed inside the chamber, the shell 25 is welded to the bracket 43, and the open end of the shell 25 in a sealed chamber 44 in which is helium.Hot chamber is connected to the helium leak detector 45.Assembly of fuel elements on this line is as follows
Design of a fuel rod allows you to organize its Assembly in the horizontal plane, by the ends of the casing pipe process and control equipment.Pipe coating 25 serves to drive 1, where they go on road machine 2, the movable rail piece which carries the casing pipe for conducting process and control operations.1 the operation of the trimming of the ends of the tube-shell size is automatically trim the ends 3, further jacket pipe is fed to the machine calibration-tarnovci 4, where the sludge pipe ends, then motor machine 2 carries them to machine washing and drying 5. On command from sensors products pipe coating 25 are held by pnevmatikatos 32. With the help of a pneumatic cylinder 33 and the movable jaws 34, further to the ends of the positive element 31.Pump is switched on and supplies water from the tank (to hell. not shown). In the tank is maintained level and temperature automatically. After washing for 2.5 min, the water is drained, then the blowdown pipe hot air for 15 sec. Then washed membranes are dried for 2.5 min with hot air.Simultaneously processed 8 tubes: 4 wash, then 4 dried.After washing pipe coating 25 is received on the machine poklevki pipe 6, where in a given section are applied deepening-poklevki used to hold the fuel column.The next operation pressing the tip into the casing pipe 25 on the machine pressing 7 by axial movement of the movable quill installed in it by the tip 44.The next operation the marking is done on the machine marks 8 shock by digital stamp and application of the relevant index on the tip on the prism.The operation of the first seam welding is carried out on the welding machine 9 during the rotation of the pipe, in an atmosphere of argon-arc welding.Control the tightness of the first weld is carried out on the machine, leakage testing 10 through helium Technika is here pipes helium under pressure.Control are simultaneously 10 pipes with welded tip.Enter into the open end of the shell supporting details spacers, which supports the fuel column is the machine to enter the spacers 11, through axial movement of the rod with spacer until it stops in the form of puklavec on the inner surface of the pipe coating. Because the spacer is a cylindrical part with a frame, and the orientation of its very simple.Jacket pipe with welded tip motor machine is transferred to the machine horizontal gear 12, is placed in a sealed box 35, and then pulling mechanism 40 is moved in the axial direction against the tray 39 feeder 36. Before equipment automatic weights determined by the weight of the empty tube-shell 25.The present sensor products includes vibrating feeder 36 and the portion of the fuel column reduced enrichment, typed at the feeder, is fed into the internal cavity of the 1st trumpet-shell, then the latter is weighed and transferred transversely to 1 medium feeder 36, which likewise saddled fuel column, but with an increased obogashenii enrichment set the fuel column, automatically weighed and transferred to the last feeder enrichment of the fuel column as in the first extreme, the vibratory feeder.If full fuel pole mass does not match the set tolerance, it is automatically removed from the process stream for marriage.Thus, the 4-way machine equipment allows to increase the productivity in 4 times and due to the simultaneity of the set of parts of the fuel newels in the 4th shell, which gives the opportunity to meet normalized performance 1 TVEL per minute. The operation of the equipment is harmful to health, dusty, therefore, all manipulations with tablets produced inside an airtight box 35.Next motor machine 2 carries curb the casing pipe with a cap on the machine fixing of the fuel column 13, where the shell of the piston rod of the actuator is inserted cylindrical spring retainer to lock in the fuel column, after which the catch here rasklinivanie, ensuring the stability of the position of the tablets inside the shell.The operation of removing dust from the open end of the casing is provided in the machine, dedusting 14, where the vacuum receivers of sabien the tailoring machine 2 transfers the filled shell on the machine 15 pressurization with helium and the input terminal parts with an open hand.The atmosphere inside the shell (Fe) must contain at least 95% helium, therefore, pressurization of helium is carried out in a sealed chamber, where the cavity of a fuel rod at the beginning vacuumized, then served helium gas under pressure and the piston rod in the axial direction shall be expedited plug into the open cavity of the shell and tightness closes it.Further operation of the second welding seam is carried out on a robotic complex 16, which takes the product from the machine crimp 15 arm and moves it from horizontal to vertical, introduces the welding head, the welding of the 2nd weld arc controlled by a magnetic field in an argon atmosphere.The same manipulator returns the product in a horizontal position and delivers a ready-made fuel rod to control the tightness of the second seam on machine 17, which is similar to the machine control tightness 10 1 weld, but has no feeder helium. He also decationizing.After the transport machine 2 carries TVEL on robotic transport sector 18, and the latter is made in the form of rotating around its axis of lever-lodgement translates the transportation of a fuel rod from transverse to p is C tight holes performed at the inlet and the outlet of the chamber, which is divided by partitions into several compartments. Rinsing is carried out in hot distilled water in an ultrasonic field generated tubular magnetostrictive transducer, followed by drying with hot air.Next, the installation 20 with the feed and transport rollers, translates the transportation of a fuel rod from longitudinal movement in the transverse and submits it to the setting winding the spacer wire 21. TVEL is mounted on the plate attached to the caliper installation.The spacer wire is passed through the sleeve of the device and secured to the load, providing a tension in the winding, which is carried out while rotating the fuel rod. At the end of the winding wire is attached to the fuel rod from the upper tip of the device.Then the ends of the wire are cut and produced by argon-arc welding of the ends of the spacer wire.Then the finished fuel transport machine 2 are transferred to the machine control alpha contamination 22, pass under a system of detectors, where compliance is determined by the level of contamination of hard mezhdunarodnoi, inspected by the controller, and then the groups are placed in a special transport container 23 are closed sealed cover and sent to the Assembly.The proposed line has been tested, tested, testing of all components and assemblies, control systems, launched in pilot operation, and it made the party goods held reactor testing at nuclear power plants.In the second half of 1994 automated line should reach the planned performance and to ensure 100% performance targets for the production of these products. Automated Assembly line fuel elements for nuclear power reactors of the type bn, containing the downstream drive, automatic cutting sheath, automatic calibration-tarnovci, machine poklevki, automatic pressing of the tip, marking machine, automatic welding, first weld, machine input spacers, automatic fixing of the fuel column, automatic dedusting machine pressurization with helium and the input terminal parts, machine welding of the second seam, the machine-robot transportation, installation of I / o products, the installation of pollution control, installation package, linked malper who eat it is fitted with installing the washing and drying of membranes installed between the machine calibration-tarnovci and automatic poklevki pipes and made in the form of hot cells containing nodes sealing by the number of simultaneously processed shells and installed on the guides with the possibility of reciprocating movement relative to the axis of the shell and provided with a pipe for supplying hot water under pressure and drying by hot air, between the machine spacers and automatic fixing of the fuel column has four machine horizontal gear casings fuel tablets with varying degrees of enrichment, containing four feeder, each of which is equipped with a self-driven with ability to set weighing and equipment, transport between robototehnicheskih complex and installing I / o products posted by machine washing of fuel rods containing a bath with hot distilled water and placed in it a magnetostrictive transducer and pulling mechanism and machine control pollution device for welding the spacer wire containing the clamping rallies her the spacer wire, to the ends of which applied force, such as cargo.
FIELD: atomic power engineering.
SUBSTANCE: device has welding chambers having apertures for inputting covers for pressurization, which concurrently are output apertures of heat-conductive elements, welding chambers electrodes, power source, transporting module for transverse product feed, common control system with blocks for parallel and serial connection, device for forming a break in secondary contour. Welding chambers are placed in parallel to each other at distance from each other, determined from formula S=t(m k+1), where S - distance between chambers axes, t - step of transport module, k - number of chambers in device equal to number of steps of transporting module in each singular step thereof, m - any integer starting from one, and control systems connected through parallel connection block to working tools of device of same names, and through block for serial connection to welding force drive and to device for forming break in secondary contour of power source, as well as to power source connected in parallel to welding chambers electrodes.
EFFECT: higher efficiency.
4 cl, 1 dwg
FIELD: nuclear power engineering.
SUBSTANCE: proposed method is used for manufacturing fuel assemblies for type VVER-1000 and VVER-440 reactors. In order to check spacer grid for passability it is placed in machine between two covers with depressions that follow grid outline and blind holes coaxial to each subchannel of grid accommodating calibrated balls, then it is tuned together with covers through 180 deg., subchannels of inadequate caliber are detected and burnished by means of drift. For checking diameter of circumference inscribed in subchannel the grid is placed in machine equipped with large-diameter calibrating balls, subchannels through which these balls have passed are detected and squeezed by means of clamping tool with jaws disposed in holes between subchannels. Decision on quality of spacer grid subchannels is taken by sticking of balls in them as spacer grid is turned in machine through 180 deg. Balls of different diameters are differently colored.
EFFECT: enhanced quality and yield of spacer grids.
2 cl, 4 dwg
FIELD: machine-assembly equipment for producing nuclear reactor fuel assemblies.
SUBSTANCE: proposed machine has pneumatic cylinder rod provided with its motion limiter and contactless sensor at drifting mechanism on through slit of bottom end part of fuel element; cone angle of drift-rod is 30 deg. and annular drilling diameter in each hole of auxiliary spacer grid equals nominal flare of fuel element end part sections internally drifted inside each annular drilling within upper nominal-size tolerance D = Hk, where D is annular drilling diameter; H is nominal flare; k is upper nominal-size tolerance.
EFFECT: enhanced quality of fuel assembly.
1 cl, 5 dwg
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: power engineering, namely nuclear power reactors, particularly sealing of fuel elements by means of contact butt welding with use of plugs.
SUBSTANCE: apparatus includes sealed welding chamber with housing non-detachable at operation and having through duct for feeding parts to welding zone; mechanisms for sealing welding chamber; device for feeding parts to welding zone; additional clamp of tube; mechanisms for gripping and fixing welded parts; drive device for supplying welding pressure; autonomous drive units. Mechanisms for gripping and fixing welded parts are in the form of collet chucks with respective drives. Welding pressure supply drive device is connected with electrode holder of plug. Welding chamber is restricted by non-detachable housing and flange-current supply lead that is fluid -tightly connected with housing and fixed relative to housing at operation. One collet chuck has annular detachable current supply lead in the form of sectors and it rests by its end at side of large base of petal cone upon said flange-current supply lead. Collet chuck of tube grip and electrode-holder of plug have coaxial electrically insulated one relative to other tie rods arranged in through duct of chamber and joined with autonomous drive units.
EFFECT: enhanced stability of process, improved quality of welded joint due to lowered misalignment of tube and plug.
FIELD: nuclear engineering.
SUBSTANCE: proposed method primarily used for manufacturing spacer grids of VVER reactor fuel assemblies involves pre-compression of dynamometric clamp by welding gun electrodes prior to spot welding of shaped subchannels beyond subchannel field, evaluation of compression of welding gun electrodes by displacement distance of clamp jaws and force indicator readings, whereupon information about this compression force is processed in computer and passed to spatial displacement actuating mechanism of welding gun for conducting spot welding of shaped subchannels in assembled field when compression forces of electrodes comply with desired values or for ceasing spot welding when compression forces do not comply with desired values, this information being displayed on computer monitor.
EFFECT: enhanced quality of spacer grid manufactured by this method.
1 cl, 3 dwg
FIELD: nuclear power engineering; spacing apart fuel elements in reactor fuel assemblies.
SUBSTANCE: proposed method includes insertion of auxiliary inserts in assembly field holes designed for guide channels and central tube with desired inscribed circumference in each hole prior to spot welding of subchannels to join them together in assembled field; these auxiliary inserts have same diameter as guide channel and central tube and their temperature coefficient of linear expansion equals that of subchannel material; spot welding of subchannels to each other and to rim is effected while inserts are installed and upon heat treatment these inserts are removed.
EFFECT: enhanced quality and yield of spacer grids.
1 cl, 1 dwg
FIELD: nuclear power engineering; manufacture of fuel elements for fuel assemblies of nuclear power reactors.
SUBSTANCE: proposed process line has mechanism for press-fitting bottom plug in calibrated end of can provided with cutoff gear for piece-by-piece feeding of bottom plugs of different types that incorporates bottom plug passage duct accommodating C-shaped member with reciprocating horizontal-motion actuator whose top flap has slot engageable with upper cylindrical part of bottom plug; bottom flap is longer than top one and is provided with bottom plug passage hole shifted toward edge of bottom flap; flaps are spaced apart through distance slightly longer than maximal length of thick end of bottom plug; rod designed for press-fitting bottom plug in calibrated end of can has bed with seat to receive bottom plug, maximal-size portion of seat following shape of bottom plug.
EFFECT: enlarged functional capabilities of process line for manufacturing fuel-element cans of different sizes.
1 cl 7 dwg
FIELD: mechanical engineering.
SUBSTANCE: proposed method is intended for manufacturing fuel elements using resistance-butt welding primarily for their joining to zirconium alloy cans. Welding is effected at equipment electrical resistance not over 30-fold resistance of can section forming welded joint having or not point discontinuities in the form of separate spots or chain of such spots forming no continuous line and measuring maximum ten thicknesses of weld in cross-sectional area of welded joint under check disposed at distance equal to two or three thicknesses of can wall from butt-end of plug located inside fuel element, welded joint being checked by uniformity of external fin. Length of poor fin formation section does not exceed 10% of joint perimeter.
EFFECT: enhanced quality of welds and reliability of fuel element sealing.
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