Device for reading serial numbers of fuel assemblies
FIELD: power industry.
SUBSTANCE: device contains the first housing with through holes for passage of fuel assemblies (FA), around which illuminators are equally installed. Mirrors receiving the optical radiation reflected from fragments of side FA surface and installed with various turning angles of images provide uniform transfer of reflected mirror images to the plane of openings. The second housing with openings, which is located at some distance from the first one, is provided with radiation protection. Inside housing there arranged are video cameras consisting of video matrixes and objectives, and mirror labyrinths formed with inlet mirrors and outlet mirrors. Inlet mirrors are oriented towards outlet openings, and outlet mirrors - towards the objectives. External image control and processing unit is taken to clean room and connected to video cameras through cable communication lines. Invention is aimed at increasing radiation protection of video cameras owing to their possibility of being compactly arranged in remote housing.
EFFECT: radiation protective material and mirror labyrinths in the second housing provide additional radiation protection of video cameras.
5 cl, 4 dwg
The invention relates to the identification of fuel assemblies (FA), preferably of spent fuel assemblies (SFA), extracted from a nuclear reactor or basin storage, and intended for subsequent storage and processing.
The problem of identifying elements of nuclear power, especially SFA, recently acquired current value. As a rule, SFAS extracted from a nuclear reactor, have traces of operational impacts on the markings that make them difficult to read and identify. Herself identification marking may be an alphanumeric set of characterizing the serial number, and be done in different ways in the production process of FA. Words cause or mechanical etching, or mechanical squeezing.
Known various devices for reading such identification markings. For example, a device representing a combination of optical and ultrasonic readers that enhance the recognition accuracy of an identification code (U.S. patent No. 5.089.213, IPC G21C 017/10, 1992).
As a reader used a video camera with lights that install with providing three different angles of incidence on the reading surface.
(Nuclear Technology, Vol.72, Marc 1986, pp.321-327 or WO 9802888, IPC G21C 19/02, 17/08, 1998).
The disadvantage is that it requires precise positioning of the read portion relative to the camera, which complicates the reading process.
As a prototype of the selected device implementing the method according to the patent of Russian Federation №2309470 from 23.04.2004, IPC G21C 17/08, contained in the description to the specified patent.
The device includes illuminators and cameras with lenses that are placed in the composite annular body, with 4 cameras and 8 systems of mirrors arranged in a circle relative to the Central zone, which passes through the fuel Assembly. The entity known technical solution is to simultaneously transfer a mirror image of all fragments of the read area of the side surface along the perimeter on the camcorder, however, at least two or three of them will take the image of the flats. It does not require preliminary manipulation of the rotation of the fuel Assembly with respect to the reader.
The disadvantage is the weak security cameras from radiation, resulting in the need for frequent replacement.
The goal is to create easy-to-operate device for reading the serial numbers of FA, which design provides improved radiation protection of its sensitive the units.
The solution of this problem is provided as follows.
In the device for reading the serial numbers of fuel assemblies caused flats cylindrical surface of the shank of the fuel Assembly containing lights evenly around the perimeter covering the side surface of the shank, and mirrors to produce mirror images of all the fragments of the illuminated side surface, and also camcorders to register the received image, according to the invention the lighting and mirrors placed in the first enclosure with a through hole for the passage through it of the fuel Assembly and is provided with at least two translucent Windows in its side wall, and the mirror is installed with slope angles, providing uniform optical scan image side cylindrical surface controlled area in the plane of the translucent sealed Windows, and all the cameras are housed in a second housing that is remote from the first housing at the maximum possible distance and provided with transparent Windows facing the Windows of the first housing, and each of the cameras is configured to accept her intended part of the expanded image.
The technical result consists in the possibility to have the Alenia cameras from radiation hazard zones and compact enough of their location relative to each other in the most secure place. Compact and remote placement of the cameras is provided by the transfer deployed in the plane of the circular image on the video posted on the one hand, unlike the prototype, where video cameras placed around the circumference.
In addition, in the second case the introduced radiation-protective material, and for each camera made mirror maze, the input mirror which is converted to a corresponding input window and the output to the camcorder lens.
This provides additional radiation protection cameras in if the room's dimensions do not allow for a sufficiently large distance of one body from another, providing reliable protection.
In addition, the lighters are made in the form of elongated fluorescent lamps installed in the contact socket with replacement.
Replacement of elongated lamps can be carried out, for example, through planting holes in the top cover, closed operable plugs.
In addition, the back side of the lamp with respect to the lighted object set longitudinal screens-reflectors.
Their necessity caused by targeted use only the luminous flux of lamps for lighting readable plot.
In addition, the front side lamps have color extra long window across which the Finance colors.
This allows lighting the side surface of the light fluxes with different wavelengths at different angles, then used for analysis of the obtained color images that can increase their awareness and to ensure the accuracy of recognition with fuzzy identified characters.
Figure 1 shows a General view of the inventive device with the fragment of the optical system of the image transfer, figure 2 - three-dimensional image of the first enclosure without the top cover and side walls, figure 3 - three-dimensional image of the second enclosure without radiation protection and external walls, figure 4 - part of the first housing with the lamp-lighters.
The device comprises a first housing 1 (Fig 1, 2) with a through hole 2 for the passage of fuel assemblies (not shown) and transparent Windows 3, 4. The circumference around the through hole 2 is uniformly set illuminators 5. Mirror 6 for receiving reflected from fragments of the side surface of the fuel assemblies that are installed with different rotation angles of the images, provide a uniform transfer of the reflected mirror image in the plane of the window 3, 4, namely four neighboring fragment surface area of the fuel Assembly in the plane of each window. Part of the mirror 6 is used to transfer reflected from mirrors radiation in the plane of the window 3, 4, if it is not possible directly the th image transfer one mirror.
The second housing 7 with translucent Windows 8 is made with radiation protection 9. For convenience, the second case is made with a number of Windows equal to the number of cameras, i.e. four. Inside the housing 7 is placed video cameras, consisting of videometric 10 and lens 11 and mirror mazes formed by an input mirror 13 and the output mirror 14. The external control unit 15 and the image processing made in a clean room and is connected to the camera cable communication lines 16. The mirror maze and the fixed camera with a maximum degree of compact arrangement on the plate 16 by means of brackets 17 and 18, respectively (figure 3). The input mirror 13 is focused on the entrance window 8, the output mirror 14 in the lens 11.
Illuminators 5 made in the form of elongated fluorescent lamps, rear side equipped with screens-reflectors 19 (figure 4) and installed in the contact socket 20, 21. The upper contact of the socket are closed by removable plugs 22. Color box 23 defined by the illuminated object. Between the lamps 5 available space is blocked by the glass 24 to output reflected from the read surface of the optical radiation on the mirror 16.
The operation of the device is as follows.
Previously in the hole 2 of the housing 1 is inserted FA with shank, PA cylindrical side surface to the th performed the flats with the serial number. The need for the positioning of the fuel Assembly is missing.
Then simultaneously switched on the lights 5 and the mirror 6 are transferred image increments in azimuth of 45 degrees in the plane of the translucent Windows 3, 4. Redundancy mirror 6 is caused by the inability of the direct projection mirror image in the plane of the window 3, 4 from some sections read surface without the use of additional mirrors. Next, a detailed picture of the entire readable area of the lateral cylindrical surface through Windows 8 and mirror mazes 12 remote housing 7 is supplied to the video camera 10, 11. In a particular embodiment, for each frame of each camera is moved two images adjacent fragments of the illuminated surface. Therefore, four cameras simultaneously record the image of the entire reading surface. At least two video cameras, recording the adjacent parts of the surface, capture the image of the flats. However, the number of cameras and, accordingly, the optical systems of the image transfer may be different. The possibility of unilateral reception of optical radiation by all cameras made it possible to combine them into a single body, placing it in the most remote from the source of radioactivity. Additional protection is provided by radiation for any material 9 and the mirror maze 12.
When using colored boxes 23 each of these images is recorded together neighboring colors of the lights. Although this image of the same surface area FA, however, they differ from each other due to different angles of incidence of the radiation on the surface of the fuel assemblies. As a result, the combination of the obtained image becomes more informative. In this case, the redundancy information is used to improve the reliability of recognition of implicit symbols in the course of the subsequent image processing unit 15 by dividing the obtained color images by color illuminators, i.e. in the direction of incidence of the optical radiation in the registered area.
Thus, the proposed device allows Multiview imaging of non-SFA with remote and contactless reading rooms, ensuring maximum radiation protection for vulnerable hosts.
1. A device for reading the serial numbers of fuel assemblies caused flats cylindrical surface of the shank of the fuel Assembly containing lights evenly around the perimeter covering the side surface of the shank, and mirrors to produce mirror images of all the fragments of the illuminated side surface, and also camcorders to register the tion of the received image, characterized in that the lights and mirrors placed in the first enclosure with a through hole for the passage through it of the fuel Assembly and is provided with at least two translucent Windows in its side wall, and the mirror is installed with slope angles, providing uniform optical scan image of the lateral cylindrical surface of the controlled area in the plane of the translucent sealed boxes, and video camera are housed in a second housing that is remote from the first housing at the maximum possible distance and provided with transparent Windows facing the translucent Windows of the first housing, each of the cameras is configured to receive the corresponding part of the expanded image.
2. The device according to claim 1, characterized in that in the second case the introduced radiation-protective material and for each camera made mirror maze, the input mirror which is converted to a corresponding input window and the output to the camcorder lens.
3. The device according to claim 1, characterized in that the luminaire is made in the form of elongated fluorescent lamps installed in the contact socket with replacement.
4. The device according to claim 3, characterized in that the back side of the lamp with respect to the lighted object installations which are longitudinal screens-reflectors.
5. The device according to claim 3, characterized in that the front side lamps have color extra long window with alternating colors.
FIELD: power industry.
SUBSTANCE: invention refers to control devices of gas pressure in fuel element of reactor. Device containing annular induction heater (inductor), temperature sensors located on one side of the heater at the distance close to fuel element diametre on opposite generatrixes of fuel element cover coaxially perpendicular to fuel element axis; in order to improve accuracy characteristics of pressure measurement there additionally introduced are heat-insulation patches between temperature sensors in thermal contact zone; sensors have metal shoes in the form of rectangular copper plates bent along the radius of surface generatrix of fuel element cover, covered with electrically insulating thermally conductive film, and flexible (for example rubber) couplings; there also introduced is the device of turning the fuel element through 180° relative to its longitudinal axis together with inductor, sensors and heat-insulation patches.
EFFECT: improving accuracy measurement characteristics of gas pressure inside fuel element.
SUBSTANCE: method of controlling mass ratio of uranium-235 isotope in gaseous uranium hexafluoride involves desublimation of gaseous uranium hexafluoride in a measuring chamber by lowering temperature of the base of the chamber, determination of gamma-ray intensity of the uranium-235 isotope in the solid phase and calculation of the mass ratio of the uranium-235 isotope in uranium hexafluoride using the formula: C = α*Iγ/M, where: M is mass of uranium hexafluoride in the measuring chamber determined using a mass flowmeter or a weight measuring system, g; Iγ is gamma-ray intensity of uranium-235 in solid uranium hexafluoride in the measuring chamber, s-1; α is a calibration coefficient.
EFFECT: higher efficiency and accuracy of determining mass ratio of uranium-235 in gaseous uranium hexafluoride.
FIELD: nuclear physics.
SUBSTANCE: invention relates to operation of graphite-uranium reactors. The device for controlling the gas gap of the process channel of a graphite-uranium reactor has a calibration zirconium pipe fitted on the channel pipe of the process channel. On the outer surface of the pipe there is a block of graphite rings with fixed gaps, and a vertically movable electromagnetic radiation sensor is placed coaxially inside the pipe. The sensor is made in form of two measuring coils, compensated on the surface a uniform conducting medium, and one exciting coil above which there is a short-circuited winding made from non-magnetic current conducting material. The coils are mounted on a permalloy flat-topped magnetic conductor. The device also has a mechanism for moving the sensor and an electronic signal processing unit which is connected to the sensor and a computer. Measuring coils are accordingly connected to the electronic signal processing unit through an amplitude-phase balancing bridge circuit of the sensor, and the exciting coil is connected the electronic signal processing unit through an exciting current stabiliser.
EFFECT: more accurate control when measuring gas gaps due to possible readjustment of the sensor in the control zone.
FIELD: nuclear physics.
SUBSTANCE: invention relates to checking outward appearance of nuclear reactor fuel rods at the end of a manufacturing cycle. The device for checking outward appearance of nuclear reactor fuel rods has optical apparatus. These apparatus include at least one camera and are connected to an image reading and processing system. This system can detect presence of geometric defects on each examined fuel rod. The device additionally contains a controlled profilometer. The method of checking the outward appearance of nuclear reactor fuel rods involves two stages. Geometric defects are first detected on each examined fuel rod using optical apparatus. Right after detection of a geometrical defect, its depth is measured using the profilometer.
EFFECT: possibility of faster checking rods, since there is possibility of determining presence and depth of defects without scanning the entire surface with a profilometer.
18 cl, 6 dwg
SUBSTANCE: invention relates to the area of non-destructive testing methods. Device for automatic density determination of object (100) includes device (2) for determination of significant size x of specified object (100); device (30) for determination of photon beam intensity (I) weakened due to passing through specified object (100); device (200) for data collection, processing and analysis, transportation means (70, 72, 80, 82, 84, 86, 88) for object (100); the first regulator of (74, 76, 78) object position (100); the second regulator of (90, 92, 94, 96, 98) object position (100). Method of the above device application includes calibration stages of device (2) and device (30) and stages of actual significant size measurement for object (100), which are performed for each object (100) in specified batch of objects.
EFFECT: increase of measurement accuracy.
33 cl, 15 dwg
FIELD: nuclear power engineering.
SUBSTANCE: device for measurement of dimensions of nuclear reactor fuel elements is equipped with linear electromechanical drive with unit of automatic measurement of metering frame displacement value. Drive is fixed on the column. Device is equipped with guides with pneumatic drive for orientation of fuel assembly during loading and balloon cylinder mounted in seat-caliper, and device for generation of beams that are parallel to axis of fuel assembly represents laser units, which are installed on the foundation in boxes filled with sand, and are equipped with pendant compensators for automatic retention of beams in vertical position.
EFFECT: obtained for measurement of dimensions of nuclear reactor fuel elements.
SUBSTANCE: can be applied in burnup control of spent nuclear fuel (SNF) at the facilities storing or operating with SNF, in order to increase efficiency of SNF technological processing cycle due to the optimal configuration. During fuel burnup check fuel assemblies by gamma-ray spectrometric method burnup check process is combined with fuel assembly canisters unloading from transport. At that, fuel assembly canister is fixed, so that fuel assembly core centre is placed at the detection unit axis. Flux of gamma-ray radiation emitted by the whole fuel assembly core is passed through a collimator. Then, the flux of gamma-ray radiation is passed through dissipating filter, and photon gamma-ray radiation spectrum is measured. Peak of total energy of Cesium-137 radioactive nuclide with energy of 662 keV shows Cesium-137 content in uranium. The device for spent nuclear fuel burnup detection includes bridge crane actuator, gamma-ray dissipating filter, while collimator and detection block protection are united in a single protection monoblock. At that, the hole of the collimator is a penetration in the protection monoblock, and bridge crane actuator holds fuel assembly canister steadily against detection block.
EFFECT: fast detection of fuel burnup in fuel assemblies on industrial scale; higher efficiency of spent nuclear fuel processing and simpler construction of measurement plant.
2 cl, 4 dwg
SUBSTANCE: said utility invention relates to the instrumentation and may be used for determining parameters of bodies, mainly for remote determination of parameters of radiated fuel elements. According to the invention, for remote measurement of fuel element parameters, an empty grip is weighed and the sample held by the grip is weighed, in the air. After that, the sample and the grip are immersed in the working fluid and weighed after their immersion in the working fluid. The results are used for calculating the initial density of the working fluid. The fuel element held with the grip in the air is weighed. The fuel element with the grip are immersed in the liquid, to various depths, and weighed after each immersion. After that, the partial volume of the fuel element is calculated; the partial volume being the volume contained between the two successive cross sections of the fuel element coinciding with the surface of the working fluid in the vessel at two successive immersion stages; after that, this volume is used for calculating the average area of the fuel element cross section and the full volume of the fuel element.
EFFECT: increased accuracy of fuel element parameter determination.
FIELD: nuclear fuel production.
SUBSTANCE: proposed method for detecting surface flaws on cylindrical pieces of equipment includes sequential delivery of piece of equipment under inspection to surface inspection position. Butt-end surfaces of piece of equipment delivered to inspection position are illuminated by radiating flux. Radiation detectors receive radiation reflected from butt-end surfaces. Images received from detectors are treated in analyzing device. Side surface of piece of equipment under inspection is illuminated by radiation flux passed at angle φ to normal to its surface. Image reflected at angle to normal equal to incident angle of radiating flux is received. Butt-end surfaces of piece of equipment under inspection are illuminated by radiating flux passed at angle α to normal to butt-end surface. Radiation reflected from butt-end surfaces at angle to normal equal to incident angle of radiating flux is received. Image boundaries of piece-of-equipment surfaces are determined in image frames by means of analyzing device using boundary tracing method. Same method is used to find surface flaw sections on surface images. Surface flaws are described by geometric figures. Surface areas of these figures are calculated. Type of flaws is determined, and decision is taken on fitness of piece of equipment under inspection basing on logic decision rules.
EFFECT: enhanced reliability of on-line inspection of cylindrical pieces of equipment for surface flaws and their type.
1 cl 4 dwg
FIELD: nondestructive inspection of fissionable materials in irradiated nuclear fuel of nuclear reactor fuel assemblies.
SUBSTANCE: proposed method includes additional measurements integrated gamma-radiation in fuel assembly of geometry close to that used in recording inherent neutron radiation. Then ratio of neutron count rate (NCR) found from fuel assembly inherent neutron radiation detectors to exposure dose rate (EDR)obtained from integrated gamma-radiation detectors (NCR/EDR) is evaluated, this ratio is used to identify fuel assembly; amount of fissionable material in fuel assembly is determined by inherent neutron radiation.
EFFECT: enhanced reliability of irradiated nuclear fuel inspection with respect to inherent neutron radiation, enlarged functional capabilities due to pre-identification of fuel assembly.
1 cl, 1 dwg
FIELD: operating uranium-graphite reactors.
SUBSTANCE: proposed method for serviceability check of process-channel gas gap in graphite stacking of RBMK-1000 reactor core includes measurement of diameters of inner holes in graphite ring block and process-channel tube, exposure of zirconium tube joined with graphite rings to electromagnetic radiation, reception of differential response signal from each graphite ring and from zirconium tube, integration of signal obtained, generation of electromagnetic field components from channel and from graphite rings, separation of useful signal, and evaluation of gap by difference in amplitudes of signals arriving from internal and external graphite rings, radiation amplitude being 3 - 5 V at frequency of 2 - 7 kHz. Device implementing this method has calibrated zirconium tube installed on process channel tube and provided with axially disposed vertically moving differential vector-difference electromagnetic radiation sensor incorporating its moving mechanism, as well as electronic signal-processing unit commutated with sensor and computer; sensor has two measuring and one field coils wound on U-shaped ferrite magnetic circuit; measuring coils of sensor are differentially connected and compensated on surface of homogeneous conducting medium such as air.
EFFECT: ability of metering gas gap in any fuel cell of reactor without removing process channel.
2 cl, 9 dwg
FIELD: nuclear power engineering.
SUBSTANCE: proposed invention may be found useful for optimizing manufacturing process of dispersion-type fuel elements using granules of uranium, its alloys and compositions as nuclear fuel and also for hydraulic and other tests of models or simulators of dispersion-type fuel elements of any configuration and shape. Simulators of nuclear fuel granules of uranium and its alloys are made of quick-cutting steel alloys of following composition, mass percent: carbon, 0.73 to 1.12; manganese and silicon, maximum 0.50; chromium, 3.80 to 4.40; tungsten, 2.50 to 18.50; vanadium, 1.00 to 3.00; cobalt, maximum 0.50; molybdenum, 0 to 5.30; nickel, maximum 0.40; sulfur, maximum 0.025-0.035; phosphor, maximum 0.030; iron, the rest.
EFFECT: enhanced productivity, economic efficiency, and safety of fuel element process analyses and optimization dispensing with special shielding means.
1 cl, 3 dwg
FIELD: identifying o spent fuel assemblies with no or lost identifying characteristics for their next storage and recovery.
SUBSTANCE: identifying element is made in the form of circular clip made of metal snap ring or of two metal semi-rings of which one bears identification code in the form of intervals between longitudinal through slits. Clip is put on fuel assembly directly under bracing bushing and clip-constituting semi-rings are locked in position relative to the latter without protruding beyond its outline. For the purpose use is made of mechanical device of robot-manipulator type. Identification code is read out by means of mechanical feeler gage and sensor that responds to feeler gage displacement as it engages slits. Identifying elements are installed under each bracing bushing.
EFFECT: ability of identifying fragments of spent fuel assembly broken into separate parts before recovery.
10 cl, 4 dwg
FIELD: analyzing metals for oxygen, nitrogen, and hydrogen content including analyses of uranium dioxide for total hydrogen content.
SUBSTANCE: proposed analyzer depending for its operation on high-temperature heating of analyzed specimens has high-temperature furnace for heating uranium dioxide pellets and molybdenum evaporator; molybdenum evaporator is provided with water-cooled lead-in wire, and molybdenum deflecting screen is inserted between molybdenum evaporator and furnace housing.
EFFECT: simplified design of electrode furnace, reduced power requirement.
1 cl, 1 dwg
FIELD: the invention refers to analytical chemistry particular to determination of general hydrogen in uranium dioxide pellets.
SUBSTANCE: the installation has an electrode furnace with feeding assembly , an afterburner, a reaction tube with calcium carbide, an absorption vessel with Ilovay's reagent for absorption of acetylene, a supply unit. The afterburner of hydrogen oxidizes hydrogen to water which together with the water exuding from pellets starts reaction with carbide calcium. In result of this equivalent amount of acetylene is produced. The acetylene passing through the absorption vessel generates with Ilovay's reagent copper acietilenid which gives red color to absorption solution. According to intensity of color of absorption solution the contents of general hydrogen are determined.
EFFECT: simplifies construction of the installation, increases sensitivity and precision of determination of the contents of hydrogen in uranium dioxide pellets.
2 cl, 1 dwg
FIELD: analog computer engineering; verifying nuclear reactor reactivity meters (reactimeters).
SUBSTANCE: proposed simulator has m threshold devices, m threshold selector switches, m series-connected decade amplifiers, m electronic commutators, n - m - 1 series-connected decade frequency dividers, first group of m parallel-connected frequency selector switches, second group of n - m frequency selector switches, and group of n - m parallel-connected mode selector switches. Integrated inputs of threshold selector switches are connected to output of high-voltage amplifier and output of each threshold selector switch, to input of respective threshold device; output of each threshold device is connected to control input of respective electronic commutator; inputs of electronic commutators are connected to outputs of decade amplifiers and outputs are integrated with output of group of mode selector switches and with input of voltage-to-frequency converter; output of inverting amplifier is connected to input of first decade amplifier and to that of group of mode selector switches; input of first group of frequency selector switches is connected to output of voltage-to-frequency converter and to input of first decade frequency divider and output, to integrated outputs of first group of frequency selector switches and to input of division-chamber pulse shaper input; each of inputs of second group of frequency selector switches is connected to input of respective decade frequency divider except for last one of this group of switches whose input is connected to output of last decade frequency divider; threshold selector switches and frequency selector switches of first group, as well as m current selector switches have common operating mechanism; mode selector and frequency selector switches of second group have common operating mechanism with remaining n - m current selector switches. Such design makes it possible to realize Coulomb law relationship at all current ranges of simulator for current and frequency channels.
EFFECT: ability of verifying pulse-current input reactimeters by input signals adequate to signals coming from actual neutron detector.
2 cl, 1 dwg
FIELD: atomic industry.
SUBSTANCE: proposed line is provided with computer-aided system for contactless control of flaw depth and profile on surface of fuel element can and on end parts including sorting-out device that functions to reject faulty fuel elements. This line is characterized in high capacity and reduced labor consumption.
EFFECT: enlarged functional capabilities, improved quality of fuel elements.
1 cl, 2 dwg
FIELD: nuclear fuel technology.
SUBSTANCE: invention relates to production of pelleted fuel and consists in controlling nuclear fuel for thermal resistance involving preparation for selecting pellets from nuclear fuel lot for measuring diameter, which preparation consists in dedusting. Selected pellets are placed in temperature-stabilized box together with measuring instrument. Diameter of each pellet is them measured and measurement data are entered into computer. Thereafter, pellets are charged into heat treatment vessel, wherein pellets are heated in vacuum at residual pressure not exceeding 7·10-2 Pa at heating velocity not higher than 10°C/min to 100-160°C and held at this temperature at most 2 h, whereupon heating is continued under the same conditions to 1470-1530°C and this temperature is maintained for a period of time not exceeding 4 h, after which hydrogen is fed with flow rate 2-6 L/min. Humidity of gas mix is measured in the heat treatment outlet. If humidity of gas mixture in the heat treatment outlet exceeds 800 ppm, hydrogen feeding is stopped and material is subjected to additional vacuum degassing at residual pressure below 7·10-2 Pa and held at 1470-1530°C in vacuum for further 4 h. Hydrogen feeding is the repeated at 2-6 L/min. If humidity of gas mixture in the heat treatment outlet is below 800 ppm, preceding temperature is maintained not longer than 2 h and raised to 1625-1675°C at velocity 40-60°C/h and then to 1700-1750°C at velocity 15-45°C/h. When outlet humidity of mixture is 500-750 ppm, hydrogen feeding is lowered to 1 L/min. Temperature 1700-1750°C is maintained during 24±2 h, after which pellets are cooled to 1470-1530ºC at velocity not higher than 10°C/min. Hydrogen is replaced with argon and cooling is continued to temperature not higher than 40°C, which temperature is further maintained. Outside diameter of each pellet from the selection is measured to find average diameter of pellets before and after heat treatment in order to calculate residual sintering ability. When this parameter equals 0.0-0.4%, total lot of pellets is used in fuel elements and in case of exceeding or negative residual sintering ability the total lot of pellets is rejected.
EFFECT: improved pellet quality control.
FIELD: power engineering; evaluating burnout margin in nuclear power units.
SUBSTANCE: proposed method intended for use in VVER or RBMK, or other similar reactor units includes setting of desired operating parameters at inlet of fuel assembly, power supply to fuel assembly, variation of fuel assembly power, measurement of wall temperature of fuel element (or simulator thereof), detection of burnout moment by comparing wall temperatures at different power values of fuel assembly, evaluation of burnout margin by comparing critical heat flux and heat fluxes at rated parameters of fuel assembly, burnout being recognized by first wall temperature increase disproportional relative to power variation. Power is supplied to separate groups of fuel elements and/or separate fuel elements (or simulators thereof); this power supplied to separate groups of fuel elements and/or to separate fuel elements is varied to ensure conditions at fuel element outlet equal to those preset , where G is water flow through fuel element, kg/s; iout, iin is coolant enthalpy at fuel element outlet and inlet, respectively, kJ/kg; Nδi is power released at balanced fuel elements (or simulators thereof) where burnout is not detected, kW; n is number of balanced fuel elements; Nbrn.i is power released at fuel elements (or element) where burnout is detected; m is number of fuel elements where burnout is detected, m ≥ 1; d is fuel element diameter, mm.
EFFECT: enhanced precision of evaluating burnout margin for nuclear power plant channels.
1 cl, 2 dwg
FIELD: analytical methods in nuclear engineering.
SUBSTANCE: invention relates to analysis of fissile materials by radiation techniques and intended for on-line control of uranium hexafluoride concentration in gas streams of isotope-separation uranium processes. Control method comprises measuring, within selected time interval, intensity of gamma-emission of uranium-235, temperature, and uranium hexafluoride gas phase pressure in measuring chamber. Averaged data are processed to create uranium hexafluoride canal in measuring chamber. Thereafter, measurements are performed within a time interval composed of a series of time gaps and average values are then computed for above-indicated parameters for each time gap and measurement data for the total time interval are computed as averaged values of average values in time gaps. Intensity of gamma-emission of uranium-235, temperature, and pressure, when computing current value of mass fraction of uranium-235 isotope, are determined from averaged measurement data obtained in identical time intervals at variation in current time by a value equal to value of time gap of the time interval. Computed value of mass fraction of uranium-235 isotope is attached to current time within the time interval of measurement. Method is implemented with the aid of measuring system, which contains: measuring chamber provided with inlet and outlet connecting pipes, detection unit, and temperature and pressure sensors, connected to uranium hexafluoride gas collector over inlet connecting pipe; controller with electric pulse counters and gamma specter analyzer; signal adapters; internal information bus; and information collection, management, and processing unit. Controller is supplemented by at least three discriminators and one timer, discriminator being connected to gamma-emission detector output whereas output of each discriminator is connected to input of individual electric pulse counter, whose second input is coupled with timer output. Adapter timer output is connected to internal information bus over information exchange line. Information collection, management, and processing unit is bound to local controlling computer network over external interface network.
EFFECT: enabled quick response in case of emergency deviations of uranium hexafluoride stream concentration, reduced plant configuration rearrangement at variation in concentration of starting and commercial uranium hexafluoride, and eliminated production of substandard product.
24 cl, 5 dwg