Ampoule device for in-reactor analysis
FIELD: power engineering.
SUBSTANCE: device comprises shell with sealing end covers to house at least one capsule with analysed specimens fitted in unsealed thin-wall shell of refractory material. Said capsule is connected with gas lines intended for streaming ventilation of capsule working space. Outlet of every line is plugged for capsule sealing, plugs being composed of sleeves with axial holes filled with fusible material. One of the lines houses thermometer transducers. Note here that sensor of every transducer is fitted inside capsule working space.
EFFECT: measurement of temperatures of emissions at nuclear disintegration during experiments, simplified design of capsule seals.
4 cl, 1 dwg
The invention relates to nuclear technology, and more particularly to a sealed irradiation devices for reactor studies of the properties of the fuel elements (Fe).
Known experimental ampoule device designed for use in reactor technology when conducting in-reactor testing of structural and fissionable materials and products from them [Gudkov L.V., goldcrests A.V. Experimental ampoule device, RF patent for the invention №2027233, IPC6G12C 17/06, publ. 20.01.1995]. Known experimental ampoule device consists of a sealed enclosure, inside of which is a capsule with samples. The gap between the capsule and the housing is filled with fusible metal alloy. In the upper part of the body is a cavity with a gas, and the internal volume of the housing is connected with otakuminopera capacity. Between the internal volume and a vacuum cavity installed frangible tube.
In the upper part of the body is a cavity with water vapor, which is designed to simulate an emergency at a nuclear reactor in case of sudden loss of coolant in the core.
Upon reaching the desired burn-in samples to signal the operator collapses the tube and the metal melt flows in otakuminopera capacity. The gap between building the som and the capsule is filled with gas. When this radial thermal resistance of the device increases by 2-3 orders of magnitude.
This could result in filling the gap between the capsule and the body of water, which is typical for emergency.
It is also known a device for irradiation of materials in a nuclear reactor [see Seredkin ST. USSR author's certificate No. 1422883, IPC7G12C 17/06, publ. 20.11.2002].
The device has an outer housing and an ampoule with the sample separated from the outer casing of the gas gap. A device for irradiation of materials in a nuclear reactor designed to increase the performance of the experiment while maintaining the automatic temperature control of the samples. To address this goal cylindrical outer casing is connected to the ampoule by a ring of bumps made of bimetal, and the outer body has a longitudinal corrugations. The disadvantage of this device is that the outer housing can be located only one ampoule that is not possible in a single experiment to irradiate several different fuel element materials in the same conditions.
Closest to the claimed technical solution to the problem at hand and the technical result is a sealed device for reactor research; cited in Wassilewskija "Methods and means of experimental IP the studies and reactor testing thermal emission electricity generating Assembly. M.: Energoatomizdat, 2000, s.112. This technical solution according to the number of matching essential attributes selected as a prototype.
Known ampoule device is intended for studying of free swelling and joint sweling system fuel-shell and consists of a high temperature capsule cylindrical shape, within which is placed the sample, covered with a refractory metal. The capsule is equipped with a gas line for filling with inert gases. At the exit of the highway pneumatic valves for sealing the capsules. The capsule is placed in a stainless steel shell with a radial gap filled with inert gas with different conductivity.
Capsule sealed device with sensors neutron flux and temperature. Ampoule device can irradiate the samples with heat dissipation 60÷240 W/cm3and temperature on shell samples 1600-2200 K. Ampoule device is instrumented and allows you to adjust the irradiation parameters in the tests.
However, this solution has several disadvantages:
- does not allow to analyze in the course of the experiment gaseous fission products (GPA)released during nuclear decay;
- not possible to measure the temperature of the sample during the experiment;
- sealing work is her oral ampoule device is pneumatic valves, what complicates the design and technology of manufacture of the device, in addition, the process of depressurization occurs under the influence of high pressure on the operating element of the valve, which implies the presence in the test bench of additional equipment, such as gas high-pressure line.
Task to be solved by the present invention is directed, is the creation of a sealed device for reactor research, allowing to measure the temperature of the samples during the experiment, analysis GPA released during nuclear decay during the experiment, to have a simple design and technological point of view, the mechanisms of the temporary sealing of the working cavity.
The task and the technical result is achieved by the fact that the ampoule device for reactor research, including a shell with a sealing end caps, inside which there is at least one capsule, with the test sample placed in non-vacuum thin-walled shell of refractory material according to the invention the capsule is supplied in addition to a gas line additional line with the possibility of flow-through ventilation of the working cavity of the capsule, at the output of each line set stubs for temporary hermeti the emission capsules, made in the form of a bushing with an axial hole filled with fusible material, thermometric sensors enclosed in sealed covers, are located in one of the highways, with the sensing element of each sensor is introduced into the working cavity of the capsule.
Tight connection of the capsule shell ampoule device can be realized by means of the bellows is placed in one of the highways.
In the private embodiment, the sleeve is located in line with thermometric sensors can be provided for axial holes for placing covers thermometric sensors, sealed with the sleeve by means of soldered connections.
Ampoule device may be further provided with a heat radiator installed inside with a gap coaxial shell ampoule device, the heat sink is made of axial holes located around the circumference at the same axial distance from the end face of the radiator to install the capsules with the test samples.
Introduction the ampoule device additional line allows you to analyze the experiment gaseous fission products (GPA)released during nuclear decay, due to the flow-through ventilation of the working cavity of the capsule, which provides t is unsportive GPA to analyzing the bench reactor.
The location of sensitive elements thermometric sensors in the working cavity of the capsule allows you to measure in the experiment, the temperature of the sample.
The design of the plugs for temporary sealing of the working cavity of the capsule in the form of a bushing with an axial hole filled with fusible material, simplifies the manufacturing technology of the plugs. In addition, this design simplifies the process of depressurization of the working cavity of the capsule, without the need to create in the arteries high blood pressure.
The presence in the design ampoule device heat sink, in the axial holes which are installed capsules at the same axial distance from the end face of the heat sink (respectively at the same level of the reactor core), simultaneously in the same conditions to test multiple samples in offline capsules.
The essence of the claimed invention is illustrated by the drawing, which schematically depicts the design of the ampoule device.
Ampoule device consists of a cylindrical shell (1) with two end sealing caps (2, 3), a cylindrical heat sink (4)that is installed inside the shell (1) coaxial with the last gap for optimal heat dissipation. In the axial hole at back is the second radiator (4), made on the same axial distance from the end face of the radiator, are the capsules (5) stainless steel. Each capsule includes the investigated fuel sample (6), enclosed in a thin-walled shell (7) of the refractory material. Each capsule is hermetically coupled to gas pipelines (8, 9) and shell (1) ampoule device with bellows (10)installed in one of the gas lines. At the exit of the gas lines installed caps (11, 12)made in the form of sleeves (13, 14). The sleeve (13) has an axial hole (15, 16) for installation of temperature sensors and a hole (17) for passage of gases. The sleeve (14) is also provided with a hole (18) for passage of gases. Holes (17, 18) filled with solder of the fusible material. Sealed pouches (19, 20) sensors mounted in the axial hole (15, 16) and is hermetically coupled to the sleeve (13)and the sensor elements (21) sensors introduced into the working cavity (22) of the capsule (5). In addition, in the capsule provided by Belleville springs (23), spacer (24), guide sleeve (25).
The drawing shows a variant of the ampoule device with three capsules mounted in the axial holes of the heat sink, which is made on the same axial distance from the end face of the radiator, which gives the opportunity to test samples under the same flux is Oh neutrons in the reactor. However, the capsules may be a different number.
The proposed ampoule device is as follows. Ampoule device, which consists of one or more capsules with a test sample rods, attached to the gas communications reactor. When this advance is the inert gas filling the working cavity of the capsules, which are analyzed samples of the fuel rods, the temporary sealing it with fusible material of the plugs. The sensitive elements of sensors located in a hermetically introduced into the cavity of the samples covers, wind up in the gas line capsules. Connection ampoule device with a gas communications reactor is carried out by welding. After gas pipeline ampoule device will be sealed, is the destruction of the fusible material of the plugs due to the heating of location and create a pressure difference in the right direction. Next, the entire Assembly is installed in the cell of the reactor.
When the output of a nominal mode, the sample (6) is in contact with the thin-walled shell (7) due to thermal expansion. Thin-walled shell pattern allows it to expand freely. To compensate for axial expansion of the sample provided by arelative spring (23). However, the thin-walled shell (7) and the shell of the capsule (5) there remains a gap for passage of gases.
The system allows you to adjust the conditions of heat transfer from the surface of the fuel rods to the coolant (water) through changes in the composition of the gas in the gap between the thin-walled shell (7) and the shell of the capsule (5).
An example of a specific implementation.
The design ampoule device for testing fuel samples UN in the reactor TRS-2M.
Ampoule device comprises a shell made of stainless steel with a thickness of 1 mm and a diameter of 54 mm, two end caps with holes for gas lines, cylindrical aluminum radiator made it three axial holes, which are capsules. Each capsule has a shell made of stainless steel with a thickness of 1 mm, which with a gap of 200 μm is placed investigated the fuel sample in a thin-walled shell, two end caps with tightly attached gas pipelines of stainless steel. Fuel sample with a diameter of 8 mm and a length of 35 mm mounted in thin-walled shell of a single crystal of tungsten with a thickness of 0.3 mm with a gap of 30 μm. One of the sensors is introduced in the fuel sample. The second sensor is located outside of the sample, in contact with the casing through a spacer made of molybdenum and is used to control the temperature of thin-walled shell of the investigated sample. In each gas line installed sleeve with an axial hole with a diameter of 22 mm, filled with fusible solder POS for temporary sealing of the capsule. And one of the sleeves has two additional holes of 2 mm diameter, which are soldered covers sensors, made of molybdenum. Shell capsules connected with the shell ampoule device through the bellows of stainless steel. To compensate for axial expansion of the investigated fuel sample introduced Belleville springs alloy BP-27.
The design of the ampoule device allows complete Assembly in the absence of contact of the sample with oxygen.
The system enables the transport of gaseous fission products to analyze the stand of the reactor through the implementation of flow-through ventilation of the working cavity of the capsule through the gas pipeline. This gives the opportunity to analyze released in the course of the experiment GPA.
Ampoule device simultaneously under identical conditions to test multiple samples in offline capsules located in the heat sink on the same axial distance from the end face of the heat sink, respectively - at the same level of the reactor core.
After finishing the test when conducting post-irradiation studies of capsules direct Redstone measurement of the geometry of the samples will allow us to estimate the change in the size of the specific irradiation conditions.
1. Ampoule device for reactor research, including a shell with a sealing end caps, inside which there is at least one capsule with a test sample placed in non-vacuum thin-walled shell of refractory material, while the capsule is equipped with thermometric sensors enclosed in sealed covers, and is connected with a gas line, wherein the capsule is provided with an additional gas line with the possibility of flow-through ventilation of the working cavity of the capsule, at the output of each line set stubs for temporary sealing of the capsule is made in the form of a bushing with an axial hole filled with fusible material, thermometric sensors are located in one of the highways, while the sensing element of each sensor is introduced into the working cavity of the capsule.
2. Ampoule device according to claim 1, characterized in that the capsule is hermetically coupled to the ampoule shell device with bellows placed in one of the highways.
3. Ampoule device according to claim 1, characterized in that the sleeve is located in line with thermometric sensors, equipped with an additional axial holes for placing covers thermometric sensors, sealed with the sleeve by means of solder is soedineniya.
4. Ampoule device according to claim 1, characterized in that it further provided with a heat radiator installed inside with a gap coaxial shell ampoule device, the heat sink is made of axial holes located around the circumference at the same axial distance from the end face of the radiator to install the capsules with the test samples.
SUBSTANCE: fuel element simulator has a shell in which there is a column of natural fuel tablets with a centre hole, and an electric heater placed with clearance in the holes of the tablets. The heater is in form of pipe made of heat-resistant material on the outer surface of which is formed a microrelief which varies on the length of the heater and which provides optically variable properties on the length of the surface, which correspond to the simulated temperature profile. A shielding pipe made of heat-resistant material is also placed with clearance on the outside coaxial to the shell, the inner and outer surfaces of said pipe also having a varying microrelief which provides optically variable properties on the length of the heater.
EFFECT: high accuracy of simulating the thermal state of fuel elements under investigation by obtaining temperature levels, thermal flux and temperature profiles similar to those in full-scale conditions.
7 cl, 2 dwg
FIELD: power engineering.
SUBSTANCE: device arranged on a stand (4), comprises a place (31) with a horizontal axis (X) for placement of the above fuel rod; a facility (20) for measurement of deviation from parallelism and a facility (22) for correction of the above deviation. The device comprises a facility (14) of device positioning relative to the fuel rod comprising two parallel supports arranged at the distance from each other, at the same time each of them supports the end of the above fuel rod. The supports are made in the form of two horseshoe-shaped parts (16.1. 16.2), the inner ends of which are designed for resting against the fuel rod, and are distanced from each other at the specified distance to ensure the coverage of the stand support, at which the end rests with the upper plug of the fuel rod, and which has thickness that is substantially equal to the distance between two horseshoe-shaped parts (16.1, 16.2). Also the device comprises a facility (32) to retain a fuel rod made as capable of providing for rotation of the fuel rod around its longitudinal axis, which is arranged between the facility (14) of positioning and facilities of measurement and correction. The facility (32) comprises a lower grip (34) and an upper grip (36), to hold the fuel rod, at the same time the lower grip (34) forms a base for measurement of deviation from parallelism.
EFFECT: provision of measurement of deviation from parallelism during correction of the above deviation.
12 cl, 15 dwg
FIELD: power industry.
SUBSTANCE: specimen is made of two coaxially combined tubular elements; one of which is fully or partially located inside the other one; gas pressure is created in a cavity between elements, sealed, arranged in a nuclear reactor and irradiated.
EFFECT: increasing informativity and reliability of results of change of properties of reactor materials at irradiation in the reactor at various types of stress-and-strain state.
3 cl, 1 dwg
FIELD: power engineering.
SUBSTANCE: time-series data by reactivity is produced from time-series data by a neutron bundle by the method of reverse dynamic characteristic in respect to a single-point kinetic equation of the reactor. Time-series data by fuel temperature exposed to previously determined averaging is produced using time-series data by power output of the reactor and pre-determined dynamic model. The component of contribution to feedback by reactivity is determined using time-series data by reactivity and introduced reactivity. The Doppler coefficient of reactivity is determined using the received time-series data by average temperature of a moderator in the reactor, time-series data by fuel temperature exposed to previously determined averaging, isothermic temperature coefficient of reactivity and component of contribution to feedback by reactivity.
EFFECT: increased accuracy and simplicity of measurements of the Doppler coefficient and possibility of its usage in case of use of discrete data.
8 cl, 7 dwg
FIELD: power industry.
SUBSTANCE: nuclear fuel pellet density monitoring plant includes measuring unit including gamma radiation source and detection unit, transfer mechanism for movement of pellets and hold-down device, as well as measuring result control and processing unit intended to control the operation of transfer mechanism for processing of measuring results and rejection of pellets. Transfer mechanism includes the first transfer assembly for movement of column of pellets through measuring assembly with reference to outlet pallet, the second transfer assembly for movement of reference and outlet pallet for columns of pellets in transverse direction, and hold-down device has the possibility of pressing the pellets during movement of column of pellets through the measuring unit.
EFFECT: invention allows increasing the monitoring efficiency due to supply to monitoring zone of nuclear fuel pellets in the form of columns and performance of measurement during movement of columns through the monitoring zone.
2 cl, 1 dwg
FIELD: power engineering.
SUBSTANCE: method of creep-rupture test of tubular samples in a non-instrumentation channel of a nuclear reactor includes the following operations. At least one reference tubular sample loaded with inert gas pressure is placed into a heating furnace, maintained at the preset temperature in the heating furnace until destroyed, and time is measured to the moment of its destruction. Two tubular sample accordingly loaded and non-loaded with inert gas pressure are simultaneously placed into an ampoule. The tight ampoule with both types of tubular samples is radiated in a nuclear reactor channel. The radiated tubular samples are placed into a heating furnace and tested until destroyed under pressures and temperatures similar to the ones in the reactor. The time is measured to the moment of destruction of tubular samples of the first and second types in the heating furnace. The time to the moment of tubular sample destruction under conditions of reactor radiation at the preset pressure and temperature is determined using the ratio that takes into account time values measured in process of method realisation.
EFFECT: invention makes it possible to increase accuracy of detection of strength characteristics of materials.
FIELD: power engineering.
SUBSTANCE: device to pelletise nuclear fuel comprises press, conveyor (4) for transportation of pellets from press to sintering area, facility (26) of pellets reloading from press to conveyor (4) and facility of inspection of at least one pellet of nuclear fuel at the outlet of press, besides, facility of inspection comprises facility for detection of matrix, where each pellet is made. Method to manufacture pellets of nuclear fuel with application of device, which includes stages, when matrices (10) are filled with powder, powder is pressed, pellets (P) are reloaded to conveyor (4), conveyor (4) is started, pellet (P) is taken, manufactured in certain matrix (10), proper operation of this matrix is inspected by results of inspection of pellets manufactured in it, pellets (P) are transported to sintering area.
EFFECT: control of manufactured pellets density, control of pellets without increasing duration of production cycle.
24 cl, 4 dwg
FIELD: power industry.
SUBSTANCE: control method of gas pressure in fuel element of nuclear reactor consists in the fact that fuel element is located horizontally, inserted in annular induction heater, heat impulse is generated, which induces convective gas current in fuel element, change of temperature is measured with temperature sensors pressed to the cover and gas pressure is calculated on the basis of temperature change value; at that, shoes and couplings are installed on temperature sensors prior to measurements; sensors are pressed to the cover opposite to each other, one is from above, the other is from below, heat-insulating patches are installed between sensors and difference of temperatures shown with sensors is measured, then heat impulse is supplied and difference of temperatures is measured again in certain time τ1; after that, fuel element is turned together with patches, sensors and induction heater through 180° and after it is turned, temperature difference is measured in certain time τ2, then the second heat impulse is supplied and temperature difference is measured again in time τ1; then fuel element is turned together with patches, temperature sensors and induction heater through 180° back to initial position; then temperature difference is measured again in time τ2; cycle is repeated for several times; after that obtained results are mathematically processed, and as a result gas pressure value is determined inside fuel element.
EFFECT: improving measurement accuracy of gas pressure inside fuel element.
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
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.
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