Method of testing for compatibility of nuclear fuel powder with material of fuel element cladding
SUBSTANCE: invention relates to methods of determining compatibility of various types of nuclear fuel and structural materials. Method of testing for compatibility of nuclear fuel powder with fuel rod cladding material comprises diffusion annealing of nuclear fuel powder and fuel rod cladding pair. From material of fuel rod cladding is made crucible with a polished inner surface and lid, after which it is moulded into a powder with test fuel and fission products simulators and sealing crucible in an inert gas atmosphere, followed by annealing in temperature range of 600-1,000 °C. Testing is carried out using uranium alloy powders or uranium mononitride with particle size of 10-20 mcm. To produce crucible and cover method uses corrosion-resistant steel or zirconium alloys, and as imitators of chemically active fission products, iodine and/or caesium and/or tellurium.
EFFECT: technical result is reliable contact (adhesion) of fuel and structural materials, which increases reliability and information value of diffusion tests.
8 cl, 3 dwg
FIELD: physics, atomic power.
SUBSTANCE: invention relates to nuclear reactor fuel rods. Fuel rod cladding has an elliptical cross-section. Each nuclear fuel pellet along the longer axis of the cladding has a truncated elliptical shape, and the shorter axis of the pellet has the same length as the shorter axis of the cladding, minus the fitting gap j, wherein the difference in length of the longer axis of the cladding and the truncated longer axis of the pellet is much greater than said fitting gap j. The invention also relates to a method of making nuclear fuel pellets and a method of packing said pellets, which enables to form a fuel rod.
EFFECT: lower probability of deformation of fuel rod cladding and release of fission products into the coolant.
9 cl, 3 dwg
FIELD: machine building.
SUBSTANCE: procedure consists in immersion of tubular casing of fuel rod into water electrolytic medium containing particles of iron oxide and in covering it at least partially with layer of iron oxide. Also, particles of iron oxide are produced by anode oxidising iron containing working electrode.
EFFECT: increased corrosion resistance of treated rod and its increased service life.
7 cl, 1 dwg
FIELD: physics, nuclear.
SUBSTANCE: invention relates to nuclear power engineering and specifically to methods of making cermet rods of fuel cores of fuel elements of nuclear reactors for different purposes. A workpiece is put into a container. Working medium in form of solid glass is put into the container and the container with the workpiece and the working medium is heated to pressing temperature. The container is put into a press mould and moulding force is applied by increasing pressure of the working medium while moving the moulding die. In the proposed method the working medium is in form of a briquette. The briquette is placed at the bottom of the container. The workpiece is put on top of the briquette. The container with the workpiece and the working medium is heated outside the press mould until the workpiece is immersed in the working medium.
EFFECT: reduced probability of formation of voids, transfer of pressure onto the moulded workpiece becomes more uniform, increased output of the suitable products.
SUBSTANCE: invention is designed for increasing operation parametres and life cycle of active zone of a reactor due to the maximum fuel burnup, improved reliability and operation safety of maintenance of nuclear power stations. Fuel element can of a fast reactor with liquid metal heat carrier includes a metal tube of vanadium alloy with titanium, chrome and unavoidable impurities. External and internal tube surfaces are coated with stainless ferrite steel. Vanadium alloy components are taken at a given ratio. In particular, titanium to chrome ratio lies within 2.2 to 1.8 range. Between vanadium alloy and stainless ferrite steel a 6-8 mcm thick transition layer of solid solution of vanadium alloy with stainless ferrite steel is formed.
EFFECT: improved radiation, corrosion and heat resistance and mechanical properties of fuel element can in a fast reactor with liquid metal heat carrier.
3 cl, 5 dwg
FIELD: nuclear power engineering; nuclear reactor fuel microelements covered with four-layer shielding coating.
SUBSTANCE: proposed method involves sequential fluid-bed deposition of coating layers onto fuel microspheres. First low-density pyrocarbon layer is deposited by pyrolysis of acetylene and argon mixture of 50 volume percent concentration at temperature of 1450 °C. 85 - 95 % of second layer is deposited from high-density pyrocarbon by pyrolysis of acetylene and argon mixture of 40.0 - 43,0 volume percent concentration, and of propylene and argon mixture of 30.0 - 27.0 volume percent concentration at temperature of 1300 °C; 5 - 15 % of coating is deposited by pyrolysis of propylene and argon mixture of 5.0 - 10.0 volume percent concentration doped with 0.5 - 1. 5 volume percent of methyl trichlorosilane. Third layer of silicon carbide is deposited by pyrolysis of methyl trichlorosilane and argon mixture of 2.5 - 3.0 volume percent concentration in hydrogen-argon mixture at temperature of 1500 °C. Upon deposition this layer is treated with hydrogen at temperature of 1750 -1800 °C for 20 - 30 minutes. 90 - 95 % of fourth layer is deposited by pyrolysis of acetylene and argon mixture of 40.0 - 43.0 volume percent concentration and of argon and propylene mixture of 30.0 - 27.0 volume percent concentration at temperature of 1300 °C. Upon deposition of 90 - 95 % of fourth-layer pyrocarbon coating thickness 5 - 10 % of coating is deposited by pyrolysis of propylene and hydrogen mixture of 3.0 - 5.0 volume percent concentration.
EFFECT: enhanced service life of fuel microelements due to reduced damage probability during their manufacture and in service.
1 cl, 6 dwg, 1 tbl
FIELD: nuclear engineering, in particular, engineering of micro heat-exhausting elements for nuclear reactors.
SUBSTANCE: first layer of micro heat-exhausting element with four-layer protective cover is made of SiC-PyC composition with content of 1,0-10,0 % of mass of silicon carbide with thickness of layer equal to 0,02-0,2 of diameter of fuel micro-sphere, second layer is made of SiC-PyC composition with content of 20,0-45,0 % of mass of silicon carbide with thickness of layer equal to 0,03-0,40 diameter of fuel micro-sphere, third layer is made of silicon carbide, while fourth layer is made of titanium nitride with thickness equal to 0,01-0,08 of diameter of fuel micro-sphere.
EFFECT: increased exploitation resource of nuclear reactor due to increased corrosion resistance and radiation stability.
3 dwg, 1 tbl
FIELD: nuclear power engineering; manufacture of fuel elements and their claddings.
SUBSTANCE: each weld of cladding and its plug are tested in facility equipped with units for clamping and revolving the claddings, scanning with carriage using weld inspection piezoelectric transducer and piezoelectric transducer for measuring wall thickness in measurement region, immersion bath, ultrasonic pulse generator, ultrasonic pulse receiver, microprocessor, analog-to-digital converter switch, and random-access memory.
EFFECT: enhanced quality of fuel elements and their operating reliability in reactor core.
1 cl, 1 dwg
FIELD: nuclear power engineering; fuel rods for water-moderated water-cooled reactors.
SUBSTANCE: proposed fuel rod designed for use in water-cooled water-moderated power reactors such as type VVER-1000 reactor has fuel core disposed in cylindrical can. Outer diameter of fuel rod is chosen between 7.00 . 10-3 and 8.79 . 10-3m and fuel core diameter is between 5.82 . 10-3 and 7.32 . 10-3m and mass, between 0.93 and 1.52 kg, fuel core to fuel rod length ratio being between 0.9145 and 0.9483.
EFFECT: reduced linear heat loads and fuel rod depressurization probability, enlarged variation range of reactor power, optimal fuel utilization.
7 cl, 3 dwg
SUBSTANCE: invention relates to igniting hydrogen which is part of a gas medium. The igniter consists of a housing having openings for inlet and outlet of the gas medium, and filler in the form of bismuth oxide Bi2O3 and/or lead oxide, placed in the housing. The igniter can be used in a nuclear reactor plant.
EFFECT: obtaining a hydrogen igniter which does not contaminate the gas medium, particularly reactor cover gas, with impurities which are hazardous for installation components and/or coolant, for example, lead-bismuth coolant; removing, from the gas medium passing through the igniter, steam formed as a result of igniting hydrogen.
14 cl, 1 dwg
SUBSTANCE: method involves determination of helium pressure under cover (9) of a fuel element after its sealing, at which fuel element (1) is kept in a measurement position during the whole test period; local pulse heating of the fuel element is performed in area (4) of compensation volume; time dependence of temperature of cover sections at heating point (10) and in section (12) of the cover, which is remote from the heating point, is recorded during the whole test period. Then, helium pressure and state of the fuel element is evaluated based on it. Prior to local heating throughout the perimeter of the cover part in the compensation volume area a provision is made for elimination of heat transfer. The remote section is chosen on the other side of the compensation volume area; after that, the fuel element is exposed till its temperature is equalised with ambient temperature. Then, ambient temperature below 0°C is created; prior to local heating, the fuel element is kept till its temperature is equalised with new ambient temperature; a heating and measurement cycle is repeated with exclusion of heat transfer along the cover body from the heating point to the remote section.
EFFECT: possible testing of a fuel element on one side of a cover.
FIELD: power industry.
SUBSTANCE: invention relates to control devices of heat-producing elements (fuel elements). The method includes determination of helium pressure under the shell (11) of the heat-producing element after its sealing at which the heat-producing element (1) is sustained at the measurement position, the local pulse heating of the heat-producing element is performed in the field of the compensation volume (8), the time dependence of temperature of shell sections in the place of heating (10) is registered and on the opposite side of the shell, it is used for estimation of helium pressure and the state of the heat-producing element.. Before local heating the heat-producing element is held until equalization of its temperature with ambient temperature, and after completion of monitoring the ambient temperature below 0°C is formed, before the local heating the heat-producing element is held until equalization of its temperature with new ambient temperature, then the cycle heating-measurement is repeated and the obtained time dependences of pressure at different temperatures are compared with calibration dependences for different helium pressure and different levels of the content of air in it.
EFFECT: providing additional possibility of non-destructive control of heat-producing elements.
FIELD: testing equipment.
SUBSTANCE: in the method in process of exposure of samples of zirconium alloys in the steam and water medium in the temperature range of the light water reactor core they develop a gas discharge plasma in water vapours, afterwards they radiate samples by positively charged hydrogen ions by means of applying of negative electric potential to them relative to the plasma.
EFFECT: approximation of testing conditions of samples of zirconium alloys in steam and water medium to conditions of light water reactor core, which makes it possible to increase validity of predicted picture of behaviour of investigated zirconium alloys in light water reactor core in process of its operation made on the basis of results of these tests.
3 cl, 1 dwg
FIELD: physics, atomic power.
SUBSTANCE: invention relates to means of inspecting nuclear fuel in the form of cylindrical tablets. The apparatus for automated inspection of surface and volume defects of ceramic nuclear fuel comprises an optical image transformer, optical and thermal image recording channels, illumination sources, a system for inputting pulsed thermal flux into the inspected article and a selector which provides synchronous recording of both optical and thermal images.
EFFECT: obtaining reliable results on presence or absence of defects in inspected articles and, as a result, reliable selection of defective and non-defective articles.
7 cl, 6 dwg
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
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: 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