RU2229749C2 - Method for injecting fusionable fuel in vacuum chamber of thermonuclear reactor - Google Patents

Abstract

FIELD: devices for fuel injection in thermonuclear installation plasma. SUBSTANCE: method involves production of fusionable fuel macroelements by placing fusionable fuel in sealed metal capsules which are shot from pneumatic or fire arms into hole in vacuum chamber wall of thermonuclear reactor meant for fuel injection in sighting and remote, single-shot or repetitive manner to ensure cumulative penetration of fusionable fuel into vacuum chamber in vicinity of pinch. Shooting may be made through obstacle installed near vacuum chamber that has hole coaxial in capsule flight path with hole in vacuum chamber; metal body of capsule seizes in obstacle hole and capsule content penetrates into chamber through its hole. Provision is made for varying capsule speed within about 0.7 to 2.5 km/s and for varying distance between arms and vacuum chamber. EFFECT: provision for dispensing with vacuum channel between injector and vacuum chamber. 1 cl, 2 dwg

Description

The invention relates to controlled thermonuclear fusion (TCB) and is intended for use in devices for introducing fuel into the plasma of thermonuclear installations.

For long-term maintenance of the thermonuclear reaction in nuclear fusion plants, and in particular, tokamak plants, it is necessary to refuel the vacuum chamber with thermonuclear fuel during discharge. The fuel used is one of the heavy hydrogen isotopes or a mixture of such isotopes. The fuel injection must be carried out with a high speed (500-1500 m / s) and a mass sufficient for fuel to penetrate into the central region of the plasma cord, as well as with a frequency (5-50 Hz), which provides the necessary time for continuous operation of the installation. The specific values of these parameters depend on the size of the plants. Fuel can be supplied to the reaction zone in the form of gas jets, liquid jets, solid tablets, as well as in the form of neutral particles and plasma clots.

Known light gas injector of fuel particles for thermonuclear installations, containing located in the vacuum path of the barrel, a sleeve cooled by a helium heat exchanger, a system for supplying an accelerating gas to the barrel with a pulse valve, a fuel gas inlet system, in particular hydrogen, a heat-conducting porous sleeve located inside the cooled sleeve, a synchronization system, a differential pumping system and other elements (AS USSR No. 1611139, G 21 B 1/00, decl. 03.04.89, publ. 27.05.97, Bull. No. 15). This injector implements a gas injection method comprising three stages: the stage of cooling gaseous hydrogen to freezing; the stage of formation of the particulate by heating hydrogen to 14 K and its accumulation in a porous sleeve with further constant and intensive cooling to complete freezing of the liquid particulate; and a step of accelerating the particulate by supplying gas accelerating the particulate to the barrel. Fuel gas - hydrogen is supplied at a pressure of 60 Torr through a porous bushing into the barrel with a flow rate of 2.7 mg / s, corresponding to the fuel consumption during injection into the tokamak of particulate matter with a diameter of 2 mm, a length of 2 mm and a frequency of 5 Hz.

This type of injection and injector of this type is widely used in some experimental tokamak installations, however, for large installations with a plasma cord diameter of more than 2 m, it does not provide the necessary speed (up to 1000 m / s) and frequency (up to 50 Hz).

Based on the light gas gun, the TPI-1 tritium particulate injector was developed for introducing fuel into thermonuclear reactors. In the breech of a light-gas gun in a nitrogen-helium jellied cryostat at a temperature of 10-20 K, 1 to 50 particles of solid tritium 4 mm in size are formed. Under the action of compressed light gas, the particle accelerates to 1-1.2 km / s in the barrel. The injector also includes a system for the preparation and supply of tritium and deuterium, a diagnostic chamber, a vacuum system, a data acquisition and control system (G.A.Baranov, I.V. Vinyar, P.Yu. Koblents and others. Injector of tritium particles TPI- 1. - Abstracts of the sixth All-Russian Conference on Engineering Problems of Thermonuclear Reactors, St. Petersburg, May 27-29, 1997. - M .: Central Research Institute of Management, Economics and Information of the Ministry of Atomic Energy of the Russian Federation, 1997, p.148). In the injector project proposed for the ITER international reactor, based on this development, it is planned to achieve a speed of 1000 m / s and a frequency of 50 Hz for the injection of tablets with a diameter of 3-7 mm.

Known two-stage injector of thermonuclear fuel tablets, containing a vacuum chamber with a barrel, at the beginning of which is installed a cell of the tablet former, connected to the heat exchanger, a pipe of the second stage with a valve for introducing gas, a piston that can be moved inside the pipe of the second stage, a valve to fill the tank of the first stage diagnostic camera; the inner cavity of the cell of the tablet former is made in the form of a truncated cone, the axis of which coincides with the axis of the barrel. (RF patent No. 2132577, G 21 B 1/00, application. 11.02.97, publ. 06/27/99, Bull. No. 18). In this injector, gaseous fuel (hydrogen) is cooled by a liquid-helium heat exchanger in the cell of the tablet former to a temperature of about 10 K, a tablet is formed inside the conical opening of the cell where hydrogen freezes. The injection process begins with the arrival of an accelerating gas (hydrogen, helium) at a pressure of 6-10 MPa, which accelerates the piston and compresses the fuel gas in front of it, and hydrogen, whose pressure from the initial 0.01-0.05 MPa has increased to 10 MPa begins to be extruded through the conical opening of the cell into the barrel and further into the plasma of the fusion plant. The mode of operation of the injector valves is selected so that the piston does not have time to push all the gas into the barrel, but is inhibited by the pressure of this gas and bounces to its original state.

In this injector, the tablet begins to accelerate in the barrel at a higher initial gas pressure, which increases the rate of injection and the depth of penetration of fuel into the plasma, which allows maintaining a stable thermonuclear reaction in the central zones of the plasma. The disadvantage is the presence in the design of the injector of a moving element, which reduces the reliability. The complexity of adjusting the operation of the injector valves, on which the entire process of its operation depends, is its other drawback.

A type of two-stage injector is an experimentally studied pellet injector with liner compression of pushing gas, in which instead of a piston, a cylindrical aluminum liner is used to compress the gas pushing the tablet, accelerated by electromagnetic forces due to the passage of current through the liner, which is powered by a capacitor bank; the calculated speed of the plastic tablet is 4.6 km / s, deuterium 10 km / s with a diameter and length of the tablet 2 mm, the measured speed of the plastic tablet was 2.5 km / s (V.P. Bazilevsky, Yu.A. Kareev, A .I. Kolchenko et al. Pellet injector with liner compression of pushing gas. / Abstracts of the Sixth All-Russian Conference on Engineering Problems of Thermonuclear Reactors. - St. Petersburg, May 27-29, 1997. - M. Central Research Institute of Management, Economics and Information of the Ministry of Atomic Energy RF, 1997, p. 155).

The disadvantage of this method of acceleration of the piston (liner) is the implementation complexity associated with the need to use expensive and energy-intensive equipment.

Known high-speed system for injection of cryogenic tablets, containing a pneumatic two-stage system for feeding tablets; at the first stage, high-pressure gas enters the piston, which adiabatically compresses the moving gas through the high-speed control valve in the second stage; a peak pressure of about 200 MPa for 10-100 μs is created in the barrel for starting the tablet (US patent No. 5406594, G 21 B 1/00, decl. 17.07.91, publ. 11.04.95; ISM issue 099, 1996, No. 5 , p.13).

This system has a common element with a two-stage injector according to the patent of the Russian Federation No. 2132577 - a piston and a higher pressure in the barrel is achieved in it. However, the presence of a moving element reduces the reliability of the system.

A device for injecting twice accelerated tablets is known, in which an injector such as a gas gun shoots a tablet accelerated during expansion of the accelerating gas into a gap between two guides equal to the diameter of the guide tube to prevent destruction of the tablet; an electric discharge is initiated behind a tablet in an accelerating gas by a laser beam and a plasma is generated that additionally accelerates the tablet (Japanese Patent No. 2737055B2, G 21 B 1/00, application. 17.10.88, publ. 08.04.98; ISM issue 099, 1999, No. 5, p. 3).

Preserving the integrity of the tablet eliminates the appearance of plasma in front of the tablet, which allows for additional acceleration to inform the tablet high speed. However, the implementation of such a device requires expensive and energy-intensive equipment.

Known pellet injector for a thermonuclear installation JET, made on the principle of a centrifuge. This centrifugal device, designed to throw single tablets formed of hydrogen at cryogenic temperatures into a plasma, contains a rotor in the form of a rod located in the vacuum chamber of the injector and connected to the drive shaft; on the side surface of the rod there is a radial accelerating channel having a conical section with a large base open to the cavity of the vacuum chamber; in the upper part of the chamber there is a cryogenic extruder of tablets with a mechanism for feeding them into an outlet tube placed perpendicular to the plane of rotation of the accelerating channel; using a feeding mechanism, a tablet of hydrogen is supplied to the accelerating channel, captured by it, accelerated and thrown out on the periphery of the rotor into a pipeline connecting the vacuum chamber of the injector to the vacuum chamber of the thermonuclear installation in which the plasma is burning (Andelfinger C., B.uchl et al. ., Pellet Injectors for JET. - IPP, 1/193, Sept. 1981, Max-Planck Institute for Plasmaphysik).

The method of feeding a tablet to the accelerating channel used in this device by capturing it by this channel when moving the tablet in a direction perpendicular to the channel requires tight synchronization of the rotor speed and the tablet speed, which complicates the operation control system and the supply reliability. In addition, the feed of the tablet into the conical accelerating channel is associated with the uncertainty of the contact point between the tablet and the channel, which reduces the accuracy of the tablet entering the connecting pipe and increases the likelihood of tablet loss in the cavity of the injector chamber.

A known method of supplying a tablet to the accelerating channel of the rotor of the particulate injector by moving the tablet perpendicular to the radial accelerating channel, according to which the tablet is first moved perpendicular to the accelerating channel, then it is captured by the rotor, is moved in the radial and circumferential directions, is thrown tangentially from the rotor into the plane of the accelerating channel, after what catch the tablet accelerating the channel of the rotor (AS USSR No. 1258223, G 21 B 1/00, decl. 17.12.84, publ. 06.04.87, Bull. No. 12, p. 281). A device for supplying a tablet to an accelerating channel of a rotor of a particle injector for implementing this method comprises a tablet extruder with an output tube mounted on a housing in which a rotor with a radial accelerating channel is located on the side surface, as well as a hollow cylinder mounted on the housing with an end gap relative to the plane of the rotor , which is located in the plane of the axis of symmetry of the accelerating channel, the output tube of the extruder is placed inside a hollow cylinder, in which a radial outlet e and the rotor plane are arranged on the radial ribs with a clearance relative to the cylinder.

This method and device eliminates the disadvantages of the centrifugal device described above, but they have their drawbacks, namely: elastic rebound of the cryogenic solid-hydrogen tablet from the wall of the stationary cylinder is possible due to its evaporation upon contact with the “warm” cylinder, which prevents the capture of the next tablet and reduces the capture frequency pills the elastic rebound of the tablet at the time of its exit through the window of the stationary cylinder leads to instability of its departure and an increase in the scattering angle; an increase in the scattering angle at the exit from the stationary cylinder leads to a change in the capture point of the tablet by the main accelerating channel and, therefore, to an increase in the scattering angle of the tablet at the exit of the centrifuge, which leads to additional loss of mass and speed of the tablet during its passage through the pipeline to the plasma of the thermonuclear installation.

From the above methods and devices for thermonuclear fuel injection, the gas injection method used in the two-stage injector according to the patent of the Russian Federation No. 2132577 was selected as the prototype. The gas injection method, which has found the widest application in existing and planned toroidal thermonuclear installations and which allows achieving the necessary injection parameters for large installations includes three stages carried out in a vacuum: the stage of cooling gaseous fuel hydrogen with a liquid-helium heat exchanger; the stage of formation of tablets from frozen hydrogen and the two-stage stage of acceleration of the tablet under the action of an accelerating gas (hydrogen or helium) using additional compression of the fuel gas using a piston.

The disadvantages of this method are the difficulty of implementation, work with only one form of fuel condition (frozen tablets), the need to work in a vacuum of the injector itself, and the presence of a vacuum path between the injector and the vacuum chamber.

The claimed invention is aimed at solving the problem of creating a simpler method of injection of thermonuclear fuel into the vacuum chamber of thermonuclear reactors, satisfying the requirements for the injection parameters necessary for demonstration tokamak thermonuclear reactors, in which it is possible to work both with solid fuel pellets and with the gaseous and liquid state of the thermonuclear fuel.

The essence of the invention consists in a method of injection of thermonuclear fuel into the vacuum chamber of a thermonuclear reactor, which consists in the formation of macronutrients with thermonuclear fuel, acceleration of these macronutrients by the action of gas and the introduction of thermonuclear fuel in a vacuum chamber. In this method, thermonuclear fuel macroelements are formed by placing thermonuclear fuel in metal sealed capsules, which are aimed and remotely, singly, or in bursts fired from a pneumatic or firearm into a hole in the wall region of the thermonuclear reactor's vacuum chamber allotted for fuel injection, providing for cumulative penetration of the thermonuclear fuel inside the vacuum chamber into the plasma cord region. In the particular case of the invention, targeted shooting into the hole of the vacuum chamber can be conducted through an obstacle located near the vacuum chamber, having a hole coaxial along the path of the capsule with the hole in the vacuum chamber, while the metal capsule body in the hole of the obstacle is stuck, and the contents of the capsule through the hole in the vacuum chamber penetrates into it.

The technical result that can be obtained by carrying out the invention is the absence of a vacuum path connecting the injector to the vacuum chamber of the reactor, and the possibility of varying the capsule's flight speed depending on the type of weapon within ~ (0.7-2.5) km / s , which, at a minimum, will correspond to the speed of the cumulative jet, in the possibility of changing over a wide range of distances from the weapon to the vacuum chamber, given the size of its radiation protection.

The method is illustrated in the drawing, where Fig. 1 shows a schematic representation of a device for injecting a thermonuclear reactor into a vacuum chamber, and Fig. 2 shows a fragment of a wall of a vacuum chamber with an opening into which a thermonuclear fuel is thrown.

The injection method is as follows. At a special site, the formation of macronutrients is performed. Thermonuclear fuel (deuterium or tritium or a mixture of deuterium and tritium) in the form of a gas, liquid or frozen tablet is placed in lead capsules, which are rolled in the form of bullets. Tablets (pellets) are made using conventional extruders and cryogenic devices are needed to store them. At a selected distance from the vacuum chamber of the fusion reactor, weapons are mounted. Depending on the required flight speed of the bullet capsule, a small-caliber rifle, a conventional rifle or carbine, an automatic rifle or a conventional air gun (airgun), which can be equipped with an optical sight, can be used. The weapon is aimed at the hole in the injection area of the vacuum chamber of the thermonuclear reactor and is rigidly fixed. It is advisable to carry out the shooting using the device depicted in figure 1. On the massive base 1, fixed on the foundation between the weapon and the vacuum chamber of the thermonuclear reactor, an obstacle 2 is set in the form of a massive metal body in which a through hole 5 is made on the axis of the flight path of the capsule 3 with thermonuclear fuel 4 with a funnel-shaped entrance from the capsule approach side. The hole 6 on the vacuum chamber 7 of the thermonuclear reactor is performed with a funnel-shaped inlet on the outer surface of the vacuum chamber, where the aiming is carried out (figure 2). The diameter of the hole 5 on the obstacle 2 is approximately equal to 1.5 mm, and the diameter of the hole 6 in the vacuum chamber 7 is approximately equal to 1-1.5 mm based on the size of the capsule, which contains a sufficient amount of thermonuclear fuel for single injection. The obstacle 2 captures the capsule 3 when approaching and delays in the funnel-shaped part of the hole 5 the metal part of the capsule, and its contents, i.e. thermonuclear fuel flies into the funnel-shaped part of the hole 6 in the vacuum chamber 7 and through this hole cumulatively penetrates into the vacuum chamber 7 of the thermonuclear reactor. In order to maintain the vacuum conditions in the vacuum chamber, a conventional aperture can be installed in the hole 6 according to the type of aperture of a camera with a synchronization system with a shot. The diaphragm opens when the pellet passes through the hole 6 in the vacuum chamber 7 of the thermonuclear reactor. The hole 6 can also be made in the form of spring petals, opening with the help of an incoming jet of fuel and closing after it passes almost without breaking the vacuum in the chamber 7. The capsule-bullet 3 is braked about an obstacle 2 in front of the vacuum chamber 7 in the receiving device (cone of the funnel-shaped inlet of the opening 5 ), and a stream of liquid (gas) flies further into the guiding device (cone of the funnel-shaped inlet of the opening 6) of the vacuum chamber 7 of the thermonuclear reactor. The bullet is removed from the receiving device, for example, using its usual extension. In this case, the obstacle 2 is made of two halves with springs between them.

Claims (2)

1. The method of injection of thermonuclear fuel into the vacuum chamber of a thermonuclear reactor, which consists in the formation of macronutrients with thermonuclear fuel, acceleration of these macronutrients by gas and the introduction of thermonuclear fuel into a vacuum chamber, characterized in that the macronutrients with thermonuclear fuel are formed by placing thermonuclear fuel in metal sealed capsules that are aimed and remotely, singly or in bursts, from airguns or firearms into the hole in the area wall of a fusion reactor vacuum chamber allocated to the fuel injection providing the cumulative penetration thermonuclear fuel inside the vacuum chamber to the plasma column. 2. The injection method according to claim 1, characterized in that the targeted shooting into the hole of the vacuum chamber is conducted through an obstacle installed near the vacuum chamber, having a hole coaxial along the flight path of the capsule to the hole in the vacuum chamber, while the metal capsule body in the hole of the obstacle is stuck , and the contents of the capsule through the hole in the vacuum chamber penetrates into it.

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