RU2245004C2 - Central solenoid for resistive plasma heating - Google Patents

Abstract

FIELD: plasma physics and controlled nuclear fusion problem.

SUBSTANCE: proposed central solenoid used as tokamak inductor and easily dismounted from central column has four conductor layers with inner cooling ducts. Each layer is made separately with four entrances in each layer. All sixteen conductors are connected in series and their junctions are disposed on butt-end surfaces of solenoid switching blocks. Insulated layers of conductors are inserted one into other.

EFFECT: reduced operating loads, enhanced uniformity of magnetic field.

1 cl, 1 dwg

Description

The invention relates to techniques related to plasma physics and the problem of controlled nuclear fusion, and is used as a tokamak inductor.

The central ohmic heating solenoid (TsSON) is designed to generate an alternating magnetic flux through a circuit covered by a plasma coil. The center of operation must provide a rise in the plasma current and maintain it at a stationary level for a given time, withstanding the existing mechanical and thermal loads.

To shorten the time interval between tokamak launches, the central autonomous substation must have a conductor cross-section that is optimal for a given value of current and minimum overall dimensions, subject to the required thermal regime.

To increase the manufacturability of manufacturing the solenoid during winding and insulation of the CVSN turns, the length of the conductor should be minimal, which does not require the use of special technological equipment and equipment.

The well-known design of the central repair center (Gusev V.K., Shakhovets K.G., OK-Ridge, October 12-16, 1992 International Symposium), which is a spiral conductor with an internal cooling channel, wound on a technological mandrel in one run in two layers .

However, a single long conductor creates a cooling problem - in order to avoid water overheating, its speed must be increased, which leads to an increase in hydraulic losses and the occurrence of cavitation erosion of the cooling channels.

To compensate for hydraulic losses and maintain flow rate per unit time, it is necessary to increase the capacity of pumping units, the capabilities of which currently allow moving water at a speed of no more than 10 ... 12 m / s, or to develop new methods for cooling conductors.

The closest technical solution, chosen as a prototype, is the Mast installation center (AWMorris and TNTodd for the MAST Team. UKAEA Fusion, Culham Scientre, UKAEA / EURATOM Fusion Association 1997), which is a cylindrical 4-layer structure consisting of 8 spiral conductors with internal cooling channels with two runs in each layer, and the conductors are wound directly on the central column of the product.

In this design, the CSCS conductors connection "current" - serial-parallel, "water" - parallel, while the nodes of the conductors are at the ends.

The main design flaws of the MAST plant are:

- winding the conductor directly onto the central column, which excludes the possibility of monitoring the insulation on the inner surface of the center and on the central column;

- after winding, the design becomes one-piece and repair of inter-turn and inter-layer insulation is difficult;

- a serial-parallel power supply circuit requires a more complex controlled power supply with feedbacks for equalizing currents in parallel circuit branches.

The invention is directed to the creation of the design of the center for the provision of:

- reduction of operational loads due to minimization of currents in switching nodes going across the magnetic field;

- the possibility of dismantling the central heating station from the central column for repair or replacement;

- interchangeability of the central heating station and the central column;

- increasing the discreteness of switching conductors in water, which simplifies the technology for the manufacture of conductors, winding and insulation of coils, as well as reducing hydraulic losses;

- a more uniform magnetic field due to the serial connection of conductors.

The technical result is achieved by the fact that the design of the CVC of the KTM installation consists of four layers of conductors with internal cooling channels, in each of which there are four conductors in the form of a spiral, which are assembled together by screwing after applying insulation and are connected in series.

The invention is illustrated by the drawing, which shows the diagram of the central heating system with the conditionally removed top cover: input terminal 1, output terminal 2, patch block 3, cooling system tube 4, spiral conductor 5, insulation 6, bottom cover 7, cooling channel 8.

The inventive CVSC differs from the prototype in that each layer of conductors is assembled separately from four conductors and all conductors are connected in series.

The inventive CSS is a cylindrical four-layer structure with a total height of 3132 mm with an outer diameter of 562 mm and an inner diameter of 310 mm with four runs in each layer, 16 spiral conductors 5 are wound in layers and have a series connection for uniform distribution of electric current. Each conductor 5 is cooled independently, the switching of the water turns is parallel. TSSON conductors are made of silver bronze (oxygen-free copper with the addition of 0.1% silver) with an electrical conductivity of 101.5% compared to pure copper, the electrical insulation of the TSSON coils and layers is made of polymer composite materials based on polyamide or epoxy binders, ensuring long-term operation at 300-400 ° C or at 150-170 ° C in the second case. The nodes of the connection of conductors are located on the end surfaces of the center for the operation of the center, which reduces the dynamic effect of the magnetic field on the jumpers between the turns of the center.

Slotted grooves are made on the end surfaces of the center for the mechanical perception of power loads on the jumpers from the side of the magnetic field (a soldered connection provides only electrical contact). Switching pads 3 (jumpers) (8 pcs.), Having protrusions for the spline connection and holes for the water cooling system, are soldered to the corresponding surfaces of the CVP conductors. Leading tubes 4 of the cooling system are installed in the holes of the switching blocks 3.

The solenoid operates as follows: current is supplied to terminal 1. Dropping along the descending (the conductors of the first and third layers with the left winding are conventionally called descending) conductors of the first (numbering of the solenoid layers from the center to the periphery) layer and rising along the ascending (conductors of the second and fourth layer with right-hand winding are conventionally called the ascending) conductors of the second layer, the current passes through all eight spiral conductors of the first and second layers, connected in series using blocks 3 located on the upper and lower torus ah solenoid. By block 3, located between terminals 1 and 2, the current passes to the third and fourth layers. Similarly, the current passes through eight spiral conductors of the third and fourth layers, connected in series using blocks 3 located on the upper and lower ends of the solenoid. Then the current goes to terminal 2.

Thus, the current, bypassing all sixteen serially connected spiral conductors, makes 16 × n turns in the direction indicated by the arrow in the drawing (n is the number of turns in each conductor), i.e. the equivalent number of turns of the solenoid is 16 × n.

Since only the ends of the conductors located in close proximity to each other are switched by the blocks, the length of the sections of the blocks 3, where the current flows across the magnetic field, is minimal, therefore, the force acting on the blocks from the side of the magnetic field is also minimal.

Water is supplied to each of the sixteen conductors independently via tubes 4 located at the upper end, and is discharged through similar tubes located at the lower end of the solenoid. Water speed - 1 m / s (up to 5 m / s if necessary).

The inventive ЦСОН represents a whole independently executed unit and provides convenience (manufacturability) of assembly and repair; reduction of operational loads due to minimization of currents in switching nodes extending across the magnetic field, more uniform magnetic field due to only a sequential switching scheme of all four spiral conductors in 4 layers.

Claims (1)

The central solenoid of ohmic plasma heating, containing conductors with internal cooling channels wound in four layers, the connection nodes of which are located on the end surfaces of the switching blocks, characterized in that the conductors are wound with four runs in each layer and connected in series.