JPS5843204Y2 - Concentric tubular resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resistor suitable for a variable resistance device for adjusting the time constant of change in a current transformer coil current provided in a power supply circuit of a tokamak-type nuclear fusion device, for example.

Recently, research and development of tokamak-type nuclear fusion devices has been carried out, and preparations have begun for implementation from small to large-scale experimental devices.As a result, various performances are required of power supply circuits.

An example of what is currently planned will be explained with reference to FIG. 1, and in particular the performance required of the variable resistance device used therein will be described.

The power supply circuit shown in FIG. 1 includes a current transformer coil DC power source 1, a vertical magnetic field coil DC power source 2, an air-core current transformer coil 4, a vertical magnetic field coil 5, two-stage plasma excitation energy storage coils 6.7, Variable resistance device 8 for constant adjustment, capacitor and resistor 9゜10 for voltage increase rate limit, switch 11゜ necessary for switching on/off polarity, etc. Opposite side switch 12.13
, energy storage coil current backflow prevention device 14, 15
, a variable resistance switch 16 for turning on/off, a diode 17 for preventing backflow of the vertical magnetic field coil current, and a switch 18 for turning on the vertical magnetic field coil power supply.

Note that 3 in the figure is F. It is a lasma circuit.

Thus, electromagnetic coupling with the plasma circuit 3 is obtained from the air-core current transformer coil 4 (which is itself the main inductive energy storage coil) located close to the vacuum vessel.

The functions required of this circuit are the excitation, maintenance, control, and termination of plasma current.

To excite the plasma current, electromagnetic energy is stored in advance by passing a constant DC current through an air-core current transformer coil, and by rapidly cutting off this current, an induced voltage is generated in the plasma.

For this reason, a multi-stage inductive energy storage method is adopted, and it is calculated that the stored energy in each stage reaches several tens of MJ.

In other words, it is necessary to handle such huge electromagnetic energy in the form of pulses.

The variable resistance device 8, which is relevant to the present invention, is necessary for adjusting the time constant of the change in the current transformer coil current and changing the rise time of the plasma current.

At present, it is desired that this resistance value be variable, for example, in about 100 steps in 0.018 increments between about 0.01 and 1.0 Ω.

The desired performance of this variable resistance device is the above-mentioned multi-stage switching capability.

(a) Inductance should be as small as possible for each set resistance value.

For example, several tens of μH or less. (b) The increase in resistance value due to temperature rise of the resistor shall be less than +10%.

Therefore, the temperature rise is limited by the temperature coefficient of the material used for the resistor.

(c) The current is applied in a pulsed manner, for example, for about 2 to 5 seconds, and then there is a rest period of several minutes, for example, about 5 to 10 minutes, and this process is repeated.

Therefore, it is necessary to consider sufficient cooling so that the temperature of the resistor increases due to the above-mentioned pulse current, so that the temperature decreases to the initial temperature during the rest period.

Conventionally, small devices of several tenths of size that have been manufactured in a laboratory use a combination of so-called grid resistors of an air type.

However, if you design a large item using this method, the above (b)
Due to these conditions, the dimensions of each resistor become long, and the overall device combining them becomes extremely large.

For example, it is estimated that the installation area for the design example is approximately 5Qm x 20m.

This is inconvenient as it goes against the requirement (a) of reducing the inductance as much as possible.

In a configuration in which metal tubes are arranged in the same shape as resistors with low inductance and good cooling effect, current flows back and forth between the inner and outer tubes, and the inside of the tube is forcedly cooled with a refrigerant, the current flows back and forth, so the inductance inside the tube is , the outer tube cancels each other out, making it small, and the inside of the tube is forcibly cooled with a refrigerant, so it has a good cooling effect and is suitable as a resistor for this purpose.

The configuration is illustrated in FIGS. 2a and 2b.

In the figure, 20 indicates the entire resistor.

Reference numerals 21 and 22 denote an inner tubular resistor and an outer tubular resistor arranged concentrically, and these surface resistors 21 and 22 have a relatively large specific resistance value and are made of non-magnetic material such as austenitic stainless steel tube. The cross-sectional areas are approximately equal.

23 is a metal end plate that electrically connects one end of the inner tubular resistor 21 and the outer tubular resistor 22 and seals it liquid-tight;
For example, the same stainless steel material as the sheet resistors 21 and 22 is used as the material, and the inner and outer tubular resistors 21 are attached by welding or other means.
．． This is achieved by attaching it to 22.

Reference numeral 24 designates one or more refrigerant communication holes provided near the metal end plate 23 of the inner tubular resistor 21.

Further, 25 is located at the opposite end of the metal end plate 23 in the inner and outer tubular resistors 21 and 22, and makes the outer periphery of the inner tubular resistor 21 and the inner periphery gap of the outer tubular resistor 22 externally. It is a ring made of an insulating material that insulates and seals liquid-tightly and electrically, and its material is, for example, reinforced plastic (FRP).

To attach this insulating ring 25, an adhesive such as epoxy resin is used, for example.

Reference numerals 26 and 27 are electrical terminals provided on the inner and outer tubular resistors 21 and 22, respectively, near the insulating ring 25.

The figure shows a case in which plate-shaped terminals are attached to the outer peripheries of tubular resistors 21 and 22 by a method such as welding.

The method of attaching the electrical terminals 26, 27 is not limited to this, and it goes without saying that a screw type or other terminal configuration may be used.

28 and 29 are refrigerant ports provided on the peripheral surface of the outer tubular resistor 22 near the insulating ring 25.

The open end of the inner tubular resistor 21 can be used as the refrigerant port.

These refrigerant ports 28 and 29 are connected to an insulating hose 30, for example.
It is connected to a supply section and a return section (not shown) of the refrigerant 31 via.

In this case, although the refrigerant 31 is not specified, it may be liquid like oil and have good insulation properties.

Note that the dotted line arrow 32 in the figure indicates the flow of the refrigerant 31, and the solid line arrow 3
3 indicates the flow of current.

Of course, the flow direction may be opposite to that shown in the figure.

With this configuration, the inductance is small.
A resistance element suitable for a variable resistance device of a fusion device power source with good cooling effect was obtained.

By the way, in the above-mentioned resistor, from the condition (b), the cross-sectional area of the metal tube as a resistor has a value determined by the temperature rise, and the resistance value cannot be increased by reducing it below that value. .

That is, the length becomes long. For example, what is currently planned is a load energy of 76 MJ for 5 seconds.
For example, the specific resistance value of a metal tube with a resistance value of 0.3Ω is P = 74μQ
-cm Assuming that the temperature rise is 100℃, the required cross-sectional area is approximately 70m2, and the length of the resistor is approximately 280m2, according to the inventors' calculations.
reach m.

When the above-mentioned concentric tubular resistors are connected in series, for example, the length is 1
0m (round trip length 20m), 14 pieces are required.

In other words, if the number of wires in series is not to be increased too much, each wire needs to have a length of about this length.

Since the configuration is concentric, the electromagnetic mechanical force between the inner and outer tubes should be canceled out and close to 0 when considering the entire circumference, but since it is long as mentioned above, a slight bend in the tube will generate a strong electromagnetic force, and the inner tube will may cause deformation or damage.

Furthermore, when used horizontally, the inner and outer tubes bend under their own weight, so the above-mentioned tendency becomes even more pronounced.

The present invention proposes a configuration in which concentric tubular resistors have high strength against electromagnetic mechanical forces without obstructing the passage of refrigerant and ensuring a gap between the inner and outer resistance tubes.

An embodiment of the present invention is shown in FIG.

Since this is based on the configuration shown in FIG. 2, the same parts are indicated by the same symbols and their explanation will be omitted.

In FIG. 3, 34 is a continuous spiral spacer made of an insulating material.

This is exactly the outer circumference of the inner tubular resistance tube 21 and the outer circumference of the outer tubular resistance tube 2.
Manufactured to fit into the gap on the inner circumference of No. 2.

As for the manufacturing method, for example, FRP is wound around the outer circumference of the inner tubular resistance tube 21, and its thickness is made almost equal to the gap.

This is machined into a continuous spiral shape.

In order to improve the close contact with the inner periphery of the outer tubular resistance tube 22, a highly elastic gasket 35 made of oil-resistant rubber, for example, is pasted on the surface of the spiral as shown in the figure.

In this manner, the inner tubular resistor 21 is inserted into the hole of the outer tubular resistor 22 with the helical spacer 34 and gasket 35 attached to its outer periphery.

The inner tubular resistor 21 and the outer tubular resistor 22 are integrated by a helical spacer 34 and a gasket 35, have high strength against electromagnetic mechanical force, and are not easily bent even when used horizontally.

Furthermore, even if it is slightly bent, there is no problem electrically or mechanically since the inner and outer paper antibodies are bent as a whole.

The refrigerant also flows along the spiral groove.

FIG. 4 shows a modification of the present invention.

That is, one or more short spiral spacers 34 and gaskets 35 may be provided.

The figure shows a case where one is provided almost in the center.

FIG. 5 shows another embodiment of the present invention.

The inner tubular resistor is not necessarily a tube, but may also be a rod 38.

In this case, the refrigerant outlet will be located at the opposite end of the outer tubular resistor 22.

The positions of the electrical terminals 26° and 27 do not change.

According to the present invention, a resistor with high strength against electromagnetic mechanical force, which can be used horizontally, and has a good cooling effect can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing the power supply circuit of a fusion device, Fig. 2 is a conventional concentric tubular resistor, a is a front view with both ends cut away, and b is an X-X line of a. A cross-sectional view along the arrows,
FIG. 3 shows one embodiment of the concentric tubular resistor according to the present invention, and a front view showing a cutaway cross section of both ends, and FIGS. 4 and 5 show other embodiments of the present invention. , is a front view showing a cutaway cross section of both ends. 1... Current transformer coil DC power supply, 2...
Vertical magnetic field coil DC power supply, 3...Plasma circuit, 4...Air core current transformer coil, 5...Vertical magnetic field coil, 6, 7...2 Energy storage coil for plasma excitation in stages, 8... Variable resistance device for time constant adjustment, 9, 10... Capacitor and resistor for voltage increase rate limitation, 11... Switches required for switching off, polarity switching, and turning on, 12.13...Switch for switching off, 14.15...Device for preventing backflow of energy storage coil current, 16...Variable resistor Switch for turning on and cutting off, 17... Vertical magnetic field coil current backflow prevention diode 2.18...
Vertical magnetic field coil power supply switch, 20... shows the entire resistor, 21... inner tubular resistor, 2
2...Outer tubular resistor, 23...Metal end plate, 24...Refrigerant communication hole, 25...
・Insulator ring, 26.27... Electrical terminal,
28.29... Refrigerant port, 30... Insulating hose, 31... Refrigerant, 32...
-.ν Arrow indicating the flow of refrigerant, 33...→Arrow indicating the flow of current, 34... Spiral spacer made of insulator, 35... Gasket.

Claims (3)

[Scope of utility model registration request] (1) An inner tube is inserted concentrically into a metal outer tube, and one end is sealed with a liquid-tight and conductive end plate. Current flows back and forth between the inner and outer tubes, and a refrigerant is allowed to flow inside the tube for cooling. A concentric tubular resistor, characterized in that the concentric tubular resistor is constructed such that an insulating spacer is interposed therebetween, the spacer being engaged with the gap between the inner and outer tubes and having a spiral groove continuous in the axial direction. (2) The concentric tubular resistor according to claim 1, which is a utility model registration, characterized in that an insulating spacer having a spiral groove is interposed intermittently in the axial direction. (3) A concentric tubular resistor according to claim 1, wherein the inner tube is a metal rod.