JPH06308265A - Nuclear fusion device and its operating method - Google Patents

Abstract

PURPOSE:To dispense with or simplify a facility for suppressing instability, take a preventive measure for an intra-reactor structure, and improve safety by intentionally inducing the instability of plasma. CONSTITUTION:A plasma measurement diagnostic device 1 obtains the distribution of plasma 3 from the measurement signal of a sensor 2 and outputs it to an arithmetic unit 4. The arithmetic unit 4 judges the instability of the plasma 3 from the data and outputs the control signal to a control device 5. The control device 5 sends an operational instruction to a heating device 6 and interlockingly sends an instruction for the flow adjustment of the cooling water of an intra-reactor structure 8 to a pump 7. The heating device 6 controls the heating of the plasma 3 based on the instruction. An instruction for controlling instability can be sent to the control device 5 from a control console 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fusion device for controlling instability of plasma in a fusion device and a method of operating the same.

[0002]

2. Description of the Related Art In a conventional fusion device, it is necessary to suppress the instability of plasma in order to obtain a stable fusion output, and the following method is considered for that purpose.

(1) As described in Japanese Patent Application Laid-Open No. 62-284288, the plasma is generated by rotating the magnetic surface by changing the current flowing to a helical coil that creates a magnetic field in the poloidal plane around the plasma. It was supposed to prevent the growth of instability by changing the magnetic surface shape of.

(2) As described in Japanese Patent Application Laid-Open No. 60-97291, the instability is suppressed by high-frequency driving, such as forcibly driving the plasma current at a high frequency on a growing magnetic island of instability. It was like this.

(3) As described in JP-A-62-38387, when pellets are driven into plasma, the pellets are melted and the plasma is cooled. At the same time, fuel is injected into the plasma and the density is increased. Utilizing this, the distribution of plasma was adjusted to suppress instability.

[0006]

In the conventional control method described above, the control for stabilizing the instability is difficult and complicated. For example, when the instability is stabilized by a magnetic field, a helical coil that is not used for normal operation is newly required. Also, in order to stabilize the instability by high frequency heating, it is necessary to match the frequency to the magnetic island region, but two types are required, including the one for plasma ignition used in the central region (frequency variable). One type is enough if there is a high frequency heating device, but it has not been developed yet). Further, in the case of stabilizing the instability by pellet injection, it is difficult to finely adjust the amount of fuel and the injection direction due to pellet injection. From the above points, when trying to stabilize the instability, the control device becomes complicated and there is a problem in reliability and safety.

An object of the present invention is to provide a fusion device and a method of operating the same which can simplify the device and improve safety.

[0008]

In order to achieve the above object, the present invention uses a measuring device for measuring a physical quantity such as a pressure distribution, a density distribution, or a temperature distribution of plasma to obtain a distribution that causes instability of plasma. It is judged by the calculator whether it is present or not, and the control device issues a command to the heating device that gives energy from outside the plasma to induce the instability of the plasma and saturate it. It is designed to control instability by using the mechanism of tenancy.

[0009] Preferably, in conjunction with the operation of the heating device, the flow rate of the cooling medium to the furnace internal structure is controlled to increase, damage to the plasma facing surface can be reduced, and safety can be improved. It was done like this.

[0010]

[Operation] Magnetohydrodynamic instability of plasma includes sausage instability, kink instability, exchange type instability, tearing mode instability, and the like. When these instabilities develop and become saturated, the plasma pressure distribution, density distribution, or temperature distribution has a flat or gentle gradient distribution shape inside the magnetic surface (rational surface) where the rotational transformation becomes a rational number. Is known to keep. This property is called profile consistency and has been found to be independent of the heating device that induces instability. For example, experimentally, the Comments Plasmas Physics Contracted Fusion 11 (87 ') 63 (Comments Pl
Asma Phys. Contr. Fusion 11 (1987) 63),
It has been reported that the profile consistency is independent of the heating device. In addition, Plasma Physics Contracted Fusion 32
(90 ') 327 (Plasma Phys. Contr. Fusion 32 (199
(0) 327), a numerical simulation study has reported that magnetohydrodynamic instability drives the mechanism of profile consistency.

Therefore, in the present invention, the plasma distribution and the like are measured by the measuring device, and the arithmetic unit determines whether or not the plasma has a distribution that causes instability.
In response to this, the control device issues a command from the outside of the plasma to the heating device to induce the instability of the plasma and saturate it, thereby controlling the instability. As a result, it is possible to maintain the pressure distribution, the density distribution, or the temperature distribution of the plasma in a constant shape by positively inducing the instability by utilizing the profile consistency mechanism. Therefore, a device such as a helical coil or a high-frequency heating device pellet injection device for suppressing instability and a control mechanism can be unnecessary or simplified, so that the configuration of the fusion device can be simplified and reliability can be improved. it can.

[0012] Preferably, instability induces an increase in heat flux, so that the safety can be improved by increasing the flow rate of the cooling medium to the internal structures in advance.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a basic configuration of a nuclear fusion device according to an embodiment of the present invention. Plasma measurement diagnostic device 1
Is the pressure distribution P of the plasma 3 from the measurement signal of the sensor 2.
(r), density distribution n (r), temperature distribution T (r), etc. (where r indicates the position from the center of the torus cross section) are obtained and output to the calculator 4. The computing unit 4 determines the instability of the plasma from the data of the plasma distribution and the like, and when the instability control of the plasma is shown and it is determined that the instability control is necessary, the control device 5 is operated according to the state of the plasma. Output a control signal to. The control device 5 outputs a command regarding the operation of the heating device 6 that induces instability based on the control signal. Further, the control device 5 outputs a command to the pump 7 for adjusting the flow rate of the cooling water for removing the heat of the in-core structure 8 in conjunction with outputting the command to the heating device 6. The heating device 6 controls heating of the plasma 3 based on the command. Further, the operator can output an instability control command from the control console 9 to the control device 5 in order to adjust the fusion output.

The following method is used for plasma measurement diagnosis. The radiation intensity measurement of soft X-ray is used to obtain the pressure distribution, and the electron temperature and the electron density are obtained by passing the laser light through the plasma to determine the wavelength spread and the scattering intensity of the scattered light of Thomson laser scattering, respectively. To use.

As the heating device, a particle injection device and a high frequency heating device are used. Particle injectors include NBI (neutral particle injector) and negative ion injectors, and high frequency heating devices include ECH (electron cyclotron frequency band heating) and IC.
There are H (ion cyclotron frequency band heating) and LHH (lower hybrid wave frequency band heating).

According to the present embodiment, the equipment for stabilizing the instability is not required, so that the structure of the fusion device can be simplified. When the instability grows and saturates,
Some of the plasma's energy goes out, so if you don't know when the instability grows and saturates, you should always keep the cooling capacity of the reactor internals to withstand it. I won't. However, if the instability of the plasma is artificially induced as in this embodiment, the output of the pump may be increased at that time, so that the safety of the reactor internal structure can be improved. Also, by lowering the normal output of the pump and temporarily increasing the output of the pump only when instability is induced, it is possible to ensure sufficient safety for the internal structures of the reactor. Can be reduced.

[0017]

According to the present invention, equipment for suppressing instability can be eliminated. In addition, since the instability of plasma is artificially induced, it is possible to take preventive measures against the internal structure of the furnace and enhance the safety.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a nuclear fusion device according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Plasma measuring / diagnosing device, 2 ... Sensor, 3 ... Plasma, 4 ... Computing device, 5 ... Control device, 6 ... Heating device, 7 ... Pump, 8 ... Reactor internals, 9 ... Control console.

Claims (5)

[Claims] 1. A method of operating while controlling the plasma of the core of a fusion reactor, utilizing a profile consistency mechanism for maintaining a constant distribution profile of the plasma by inducing instability in the plasma. A method for operating a fusion device, comprising controlling the pressure distribution, density distribution, or temperature distribution of the plasma. 2. The method of operating a nuclear fusion device according to claim 1, wherein a particle injection device or a high frequency heating device is used as a heating source for inducing instability in the plasma. 3. A fusion device, comprising: a measurement / diagnosis device for measuring a physical quantity of plasma; and a heating device for inducing instability in the plasma based on a signal from the measurement / diagnosis device. . 4. The method of operating a nuclear fusion device according to claim 1, wherein the flow rate of the cooling medium to the internal structure is controlled in conjunction with inducing instability. 5. The fusion device according to claim 3, further comprising a controller for controlling the flow rate of the cooling medium to the internal structure of the reactor in association with the operation of the heating device.