JP2869495B2 - Nuclear fusion device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a nuclear fusion device, and more particularly, to a tokamak fusion device in which a plurality of diverter plates are arranged in an annular vacuum vessel.

[Conventional technology]

The tokamak-type fusion device includes an annular vacuum container. A toroidal coil is wound around the outer periphery of the container, and an annular poloidal coil is arranged. Then, a configuration is employed in which a magnetic field is formed in the vacuum vessel by each coil, and the charged particles are wound around magnetic lines of force and moved to confine the plasma. In such a device, H ⁺ and H ⁺ undergo nuclear fusion to generate He and extract energy. The hydrogen plasma peripheral layer serving as a fuel for nuclear fusion contains particularly large amounts of impurity particles released from the vacuum vessel. Therefore, in order to remove impurity particles in the plasma peripheral layer, a divertor plate is arranged on the wall surface of the vacuum vessel and a part of the poloidal coil is used as a divertor coil, and the high-energy charged particles in the plasma peripheral layer are diverted along the lines of magnetic force. To neutralize the high-energy charged particles and exhaust the neutralized charged particles from an exhaust port.

However, when the high energy charged particles are constantly colliding with the divertor plate, the divertor plate is greatly worn away, and when the charged particles collide with the divertor plate, the heat that the particles leave on the divertor plate is hit by the magnetic field lines. There is a problem that the diverter plate melts and evaporates locally at the position.

Therefore, a configuration is employed in which the current of the divertor coil is changed to change the position of incidence of the magnetic field lines on the divertor plate, thereby preventing high-energy charged particles from locally concentrating on a specific surface of the divertor plate. . Related devices of this type include, for example, IAE, "Eater Concept Definition", pages 300 to 306 (IAEA, "ITER CONCEPT").
DIFINITION ", pp. 300-306).

[Problems to be solved by the invention]

The above prior art does not consider that changing the magnetic flux by changing the current of the divertor coil causes a large induced eddy current in the toroidal coil or the vacuum vessel. Accordingly, an induced eddy current flows through the toroidal coil and the vacuum vessel, and an interaction between the eddy current and the peripheral magnetic field generates an electromagnetic force, which causes a problem that an excessive force is exerted on the vacuum vessel. In particular, in a fusion device using a superconducting coil as a toroidal coil, there is a possibility that the superconducting coil cannot be kept in a superconducting state due to heat accompanying the AC loss.

An object of the present invention is to provide a fusion device that can prevent localized concentration of charged particles on a diverter plate without changing a magnetic field formed in a vacuum vessel.

[Means for solving the problem]

In order to achieve the above object, the present invention provides, as a first apparatus, sequentially along a circumferential direction of a vacuum vessel, in a region where a magnetic field line is incident toward a vessel wall surface in an annular vacuum vessel containing plasma. The fusion device comprises a plurality of diverter plates arranged and driving means for reciprocating each of the plurality of diverter plates during plasma ignition.

Further, as a second device, in a region where the lines of magnetic force enter the wall surface of the container in the annular vacuum container containing the plasma, they are sequentially arranged at a predetermined angle along the circumferential direction of the vacuum container. The plurality of divertor plates and the diverter plates of the plurality of diverter plates adjacent to each other at a speed that maintains the inside of the annular vacuum container in a vacuum state during plasma ignition are opposite to each other in the radial direction of the annular vacuum container. And a driving means for reciprocating along the axis.

Further, as a third device, in the annular vacuum vessel containing the plasma, the magnetic field lines are sequentially arranged in a region where the lines of magnetic force enter toward the vessel wall while maintaining a predetermined angle along the circumferential direction of the vacuum vessel. A fusion device comprising: a plurality of diverter plates; and driving means for reciprocating each diverter plate of the plurality of diverter plates along a vertical plane at a speed for keeping the inside of the annular vacuum vessel in a vacuum state during plasma ignition. It was done.

[Action]

During the plasma ignition, each diverter plate was moved while keeping the incident position of the magnetic field lines formed in the vacuum vessel constant, that is, without changing the current of the diverter coil. Is maintained in a constant state, and no induced eddy current flows through the coil or the vacuum vessel arranged in the vacuum vessel, and the charged particles can be prevented from locally concentrating on the diverter plate. This can contribute to reducing wear and improving the durability of the device.

As the movement of each diverter plate, each diverter plate is reciprocated in the direction opposite to the adjacent diverter plate along the radial direction in the horizontal plane of the container, or the diverter plate group is divided into a plurality of blocks. By reciprocating the diverter plates of the block along the radial direction in the horizontal plane of the horizontal vessel and in the opposite direction to the diverter plates of adjacent blocks, the center of gravity of the entire device is kept in a constant state and the diverter plate is reciprocated. It becomes possible to exercise. This makes it possible to suppress the vibration of the vacuum vessel caused by the reciprocating motion of the diverter plate.

In addition, when the diverter plate is reciprocated along the vertical plane of the vacuum vessel as the movement of the diverter plate, the moving distance can be reduced as compared with the case where the diverter plate is reciprocated along the horizontal plane of the vessel. .

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

1 and 2, the tokamak fusion device 10
Has a substantially annular vacuum container 12, and a toroidal coil 14 is wound around the outer peripheral surface of the container 12. Further, a substantially annular poloidal coil (diverter coil) 16 is arranged on the outer peripheral side of the container 12. A plurality of exhaust passages 18 are formed on the bottom side surface of the container 12, and a plurality of diverter plates 20 are sequentially arranged inside the container 12 along the circumferential direction. The diverter plate 20 is arranged in a region where the magnetic lines of force 22 bent by the diverter coil 16 are incident toward the wall surface of the vacuum vessel 12, and each diverter plate 20 has a size that can be inserted from the exhaust port 24 of the exhaust passage 20. And is formed in a rectangular shape.

As shown in FIGS. 3 and 4, each diverter plate 20 is supported on a support 26 in an inclined state, and a plurality of rollers are provided on the bottom side of each diverter plate 20 and the bottom side of the support 26. 28 is rotatably fixed. Each roller 28 is movable on a rail 30 attached to the exhaust passage 18. And a support for each diverter plate 20
26 is connected to a driving device 34 via a driving rod 32. The driving device 34 expands and contracts the driving rod 32 to
Is reciprocated along the radial direction of the container 12 in the horizontal plane.

Here, when the diverter plate 20 is inclined, the inclination angle θ of the diverter plate 20 is set in association with the inflow angle θ of the particle bundle moving along the magnetic flux 22. When the ratio between the poloidal magnetic field Bp and the toroidal magnetic field Br is given by the inflow angle θ of the particle flux with respect to the horizontal plane of the container 12, these relations are expressed by the following equation (1).

Next, assuming that the distance between each diverter plate is l, the width of the diverter plate 20 in the toroidal direction is r, and the inclination of the diverter plate 20 from the vessel horizontal plane is the same as the inflow angle of the particle flux, the distance l becomes 2) It is represented by the equation.

l = rvosθ (2) In the above configuration, a vacuum container for storing the plasma 36
12 toroidal coil 14 and diverter coil
When electricity is supplied to the magnetic field 16, a magnetic field line 22 is generated in the container 12. The lines of magnetic force 22 enter each diverter plate 20 with charged particles. At this time, the high-energy impurity charged particles collide with the diverter plate 20 and are neutralized, and the exhaust passage 1
8, is discharged through the exhaust port 24. Since the exhaust port 24 is provided with the bellows 38, the vacuum state in the container 12 can be prevented from being broken when the diverter plate is moved.

Here, in the present embodiment, the diverter plate 20
In order to avoid local concentration of the particle flux, each diverter plate 20 is moved with the incident position of the magnetic flux 22 kept constant with respect to the vacuum container. That is, the current value of the diverter coil 16 is kept constant, and each diverter plate 20 is reciprocated with an amplitude of about 30 cm. When reciprocating each diverter plate 20, the adjacent diverter plates 20
And reciprocate in opposite directions. As a result, even if the diverter plate 20 is reciprocated, the center of gravity of the entire container 12 can be always maintained in a constant state.
It becomes possible to control that 12 vibrates.

If the distance between the diverter plates 20 satisfies the above equation (2), the adjacent diverter plates 20 move in opposite directions to each other, and as shown in FIG. Even when the plate 20 comes out of the line of magnetic force 22, the plasma particle flux that cannot be received by the diverter plate 20 on the left enters the diverter plate 20 on the right. For this reason, the plasma particle flux can be received by any one of the diverter plates 20, and the wear of the container 12 can be prevented. Further, according to the present embodiment, since the diverter plate 20 is disposed at an angle, the magnetic lines of force received by one diverter plate 20 are more intense than when the diverter plate 20 is disposed parallel to the horizontal plane of the container 12. The range of 22 can be expanded, and the number of diverter plates can be reduced.

As described above, according to the present embodiment, since the diverter plate 20 is reciprocated along the radial direction of the container 12 without changing the magnetic flux lines 22, an induced eddy current is generated in the toroidal coil 14 and the container 12. However, it is possible to prevent the particle flux from locally concentrating on the diverter plate 20 and to prevent the diverter plate 20 from being worn, and the AC loss occurs in the droidal coil 14, It is possible to prevent unnecessary electromagnetic force from acting on the container 12.

When moving each diverter plate 20, a plurality of diverter plates 20 are used as one block.
The diverter plate group is divided into a plurality of blocks, and the diverter plate group of each block can be reciprocated in the direction opposite to the diverter plate 20 of the adjacent block along the radial direction in the horizontal plane of the container 12. is there. Furthermore, the diverter plate group is divided into a plurality of blocks with the plurality of diverter plates 20 as one block, the movement timing of each diverter plate 20 is set to a timing shifted sequentially for each block, and the diverter plate of each block is set as described above. It is also possible to reciprocate along the radial direction in the horizontal plane of the container 12 at the specified timing. If such a moving method is employed, the vibration of the container 12 due to the movement of the diverter plate can be suppressed.

Next, when disposing the diverter plate 20 at an angle, as shown in FIG.
The angle θ ₂ between the plasma particle flux incident surface 20A of 20 and the magnetic flux line 22
Is set to an acute angle as shown in the following equation (3), it is possible to easily guide the high energy particle flux incident on the diverter plate 20 to the exhaust port 24 side.

That is, while the inclination angle θ ₂ of the diverter plate 20 is set to an acute angle and the direction of the inclination of the diverter plate 20 is set to the exhaust port 24 side, even if the charged particles that collided with the diverter plate 20 rebound from the diverter plate 20,
It does not return into the plasma 36 but is exhausted from the exhaust port 24. For this reason, the exhaust of the impurity particles can be performed smoothly, and the exhaust efficiency can be improved.

Next, as shown in FIG. 6, a driving device 40 for reciprocating the diverter plate 20 along the vertical direction of the container 12 is disposed on the bottom side of each diverter plate 20, and each driving device 40 drives Even if the diverter plate 20 is reciprocated in the vertical direction, the position where the magnetic field lines 22 are incident on the diverter plate 20 changes, so that the charged particles can be prevented from locally concentrating on the diverter plate 20. In this case, assuming that the incident angle of the particles incident on the diverter plate 20 is θ, the moving distance of the diverter plate 20 in the vertical direction is tan θ of the moving distance in the horizontal direction.
Double. That is, if the horizontal movement distance of the diverter plate 20 is l, the vertical distance is l ', and the incident angle of the charged particles on the diverter plate 20 is θ, tan θ =
l ′ / l, l ′ = ltan θ. Therefore, tanθ
By selecting <1 and moving the diverter plate 20 in the vertical direction, it is possible to make the moving distance shorter than when moving the diverter plate 20 in the horizontal direction.

Further, in each of the above embodiments, a cooling water pipe (not shown) for cooling the diverter plate 20 is provided inside the container 12, but as shown in FIG.
An insertion port 42 is formed on the bottom side and a bellows 44 is disposed around the insertion port 42, a driving device 40 is disposed in the bellows 44 and the exhaust port 42, and a cooling water pipe 46 is provided on the outer peripheral side of the exhaust passage 18. If the cooling water from the cooling water pipe 46 is disposed and supplied to the diverter plate 20 via the driving device 40 and the driving rod 32, there is no need to install a cooling water pipe in the container 12, and the diverter plate Installation of equipment for cooling 20,
Removal can be simplified.

[Effects of the Invention] As described above, according to the present invention, since each diverter plate is moved while maintaining the position of incidence of the lines of magnetic force formed in the vacuum vessel during plasma ignition, the vacuum vessel It is possible to prevent the particle flux from being locally concentrated on the diverter plate without generating eddy currents in the coil and the vacuum vessel disposed in the diverter plate, and to prevent wear of the diverter plate. Since no AC loss occurs in the coil and unnecessary electromagnetic force does not act on the container, it is possible to contribute to improvement of the durability of the device.

Also, when moving the diverter plate, reciprocate each diverter plate in the opposite direction to the adjacent diverter plate, or move the diverter plate in each block in the opposite direction to the diverter plate in the adjacent block. Reciprocating,
Further, if the reciprocating motion is performed by sequentially shifting the movement timing of the diverter plate of each block, it is possible to suppress the container from vibrating due to the reciprocating motion of the diverter plate.

[Brief description of the drawings]

FIG. 1 is a toroidal sectional view showing an embodiment of the present invention,
FIG. 2 is a cross-sectional view of the container, FIG. 3 is a diagram for explaining the configuration of the diverter plate, FIG. 4 is a diagram for explaining the relationship between the magnetic field lines and the diverter plate, and FIG. FIG. 6 is a view for explaining the relationship between a diverter plate and lines of magnetic force showing the embodiment of FIG. 6, FIG. 6 is a sectional view of a poloidal showing another embodiment of the present invention, and FIG. It is sectional drawing. 10 ... tokamak fusion device, 12 ... vacuum vessel, 14 ... toroidal coil, 16 ... diverter coil, 18 ... exhaust passage, 20
... Diverter plate, 22 ... Magnetic field lines bent by the diverter coil, 48 ... Magnetic field lines that confine the plasma,
24 ... Exhaust port, 26 ... Support, 28 ... Roller, 30 ... Rail, 32
... drive rod, 34 ... drive device, 36 ... plasma, 38 ... bellows, 40 ... drive device, 42 ... insertion opening, 44 ... bellows, 46 ... cooling water piping.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Okazaki 1168 Moriyamacho, Hitachi City, Ibaraki Prefecture Inside Energy Laboratory, Hitachi, Ltd. In-house (72) Inventor Kazuhiro Takeuchi 1168 Moriyama-cho, Hitachi City, Ibaraki Pref. Energy Research Laboratory, Hitachi, Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) G21B 1/00

Claims (3)

(57) [Claims] 1. A plurality of diverter plates sequentially arranged along a circumferential direction of a vacuum vessel in a region of a ring-shaped vacuum vessel containing plasma in which a magnetic field line is incident toward a wall of the vessel. A driving means for reciprocating each of the plurality of diverter plates. 2. A method according to claim 1, wherein a plurality of magnetic vacuum lines are sequentially arranged at a predetermined angle along a circumferential direction of the vacuum vessel in a region of the annular vacuum vessel for accommodating the plasma, in which a line of magnetic force enters the wall of the vessel. A diverter plate and each diverter plate of the plurality of diverter plates adjacent to each other at a speed that maintains the inside of the annular vacuum container in a vacuum state during plasma ignition are arranged in opposite directions along the radial direction of the annular vacuum container. A fusion device having reciprocating drive means. 3. A plurality of annularly arranged vacuum chambers, each containing a plasma, and sequentially arranged at a predetermined angle along a circumferential direction of the vacuum vessel in a region where a magnetic field line enters the wall of the vessel. A fusion apparatus comprising: a diverter plate; and driving means for reciprocating each diverter plate of the plurality of diverter plates along a vertical plane at a speed that maintains a vacuum state in the annular vacuum vessel during plasma ignition.