JP2915601B2 - Plasma vacuum vessel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

 [Object of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum vessel used for confining plasma in a nuclear fusion device or the like.

[0002]

2. Description of the Related Art A conventional plasma vacuum vessel of a nuclear fusion device will be described with reference to FIGS. FIG. 6 is a schematic sectional view of the plasma vacuum vessel (1). FIG. 7 shows a cross section taken along the line AA of FIG. 6, and has a structure in which the inner wall (2) and the outer wall (3) on the plasma side are connected by a rib (4). Cooling and heating tubes (5) are provided on the inner wall (2) and the outer wall (3), and have a structure in which the plasma vacuum vessel (1) can be baked by flowing a high-temperature gas or the like. The plasma vacuum vessel (1) has a structure also having a function as a shield for neutrons generated by plasma combustion. (It is the superconducting coil and the biological shield that require shielding for neutrons.) Therefore, the configuration of the shielding body varies depending on the shielding level for neutrons. Then, the thickness of the inner wall (2) and the outer wall (3) shown in FIG. 7 becomes a thick plate configuration.

[0003]

When a vacuum vessel having such a configuration is heated for baking, the temperature difference is large because the distance from the heated surface to the outer surface is large, and the thermal stress of the entire vacuum vessel is large. Becomes Further, in order to keep the thermal stress low, it is necessary to increase the temperature raising or lowering time, which lowers the operation rate of the apparatus. If the cooling / heating channel (6) is installed in the inner wall (2) and the outer wall (3) as shown in FIG. 8, this problem is reduced, but there is a disadvantage that the cost is increased.

Further, in the case of a plasma vacuum vessel of a tokamak type fusion device, it is necessary to provide a resistance of one or more turns in the torus direction, and in the case of the plasma vacuum vessel shown in FIGS. A structure in which a high resistance portion is arranged by bellows or the like and a structure in which one turn is completely cut is adopted. In this case, a large eddy current is generated in the plasma vacuum vessel when the plasma is reduced (at the time of disruption), and a large electromagnetic force is generated by interlinking with a toroidal magnetic field or the like. For this reason, the vacuum vessel wall and the connection in the torus direction need to be strong enough to withstand this large electromagnetic force, which results in an increase in size, which increases the size between the plasma and the toroidal coil and increases the toroidal magnetic field. Problems such as an increase in the magnetomotive force of the coil and the poloidal magnetic field coil and an increase in the generated magnetic field occur.

Accordingly, it is an object of the present invention to provide a plasma vacuum vessel having low thermal stress during baking of a vacuum vessel and low electromagnetic force when plasma is extinguished. [Configuration of the Invention]

[0006]

In order to solve the above-mentioned problems, in the present invention, a shielding plate is attached to a rib connecting an inner wall and an outer wall of a thin plate. This shielding plate has a structure connected to only one rib.

[0007]

[Function] When the temperature of the vacuum vessel is increased or decreased, the distance (plate thickness) from the heated surface to the outer surface is small, so that the temperature difference is small and the generated thermal stress can be suppressed low. Is connected and fixed to only one side rib, and has a gap with the opposite side rib, so it can secure one round resistance, prevent the generation of black electromagnetic force, and satisfy the required shielding performance it can.

[0008]

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described. FIG. 1 is a horizontal sectional view (toroidal section) of a plasma vacuum vessel wall, showing a part of the wall.

The inner wall (2) and the outer wall (3) of the vacuum vessel are formed of thin plates, and the two members are welded and integrated by a rib (4). Cooling / heating tubes (5) are attached to the inner surfaces of the inner wall (2) and the outer wall (3), and a shielding plate (7) is attached to one rib (4), and the other end has a gap between the rib and the rib. Hold and install. The ribs (4) are installed at intervals in the toroidal direction. The internal space surrounded by the inner wall (2), the outer wall (3) and the rib (4) is filled with water during operation of the apparatus.

Next, the operation will be described. Since the inner wall (2) and the outer wall (3) are made of thin plates and have a structure having uniform resistance in the torus direction, it is possible to prevent a dark electromagnetic force due to an eddy current generated when plasma is extinguished. Since the outer walls are connected by the ribs (4), it is possible to obtain a plasma vacuum container having improved bending rigidity and high strength.

[0011] The thermal stress caused by the temperature difference caused by the temperature rise and fall during baking of the vacuum vessel also includes:
Since the outer wall is made of a thin plate and the distance from the cooling / heating tube to the back surface is small, thermal stress can be reduced, and the soundness of the vacuum vessel can be improved.

In addition, as a method of attaching a shield plate installed inside, water is filled and connected to only one side of the rib while securing a one-round resistance to the torus because a gap is formed between the rib and the opposite side. In addition, the required shielding performance can be secured. (Embodiment 2) As shown in FIG. 2, a cooling / heating tube (5) is provided outside the outer wall (3). By doing so, the entire assembly of the vacuum vessel can be simplified. (Example 3)

As shown in FIG. 3, the shielding plate (7) is divided and installed so that the total thickness satisfies the required shielding performance.
Each shield plate (7) is attached to the rib (4) alternately in the wall thickness direction. Therefore, the gaps between the mounting surface and the ribs formed on the opposite side are alternately arranged in the wall thickness direction. In this way, neutrons passing through the gap are decelerated and shielded by the next shielding plate (7) in terms of shielding performance, so that shielding performance can be ensured. (Example 4)

As shown in FIG. 4, the inner wall on the plasma side (2)
Are integrated with the inner skin (8), the outer skin (9) and the cooling / heating tube (5), and the outer skin (9)
, A rib (4) continuous in the poloidal direction is connected to the outer wall (3). By doing so, the thermal load from the plasma can be effectively cooled, the thermal stress can be reduced, and a highly rigid vacuum vessel can be obtained. (Example 5)

As shown in FIG. 5, the inner wall (3) on the plasma side
Is connected to an inner skin (8) and a corrugated plate (10) having a corrugated shape in the toroidal direction, and the corrugated plate (1) is integrated.
A structure in which a rib (4) continuous in the poloidal direction is connected to the outside of 0) and further connected to the outer wall (3). This has the same effect as that of the fourth embodiment.

[0016]

As described above, according to the plasma vacuum vessel of the present invention, it is possible to prevent the black electromagnetic force generated when the plasma is extinguished, to reduce the thermal stress generated when the temperature rises and falls, and to reduce the torus. Shielding can be performed reliably while securing one-turn resistance.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a plasma vacuum vessel showing a first embodiment of the present invention.

FIG. 2 is a partial sectional view of a plasma vacuum vessel showing a second embodiment.

FIG. 3 is a diagram of a third embodiment;

FIG. 4 is a diagram of a fourth embodiment;

FIG. 5 is a diagram of a fifth embodiment;

FIG. 6 is a general sketch of a plasma vacuum vessel.

FIG. 7 is a sectional view taken along line A, A in FIG. 6 showing the structure of a conventional plasma vacuum vessel.

FIG. 8 is a sectional view of a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Plasma vacuum container 2 ... Inner wall 3 ... Outer wall 4 ... Rib 5 ... Cooling / heating tube 6 ... Cooling / heating channel 7 ... Shielding plate 8 ... Inner skin 9 ... Outer skin 10 ... Corrugated plate

Claims (4)

(57) [Claims] 1. A torus-shaped plasma vacuum vessel having a rib structure in which an inner wall and an outer wall are connected by a rib arranged at intervals in a toroidal direction, and a shielding plate is provided in a space between the inner wall and the outer wall. A plasma vacuum vessel characterized in that one end of a plate is connected to a rib and the other end is provided with a gap between the rib and an adjacent rib. 2. The plasma vacuum vessel according to claim 1, wherein the number of the shielding plates is two or more, and the connection between the shielding plates and the ribs and the installation of the gap are alternately provided for each shielding plate. 3. The plasma vacuum vessel according to claim 1, wherein a pipe is provided between the inner skin and the outer skin and an integrated inner wall is used. 4. The plasma vacuum vessel according to claim 1, wherein a corrugated plate having a waveform formed in the toroidal direction is connected to the inner skin to form an integral inner wall.