JP3354909B2 - Method for supporting vacuum vessel of fusion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear fusion device for performing a nuclear fusion reaction or a test thereof, and more particularly to a method for supporting a vacuum vessel.

[0002]

2. Description of the Related Art Various types of test devices for performing a nuclear fusion reaction have been proposed and are being developed. A typical example thereof is a so-called tokamak type fusion device. A typical structure is conceptually shown in FIGS. Explaining the main components, the hollow donut-shaped vacuum vessel 1 that defines an ultra-vacuum space for generating and confining a high-temperature plasma P is as follows.
A toroidal coil 5 and a poloidal coil 7 which are installed via the support structure 3 and form a magnetic field for confining the plasma P are disposed therearound. These toroidal coil 5 and poloidal coil 7 are heavy structures themselves, and are securely supported on the floor via support structures 9 and 11, respectively. Further, as described above, an exhaust device for maintaining the inside of the vacuum vessel 1 at an ultra-vacuum, a supply device for a reaction raw material, a device for further heating the plasma, various measurement and measurement devices, etc. are provided around the vacuum container 1. In order to communicate these various devices with the inside of the vacuum vessel 1, the vacuum vessel 1
Are provided with ports 13 and 15. Note that the horizontal arrangement of the device actually differs depending on the shape of the port, but is basically rotationally symmetric, so that FIG. 11 shows only one quadrant of the horizontal cross section, and reference numeral 17 shows a living body shield.

[0003] The vacuum vessel 1 as described above is a large structure by itself and therefore has a corresponding weight, and further exhibits a large thermal expansion due to heat input during baking or operation. Therefore,
The support structure 3 of the vacuum vessel 1 is required to have a function of supporting a vertical load while restraining generation of excessive thermal stress without restricting thermal expansion. In order to satisfy such functional requirements, a support structure of a lower support method as shown in FIGS. 12A and 12B is employed. For example, the one shown in FIG. 12 (a) has support legs 3a which are pin-supported at the top and bottom,
The main thermal expansion indicated by the arrow is released by pivoting of the pin portion, and the vertical load is received by the shearing support of the pin portion. In the structure shown in FIG. 12B, a support leg 3b having a small bending rigidity in the main thermal expansion direction is used, and the thermal expansion is released or absorbed by bending displacement.

[0004] A supporting structure of a side support system as shown in FIG. 13 has also been proposed. In this case, a support block 1a is integrally formed on the side body of the vacuum vessel 1 provided with the port 13 and the like as described above (FIG. 7A), and a support seat 19 is slidably fitted thereto. The vertical load is supported by the upper and lower sliding surfaces. The support block 1a extends in the main thermal expansion direction, and displacement caused by thermal expansion is released or absorbed by sliding,
Do not restrain.

[0005]

However, the above-mentioned conventional support structure has the following problems. That is, when a disruption or an earthquake occurs, a large horizontal load acts on the support structure in addition to the vertical load due to the weight of the vacuum vessel 1 and the like. In such a case, the lower support type as shown in FIG. 12 is characterized in that the rigidity of the main body of the vacuum vessel 1 is generally relatively high and the rigidity of the support structure is low, so that the natural frequency is low and the rigidity is low. Has vibration characteristics.
To improve this, it is necessary to increase the rigidity of the support legs of the support structure, but there is a limit due to restrictions on the size of the occupied space due to peripheral devices in the overall arrangement,
The desired vibration characteristics have not yet been achieved. In the side support type shown in FIG. 13, the vertical load and the horizontal load must be simultaneously supported by the fitting structure of the support block and the support seat. Has to be missed, so that there is a problem that the entire structure becomes complicated. Furthermore, as described above, the spatial restrictions imposed by the relationship with peripheral devices are greater than the former, and the size of the support structure, that is, the increase in the rigidity of the support portion, has not been satisfactory. Therefore, a similar problem on vibration characteristics remains.

When the natural frequency of the device is small, the following problem occurs. That is, the displacement between the vacuum vessel and peripheral devices such as the toroidal coil becomes large, and it is necessary to secure a large space for avoiding mutual interference between these devices. Further, in the case where a radioactive product such as tritium is expected to be generated by a nuclear fusion reaction, there is a possibility that a rigid structure design may be required due to the regulation of the authority in consideration of safety and the like.
As shown in FIG. 14, an oil damper 2 having a piston / cylinder structure is provided between the vacuum vessel 1 and the surrounding pedestal 21 in order to suppress deformation in a rapid vibration mode such as disruption.
It has also been proposed to provide three. However, in this method, although the vibration characteristics are improved, there is a problem of neutron irradiation. That is, the access of the worker is restricted, and the maintenance and inspection of the oil damper 23 is restricted.
There is a risk of loss of function due to deterioration of oil properties due to neutron irradiation, and it is still difficult to solve specific problems. Therefore, the present invention provides a method of supporting a so-called maintenance-free fusion device which adopts a rigid support method corresponding to a rigid structure design as a vibration characteristic of the device main body and does not require special maintenance and inspection. Make it an issue.

[0007]

According to the present invention, there is provided a nuclear fusion device having a structure such as a hollow donut-shaped vacuum vessel, a toroidal coil, and a poloidal coil. The vertical load is supported by a thermal expansion-absorbing support structure installed below the vacuum vessel, and a support beam opposed to the vacuum vessel with a thermal expansion displacement gap between the vacuum vessel and a supported surface on the side of the vacuum vessel. Support horizontal load. The other end of the support beam is supported directly or via an overhang on a mount on which the vacuum vessel is installed or a living body shield provided integrally therewith. These support beams and overhangs are given rigidity so as to obtain predetermined vibration characteristics. The gap between the supported surface of the vacuum vessel and the support beam is maintained at a suitable amount by interposing an adjusting member whose thickness can be easily set so as not to restrict thermal expansion.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First, referring to FIG. 1, the vacuum vessel 31 of the fusion device 30 is mounted on a floor 35 via a support structure 33. To facilitate understanding of the present invention, peripheral devices such as a toroidal coil installed around the vacuum vessel 31 are not shown, but necessary devices are installed at required positions as in the conventional device. I want to be understood. The vacuum container 31 is surrounded by a living body shield 37 erected on the floor 35. The support structure 33 has the structure described in the section of the related art, and can release the thermal expansion displacement in the horizontal direction without restraining it and can support the load in the vertical direction. Therefore, it has a support leg with both ends pin-coupled or one with a relatively small bending rigidity in the main thermal expansion direction. A support portion 39 is formed on the side surface of the body of the vacuum vessel 31, and the tip of the support beam 41 extending from the wall of the living body shield 37 faces the support portion 39.

FIG. 2 shows the relationship between the support beam 41 and the support 39 in an enlarged manner. Support beam 41 and support 3
9 is set to be substantially zero during normal operation, even if a horizontal load due to an earthquake or the like acts during operation, the adjustment member 43 such as a shim can support the support beam 4.
1 and is adjusted so that the gap becomes an appropriate value at the time of installation or at the time of suspension of operation. FIG. 3 shows a state where the support portion 39 is attached to the vacuum vessel 31. If the required rigidity or strength cannot be obtained, a support frame 45 having a relatively large area may be provided as shown in FIG. Also, as shown in FIG. 5, when the living body shield 47 is relatively large and the length of the support beam to be installed becomes large, and the rigidity of the horizontal support is reduced and the relationship with peripheral devices occurs, the configuration shown in FIG. As described above, when the projecting portion 53 is protruded from the attachment portion of the living body shield 47 and the supporting beam 51 is supported on the projecting portion 53, the vacuum vessel 31 can be suitably supported without lowering the vibration characteristics.

A description will be given of the vibration characteristics obtained by the support structure having the above configuration. For comparison, first, the vibration characteristics of the conventional support method will be outlined. FIG. 6 is a schematic diagram showing the above-described support structure of FIG. 12 as a vibration system.
The support structure 3 is represented as a beam 61 and the vacuum vessel 1 is a rigid body 6
It can be expressed as 3. As can be easily understood from this simulated vibration system, the vibration characteristics are determined by the rigidity of the beam 61, that is, the support structure 3. Further, the support structure of the conventional side support method (FIG. 13) can be simulated as a vibration system as shown in FIG. FIG. 7A is a diagram of the simulation system viewed from the side, and FIG. 7B is a diagram of the simulation system viewed from above. As can be seen from FIGS. 7A and 7B, a member 65 representing a support block projects from a rigid body 63 representing a vacuum vessel 1 and a member 6 corresponding to a support seat.
7 supports a horizontal load and a vertical load. Therefore, the vibration characteristics of the device main body are determined by the rigidity of the support block and the support seat. If the support portion is small, sufficient rigidity cannot be obtained. Furthermore, the support structure using an oil damper (FIG. 14) can be simulated to the system shown in FIG. In this system, horizontal and vertical loads are supported by the members 61 and 69, that is, the support structure 3 and the damper 23, and become rigidly supported. However, when the function of the damper 23 is lost, the same as FIG. It becomes a system like this, and there is a similar problem.

In contrast to such a conventional type, the support structure of the present embodiment shown in FIGS. 1 to 5 is simulated as a vibration system as shown in FIG. That is, the vacuum vessel 31 is simulated by a rigid body 63, the support structure 33 supported by the floor 35 is simulated by a beam 61, and the support beam 41 is simulated by a column 71. Therefore, as easily understood from this simulation system,
Improvements in the vibration characteristics of the rigid support structure are achieved, which are not affected by neutron irradiation, and good characteristics can be obtained over the entire lifetime. In the above-described embodiment, the support beam is supported by the living body shield. However, it is needless to say that the support beam may be mounted on another stand and supported.
Similar effects can be obtained.

[0012]

As described above, according to the present invention,
Since the supporting structure and the supporting beam, which are merely mechanical structural members, are used as the supporting member of the vacuum vessel, the vibration characteristics of the rigid supporting structure can be improved. Furthermore, these support structures have a long-term good support effect without any deterioration in their function even when irradiated with neutrons, and without requiring any maintenance work or maintenance. Further, since the support beam supports the horizontal load, the horizontal load conventionally applied by the lower support structure is reduced, so that the cost can be reduced by reducing the strength and the manufacturing cost can be reduced by simplifying the structure.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a main part of a nuclear fusion device according to an embodiment of the present invention.

FIG. 2 is a partial side view showing a main part of FIG.

FIG. 3 is a partial perspective view showing a part of FIG. 2 in an enlarged manner.

FIG. 4 is a partial perspective view showing a partially modified example of the structure shown in FIG. 3;

FIG. 5 is a conceptual diagram of a main part of a modified embodiment in which a part of the embodiment is modified.

FIG. 6 is an explanatory diagram showing a vibration system simulating one of the conventional techniques.

FIG. 7 is an explanatory diagram showing a vibration system simulating another conventional technique.

FIG. 8 is an explanatory view showing a vibration system simulating still another conventional technique.

FIG. 9 is an explanatory diagram showing a simulated vibration system for explaining the operation of the present invention.

FIG. 10 is an elevational sectional view showing an arrangement of a main part of a conventional fusion device.

FIG. 11 is a partial plan sectional view taken along line XI-XI in FIG. 10;

12 is a partially enlarged elevation view showing a part of FIG. 10 in an enlarged manner.

FIG. 13 is a partial perspective view showing a main part of another related art.

FIG. 14 is a conceptual diagram showing a main part of still another conventional technique.

[Description of Signs] 30 Fusion device 31 Vacuum container 33 Support structure 35 Floor 37 Biological shielding 39 Support portion 41 Support beam 43 Adjusting member 51 Support beam 53 Overhang portion

Claims (5)

(57) [Claims] 1. A fusion device having a structure such as a hollow donut-shaped vacuum vessel, a toroidal coil, and a poloidal coil, wherein a load acting on the vacuum vessel is supported in a horizontal direction and a vertical direction, respectively, and the horizontal load is reduced by the vacuum. A side portion of the vacuum container, which is provided between the container and the living body shield or the gantry.
With a thermal expansion displacement gap between it and the supported surface
A method for supporting a vacuum vessel of a fusion device, wherein the method is supported by a support beam as a support column . 2. The method for supporting a vacuum vessel of a nuclear fusion device according to claim 1, wherein an overhang portion is provided on the living body shield or the gantry, and the support beam extends from the overhang portion. 3. A shape is formed on the supported surface on the side of the vacuum vessel.
The method for supporting a vacuum vessel of a nuclear fusion device according to claim 1, wherein a support plate or a support frame is provided on the formed support portion. 4. An adjusting member is interposed in a gap between the support portion and the support beam of the vacuum container, and the adjusting member is configured not to restrain thermal expansion of the vacuum container. The method for supporting a vacuum vessel of a nuclear fusion device according to claim 1, wherein: 5. The nuclear fusion device according to claim 1, wherein the vertical load of the vacuum vessel is supported by support legs provided below the vacuum vessel, and thermal expansion of the vacuum vessel is not restrained. The method of supporting the vacuum vessel of the device.