JPS6239954B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum vessel for a nuclear fusion device, and in particular,
The present invention relates to a vacuum vessel for a nuclear fusion device that is formed into a substantially toroidal shape by alternately connecting thick rings and bellows by welding.

Generally, an annular vacuum vessel is used in a nuclear fusion device, such as a torus-shaped nuclear fusion device. An outline of the torus-shaped fusion device is shown in FIGS. 1 and 2. As shown in the figure, the nuclear fusion device includes a toroidal vacuum vessel 2 that encloses a plasma 1, a toroidal magnetic field coil 3 that generates a magnetic field for plasma confinement, a poloidal magnetic field coil 4, a pedestal 5 that supports these, and a current transformer. 6. It consists of a vacuum evacuation device 7 connected to a vacuum container, and the vacuum container 2 includes:
Thick rings 8 and bellows 9 are alternately arranged and welded together to form a substantially toroidal structure.

Usually, the bellows 9 is made of a thin plate material in order to increase the electrical resistance (one-turn resistance) of the vacuum container 2, which is a condition for generating plasma 1, and to absorb the expansion and contraction of the vacuum container 2 due to plasma heat. ing. On the other hand, the thick ring 8 requires rigidity so as to obtain vacuum force, and is therefore made of a thick plate material. As shown in FIG. 3, the thick ring 8 and the bellows 9 are joined by welding, which is most excellent in vacuum (airtightness). Normally, thick ring 8
When welding together materials with significantly different thicknesses, such as the bellows 9 and the bellows 9, in order to avoid concentration of stress due to external forces such as vacuum force, the part of the thick ring 8 to be welded is cut and formed using a machine, etc., and the plate of the bellows 9 is Generally, the thickness is approximated, the two ends are abutted, and a weld 11 is applied to the abutting tip, and this method has conventionally been followed.

However, the rolling direction 10 of the cut-formed thick ring is the direction shown in FIG. 3 from the top of the annular vacuum container. Generally, rolled steel materials are not completely free of pinholes and impurities in the steel ingot, and are often scattered in the rolling direction in the form of laminations. Therefore, vacuum leakage in the thickness direction is difficult, but leakage occurs easily in the direction parallel to rolling. Therefore, the vacuum in the direction parallel to the rolling direction is the vacuum of the fusion device (1×
At high vacuums (below 10 ^-7 Toll), the amount of leakage increases, and the reliability of the vacuum container is poor.

The present invention has been made in view of the above-mentioned points, and its object is that even if thick-walled rings and bellows are alternately welded and joined,
It is an object of the present invention to provide a highly reliable vacuum vessel for a nuclear fusion device in which the rolling direction of parts to be welded and joined is eliminated and there is no vacuum leakage between structures in the rolling direction.

The present invention performs build-up welding on the outer circumference of the thick-walled ring near the part that contacts the tip of the bellows, and alternately welds and connects the thick-walled ring at the welded portion to the tip of the bellows to form a vacuum vessel. By forming it, the intended purpose is achieved.

The present invention will be described below based on embodiments shown in the drawings. Incidentally, the same reference numerals are used for the same parts as in the past.

FIG. 4 shows an embodiment of the present invention. As shown in the figure, in this embodiment, the thick rings 8 which are arranged alternately with the bellows 9 and welded thereto are overlaid by welding 12 at the portions that contact the tip ends of the bellows 9 (areas where stress is concentrated due to external force). This overlay weld 12 portion and the tip end of the bellows 9 are welded and connected at a weld portion 11. By doing so, the rolling direction 10 can be eliminated in the welded part of the thick ring 8, so there is no vacuum leak from between the welded parts of the thick ring 8 in the rolling direction, and the vacuum resistance is reliable. Improves sex.

According to the vacuum vessel for the nuclear fusion device of the present invention as described above, there is no vacuum leak from the welded joint between the thick ring and the bellows, and a high vacuum can be obtained, so this type of vacuum vessel is highly reliable. It will be done.

[Brief explanation of the drawing]

Figure 1 is a partially sectional plan view of a torus-shaped fusion device, Figure 2 is a vertical cross-sectional view taken along the line A-A in Figure 1, and Figure 3 is a conventional welding of a thick-walled ring and bellows. FIG. 4 is a sectional view of a welded portion showing an embodiment of the present invention. 1... Plasma, 2... Vacuum container, 3... Toroidal magnetic field coil, 4... Poloidal magnetic field coil, 5... Mount, 6... Current transformer, 7... Vacuum pumping device, 8... Thick wall ring , 9... bellows, 10
...Rolling direction, 11... Welded part, 12... Overlay welded part.

Claims (1)

[Claims] 1 Thick-walled rings and bellows are arranged alternately, and both are connected by welding to form a substantially toroidal shape, and in contact with the tip of the bellows in a vacuum vessel of a nuclear fusion device that stores plasma inside. A vacuum vessel for a nuclear fusion device, characterized in that it is formed by performing overlay welding on the outer circumference of the thick-walled ring near the part, and by welding and connecting the thick-walled ring at the welded part to the tip of a bellows. .