JPS58167998A - Radiation shield of nuclear fusion device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Emission@O Technical Field] The present invention relates to a radiation shielding body emitted from a fusion target device, and particularly to a radiation shielding member for transmitting plasma high-frequency heating power to a nuclear fusion reactor. This relates to the shielding body.

C. Technical background of the invention and its problems] In general, in a nuclear fusion device, the transmission path for transmitting high-frequency power for heating plasma passes through the plasma vessel wall consisting of the first wall, the blanket, and the shield. It is necessary to use a round shield that shields radiation such as gamma rays and neutrons that come out from the duct, and a shield that specifically covers the duct and is integrated with the transmission path. By the way, such a shield is made of stainless steel or stainless steel and B4C0.
Since it is made of hybrid materials, it is very heavy, so it is difficult to separate the joined parts when disassembling and reassembling the fused device, and the transmission line may be deformed due to the impact caused by welding when installing and removing it. Become a bird. When the transmission line and the shield are manufactured as an integral structure, the transmission line is extremely susceptible to deformation due to heat.

[Purpose of the invention]

The present invention has been made in view of the above points, and an object thereof is to reduce the weight of a shield for a high frequency transmission line in a nuclear fusion reactor and to facilitate disassembly and assembly.

[1ml' of the invention] The present invention comprises a liquid-tight tank provided surrounding a high-frequency transmission path of a nuclear fusion device and a nine-piece radiation shielding material filled in the solid tank. It is something. Therefore, when disassembling and assembling this nuclear fusion device, if the liquid radiation shielding material in the tank is discharged, the weight will be extremely light and disassembly and assembly will be easy.

[Embodiment of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows the state in which a fusion reactor shield according to the present invention is attached to a fusion reactor, and FIG. 2 shows the basic structure of the fusion reactor shield. This embodiment is an example in which a shield made by Honjitsu 1jiK is applied to the WiO high-frequency coupling part in the grid used for plasma heating by low-a-high pre-resonance, and it can be implemented even when a coaxial feeder line is used.

The cross section of the fusion device basically has a 7' lasma 10 in the center,
Surrounding it *b from the inside - wall 1, plunket 1
2. Consists of a main body shield 13.

The body shield 13 is typically made from stainless steel or a mixture of 84C and stainless steel.

And penetrate the main body shield 13, planter, ) J 2, the first 11, and the high frequency! A round grill antenna 14 for injecting into the plasma 1o is provided near the plasma 1°. A portion where the grill antenna 14 penetrates the furnace wall is covered by a joint shield 15 consisting of a tank 20 filled with a liquid radiation shielding material such as boric acid water or thallium formate. As shown in FIG. 2, the coupling part shielding body 15 consists of a tank 20 and a transmission line 21 that passes through the tank 20 while bending, and includes a shielding material piping J# for injecting, discharging, or circulating liquid radiation shielding material. -bXII is organized. Tank 200 on the side that contacts the main body shield 13
A stepped portion 2 is provided on the surface so that the periphery of the transmission path 21 is one step higher.
2 is provided. The transmission line 21 includes a plurality of waveguides jJm
. . . are bundled together and connected to the grill antenna 14.

Next, the effect will be explained. The joint shielding body 15 configured in this manner shields gamma rays and neutrons leaking from the duct through which the grill antennas 1 and 4 pass through the reactor wall. A liquid radiation shielding material such as boric acid water or thallium formate is supplied into the tank 20 through the shielding material piping 16 to improve its temperature.
is an effective shield against radiation. Further, the shielding material piping 16 not only injects the liquid radiation shielding material into the tank 20 or discharges it from the tank 20, but also performs circulation for cooling the liquid radiation shielding material during operation of the fusion reactor.

By bending the transmission line 21 in the tank 20 to form a nine-fold structure, a reduction in the shielding effect due to the transmission line 21 passing through the tank 20 is suppressed as much as possible. Makyu tank 20
By providing a step on the surface facing the plasma, the radiation leaking from the gap between the joint shield 15 and the main body shield 13 is reduced as much as possible. Furthermore, during disassembly and assembly, the weight of the joint shield 150 can be reduced by draining the liquid radiation shielding material in the tank 20 and emptying the tank 20. Removing the high-frequency coupling section from the furnace body becomes easier when removing it or installing it for assembly.
Work time can also be reduced. Furthermore, by being lightweight, the shock caused by contact with the surroundings during installation and removal of the coupling part is weakened, and it is possible to prevent deformation of the transmission line including the grill antenna.

The tank itself can also be cooled by circulating the liquid shielding medium through a heat exchanger.

Next, a modification of the present invention is shown in FIG. In this embodiment, in order to further enhance the radiation shielding effect, the inner surface of the tank 20 and the surface of the transmission line 21 inside the tank 20 are coated with a material having a large neutron absorption cross section such as B or Cd, or a neutron absorption layer is formed by coniting or the like. 30. tank 2
The neutrons that are scattered within the 0
After colliding with the substance constituting 0 and losing energy, it is absorbed by the neutron absorption layer 30. The presence of such an absorbing layer increases the shielding effect, especially against neutrons, compared to when only a liquid radiation shielding medium is used. The thickness inside the tank 20 can be reduced compared to when only the rolled liquid is used, and the weight can be further reduced.

It goes without saying that the radiation shield described above can be applied to coaxial lines as well.

Figure 2 16 Figure 3

Claims (1)

[Claims] A radiation shield for a nuclear fusion device, comprising: a liquid-tight tank provided surrounding a high-frequency transmission path of the nuclear fusion device; and a liquid radiation shielding material filled in the tank.