JPS5872094A - Torus type 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 The present invention provides a system that allows humans to access the device for a long time even after the reaction has been carried out for a long time when deuterium and tritium are burned to produce a nuclear fusion reaction. This paper relates to the improvement of a torus-type fusion device.・In a torus-type fusion device, a nuclear fusion reaction is carried out by confining a plasma containing deuterium and 31 hydrogen as components. As a result, 14Me
Since V neutrons are generated, the vacuum chamber for plasma generation and the coils that form the confinement magnetic field become activated.

A device whose purpose is to extract useful energy from a nuclear fusion reaction (because the amount of neutrons generated is enormous, a shield made of concrete or stainless steel is placed between the vacuum vessel and the toroidal coil). In contrast,
In a device that handles all plasma physics experiments with deuterium and tritium as components, the amount of neutrons generated is significantly lower. However, in a state where there are no leprosy bodies, the radioactivity of the device increases as the experiment continues, severely restricting human access to the device. Therefore, it was necessary to effectively block the induced radioactivity in the vacuum vessel against mild neutron generation, suppress the activation of the coils and their supporting structures, and increase the tolerance for human access to the torus device.

The present invention was developed in consideration of the above circumstances, and its purpose is to prevent the induced radioactivity of the vacuum container from being absorbed by a barrier body made of lead, and to also prevent the radiation from being induced in the vacuum container by using polyethylene or paraffin on the outside. By slowing down and absorbing neutrons, preferably by arranging a structure mixed with boron,
Furthermore, it prevents activation of the coils and their support structures located on the outside, and as a result, allows humans to approach the torus device for a long time even after the nuclear fusion reaction with deuterium and tritium has been carried out for a long time. It is a torus-type nuclear fusion device.

The details of the invention will be explained below by means of illustrated embodiments.

In FIG. 1, a plasma 1 containing deuterium and tritium as components generates 14 MeV neutrons as a result of a nuclear fusion reaction. The vacuum vessel 2 for plasma generation is usually made of stainless steel, and some of its components are activated by fusion neutrons and emit gamma rays over a long period of time. This gamma ray is
It is further protected by placing a lead shield 3 on the outside of the vacuum vessel. A neutron moderator 4 made of polyethylene or paraffin is placed outside the gamma ray shield (four bodies). By mixing an appropriate amount of boron into this neutron moderator, the neutrons flowing into the moderator are It is also possible to absorb a certain part of it.

In this way, the neutron energy and neutron flux reaching the toroidal coil 5 and its supporting structure located further outside are reduced, thereby reducing the activation of the coil and supporting structure.

As detailed above, according to the present invention, in addition to blocking gamma rays emitted from the vacuum vessel, deuterium and tritium are allowed to react with each other during activation of coils and support structures located outside the vessel. Humans will be able to approach the device for a long time even after the fusion reaction has been carried out for a long time.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a torus-type nuclear fusion device according to an embodiment of the present invention taken along a plane passing through the torus axis. 2. Vacuum vessel, 3. γ-ray shield,
4... Neutron moderator and absorber, 5... Toroidal coil.

Claims (2)

[Claims] (1) The space between the vacuum vessel for plasma generation and the toroidal coil is surrounded by a shield made of gold-lead, and a neutron moderator made of polyethylene or paraffin is placed outside the shield. A torus-type nuclear fusion device with special features. (2) The torus-type nuclear fusion device according to claim 1, wherein boron is mixed into the neutron moderator so that the neutron moderator also serves as a neutron absorber.