JPS6110785A - Nuclear fusion blanket - 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] (a) Purpose of the invention [Field of industrial application] This invention relates to a blanket for a nuclear fusion reactor using lithium ceramic spheres such as lithium oxide or lithium aluminate as a tritium breeder material. be.

[Prior Art] Lithium oxide or lithium ceramics such as lithium aluminate are considered to be the most popular fusion blanket materials. In addition, it is preferable to use the material in the form of spheres, and the experimental reactor being planned in Japan is designed to have spheres filled in a metal container.

By the way, when using a blanket structure filled with lithium ceramic spheres, the effective thermal conductivity of the ceramic sphere layer must be good for removing the heat generated in the blanket material (during furnace operation), but the The thermal contact resistance is large, making it difficult to remove sufficient heat.

In particular, the current design is aiming for a dense f! 1:80%T,D
The surface of the sintered body in the vicinity has a problem of severe microscopic unevenness and high thermal contact resistance.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned circumstances, and in a nuclear fusion blanket of the type in which lithium ceramic spheres are filled in a metal container, the lithium ceramic spheres are separated from each other, and It is an object of the present invention to provide a fusion blanket in which heat generated in the blanket material during reactor operation can be easily cooled and removed by increasing the effective thermal conductivity between the lithium ceramic spheres and the metal container.

(b) Means for solving problems in the structure of the invention] Corresponding to this purpose, the nuclear fusion blanket of the present invention coats lithium ceramic spheres with nickel metal, and then coats copper thereon. The metal-coated lithium ceramic sphere and the copper sphere having a smaller diameter than the lithium ceramic sphere described in 11+l are mixed and filled in a metal container.

[Function] In the normal design, a blanket is installed around the fusion plasma reactor core, but it is effective in transferring the heat generated in the core to the outside and removing the heat generated by the blanket's own neutrons. must be carried out. The nuclear fusion blanket of the present invention, which is a mixture of metal-coated lithium ceramic spheres and copper spheres and filled in a metal container, has a ceramic sphere surface that has good thermal conductivity compared to conventional fusion blankets that are simply filled with lithium ceramic spheres. Furthermore, the voids formed between the metal-coated lithium ceramic spheres are filled with copper spheres smaller in diameter than the metal-coated lithium ceramic spheres. The number of contact points between the balls and between the metal-coated lithium ceramic balls and the metal container is increased, and the heat transfer characteristics are significantly (100 times or more) better.

[Example] The figure is a partial sectional view of a nuclear fusion blanket according to the present invention. In the figure, numeral 1 indicates a lithium ceramic sphere (diameter 2 to 10 mm) such as lithium oxide or lithium aluminate.
Tritium is generated by irradiation of neutrons from the core of a nuclear fusion reactor. The entire surface of the lithium ceramic sphere 1 is coated with nickel metal 2, and further, copper 3 is thinly coated on the nickel metal 2.

The coating of nickel metal 2 and copper 3 on the lithium ceramic sphere 1 is done by known technical means (e.g. vacuum evaporation method).
A value of 0 micron or less is preferable.

When evaporating nickel gold 113, the surface direction of the evaporation sphere is changed and the evaporation is performed again in order to make the coating uniform. However, when coating copper 3, the coating is not dense; for example, the evaporation time and surface direction are *Pinholes (6) are intentionally created in undeposited areas by reducing the number of grinds. The reason why we intentionally created a structure with undeposited parts (pinholes) 6 when coating the copper 3 is because lithium generates tritium when irradiated with neutrons, but the copper 3
Since this metal is difficult for tritium to pass through, pinholes are provided to facilitate the release of tritium.

Since nickel gold 1iII3 easily permeates tritium,
Special considerations such as copper are not required.

Reference numeral 4 denotes a copper ball that is vibrated and filled in a metal container (for example, a stainless steel tube) together with the metal-coated lithium ceramic ball.This copper ball 4 has a smaller diameter than the metal-coated lithium ceramic ball ( For example, diameter 0.5~
1 mm) are used, and are mixed and filled at an appropriate volume ratio (for example, 8 lithium ceramic balls: 2 copper balls). In the figure, the copper balls 4 are shown to have substantially uniform grain sizes, but in order to achieve more dense packing, several types of copper balls having different grain sizes may be mixed and used. Although not shown, end plugs with slits or wire mesh are welded to the upper and lower ends of the metal container to hold the lithium ceramic sphere in a predetermined position.

(c) Effects of the invention While conventional blankets simply filled with lithium ceramic balls have extremely low effective thermal conductivity, the present invention has very good thermal conductivity and is made of a relatively soft metal. The surface of the lithium ceramic spheres is coated with copper, and the gaps between the lithium ceramic spheres are filled with copper spheres, so the contact area between the lithium ceramic spheres and between the lithium ceramic sphere and the metal container is large. Therefore, the effective thermal conductivity can be increased by 100 times or more, and the heat removal performance of the plant is improved.

Additionally, during furnace operation, lithium ceramic spheres may lose their shape due to the generation of internal bubbles due to the production of tritium or cracks due to thermal strain, but the metal coating on the sphere's surface has the effect of suppressing the collapse of the sphere.

[Brief explanation of drawings]

The figure is a partial cross-sectional view of the fusion blanket of the present invention. 1... Lithium ceramic ball 2... Nickel metal 3... Copper 4... Copper ball 5... Metal container
6...Undeposited area (pinhole)

Claims (2)

[Claims] (1) After coating a lithium ceramic sphere with nickel metal, a lithium ceramic sphere with a metal coating, which is further coated with copper, and a copper sphere with a smaller diameter than the lithium ceramic sphere are mixed and filled into a metal container. A nuclear fusion blanket characterized by (2) The fusion blanket according to claim 1, wherein the copper has pinholes in its coating layer.