JP2003279681A - High temperature heat flux removing device using free surface fluid with secondary flow - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high temperature heat flux removing device using a free surface fluid with secondary flow, characterized in that it is provided with a secondary flow generator for forcibly generating the secondary flow on fluid metal or molten salt to remove the heat flux flowing on the upper face of a solid wall of the lower part of a plasma chamber mounted in a vacuum vessel of a nuclear fusion reactor, and improving the heat conductive property. <P>SOLUTION: In this high temperature heat flux removing device using the free surface fluid with secondary flow, is characterized in that an electrically driven water turbine or torsion tape is mounted on the upper face of the solid wall of the lower part of the plasma chamber mounted in the vacuum vessel of the nuclear fusion reactor to configurate the secondary flow generator for stirring the liquid metal or molten salt to remove the heat flux from the plasma, and the secondary flow is forcibly generated on the liquid metal or molten salt to improve its heat conductive property. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for efficiently removing a high heat flux in an environment exposed to the high heat flux. In particular, the present invention forcibly generates a secondary flow in a liquid metal or molten salt for heat flux removal, which is caused to flow on a solid wall under a plasma chamber provided in a vacuum vessel of a fusion reactor, and transfers the secondary flow. The present invention relates to a high heat flux removing device using a free liquid surface fluid with a secondary flow, which is provided with a secondary flow generator for improving thermal characteristics.

[0002]

2. Description of the Related Art As a divertor of a tokamak-type fusion reactor, which is a typical high heat flux removing device, a heat flux from plasma is formed by joining an armor material such as tungsten on a diverter plate made of copper alloy or the like. A solid wall diverter that removes is common.

[0003]

In the fusion power reactor, it is required to make the shape of the reactor compact and increase the fusion output in order to improve the economical efficiency, so that the heat flux from the plasma becomes high. , Solid wall diverter, 20MW from the viewpoint of severe mechanical mechanical condition such as thermal stress
There is a problem that it becomes extremely difficult to remove a high heat flux exceeding / m ² .

As one solution to such a problem, a liquid metal such as lithium or gallium or a molten salt F is formed on the solid wall.
A liquid diverter has been proposed in which a liquid such as LiBe (Freebe: a mixed salt of LiF and BeF ₂ ) is flowed as it is to remove heat. However, in these proposals, when liquid metal or molten salt FLiBe is caused to flow in a laminar flow state on a solid wall, only the surface of the liquid film exposed to the heat flux becomes high in temperature, the saturated vapor amount increases, and it enters the plasma. There is a problem that the heat removal limit is equal to or less than that of the solid wall diverter from the viewpoint of inclusion of impurities.

In the conventional research, in order to accelerate the heat removal from the surface of the liquid film, a turbulent mixing method utilizing waviness on the free liquid surface, and a passive secondary flow utilizing centrifugal force or temperature difference convection. Has been proposed.

[0006]

In order to solve the above-mentioned problems, a high heat flux removing device using a free surface fluid with a secondary flow according to the present invention is a liquid metal or a molten metal flowing on an inclined solid wall. Liquid metal or molten metal that forces a secondary flow in the salt to improve heat transfer characteristics and absorbs high heat flux throughout the liquid film, which can be effectively carried out of the fusion reactor and removed. It is characterized in that a forced secondary flow is generated in the main stream of salt.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS It is known that when the flow is a laminar flow, a remarkable heat transfer promotion effect can be obtained by generating a secondary flow in the flow path. It is known that the spiral tube or the twisted tape inserted in the tube is particularly effective in the case of a liquid having a high Prandtl number. In the present invention, this idea is applied to the free liquid surface fluid.

When a fluid having a high Prandtl number (a fluid having a high viscosity and a thick viscosity) such as FLiBe molten salt is used as a free liquid surface fluid, as a measure for improving the heat transfer characteristics, the liquid on the wall surface where the liquid flows is used. It is effective to arrange a twisting tape or a water wheel on the surface of the turbine and rotate it electrically from the outside to generate a forced secondary flow of the fluid. The apparent heat transfer characteristics can be improved by circulating the liquid heated to a high temperature by the heat flux from the plasma on the free surface in a downward swirl flow.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiments. (Embodiment 1) First, referring to FIG. 1, this figure is a schematic view of the entire structure of a high heat flux removing apparatus using a free surface fluid with secondary flow according to the present invention, taking a fusion reactor as an example. It is shown. That is, it is an elevational piece cross-sectional view of a structure in which a free liquid surface fluid is made to flow under a plasma chamber in a vacuum container of a tokamak fusion device.

In FIG. 1, the liquid injection port 3 is made to continuously make one round in the torus direction on the lower side of the plasma chamber 2 in the vacuum container 1 on the inboard side and the outboard side. The liquid metal or the molten salt 4 flowing in from the inlet absorbs the heat flux, tritium, etc. from the plasma 6 and is forcibly discharged from the outlet 5 together with impurities. In the present invention, a high heat flux removing device that uses a secondary flow generator for the liquid metal or molten salt that has flowed in from this inlet is installed.

(Embodiment 2) FIG. 2 is an enlarged conceptual view of the relationship between the plasma heat flux 11 and the high heat flux removing device using the free liquid surface fluid 13 with secondary flow. There is. That is, it is a conceptual cross-sectional view showing the relationship between the free liquid surface fluid with secondary flow, the secondary flow generator, and the solid wall.

Referring to FIG. 2, the principle and operation of the high heat flux removing apparatus using the free liquid surface fluid with secondary flow will be described. On the inclined solid wall 14 corresponding to the lower part of the plasma chamber of FIG. A secondary flow generator (for example, a water wheel or a twisting tape) 16 is installed, and the liquid metal or the molten salt flows from above along the inclined solid wall 14 by gravity. The heat flux 11 flowing from the free liquid surface 12 is
The secondary flow generator 16 is rotated by driving a power source from the outside to diffuse the secondary flow generator 16 over the entire liquid film. A cooling passage 15 is formed in the solid wall 14 in order to remove a heat flux flowing through the liquid.

(Embodiment 3) FIG. 3 shows a conceptual diagram in which a twisting tape 21 as a secondary flow generator which is a part of the present invention is installed on an inclined solid wall 22 corresponding to the lower part of the plasma chamber. . That is, it is a conceptual application diagram showing the relationship between the free liquid surface fluid flowing on the solid wall 22 and the secondary flow generator 21 made of a torsion tape.

The liquid metal or molten salt 24 flowing in from the liquid inlet 23 absorbs the high heat flux 27 with the secondary flow 25 generated by driving the electric tape 28 from the outside of the twisted tape 21, and the outlet 26. Drains from.

[0015]

INDUSTRIAL APPLICABILITY When the present invention is applied to a fusion reactor, a free secondary surface fluid having a high Prandtl number, such as FLiBe molten salt, which receives a heat flux, causes a forced secondary flow to lower the temperature of the liquid surface, A high heat flux exceeding 20 MW / m ² can be removed. In the analysis, when FLiBe molten salt was used,
As a result of simulating the effect of the secondary flow with an equivalent thermal conductivity of 10 kW / mK, the heat transfer characteristics are improved 3 to 4 times by generating the secondary flow, and the heat flux of 100 MW / m ² can also be removed. I knew that.

[Brief description of drawings]

FIG. 1 is an elevational sectional view of a structure in which a high heat flux removing device using a free liquid surface fluid is attached to the lower part of a plasma chamber in a vacuum container of a tokamak fusion device.

FIG. 2 is a conceptual cross-sectional view of a high heat flux removing device using a free surface fluid with secondary flow and a solid wall.

FIG. 3 is a conceptual application diagram in which a secondary flow generator made of a twisted tape is installed on an inclined solid wall corresponding to the lower part of the plasma chamber.

[Explanation of symbols]

1: vacuum container, 2: plasma chamber, 3: liquid inlet, 4: liquid metal or molten salt, 5: outlet, 6: plasma, 7: tokamak fusion reactor torus center line, 1
1: Heat flux, 12: Free liquid surface, 13: Liquid metal or molten salt, 14: Solid wall, 15: Cooling channel, 16: Secondary flow generator (turbine), 21: Secondary flow generator (torsion) Tape), 22: inclined solid wall, 23: liquid inlet, 2
4: Liquid metal or molten salt, 25: Secondary flow, 26: Discharge port, 27: High heat flux, 28: Electric motor, 29: Power supply

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[Procedure amendment]

[Submission date] April 3, 2002 (2002.4.3)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

As one solution to such a problem, a liquid metal such as lithium or gallium or a molten salt F is formed on the solid wall.
A liquid diverter has been proposed in which a liquid such as LiBe (Freebe: a binary mixed salt of LiF and BeF ₂ ) is flowed as it is to remove heat. However, in these proposals, when liquid metal or molten salt FLiBe is caused to flow in a laminar flow state on a solid wall, only the surface of the liquid film exposed to the heat flux becomes high in temperature, the saturated vapor amount increases, and it enters the plasma. There is a problem that the heat removal limit is equal to or less than that of the solid wall diverter from the viewpoint of inclusion of impurities.

Claims (3)

[Claims] 1. A free level fluid with secondary flow, comprising a secondary flow generator provided on an inclined solid wall and a free liquid surface fluid consisting of liquid metal or molten salt flowing on the inclined solid wall. High heat flux removal device used. 2. The device according to claim 1, wherein the secondary flow generator provided on the inclined solid wall is a water wheel or a twisting tape. 3. A secondary flow generator for agitating liquid metal or molten salt for removing heat flux from plasma is provided on a solid wall under a plasma chamber provided in a vacuum vessel of a fusion reactor. , An electrically driven water turbine or a twisting tape is arranged to forcibly generate a secondary flow in the liquid metal or molten salt to improve the heat transfer characteristics thereof, and a free liquid surface fluid with a secondary flow. High heat flux removal device using.