JP2999278B2 - Structure of blanket for fusion reactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tritium breeding blanket in a core structure disposed around a plasma in a fusion reactor.

[0002]

2. Description of the Related Art FIGS. 8 to 10 show JAERI-M87-0.
FIG. 8 shows an example of the conventional breeding blanket shown in FIG.
9 is a perspective sectional view of the blanket, FIG. 9 is an enlarged plan view of a portion C in FIG. 8, and FIG. 10 is a partially enlarged view of a section taken along line bb in FIG. 8 to 10, 51 is a blanket, 52 is a first wall, 53 is a neutron multiplier, 54 is a cooling tube, 55 is a breeding material, 56 is plasma, 57 is a manifold, 58 is a heat resistance layer, and 59 is a spacer. Tube. FIG.
The conventional blanket 51 shown in FIG.
From the first wall 52 facing the first wall 52 to 57 parts of the rear manifold having a thickness of about 60 cm, and from the first wall toward the rear, a neutron multiplier 53 filling portion such as beryllium, lithium oxide, etc. The cooling pipes 54 are disposed at the filling portions of the filling material 55 at a higher density as the distance from the plasma 56 increases, and at a lower density as the distance from the plasma 56 increases.

When tritium is propagated by irradiation from the plasma 56, cooling water is allowed to flow through the cooling pipe 54 to remove heat, and operation is performed while maintaining the temperature of the blanket 51 within a predetermined range. Do, but the blanket 51
During a certain period of time (2 to 3 years), the amount of tritium breeding material such as lithium oxide for breeding tritium decreases as the tritium production reaction proceeds. Also, since the first wall 52, which always faces the hot plasma 56, is gradually damaged by heat and neutron irradiation, it has been necessary to replace the blanket 51 approximately every two to three years.

[0004]

As described above, even in the above-mentioned prior art, tritium is multiplied by plasma irradiation, and high-temperature heat generated from the plasma is used as a heat source for power generation or the like, and tritium is generated after a certain period of operation. The long-term operation of the fusion reactor was made possible by replacing the blanket with a reduced reaction rate.

[0005] However, despite the fact that the reaction rate of tritium generation and the radiation damage rate of the structural material are large on the plasma side and small on the rear side, the rear tritium breeding section where the reaction has not progressed due to the single-piece blanket is also replaced. As a result, there were the following problems.

[0006] It is uneconomical to take out and discard a portion of the blanket, such as lithium oxide or beryllium, which does not need to be replaced, among lithium oxide and beryllium.

The removed blanket container is activated by neutrons and contains tritium, so that the entire blanket container must be treated as radioactive waste, and the amount of radioactive waste increases.

[0008] The size and weight of the handling equipment at the time of replacement by remote control increase, and the handling procedure becomes complicated.

Due to the placement of the shell conductor for plasma position control in the blanket vessel, this may absorb neutrons emitted from the plasma and affect tritium breeding performance.

Since strong electromagnetic force acting on the shell conductor during plasma disruption directly acts on the thin plasma facing surface (first wall), the soundness of the container may be reduced.

An object of the present invention is to solve the above-mentioned problems and to provide a blanket which is simple, has a high reliability, is economically excellent, and reduces the amount of radioactive waste.

[0012]

The above objects are achieved by the structure of a blanket for a fusion reactor as set forth in the appended claims. That is, a fusion reactor having a first wall on the plasma side and an exchange blanket portion having a cooling tube formed in the neutron multiplier and breeding material, and a permanent blanket portion having a cooling tube formed in the breeding material. The structure of the blanket.

The operation and the like of the present invention will be described below based on embodiments.

[0014]

1 to 7 show an embodiment according to the present invention. FIG. 1 is a perspective sectional view of a blanket composed of an exchange blanket and a permanent blanket in a separated state, and FIG. A part enlarged plan view, FIG. 3 is a B part enlarged plan view in FIG. 1, FIG. 4 is a sectional view taken along line aa of FIG. 1, FIG. 5 is a combination of the replacement blanket and the permanent blanket in FIG. FIG. 6 is an overall longitudinal sectional view of a fusion reactor to which a blanket according to the present invention is applied, and FIG. 7 is a partial longitudinal sectional view of a fusion reactor to which a blanket according to the present invention is also applied. 1 to 7, 1 is a replacement blanket, 2 is a permanent blanket, 3
Is the first wall, 4 is the first breeding area, 5 is the second breeding area, 6 is the neutron multiplier, 7 is the electric resistance section, 8 is the shell conductor, 9,
9 ', 9 "are heat resistance layers, 10 and 10' are manifolds, 1
1 is a cooling pipe, 12 is a breeding material, 13 is a surface protective coating, 14 is a vacuum vessel (shield), 15 is a toroidal coil, 16 is a poloidal coil, 17 is a diverter, 1
8 is the inner blanket, 19 is the outer blanket, 20
Is a heating device, 21 is a limiter, 22 is an exhaust duct, and 23 is plasma.

The reaction rate at which neutrons are irradiated from the plasma 23 to generate tritium is large on the plasma 23 side.
It becomes smaller as the distance from the plasma 23 increases. The present invention focuses on this difference in the reaction rate, and divides the blanket into two parts, a side close to the plasma 23 and a rear side, and sets the plasma 23 side as an exchange blanket 1 and the rear side as a permanent blanket 2. And

The thickness of the exchange blanket 1 is set so that the neutron flux attenuates by about one digit (about 150 mm to 200 mm). For example, in the case of an outer blanket having a total blanket thickness of 600 mm, the replacement blanket 1 is set to about 200
mm thickness and the permanent blanket 2 is about 400 mm thick.

In FIG. 1 to FIG.
The first wall 3 is disposed on the side facing the plasma 23. First
As shown in FIG. 4, a large number of cooling pipes 11 are arranged adjacent to each other on the entire surface of the wall 3, and a surface protective coating 13 is provided on the side of each cooling pipe 11 facing the plasma 23. Behind the first wall 3, a first breeding area is first formed,
Further, a neutron multiplier 6 such as beryllium is provided via a cooling pipe 11 provided in contact with the heat resistance layer 9 provided in an airtight manner. In the rear, a second breeding region 5 is formed with a cooling pipe 11 disposed in contact with the heat-resistant layer 9 provided in the same manner as described above in an airtight manner. A plurality of cooling pipes 11 are provided so as to be inscribed in the heat resistance layer 9 ". A rear wall of the exchange blanket 1 shown in FIG. The electric resistance part 7 is buried.

The permanent blanket 2 is provided so that a number of cooling pipes 11 are arranged adjacent to the outer periphery, a shell conductor 8 is provided behind the cooling tube 11, and a heat resistance layer 9 'is further provided behind the shell conductor 8. A breeding zone filled with a breeding material 12 is formed in the space surrounded by the ′ ′, and a plurality of cooling pipes 11 inscribed and inserted in the tubular heat resistance layer 9 ″ as shown in FIG. The cooling pipe 11 is provided with a plasma 23.
Are arranged densely on the side closer to the plasma and conversely, coarsely on the side farther from the plasma 23.

FIG. 5 is a perspective view showing a state in which the exchange blanket 1 and the permanent blanket 2 shown in FIG. 1 are connected. The connection of the blankets 1 and 2 is performed, for example, by providing a fitting portion on each of the blankets 1 and 2. Then, a high-pressure gas is supplied to the fitting portion to be pressed. When the connected blankets are detached, the high-pressure gas is discharged to release the press-fitting of the fitting portion and separate the blanket, for example, by a detachable method.

When installing the permanent blanket 2 in a fusion reactor, the permanent blanket 2 in a separated state is first carried in, and placed in a vacuum vessel (shield) 14 shown in FIG. Install it firmly. Next, the exchange blanket 1 is carried in, and bonded to the permanent blanket 2 by the above-described method or the like.

During operation for a certain period of time, the tritium breeding material decreases due to the progress of the tritium generation reaction and becomes difficult to react, and the first wall 2 is damaged by a high heat load from plasma and neutron irradiation. At this time, the replacement blanket 1 is separated from the permanent blanket 2 and carried out of the furnace, and a new replacement blanket 1 is carried into the furnace and combined with the permanent blanket 2. For the permanent blanket 2, the neutron irradiation dose is reduced by one digit by the exchange blanket, the heat radiation from the plasma is shielded by the exchange blanket 1, and the tritium generation reaction rate is smaller than that of the exchange blanket 1. Since the breeding material decreases only slightly, it can function satisfactorily during the life of the fusion reactor even if it is used continuously without replacement.

[0022]

As described above, according to the present invention, the following effects can be obtained as apparent from the above embodiment.

Suffering radiation damage by neutron irradiation,
Also, by replacing only the blanket in which the tritium production reaction has progressed and the tritium breeding material has been reduced, waste material of the breeding material or the neutron doubling material can be prevented from being wasted, and the economy can be improved.

Although the removed blanket container is activated by neutrons, the amount of radioactive waste can be significantly reduced because the replacement blanket is about one-third the size of the whole.

Since the size and weight of the blanket to be replaced is reduced as compared to the entire handling,
Exchange by remote control becomes easy.

Since the shell conductor is disposed in the rear permanent blanket container, it is possible to prevent the proliferation performance from being reduced, and the permanent blanket container can have a thick and solid reinforcing structure. In addition to preventing the soundness of the first wall from deteriorating, the first wall can be prevented from being broken by the electromagnetic force during plasma disruption.

The replacement of the first wall which is damaged facing the plasma can be performed economically with good exchangeability since only the exchange blanket needs to be exchanged.

[Brief description of the drawings]

FIG. 1 is a perspective sectional view of a blanket in a separated state.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a partially enlarged view of FIG. 1;

FIG. 4 is a partially enlarged view of FIG. 1;

FIG. 5 is a perspective cross-sectional view of the blanket in a connected state.

FIG. 6 is an overall longitudinal sectional view of a fusion reactor equipped with a blanket according to the present invention.

FIG. 7 is a partial longitudinal sectional view of FIG.

FIG. 8 is a perspective sectional view of a conventional breeding blanket without using the present invention.

FIG. 9 is an enlarged plan view of a portion C in FIG. 8;

FIG. 10 is a partially enlarged view of a section taken along line bb in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exchange blanket 2 Permanent blanket 3 1st wall 4 1st breeding area 5 2nd breeding area 6 Neutron multiplier 7 Electric resistance part 8 Shell conductor 9 Heat resistance layer 9 'Heat resistance layer 9 "Heat resistance layer 10 Manifold 10' Manifold 11 Cooling pipe 12 Breeder 13 Surface protective coating 14 Vacuum container (shield) 15 Toroidal coil 16 Poloidal coil 17 Divertor 18 Inner blanket 19 Outer blanket 20 Heating device 21 Limiter 22 Exhaust duct 23 Plasma 51 Blanket 52 First wall 53 Neutron enhancement Double material 54 Cooling tube 55 Breeding material 56 Plasma 57 Manifold 58 Heat resistance layer 59 Spacer tube

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasushi Seki 801 Mukaiyama, Naka-machi, Naka-machi, Naka-gun, Ibaraki Pref. (1) Naka Research Institute of Japan Atomic Energy Research Institute (56) References JP-A-61-231481 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G21B 1/00

Claims (1)

(57) [Claims] 1. An exchange blanket part having a first wall on a plasma side and having a cooling pipe formed in a neutron multiplier and a breeder,
A blanket structure for a fusion reactor, comprising: a permanent blanket portion in which a cooling pipe is formed in a breeding material.