JP2858191B2 - Fusion reactor blanket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blanket of a fusion reactor, and more particularly to a structure of a blanket of a fusion reactor which can reduce the influence of heat deformation on heat transfer characteristics and is easy to manufacture. .

[0002]

2. Description of the Related Art Various types of blankets for a fusion reactor have been devised, and one of them is a pin type blanket.

FIG. 9 is a view showing the structure of an example of a conventional pin type blanket. A large number of blanket pin modules 2 are installed inside the blanket container 1, and each blanket pin module 2 is formed of a quadruple tube as shown in FIG. The tritium breeding material coating tube 5 at the center is filled with the tritium breeding material 4. A helium gap 9 is provided outside the helium gap 9, and a spacer 10 is provided inside the helium gap 9, and a layer of the coolant 3 is partitioned by an inner cooling pipe 11. Outside, an outer cooling pipe 12 partitions the neutron multiplier 6,
There is a pin module cladding tube 7 on the outermost side.

In the nuclear fusion reaction, a reaction is performed as follows: D + T = n + α (1), one tritium is consumed, and one neutron is emitted. Tritium, one of the fuels,
Because it is a nuclide that does not exist in nature, to maintain the fusion reaction,
Using this neutron, the fusion reactor itself must produce tritium. Therefore, in the blanket,
It is filled with lithium or its compound that reacts with neutrons to produce tritium.

In general, the ratio between the consumption rate of tritium consumed in a nuclear fusion reaction and the production rate of tritium in a blanket is called a tritium breeding ratio. In a fusion reactor, (1)
Since one tritium is consumed and one neutron is emitted as shown in
It can produce more tritium than consumed tritium. In addition, in order to construct a new fusion reactor, tritium for loading at the beginning of operation is necessary. Considering that tritium is also produced, the tritium breeding ratio is
1 is required to exceed about 10%. Since tritium is a radionuclide and has a half-life of 12 years, the produced tritium decreases year by year. In consideration of this point, the tritium breeding ratio is required to exceed 1 by about 10%.

In a fusion reactor blanket, neutrons generated by a fusion reaction react with lithium to produce tritium as follows.

⁶ Li + n = T + α (2) ⁷ Li + n = n ′ + T + α (3) In the reaction of (2), ⁶ Li is a thermal neutron. Has a large tritium production reaction cross section of 940 burns. This cross-sectional area changes by 1 / v, where neutron velocity is v, and 2
The reaction has a resonance of 3.5 burns at a neutron energy of 50 keV. For this reason, the reaction becomes easier when the neutron energy is lower.

[0008] The reaction of the other hand (3), a reaction for producing a product to and neutrons tritium, the neutron again ⁶
The reaction of Li with (2) produces tritium. By these two reactions, there is a possibility that tritium may be produced in an amount greater than that consumed in the DT reaction (1). However, ⁷ Li has a tritium generation reaction cross section of 0.5 burn and a threshold value of 2.5 MeV, and the tritium breeding ratio does not greatly exceed 1. Therefore, most blankets use neutron multipliers, which are beryllium or lead or a compound thereof, to convert neutrons generated by a fusion reaction into Be + n = 2n + 2α as follows. 4) After increasing the neutrons by reacting with the neutron multiplier, ⁶ Li
To improve the tritium breeding ratio.

For this reason, in the conventional blanket, the pin module is provided with a layer of the neutron multiplier 6. Water is used for the coolant 3 on the inner side, and the temperature of the water during the operation is set to 1 to 1 depending on the purpose of the fusion reactor.
It is designed to have a temperature range of 00 ° C (blanket for tritium production only without power generation) and up to 300 ° C (blanket for power generation and tritium production).

However, in order to release the generated tritium from the tritium breeding material 4, a temperature of 450 ° C. or more is required depending on the type of the material. On the one hand, it must be operated at 850 ° C. or lower due to the integrity of the tritium breeder itself. That is, during the operation of the nuclear fusion reactor, the tritium breeding material 5 must be used in the range of 450 ° C. to 850 ° C. Therefore, between the temperature of the coolant 3 and the temperature of the tritium breeding material 4 is ~ 350 ° C.
Or there is a temperature difference of １５０150 ° C.

In order to make this temperature difference, in the conventional blanket, between the coolant 3 and the tritium breeding material 4,
A helium gap 9 having a width of 1 mm is provided. Also,
In the conventional blanket, lithium aluminate LiAlO ₂ is used for the tritium breeding material 4 and beryllium is used for the neutron multiplier 6. Lithium aluminate and beryllium have poor coexistence at high temperatures, so they must be used separately. In a conventional blanket, a tritium breeding material is mounted in the center and a neutron multiplier is mounted in the outermost layer as shown in FIG. From such an idea, the conventional blanket has a quadruple tube structure.

The equatorial section of the conventional blanket shown in FIG. 9 has a height of 8 m above and below the poloidal section of the fusion reactor.
Is continuous.

[0013]

In the above-mentioned conventional blanket, a temperature difference of .about.350.degree. C. or .about.150.degree. C. between the temperature of the coolant 3 and the temperature of the tritium breeding material 4 is obtained by a helium gap having a width of 1 mm. Therefore, when the helium gap width changes due to thermal deformation, the temperature characteristics of the tritium breeding material change significantly. In particular, when the gap width is 1
Due to the small size of mm, the change in the temperature characteristics of the tritium breeding material is sensitive to the change in the gap width. Since the temperature difference between the gaps is approximately inversely proportional to the gap width, if the gap width is considered to change by 0.5 mm, the temperature difference between the coolant 3 and the tritium breeding material 4 is ~ 350 ° C. ± 175 ° C.
Alternatively, the temperature is ℃ 150 ° C. ± 75 ° C.

Considering the case where the gap width is reduced from 1 mm to 0.5 mm, ie, −175 ° C. or −75 ° C., the minimum temperature of the tritium breeding material 4 is 275 ° C. or 375 ° C., respectively. It is difficult to recover the waste. In order to design the pin module so that tritium can be recovered even in such a case, the minimum temperature of the tritium breeding material 4 during operation must be set higher. That is, it is necessary to set 450 ° C. + 175 ° C. = 625 ° C. (blanket for tritium breeding only) 450 ° C. + 75 ° C. = 525 ° C. (blanket for power generation and tritium breeding).

On the other hand, considering the case where the gap width is increased from 1 mm to 1.5 mm, that is, considering + 175 ° C. or + 75 ° C., the maximum temperature of the tritium breeding material 4 during operation is 1025 ° C. or 1025 ° C., respectively. 925
° C, compromising the integrity of the tritium breeder. To avoid this, the maximum temperature during operation of the tritium breeder 4 must be set lower. That is, the design values must be set so that 850 ° C.-175 ° C. = 675 ° C. (blanket for tritium breeding only) 850 ° C.-75 ° C. = 775 ° C. (blanket for power generation and tritium breeding).

As described above, when the minimum temperature and the maximum temperature of the tritium breeding material 4 during operation are compared, the temperature range of the tritium breeding material 4 during operation is 525 ° C. 775 ° C and 250
There is room for ° C. However, in the case of a blanket for the purpose of producing only tritium without generating power, the temperature range during operation of the tritium breeding material 4 is 625 ° C. to 675 ° C.
Only margins of 50 ° C. and 50 ° C. are allowed. 8m up and down
It is very difficult in production to suppress the thermal deformation to 0.5 mm or less.

As described above, the conventional blanket has a disadvantage that it is easily affected by thermal deformation. In addition, since the pin module has a structure in which a triple tube including a 1 mm gap is inserted inside a circular tube having a diameter of less than 5 cm,
There is a disadvantage that it is difficult to manufacture a large number of pin modules with a predetermined accuracy.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fusion reactor blanket with high manufacturability by reducing the influence of heat deformation on heat transfer characteristics and simplifying the structure.

[0019]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention produces tritium, which is one of the fuels of a fusion reactor consumed by a fusion reaction in a plasma confined by a magnetic field. A cooling structure that houses a tritium breeding material to increase the tritium production efficiency, a neutron multiplier to increase tritium generation efficiency, and a coolant that converts the kinetic energy of neutrons generated by the fusion reaction to heat energy and extracts this heat. In a blanket of a fusion reactor installed in a region close to the plasma, a tube filled with any one of tritium breeder, neutron multiplier and coolant is placed in the blanket container. And a blanket for a fusion reactor in which the space between the tube and the blanket container is filled with the remaining material.

According to the present invention, the inner tube is filled with a tritium breeding material and the outer tube is filled with a neutron multiplier.
The present invention proposes a fusion reactor blanket in which a heavy pipe is mounted in a blanket vessel and a space between the double pipe and the blanket vessel is filled with the coolant.

[0021] The present invention further double tube filled with neutron multiplier material mounted in the blanket container filled with the coolant inside the tube to the tube of its outer, between the double pipe and the blanket container This proposal proposes a blanket for a fusion reactor in which the space is filled with tritium breeding material .

[0022] In blanket fusion reactors filled in the space between the coolant and the tube and the blanket container, spacers for supporting the double tube or between calandria tubes each other in a coolant, the distribution in the flow of coolant Can be provided.

According to the present invention, a tube filled with a coolant and a tube filled with a tritium breeding material are respectively mounted in a blanket container, and a space between each tube and the blanket container is filled with a neutron multiplier. It proposes a blanket for a fusion reactor .

In each case, the tritium breeding material is specifically a pebble or pellet of lithium or a lithium compound, and the neutron multiplier is specifically a pebble or pellet of beryllium and / or lead. is there. These pebbles or pellets can be pebble or pellets with controlled pore density to control heat transfer properties.

[0025]

In the fusion reactor blanket of the present invention,
Fill the blanket container with one of the tritium breeder, neutron multiplier and coolant, and install a tube filled with the remaining material in the blanket container. Adopting a structure in which a neutron multiplier is interposed,
~ 35 between the temperature of the coolant and the temperature of the tritium breeder
A temperature difference of 0 ° C. or １５０150 ° C. has been obtained through the neutron multiplier beryllium. In this case, since the layer of beryllium, which is a neutron multiplier, has a thickness of at least 10 mm or more, even if the thickness changes by, for example, about 1 mm due to thermal deformation, the effect on the heat transfer characteristics is small. Further, since the pin structure is at most a double tube, manufacture is easy.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a blanket for a fusion reactor according to the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an equatorial section of a blanket of a fusion reactor of the present embodiment. Neutrons are emitted from the plasma on the left side of the figure. A pin module 2 is mounted in the blanket container 1, and a space between the pin module 2 and the blanket container 1 is filled with water 3 as a coolant.

FIG. 2 is a view showing the structure of the pin module 2. The tritium breeding material cladding tube 5 is filled with lithium zirconate 4 which is a tritium breeding material.
Centering on the tritium breeding material cladding tube 5, the pin module cladding tube 7 is filled with neutron multiplier 6 beryllium.

The neutron flux having an energy of 14 MeV from the plasma is 4.4 × 10 ¹³ n / cm ² s, and a part thereof is decelerated or absorbed by the first wall on the plasma side of the blanket container 1. . As a result, when the first wall is made of stainless steel and cooled by water, the nuclear heat generation on the first wall is about 15 W / cm ³ . Some of the neutrons that escaped absorption at the first wall and were decelerated were decelerated by the water that is the coolant 3, and a part of the kinetic energy they had was reduced by 7 to
Emitted as nuclear heat of 8 W / cm ³ . The neutrons that have passed through the water region near the first wall react with beryllium, which is the neutron multiplier 6, as shown in the above equation (2), and multiply the neutrons. Beryllium is also a good neutron moderator,
Kinetic energy is released in the process of neutron deceleration in beryllium, but the reaction of equation (2), which is a neutron multiplication reaction, is an endothermic reaction. The calorific value is 2 near the first wall.
It is about ³ W / cm ³ .

The neutrons that have passed or been slowed down by beryllium and the neutrons multiplied by beryllium react with the tritium breeder 4 as shown in the above formulas (2) and (3) to produce tritium. Since the energy of many neutrons that have passed through beryllium is lower than the threshold value of the reaction of equation (3), 2.5 MeV, the proportion of the reaction of equation (3) in the tritium formation reaction is as small as several percent, In most cases, the reaction is as shown in equation (2). The reaction of the formula (2) is an exothermic reaction, and is performed in a single reaction.
Emit energy of 8 MeV. In the blanket of the fusion reactor of the present embodiment, when lithium zirconate Li ₂ ZrO ₃ is used as the tritium breeding material 4, the nuclear heat generation of lithium zirconate Li ₂ ZrO _{3 in} the region near the first wall is 〜25 W / cm ³ .

Considering such nuclear heating conditions, during operation of the fusion reactor, the tritium breeding material 5 is maintained at 450 ° C. to 85 ° C.
It must be used in the range of 0 ° C. The size of the pin module 2 for satisfying the requirement of this temperature range under the nuclear heating conditions is as follows. The diameter of the pin module 2 shown in FIG. 2 ～50Mm, tritium breeder 4
The diameter of lithium zirconate is ~ 20 mm, the thickness of the tritium breeding material cladding tube 5 is 1 mm, the thickness of beryllium which is the outer neutron multiplier 6 is ~ 15 mm, and the outermost is the pin module cladding tube 7. The thickness is 1 mm.

In the blanket of the fusion reactor comprising the pin module group having such a configuration, the temperature of the coolant 3 is set to 10
Even when the temperature is set to 0 ° C., the temperature difference is 350 ° C. between the lowest temperature of the tritium breeding material 4 during operation of 450 ° C., and this temperature difference can be achieved by the neutron multiplier 6 layer. Assuming that the thickness of the layer of the neutron multiplier 6 changes by 1 mm due to thermal deformation, the change ΔT in the temperature difference is at most 23 ° C., such as ΔT = 350/15 = 23 ° C. Therefore, the design temperature is set to ５5 so that the minimum temperature during the operation of the tritium breeding material 4 is not lower than 450 ° C.
The temperature may be set to about 00 ° C. and the structure of the pin module 2 may be determined. The pin module 2 has a structure in which a tube having a thickness of 1 mm and a diameter of 2 cm is inserted into a tube having a thickness of 1 mm and a diameter of 5 cm.
Is easy to manufacture.

Each of the pin modules 2 is mutually supported by pin module spacers 8 as shown in FIG. The pin module spacer 8 is a pin module 2 having a length of 8 m.
In some places to keep the pin modules 2 spaced from each other. The cross-sectional shape of the pin module spacer 8 may be changed according to the installation location in order to distribute the flow of the coolant.

In this embodiment, the individual pin modules 2 are mounted in the blanket container 1.
Several pin modules 2 may be put together in a so-called calandria tube, and the calandria tube may be stored in the blanket container 1.

With reference to FIGS. 4 and 5, another embodiment of the blanket of the fusion reactor according to the present invention will be described. FIG.
FIG. 3 is a diagram showing an equatorial section of a blanket of the fusion reactor of the present embodiment. Neutrons are emitted from the plasma on the left side of the figure. The interior of the blanket 1 container is filled with a tritium breeding material 4, and a number of pin modules 15 including a coolant and a neutron multiplier are mounted therein.

The pin module 15 including the coolant and the neutron multiplier has a structure as shown in FIG. In other words, the inner
Side cooling pipe 11 water occupies a coolant 3, the space between the inner cooling tube 11 and the pin module cladding 7, beryllium is filled a neutron multiplier material 6.

In the fusion reactor blanket of this embodiment, the distance between the tritium breeder 4 and the coolant 3 is 1 cm.
Therefore, even when considering a blanket for the purpose of tritium production only and no power generation, the effect of thermal deformation on the temperature difference of 350 ° C during operation is about ± 30 ° C. It is possible to do. In addition, it is structurally constituted by a double tube,
It is easier to manufacture than heavy pipes.

Referring to FIGS. 6 to 8, another embodiment of the fusion reactor blanket according to the present invention will be described. FIG.
It is a figure showing the equator section of the blanket of the fusion reactor of this example. Neutrons are emitted from the plasma on the left side of the figure. The blanket container 1 contains a cooling pin module 1
3 and a tritium breeding pin module 14 are mounted, and the remaining space is filled with beryllium 6, which is a neutron multiplier.

FIG. 7 is a view showing a cross section of the cooling pin module. The water 3, which is a cooling coolant, flows through the inside of the pin module covering tube 7 which also serves as a cooling tube.

FIG. 8 is a diagram showing a cross section of a tritium breeding pin module. The tritium breeder 4 is filled in the pin module cladding tube 7.

In the blanket of the fusion reactor of the present embodiment, the distance between the tritium breeding material 4 and the cooling material 3 is 1 cm.
Even when considering a blanket for the purpose of tritium production only and no power generation, the temperature difference between the two during operation is 3
Since the influence of thermal deformation on 50 ° C. is about ± 30 ° C., it is possible to design in consideration of this. Structurally, it is a simple single tube and easy to manufacture.

In each of the examples, beryllium, lithium and their compounds are formed into pebbles or pellets. At that time, the porosity may be adjusted to control the thermal conductivity.

[0042]

According to the present invention, one of the coolant, the tritium breeding material, and the neutron multiplier is filled in a blanket container, and a tube filled with the remaining two materials is installed therein. And adopting a structure in which a neutron multiplier is interposed between the coolant and the tritium breeding material, at least 10 mm
The neutron multiplier is cooled through the neutron multiplier having the above thickness, and a predetermined temperature difference between the temperature of the coolant and the temperature of the tritium breeder is obtained. 1m by
Even if the thickness changes by about m, the influence on the heat transfer characteristics is small.
Further, in the blanket of the nuclear fusion reactor of the present invention, the blanket is constituted by an aggregate of pin-type tube groups of at most double pipes, and is easy to manufacture.

[Brief description of the drawings]

FIG. 1 is an equatorial sectional view of one embodiment of a blanket of a fusion reactor according to the present invention.

FIG. 2 is a sectional view of the pin module of the embodiment of FIG. 1;

FIG. 3 is a view showing an example of a pin module spacer supporting the pin module tube of the embodiment of FIG. 1;

FIG. 4 is an equatorial sectional view of another embodiment of the blanket of the fusion reactor according to the present invention.

FIG. 5 is a sectional view of the pin module of the embodiment of FIG. 4;

FIG. 6 is an equatorial sectional view of another embodiment of the blanket of the fusion reactor according to the present invention.

FIG. 7 is a sectional view of the cooling pipe pin module of the embodiment of FIG. 6;

8 is a sectional view of the tritium breeding pin module of the embodiment of FIG. 6;

FIG. 9 is an equatorial sectional view of a blanket of a conventional fusion reactor.

FIG. 10 is a cross-sectional view of a pin module used for a blanket of the conventional fusion reactor shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Blanket container 2 Blanket pin module 3 Coolant 4 Tritium breeding material 5 Tritium breeding material cladding tube 6 Neutron multiplier 7 Pin module cladding tube 8 Pin module spacer 9 Helium gap 10 Spacer 11 Inner cooling tube 12 Outer cooling tube 13 Cooling Pin Module 14 Pin Module for Tritium Breeding 15 Pin Module for Cooling and Neutron Multiplication

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tatsuo Amada 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Inside the Hitachi Plant (72) Yoshihiro Ozawa 3-1-1, Sachimachi, Hitachi-shi, Ibaraki No. 1 Hitachi, Ltd. Hitachi Plant (72) Inventor Tatsuhiko Uda 1168 Moriyamacho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Energy Research Laboratories (72) Inventor Michio Otsuka 1168 Moriyamacho, Hitachi City, Ibaraki Hitachi, Ltd. Within the Energy Research Laboratory (72) Inventor Takeshi Nitawaki 3-1-1, Komachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd.Hitachi Plant (72) Inventor Hiroshi Yoshida 801-81 Mukoyama, Nakamachi, Naka-gun, Naka-gun, Ibaraki 1 (72) Inventor Mikio Enoe, No. 801 Mukaiyama, Nakamachi, Naka-gun, Ibaraki Pref. No. 1 Naka Research Institute of Japan Atomic Energy Research Institute (72) Inventor Hideyuki Takatsu 801 Mukaiyama, Naka-cho, Naka-gun, Naka-gun, Ibaraki Pref. 1 Inside Naka Research Institute of Japan Atomic Energy Research Institute (56) References JP 61-104293 (JP, A) JP-A-61-202187 (JP, A) JP-A-61-231481 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G21B 1/00

Claims (10)

(57) [Claims] 1. A tritium breeding material for producing tritium, which is one of the fuels of a fusion reactor consumed by a fusion reaction in plasma confined by a magnetic field, and a neutron multiplier for increasing tritium generation efficiency A blanket container having a cooling structure for storing therein a doubler and a coolant that converts kinetic energy of neutrons generated in a nuclear fusion reaction into heat energy and takes out the heat is provided, and is installed in a region close to the plasma. In a blanket for a fusion reactor, a tube filled with any one of the tritium breeding material, the neutron multiplier and the coolant is mounted in the blanket container, and a space between the tube and the blanket container is provided. A blanket for a fusion reactor, characterized by filling the remaining space with the remaining material. 2. A tritium breeding material for producing tritium, which is one of the fuels of a fusion reactor consumed by a fusion reaction in a plasma confined by a magnetic field, and a neutron multiplier for increasing tritium generation efficiency. A blanket container having a cooling structure for storing therein a doubler and a coolant that converts kinetic energy of neutrons generated in a nuclear fusion reaction into heat energy and takes out the heat is provided, and is installed in a region close to the plasma. In a fusion reactor blanket, a double tube filled with the tritium breeding material in the inner tube and the neutron multiplier in the outer tube is mounted in the blanket container, and the double tube and the double tube A blanket for a fusion reactor, wherein a space between the blanket container and the blanket container is filled with the coolant. 3. A tritium breeding material for producing tritium, which is one of the fuels of a fusion reactor consumed by a fusion reaction in a plasma confined by a magnetic field, and a neutron multiplier for increasing tritium generation efficiency. A blanket container having a cooling structure for storing therein a doubler and a coolant that converts kinetic energy of neutrons generated in a nuclear fusion reaction into heat energy and takes out the heat is provided, and is installed in a region close to the plasma. In a blanket of a nuclear fusion reactor, a double pipe having an inner pipe filled with the coolant and an outer pipe filled with the neutron multiplier is mounted in the blanket vessel, and the double pipe and the blanket A blanket for a nuclear fusion reactor, wherein a space between the tritium breeder and a space between the container and the container is filled with the tritium breeder. 4. The blanket of a fusion reactor according to claim 2 , wherein a spacer supporting the double tubes or the calandria tubes in the coolant gives a distribution to the flow of the coolant. A fusion reactor blanket, characterized by having: 5. A tritium breeding material for producing tritium, which is one of the fuels of a fusion reactor consumed by a fusion reaction in plasma confined by a magnetic field, and a neutron multiplier for increasing tritium generation efficiency. A blanket container having a cooling structure for storing therein a doubler and a coolant that converts kinetic energy of neutrons generated in a nuclear fusion reaction into heat energy and takes out the heat is provided, and is installed in a region close to the plasma. In a fusion reactor blanket, a tube filled with the coolant and a tube filled with the tritium breeding material are respectively mounted in the blanket container, and a neutron multiplier is provided in a space between each tube and the blanket container. A blanket for a fusion reactor characterized by being filled with doubled material. 6. The fusion reactor blanket according to claim 1 , wherein the tritium breeding material is a pebble or pellet of lithium or a lithium compound. Furnace blanket. 7. The blanket for a fusion reactor according to claim 6 , wherein said pebbles or pellets are pebbles or pellets having a controlled pore density. 8. The fusion reactor blanket according to any one of claims 1 to 7 , wherein the neutron multiplier is a pebble or pellet of beryllium and / or lead. Fusion reactor blanket. 9. The blanket of a fusion reactor according to claim 8 , wherein said pebbles or pellets are pebbles or pellets having a controlled pore density. 10. A fusion reactor comprising the blanket according to claim 1. Description: