RU2726940C1 - Thermonuclear reactor vacuum chamber - Google Patents

Abstract

FIELD: thermonuclear engineering.SUBSTANCE: invention relates to thermonuclear engineering and specifically to design of a vacuum chamber and a blanket, which are elements of a thermonuclear reactor or a demonstration thermonuclear neutron source (DEMO-TIN). Disclosed is a thermonuclear reactor vacuum chamber consisting of a housing formed by inner and outer shells, an intracavitary volume with metal structures and a circulating heat carrier, a circulation system consisting of heat carrier, heat exchanger and pump supply and discharge pipelines, wherein heat carrier used is a solution of lithium-containing material, or solution of minor actinides, or solution of raw material, circulation system includes branch pipe with branch pipes for bypass extraction of part of solution and supply of solution to circulation system installed before heat exchanger on pipeline of solution discharge.EFFECT: simplified design of DEMO-TIN and reduced neutron loss from plasma.5 cl, 4 dwg

Description

Technical field

The invention relates to thermonuclear technology, namely, to the designs of the vacuum chamber (VC) and blanket, which are elements of a thermonuclear reactor (TNR) or a demonstration thermonuclear neutron source (DEMO-TIN). It can be used in any installations where there is a need to transmute elements under the influence of a neutron flux.

State of the art

The vacuum chamber (VC) is one of the main systems of tokamak-type thermonuclear installations, in particular the DEMO-TIN installation.

Known VK design proposed in (EA Azizov et al. Tokamak DEMO-TIN: the concept of an electromagnetic system and a vacuum chamber. - VANT. Ser. Thermonuclear fusion, vol. 38, issue 2, 2015, p. 5).

VK consists of three elements - a body; internal volume with metal structures and water; internal volume.

1. The VK body is a steel toroidal structure with D-shaped vertical section pipes made of two coaxial shells - the inner one, facing the plasma, and the outer one, facing the cryostat.

2. The shells are interconnected by a system of toroidal and poloidal stiffeners.

The free space between the ribs and the shells is partially filled with metal radiation shielding plates.

The rest of the internal volume between the shells is filled with circulating water. Taken together, the internal metal structures and water form an iron-water radiation shield.

3. The inner shell of the housing limits the internal volume of the VC, which contains the first wall (SS), the divertor, the blanket and the discharge chamber, in which the thermonuclear reaction takes place.

This design is the closest to the claimed invention in terms of a set of essential features and is taken as a prototype.

The design of the VC and the functions of its elements are described in detail in (A.Yu. Pashkov et al. Transient processes in the vacuum chamber of the DEMO-TIN facility in case of accidents in its cooling system and in cooling systems for components facing the plasma. - VANT. Ser. Thermonuclear fusion , vol. 40, issue 3.2017, p. 78).

The water circulating between the VC shells performs two functions: firstly, it serves as a coolant - it removes the heat released as a result of interaction with neutrons and gamma quanta both in it and in the VC body and in-vessel radiation protection metal structures; secondly, it is radiation protection. High temperature water in the VC housing is also used to warm it up under certain operating modes.

The cooling and heating system of the VK body consists of several circuits. The inner circuit (cooling the body itself) consists of independent first and second inner circuits. Heat from the internal circuits is transferred through intermediate heat exchangers to the external circuit, which releases the heat to the environment. Internal circuits are equipped with relief valves that are triggered when the pressure in the circuits increases.

VK performs the following main functions:

- serves as a basis for fastening components facing the plasma (including the blanket), diagnostic and support systems;

- ensures maintenance of vacuum in the discharge chamber of the tokamak;

- creates a safety barrier in emergency situations;

- reduces the flux of neutrons and gamma-quanta on magnetic coils and ensures radiation sanitary standards in the tokamak building.

Blanket is one of the main systems of tokamak installations, where the main part of the neutron energy from the plasma is utilized. As a rule, the blanket consists of separate modules and is designed for isotope transmutation. Three types of transmutation are usually considered.

1. For the reproduction of tritium, which burns out in a thermonuclear reaction, modules are used, the design of which includes lithium-containing materials (LSM).

Known designs of a blanket, in which the LCM are in a solid state. (VV Kevrolev. Blanket of a thermonuclear reactor based on lithium oxide. - VANT. Ser. Thermonuclear fusion, issue 1, 1986, p. 37). It is proposed to use metallic lithium, eutectics of lithium and lead, a mixture of fluoride salts - flyb, ceramics Li ₄ SiO ₄ , Li ₂ SiO ₃ , LiAlO ₂ , LiO ₂ .

Known blanket designs, in which the modules contain aqueous solutions of lithium-containing salts (for example, LiOH, LiNO ₃ ) - ITER Concept definition, Vol. 2, p. 314, International Atomic Energy Agency, Vienna, 1989.

2. For the production of fissile fuel, modules are used, the design of which includes raw materials Th ²³² , U ²³⁸ . (E.P. Velikhov et al. Nuclear power system with fission and fusion reactors - a strategic landmark for the development of the industry - VANT. Ser. Thermonuclear fusion, vol. 40, issue 4, 2017, p. 5).

3. For transmutation of minor actinides (MA) - transuranic elements - and their conversion into short-lived fission products, modules containing MA are used. (AA Borisov. Possibilities of the ceramic blanket of the thermonuclear reactor DEMO-S for transmutation of neptunium in nitride fuel. VANT. Ser. Thermonuclear fusion, issue 4, 2004, p. 3).

The design of the blanket, consisting of separate modules located in the internal cavity of the VC, has certain disadvantages:

1. The use of separate modules requires devices to overload each of them.

2. The presence of many modules increases the proportion of structural materials (metal) in the blanket, and the metal is a parasitic absorber of neutrons.

3. For design reasons, blanket modules do not cover the entire inner surface of the VC (for example, they are absent in the area of the central solenoid, divertor).

4. Selection of the accumulated tritium i.e. its extraction from the TNR or TIN blanket is usually carried out in the following ways:

1) To extract tritium from the module, the module is removed from the installation and replaced with another, which requires a long downtime of the entire installation.

2) To separate tritium from the module, tritium carrier gas is pumped through the module. In this case, the shutdown of the TNR or TIN is not required, but the design of the blanket becomes more complicated, in addition, the blanket must be high-temperature. Periodic stops are also required to replace the LSM.

Disclosure of invention

The technical problem to be solved by the claimed invention is to simplify the design of the blanket and the entire DEMO-TIN installation and to reduce the loss of neutrons from the plasma.

The technical result of the claimed invention lies in the fact that the production of tritium or fissile isotopes or MA transmutation is performed inside the body of a blanket vacuum chamber (VKB) filled with a solution or solutions.

The technical result is achieved by the fact that a vacuum chamber of a thermonuclear reactor is proposed, consisting of a body formed by an inner and outer shell, an inner volume with metal structures and a circulating coolant, a circulation system consisting of pipelines for supplying and removing a coolant, a heat exchanger and a pump, while using a solution as a coolant lithium-containing material, or a solution of minor actinides, or a solution of raw material, the circulation system contains a branch with branch pipes for bypassing part of the solution and supplying the solution to the circulation system, installed in front of the heat exchanger 1 on the pipeline for removing the solution.

In a preferred embodiment:

- a layer of material that multiplies neutrons is applied to the inner shell of the housing, from the side facing the solution;

- at least one module of the inner blanket with solid minor actinides is installed in the internal volume of the body;

- between the inner and outer shells of the body there is a metal partition, dividing the inner volume into two independent chambers, each with its own solution and its own circulation system;

- the solution is made on the basis of heavy water.

Thus, the set of essential features of the proposed technical solution provides a simplification of the tokamak design and acceleration and simplification of the blanket loading / reloading process.

Further, two possible variants of the VKB design are considered - one-chamber (using only one type of solution) and two-chamber (using two types of solutions).

Brief Description of Drawings

FIG. 1 shows a general view of a single-chamber VKB installation DEMO-TIN, using only one type of solution. It is possible to use a solution of LSM, raw materials or MA. The numbers indicate:

1 - plasma;

2 - internal metal shell of VKB;

3 - external metal shell of VKB;

4 - solution;

5 - pipeline for supplying solution to VKB;

6 - pipeline for drainage of solution from VKB;

7 - by-pass selection of a part of the solution for the extraction of produced isotopes or fission products;

8 - layer of material - neutron breeder;

9 - module of the internal blanket containing MA;

10 - solution circulation pump;

11 - intermediate solution heat exchanger.

FIG. 2 shows a general view of a two-chamber VKB installation DEMO-TIN, using a combination of LSM solutions, raw materials and MA. The numbers indicate:

1 - plasma;

2 - internal metal shell of VKB;

3 - external metal shell of VKB;

4 - the first solution;

5 - pipeline for supplying (supplying) the first solution to the first chamber of the VKB;

6 - pipeline for withdrawing the first solution from the first chamber of the VKB;

7 - bypass withdrawal of a part of the first solution to extract fission products;

8 - layer of material - neutron breeder;

10 - circulation pump of the first solution;

11 - intermediate heat exchanger of the first solution;

12 - second solution;

13 - pipeline for supplying the second solution to the second chamber of the VKB;

14 - pipeline for withdrawing the second solution from the second chamber of the VKB;

15 - bypass selection of a part of the second solution to extract the produced isotopes;

16 - circulation pump of the second solution;

17 - intermediate heat exchanger of the second solution;

18 - an intermediate metal partition separating the first and second solution.

FIG. 3 shows a view of a single-chamber VKB (vertical section). The numbers indicate:

2 - internal metal shell of VKB;

3 - external metal shell of VKB;

4 - solution;

8 - layer of neutron breeder material;

12 - metal plates.

FIG. 4 shows a view of a single-chamber VKB (horizontal section). The numbers indicate:

2 - internal metal shell of VKB;

3 - external metal shell of VKB;

4 - solution;

8 - layer of material - neutron breeder;

12 - metal plates.

19 - insulating metal partitions between the compartments.

Implementation of the invention

VKB structurally consists of several elements - a body, an intra-body volume with metal structures and a solution (or two solutions), as well as an internal volume with components facing the plasma.

The essence of the claimed invention is that the internal volume of the VKB, not occupied by metal plates, is filled with either an LSM solution, or a solution of raw isotopes, or an MA solution, or a combination of these solutions). Solutions also perform the function of a heat carrier and radiation protection. Overloading of the blanket is carried out by bypass withdrawal of part of the solution for the separation of tritium, fissile isotopes or fission products from it.

The VKB body is a metal toroidal structure of a D-shaped vertical section of two coaxial shells - the inner one facing the plasma and the outer one facing the cryostat. The body material can be steel (as in the prototype), zirconium or vanadium alloys, which reduce parasitic absorption of neutrons.

The shells are interconnected by a system of toroidal and poloidal stiffeners. The free space between the shells is filled with a solution (or two solutions) and metal plates that form a radiation shield.

Some of the plates can be made of a neutron breeder material (for example, lead). Since the WKB surrounds the plasma from all sides, then practically all neutrons generated in the plasma will enter the solution (or solutions) and be used for isotopic transmutation. Only a slight leakage of neutrons through the VKB branch pipes, intended for fuel supply, diagnostics, plasma heating or repair work, is possible.

The body is divided into separate compartments, separated from each other by insulating metal partitions at 19 in FIG. 4. The number of insulating partitions is equal to the number of VKB sections. This is to prevent large fluid leakage. In the event of a leak from one compartment, the solution remains in the rest.

The VKB cooling system (Fig. 1 and 2) is a circulation loop, as in the prototype, but also includes a bypass system for the selection of tritium 7 and / or 15, located on the solution removal pipeline 6 and / or 14 in front of the heat exchanger 11 and / or 17 and feeding the solution back to the circulation system.

WKB consists of inner 2 and outer 3 metal shells, interconnected by a system of toroidal and poloidal stiffeners to give the structure strength. The free space between the shells is filled with a solution of 4 LSM and metal plates 12 Figs. 3, 4. Under the action of a neutron flux from plasma 1 in a solution of LSM 4, a reaction occurs

Li + n = T + He

The pump of the first or the only circulation loop 10 delivers the solution through the pipeline 5 into the internal volume of the VKB, where it is heated by the thermal energy released under the action of neutrons in the solution 4 itself, shells 2 and 3 and metal plates 12 of FIG. 3, 4 Then the solution is discharged through pipeline 6 to the intermediate heat exchanger 11, where it gives off heat to the water of the second cooling circuit.

From the solution in pipeline 6, discharged to the heat exchanger, a bypass part of it is taken through pipeline 7 to the tritium recovery system, and then the solution is returned to the first circulation loop.

It is possible to use in VKB an inner shell covered with a neutron breeder material. This neutron breeder layer is cooled by the circulating solution. This design will increase the amount of neutrons entering the solution.

It is possible to install blanket modules in the internal volume of the VKB containing fissile materials, in particular minor actinides (MA) in the solid aggregate state. Fission of MA by neutrons from plasma creates an additional amount of neutrons entering the solution.

The essence of the invention is illustrated in FIG. 1, 2 and 3, which show several variants of the VKB design.

1 The simplest single-chamber version. Figs. 1 and 3 of the VKB contains an inner shell 2, an outer shell 3, an LSM solution 4 for reproducing tritium between them, and metal plates 12.

2. Single-chamber version with a neutron breeder. (Figs. 1 and 3). VKB contains an inner shell 2, an outer shell 3, a solution 4 between them and metal plates 12, as well as a layer of a breeder 8 on an inner shell 2. The breeder is cooled with a solution 4.

3. Single chamber version with an internal blanket containing MA. (Figs. 1 and 3). The VKB contains an inner shell 2, an outer shell 3, a solution 4 between them and metal plates 12, as well as modules of the inner blanket with MA 9, located in the inner volume of the VKB and serving as an additional source of neutrons.

4. Single-chamber version with a neutron breeder and an internal blanket containing MA (Figs. 1 and 3). The VKB contains an inner shell 2, an outer shell 3 and a solution 4 between them, a breeder layer 8 on the inner shell 2 and modules of the inner blanket with MA 9 located in the inner volume of the VKB and performing the function of an additional source of neutrons. In the design under consideration, all neutrons from the inner blanket enter the solution.

5. The simplest two-chamber version (Fig. 2). VKB consists of two chambers filled with different solutions. The first chamber is bounded on one side by an internal metal shell VKB 2, and on the other by an intermediate metal partition 18. The volume between these partitions is filled with the first solution 4. The second chamber is limited on one side by an intermediate metal partition 18, and on the other by an external metal shell VKB 3. Volume between these partitions it is filled with the second solution 12. The following combination of solutions is possible:

1) First MA solution, second LSM.

2) First MA solution, second raw isotopes. The use of a two-chamber design gives the following

advantages:

- Fission of MA in the first chamber under the action of neutrons from the plasma serves as an additional source of neutrons for the second chamber, in which tritium or fissile isotopes are produced.

The two-chamber design makes it possible to simultaneously transmute MA and produce tritium or fissile isotopes.

6. Two-chamber version with a neutron breeder. (Figs. 2 and 3). The VKB consists of a first chamber bounded by an inner metal shell 2 and an intermediate metal partition 18. The volume between these partitions is filled with the first solution 4. The second chamber is bounded on one side by an intermediate metal partition 18, and on the other by an external metal shell VKB 3. The volume between these partitions filled with the second solution 12. On the side of the inner metal shell 2 facing the first solution, there is a layer of the breeder 8. The breeder is cooled with the first solution 4. The breeder can be placed on an intermediate metal partition 18. If it is in the first chamber, then the cooling is carried out with the first solution , and if in the second chamber, then with the second solution. It is possible to place the breeder on the intermediate metal partition 18 both in the first chamber and in the second one. It is possible to place the breeder both on the inner metal shell 2 and on the intermediate metal partition 18. The placement of the breeder layer on the outer metal shell 3 seems to be irrational.

The neutrons from the breeder (s) serve as an additional source of neutrons for the solutions of the first and second chambers.

The use of an internal blanket containing solid MA in a two-chamber design (Fig. 2, item 9) seems to be irrational and leads to a complication of the design.

7. Option with a solution of LSM in heavy water. Variants 1-6 are possible, in which LSM, MA and fissile isotopes are dissolved in heavy water, which practically does not absorb neutrons. This option gives the maximum reproduction rate of tritium or production of fissile isotopes.

Below is an example of a specific implementation of the device, which does not limit the options for its execution

Further consideration is carried out for a single-chamber VKB with an LCM solution intended for the production of tritium. Variants of using MA solution as a coolant for their transmutation into short-lived fission products, or a raw material solution for the production of fissile isotopes are also possible.

VKB consists (Fig. 1 and 3) of the inner 2 and outer 3 metal shells, interconnected by a system of toroidal and poloidal stiffeners to impart strength to the structure. The free space between the shells is filled with a solution of 4 LSM (for example, an aqueous solution of LiOH or LiNO ₃ ) and metal plates 12. Under the action of a neutron flux from plasma 1 in a solution of LSM 4, the reaction

Li + n = T + He

The pump of the first circulation loop 10 delivers the solution through the pipeline 5 into the internal volume of the VKB, where it is heated by the thermal energy released under the action of neutrons in the solution 4 itself, shells 2 and 3, and metal plates 12. Then the solution is discharged through pipeline 6 into the intermediate heat exchanger 11, where it gives off heat to the water in the second cooling circuit. To prevent the ingress of tritium into the environment, it is advisable to make the VKB cooling system three-circuit, and the water pressure in the second circuit is greater than the solution pressure in the first. To simplify the design, the solution has low parameters (temperature ~ 100 ° C and pressure ~ 1 MPa).

The in-house volume of the VKB is divided by insulating metal partitions (Fig. 4, pos. 9) into separate sections. If the solution leaks from one section, this will avoid the solution outflow from the entire internal volume of the VKB.

From the solution in the pipeline 6, discharged to the heat exchanger, a bypass part of it is taken through the pipeline 7 to the tritium recovery system, and then the solution is returned to the first circulation loop (not shown in the drawings). Breeder layer 8 on the surface of the inner shell of VKB 2, facing solution 4, increases the total number of neutrons entering solution 4.

In principle, there are two ways to overload the blanket chamber:

- When a certain concentration of produced isotopes (tritium, MA fission products or fissile isotopes) is reached in it, the solution is drained through the solution selection branch pipe and sent for processing. A new solution (LSM, MA, raw isotopes) with the initial concentration of isotopes to be transmuted is poured into the blanket, through the solution inlet pipe;

- The blanket is reloaded by bypassing part of the solution from the circulation loop to isolate tritium, MA fission products or fissile isotopes from it, then isotopes to be transmuted are added to the solution, and the solution is returned to the circulation loop. Stopping the TIN is not required in this case.

When installing an internal blanket with MA in its module 9, MA fission by neutrons from plasma 1 occurs with the formation of short-lived fission products. This process is also an additional source of neutrons entering the solution 4. Additional neutrons contribute to an increase in the tritium breeding coefficient in the WKB.

Metal plates 12 and solution 4 also perform the function of radiation protection, weakening the neutron flux from the plasma outside the WKB.

Thus, the claimed invention solves the following main problems, while retaining all the functions of the known VC design, it becomes possible to use it for isotope transmutation, i.e. give it a blanket function. For this, the water filling the VC is replaced with a solution of LSM, or raw materials or MA

This design has the following advantages:

- There is no need to install blanket modules with their own cooling system, fasteners, etc. in the internal volume of the VK. The design of the blanket is simplified;

- The system of blanket reloading is simplified. The selection of a part of the solution for the separation of tritium, fissile isotopes or fission products from it, as well as feeding the blanket with a fresh solution, can be performed continuously;

- The solution layer covers almost the entire surface of the VKB (except for the technological ports), i.e. practically all neutrons from the plasma enter the solution;

- The absence of a blanket located in the internal volume of the VK allows to increase the distance between the inner and outer shells of the VKB (to increase the thickness of the solution layer without increasing the dimensions of the outer shell of the VKB and thereby increase the protective properties of the VKB and reduce the radiation load on the superconducting coils). When using an LSM solution, the presence of tritium in the solution will not create an additional radiation load on the superconducting coils, because tritium decays to give soft beta radiation;

The proposed solution will simplify the design of the tokamak, increase the amount of produced tritium or fissile isotopes, or the amount of transmuted MA and will not adversely affect the safety of DEMO-TIN.

Claims (5)

1. The vacuum chamber of a thermonuclear reactor, consisting of a body formed by the inner 2 and outer 3 shells, an inner volume with metal structures and a circulating coolant, a circulation system consisting of pipelines for supplying 5 and 6 of the coolant, heat exchanger 11 and pump 10, characterized in that a solution of a lithium-containing material is used as a heat carrier, or a solution of minor actinides, or a solution of raw material, the circulation system contains an outlet with bypass pipes 7 of a part of the solution and supply of the solution to the circulation system, installed in front of the heat exchanger 11 on the pipe for removing the solution 6. 2. The vacuum chamber of a thermonuclear reactor according to claim 1, characterized in that a layer 8 of material that multiplies neutrons is applied to the inner shell 2 of the housing from the side facing the solution 4. 3. The vacuum chamber of a thermonuclear reactor according to claim 1, characterized in that at least one module of the inner blanket 9 with solid minor actinides is installed in the inner volume of the vessel. 4. The vacuum chamber of a thermonuclear reactor according to claim 1, characterized in that a metal partition 18 is located between the inner 2 and outer 3 shells of the body, dividing the inner volume into two independent chambers, each with its own solution and its own circulation system. 5. The vacuum chamber of the thermonuclear reactor according to claim 1, characterized in that the solution is made on the basis of heavy water.

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