A simulation method and device for an online regulation system of a tritium breeding rate of a liquid blanket of a fusion reactor

Abstract

The application discloses a fusion reactor liquid blanket tritium breeding rate online regulation system simulation method and device, wherein the simulation device comprises a fusion blanket neutron transport module, a blanket breeding agent Monte Carlo-activation coupling burnup simulation module, a blanket coolant feeding module, a blanket tritium extraction module, a blanket coolant purification treatment module, a blanket tritium breeding rate calculation module and a blanket tritium breeding agent circulation system; the simulation device realizes the circulation of the blanket coolant nuclide based on the mass conservation equation and the burnup equation. The application is based on the Boltzmann neutron transport equation, the neutron flux of the blanket coolant is simulated by a Monte Carlo method, the time and space variation law of the chemical composition of the system material is obtained by solving the burnup equation, the replenishment demand of the blanket coolant system is calculated, and the influence of the replenishment composition on the blanket tritium breeding rate is simulated, so that the application can be widely applied to the fusion reactor liquid lithium lead blanket.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fusion reactor engineering, and mainly relates to a simulation method and device for a fusion reactor liquid blanket tritium breeding ratio online regulation system. BACKGROUND

[0002] The tritium breeding blanket is the core component of the fusion reactor to achieve tritium self-sustaining, energy conversion and radiation shielding. Among them, the liquid blanket mostly uses liquid lithium lead as a tritium breeder and neutron multiplier, which can realize online tritium extraction and online regulation of tritium breeding ratio (TBR), and is considered to be an advanced blanket scheme for future fusion reactors.

[0003] At present, there are mainly three design schemes of liquid lithium lead blanket at home and abroad. The self-cooled liquid lithium lead blanket scheme is first proposed, which uses liquid lithium lead as a tritium breeder, neutron multiplier and coolant, and uses low-activation steel as a structural material. In order to achieve tritium self-sustaining, the blanket TBR is required to be greater than 1 in principle. However, due to the influence of factors such as engineering design, tritium burnup rate, tritium extraction efficiency, material circulation efficiency and the like, the blanket TBR needs to be as close to 1.15 as possible. Although the initial TBR of the fusion reactor liquid lithium lead blanket design reaches 1.20, as the fusion reactor operates, the tritium breeder and neutron multiplication material are subjected to neutron irradiation, resulting in burnup, and the content of the nuclide which contributes significantly to tritium production gradually decreases, and the TBR continuously decreases. Therefore, the blanket full-life equivalent TBR will be lower than the initial value, and may not be able to maintain the required tritium self-sustaining, especially when the breeding blanket is operated at high power, the TBR decreases more obviously. The blanket TBR is highly positively correlated with the Li element content, and the decrease of Li concentration caused by burnup has an important influence on TBR. The finer the division of geometric space has a significant influence on the calculation of TBR; the burnup of the breeding material causes the TBR to present a nonlinear decrease, and the greater the fusion power, the greater the amplitude of the nonlinear decrease of TBR; the change of lithium lead material composition and the change of neutron flux caused by the change of lithium lead material composition during the operation of the liquid lithium lead blanket are influenced by the spatial position of the material, irradiation time and fusion power coupling, and high-precision simulation of three-dimensional neutron flux and time-varying TBR coupling calculation are required to simulate the evolution of burnup and TBR. 6 6 Li concentration decrease has an important influence on TBR. The finer the division of geometric space has a significant influence on the calculation of TBR; the burnup of the breeding material causes the TBR to present a nonlinear decrease, and the greater the fusion power, the greater the amplitude of the nonlinear decrease of TBR; the change of lithium lead material composition and the change of neutron flux caused by the change of lithium lead material composition during the operation of the liquid lithium lead blanket are influenced by the spatial position of the material, irradiation time and fusion power coupling, and high-precision simulation of three-dimensional neutron flux and time-varying TBR coupling calculation are required to simulate the evolution of burnup and TBR.

[0004] The liquid lithium lead is used as a tritium breeder, neutron multiplier, coolant and carrier of tritium, and through flowing in the blanket system, tritium is produced through nuclear reaction and taken out of the reactor for online extraction. Therefore, by supplementing the tritium breeding and neutron multiplication material in the blanket coolant system, the lithium lead composition can be regulated online and the blanket TBR level can be maintained. Simulating the online regulation mechanism of the lithium lead blanket tritium breeding ratio can reveal the influence of factors such as the type of supplementing material, supplementing time, supplementing system flow, supplementing enrichment and activated product residual amount on the burnup degree of the tritium breeding material and the TBR, which has important engineering value for maintaining the TBR of the lithium lead blanket. ​SUMMARY

[0005] In order to calculate the burnup of the liquid lithium-lead blanket, the time-space evolution law of TBR with the running time of the fusion reactor, and simulate the physical process of the online regulation and control design of the tritium breeding rate, the application discloses a simulation method and device of a tritium breeding rate online regulation and control system of a fusion reactor liquid blanket.

[0006] The application is implemented by the following technical solutions:

[0007] A simulation method of a tritium breeding rate online regulation and control system of a fusion reactor liquid blanket, the method comprising the following steps:

[0008] 1) Establishing a three-dimensional Monte Carlo neutron model of the fusion reactor liquid blanket;

[0009] 2) Simulating and calculating the neutron flux in the liquid breeder and the initial tritium breeding rate of the blanket under the initial conditions;

[0010] 3) Under the conditions of a given irradiation scheme and time step, automatically generating a subdivided irradiation scheme for each stage, generating an activation calculation input file and performing activation calculation;

[0011] 4) Obtaining the material composition of the activated liquid breeder, modifying and updating the material composition of the breeder according to the purification efficiency and tritium extraction efficiency of the liquid breeder when the chemical and volume control system is chemically controlled;

[0012] 5) Modifying and updating the material composition of the liquid breeder in the Monte Carlo neutron model, simulating and calculating the neutron flux and the tritium breeding rate of the blanket after the change of the liquid breeder composition, repeating steps 3) to 4) until all irradiations are completed.

[0013] Further, in step 1), the Monte Carlo three-dimensional neutron model is established according to the liquid blanket design, the main component design scheme of the fusion reactor and the material composition of each component.

[0014] In step 2), the liquid breeder neutron flux is obtained by solving the Boltzmann equation to calculate the multi-group neutron energy spectrum of the liquid breeder in different regions through the Monte Carlo method.

[0015] Further, in step 3), the activation calculation input file is automatically generated using the fusion neutron analysis method.

[0016] Further, in step 3), the burnup equation is established and solved for the liquid breeder at different spatial positions to perform activation calculation.

[0017] Further, the liquid breeder is a liquid lithium-lead breeder.

[0018] The application also provides the following technical solutions.

[0019] A simulation device of an online regulating system of a tritium breeding rate of a liquid blanket of a fusion reactor, the simulation device comprising:

[0020] A liquid blanket, a heat exchanger, a stabilizer, a main pump, a chemical and volume control system, and a cooling pipeline;

[0021] The liquid blanket uses liquid metal as a tritium breeder;

[0022] The simulation device performs the simulation method as described above.

[0023] Further, in the simulation device, the irradiation area and the non-irradiation area are distinguished according to the irradiation degree; the liquid blanket is close to a neutron source of a fusion plasma, and is irradiated by a large number of high-energy neutrons during the operation of the fusion reactor, and belongs to the irradiation area; the heat exchanger, the stabilizer, the main pump, and the chemical and volume control system are far away from the neutron source and are protected by shielding, and the irradiation degree is very low, and they belong to the non-irradiation area.

[0024] Further, the simulation device simulates the irradiation activation, decay, and flow behavior of the liquid breeder during the operation of the liquid blanket: during the operation of the fusion reactor, the breeder is irradiated by neutrons in the irradiation area, and the breeder material is transmuted to produce radionuclides, and these radionuclides decay in the irradiation area and the non-irradiation area.

[0025] Further, the chemical control process of the chemical and volume control system includes gas radionuclide removal, tritium extraction, removal of activated products, and replenishment of the breeder.

[0026] Further, the simulation device simulates the evolution characteristics of the breeder material composition, the radioactivity, the tritium breeding rate, and the contact dose rate with the operation time of the fusion reactor.

[0027] In the simulation method of the online regulating system of the tritium breeding rate of the liquid blanket of the fusion reactor, the particle transport simulation is used to solve the Boltzmann equation to calculate the multi-group neutron energy spectrum of the liquid breeder in different spaces of the blanket, and the activation calculation file is generated by using the fusion neutron analysis software NATF.

[0028] In the method, the burnup equation is established and solved for the lithium-lead breeder at different spatial positions to perform activation calculation to obtain the total amount of activated products after irradiation for a given time step.

[0029] In the method, the material composition of each breeder area in the Monte Carlo neutron model is modified and updated using NATF, and the next round of Monte Carlo neutron transport calculation is performed to update the neutron flux and the activation calculation, until all irradiations are completed.

[0030] By the technical scheme, high-precision space-time discrete simulation of the liquid lithium-lead cladding is realized, and evolution characteristics of a breeding material composition with time and space, total breeding material burnup, and a TBR change rule with time are obtained.

[0031] The present application has the following advantages:

[0032] (1) The present application automatically completes the activation of the breeding agent in different regions of the three-dimensional space by the fusion neutron analysis method, thereby improving the activation calculation efficiency.

[0033] (2) The present application automatically updates the breeding agent material to generate an updated neutron model, thereby improving the Monte Carlo modeling efficiency.

[0034] (3) The present application supports automatic time step division for complex operation conditions such as discontinuous operation and variable power operation of the fusion reactor, and can efficiently realize the splitting of a given irradiation scheme.

[0035] (4) The present application can automatically search for the loading flow of a given TBR target and loading method, and can quickly give an online control scheme for maintaining the TBR level for a given irradiation scheme. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The present application is mainly a schematic diagram of the main components of the simulation device;

[0037] Figure 2 The present application is mainly a flowchart of the simulation method;

[0038] Figure 3 The present application is mainly a schematic diagram of the main functional modules. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0040] The present application discloses a fusion reactor liquid blanket tritium breeding rate online control system simulation method and device. By establishing a fusion reactor liquid blanket main cooling system and a chemical and volume control system model, the evolution characteristics of the breeding material composition, radioactivity, tritium breeding rate and contact dose rate with the fusion reactor operation time are simulated.

[0041] According to the simulation device of the present application, the fusion reactor liquid blanket main cooling system and the chemical and volume control system are simplified to only include the main components and the chemical and volume control system, such as Figure 1The simplified model includes the components of liquid blanket, heat exchanger, pressurizer, main pump, chemical and volume control system and cooling pipe. The liquid lithium lead is used as tritium breeder and neutron multiplier, and also as the carrier of coolant and tritium. The lithium lead is irradiated by high-energy neutrons when it flows through the irradiation zone, i.e. the blanket region, and produces tritium through nuclear reactions. When the breeder flows to the non-irradiation zone, part of the lithium lead is led by the chemical and volume control system for online extraction of tritium. The chemical and volume control system also undertakes the functions of purifying the breeder and supplementing the breeder. The breeder with changed composition flows back to the irradiation zone, causing changes in neutron flux and tritium breeding rate, and further causing changes in the coupling of burnup.

[0042] Figure 2 The method of the present application is used to simulate the changes in breeder burnup and tritium breeding rate with high precision in space and time. The method first establishes a Monte Carlo three-dimensional neutron model according to the design of the liquid lithium lead blanket, the design scheme of the main components of the fusion reactor and the material composition of each component, and simulates the neutron flux in the liquid lithium lead breeder and the initial tritium breeding rate of the blanket under the initial conditions. Then, under the condition of a given irradiation scheme, the product of the irradiation power and the full-power irradiation time at each stage is calculated to obtain the effective full-power time, and the total effective full-power time is accumulated. The step size used when subdividing the irradiation scheme is the effective full-power year (EFPY), which is the product of the power and the full-power time (megawatt-year). The irradiation time (year) of each subdivided irradiation scheme is calculated by dividing the step size by the irradiation power (megawatt) at each stage, realizing the automatic generation of the subdivided irradiation scheme at each stage. For example, if the irradiation scheme is 200 megawatts for 1 full-power year, and then 500 megawatts for 2 full-power years, the step size is 20 megawatt-years. Then the irradiation scheme will be automatically subdivided into 200 megawatts for 0.1 year for 10 times, and 500 megawatts for 0.04 year for 50 times, and the composition of the liquid breeder material will be updated after each irradiation during the calculation. The activation calculation input file is automatically generated using the fusion neutron analysis program, and the activation calculation is performed. Then the material composition of the tritium breeder after activation is obtained, and the updated tritium breeder material composition is calculated according to the purification efficiency of different nuclides, the tritium extraction efficiency and the replenishment composition and capacity at different times when the chemical and volume control system is chemically controlled. The iteration of the neutron transport, activation calculation and material updating process is performed until the irradiation scheme is completed, and the tritium breeding rate and the change in the composition of the breeding material at different times during the iteration process are calculated.

[0043] Figure 3The main function module of the method of the present application is shown. The present application realizes the function of high-precision time and space discrete burnup simulation by coupling time step and space division function through the transport-activation coupled burnup calculation module. The simulation calculation of the influence of irradiation scheme on burnup is realized through automatic subdivision and scanning calculation of the irradiation scheme. On this basis, the simulation calculation of the influence of a given tritium breeder replenishment scheme is realized through forward scanning calculation of the replenishment type, replenishment time, replenishment enrichment and replenishment flow rate of the tritium breeder.

[0044] The part of the present application not described in detail belongs to the known technology in the art.

[0045] Although the above describes the specific embodiments of the present application in a descriptive manner, so as to facilitate the understanding of the present application by the person skilled in the art. But it should be clear that the present application is not limited to the scope of the specific embodiments, and for the person skilled in the art, as long as various changes are within the scope of the appended claims and the determined spirit and scope of the present application, these changes are obvious, and are within the protection of the present application.

Claims

1. A method for simulating an online control system for tritium breeding rate in a fusion reactor liquid blanket, characterized by: The method comprises the following steps: 1) Establish a Monte Carlo neutronics model of a three-dimensional fusion reactor liquid blanket; 2) Simulate and calculate the neutron flux of the liquid breeder and the initial tritium breeding rate of the blanket under initial conditions; 3) Under the given irradiation scheme and time step conditions, the system automatically generates subdivided irradiation schemes for each stage, generates activation calculation input files and performs activation calculations; 4) Obtain the material composition of the activated liquid breeder agent, and modify and update the material composition of the liquid breeder agent based on the purification efficiency and tritium extraction efficiency of the liquid breeder agent during chemical control by the chemical and volume control system; 5) Modify and update the material composition of the liquid breeder in the Monte Carlo neutronics model, simulate and calculate the neutron flux and blanket tritium breeding rate after the liquid breeder composition changes, and repeat steps 3) to 4) until all irradiations are completed; In step 1), the Monte Carlo three-dimensional neutronics model is established based on the liquid blanket design, the design scheme of the main components of the fusion reactor and the material composition of each component; In step 2), the neutron flux of the liquid breeder is obtained by solving the Boltzmann equation using the Monte Carlo method to calculate the multi-group neutron energy spectrum in different regions of the liquid blanket; In step 3), the activation calculation input file is automatically generated using the fusion neutronics analysis method; In step 3), for the liquid proliferation agent at different spatial positions, the fuel consumption equation is established and solved to perform activation calculation.

2. The method for simulating an online control system for tritium breeding rate in a fusion reactor liquid blanket according to claim 1, characterized in that: The liquid proliferation agent is a liquid lithium-lead proliferation agent.

3. A fusion reactor liquid blanket tritium breeding rate online control system simulation device, characterized in that: The simulation device comprises: Liquid blanket, heat exchanger, pressurizer, main pump, chemical and volume control system and cooling piping; The liquid blanket uses liquid metal as a liquid breeder of tritium; The simulation device executes the simulation method according to any one of claims 1 to 2.

4. The fusion reactor liquid blanket tritium breeding rate online control system simulation device according to claim 3, characterized in that: In the simulation device, irradiated areas and non-irradiated areas are distinguished according to the degree of irradiation. Among them, the liquid blanket is close to the fusion plasma neutron source and is irradiated by a large amount of high-energy neutrons when the fusion reactor is in operation, and belongs to the irradiated area; the heat exchanger, pressurizer, main pump and chemical and volume control system are far from the neutron source and are shielded and protected, and the degree of irradiation is very low, and belong to the non-irradiated area.

5. The fusion reactor liquid blanket tritium breeding rate online control system simulation device according to claim 4, characterized in that: The simulation device simulates the irradiation activation, decay and flow behavior of the liquid breeder in the liquid blanket during operation: when the fusion reactor is in operation, the breeder is irradiated by neutrons in the irradiation zone, the bred material transmutes to produce radioactive nuclides, and these radioactive nuclides decay in the irradiation zone and the non-irradiation zone.

6. The fusion reactor liquid blanket tritium breeding rate online control system simulation device according to claim 5, characterized in that: The chemical control process of the chemical and volume control system includes gas nuclide removal, tritium extraction, activation product removal, and proliferation agent supplementation.

7. The fusion reactor liquid blanket tritium breeding rate online control system simulation device according to claim 6, characterized in that: The simulation device simulates the evolution characteristics of the breeder material composition, radioactivity, tritium breeding rate and exposure dose rate over the operation time of the fusion reactor.

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