Design method of four-proton beam current ads device

Abstract

The application relates to a design method of a four-proton beam flow ADS device, which comprises the following steps: establishing a reactor model, wherein the reactor model comprises a shielding layer, a reflecting layer, a fuel area and a heavy metal target; the heavy metal target comprises a central heavy metal target and three surrounding heavy metal targets; arranging accelerators for the heavy metal target, wherein the accelerators are provided in two, and are respectively a first accelerator for bombarding the central heavy metal target and a second accelerator for alternately bombarding the three surrounding heavy metal targets, so as to generate a four-proton beam flow; establishing an external source disturbance point reactor neutron dynamics equation; obtaining dynamic parameters in the reactor model based on the reactor model and the accelerators; determining a power upper limit of the reactor model based on temperature limits of each structure in the reactor model; the temperature limit of each structure is a temperature corresponding to a melting point of a material of each structure; and if the reactor power exceeds the power upper limit, adjusting structure parameters of the reactor model and operation parameters of the accelerators.

Description

Technical Field

[0001] This invention relates to the field of accelerator-driven subcritical nuclear reactor (ADS) systems, and more particularly to a design method for a four-proton beam ADS device. Background Technology

[0002] An ADS (Alternating Current Distribution) device consists of an accelerator, a spallation target, and a subcritical reactor. Charged particles (such as protons and tritium ions) accelerated by the accelerator bombard the heavy metal spallation target placed inside the reactor, generating a spallation neutron source to maintain the operation of the subcritical reactor. The ADS concept was first proposed by Nobel laureate in physics Caro Rubbia, and since then, there has been considerable research both domestically and internationally. In the 1990s, the US ATW project proposed an ADS design with a thermal power of approximately 100 MW, using a tungsten target as the spallation target and 1 GeV protons as the incident particles, theoretically capable of transmuting over 200 kg of nuclear waste annually. Russia's IPPE Institute designed a lead-bismuth cooled ADS system, and the EU's EFIT project designed a 600 MeV proton accelerator-driven subcritical reactor, focusing on fuel cycle economics and safety. In addition, Belgium launched the MRRHA (Myrrahha linear accelerator) project, Italy launched the TRASCO project, France launched the GEDEON project, and Switzerland launched the MEGAPE project.

[0003] Because the neutron spectrum in the fuel region of an ADS device is hard, the minor actinides in the spent fuel have a high fission capture ratio, and the neutron consumption of the subcritical reactor chain reaction is less than that of a subcritical reactor. Therefore, the ADS device has better neutron economy and is conducive to the transmutation of spent fuel. Conducting research on ADS devices is of great significance for solving the problems of nuclear fuel supply and nuclear waste disposal, thereby promoting the sustainable development of nuclear energy and ensuring energy security.

[0004] Most existing ADS device designs focus on single-proton beams. However, the engineering applications of ADS devices require high beam power. For single-beam schemes, how to ensure reliability and stability while maintaining high beam power has become one of the key problems to be solved. Multi-proton beam schemes can effectively solve this technical problem. Currently, the concepts of three-beam (JU KNEBEL et al., Design and Corrosion Study of a Closed Spallation TargetModule of an Accelerator-driven System (ADS), Nucl. Eng. Des., 202, 279 (2000)) and seven-beam (S. ASSADI et al., 800 MeV>10 MW Proton Driver for ADSFission, Trans. Am. Nucl. Soc., 105, 11 (2011)) have been proposed, but no specific device layout and external source design for ADS devices have been seen, nor have any specific implementation schemes for multi-beam external sources been found. Therefore, there is an urgent need to provide a design method for multi-proton beam ADS devices to provide a reference for the engineering design of multi-beam ADS. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a design method for a four-proton beam ADS device.

[0006] To achieve the above-mentioned objectives, this invention provides a design method for a four-proton beam ADS device, comprising the following steps:

[0007] S1. Establish a reactor model, wherein the reactor model includes a shielding layer, a reflector layer, a fuel zone, and a heavy metal target; the heavy metal target includes: a central heavy metal target and three surrounding heavy metal targets;

[0008] S2. An accelerator is arranged for the heavy metal target, wherein there are two accelerators, namely a first accelerator for bombarding the central heavy metal target and a second accelerator for bombarding the three surrounding heavy metal targets in turn, so as to generate a four-proton beam.

[0009] S3. Establish the neutron dynamics equations for an externally perturbed point reactor; wherein, dynamic parameters in the reactor model are obtained based on the reactor model and the accelerator;

[0010] S4. Determine the upper power limit of the reactor model based on the temperature limits of each structure in the reactor model; wherein, the temperature limit of each structure is based on the temperature corresponding to the melting point of the material of each structure.

[0011] S5. If the reactor power exceeds the power limit, adjust the structural parameters of the reactor model and the operating parameters of the accelerator.

[0012] According to one aspect of the invention, in the reactor model, the three surrounding heavy metal targets are uniformly distributed on a circumference centered on the central heavy metal target.

[0013] According to one aspect of the invention, in the reactor model, the reflective layer covers the outside of the fuel zone, and the shielding layer covers the outside of the reflective layer;

[0014] The reflective layer includes: an axial reflective layer portion and a radial reflective layer portion;

[0015] The axial reflective layer is respectively provided at both ends of the axial direction of the fuel zone;

[0016] The shielding layer includes: an axial shielding layer portion and a radial shielding layer portion;

[0017] The axial shielding layer portion is disposed on the outside of the axial reflective layer portion;

[0018] The axial shielding layer is provided with a first channel through which the heavy metal target passes;

[0019] The axial reflective layer is provided with a second channel through which the heavy metal target passes;

[0020] The fuel zone is provided with a third channel for the insertion of the heavy metal target;

[0021] The central heavy metal target is positioned at the center of the fuel zone.

[0022] According to one aspect of the invention, the thickness of the axial reflective layer portion is greater than the thickness of the axial shielding layer portion;

[0023] The thickness of the radial reflective layer portion is greater than the thickness of the radial shielding layer portion;

[0024] The axial shielding layer is made of 57% LBE material and 43% T91 steel.

[0025] The axial reflective layer is made of 57% LBE material and 43% T91 steel.

[0026] The radial shielding layer is made of 9.4% LBE material, 10.6% T91 steel and 80% boron carbide.

[0027] The radial reflective layer is made of 93.1% LBE material and 6.9% T91 steel.

[0028] According to one aspect of the invention, the fuel zone includes a fuel portion, a coolant, a support structure, and pore gaps;

[0029] In the fuel zone, the fuel portion accounts for 24.33%, the coolant portion accounts for 57%, the support structure portion accounts for 16.67%, and the pore gap portion accounts for 2%.

[0030] The coolant is made of a lead-bismuth alloy;

[0031] The supporting structure is made of T91 steel;

[0032] The composition of the fuel portion is determined according to the pressurized water reactor unloading ratio, and the ratio of minor actinides to plutonium is 1.1 / 8.9. The fuel portion includes: 35.35% lead, 28.92% bismuth, 12.76% iron, 14.24% zirconium, 3.30% plutonium, 2.14% americium, and 3.29% filler.

[0033] The filler is at least one of chromium, tungsten, manganese, vanadium, carbon, silicon, tantalum, neptunium, and curium.

[0034] According to one aspect of the invention, the fuel portion is provided with 2% pore gaps, and the pore gaps are uniformly distributed in the fuel portion.

[0035] According to one aspect of the invention, the heavy metal target is made of 55.00% lead and 45.00% bismuth.

[0036] According to one aspect of the present invention, in step S2, in the step of arranging the accelerator for the heavy metal target, the accelerator adopts a continuous beam operation mode or a pulse beam operation mode, wherein when the continuous beam operation mode is adopted, both the first accelerator and the second accelerator adopt continuous beam high-energy proton accelerators, and when the pulse beam operation mode is adopted, both the first accelerator and the second accelerator adopt pulse beam high-energy proton accelerators.

[0037] In the continuous beam operation mode, the first accelerator bombards the central heavy metal target at a first flux intensity, and the second accelerator bombards the three surrounding heavy metal targets alternately at a second flux intensity and a first rotation speed; wherein, the first flux intensity of the first accelerator is set such that the material temperature rise caused by energy deposition from the spallation reaction of the central heavy metal target is within a safe limit; wherein, the safe limit is set based on the temperature corresponding to the melting point of the material of the central heavy metal target.

[0038] The second current intensity and the first rotational speed of the second accelerator are set such that the material temperature rise caused by energy deposition from the spallation reaction of each surrounding heavy metal target is within a safe limit; wherein the safe limit is set based on the temperature corresponding to the melting point of the material of the surrounding heavy metal target.

[0039] For the pulse beam operation mode, the first accelerator bombards the central heavy metal target at a first fixed frequency, and the second accelerator bombards the three surrounding heavy metal targets in turn at a second fixed frequency and a second rotation speed; wherein, the first fixed frequency of the first accelerator is set so that the material temperature rise caused by the energy deposition of the central heavy metal target due to the spallation reaction is within a safe limit; wherein, the safe limit is set based on the temperature corresponding to the melting point of the material of each structure in the reactor model.

[0040] The second fixed frequency and the second rotational speed of the second accelerator are set such that the material temperature rise caused by energy deposition from the spallation reaction of each surrounding heavy metal target is within a safe limit; wherein the safe limit is based on the temperature setting corresponding to the material melting point of each structure in the reactor model.

[0041] According to one aspect of the present invention, in step S3, the step of establishing the neutron dynamics equations of the externally perturbed point pile is expressed as follows:

[0042]

[0043] in, n ( t The neutron density () represents the number of neutrons per unit volume, which changes with time. t change;

[0044] C i ( t ) indicates the first i The density of slow-emitting neutron precursor nuclei over time t change;

[0045] ρ ( t ) indicates reactivity, and When the reactivity value is 1, the rate of neutron production in the reactor is equal to the rate of neutron disappearance.

[0046] k eff It represents the effective neutron multiplication factor, which is the ratio of the production rate to the disappearance rate of all neutrons in the reactor core;

[0047] β This represents the total delayed neutron share, which is equal to the sum of the delayed neutron shares of all groups, i.e.; ;

[0048] β i Indicates the first i The proportion of slow-emission neutrons in the group;

[0049] Λ Indicates neutron generation time;

[0050] λ i Indicates the first i The decay constant of the slow-emitting neutron precursor nucleus;

[0051] I This indicates the number of delayed neutron groups, usually taken as... I =6, used to correspond to six groups of delayed neutrons;

[0052] This represents an external neutron source, where, for continuous beam operation mode, A constant value is adopted; for pulsed beam operation mode, based on the beam characteristics generated by the pulsed beam high-energy proton accelerator and the mechanism by which protons interact with the heavy metal target to produce neutrons. Modeled as a Gaussian impulse, that is: ,in, The amplitude of the pulse. The standard deviation of the Gaussian pulse. The pulse number. The time interval between adjacent pulses;

[0053] In step S3, the step of obtaining the dynamic parameters in the reactor model based on the reactor model and the accelerator includes the following dynamic parameters: total delayed neutron fraction. β , No. i The share of slow-emission neutrons β i Neutron generation time Λ、 No. i decay constant of slow-emitting neutron precursor nuclei λ i .

[0054] According to one aspect of the present invention, in step S5, the step of adjusting the structural parameters of the reactor model is used to adjust the center distance between the surrounding heavy metal target and the central heavy metal target.

[0055] In step S5, the step of adjusting the operating parameters of the accelerator includes, for continuous beam operation mode, adjusting the first current intensity of the first accelerator and adjusting the second current intensity and first rotation speed of the second accelerator.

[0056] For the pulse beam operation mode, adjust the first fixed frequency of the first accelerator, and adjust the second fixed frequency and second rotation speed of the second accelerator.

[0057] According to one aspect of the present invention, the present invention can significantly reduce the energy and flux requirements of a single accelerator, thereby reducing the technical implementation difficulty and cost of the accelerator, extending the core life, and enhancing the safety and stability of the ADS device operation.

[0058] According to one aspect of the present invention, the present invention has a good balance in meeting the requirements of beam quantity and reactor power, which helps to improve the safety and stability of the ADS device, and at the same time expands the development space for the design and application of multi-proton beam ADS devices.

[0059] According to one aspect of the present invention, by setting up four proton beams, the energy and flux requirements of a single accelerator can be reduced, thereby lowering the technical implementation difficulty and cost of the accelerator. Compared to the traditional single-beam scheme, which suffers from high heat load on the reactor core and is prone to damage due to local overheating, the multi-beam scheme proposed in this invention can significantly extend the reactor core's lifespan by dispersing the heat load. Simultaneously, this scheme also reduces the problem of local overheating in the reactor core, thus more effectively improving the safety and stability of the reactor core. Furthermore, the multi-beam drive mode designed in this invention can reduce the space charge effect during high-energy proton transport, effectively avoiding the drawbacks of increased beam emittance and beam loss caused by the space charge effect.

[0060] According to one aspect of the present invention, the present invention creatively adopts a dual-accelerator design, which can fully improve the utilization rate of the accelerator and can flexibly control the rotation speed of the accelerator to effectively avoid the problem of excessive energy deposition and excessive temperature caused by long-term bombardment of heavy metal targets, thus more effectively improving the safety of the designed ADS device.

[0061] According to one aspect of the present invention, the present invention creatively applies the more mature pulse beam high-energy proton accelerator to ADS, which can reduce the technical difficulty of accelerator development, and can meet the power requirements of the reactor by controlling the frequency and rotation speed. Attached Figure Description

[0062] Figure 1 A step diagram illustrating the design method of a four-proton beam ADS device according to one embodiment of the present invention;

[0063] Figure 2 A flowchart illustrating the design method of a four-proton beam ADS device according to one embodiment of the present invention;

[0064] Figure 3 This is a structural diagram of a four-proton beam ADS device according to one embodiment of the present invention;

[0065] Figure 4This is a diagram showing the arrangement of a heavy metal target in a four-proton beam ADS device according to one embodiment of the present invention.

[0066] Figure 5 This is a diagram showing the relative positions of the shielding layer, reflective layer, fuel region, and heavy metal target of a four-proton beam ADS device according to one embodiment of the present invention.

[0067] Figure 6 Effective multiplication factor in a four-proton beam ADS device according to one embodiment of the present invention k eff A graph showing the relationship between the circumference of the surrounding heavy metal targets and the circumference of the circles arranged in a circular pattern.

[0068] Figure 7 This is a graph showing the relationship between the fission rate of minor actinide (MA) nuclides and the circumferential radius of the surrounding heavy metal targets arranged in a circular pattern in a four-proton beam ADS device according to one embodiment of the present invention.

[0069] Figure 8 This is a reactor power diagram summarizing the first and second accelerators at different accelerator frequencies, according to one embodiment of the present invention. Detailed Implementation

[0070] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0071] In describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" express orientations or positional relationships based on the orientations or positional relationships shown in the relevant drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on the present invention.

[0072] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail here, but the embodiments of the present invention are not limited to the following embodiments.

[0073] Combination Figure 1 , Figure 2 and Figure 3 As shown, according to one embodiment of the present invention, a design method for a four-proton beam ADS device includes the following steps:

[0074] S1. Establish a reactor model, wherein the reactor model includes a shielding layer 1, a reflector layer 2, a fuel zone 3, and a heavy metal target 4; the heavy metal target 4 includes: a central heavy metal target 41 and three surrounding heavy metal targets 42;

[0075] S2. An accelerator 5 is arranged for the heavy metal target. There are two accelerators 5, namely a first accelerator 5a for bombarding the central heavy metal target and a second accelerator 5b for bombarding the three surrounding heavy metal targets in turn, so as to generate a four-proton beam.

[0076] S3. Establish the neutron dynamics equations for the externally perturbed point reactor; wherein, dynamic parameters in the reactor model are obtained based on the reactor model and accelerator 5;

[0077] S4. Determine the upper limit of the reactor model's power based on the temperature limits of each structure in the reactor model; wherein, the temperature limit of each structure is based on the temperature corresponding to the melting point of the material of each structure.

[0078] S5. If the reactor power exceeds the power limit, adjust the structural parameters of the reactor model and the operating parameters of accelerator 5.

[0079] like Figure 3 As shown, according to one embodiment of the present invention, in step S1, the step of establishing the reactor model, the reflective layer 2 covers the outside of the fuel zone 3, and the shielding layer 1 covers the outside of the reflective layer 2; specifically, the reflective layer 2 includes: an axial reflective layer portion 21 and a radial reflective layer portion 22; wherein, the axial reflective layer portion 21 is respectively disposed at both ends of the axial direction of the fuel zone 3; while the radial reflective layer portion 22 covers the outside of the fuel zone 3 circumferentially; further, the shielding layer 1 includes: an axial shielding layer portion 11 and a radial shielding layer portion 12; wherein, the axial shielding layer portion 11 is disposed outside the axial reflective layer portion 21; while the radial shielding layer portion 12 covers the outside of the radial reflective layer portion 22 circumferentially.

[0080] In this embodiment, the axial shielding layer portion 11 is provided with a first channel 111 through which the heavy metal target 4 passes; the axial reflective layer portion 21 is provided with a second channel 211 through which the heavy metal target 4 passes; and the fuel zone 3 is provided with a third channel 31 for the insertion of the heavy metal target 4. Thus, the first channel 111, the second channel 211 and the third channel 31 are coaxially connected in sequence, which facilitates the insertion and installation of the heavy metal target 4.

[0081] In this embodiment, in the reactor model, three peripheral heavy metal targets 42 are evenly distributed on a circumference centered on the central heavy metal target 41. Thus, the arrangement of the first channel 111 on the axial shielding layer 11, the second channel 211 on the axial reflective layer 21, and the third channel 31 on the fuel zone 3 matches the installation position of each heavy metal target 4, achieving the corresponding installation. The central heavy metal target 41 is positioned at the center of the fuel zone 3. Therefore, the three peripheral heavy metal targets 42 are accurately distributed along the circumference by considering the position of the central heavy metal target 41 and the center-to-center distance between the peripheral heavy metal targets 42 and the central heavy metal target 41.

[0082] like Figure 3 As shown, according to one embodiment of the present invention, the thickness of the axial reflective layer portion 21 is greater than the thickness of the axial shielding layer portion 11; the thickness of the radial reflective layer portion 22 is greater than the thickness of the radial shielding layer portion 12. In this embodiment, the axial reflective layer portion 21 is made of 57% LBE material (i.e., liquid lead-bismuth alloy) and 43% T91 steel; the axial shielding layer portion 11 is made of 57% LBE material (i.e., liquid lead-bismuth alloy) and 43% T91 steel; furthermore, the radial shielding layer portion 12 is made of 9.4% LBE material, 10.6% T91 steel, and 80% boron carbide; the radial reflective layer portion 22 is made of 93.1% LBE material and 6.9% T91 steel.

[0083] like Figure 3 As shown, according to one embodiment of the present invention, the fuel zone 3 includes a fuel portion, a coolant, a support structure, and pore gaps. Specifically, in the fuel zone 3, the fuel portion accounts for 24.33%, the coolant accounts for 57%, the support structure accounts for 16.67%, and the pore gaps account for 2%; wherein, the coolant is made of lead-bismuth alloy; and the support structure is made of T91 steel. The function of the support structure is to ensure the stability of the entire structure of the fuel zone 3, and its structural design is a common design and will not be described in detail here. In this embodiment, the 2% pore gaps in the fuel zone 3 are arranged in a uniform distribution.

[0084] Furthermore, the composition of the fuel portion is determined with reference to the pressurized water reactor unloading ratio, and the ratio of minor actinides (MA) to plutonium (Pu) is 1.1 / 8.9. The fuel portion includes: 35.35% lead, 28.92% bismuth, 12.76% iron, 14.24% zirconium, 3.30% plutonium, 2.14% americium, and 3.29% filler. The filler is at least one of chromium, tungsten, manganese, vanadium, carbon, silicon, tantalum, neptunium, and curium.

[0085] In this embodiment, the fuel portion has 2% porosity gaps, and the porosity gaps are evenly distributed in the fuel portion, that is, 2% of the area in the fuel portion is porosity gaps.

[0086] like Figure 3 As shown, according to one embodiment of the present invention, the initial center distance between the surrounding heavy metal target 42 and the central heavy metal target 41 is determined based on the comprehensive total power and the transmutation performance of nuclear waste. Specifically, the comprehensive total power can be determined based on the design of the four-proton beam ADS device, and based on the aforementioned determination of the composition of fuel zone 3, a physical model of the interaction between the proton beam and the spallation target can be constructed according to the reactor spallation target model. The Monte Carlo simulation program is used to perform high-energy proton target transport calculations, the low-energy cross-section data is obtained using the ENDF / B-VII.1 nuclear database, and the high-energy cross-section data is calculated using the intranuclear cascade model (INC) and the pre-equilibrium model. The fission-capture ratio of MA and Pu is obtained from the fission macro-section and the capture macro-section. The larger the ratio, the stronger the transmutation ability. The center distance is adjusted to optimize the transmutation ability to determine the initial center distance. Furthermore, the external intensity provided by the heavy metal target 4 is based on the proton energy spectrum of the accelerator. Specifically, according to the proton energy spectrum of the selected accelerator and based on the reactor spallation target modeling, a physical model of the interaction between the proton beam and the spallation target is constructed. A Monte Carlo simulation program is used to perform high-energy proton target transport calculations, thereby obtaining the spallation neutron source intensity generated by proton bombardment of the heavy metal target 4 (i.e., the external intensity provided by the heavy metal target 4). In this embodiment, the heavy metal target 4 is made of 55.00% lead and 45.00% bismuth.

[0087] like Figure 3As shown, according to one embodiment of the present invention, in step S2, in the step of arranging accelerators for the heavy metal target 4, the accelerator 5 adopts either a continuous beam operation mode or a pulsed beam operation mode. When the continuous beam operation mode is adopted, both the first accelerator 5a and the second accelerator 5b are continuous beam high-energy proton accelerators; when the pulsed beam operation mode is adopted, both the first accelerator 5a and the second accelerator 5b are pulsed beam high-energy proton accelerators. In this embodiment, for the continuous beam operation mode, the first accelerator 5a bombards the central heavy metal target 41 at a first flux intensity, and the second accelerator 5b bombards the three surrounding heavy metal targets 42 alternately at a second flux intensity and a first rotation speed. In this embodiment, the first current intensity of the first accelerator 5a is set such that the material temperature rise caused by energy deposition from the spallation reaction of the central heavy metal target 41 is within a safe limit; wherein, the safe limit is set based on the temperature corresponding to the material melting point of each structure in the reactor model (such as the support structure made of T91 steel); the second current intensity and the first rotation speed of the second accelerator 5b are set such that the material temperature rise caused by energy deposition from the spallation reaction of each surrounding heavy metal target 42 is within a safe limit; wherein, the safe limit is set based on the temperature corresponding to the material melting point of each structure in the reactor model (such as the support structure made of T91 steel).

[0088] In the pulse beam operation mode, the first accelerator 5a bombards the central heavy metal target 41 at a first fixed frequency, and the second accelerator 5b bombards the three surrounding heavy metal targets 42 in turn at a second fixed frequency and a second rotation speed. In this embodiment, the first fixed frequency of the first accelerator 5a is set such that the material temperature rise caused by energy deposition from the spallation reaction of the central heavy metal target 41 is within a safe limit. The safe limit is based on the temperature corresponding to the melting point of the material of each structure in the reactor model (such as the support structure made of T91 steel). The second fixed frequency and second rotation speed of the second accelerator 5b are set such that the material temperature rise caused by energy deposition from the spallation reaction of each surrounding heavy metal target 42 is within a safe limit. The safe limit is based on the temperature corresponding to the melting point of the material of each structure in the reactor model (such as the support structure made of T91 steel).

[0089] According to one embodiment of the present invention, in step S3, the step of establishing the neutron dynamics equations of the externally perturbed point pile is expressed as follows:

[0090]

[0091] in, n ( t () represents neutron density, which is the number of neutrons per unit volume, and varies with time.

[0092] Ci ( t ) indicates the first i The density of slow-emitting neutron precursor nuclei varies over time;

[0093] ρ ( t ) indicates reactivity, and When the reactivity value is 1, the rate of neutron production in the reactor is equal to the rate of neutron disappearance.

[0094] k eff It represents the effective neutron multiplication factor, which is the ratio of the production rate to the disappearance rate of all neutrons in the reactor core;

[0095] This represents the total delayed neutron share, which is equal to the sum of the delayed neutron shares of all groups, i.e.; ;

[0096] Indicates the first i The proportion of slow-emission neutrons in the group;

[0097] Λ The neutron generation time is represented by the pulsed neutron source method, which is calculated using Monte Carlo simulation to make it suitable for cases with shallow subcriticality.

[0098] λ i Indicates the first i The decay constant of the slow-emitting neutron precursor nucleus;

[0099] I This indicates the number of delayed neutron groups, usually taken as... I =6, used to correspond to six groups of delayed neutrons;

[0100] This represents an external neutron source, where, for continuous beam operation mode, A constant value is adopted; for pulsed beam operation mode, based on the beam characteristics generated by the pulsed beam high-energy proton accelerator and the mechanism by which protons interact with the heavy metal target to produce neutrons. Modeled as a Gaussian impulse, that is: ,in, The amplitude of the pulse. The standard deviation of the Gaussian pulse. The pulse number. This represents the time interval between adjacent pulses.

[0101] Furthermore, in step S3, the step of obtaining dynamic parameters in the reactor model based on the reactor model and the accelerator includes: the total delayed neutron fraction. , No. i The share of slow-emission neutrons Neutron generation time Λ、 No. i decay constant of slow-emitting neutron precursor nuclei λ i .

[0102] In this embodiment, for the established externally perturbed point reactor neutron dynamics equations, the effective multiplication factor in the reactor model can be obtained based on the reactor model and the accelerator. k eff Thus, reactivity can be obtained. ρ ( t ), neutron generation time Λ The results were obtained using the pulse source method combined with Monte Carlo calculations.

[0103] Total delayed neutron share This is equal to the sum of the delayed neutron shares of all groups, i.e.; It can be made by each group Based on the material properties of each structure in the reactor model, the remaining parameters of the neutron dynamics equations for the externally perturbed reactor, namely the decay constant, were determined. λ i , No. i The share of slow-emission neutrons The nuclear database can be retrieved based on the settings of the corresponding materials in the reactor model. The nuclear database can be found in: WALDO RW, DELAGUARDIA R, KAPLAN A. Delayed neutron yields: Time dependent measurements and a predictive model[J]. Physical Review C, 1981, 23(3): 1121-1127.

[0104] According to one embodiment of the present invention, in step S4, the step of determining the upper limit of the power of the reactor model based on the temperature limit of each structure in the reactor model, the temperature limit of each structure is based on the temperature corresponding to the melting point of the material of each structure; wherein, based on the aforementioned settings, if the material composition of each structure is known, the corresponding melting point temperature can be obtained by querying an existing database, and used as the corresponding temperature limit.

[0105] Furthermore, the step of determining the upper power limit of the reactor model based on the temperature limits of each structure in the reactor model includes:

[0106] Set the time step; where the time step is selected as 10. -8 s-scale;

[0107] Based on the constructed reactor model and the configuration schemes of the two accelerator operation modes, the power distribution (i.e., energy deposition) of the fuel zone within each time step is calculated. Specifically, for the continuous beam operation mode, the first current intensity of the first accelerator is set such that the material temperature rise caused by energy deposition from the spallation reaction of the central heavy metal target is within a safe limit. The values ​​of the second current intensity and the first rotation speed of the second accelerator should be set such that the current intensity received by the three surrounding heavy metal targets is equal to the first current intensity. For the pulsed beam operation mode, the first fixed frequency of the first accelerator is set such that the material temperature rise caused by energy deposition from the spallation reaction of the central heavy metal target is within a safe limit. The second fixed frequency of the second accelerator is set to three times the first fixed frequency, and the value of the second rotation speed of the second accelerator is set to be the same as the value of the first fixed frequency. This ensures that the material temperature rise caused by energy deposition from the spallation reaction of each surrounding heavy metal target is within a safe limit, fully guaranteeing the operational reliability and stability of this scheme.

[0108] The spatial distribution of the temperature field in the fuel zone is calculated by combining the physical properties of the coolant in the fuel zone and the obtained power distribution of the fuel zone.

[0109] If a location in the temperature field spatial distribution exceeds the temperature limit, the power distribution corresponding to the current temperature field distribution is not allowed. That is, it is determined that the reactor power that generates the power distribution under the current conditions exceeds the power limit of the reactor model.

[0110] According to one embodiment of the present invention, in step S5, the step of adjusting the structural parameters of the reactor model includes adjusting the center distance between the surrounding heavy metal target and the central heavy metal target; in the step of adjusting the operating parameters of the accelerator, for continuous beam operation mode, the step includes adjusting the first current intensity of the first accelerator and adjusting the second current intensity and the first rotation speed of the second accelerator. For pulse beam operation mode, the step includes adjusting the first fixed frequency of the first accelerator and adjusting the second fixed frequency and the second rotation speed of the second accelerator.

[0111] To further illustrate this plan, an example is provided.

[0112] Based on the aforementioned steps, a corresponding reactor model and accelerator 5 are established and configured. Specifically, the power target of the reactor model in this scheme is set to 1000MW. For continuous beam operation mode, the energy of the first accelerator 5a used to bombard the central heavy metal target 41 is 1.5GeV, and the first current intensity is 10mA; the energy of the second accelerator 5b used to alternately bombard the surrounding heavy metal targets 42 is 1.5GeV, and the second current intensity is 10mA. Furthermore, to achieve bombardment of the surrounding heavy metal targets 42, the second accelerator 5b is arranged on a circular track with an initial radius of 17.3cm, and the first rotational speed of the second accelerator 5b along the circular track is set to 1M revolutions / second. For the pulse beam operation mode, the first fixed frequency of the first accelerator 5a used to bombard the central heavy metal target 41 is 1 MHz; the second fixed frequency of the second accelerator 5b used to bombard the surrounding heavy metal targets 42 in turn is 3 MHz; furthermore, in order to achieve bombardment of the surrounding heavy metal targets 42, the second pulse beam accelerator 5b is arranged on a circular track with an initial radius of 17.3 cm, and the second rotation speed of the second pulse beam accelerator 5b along the circular track is set to be the same as the value of the first fixed frequency, that is, 1 M revolutions / second.

[0113] In this embodiment, the radial outer radius of the radial shielding layer portion 12 is 258.285 cm, the radial thickness is 22.445 cm, and the axial height is 190 cm; the radial radius of the axial shielding layer portion 11 is 190.956 cm, and the axial thickness is 5 cm; the radial outer radius of the radial reflective layer portion 22 is 235.84 cm, the radial thickness is 44.884 cm, and the axial height is 190 cm; and the radial radius of the axial reflective layer portion 21 is 190.956 cm, and the axial thickness is 40 cm.

[0114] The parameters of shielding layer 1 and reflective layer 2 are summarized in Table 1.

[0115] Table 1

[0116]

[0117] In this embodiment, the radial radius of the fuel zone 3 is 190.956 cm and the axial height is 100 cm.

[0118] In this embodiment, the radial radius of the heavy metal target 4 is 12.96 cm, and the axial height of the heavy metal target 4 is 190 cm.

[0119] The parameters of fuel zone 3 and heavy metal target 4 are summarized as shown in Table 2.

[0120] Table 2

[0121]

[0122] The positions of the central heavy metal target 41 and the surrounding heavy metal targets 42 correspond to the positions of the first accelerator 5a and the second accelerator 5b.

[0123] The parameters in the neutron dynamics equations for the externally disturbed point reactor are set as shown in Tables 3 and 4.

[0124] Table 3

[0125]

[0126] Table 4

[0127]

[0128] Based on the above settings, simulations were initiated using both continuous beam and pulsed beam operation modes. A comprehensive evaluation and summary were conducted from the perspectives of neutron energy spectrum, total neutron flux in fuel region 3, and the fission reaction ratios of MA and Pu. It was found that a radius of 17.32 cm for the annular orbits of the surrounding heavy metal targets 42 met the requirements. (See [link to relevant documentation]). Figure 6 and Figure 7 .

[0129] Furthermore, by changing the different accelerator frequencies of the first accelerator 5a and the second accelerator 5b in the pulse beam operation mode, and summarizing the reactor power levels of the reactor model, as shown in... Figure 8 As shown ( Figure 8 The vertical axis represents the normalized power (a multiple of the initial power). It can be seen that, based on the determined radius of the annular orbit of the surrounding heavy metal target 42, the power of the reactor model in this scheme can meet the design target of 1000MW.

[0130] The above description is merely an example of a specific solution of the present invention. For any devices and structures not described in detail herein, it should be understood that they are implemented using common devices and methods already available in the art.

[0131] The above description is merely one embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A design method for a four-proton beam ADS device, characterized in that, Includes the following steps: S1. Establish a reactor model, wherein the reactor model includes a shielding layer, a reflector layer, a fuel zone, and a heavy metal target; the heavy metal target includes: a central heavy metal target and three surrounding heavy metal targets; S2. An accelerator is arranged for the heavy metal target, wherein there are two accelerators, namely a first accelerator for bombarding the central heavy metal target and a second accelerator for bombarding the three surrounding heavy metal targets in turn, so as to generate a four-proton beam. S3. Establish the neutron dynamics equations for an externally perturbed point reactor; wherein, dynamic parameters in the reactor model are obtained based on the reactor model and the accelerator; S4. Determine the upper power limit of the reactor model based on the temperature limits of each structure in the reactor model; wherein, the temperature limit of each structure is based on the temperature corresponding to the melting point of the material of each structure. S5. If the reactor power exceeds the power limit, adjust the structural parameters of the reactor model and the operating parameters of the accelerator; In step S2, the step of arranging accelerators for the heavy metal target is that the accelerators adopt either a continuous beam operation mode or a pulse beam operation mode. When the continuous beam operation mode is adopted, both the first accelerator and the second accelerator adopt continuous beam high-energy proton accelerators. When the pulse beam operation mode is adopted, both the first accelerator and the second accelerator adopt pulse beam high-energy proton accelerators. For continuous beam operation mode, the first accelerator bombards the central heavy metal target at a first flux intensity, and the second accelerator bombards the three surrounding heavy metal targets alternately at a second flux intensity and a first rotation speed; wherein, the first flux intensity of the first accelerator is set such that the material temperature rise caused by energy deposition from the spallation reaction of the central heavy metal target is within a safe limit; wherein, the safe limit is set based on the temperature corresponding to the melting point of the material of each structure in the reactor model; The second current intensity and the first rotational speed of the second accelerator are set such that the material temperature rise caused by energy deposition from the spallation reaction of each surrounding heavy metal target is within a safe limit; wherein the safe limit is set based on the temperature corresponding to the melting point of the material of each structure in the reactor model; For the pulse beam operation mode, the first accelerator bombards the central heavy metal target at a first fixed frequency, and the second accelerator bombards the three surrounding heavy metal targets in turn at a second fixed frequency and a second rotation speed; wherein, the first fixed frequency of the first accelerator is set so that the material temperature rise caused by the energy deposition of the central heavy metal target due to the spallation reaction is within a safe limit; wherein, the safe limit is set based on the temperature corresponding to the melting point of the material of each structure in the reactor model. The second fixed frequency and the second rotational speed of the second accelerator are set such that the material temperature rise caused by energy deposition from the spallation reaction of each surrounding heavy metal target is within a safe limit; wherein the safe limit is based on the temperature setting corresponding to the material melting point of each structure in the reactor model.

2. The design method of the four-proton beam ADS device according to claim 1, characterized in that, In the reactor model, the three surrounding heavy metal targets are evenly distributed on a circle centered on the central heavy metal target.

3. The design method of the four-proton beam ADS device according to claim 2, characterized in that, In the reactor model, the reflective layer covers the outside of the fuel zone, and the shielding layer covers the outside of the reflective layer; The reflective layer includes: an axial reflective layer portion and a radial reflective layer portion; The axial reflective layer is respectively provided at both ends of the axial direction of the fuel zone; The shielding layer includes: an axial shielding layer portion and a radial shielding layer portion; The axial shielding layer portion is disposed on the outside of the axial reflective layer portion; The axial shielding layer is provided with a first channel through which the heavy metal target passes; The axial reflective layer is provided with a second channel through which the heavy metal target passes; The fuel zone is provided with a third channel for the insertion of the heavy metal target; The central heavy metal target is positioned at the center of the fuel zone.

4. The design method of the four-proton beam ADS device according to claim 3, characterized in that, The thickness of the axial reflective layer portion is greater than the thickness of the axial shielding layer portion; The thickness of the radial reflective layer portion is greater than the thickness of the radial shielding layer portion; The axial shielding layer is made of 57% LBE material and 43% T91 steel. The axial reflective layer is made of 57% LBE material and 43% T91 steel. The radial shielding layer is made of 9.4% LBE material, 10.6% T91 steel and 80% boron carbide. The radial reflective layer is made of 93.1% LBE material and 6.9% T91 steel.

5. The design method of the four-proton beam ADS device according to claim 4, characterized in that, The fuel zone includes the fuel portion, coolant, support structure, and pore gaps; In the fuel zone, the fuel portion accounts for 24.33%, the coolant portion accounts for 57%, the support structure portion accounts for 16.67%, and the pore gap portion accounts for 2%. The coolant is made of a lead-bismuth alloy; The supporting structure is made of T91 steel; The composition of the fuel portion is determined according to the pressurized water reactor unloading ratio, and the ratio of minor actinides to plutonium is 1.1 / 8.

9. The fuel portion includes: 35.35% lead, 28.92% bismuth, 12.76% iron, 14.24% zirconium, 3.30% plutonium, 2.14% americium, and 3.29% filler. The filler is at least one of chromium, tungsten, manganese, vanadium, carbon, silicon, tantalum, neptunium, and curium.

6. The design method of the four-proton beam ADS device according to claim 5, characterized in that, The fuel section has 2% pore gaps, and the pore gaps are evenly distributed in the fuel section.

7. The design method of the four-proton beam ADS device according to claim 6, characterized in that, The heavy metal target is made of 55.00% lead and 45.00% bismuth.

8. The design method of the four-proton beam ADS device according to claim 7, characterized in that, In step S3, the step of establishing the neutron dynamics equations for an externally perturbed point pile is expressed as follows: in, n ( t The neutron density () represents the number of neutrons per unit volume, which changes with time. t change; C i ( t ) indicates the first i The density of slow-emitting neutron precursor nuclei over time t change; ρ ( t ) indicates reactivity, and When the reactivity value is 1, the rate of neutron production in the reactor is equal to the rate of neutron disappearance. k eff It represents the effective neutron multiplication factor, which is the ratio of the production rate to the disappearance rate of all neutrons in the reactor core; β This represents the total delayed neutron share, which is equal to the sum of the delayed neutron shares of all groups, i.e.; ; β i Indicates the first i The proportion of slow-emission neutrons in the group; Λ Indicates neutron generation time; λ i Indicates the first i The decay constant of the slow-emitting neutron precursor nucleus; I Indicates the number of delayed neutron groups, taking... I =6, used to correspond to six groups of delayed neutrons; This represents an external neutron source, where, for continuous beam operation mode, A constant value is adopted; for pulsed beam operation mode, based on the beam characteristics generated by the pulsed beam high-energy proton accelerator and the mechanism by which protons interact with the heavy metal target to produce neutrons. Modeled as a Gaussian impulse, that is: ,in, The amplitude of the pulse. The standard deviation of the Gaussian pulse. The pulse number. The time interval between adjacent pulses; In step S3, the step of obtaining the dynamic parameters in the reactor model based on the reactor model and the accelerator includes the following dynamic parameters: total delayed neutron fraction. β , No. i The share of slow-emission neutrons β i Neutron generation time Λ、 No. i decay constant of slow-emitting neutron precursor nuclei λ i .

9. The design method of the four-proton beam ADS device according to claim 8, characterized in that, In step S5, the step of adjusting the structural parameters of the reactor model is used to adjust the center distance between the surrounding heavy metal target and the central heavy metal target. In step S5, the step of adjusting the operating parameters of the accelerator includes, for continuous beam operation mode, adjusting the first current intensity of the first accelerator and adjusting the second current intensity and first rotation speed of the second accelerator. For the pulse beam operation mode, adjust the first fixed frequency of the first accelerator, and adjust the second fixed frequency and second rotation speed of the second accelerator.

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