A partitioned arrangement of graphite-based dispersed fuel heat pipe reactor core structure

Abstract

The application discloses a kind of partition arrangement's graphite-based dispersion fuel heat pipe reactor core structure, and low enrichment uranium fuel area center is equipped with the guide hole of adaptation emergency stop rod insertion, low enrichment uranium fuel area outside is successively coated high enrichment uranium fuel area, intermediate enrichment uranium fuel area, neutron reflector, inner shell, shielding layer and outer shell;Three uranium fuel areas are uniformly distributed with multiple heat pipe guide holes suitable for inserting heat pipe;Neutron reflector is uniformly distributed with multiple circular rotating holes suitable for rotating reactivity control drum in it in the middle, and the entire lateral wall of reactivity control drum is provided with arc length 120 degrees and cross section in the form of crescent-shaped neutron absorbing material layer along its circumference, which together with the cross section of reactivity control drum forms a circle;It can effectively flatten the core power, significantly improve the reliability and system economy of nuclear reactor operation;And all-solid-state core is more conducive to transportation, expands the application range;It can be used for power generation, and can also provide high-temperature process heat, with multi-purpose characteristics.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nuclear reactor engineering, in particular to a graphite-based dispersed fuel heat pipe reactor core structure arranged in zones. BACKGROUND

[0002] Currently, the heat pipe reactor uses heat pipes to replace fluid coolants to carry away the heat of the reactor core. The reactor core is a solid core. When the heat pipe reactor is running, the fission energy generated by the nuclear reactor is conducted to the evaporation section of the metal heat pipe arranged in the reactor core. Through the evaporation, condensation process and natural circulation flow of the working medium inside the heat pipe, the heat is conducted from the reactor core to the hot end of the heat and power conversion device / two-loop system. After the heat and power conversion device / two-loop system converts the heat energy into electric energy, the remaining waste heat is discharged to the final heat sink (atmosphere or environment) through the cooler or radiator.

[0003] Due to the core advantages of the heat pipe reactor, such as solid state, high inherent safety, simple operating characteristics, easy modularity, easy expansion and good transportation characteristics, the heat pipe reactor has broad application prospects in deep space exploration and propulsion, land-based nuclear power supply, deep sea exploration and other environments.

[0004] However, on the one hand, due to the compact structure and simple design of the traditional heat pipe reactor, the neutron leakage in the heat pipe reactor is strong, the power unevenness coefficient is high, which limits the total power output of the whole reactor core, and is not conducive to system economy; on the other hand, due to the high operating temperature and poor heat conduction of the reactor core of the heat pipe reactor, the reactor core generates very high thermal stress, which endangers the safety of the nuclear reactor. SUMMARY

[0005] In view of the deficiencies of the current traditional heat pipe reactor core design scheme, the purpose of the present application is to provide a new solution that can effectively improve the heat transfer characteristics of the reactor core, enhance the stability and reliability of the heat pipe reactor during operation, flatten the power distribution of the reactor core, reduce the neutron leakage rate, improve the system economy, and have good realizability.

[0006] The technical scheme of the present application is as follows: a graphite-based dispersed fuel heat pipe reactor core structure arranged in zones, which is composed of an emergency shutdown rod, a low-enriched uranium fuel zone, a high-enriched uranium fuel zone, an intermediate-enriched uranium fuel zone, a neutron reflector, a reactivity control drum, a neutron absorbing material layer, an inner shell, a shielding layer, an outer shell and a heat pipe; wherein,

[0007] The low-enriched uranium fuel zone is provided with an emergency shutdown rod guide hole adapted for the insertion of the emergency shutdown rod, the high-enriched uranium fuel zone is wrapped outside the low-enriched uranium fuel zone, the intermediate-enriched uranium fuel zone is wrapped outside the high-enriched uranium fuel zone, the neutron reflector is wrapped outside the intermediate-enriched uranium fuel zone, the inner shell is wrapped outside the neutron reflector, the shielding layer is wrapped outside the inner shell, and the outer shell is wrapped outside the shielding layer.

[0008] The low-enriched uranium fuel region, the high-enriched uranium fuel region and the medium-enriched uranium fuel region are uniformly distributed with multiple heat pipe guide holes suitable for inserting heat pipes; the evaporation section at the bottom of the heat pipe is used for inserting into the core, while the adiabatic section in the middle of the heat pipe and the condensation section at the upper part of the heat pipe are both extended from above the core;

[0009] The neutron reflecting layer is uniformly distributed with multiple rotating holes suitable for inserting the reactivity control drums, and each reactivity control drum is in the shape of a cylinder and can rotate in the single rotating hole of the neutron reflecting layer.

[0010] The side wall of each reactivity control drum is provided with a layer of neutron absorbing material with an arc length of 120 degrees and a certain thickness along the circumference thereof, the cross section of the layer of neutron absorbing material is in the shape of a crescent, and the layer of neutron absorbing material and the cross section of the reactivity control drum together form a circle; the layer of neutron absorbing material extends from the top end of the reactivity control drum to the bottom of the reactivity control drum, and the layer of neutron absorbing material can rotate together with the reactivity control drum.

[0011] The partitioned graphite-based dispersed fuel heat pipe reactor core structure, wherein the low-enriched uranium fuel region is a circular low-enrichment fuel column, the high-enriched uranium fuel region is composed of multiple fan-shaped high-enrichment fuel columns, the medium-enriched uranium fuel region is composed of multiple fan-shaped medium-enrichment fuel columns, and gaps or air gaps are left between adjacent fuel columns.

[0012] The partitioned graphite-based dispersed fuel heat pipe reactor core structure, wherein the low-enriched uranium fuel region is a low-enrichment fuel column in the shape of a regular 5-16-sided polygon, the high-enriched uranium fuel region is composed of multiple trapezoidal high-enrichment fuel columns, the medium-enriched uranium fuel region is composed of multiple trapezoidal medium-enrichment fuel columns, and gaps or air gaps are left between adjacent fuel columns.

[0013] The partitioned graphite-based dispersed fuel heat pipe reactor core structure, wherein the low-enriched uranium fuel region is a low-enrichment fuel column in the shape of a regular hexagon, the high-enriched uranium fuel region is composed of six trapezoidal high-enrichment fuel columns, the medium-enriched uranium fuel region is composed of six trapezoidal medium-enrichment fuel columns, and gaps or air gaps are left between the medium-enrichment fuel columns, between the medium-enrichment fuel columns and the high-enrichment fuel columns, between the high-enrichment fuel columns, and between the high-enrichment fuel columns and the low-enrichment fuel columns.

[0014] The partitioned graphite-based dispersed fuel heat pipe reactor core structure, wherein the low-enrichment fuel column, the high-enrichment fuel column and the medium-enrichment fuel column are all made of a honeycomb-shaped porous column body made of a composite material in which fuel particles are dispersedly and randomly distributed in a graphite matrix.

[0015] The partitioned graphite-based dispersion fuel heat pipe reactor core structure, wherein the fuel particle is composed of a UO2 core, a low-density loose pyrolytic carbon layer, an inner dense isotropic pyrolytic carbon layer, a silicon carbide layer and an outer dense isotropic pyrolytic carbon layer; the outer dense isotropic pyrolytic carbon layer is wrapped outside the silicon carbide layer, the silicon carbide layer is wrapped outside the inner dense isotropic pyrolytic carbon layer, the inner dense isotropic pyrolytic carbon layer is wrapped outside the low-density loose pyrolytic carbon layer, and the low-density loose pyrolytic carbon layer is wrapped outside the UO2 core.

[0016] The partitioned graphite-based dispersion fuel heat pipe reactor core structure, wherein the fuel particle in the low-enrichment fuel column is composed of a low-enrichment UO2 core, the fuel particle in the high-enrichment fuel column is composed of a high-enrichment UO2 core, and the fuel particle in the intermediate-enrichment fuel column is composed of an intermediate-enrichment UO2 core.

[0017] The partitioned graphite-based dispersion fuel heat pipe reactor core structure, wherein the material of the emergency shutdown rod, the neutron absorption material layer and / or the shielding layer is boron carbide, and the material of the neutron reflection layer and the reactivity control drum is aluminum oxide.

[0018] The partitioned graphite-based dispersion fuel heat pipe reactor core structure, wherein the material of the inner shell and the outer shell is stainless steel, and a gap is left between the inner shell and the neutron reflection layer.

[0019] The partitioned graphite-based dispersion fuel heat pipe reactor core structure, wherein sodium is used as the internal working medium of the heat pipe.

[0020] Compared with the heat pipe reactor core structure in the prior art, the partitioned graphite-based dispersion fuel heat pipe reactor core structure has the following beneficial effects:

[0021] The use of three different enrichment levels of nuclear fuel and the radial partitioning of the fuel can flatten the core power distribution, greatly improve the operation reliability and system economy of the nuclear reactor, and the use of graphite as the base dispersion fuel, i.e., the random distribution of fuel particles in the graphite matrix, eliminates the gap between the fuel and the matrix, greatly improves the heat transfer characteristics of the core, effectively reduces the peak temperature of the core matrix, and simplifies the operation of the entire nuclear reactor.

[0022] Based on the heat pipe reactor core design of the application, due to the high core operation temperature, the application has wide application in deep space exploration and propulsion, land-based nuclear power supply, deep sea exploration and other scenes, and if supplemented by corresponding secondary circuit equipment, the application can also realize conventional power supply and provide high-temperature process heat, so the core design of the application also has the characteristics of multiple purposes. BRIEF DESCRIPTION OF DRAWINGS

[0023] The drawings described herein are only for illustrative purposes, and are not intended to limit the scope of the present application in any way; the shapes and scale sizes of the components in the drawings are only illustrative, and are used to help understand the application, and are not specific limitations on the shapes and scale sizes of the components of the application; those skilled in the art can select various possible shapes and scale sizes according to specific circumstances to implement the application under the teaching of the application.

[0024] Figure 1 is a cross-sectional schematic view of a graphite-based dispersed fuel heat pipe reactor core structure embodiment arranged in zones according to the application;

[0025] Figure 2 is a three-dimensional schematic view of the whole of a graphite-based dispersed fuel heat pipe reactor core structure embodiment arranged in zones according to the application;

[0026] Figure 3 is a cross-sectional schematic view of a fuel zone used in a graphite-based dispersed fuel heat pipe reactor core structure embodiment arranged in zones according to the application;

[0027] Figure 4 is a three-dimensional structural schematic view of three fuel columns used in a graphite-based dispersed fuel heat pipe reactor core structure embodiment arranged in zones according to the application;

[0028] Figure 5 is a structural schematic view of fuel particles used in a graphite-based dispersed fuel heat pipe reactor core structure embodiment arranged in zones according to the application.

[0029] Summary of the reference numbers in the drawings: 1 - emergency shutdown rod; 2 - low enrichment fuel zone; 3 - high enrichment fuel zone; 4 - intermediate enrichment fuel zone; 5 - neutron reflector; 6 - reactivity control drum; 7 - neutron absorbing material layer; 8 - inner shell; 9 - shielding layer; 10 - outer shell; 11 - heat pipe; 12 - emergency shutdown rod guide hole; 13 - heat pipe guide hole; 14 - low enrichment fuel column; 15 - high enrichment fuel column; 16 - intermediate enrichment fuel column; 17 - fuel particle; 18 - outer dense isotropic pyrolytic carbon layer; 19 - silicon carbide layer; 20 - inner dense isotropic pyrolytic carbon layer; 21 - low-density loose pyrolytic carbon layer; 22 - UO2 core. DETAILED DESCRIPTION

[0030] The specific embodiments and examples of the present application will be described in detail below with reference to the accompanying drawings, which are described to explain the present application, but not to limit the specific embodiments of the present application.

[0031] As Figure 1 and in combination Figure 2 and Figure 3 The present application provides a partitioned graphite-based dispersion fuel heat pipe reactor core structure, which is composed of an emergency shutdown rod 1, a low-enriched uranium fuel area 2, a high-enriched uranium fuel area 3, an intermediate-enriched uranium fuel area 4, a neutron reflector 5, a reactivity control drum 6, a neutron absorbing material layer 7, an inner shell 8, a shielding layer 9, an outer shell 10 and a heat pipe 11; wherein,

[0032] The low-enriched uranium fuel area 2 is provided with an emergency shutdown rod guide hole 12 adapted to the insertion of the emergency shutdown rod 1 at the center, the high-enriched uranium fuel area 3 is coated on the outer side of the low-enriched uranium fuel area 2, the intermediate-enriched uranium fuel area 4 is coated on the outer side of the high-enriched uranium fuel area 3, the neutron reflector 5 is coated on the outer side of the intermediate-enriched uranium fuel area 4, the inner shell 8 is wrapped on the outer side of the neutron reflector 5, the shielding layer 9 is wrapped on the outer side of the inner shell 8, and the outer shell 10 is wrapped on the outer side of the shielding layer 9;

[0033] The low-enriched uranium fuel area 2, the high-enriched uranium fuel area 3 and the intermediate-enriched uranium fuel area 4 are all uniformly provided with a plurality of heat pipe guide holes 13 adapted to the insertion of the heat pipe 11; the evaporation section at the bottom of the heat pipe 11 is used for insertion into the reactor core, while the adiabatic section in the middle of the heat pipe 11 and the condensation section at the upper part of the heat pipe 11 both extend out from above the reactor core;

[0034] The neutron reflector 5 is uniformly provided with a plurality of rotating holes adapted to the insertion of the reactivity control drum 6, and the shape of a single reactivity control drum 6 is a cylinder and can rotate in a single rotating hole of the neutron reflector 5;

[0035] The sidewall of each reactivity control drum 6 is provided with a neutron absorbing material layer 7 with an arc length of 120 degrees and a certain thickness along the circumference thereof, the cross section of the neutron absorbing material layer 7 is crescent-shaped, and together with the cross section of the reactivity control drum 6, forms a circle; the neutron absorbing material layer 7 extends from the top end of the reactivity control drum 6 to the bottom of the reactivity control drum 6, so that when the neutron absorbing material layer 7 rotates to a corresponding angle with the reactivity control drum 6, the reactivity of the nuclear reactor can be controlled, and then the start, power regulation and shutdown of the nuclear reactor can be controlled.

[0036] An embodiment of the core structure of the zoned graphite-based dispersion fuel heat pipe reactor is that the low-enriched uranium fuel zone 2 is a circular low-enriched fuel column, the high-enriched uranium fuel zone 3 is composed of multiple fan-shaped high-enriched fuel columns, and the intermediate-enriched uranium fuel zone 4 is composed of multiple fan-shaped intermediate-enriched fuel columns, and gaps or air gaps are left between adjacent fuel columns to meet the volume change of thermal expansion.

[0037] Another embodiment of the core structure of the zoned graphite-based dispersion fuel heat pipe reactor is that the low-enriched uranium fuel zone 2 is a regular polygonal low-enriched fuel column with 5-16 sides, the high-enriched uranium fuel zone 3 is composed of multiple trapezoidal high-enriched fuel columns, and the intermediate-enriched uranium fuel zone 4 is composed of multiple trapezoidal intermediate-enriched fuel columns, and gaps or air gaps are left between adjacent fuel columns to meet the volume change of thermal expansion.

[0038] Taking a regular hexagon as an example, as shown in FIG. 1, Figure 4 the low-enriched uranium fuel zone 2 is a regular hexagonal low-enriched fuel column 14, the high-enriched uranium fuel zone 3 is composed of six trapezoidal high-enriched fuel columns 15, and the intermediate-enriched uranium fuel zone 4 is composed of six trapezoidal intermediate-enriched fuel columns 16, and gaps or air gaps are left between the intermediate-enriched fuel columns 16, between the intermediate-enriched fuel columns 16 and the high-enriched fuel columns 15, between the high-enriched fuel columns 15, and between the high-enriched fuel columns 15 and the low-enriched fuel columns 14 to meet the volume change of thermal expansion.

[0039] Further, the low-enriched fuel column 14, the high-enriched fuel column 15, and the intermediate-enriched fuel column 16 are all graphite-based dispersion fuel columns, that is, they are all honeycomb-shaped porous columns made of a composite material in which fuel particles 17 are dispersed and randomly distributed in a graphite matrix, wherein the filling ratio of the fuel particles 17, the position and number of the heat pipe guide holes 13 can be determined according to the operating temperature and (megawatt) power demand of the nuclear reactor.

[0040] Further, as shown in FIG. 2, Figure 5 the fuel particles 17 are composed of a UO2 core 22, a low-density loose pyrolytic carbon layer 21, an inner dense isotropic pyrolytic carbon layer 20, a silicon carbide layer 19, and an outer dense isotropic pyrolytic carbon layer 18; wherein the outer dense isotropic pyrolytic carbon layer 18 is wrapped outside the silicon carbide layer 19, the silicon carbide layer 19 is wrapped outside the inner dense isotropic pyrolytic carbon layer 20, the inner dense isotropic pyrolytic carbon layer 20 is wrapped outside the low-density loose pyrolytic carbon layer 21, and the low-density loose pyrolytic carbon layer 21 is wrapped outside the UO2 core 22.

[0041] Furthermore, the fuel particles 17 in the low-enrichment fuel column 14 are composed of UO2 cores 22 with low enrichment, the fuel particles 17 in the high-enrichment fuel column 14 are composed of UO2 cores 22 with high enrichment, and the fuel particles 17 in the intermediate-enrichment fuel column 14 are composed of UO2 cores 22 with intermediate enrichment.

[0042] Specifically, the scram rod 1 is made of boron carbide and is used for emergency shutdown of a nuclear reactor to ensure the controllability of the nuclear reactor.

[0043] Specifically, the neutron reflector 5 and the reactivity control drum 6 are both made of aluminum oxide, which is used to reflect neutrons toward the core. The neutron absorption material layer 7 is made of boron carbide, which is used to absorb neutrons from the core to improve the reactivity of the nuclear reactor.

[0044] Specifically, the inner shell 8 and the outer shell 10 are both made of stainless steel and are used to accommodate the core and protect the nuclear reactor system. The shielding layer 9 located between the inner shell 8 and the outer shell 10 is made of boron carbide and is used to absorb neutrons leaked from the neutron reflector 5 to reduce the radiation impact on the environment and improve the safety of the nuclear reactor.

[0045] Preferably, a gap or clearance is left between the inner shell 8 and the neutron reflector 5 .

[0046] Specifically, the heat pipe 11 preferably uses sodium as the internal working fluid to ensure the heat exchange efficiency of the core at a megawatt-level power.

[0047] The contents not described in detail in this specification belong to the existing technologies known to ordinary technicians in this field, such as UO2 cores with low enrichment, intermediate enrichment or high enrichment, low-density loose pyrolytic carbon layers, and the concept of diffuse random distribution.

[0048] It should be understood that the above description is only a preferred embodiment of the present invention and is not sufficient to limit the technical solutions of the present invention. For ordinary technicians in this field, within the spirit and principles of the present invention, additions, substitutions, changes or improvements can be made according to the above description, and all these additions, substitutions, changes or improvements should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A zoned graphite-based diffused fuel heat pipe reactor core structure, characterized in that: It consists of emergency shutdown rods, low-enriched uranium fuel area, high-enriched uranium fuel area, intermediate-enriched uranium fuel area, neutron reflector, reactivity control drum, neutron absorption material layer, inner shell, shielding layer, outer shell and heat pipe; among them, A scram rod guide hole adapted for inserting a scram rod is provided at the center of the low-enriched uranium fuel zone; the high-enriched uranium fuel zone is coated on the outside of the low-enriched uranium fuel zone; the intermediate-enriched uranium fuel zone is coated on the outside of the high-enriched uranium fuel zone; the neutron reflector is coated on the outside of the intermediate-enriched uranium fuel zone; the inner shell is coated on the outside of the neutron reflector; the shielding layer is coated on the outside of the inner shell; and the outer shell is coated on the outside of the shielding layer. The low-enriched uranium fuel zone, the high-enriched uranium fuel zone, and the intermediate-enriched uranium fuel zone are all provided with a plurality of heat pipe guide holes adapted for inserting heat pipes. The evaporation section at the bottom of the heat pipe is inserted into the reactor core, while the insulation section in the middle of the heat pipe and the condensation section at the top of the heat pipe both extend from above the reactor core. A plurality of rotating holes adapted to be inserted into the reactivity control drum are evenly distributed in the neutron reflector. A single reactivity control drum is cylindrical in shape and can rotate in a single rotating hole in the neutron reflector. A neutron-absorbing material layer of a certain thickness is provided on the sidewall of each reactivity control drum along its circumference. The neutron-absorbing material layer has a crescent-shaped cross-section, which together with the cross-section of the reactivity control drum forms a circle. The neutron-absorbing material layer extends from the top of the reactivity control drum to the bottom of the reactivity control drum and can rotate with the reactivity control drum.

2. The zoned graphite-based diffused fuel heat pipe reactor core structure according to claim 1 is characterized in that: The low-enriched uranium fuel zone is a circular low-enrichment fuel column, the high-enriched uranium fuel zone is composed of multiple fan-shaped high-enrichment fuel columns, and the intermediate-enriched uranium fuel zone is composed of multiple fan-shaped intermediate-enrichment fuel columns, and gaps or air gaps are left between adjacent fuel columns.

3. The zoned graphite-based diffused fuel heat pipe reactor core structure according to claim 1 is characterized in that: The low-enriched uranium fuel zone is a regular polygon with regular 5 to 16 sides and a low-enrichment fuel column. The high-enriched uranium fuel zone is composed of multiple trapezoidal high-enrichment fuel columns. The intermediate-enriched uranium fuel zone is composed of multiple trapezoidal intermediate-enrichment fuel columns, and gaps or air gaps are left between adjacent fuel columns.

4. The zoned graphite-based diffused fuel heat pipe reactor core structure according to claim 3 is characterized in that: The low-enriched uranium fuel zone is a regular hexagonal low-enrichment fuel column, the high-enriched uranium fuel zone is composed of 6 trapezoidal high-enrichment fuel columns, and the intermediate-enriched uranium fuel zone is composed of 6 trapezoidal intermediate-enrichment fuel columns, and gaps or air gaps are left between the intermediate-enrichment fuel columns, between the intermediate-enrichment fuel columns and the high-enrichment fuel columns, between the high-enrichment fuel columns, and between the high-enrichment fuel columns and the low-enrichment fuel columns.

5. The zoned graphite-based diffused fuel heat pipe reactor core structure according to claim 2 or 3, characterized in that: The low-enrichment fuel column, the high-enrichment fuel column and the intermediate-enrichment fuel column are all made of a composite material in which fuel particles are dispersed and randomly distributed in a graphite matrix to form a honeycomb-shaped porous column.

6. The zoned graphite-based diffused fuel heat pipe reactor core structure according to claim 5 is characterized in that: The fuel particles are composed of a UO2 core, a low-density loose pyrolytic carbon layer, an inner dense isotropic pyrolytic carbon layer, a silicon carbide layer, and an outer dense isotropic pyrolytic carbon layer; wherein the outer dense isotropic pyrolytic carbon layer is wrapped around the outside of the silicon carbide layer, the silicon carbide layer is wrapped around the outside of the inner dense isotropic pyrolytic carbon layer, the inner dense isotropic pyrolytic carbon layer is wrapped around the outside of the low-density loose pyrolytic carbon layer, and the low-density loose pyrolytic carbon layer is wrapped around the outside of the UO2 core.

7. The zoned graphite-based diffused fuel heat pipe reactor core structure according to claim 6 is characterized in that: The fuel particles in the low-enrichment fuel column are composed of UO2 cores with low enrichment, the fuel particles in the high-enrichment fuel column are composed of UO2 cores with high enrichment, and the fuel particles in the intermediate-enrichment fuel column are composed of UO2 cores with intermediate enrichment.

8. The zoned graphite-based diffused fuel heat pipe reactor core structure according to claim 1 is characterized in that: The materials used for the scram rod, neutron absorbing material layer and / or shielding layer are all boron carbide; the materials used for the neutron reflecting layer and the reactivity control drum are all aluminum oxide.

9. The zoned graphite-based diffused fuel heat pipe reactor core structure according to claim 1 is characterized in that: The inner shell and the outer shell are made of stainless steel, and a gap or clearance is left between the inner shell and the neutron reflection layer.

10. The zoned graphite-based diffused fuel heat pipe reactor core structure according to claim 1, characterized in that: The heat pipe uses sodium as the internal working medium.

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