A structurally compact high-throughput small multi-purpose lead-cooled fast reactor

Abstract

The present invention discloses a compact high-throughput small multi-purpose lead-cooled fast reactor, which includes an outer safety shell and an inner safety shell. A chamber is formed by surrounding the outer safety shell and the inner safety shell. The middle part of the inner safety shell is hollow to form a flux trap. An inner fuel region and an outer fuel region are sequentially arranged from the inside to the outside in the chamber. Fuel assemblies are arranged in both the inner fuel region and the outer fuel region. A safety plate is movably arranged between the inner fuel region and the inner safety shell. A plurality of regulating plates are movably arranged between the outer safety shell and the outer fuel region. Each regulating plate is circumferentially arranged along the outer fuel region and can move independently. The safety plate and the regulating plates are used to be inserted or pulled out along the axial direction of the lead-cooled fast reactor. Both the inner fuel region and the outer fuel region are communicated with the chamber. The chamber is used to fill with coolant lead. A reflector layer and a shielding layer are sequentially arranged on the outer peripheral side of the outer safety shell. This lead-cooled fast reactor is beneficial to realizing miniaturized development, and has high safety performance and wide applications.

Description

Technical Field

[0001] The invention relates to the fields of nuclear engineering and nuclear technology, and in particular to a compact high-flux small-scale multi-purpose lead-cooled fast reactor. Background Art

[0002] A lead-cooled fast reactor refers to a fast neutron reactor that is cooled by liquid lead or lead-bismuth alloy. It can well meet the safety, economy, sustainability and nuclear non-proliferation goals of the fourth-generation reactors, and is the most promising type of reactor among the six main types of fourth-generation reactors.

[0003] The development direction of lead-based fast reactors is mainly miniaturization, which is due to the characteristics of small reactors, such as small size, convenience, and wide application. Coolants such as lead or lead-bismuth have good physical parameters, such as high boiling point, high thermal conductivity, good thermal expansion, etc. They have good heat transfer performance, and avoid the core exposure caused by the boiling of coolant, preventing the occurrence of meltdown stories; compared with other coolants, lead or lead-bismuth is chemically inactive and is not easy to react chemically with other materials in the core; it has a strong natural circulation ability, which makes the lead-cooled fast reactor have good passive safety. These characteristics make lead-cooled fast reactors have great development potential, especially in the development of small modular reactors.

[0004] Most existing lead-cooled fast reactor fuel assembly designs use multiple fuel rods packaged into a fuel assembly, which generally has a complex structure and is not conducive to the miniaturization of lead-cooled fast reactors. Summary of the invention

[0005] In order to solve the technical problems mentioned in the background technology, the present invention provides a compact high-throughput small-scale multi-purpose lead-cooled fast reactor.

[0006] The technical solution adopted by the present invention is: a compact high-flux small multi-purpose lead-cooled fast reactor, comprising an outer containment shell and an inner containment shell, a chamber formed by the outer containment shell and the inner containment shell, the middle part of the inner containment shell is hollow to form a flux well, an inner fuel zone and an outer fuel zone distributed sequentially from the inside to the outside are arranged in the chamber, fuel assemblies are arranged in the inner fuel zone and the outer fuel zone, a safety plate is movably arranged between the inner fuel zone and the inner containment shell, a plurality of adjustment plates are movably arranged between the outer containment shell and the outer fuel zone, each of the adjustment plates is circumferentially arranged along the outer fuel zone and can move independently, the safety plate and the adjustment plate are used to be inserted or pulled out along the axial direction of the lead-cooled fast reactor, the inner fuel zone and the outer fuel zone are both connected to the chamber, the chamber is used to fill the coolant lead, and a reflecting layer and a shielding layer are sequentially arranged on the outer peripheral side of the outer containment shell.

[0007] It has at least the following beneficial effects: applying the plate-type fuel assembly commonly used in research reactors to lead-cooled fast reactors greatly enhances the overall heat transfer performance of the reactor, which is conducive to the miniaturization development of lead-cooled fast reactors; adopting a dual control system of inner and outer control plates to ensure the safety performance of the reactor; equipping a lead-cooled fast reactor with an irradiation channel, increasing the uses of the reactor and bringing additional economic benefits.

[0008] Further, the enrichment degrees of the fuel uranium-235 in the inner fuel region and the outer fuel region are set differently.

[0009] Further, the inner fuel region is set to 4 inner fuel region units, and the fuel assemblies located within the inner fuel region units are a number of arc-shaped plates arranged at intervals of 90° from inside to outside; the outer fuel region is set to 8 outer fuel region units, and the fuel assemblies located within the outer fuel region units are a number of arc-shaped plates arranged at intervals of 45° from inside to outside; cooling channels are formed between the arc-shaped plates, and the number of the regulating plates is 8.

[0010] Further, 8 guide rails are provided on the inner side of the outer safety shell, and guide grooves are provided on both sides of each guide rail, and the regulating plates are slidably arranged on the guide rails.

[0011] Further, a sleeve is provided on the outer side of the inner safety shell, the sleeve is hollow, and the safety plate reciprocates along the hollow part of the sleeve.

[0012] Further, the arc-shaped plate includes a fuel cladding, a fuel pellet is filled in the middle inside the fuel cladding, and a fission gas cavity and a reflector are symmetrically arranged at both ends of the fuel pellet along the axial direction in sequence.

[0013] Further, both the safety plate and the regulating plate include a control plate cladding, boron carbide as an absorption material is filled in the middle inside the control plate cladding, and tungsten as a metal material is filled at both ends.

[0014] Further, a positioning grid is provided in the chamber, the positioning grid is fixedly installed on the inner side of the outer safety shell and the outer side of the inner safety shell, the positioning grid includes side plates for separating the fuel regions, and both side portions of the arc-shaped plate are fixedly connected to the side plates.

[0015] Further, non-fuel sections are provided on both side portions of the arc-shaped plate, and the arc-shaped plate is connected to the side plate through the non-fuel sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following further illustrates the present invention with reference to the drawings and embodiments:

[0017] Figure 1 It is an axial sectional view of a compact high-flux small multi-purpose lead-cooled fast reactor provided by an embodiment of the present invention;

[0018] Figure 2 It is a radial cross-sectional view of a compact high-throughput small multi-purpose lead-cooled fast reactor provided by an embodiment of the present invention;

[0019] Figure 3 It is a schematic radial cross-sectional view of a fuel assembly in the inner fuel region of an embodiment of the present invention;

[0020] Figure 4 It is a schematic radial cross-sectional view of a fuel assembly in the outer fuel region of an embodiment of the present invention;

[0021] Figure 5 It is a schematic radial cross-sectional view of an arc plate in the inner fuel region of an embodiment of the present invention;

[0022] Figure 6 It is a schematic radial cross-sectional view of an arc plate in the outer fuel region of an embodiment of the present invention;

[0023] Figure 7 It is an axial cross-sectional view of the arc plate in an embodiment of the present invention;

[0024] Figure 8 It is a schematic axial cross-sectional view of the regulating plate and the safety plate in an embodiment of the present invention;

[0025] Figure 9 It is a schematic radial cross-sectional view of the regulating plate in an embodiment of the present invention;

[0026] Figure 10 It is a schematic radial cross-sectional view of the safety plate in an embodiment of the present invention.

[0027] Explanation of reference numerals: 1 - shielding layer, 2 - reflector, 3 - outer safety shell, 4 - regulating plate, 5 - chamber, 6 - annular fuel region, 7 - safety plate, 8 - inner safety shell, 9 - flux trap, 10 - inner fuel region, 11 - positioning grid, 12 - outer fuel region, 13 - arc plate, 14 - side plate, 15 - cooling channel, 16 - fuel cladding, 17 - fuel pellet, 18 - fission gas cavity, 19 - reflecting portion, 20 - boron carbide, 21 - tungsten, 22 - control plate cladding, 23 - guide rail, 24 - sleeve. Detailed Description of the Invention

[0028] This part will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the drawings. The function of the drawings is to supplement the description in the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be construed as a limitation on the protection scope of the present invention.

[0029] In the description of the present invention, it should be understood that with respect to the orientation description, for example, the orientation or positional relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0030] In the description of the present invention, the meaning of "several" is one or more, the meaning of "multiple" is more than two. Understandings such as "greater than", "less than", "exceeding", etc. do not include the present number, and understandings such as "above", "below", "within", etc. include the present number. If there is a description of "first" and "second", it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0031] In the description of the present invention, unless otherwise clearly defined, terms such as "set", "installed", "connected", etc. should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0032] Referring to Figures 1 to 10 , an embodiment of the present invention provides a compact high-throughput small multi-purpose lead-cooled fast reactor. Since there are various types of existing fuel assemblies, in research reactors, plate-type fuel elements are often used. The plate-shaped fuel is fixed on two side plates 14 to form a fuel assembly. The shapes of the fuel assemblies include circular ring, sector, regular polygon, etc. Since the plate-type fuel plate has sufficient contact area with the coolant, the plate-type fuel assembly has good heat transfer performance, and its core has the characteristics of small volume, high neutron flux, and high power density. The current development direction of lead-cooled fast reactors is mainly miniaturization, and the core of the plate-type fuel assembly just meets the requirements of its miniaturization.

[0033] Specifically, a structurally compact high-throughput small multi-purpose lead-cooled fast reactor includes an outer containment 3 and an inner containment 8. A chamber 5 is formed by enclosing the outer containment 3 and the inner containment 8. The middle of the inner containment 8 is hollow to form a flux trap 9. An inner fuel region 10 and an outer fuel region 12 are sequentially arranged from the inside to the outside in the chamber 5. Fuel assemblies are provided in both the inner fuel region 10 and the outer fuel region 12. A safety plate 7 is movably arranged between the inner fuel region 10 and the inner containment 8. A plurality of regulating plates 4 are movably arranged between the outer containment 3 and the outer fuel region 12. Each of the regulating plates 4 is circumferentially arranged along the outer fuel region 12 and can move independently. The safety plate 7 and the regulating plates 4 are used to insert or withdraw along the axis of the lead-cooled fast reactor. Both the inner fuel region 10 and the outer fuel region 12 communicate with the chamber 5. The chamber 5 is used to fill the coolant lead. A reflector layer 2 and a shielding layer 1 are sequentially arranged on the outer peripheral side of the outer containment 3.

[0034] Preferably, the enrichment degrees of the fuel uranium-235 in the inner fuel region 10 and the outer fuel region 12 are set differently.

[0035] Preferably, the inner fuel region 10 is set to 4 inner fuel region units. The fuel assemblies located in the inner fuel region units are a number of arc-shaped plates 13 arranged at 90° intervals from the inside to the outside; the outer fuel region 12 is set to 8 outer fuel region units. The fuel assemblies located in the outer fuel region units are a number of arc-shaped plates 13 arranged at 45° intervals from the inside to the outside; cooling channels 15 are formed between the arc-shaped plates 13. The number of the regulating plates 4 is 8.

[0036] Preferably, 8 guide rails 23 are arranged on the inner side of the outer containment 3. Both sides of each guide rail 23 have guide grooves. The regulating plates 4 are slidably arranged on the guide rails 23.

[0037] Preferably, a sleeve is arranged on the outer side of the inner containment 8. The sleeve is hollow. The safety plate 7 reciprocates along the hollow part of the sleeve.

[0038] Preferably, the arc-shaped plate 13 includes a fuel cladding 16. The middle of the fuel cladding 16 is filled with fuel pellets 17. Fission gas cavities 18 and reflection parts 19 are symmetrically arranged at both ends of the fuel pellets 17 along the axis in sequence.

[0039] Preferably, both the safety plate 7 and the regulating plates 4 include a control plate cladding 22. The middle of the control plate cladding 22 is filled with the absorber material boron carbide 20, and tungsten 21, a metal material, is filled at both ends.

[0040] Preferably, a positioning grid 11 is provided in the chamber 5. The positioning grid 11 is fixedly installed on the inner side of the outer containment 3 and the outer side of the inner containment 8. The positioning grid 11 includes side plates 14 for separating the annular fuel region 6, and both side portions of the arc-shaped plate 13 are fixedly connected to the side plates 14. The two side plates 14 in the inner fuel region 10 are arranged at 90°, and the two side plates 14 in the outer fuel region 12 are arranged at 45°.

[0041] Preferably, non-fuel sections are provided on both side portions of the arc-shaped plate 13, and the arc-shaped plate 13 is connected to the side plate 14 through the non-fuel sections.

[0042] Since the lead coolant has a corrosive effect on the cladding, especially when the coolant flow rate is relatively large, the corrosion is more serious. Therefore, an anti-corrosion coating can be added to the surface of the cladding. In some embodiments, the cladding materials of the arc-shaped plate 13, the regulating plate 4, and the safety plate 7 are all made of T91 stainless steel.

[0043] Meanwhile, in some embodiments, the material of the reflector 2 is a mixture of a certain proportion of T91 steel and lead; the material of the shield 1 is a mixture of a certain proportion of boron carbide 20 and lead.

[0044] In this embodiment, the structure of the high-flux small multi-purpose lead-cooled fast reactor is generally cylindrical, completely symmetric in the radial direction, and generally includes an intermediate irradiation region, an annular fuel region, a reflector region, and a shield region. The intermediate irradiation region is a cylindrical flux trap 9. The annular fuel region 6 is divided into an inner fuel region 10 and an outer fuel region 12, with a total of 12 fuel assemblies provided. Different fuel regions use fuels with different enrichment degrees. The inner fuel region 10 is provided with 4 fuel assemblies, each fuel assembly being a 1 / 4 cylindrical ring, and the fuel assembly is composed of arc-shaped plates 13 at 90°; the outer fuel region 12 is provided with 8 fuel assemblies, each fuel assembly being a 1 / 8 cylindrical ring, and the fuel assembly is composed of arc-shaped plates 13 at 45°. The fuel pellets 17 are in the middle of the arc-shaped plates 13, and fission gas cavities 18 and reflection portions 19 are symmetrically arranged at both ends. These arc-shaped plates 13 are fixed on the positioning grid 11, and the gap between the arc-shaped plates 13 is the cooling channel 15.

[0045] The safety plate 7 is a hollow cylinder. A sleeve is provided on the outer side of the inner containment 8 to guide the safety plate 7 to quickly insert into the core during an emergency shutdown. Under normal operating conditions, the safety plate 7 is in a pulled-out state, and this space is filled with coolant. The regulating plate 4 is correspondingly arranged in an arc shape and can be moved up and down independently. The space vacated after the movement is filled with coolant. Eight vertical guide grooves are uniformly arranged along the circumferential direction on the inner wall side of the outer containment 3 for the regulating plate 4 to move up and down, and the gap between the regulating plate 4 and the outer containment 3 is filled with coolant.

[0046] The present invention provides a lead-cooled fast reactor core structure with good safety performance, compact structure and multiple uses. First, in terms of safety performance, the present invention adopts a dual control system. One is the regulating plate 4 for regulating reactivity, and the reactivity of the reactor can be adjusted by changing the insertion depth of the regulating plate 4; the other is the safety plate 7 for emergency shutdown. When an emergency occurs, the safety plate 7 can quickly insert into the core to shut down the reactor. Both systems can independently mediate the reactor, ensuring the safety of the reactor. Secondly, the present invention adopts fuel zoning, and the enrichment degrees of fuel uranium-235 in the inner and outer zones are different, which is beneficial to flattening the power in the reactor. The fuel assembly adopts a plate-type fuel assembly. The plate-type fuel has better heat transfer capacity and radiation swelling resistance performance than rod-shaped fuel, and the coolant lead has better heat transfer performance than water, which greatly increases the heat transfer capacity of the reactor, so that the reactor core can be made smaller and more compact. Finally, the middle flux trap 9 in the core of the present invention is a high neutron flux region, which can provide an irradiation channel for irradiation tests. Since the nuclear reaction rate of the target placed in the irradiation channel is proportional to the number of neutrons absorbed per unit time, therefore, to complete an experiment in a short time, the higher the neutron flux of the reactor, the better. The middle flux trap 9 provides a high neutron flux, and setting it as an irradiation channel makes it fully utilized.

[0047] Therefore, the present invention can not only be used as a power reactor to output thermal energy, but also be used as a research reactor for fuel element irradiation tests, material irradiation tests, research and preparation of single crystal silicon neutron transmutation doping, etc. The lead-cooled fast reactor with this structure has good safety performance, compact structure and wide application fields, especially in future advanced industrial fields.

[0048] In some embodiments, due to the large density of the coolant lead, when the safety plate 7 or the regulating plate 4 inserts into the core, the buoyancy generated on it is also very large. Therefore, tungsten 21, a weight-bearing material, is added to the upper and lower parts of the safety plate 7 or the regulating plate 4.

[0049] The advantages of the present invention are: applying the plate-type fuel assembly commonly used in research reactors to lead-cooled fast reactors, which greatly enhances the overall heat transfer performance of the reactor and is beneficial to the miniaturization development of lead-cooled fast reactors; adopting a dual control system with internal and external control plates to ensure the safety performance of the reactor; equipping a lead-cooled fast reactor with an irradiation channel, increasing the uses of the reactor and bringing additional economic benefits.

[0050] Taking the core design of an advanced industrial nuclear reactor as an example, a compact high-flux small multi-purpose lead-cooled fast reactor provided by the present invention can, on the one hand, provide the thermal energy required for production to meet the electricity demand, and on the other hand, can use the irradiation channel for research such as material testing, bringing additional benefits.

[0051] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. A structurally compact high-throughput small multi-purpose lead-cooled fast reactor, characterized in that, It includes an outer containment and an inner containment. The outer containment and the inner containment enclose to form a chamber. The middle part of the inner containment is hollow to form a flux trap. An inner fuel zone and an outer fuel zone are arranged in sequence from inside to outside in the chamber. Fuel assemblies are arranged in both the inner fuel zone and the outer fuel zone. A safety plate is movably arranged between the inner fuel zone and the inner containment. A plurality of regulating plates are movably arranged between the outer containment and the outer fuel zone. Each of the regulating plates is arranged circumferentially along the outer fuel zone and can move independently. The safety plate and the regulating plates are used to insert or withdraw along the axial direction of the lead-cooled fast reactor. Both the inner fuel zone and the outer fuel zone communicate with the chamber. The chamber is used to fill with coolant lead. A reflector layer and a shielding layer are sequentially arranged on the outer peripheral side of the outer containment; Among them, the inner fuel zone is set to 4 inner fuel zone units. The fuel assemblies located in the inner fuel zone units are a number of arc-shaped plates arranged at intervals of 90° from inside to outside; the outer fuel zone is set to 8 outer fuel zone units. The fuel assemblies located in the outer fuel zone units are a number of arc-shaped plates arranged at intervals of 45° from inside to outside; cooling channels are formed between the arc-shaped plates. The number of the regulating plates is 8; Heavy material tungsten is installed on the upper and lower parts of the safety plate or the regulating plates; 8 guide rails are arranged on the inner side of the outer containment. Both sides of each guide rail have guide grooves. The regulating plates are slidably arranged on the guide rails.

2. The structurally compact high-throughput small multi-purpose lead-cooled fast reactor according to claim 1, characterized in that: The enrichment degrees of uranium-235 in the inner fuel zone and the outer fuel zone are set differently.

3. The structurally compact high-throughput small multi-purpose lead-cooled fast reactor according to claim 1, characterized in that: A sleeve is arranged on the outer side of the inner containment. The sleeve is hollow. The safety plate reciprocally moves along the hollow part of the sleeve.

4. The structurally compact high-throughput small multi-purpose lead-cooled fast reactor according to claim 1, characterized in that: The arc-shaped plate includes a fuel cladding. Fuel pellets are filled in the middle of the fuel cladding. Fission gas cavities and reflector parts are symmetrically arranged at both ends of the fuel pellets along the axial direction in sequence.

5. The structurally compact high-throughput small multi-purpose lead-cooled fast reactor according to claim 1, characterized in that: Both the safety plate and the regulating plates include a control plate cladding. Boron carbide as an absorption material is filled in the middle of the control plate cladding, and tungsten as a metal material is filled at both ends.

6. The structurally compact high-throughput small multi-purpose lead-cooled fast reactor according to claim 1, characterized in that: A positioning grid is arranged in the chamber. The positioning grid is fixedly installed on the inner side of the outer containment and the outer side of the inner containment. The positioning grid includes side plates for separating the fuel zones. Both side parts of the arc-shaped plate are fixedly connected to the side plates.

7. The structurally compact high-throughput small multi-purpose lead-cooled fast reactor according to claim 6, characterized in that: Non-fuel sections are arranged on both side parts of the arc-shaped plate. The arc-shaped plate is connected to the side plates through the non-fuel sections.

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