Core arrangement and component arrangement of a metal-cooled reactor containing a solid moderator

Abstract

The present invention belongs to the technical field of nuclear reactor design, and specifically relates to a core arrangement and component arrangement of a metal-cooled reactor containing a solid moderator, comprising: a core active region of a hexagonal structure, a shroud arranged on the outer layer of the core active region, a coolant arranged between the inner layer of the shroud and the outer layer of the core active region, and a plurality of fuel rods and poison materials arranged inside the core active region; the poison material has a thermal neutron absorption peak in the range of 0.1ev to 1ev. The core arrangement and fuel component arrangement of a metal-cooled reactor containing a solid moderator designed by the present invention can enhance the negative feedback of the core temperature of the metal-cooled reactor containing a solid moderator and ensure the safety of the core of the metal-cooled reactor.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear reactor design, and in particular relates to a core arrangement and component arrangement of a metal-cooled reactor containing a solid moderator. Background Art

[0002] Metal-cooled reactors use media such as sodium, lead or lead-bismuth alloy as coolant. Compared with traditional pressurized water reactors that use water as coolant, metal coolants have the characteristics of weak neutron slowing down and stable properties, which makes metal-cooled reactors have excellent neutron physics, thermal hydraulics and system safety properties.

[0003] In order to enhance the core moderation, the core design of the metal-cooled reactor is usually carried out by loading solid moderator rods or by digging holes in the solid moderator matrix to arrange the fuel rods. However, the hydrogen atoms in the solid moderator are in the crystal and are more likely to be in an excited state. When neutrons collide with hydrogen atoms in an excited state, if the neutron energy is low (especially <0.137ev), it is possible to obtain energy that is an integer multiple of 0.137ev. As the temperature of the solid moderator increases, the number of crystals in the excited state increases, thereby increasing the probability that thermal neutrons obtain quantized energy from the solid moderator crystals, making the neutron energy spectrum near the hot zone of the core harder, and increasing the number of thermal neutrons in the range of 0.1ev to 1ev. The absorption cross-section of most structural materials in the core in the low-energy neutron region conforms to the 1 / v law, while 235 There is a small resonance absorption peak in the range of 0.1ev to 1ev for U nuclides. Therefore, after the energy spectrum is hardened, the probability of neutrons leaving the moderator rod and being absorbed by the fuel rod increases, k eff Increases, the moderator temperature coefficient is small or even positive.

[0004] Therefore, it is necessary to design a core arrangement and fuel assembly arrangement of a metal-cooled reactor containing a solid moderator to enhance the negative feedback of the core temperature of the metal-cooled reactor containing a solid moderator and ensure the safety of the core of the metal-cooled reactor. Summary of the invention

[0005] The present invention aims at the prior art and proposes a core arrangement and component arrangement of a metal-cooled reactor containing a solid moderator, which is used to solve the technical problem that the temperature coefficient of the moderator in the core of the metal-cooled reactor loaded with a solid moderator is positive or too small, thereby improving the safety of the metal-cooled reactor.

[0006] The technical solution of the present invention:

[0007] A core arrangement of a metal-cooled reactor containing a solid moderator comprises: a core active region of a hexagonal structure, a shroud arranged at the outer layer of the core active region, a coolant arranged between the inner layer of the shroud and the outer layer of the core active region, and a plurality of fuel rods and poison materials arranged inside the core active region; the poison material has a thermal neutron absorption peak in the range of 0.1 eV to 1 eV.

[0008] The fuel rods are arranged in a hexagonal structure on the cross section inside the core active area. A poison rod is arranged at each of the six corners of the cross section of the core active area. The poison rod contains poison material with a thermal neutron absorption peak in the range of 0.1ev to 1ev.

[0009] The poison material in the poison rod includes Er and Er compounds; the radial size of the poison rod is consistent with the radial size of the fuel rod.

[0010] The fuel rod is provided with fuel core blocks, air gaps and fuel rod cladding in sequence from the inside to the outside, and the fuel rod cladding is provided with a poison coating on the outside. The poison coating contains poison material with a thermal neutron absorption peak in the range of 0.1ev to 1ev.

[0011] The poison material contained in the poison coating includes: Er and Er compounds; the thickness of the poison coating is 40 μm or 80 μm.

[0012] The inner layer of the enclosure is coated with a core poison coating layer; the core poison coating layer contains poison materials with a thermal neutron absorption peak in the range of 0.1ev to 1ev.

[0013] The poison materials contained in the core poison coating layer include: Er and Er compounds; the thickness of the core poison coating layer is 0.5 mm.

[0014] The interior of the fuel rod is sequentially surrounded by a mixed poison fuel pellet, an air gap and a fuel rod cladding from the inside to the outside; the mixed poison fuel pellet contains a poison material and a fuel material having a thermal neutron absorption peak in the range of 0.1ev to 1ev, and the poison material and the fuel material are uniformly mixed; the mass fraction of the poison material is 1.5%.

[0015] The poison material in the mixed poison fuel pellets includes Er and Er compounds.

[0016] The interior of the fuel rod includes: dispersed poison particles and fuel material. The dispersed poison particles are poison materials with thermal neutron absorption peaks in the range of 0.1ev to 1ev, and the poison materials and fuel materials are uniformly mixed. The mass fraction of the poison materials in the fuel rod is 1.5%.

[0017] A component arrangement of a metal-cooled reactor containing a solid moderator comprises a core active region of a hexagonal structure, a plurality of fuel assemblies and a plurality of moderator assemblies arranged inside the core active region, wherein one of the fuel assemblies is arranged at the center of the core active region, that is, the fuel assembly is arranged concentrically and coaxially with the core active region, and the remaining fuel assemblies and moderator assemblies are arranged from the inside to the outside inside the core active region around the fuel assembly.

[0018] One of the fuel assemblies is arranged at the center of the core active region, and the remaining fuel assemblies and moderator assemblies are arranged alternately around the fuel assembly from the inside to the outside of the core active region in a single-layer cross-section hexagonal shape;

[0019] The number of the fuel assemblies arranged in a single-layer hexagonal cross section is 36, which are arranged in two layers in the core active area; the number of the first layer of fuel assemblies is 12, and the number of the second layer of fuel rod assemblies is 12;

[0020] The number of the moderator rod assemblies arranged in a single-layer hexagonal cross-section is 54, which are arranged in three layers in the core active area. The number of moderator rod assemblies in the first layer is 6, the number of moderator rod assemblies in the second layer is 18, and the number of moderator rod assemblies in the third layer is 30.

[0021] One of the fuel assemblies is arranged at the center of the core active area, that is, the fuel assembly 100 is arranged concentrically and coaxially with the core active area, and the remaining fuel assemblies and moderator assemblies are arranged alternately around the fuel assembly from the inside to the outside of the core active area in accordance with a single-layer cross-section hexagonal shape;

[0022] The number of the fuel assemblies arranged in a hexagonal cross section is 24 in total, and they are arranged in two layers. The number of the fuel assemblies in the first layer is 12, and each fuel assembly 100 is arranged adjacent to each other; the number of the fuel assemblies in the second layer is 12;

[0023] There are 54 moderator assemblies arranged in a hexagonal cross section, which are arranged in four layers. The first layer has 6 moderator assemblies, the second layer has 18 moderator assemblies, and the third layer has 12 moderator assemblies. A second-layer fuel assembly is also arranged between each moderator assembly in the third layer. The fourth layer has 18 moderator assemblies, and a fuel assembly is respectively arranged on both sides of two adjacent moderator assemblies in the middle of the same side of the fourth layer.

[0024] One of the fuel assemblies is arranged at the center of the core active area, and the number of moderator assemblies arranged around the fuel assembly is 18, and the 18 moderator assemblies are arranged in a double-layer cross-section hexagonal shape;

[0025] Around the 18 moderator assemblies, the remaining fuel assemblies and the remaining moderator assemblies are alternately arranged from the inside to the outside of the core active area in a single-layer cross-section hexagonal shape;

[0026] The number of the fuel assemblies arranged in a single-layer hexagonal cross section is 90, which are arranged in three layers in the core active area; the number of the first layer of fuel assemblies is 18, the number of the second layer of fuel assemblies is 30, and the number of the third layer of fuel assemblies is 42;

[0027] The number of the moderator rod assemblies arranged in a single-layer hexagonal cross section is 108, which are arranged in three layers in the core active area, with the number of the moderator rod assemblies in the first layer being 24, the number of the moderator rod assemblies in the second layer being 36, and the number of the moderator rod assemblies in the third layer being 48;

[0028] The total number of layers of the fuel assemblies and moderator assemblies arranged in a hexagonal cross-section is greater than or equal to seven.

[0029] The fuel assembly contains the poison material having a thermal neutron absorption peak in the range of 0.1 ev to 1 ev, wherein the poison material is Er2O3, and the mass fraction of the poison material in the fuel assembly is 0.5%.

[0030] The surface of the fuel assembly is coated with the above-mentioned poison material having a thermal neutron absorption peak in the range of 0.1ev to 1ev, the coating thickness of the poison material is 0.01mm, and the poison material is Er2O3.

[0031] Beneficial effects of the present invention:

[0032] The core arrangement and component arrangement of a metal-cooled reactor containing a solid moderator described in the present invention, wherein the core arrangement method is to select a poison material with a thermal neutron absorption peak in the range of 0.1ev to 1ev to absorb thermal neutrons that are not absorbed by the moderator rods due to the increase in temperature; another component arrangement method is to perform a special geometric arrangement of the fuel components in the metal-cooled reactor containing a solid moderator to reduce the probability of thermal neutrons that are not absorbed by the moderator rods due to the increase in temperature entering the fuel rods. Both of the above methods can effectively enhance the negative feedback of the core temperature of the metal-cooled reactor containing a solid moderator and improve the safety of the metal-cooled reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the core arrangement for the arrangement of poison rods in a metal-cooled reactor with a solid moderator;

[0034] Figure 2 A schematic diagram of poison coating on the outside of a fuel rod in a metal-cooled reactor containing a solid moderator;

[0035] Figure 3 A schematic diagram of a poison coating in the coaming of a metal-cooled reactor containing a solid moderator;

[0036] Figure 4 The schematic diagram is a structural diagram of a fuel rod containing mixed poison fuel pellets arranged in a metal-cooled reactor containing a solid moderator;

[0037] Figure 5 The present invention is a schematic diagram of the structure of fuel rods containing diffuse poison particles arranged in a metal-cooled reactor containing a solid moderator.

[0038] Figure 6 Schematic diagram of the assembly layout of fuel rods and moderator rods arranged in layers in a metal-cooled reactor with a solid moderator

[0039] Figure 7 Schematic diagram of the assembly layout of fuel rods and moderator rods in a "hexagonal star" shape in a metal-cooled reactor with a solid moderator

[0040] Figure 8 A schematic diagram of the assembly layout of densely arranged fuel rods and moderator rods in a metal-cooled reactor containing a solid moderator.

[0041] Among them: 1-fuel rod, 2-poison rod, 3-fuel cladding, 4-air gap, 5-fuel pellet, 6-poison coating, 7-surrounding plate, 8-core active area, 9-coolant, 10-core poison coating, 11-mixed poison fuel pellet, 12-dispersed poison particles, 100-fuel assembly, 200-moderator assembly DETAILED DESCRIPTION

[0042] The core arrangement and component arrangement of a metal-cooled reactor containing a solid moderator according to the present invention are described in detail below in conjunction with the accompanying drawings and embodiments.

[0043] A core arrangement of a metal-cooled reactor containing a solid moderator comprises: a core active region 8 of a hexagonal structure, a shroud 7 arranged on the outer layer of the core active region 8, a coolant 9 arranged between the inner layer of the shroud 7 and the outer layer of the core active region 8, a plurality of fuel rods 1 and poison materials arranged inside the core active region 8; the poison materials have a thermal neutron absorption peak in the range of 0.1 eV to 1 eV.

[0044] The fuel rods 1 are arranged in a hexagonal structure on the cross section inside the core active area 8. A poison rod 2 is arranged at each of the six corners of the cross section of the core active area 8. The poison rod 2 contains a poison material with a thermal neutron absorption peak in the range of 0.1ev to 1ev.

[0045] The poison material in the poison rod 2 includes Er and Er compounds; the radial dimension of the poison rod 2 is consistent with the radial dimension of the fuel rod 1.

[0046] The interior of the fuel rod 1 is surrounded by fuel pellets 5, air gaps 4 and fuel rod cladding 3 in sequence from the inside to the outside. The exterior of the fuel rod cladding 3 is provided with a poison coating 6, which contains a poison material having a thermal neutron absorption peak in the range of 0.1ev to 1ev.

[0047] The poison material contained in the poison coating 6 includes Er and Er compounds; the thickness of the poison coating 6 is 40 μm or 80 μm.

[0048] The inner layer of the enclosure 7 is coated with a core poison coating layer 10; the core poison coating layer 10 contains a poison material having a thermal neutron absorption peak in the range of 0.1 ev to 1 ev.

[0049] The poison material contained in the core poison coating layer 10 includes Er and Er compounds; the thickness of the core poison coating layer 10 is 0.5 mm.

[0050] The fuel rod 1 is provided with a mixed poison fuel pellet 11, an air gap 4 and a fuel rod cladding 3 in sequence from the inside to the outside; the mixed poison fuel pellet 11 contains a poison material and a fuel material having a thermal neutron absorption peak in the range of 0.1ev to 1ev, and the poison material and the fuel material are uniformly mixed; the mass fraction of the poison material is 1.5%.

[0051] The poison material in the mixed poison fuel pellet 11 includes Er and Er compounds.

[0052] The fuel rod 1 includes: dispersed poison particles 12 and fuel material. The dispersed poison particles 12 are poison materials with thermal neutron absorption peaks in the range of 0.1ev to 1ev, and the poison materials are uniformly mixed with the fuel materials. The mass fraction of the poison materials in the fuel rod 1 is 1.5%.

[0053] By selecting poison materials with thermal neutron absorption peaks in the range of 0.1 ev to 1 ev, including but not limited to Er (erbium) and Er compounds, the thermal neutron absorption capability after the energy spectrum hardening caused by the increase in temperature of the solid moderator is enhanced.

[0054] When the reactor is operating normally, the core is fully moderated, the energy spectrum is thermal, the neutron absorption capacity of the poison material is small, and the poison material has little effect on the reactor reactivity; when the moderator temperature rises, the neutron energy spectrum hardens, the number of neutrons in the range of 0.1ev to 1ev increases, and the neutron absorption capacity of the poison material is enhanced, thereby introducing greater negative reactivity and enhancing the negative feedback of the core moderator temperature.

[0055] In summary, the core temperature negative feedback of the metal-cooled reactor with solid moderator can be enhanced by selecting the following five methods or any combination of the five methods for core arrangement:

[0056] Method 1: placing a poison material having a thermal neutron absorption peak in the range of 0.1 ev to 1 ev in the poison rod, including but not limited to making the poison material into a rod-shaped element to replace part of the fuel rods and arranging it in the fuel assembly;

[0057] Method 2: Setting a poison material with a thermal neutron absorption peak in the range of 0.1ev to 1ev as a fuel rod poison coating, including but not limited to uniformly applying a layer of poison material inside / outside the fuel rod cladding and inside / outside the fuel pellet;

[0058] Method 3: Setting a poison material with a thermal neutron absorption peak in the range of 0.1ev to 1ev as a core poison coating layer, including but not limited to uniformly applying a layer of poison material on the inner layer of the core active area coaming;

[0059] Method 4: setting a poison material with a thermal neutron absorption peak in the range of 0.1ev to 1ev as a fuel rod uniformly mixed with poison, including but not limited to uniformly mixing a certain amount of poison material with fuel to make a fuel element with mixed poison;

[0060] Method 5: Setting poison materials with thermal neutron absorption peaks in the range of 0.1ev to 1ev as poison dispersed particles, including but not limited to dispersing a certain number of poison particles inside fuel rod cladding, moderator materials, grid materials, etc.

[0061] A component arrangement of a metal-cooled reactor containing a solid moderator includes a core active region 8 of a hexagonal structure, a plurality of fuel assemblies 100 and a plurality of moderator assemblies 200 arranged inside the core active region 8, wherein one of the fuel assemblies 100 is arranged at the center of the core active region 8, that is, the fuel assembly 100 is arranged concentrically and coaxially with the core active region 8, and the remaining fuel assemblies 100 and moderator assemblies 200 are arranged from the inside to the outside inside the core active region 8 around the fuel assembly 100.

[0062] Alternating ring layer assembly arrangement: one of the fuel assemblies 100 is arranged at the center of the core active area 8, and the remaining fuel assemblies 100 and moderator assemblies 200 are alternately arranged in a single-layer cross-sectional hexagonal pattern from the inside to the outside of the core active area 8 around the fuel assembly 100; the number of fuel assemblies 100 arranged in a single-layer cross-sectional hexagonal pattern is 36, which are arranged in two layers in the core active area 8; the number of fuel assemblies 100 in the first layer is 12, and the number of fuel rod assemblies 100 in the second layer is 12; the number of moderator rod assemblies 200 arranged in a single-layer cross-sectional hexagonal pattern is 54, which are arranged in three layers in the core active area 8, the number of moderator rod assemblies 200 in the first layer is 6, the number of moderator rod assemblies 200 in the second layer is 18, and the number of moderator rod assemblies 200 in the third layer is 30.

[0063] The components are arranged in the form of a "hexagonal star": one of the fuel assemblies 100 is arranged at the center of the core active area 8, that is, the fuel assembly 100 is arranged concentrically and coaxially with the core active area 8, and the remaining fuel assemblies 100 and moderator assemblies 200 are arranged alternately in a single-layer cross-sectional hexagonal shape from the inside to the outside of the core active area 8 around the fuel assembly 100; the number of the fuel assemblies 100 arranged in a hexagonal shape is 24 in total, and they are arranged in two layers. The number of fuel assemblies 100 in the first layer is 12, and each fuel assembly 100 is arranged adjacent to each other. The number of the moderator assemblies 200 in the second layer is 12; the number of the moderator assemblies 200 arranged in a hexagonal cross section is 54 in total, which are arranged in four layers, the number of the moderator assemblies 200 in the first layer is 6, the number of the moderator assemblies 200 in the second layer is 18, the number of the moderator assemblies 200 in the third layer is 12, and a second-layer fuel assembly 100 is further arranged between each moderator assemblies 200 in the third layer; the number of the moderator assemblies 200 in the fourth layer is 18, and a fuel assembly 100 is respectively arranged on both sides of two adjacent moderator assemblies 200 in the middle of the same side of the fourth layer.

[0064] Dense grid assembly arrangement: one of the fuel assemblies 100 is arranged at the center of the core active region 8, and the number of moderator assemblies 200 arranged around the fuel assembly 100 is 18, and the above-mentioned 18 moderator assemblies 200 are arranged in a double-layer cross-section hexagonal arrangement; around the 18 moderator assemblies 200, the remaining fuel assemblies 100 and the remaining moderator assemblies 200 are arranged alternately in single-layer cross-section hexagons from the inside to the outside of the core active region 8; the number of the fuel assemblies 100 arranged in single-layer cross-section hexagons is 90, which are arranged in three layers in the core active region 8. zone 8; the number of fuel assemblies 100 in the first layer is 18, the number of fuel assemblies 100 in the second layer is 30, and the number of fuel assemblies 100 in the third layer is 42; the number of moderator rod assemblies 200 arranged in a single-layer hexagonal cross-section is 108, which are arranged in three layers in the core active zone 8, the number of moderator rod assemblies 200 in the first layer is 24, the number of moderator rod assemblies 200 in the second layer is 36, and the number of moderator rod assemblies 200 in the third layer is 48; the total number of layers of fuel assemblies 100 and moderator assemblies 200 arranged in a hexagonal cross-section is greater than or equal to seven layers.

[0065] The fuel assembly 100 with alternating ring arrangement, "hexagonal star" arrangement or dense grid arrangement contains the above-mentioned poison material with a thermal neutron absorption peak in the range of 0.1ev to 1ev. The poison material is Er2O3, and the mass fraction of the poison material in the fuel assembly is 0.5%.

[0066] The surface of the fuel assembly 100 is coated with the poison material having a thermal neutron absorption peak in the range of 0.1 ev to 1 ev. The coating thickness of the poison material is 0.01 mm, and the poison material is Er2O3.

[0067] In summary, the above-mentioned component arrangement of the metal-cooled reactor containing a solid moderator adopts the following three methods or any combination of the three methods to arrange the fuel assemblies and the moderator assemblies in the assembly.

[0068] Assembly arrangement mode 1: The fuel assemblies 100 and the moderator assemblies 200 are arranged in alternating layers or in a "six-pointed star" form in the core active region 8;

[0069] Assembly arrangement mode 2: The fuel assemblies 100 and the moderator assemblies 200 are arranged in a dense grid distribution in the reactor active region 8 .

[0070] Component arrangement method three: Add poison materials with thermal neutron absorption peaks in the range of 0.1ev to 1ev described in any of the five core arrangements mentioned above to the fuel assemblies in the above two component arrangements, and by combining the above three methods, a more significant solid moderator temperature negative feedback can be obtained than with a single method.

[0071] Through the special arrangement of fuel assemblies and moderator assemblies, the fuel assemblies and moderator assemblies in the core are staggered as evenly as possible. In this kind of core with special geometric arrangement, the increase of moderator temperature will not only make the neutron spectrum at the moderator rod harden, but also make the fuel rod spectrum around the moderator rod harden, thereby reducing the probability of thermal neutrons not absorbed by the moderator rod being absorbed by the fuel rod when the temperature rises, thereby reducing the positive feedback caused by the core moderator temperature.

[0072] Example 1

[0073] For reactors using lead-bismuth alloy as coolant, the moderator temperature coefficient is positive: when all rods are withdrawn, the moderator temperature coefficient is 2.76 pcm / ℃, and when all rods are inserted, the moderator temperature coefficient is 1.45 pcm / ℃. Figure 1 As shown, the fuel rods 1 are arranged in a hexagonal structure on the cross section inside the core active area 8. A poison rod 2 is arranged at each of the six corners of the cross section of the core active area 8. The poison rod 2 contains a poison material with a thermal neutron absorption peak in the range of 0.1ev to 1ev. The poison rod 2 uses Er as the poison material. The radial size structure of the poison rod 2 is consistent with that of the fuel rod 1. The moderator temperature coefficient is -0.96pcm / ℃ when all rods are withdrawn, and the moderator temperature coefficient is -1.77pcm / ℃ when all rods are inserted. The safety of the core is guaranteed.

[0074] Example 2

[0075] Different from Example 1, Figure 2 As shown, the fuel rod 1 is surrounded by fuel pellets 5, air gaps 4 and fuel rod cladding 3 from the inside to the outside, and the fuel rod cladding 3 is provided with a poison coating 6 on the outside. The poison coating 6 contains a poison material having a thermal neutron absorption peak in the range of 0.1ev to 1ev. The poison material is Er, and the thickness of the poison coating 6 is 40μm or 80μm. After the outside of the fuel rod cladding 3 is evenly coated with a 40μm or 80μm poison material Er coating, the moderator temperature coefficient is -1.07pcm / ℃ when the rods are fully withdrawn, and the moderator temperature coefficient is -2.11pcm / ℃ when the rods are fully inserted. The safety of the core is guaranteed.

[0076] Example 3

[0077] The difference between implementation 1 and implementation 2 is that Figure 3As shown, the inner layer of the enclosure 7 disposed on the outer layer of the core active region 8 is coated with a core poison coating layer 10; the core poison coating layer 10 contains a poison material having a thermal neutron absorption peak in the range of 0.1ev to 1ev. The poison material contained in the core poison coating layer 10 is Er, and the thickness of the core poison coating layer 10 is 0.5mm.

[0078] For a reactor using lead-bismuth alloy as coolant, the moderator temperature coefficient is positive, 2.76pcm / ℃ when all rods are withdrawn, and 1.45pcm / ℃ when all rods are inserted. After evenly applying 0.5mm thick poison material Er on the inner layer of the core active area enclosure 7, the moderator temperature coefficient is -0.52pcm / ℃ when all rods are withdrawn, and -1.33pcm / ℃ when all rods are inserted. The safety of the core is guaranteed.

[0079] Example 4

[0080] For a reactor using lead-bismuth alloy as coolant, the moderator temperature coefficient is positive: the moderator temperature coefficient is 2.76pcm / ℃ when all rods are withdrawn, and the moderator temperature coefficient is 1.45pcm / ℃ when all rods are inserted.

[0081] like Figure 4 As shown, the interior of the fuel rod 1 is sequentially surrounded by a mixed poison fuel pellet 11, an air gap 4 and a fuel rod cladding 3 from the inside to the outside; the mixed poison fuel pellet 11 contains a poison material and a fuel material having a thermal neutron absorption peak in the range of 0.1ev to 1ev, and the poison material and the fuel material are uniformly mixed; the mass fraction of the poison material is 1.5%.

[0082] use Figure 4 The fuel rod core block setting is as follows: the moderator temperature coefficient is -4.73pcm / ℃ when all rods are withdrawn, and the moderator temperature coefficient is -6.64pcm / ℃ when all rods are inserted, which ensures the safety of the core.

[0083] Example 5

[0084] For a reactor using lead-bismuth alloy as coolant, the moderator temperature coefficient is positive: the moderator temperature coefficient is 2.76pcm / ℃ when all rods are withdrawn, and the moderator temperature coefficient is 1.45pcm / ℃ when all rods are inserted.

[0085] like Figure 5 As shown, dispersed poison particles 12 and fuel materials are uniformly arranged inside the fuel rod 1, the dispersed poison particles 12 are poison materials with thermal neutron absorption peaks in the range of 0.1ev to 1ev, and the poison materials and fuel materials are uniformly mixed; the mass fraction of the poison materials in the fuel rod 1 is 1.5%.

[0086] The uniformly dispersed poison material in the dispersed poison particles 12 is Er, of which the mass fraction of Er is 1.5%. When the core is arranged using the dispersed poison particles 12 structure, the moderator temperature coefficient is -1.38pcm / ℃ when all rods are withdrawn, and the moderator temperature coefficient is -2.93pcm / ℃ when all rods are inserted.

[0087] Example 6

[0088] For a reactor using lead-bismuth alloy as coolant, the fuel assembly 100 and the moderator assembly 200 are arranged in a centralized manner in the core active region 8, and the moderator temperature coefficient is 6.52 pcm / °C. Figure 6 When the fuel assembly 100 and the moderator assembly 200 are arranged in a ring layer, the moderator temperature coefficient is 1.23 pcm / °C, and the moderator temperature coefficient is significantly reduced.

[0089] Example 7

[0090] For a reactor using lead-bismuth alloy as coolant, the fuel assembly 100 and the moderator assembly 200 in the core active region 8 are arranged in a centralized manner, and the moderator temperature coefficient is 6.52 pcm / °C. Figure 7 When the "hexagonal star" structure is arranged as shown, the moderator temperature coefficient is 0.64pcm / ℃, and the moderator temperature coefficient is significantly reduced.

[0091] Example 8

[0092] For a reactor using lead-bismuth alloy as coolant, if the fuel assemblies 100 and the moderator assemblies 200 in the core active region 8 are arranged in a concentrated manner, the moderator temperature coefficient is 6.52 pcm / °C. Figure 7 After the "hexagonal star" structure is arranged as shown and the Er2O3 poison with a mass fraction of 0.5% is uniformly mixed in the fuel assembly 100, the moderator temperature coefficient is 0.006pcm / °C, and the moderator temperature coefficient is significantly reduced.

[0093] Example 9

[0094] For a reactor using lead-bismuth alloy as coolant, if the fuel assemblies 100 and the moderator assemblies 200 in the core active region 8 are arranged in a centralized manner, the moderator temperature coefficient is 6.52 pcm / °C. Figure 7 After the "hexagonal star" structure is arranged and the outer part of the fuel assembly 100 is coated with a 0.01 mm thick Er2O3 poison coating, the moderator temperature coefficient is 0.38 pcm / °C, and the moderator temperature coefficient is significantly reduced.

[0095] Example 10

[0096] For a reactor using lead-bismuth alloy as coolant, if the fuel assembly 100 and the moderator assembly 200 in the core active region 8 are arranged in a common grid, the moderator temperature coefficient is 1.23 pcm / °C. Figure 8 When the dense grid arrangement is shown, the moderator temperature coefficient is 0.07pcm / ℃, and the moderator temperature coefficient is significantly reduced. The size of the fuel assembly with dense grid arrangement is consistent with the size of the fuel assembly with ordinary grid arrangement;

[0097] The embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the field without departing from the purpose of the present invention.

Claims

1. A core arrangement of a metal-cooled reactor containing a solid moderator, characterized in that: The core arrangement of a solid moderator metal-cooled reactor comprises: a core active region (8) of a hexagonal structure, a shroud (7) arranged at the outer layer of the core active region (8), a coolant (9) arranged between the inner layer of the shroud (7) and the outer layer of the core active region (8), a plurality of fuel rods (1) and a poison material arranged inside the core active region (8); the poison material has a thermal neutron absorption peak in the range of 0.1 eV to 1 eV; The fuel rods (1) are arranged in a hexagonal structure on the cross section inside the core active region (8), and a poison rod (2) is arranged at each of the six corners of the cross section of the core active region (8). The poison rods (2) contain a poison material having a thermal neutron absorption peak in the range of 0.1 eV to 1 eV. The poison material in the poison rod (2) includes Er and a compound of Er; the radial dimension of the poison rod (2) is consistent with the radial dimension of the fuel rod (1); The interior of the fuel rod (1) is provided with fuel pellets (5), an air gap (4) and a fuel rod cladding (3) in sequence from the inside to the outside, and the exterior of the fuel rod cladding (3) is provided with a poison coating (6), wherein the poison coating (6) contains a poison material having a thermal neutron absorption peak in the range of 0.1 eV to 1 eV; The poison material contained in the poison coating (6) includes: Er and Er compounds; the thickness of the poison coating (6) is 40 μm or 80 μm; The inner layer of the enclosure (7) is coated with a core poison coating layer (10); the core poison coating layer (10) contains a poison material having a thermal neutron absorption peak in the range of 0.1 eV to 1 eV; The poison material contained in the core poison coating layer (10) includes: Er and Er compounds; the thickness of the core poison coating layer (10) is 0.5 mm; The fuel rod (1) is provided with a mixed poison fuel pellet (11), an air gap (4) and a fuel rod cladding (3) in an annular manner from the inside to the outside. The mixed poison fuel pellet (11) contains a poison material having a thermal neutron absorption peak in the range of 0.1 eV to 1 eV and a fuel material, and the poison material and the fuel material are uniformly mixed. The mass fraction of the poison material is 1.5%. The poison material in the mixed poison fuel pellet (11) includes: Er and Er compounds; The fuel rod (1) comprises: dispersed poison particles (12) and fuel material, the dispersed poison particles (12) are poison materials having a thermal neutron absorption peak in the range of 0.1 eV to 1 eV, and the poison material and the fuel material are uniformly mixed; the mass fraction of the poison material in the fuel rod (1) is 1.5%; The invention also comprises a plurality of fuel assemblies (100) and a plurality of moderator assemblies (200) arranged inside the core active region (8), wherein one of the fuel assemblies (100) is arranged at the center of the core active region (8), that is, the fuel assembly (100) is arranged concentrically and coaxially with the core active region (8), and the remaining fuel assemblies (100) and moderator assemblies (200) are arranged from the inside to the outside inside the core active region (8) around the fuel assembly (100).

2. The core arrangement of a metal-cooled reactor containing a solid moderator according to claim 1, characterized in that: One of the fuel assemblies (100) is arranged at the center of the core active region (8), and the remaining fuel assemblies (100) and moderator assemblies (200) are alternately arranged around the fuel assembly (100) in the core active region (8) from the inside to the outside in accordance with a single-layer cross-section hexagonal shape; The number of the fuel assemblies (100) arranged in a single-layer hexagonal cross-section is 36, which are arranged in two layers in the core active area (8); the number of the first layer of fuel assemblies (100) is 12, and the number of the second layer of fuel assemblies (100) is 12; The number of the moderator assemblies (200) arranged in a single-layer hexagonal cross-section is 54, which are arranged in three layers in the core active area (8), the number of the moderator assemblies (200) in the first layer is 6, the number of the moderator assemblies (200) in the second layer is 18, and the number of the moderator assemblies (200) in the third layer is 30.

3. The core arrangement of a metal-cooled reactor containing a solid moderator according to claim 2, characterized in that: One of the fuel assemblies (100) is arranged at the center of the core active region (8), that is, the fuel assembly (100) is arranged concentrically and coaxially with the core active region (8), and the remaining fuel assemblies (100) and moderator assemblies (200) are arranged alternately around the fuel assembly (100) in the core active region (8) from the inside to the outside in accordance with a single-layer cross-section hexagonal shape; The number of fuel assemblies (100) arranged in a hexagonal cross section is 24 in total, and they are arranged in two layers. The number of fuel assemblies (100) in the first layer is 12, and each fuel assembly (100) is arranged adjacent to each other; the number of fuel assemblies (100) in the second layer is 12; There are 54 moderator assemblies (200) arranged in a hexagonal cross section, which are arranged in four layers. The first layer has 6 moderator assemblies (200), the second layer has 18 moderator assemblies (200), and the third layer has 12 moderator assemblies (200). A second layer fuel assembly (100) is also arranged between each moderator assembly (200) in the third layer. The fourth layer has 18 moderator assemblies (200), and a fuel assembly (100) is respectively arranged on both sides of two adjacent moderator assemblies (200) in the middle of the same side of the fourth layer.

4. The core arrangement of a metal-cooled reactor containing a solid moderator according to claim 3, characterized in that: One of the fuel assemblies (100) is arranged at the center of a core active region (8), and the number of moderator assemblies (200) arranged around the fuel assembly (100) is 18, and the 18 moderator assemblies (200) are arranged in a double-layer cross-section hexagonal shape; Surrounding the 18 moderator assemblies (200), the remaining fuel assemblies (100) and the remaining moderator assemblies (200) are alternately arranged from the inside to the outside of the core active region (8) in a single-layer cross-section hexagonal shape; The number of the fuel assemblies (100) arranged in a single-layer hexagonal cross-section is 90, which are arranged in three layers in the core active area (8); the number of the fuel assemblies (100) in the first layer is 18, the number of the fuel assemblies (100) in the second layer is 30, and the number of the fuel assemblies (100) in the third layer is 42; The number of the moderator assemblies (200) arranged in a single-layer hexagonal cross-section is 108, which are arranged in three layers in the core active area (8), the number of the moderator assemblies (200) in the first layer is 24, the number of the moderator assemblies (200) in the second layer is 36, and the number of the moderator assemblies (200) in the third layer is 48; The total number of layers of fuel assemblies (100) and moderator assemblies (200) arranged in a hexagonal cross section is greater than or equal to seven layers.

5. The core arrangement of a metal-cooled reactor containing a solid moderator according to claim 4, characterized in that: The fuel assembly (100) contains the poison material having a thermal neutron absorption peak in the range of 0.1 ev to 1 ev as described in claim 1, wherein the poison material is Er2O3, and the mass fraction of the poison material in the fuel assembly is 0.5%.

6. The core arrangement of a metal-cooled reactor containing a solid moderator according to claim 5, characterized in that: The surface of the fuel assembly (100) is coated with the poison material having a thermal neutron absorption peak in the range of 0.1 ev to 1 ev as claimed in claim 1, the coating thickness of the poison material is 0.01 mm, and the poison material is Er2O3.

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