Spectral shift burnable poison rod-containing reactor core adopting thermal neutron trap design
By combining thermal neutron trap design with spectral shift combustible poison rods in the reactor core, effective control of residual reactivity and reduction of poison residues were achieved, optimizing core reactivity control and fuel utilization, and improving core safety and economy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-15
- Publication Date
- 2026-03-13
AI Technical Summary
After the introduction of moderator materials into the core of a conventional reactor, the proportion of thermal neutrons in the core increases, leading to increased residual reactivity, a heavier operating burden on the control rods, and a high level of end-of-life poison residue, making it difficult to achieve effective reactivity control and burnup matching.
The reactor employs a thermal neutron trap design, combined with radially partitioned arrangement of low-enrichment and high-enrichment fuel assemblies, and introduces spectral-shifted combustible poison rods into the core. Local thermal neutron traps are formed using metal hydrides, and thermal neutrons are absorbed by combustible poison materials. Combined with lead-bismuth coolant and core designs with different B-10 enrichment, reactivity control and burnup matching are achieved.
It effectively suppressed the residual reactivity in the early stage of the reactor core, reduced the residual poison at the end of the reactor life, optimized the core power distribution and reactivity control, improved neutron economy and fuel utilization efficiency, and ensured the compactness and safety of the reactor core.
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Figure CN121662436A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nuclear reactor core technology, and more specifically to a reactor core with spectral shift combustible poison rods designed using a thermal neutron trap. Background Technology
[0002] The neutron spectrum characteristics of a nuclear reactor core are one of the key factors affecting its physical design and safe operation. Based on the content of moderator material in the active region of the core and the hardness of the neutron spectrum, reactor cores can generally be divided into three categories: fast neutron spectrum, ultrathermal neutron spectrum, and thermal neutron spectrum. Traditional thermal neutron spectrum cores (such as pressurized water reactors) contain a large amount of moderator (such as water), have a high thermal neutron content, a large fission reaction cross section, and a relatively small critical mass. Fast neutron spectrum cores contain almost no moderator material, the neutrons are not sufficiently moderated, the energy spectrum is "harder", resulting in a smaller fission cross section for fissile nuclides, a larger core criticality, and limitations on economy and compactness.
[0003] To reduce the critical mass of a fast-spectrum reactor core while maintaining its excellent conversion ratio and fuel cycle characteristics, researchers have proposed a strategy of introducing solid moderators (such as metal hydrides) into the core. By appropriately softening the local energy spectrum, the probability of fission reactions can be increased, thereby reducing fuel loading requirements. However, the introduction of moderators also brings new problems: the increased proportion of thermal neutrons in the core may lead to increased residual reactivity, which places higher demands on reactivity control. Although traditional control rods can adjust reactivity, relying entirely on control rods will increase the operational burden and limit the core's operating margin and safety performance.
[0004] Against this backdrop, the concept of "spectrally shifted combustible poison rods" emerged. This design incorporates a certain amount of combustible poison material while introducing moderator materials. It utilizes the "thermal neutron trap" formed in the moderation region—that is, a region where the local thermal neutron density is significantly higher than the surrounding fast neutron environment—to allow the poison to preferentially absorb the moderated thermal neutrons, thereby effectively suppressing the residual reactivity in the early stages of the reactor core. As the reactor operates, the poison gradually "burns" due to the absorption of neutrons, resulting in a low residual amount at the end of its lifespan. The negative impact on the reactor core reactivity (i.e., reactivity penalty) is also reduced accordingly, achieving a match between reactivity control and the burnup process.
[0005] Traditional thermal neutron trap designs involve creating a specific region within the reactor core and using concentrated moderator materials to locally slow down fast neutrons into thermal neutrons, thus forming a thermal neutron enrichment zone. This is often used to improve fuel utilization efficiency or achieve specific physical experimental objectives, such as setting up a thermalized zone in a fast reactor to conduct material irradiation experiments. However, traditional thermal neutron traps do not systematically incorporate combustible poisons for reactivity control, nor are they optimized for "spectral shift" characteristics. Therefore, their ability to control residual reactivity and reduce end-of-life poison residue is limited.
[0006] Therefore, we propose a reactor core that can control the residual reactivity of the core and reduce the residue of poisons at the end of the core's life. Summary of the Invention
[0007] The purpose of this invention is to provide a reactor core with spectral shift combustible poison rods designed with a thermal neutron trap, which is used to solve the problems of controlling residual reactivity and reducing the ability to reduce end-of-life poison residue in conventional reactor core structures.
[0008] This invention is achieved through the following technical solution: A reactor core with spectral shift combustible poison rods using a thermal neutron trap design includes a low-enrichment fuel assembly with safety rods, a low-enrichment fuel assembly with regulation and compensation rods, a high-enrichment fuel assembly with regulation and compensation rods, and lead and bismuth. The low-enrichment fuel assembly containing safety rods and the low-enrichment fuel assembly containing adjustment and compensation rods are located at the center of the reactor core. The low-enrichment fuel assembly containing safety rods and the low-enrichment fuel assembly containing adjustment and compensation rods are surrounded by a high-enrichment fuel assembly containing adjustment and compensation rods. The high-enrichment fuel assembly containing adjustment and compensation rods is filled with lead-bismuth.
[0009] Furthermore, the fuel enrichment of the low-enrichment fuel assembly with safety rod and the low-enrichment fuel assembly with adjustment compensation rod is 17%, and the fuel enrichment of the high-enrichment fuel assembly with adjustment compensation rod is 19.75%.
[0010] Furthermore, the low-enrichment fuel assembly containing a safety rod has a structure consisting of, from the inside out, a safety rod, a fuel rod, a spectral-shifting combustible poison rod, an assembly box, and lead and bismuth.
[0011] Furthermore, the safety bar structure is formed from the inside out... It consists of a core, helium, a stainless steel cladding, air, control rods, guide rods, and lead-bismuth.
[0012] Furthermore, both the low-enrichment fuel assembly with regulating compensating rod and the high-enrichment fuel assembly with regulating compensating rod have a structure consisting of, from the inside out, a compensating rod, a fuel rod, a spectral shift combustible poison rod, an assembly box, and lead and bismuth.
[0013] Furthermore, the structure of the adjusting compensation rod consists of, from the inside out, a counterweight of tungsten, helium, a stainless steel cladding, and another helium gas. It consists of a core, helium gas, a stainless steel cladding, lead and bismuth, a control rod guide tube, and lead and bismuth.
[0014] Furthermore, the structure of the fuel rod consists of a fuel core, helium gas, a stainless steel cladding, and lead-bismuth from the inside out. The structure of the spectral shift combustible poison rod consists of spectral shift combustible poison material, helium gas, stainless steel cladding, and lead-bismuth from the inside out.
[0015] Furthermore, in the low-enrichment safety rod fuel assembly The core has a B-10 content of 90%, and the low enrichment includes the regulating compensating rod fuel assembly. The core has a B-10 content of 30%, and the high enrichment of the fuel assembly containing the regulating compensating rod is... The core contains 40% B-10.
[0016] Furthermore, the spectral shift flammable poison material is dispersed in a zirconium hydride matrix, wherein the mass percentage of the spectral shift flammable poison material in the low-enrichment fuel assembly with safety rod and the low-enrichment fuel assembly with adjustment compensation rod is 1%, and the mass percentage of the spectral shift flammable poison material in the high-enrichment fuel assembly with adjustment compensation rod is 1.2%.
[0017] Furthermore, the fuel type within the fuel core is... or .
[0018] The technical solution of the present invention has at least the following advantages and beneficial effects: This invention discloses a reactor core with spectral shift combustible poison rods designed with thermal neutron traps. By arranging spectral shift combustible poison rods containing metal hydride moderators and combustible poison materials in the core, strong thermal neutron traps are formed locally by the metal hydrides. This increases the absorption cross-section of the combustible poison for thermal neutrons at the beginning of its lifespan, thus requiring only a small amount of poison to effectively suppress residual reactivity. At the same time, the burnup rate of the poison in the thermal neutron traps is significantly accelerated, which can be well matched with the core burnup depth, greatly reducing poison residue and corresponding reactivity penalty at the end of the lifespan. This achieves smooth and automatic compensation for residual reactivity from the beginning to the end of the lifespan.
[0019] Furthermore, by employing a radial fuel enrichment zoning design, low-enrichment fuel assemblies are positioned at the core center, surrounded by high-enrichment fuel assemblies, and combined with lead-bismuth coolant, the core power distribution is effectively flattened. Simultaneously, different B-10 enrichment levels are used for different functional fuel assemblies. The core enables precise configuration and hierarchical control of the reactivity values of safety rods, compensation rods, and regulating rods, improving the control flexibility and safety of core operation while ensuring safety requirements such as shutdown depth and sticking rod criteria.
[0020] Furthermore, by radially partitioning the fuel enrichment and using different mass percentages of spectral shift combustible poison in different regions, the neutron economy and fuel utilization are optimized while ensuring reactivity control. This helps to reduce initial fuel requirements, increase core power density, make the core structure more compact, and significantly improve economic efficiency. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of a reactor core structure with spectral shift combustible poison rods designed using a thermal neutron trap according to the present invention; Figure 2 This is a schematic diagram of the structure of the fuel assembly containing the safety rod of the present invention; Figure 3 This is a schematic diagram of the fuel assembly with adjusting compensation rod of the present invention; Figure 4 This is a schematic diagram of the safety bar structure of the present invention; Figure 5 This is a schematic diagram of the fuel rod structure of the present invention; Figure 6 This is a schematic diagram of the adjusting compensation rod structure of the present invention; Figure 7 This is a schematic diagram of the combustible poison rod structure of the present invention.
[0022] Reference numerals: 1. Low-enrichment fuel assembly with safety rod; 2. Low-enrichment fuel assembly with regulating and compensating rod; 3. High-enrichment fuel assembly with regulating and compensating rod; 4. Lead-bismuth; 5. Safety rod; 6. Fuel rod; 7. Spectral-shifted flammable poison rod; 8. Assembly box; 9. Regulating and compensating rod; 10. 11. Core; 12. Helium; 13. Stainless steel cladding; 14. Air; 15. Control rod guide rod; 16. Tungsten counterweight; 17. Fuel core; 18. Combustible toxic material. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0024] Example 1 like Figure 1 As shown, a reactor core with spectral shift combustible poison rods using a thermal neutron trap design includes a low-enrichment fuel assembly with safety rods 1, a low-enrichment fuel assembly with regulating and compensating rods 2, a high-enrichment fuel assembly with regulating and compensating rods 3, and lead-bismuth 4. In addition, the fuel enrichment of the low-enrichment fuel assembly 1 with safety rod and the low-enrichment fuel assembly 2 with regulating compensating rod is 17%, and the fuel enrichment of the high-enrichment fuel assembly 3 with regulating compensating rod is 19.75%. This radial fuel enrichment zoning design aims to flatten the core power distribution. By using 17% low-enriched fuel in the central region, the power peak in the central region is effectively suppressed; while using 19.75% high-enriched fuel in the peripheral region compensates for reactivity losses caused by neutron leakage and improves the power level in the edge region. This zoning strategy, combined with the subsequent thermal neutron trap design, optimizes the overall core power distribution and reactivity control.
[0025] The low-enrichment fuel assembly 1 containing safety rods and the low-enrichment fuel assembly 2 containing adjustment and compensation rods are located at the center of the reactor core. The low-enrichment fuel assembly 1 containing safety rods and the low-enrichment fuel assembly 2 containing adjustment and compensation rods are surrounded by a high-enrichment fuel assembly 3 containing adjustment and compensation rods. The high-enrichment fuel assembly 3 containing adjustment and compensation rods is filled with lead-bismuth 4. This is a functionally defined and rationally zoned layout strategy. The central core region houses low-enrichment assemblies containing safety rods 5 and regulation / compensation rods 9, responsible for the main power output and rapid responsiveness regulation. The outermost high-enrichment assemblies containing compensation rods compensate for burnup and reactivity losses, improving neutron economy. The outermost lead-bismuth 4 layer not only serves as a coolant but also acts as a neutron reflector, reflecting leaked neutrons back to the core, improving neutron utilization and contributing to a compact core design.
[0026] This arrangement optimizes the core power distribution and meets safety requirements such as shutdown depth and sticking rod criteria, achieving flexibility in operation control. The core has a total of 19 fuel assemblies, including 4 low-enrichment fuel assemblies with safety rods, 3 low-enrichment fuel assemblies with conditioning rods, and 12 high-enrichment fuel assemblies with compensation rods.
[0027] Specifically, such as Figure 2 As shown, the low enrichment fuel assembly 1 containing a safety rod has a structure consisting of a safety rod 5, a fuel rod 6, a spectral shift combustible poison rod 7, an assembly box 8, and lead-bismuth 4 from the inside out. like Figure 3 As shown, the low-enrichment fuel assembly 2 with adjustment and compensation rod and the high-enrichment fuel assembly 3 with adjustment and compensation rod both have a structure consisting of, from the inside out, compensation rod, adjustment rod, fuel rod 6, spectral shift combustible poison rod 7, assembly box 8 and lead-bismuth 4. All fuel assemblies integrate spectral-shifting combustible poison rods 7. Fuel rods 6 provide fission reaction and power. The spectral-shifting combustible poison rods 7 utilize internal metal hydride moderators, such as zirconium hydride, to locally form thermal neutron traps, allowing the combustible poison to efficiently absorb thermal neutrons in this region. This controls residual reactivity at the beginning of its lifespan and reduces residual penalty through sufficient burn-off at the end of its lifespan. The assembly box 8 ensures the structural integrity of the assembly, while lead-bismuth 4 coolant flows between the rod bundles, carrying away fission heat.
[0028] like Figure 4 As shown, the safety bar 5 has a structure that is formed from the inside out. The reactor consists of a core 10, helium 11, stainless steel cladding 12, air 13, control rods and guide rods 14, and lead-bismuth 4; the safety rod 5 is a negative reactivity introduction device specifically designed for emergency shutdown, and its core... The core 10 has a high neutron absorption capacity. The air gap 13 in the guide tube serves as a coolant channel, effectively reducing resistance during control rod movement. This fuel assembly provides regional power while integrating a rapid shutdown function. In an emergency, the safety rod 5 is rapidly inserted into the core by gravity, and its significant reactivity value can quickly terminate the chain reaction.
[0029] like Figure 5 As shown, the structure of the adjusting compensation rod 9 consists of, from the inside out, a counterweight tungsten 15, helium gas 11, a stainless steel cladding 12, and helium gas 11. The fuel assembly consists of a core 10, helium gas 11, a stainless steel cladding 12, lead-bismuth gas 4, a control rod guide tube, and lead-bismuth gas 4. An adjustment and compensation rod 9 is used for precise daily reactivity control. A counterweight tungsten 15 balances buoyancy and gravity, ensuring the drive mechanism can accurately control its position. This fuel assembly achieves precise management of operational reactivity; the compensation rod is used for slow lifting to compensate for the decrease in reactivity caused by fuel consumption; the adjustment rod is used for fine-tuning to cope with power fluctuations. The complex structural design ensures the accuracy and safety of its operation.
[0030] like Figure 6 As shown, the structure of the fuel rod 6 consists of a fuel core 16, helium gas 11, stainless steel cladding 12, and lead-bismuth 4 from the inside out. like Figure 7 As shown, the structure of the spectral shift combustible poison rod 7 consists of spectral shift combustible poison material 17, helium gas 11, stainless steel shell 12, and lead-bismuth 4 from the inside out. like Figure 7As shown, fuel rod 6 and spectral-shifted combustible poison rod 7 are general-purpose rods, with helium 11 serving as a binding gas to contain the fission gases released after irradiation of the fuel or poison, preventing excessive pressure within the cladding 12. The stainless steel cladding 12 is the first safety barrier, isolating radioactive materials from the coolant. The material within the spectral-shifted combustible poison rod 7 is crucial for achieving the thermal neutron trap and reactivity control functions.
[0031] It is important to note that Figures 1-7 The colors are used to distinguish different structures.
[0032] The active zone, consisting of all fuel assemblies and lead-bismuth 4, has an equivalent diameter of 68 cm, an active zone height of 100 cm, a core power density of 27 W / cm³, an initial uranium loading of 1.05 t at the end of its life, and an average burnup depth of 48 GWd / tU at the end of its life. This constitutes a compact, long-life, high-burnup advanced lead-bismuth 4 fast reactor core, demonstrating that the present invention, through the combination of a thermal neutron trap and a spectral shift combustible poison, can successfully achieve efficient combustible poison reactivity control in a fast-spectrum reactor core.
[0033] In addition, the reactor core is equipped with a total of 19 fuel assemblies, including 4 low-enrichment fuel assemblies with safety rods 1, 3 low-enrichment fuel assemblies with regulating and compensating rods 2, and 12 high-enrichment fuel assemblies with regulating and compensating rods 3. The fuel assemblies are hexagonal prisms. The four low-enrichment fuel assemblies with safety rods 1 include one low-enrichment fuel assembly with safety rods located in the center. The remaining three abut against the three sides of the central low-enrichment fuel assembly with safety rods. The three low-enrichment fuel assemblies with regulating and compensating rods abut against the other three sides of the central low-enrichment fuel assembly with safety rods 1. The central low-enrichment fuel assemblies with safety rods 1 and the three low-enrichment fuel assemblies with regulating and compensating rods are staggered. The 12 high-enrichment fuel assemblies with regulating and compensating rods 3 are distributed between the low-enrichment fuel assemblies with safety rods 1 and the low-enrichment fuel assemblies with regulating and compensating rods 2. In addition, the safety rods 5, regulating rods and compensating rods can all be extracted or inserted by the corresponding drive mechanisms, which facilitates replacement and control.
[0034] In all fuel assemblies, the fuel rod 6 core 10 has a radius of 0.40 cm, the stainless steel cladding 12 has an inner diameter of 0.41 cm and an outer diameter of 0.47 cm, the center distance of the fuel rods 6 is 1.09 cm, and the grid pitch-to-diameter ratio is 1.16; each fuel assembly has 8 turns of fuel rod 6, with the control rod occupying 3 turns of fuel rod 6 space; in all fuel assemblies, the assembly box 8 has an inner side-to-side distance of 14.30 cm, an outer side-to-side distance of 14.70 cm, an assembly center distance of 14.90 cm, and the control rod guide tube has an outer side-to-side distance of 4.6 cm and an inner radius of 1.9 cm.
[0035] Example 2 As one embodiment, the spectral-shifting combustible poison material 17 is made of zirconium hydride. Matrix-dispersed erbium trioxide Among them, the low-enrichment fuel assembly containing safety rods 1 and the low-enrichment fuel assembly containing regulating compensation rods 2 The mass percentage is 1%, and the high enrichment of fuel assembly 3 containing regulating compensating rods is 3%. The mass percentage is 1.2%. Zirconium hydride matrix is a key moderator material for forming localized "thermal neutron traps." The hydrogen atoms in its lattice effectively slow down fast neutrons, creating a region within the poison rod where the proportion of thermal neutrons is significantly higher than the surrounding fast neutron environment. Erbium trioxide As a combustible poison, it possesses a relatively high absorption cross-section in the thermal neutron energy region. This can be achieved by adjusting the concentration of the poison in fuel assemblies with different enrichment levels. The proportion of reactivity control is precisely matched, which makes the high-power area in the periphery more reactive and ensures that the toxic substances in all areas are basically burned off by the end of their lifespan. Furthermore, in the low-enrichment safety rod fuel assembly 1 The B-10 content of core 10 is 90%, and the low enrichment of the regulating compensating rod fuel assembly 2 is... The B-10 content of core 10 is 30%, and the high enrichment of the regulating compensating rod fuel assembly 3 is... The B-10 content of core 10 is 40%.
[0036] This is a refined design tailored to the different functional requirements of the control rods. Safety rod 5 uses 90% high enrichment of B-10 to maximize its neutron absorption capacity per unit volume, ensuring the rapid introduction of a large negative reactivity in an emergency, with a total value of 6590 pcm, serving as the last barrier for core safety. The conditioning rods and compensation rods use 30% and 40% B-10 enrichment, respectively, which can significantly reduce their value per rod. The total value of the three conditioning rods is 1951 pcm, and the total value of the twelve compensation rods is 10776 pcm, ensuring that the average value per rod meets the rod jamming criterion requirements. Even if the most valuable bundle of rods is inserted uncontrollably, it will not trigger an instantaneous critical accident, greatly improving operational safety.
[0037] When the safety rod 5 and the adjustment and compensation rod 9 are extracted by the drive mechanism, the core rod extraction procedure will control the drive mechanism to perform the following extraction methods: fully lift the safety rod 5, raise the adjustment rod to half the core height, and raise the compensation rod to the core criticality. During the burnup process, the compensation rod is raised to compensate for the burnup reactivity loss, and the adjustment rod does not need to compensate for the reactivity requirements of the rise and fall power and the short-term reaction disturbance compensation. This is a tiered, coordinated control strategy. Safety rod 5, fully raised, ensures it can rapidly descend under gravity upon receiving a signal at any time; it is a dedicated safety feature and does not participate in regulation during normal operation. Regulation rod half-height standby enables it to adjust bidirectionally upwards or downwards to quickly respond to power changes. Compensation rods, used for criticality and burnup compensation, directly correspond to the core's transition from startup to operation, and the gradual release of residual reactivity as burnup increases.
[0038] This program clearly defines the roles of different control rods, achieving a balance between safety and operational flexibility. It automates and makes reactivity control of the reactor core throughout its lifespan predictable, minimizing operator intervention.
[0039] Example 3 As one embodiment, the combination of the metal hydride moderator material and the combustible poison material 17 in the spectral shift combustible poison rod 7 can be either a uniform mixture or a layered arrangement.
[0040] When using a uniform mixing method, for example, when The powder is uniformly dispersed in the zirconium hydride matrix. This arrangement allows the combustible poison particles to be completely immersed in the thermal neutron trap, maximizing their contact probability with thermal neutrons, thereby significantly increasing the burnup rate and most effectively reducing the amount of combustible poison residue at the end of the service life.
[0041] When using a layered arrangement, a metal hydride moderator such as zirconium hydride can be placed in the central region of the rod, and the surface of the rod can be coated with a layer of flammable poison material. This strategy can confine the effect of the thermal neutron trap more within the poison rod, reduce its interference with the energy spectrum of the surrounding fuel region, make the thermal neutron trap region more independent, and make the reactivity control effect of the spectrum-shifted combustible poison rod 7 more obvious and localized.
[0042] Furthermore, the selection of metal hydride moderators is not limited to zirconium hydride; other options include... or Uranium-containing hydrides; It is suitable for situations where there is a high demand for slowing down, as it contributes to the fission reaction while providing slowing down capabilities; It is suitable for situations where the moderation requirement is relatively small; the type and proportion of moderator can be adjusted according to the actual core physics design requirements to precisely control the intensity of the local thermal neutron trap.
[0043] remove In addition, the selection of flammable poison material 17 can also be... , Hf , Ag, In, Cd, etc.; The fastest burning rate, Secondly Hf , While relatively slow, by adjusting the type and proportion of poisons, reactivity control and burnup characteristics can be finely controlled to match the core design requirements of different lifespans and power densities.
[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A reactor core with spectral shift combustible poison rods using a thermal neutron trap design, characterized in that, Including low-enrichment fuel assemblies with safety rods (1), low-enrichment fuel assemblies with regulating compensating rods (2), high-enrichment fuel assemblies with regulating compensating rods (3), and lead-bismuth (4). The low-enrichment fuel assembly with safety rods (1) and the low-enrichment fuel assembly with adjustment and compensation rods (2) are located at the center of the reactor core. The low-enrichment fuel assembly with safety rods (1) and the low-enrichment fuel assembly with adjustment and compensation rods (2) are surrounded by a high-enrichment fuel assembly with adjustment and compensation rods (3). The high-enrichment fuel assembly with adjustment and compensation rods (3) is filled with lead-bismuth (4).
2. The reactor core with spectral shift combustible poison rods designed using a thermal neutron trap according to claim 1, characterized in that: The fuel enrichment of the low enrichment fuel assembly with safety rod (1) and the low enrichment fuel assembly with adjustment compensation rod (2) is 17%, and the fuel enrichment of the high enrichment fuel assembly with adjustment compensation rod (3) is 19.75%.
3. The reactor core with spectral shift combustible poison rods designed using a thermal neutron trap according to claim 1, characterized in that: The low enrichment fuel assembly with safety rod (1) is composed of a safety rod (5), a fuel rod (6), a spectral shift combustible poison rod (7), an assembly box (8), and lead-bismuth (4) from the inside out.
4. The reactor core with spectral shift combustible poison rods designed using a thermal neutron trap according to claim 3, characterized in that: The safety bar (5) has a structure that is formed from the inside out. It consists of a core (10), helium (11), stainless steel cladding (12), air (13), control rod guide rod (14) and lead bismuth (4).
5. The reactor core with spectral shift combustible poison rods designed using a thermal neutron trap according to claim 1, characterized in that: The low-enrichment fuel assembly with adjustment and compensation rod (2) and the high-enrichment fuel assembly with adjustment and compensation rod (3) are both composed of, from the inside out, a compensation rod, a fuel rod (6), a spectrum-shifting combustible poison rod (7), an assembly box (8), and lead-bismuth (4).
6. The reactor core with spectral shift combustible poison rods designed using a thermal neutron trap according to claim 5, characterized in that: The structure of the adjusting compensation rod (9) consists of, from the inside out, counterweight tungsten (15), helium (11), stainless steel cladding (12), and helium (11). It consists of a core (10), helium (11), stainless steel cladding (12), lead-bismuth (4), control rod guide tube and lead-bismuth (4).
7. The reactor core with spectral shift combustible poison rods designed using a thermal neutron trap, as described in any one of claims 3-5, is characterized in that: The structure of the fuel rod (6) consists of a fuel core (16), helium (11), stainless steel cladding (12), and lead-bismuth (4) from the inside out. The structure of the spectral shift combustible poison rod (7) consists of spectral shift combustible poison material (17), helium gas (11), stainless steel shell (12), and lead-bismuth (4) from the inside out.
8. The reactor core with spectral shift combustible poison rods designed using a thermal neutron trap according to any one of claims 3-5, characterized in that: The low-enrichment fuel assembly containing safety rods (1) The B-10 content of the core (10) is 90%, and the low enrichment of the regulating compensating rod fuel assembly (2) contains... The B-10 content of the core (10) is 30%, and the high enrichment of the regulating compensating rod fuel assembly (3) contains... The B-10 content of the core (10) is 40%.
9. The reactor core with spectral shift combustible poison rods designed using a thermal neutron trap according to claim 7, characterized in that: The spectral shift flammable poison material (17) is dispersed in a zirconium hydride matrix. The mass percentage of the spectral shift flammable poison material (17) in the low enrichment fuel assembly with safety rod (1) and the low enrichment fuel assembly with adjustment compensation rod (2) is 1%, and the mass percentage of the spectral shift flammable poison material (17) in the high enrichment fuel assembly with adjustment compensation rod (3) is 1.2%.
10. The reactor core with spectral shift combustible poison rods designed using a thermal neutron trap according to claim 7, characterized in that: The fuel type inside the fuel core (16) is or .