Hybrid Energy Spectrum Supercritical Water Reactor

Abstract

This invention relates to the field of reactor technology, specifically to a hybrid energy spectrum supercritical water reactor. The hybrid energy spectrum supercritical water reactor includes a shell, thermal fuel assemblies, and fast fuel assemblies. The thermal region is vertically arranged with alternating thermal fission and regeneration zones; the fast region is vertically arranged with alternating fast fission and regeneration zones. The thermal fuel assemblies are housed in the thermal region, and the fast fuel assemblies are housed in the fast region, all with the same fuel arrangement. In this hybrid energy spectrum supercritical water reactor, no separate moderator channel is required to obtain the required neutron energy spectrum, simplifying the core structure while ensuring safe and efficient reactor operation.

Description

Technical Field

[0001] This invention relates to the field of reactor technology, and more specifically, to a hybrid energy spectrum supercritical water reactor. Background Technology

[0002] Supercritical water reactors are one of the fourth-generation nuclear reactor designs. These reactors use supercritical water at high temperatures and pressures (over 374°C and 22.1 MPa) as both coolant and moderator. Utilizing its high specific heat and lack of phase change in the quasi-critical region, supercritical water reactors offer advantages such as high thermal efficiency and system simplicity. Nuclear reactors can be classified according to their neutron energy spectrum into thermal reactors, fast reactors, and hybrid energy spectrum reactors. Thermal neutron reactors utilize thermal neutrons to initiate nuclear fission, thus requiring moderators (such as water, graphite, or ZrH) to reduce neutron velocity and increase the likelihood of fission reactions occurring in the reactor. Core components typically include fuel rods, moderator rods, and guide tubes, resulting in a relatively complex structure. Fast neutron reactors, on the other hand, typically use high-energy fast neutrons to maintain chain reactions in the reactor without the need for moderators. However, they suffer from excessively high local heat pipes and hot spot factors, high cladding temperatures, and non-uniform circumferential heat transfer. They also have smaller core water capacity, lower fuel utilization, and generate large amounts of long-lived radioactive waste, posing a threat to the environment and requiring higher overall safety standards.

[0003] Hybrid-spectrum reactors possess both fast and hot spectral regions, combining the advantages of both to improve overall reactor performance. However, existing hybrid-spectrum supercritical water reactors are sodium-cooled MXRs, with a harder neutron spectrum than supercritical water reactors. They also require more moderator materials to achieve negative cavitation reactivity, which reduces the breed ratio and increases burnup reactivity loss. The combination of multiple different components increases the complexity of the core assembly, leading to significantly higher research and operating costs. Summary of the Invention

[0004] The purpose of this invention is to provide a hybrid energy spectrum supercritical water reactor to solve the technical problem of complex structure in existing hybrid energy spectrum reactors.

[0005] This invention provides a hybrid energy spectrum supercritical water reactor, comprising:

[0006] The housing has an inlet, an outlet, a thermal spectrum region, and a fast spectrum region. The thermal spectrum region and the fast spectrum region are arranged sequentially from the outside to the inside of the housing along the radial direction and are isolated from each other. The thermal spectrum region has alternating thermal fission regions and thermal regeneration regions arranged vertically, and the inlet is connected to the upper end of the thermal spectrum region. The fast spectrum region has alternating fast fission regions and fast regeneration regions arranged vertically, and the outlet is connected to the upper end of the fast spectrum region. The lower end of the thermal spectrum region is connected to the lower end of the fast spectrum region to send the coolant flowing out of the thermal spectrum region into the fast spectrum region.

[0007] A thermal spectrum fuel assembly, housed in the thermal spectrum region;

[0008] A fast-spectrum fuel assembly is housed in the fast-spectrum region;

[0009] The thermal fuel assembly in the thermal spectrum region has the same fuel configuration as the fast fuel assembly in the fast spectrum region.

[0010] Optionally, the thermal spectrum fuel assembly includes a thermal spectrum assembly box and a plurality of thermal spectrum fuel rods arranged in a rectangular array at intervals within the thermal spectrum assembly box; the fuel in the thermal spectrum fuel rods located in the thermal spectrum regeneration zone is spent fuel, and the fuel in the thermal spectrum fuel rods located in the thermal spectrum fission zone is N2. R % of plutonium uranium oxide; of which, N R The value ranges from 23 to 25.

[0011] Optionally, the thermal spectrum fuel assembly is M. R ×M R Square grid element, where M R M is the number of thermal spectral fuel rods arranged laterally or longitudinally in a single thermal spectral fuel assembly. R The value ranges from 17 to 19.

[0012] Optionally, the height of the thermal spectrum fission region is 39cm to 41cm, and the height of the thermal spectrum regeneration region between adjacent thermal spectrum fission regions is 39cm to 41cm; vertically, the top and bottom layers of the thermal spectrum region are both thermal spectrum regeneration regions, wherein the height of the top thermal spectrum regeneration region and the bottom thermal spectrum regeneration region are both 44cm to 46cm.

[0013] Optionally, the fast-spectrum fuel assembly includes a fast-spectrum assembly box and a plurality of fast-spectrum fuel rods arranged in a rectangular array at intervals within the fast-spectrum assembly box; the fuel in the fast-spectrum fuel rods located in the fast-spectrum regeneration zone is spent fuel, and the fuel in the fast-spectrum fuel rods located in the fast-spectrum fission zone is N2. K % of plutonium uranium oxide; of which, N K The value ranges from 23 to 25.

[0014] Optionally, the fast-spectrum fuel assembly is M. K ×M K Square grid element, where M K M is the number of fast-spectrum fuel rods arranged laterally or longitudinally in a single fast-spectrum fuel assembly. K The value ranges from 17 to 19.

[0015] Optionally, the height of the fast spectrum fission region is 39cm to 41cm, and the height of the fast spectrum regeneration region between adjacent fast spectrum fission regions is 39cm to 41cm; vertically, the top and bottom layers of the fast spectrum region are both fast spectrum regeneration regions, wherein the height of the top layer fast spectrum regeneration region and the bottom layer fast spectrum regeneration region are both 44cm to 46cm.

[0016] Optionally, within the housing, an upper partition, a spacer, and a lower partition are sequentially spaced from top to bottom; an upper sleeve and an upper partition are radially fitted from the outside to the inside; a lower sleeve and a lower partition are radially fitted from the outside to the inside; the lower partition is connected to the upper partition; the lower sleeve, the lower partition, the spacer, and the lower partition form the thermal spectrum region; the lower partition, the spacer, and the lower partition form the fast spectrum region.

[0017] The hybrid energy spectrum supercritical water reactor provided by this invention has the following beneficial effects:

[0018] The hybrid supercritical reactor core is radially divided into an outer thermal spectrum region and an inner fast spectrum region. Supercritical water, as the coolant, flows into the shell from the inlet, first flowing downwards along the outer thermal spectrum region, then upwards to the fast spectrum region to cool it. Finally, the coolant flows out from the top of the fast spectrum region and then out from the shell outlet. The thermal fuel assemblies in the thermal spectrum region have the same fuel arrangement as the fast fuel assemblies in the fast spectrum region. During the downward flow of the coolant in the thermal spectrum region, before the water temperature reaches the pseudocritical temperature, the water has a higher density and a relatively high uranium mass. The neutron energy spectrum is large, and the neutron moderation capability is strong. At this time, there is no need to add an additional moderator channel to increase the water-uranium mass ratio. During the upward flow of the coolant in the fast spectrum region, when the coolant water has reached the supercritical state, the density of water drops sharply, the water-uranium mass ratio decreases, and a harder neutron energy spectrum is obtained. Therefore, in this embodiment, the thermal fuel assembly in the thermal spectrum region and the fast fuel assembly in the fast spectrum region are set with the same fuel setting method. There is no need to set an additional moderator channel. The required neutron energy spectrum can be obtained. Under the premise of ensuring safe and efficient operation of the reactor, the core structure is simplified. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the cross-sectional structure of a hybrid energy spectrum supercritical water reactor provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of one cross-sectional structure in an embodiment of the present invention;

[0022] Figure 3 This is a schematic cross-sectional view of a thermal spectrum fuel assembly (fast spectrum fuel assembly) in an embodiment of the present invention;

[0023] Figure 4 In an embodiment of the present invention, Figure 3 Schematic diagram of the middle quarter section;

[0024] Figure 5 This is a schematic diagram of one longitudinal section of a thermal spectrum fuel assembly (fast spectrum fuel assembly) in an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of the axial power distribution of the fuel rods in a thermal spectrum fuel assembly (fast spectrum fuel assembly) according to an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the temperature distribution at the center of the fuel rod cladding and pellet in an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 100 - Housing;

[0029] 101 - Upper partition; 102 - Partition plate; 103 - Lower partition;

[0030] 104 - Upper sleeve; 105 - Upper partition; 106 - Lower sleeve; 107 - Lower partition;

[0031] 108 - Upper head; 109 - Lower head;

[0032] 110 - Entrance; 120 - Exit;

[0033] 130 - Thermal spectrum region; 131 - Thermal spectrum fission region; 132 - Thermal spectrum regeneration region;

[0034] 140 - Fast spectrum region; 141 - Fast spectrum fission region; 142 - Fast spectrum regeneration region;

[0035] 150 - First buffer chamber; 160 - Second buffer chamber; 170 - Transition buffer chamber; 180 - Connecting cylinder;

[0036] 200-Thermal Spectrum Fuel Assembly;

[0037] 210 - Thermal spectrum component box; 220 - Thermal spectrum fuel rod; 230 - Thermal spectrum coolant subchannel;

[0038] 300-Fast Spectrum Fuel Assembly;

[0039] 310 - Fast spectrum component box; 320 - Fast spectrum fuel rod; 330 - Fast spectrum coolant subchannel. Detailed Implementation

[0040] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0042] This invention provides a hybrid energy spectrum supercritical water reactor, such as... Figures 1-2 As shown, the hybrid energy spectrum supercritical water reactor includes: a shell 100, a thermal energy spectrum fuel assembly 200, and a fast energy spectrum fuel assembly 300.

[0043] In this embodiment, as Figure 1 As shown, the housing 100 has an inlet 110, an outlet 120, a thermal spectrum region 130, and a fast spectrum region 140. The thermal spectrum region 130 and the fast spectrum region 140 are arranged sequentially from the outside to the inside of the housing 100 along the radial direction and are isolated from each other. Figure 5 As shown, the thermal spectrum region 130 is vertically arranged with alternating thermal spectrum fission region 131 and thermal spectrum regeneration region 132, and the inlet 110 is connected to the upper end of the thermal spectrum region 130; as Figure 5 As shown, the fast spectrum region 140 is vertically arranged with alternating fast spectrum fission region 141 and fast spectrum regeneration region 142, and the outlet 120 is connected to the upper end of the fast spectrum region 140; as Figure 1 As shown, the lower end of the thermal spectrum region 130 is connected to the lower end of the fast spectrum region 140 to send the coolant flowing out of the thermal spectrum region 130 into the fast spectrum region 140; the thermal spectrum fuel assembly 200 of the thermal spectrum region 130 and the fast spectrum fuel assembly 300 of the fast spectrum region 140 have the same fuel setting method.

[0044] In this embodiment, as Figure 1 As shown, the thermal spectrum fuel assembly 200 is housed in the thermal spectrum region 130, as... Figures 3-4 As shown, the thermal spectrum fuel assembly 200 includes a thermal spectrum assembly box 210 and a plurality of thermal spectrum fuel rods 220 arranged in a rectangular array at intervals within the thermal spectrum assembly box 210; the fuel in the thermal spectrum fuel rods 220 located in the thermal spectrum regeneration region 132 is spent fuel, and the fuel in the thermal spectrum fuel rods 220 located in the thermal spectrum fission region 131 is N. R % of plutonium uranium oxide; of which, N R The value ranges from 23 to 25;

[0045] In this embodiment, as Figure 1 As shown, the fast-spectrum fuel assembly 300 is housed in the fast-spectrum region 140, as... Figures 3-4 As shown, the fast spectrum fuel assembly 300 includes a fast spectrum assembly box 310 and a plurality of fast spectrum fuel rods 320 arranged in a rectangular array at intervals within the fast spectrum assembly box 310; the fuel in the fast spectrum fuel rods 320 located in the fast spectrum regeneration zone 142 is spent fuel, and the fuel in the fast spectrum fuel rods 320 located in the fast spectrum fission zone 141 is N. K % of plutonium uranium oxide; of which, N K The value ranges from 23 to 25.

[0046] In this embodiment of the invention, the mixed-energy supercritical reactor core is divided radially from the outside to the inside into an outer thermal spectrum region and an inner fast spectrum region. Supercritical water, as the coolant, flows into the shell from the inlet, first flowing downwards along the outer thermal spectrum region, then upwards to the fast spectrum region to cool it. Finally, the coolant flows out from the upper end of the fast spectrum region and then out from the shell outlet. The thermal fuel assembly in the thermal spectrum region has the same fuel arrangement as the fast fuel assembly in the fast spectrum region. During the downward flow of the coolant in the thermal spectrum region, before the water temperature reaches the pseudocritical temperature, due to the high density of water... The water-uranium mass ratio is relatively large, resulting in a strong neutron moderation capability. Therefore, there is no need to add an additional moderator channel to increase the water-uranium mass ratio. As the coolant flows upward in the fast spectrum region, the water coolant reaches a supercritical state, causing a sharp decrease in water density and a reduction in the water-uranium mass ratio, thus resulting in a harder neutron spectrum. Therefore, in this embodiment, the thermal fuel assembly in the thermal spectrum region has the same fuel arrangement as the fast fuel assembly in the fast spectrum region. There is no need to set up a separate moderator channel, and the required neutron spectrum can still be obtained. This simplifies the core structure while ensuring the safe and efficient operation of the reactor.

[0047] In this embodiment, as Figures 3-4 As shown, the thermal spectrum fuel assembly 200 is M R ×M R Square grid element, where M R M is the number of thermal fuel rods 220 arranged laterally or longitudinally in a single thermal fuel assembly 200. R The value ranges from 17 to 19, with 18 being the preferred value; for example... Figures 3-4 As shown, the fast-spectrum fuel assembly 300 is M K ×M K Square grid element, where M K M is the number of fast-spectrum fuel rods 320 arranged laterally or longitudinally in a single fast-spectrum fuel assembly 300. K The value ranges from 17 to 19, with 18 being the preferred value.

[0048] In this embodiment, as Figure 5 As shown, the height D1 of the thermal fission region 131 is 39cm to 41cm, preferably 40cm; the height D2 of the thermal regeneration region 132 between adjacent thermal fission regions 131 is 39cm to 41cm, preferably 40cm; vertically, the top and bottom layers of the thermal region 130 are both thermal regeneration regions 132, wherein the height D3 of both the top and bottom thermal regeneration regions 132 is 44cm to 46cm, preferably 45cm. Figure 5 As shown, the height value d1 of the fast spectrum fission region 141 is 39cm to 41cm, and the height value d2 of the fast spectrum regeneration region 142 between adjacent fast spectrum fission regions 141 is 39cm to 41cm; vertically, the top and bottom layers of the fast spectrum region 140 are both fast spectrum regeneration regions 142, and the height value d3 of the top layer fast spectrum regeneration region 142 and the bottom layer fast spectrum regeneration region 142 are both 44cm to 46cm.

[0049] In this embodiment, the thermal spectrum fuel assembly 200 in the thermal spectrum region 130 has the same structure and parameters as the fast spectrum fuel assembly 300 in the fast spectrum region 140. (M) R and M K Taking 18 as an example.

[0050] In this embodiment, as Figure 1 As shown, inside the housing 100, an upper partition 101, a partition 102, and a lower partition 103 are arranged sequentially from top to bottom. An upper sleeve 104 and an upper partition 105 are arranged radially from the outside to the inside. A lower sleeve 106 and a lower partition 107 are arranged radially from the outside to the inside. The lower partition 107 is connected to the upper partition 105. The lower sleeve 106, the lower partition 107, the partition 102, and the lower partition 103 form a thermal spectrum region 130, and the lower partition 107, the partition 102, and the lower partition 103 form a fast spectrum region 140.

[0051] In this embodiment, as Figure 1 As shown, the housing 100 has an upper end cap 108; the upper end cap 108 and the upper partition 101 form a first buffer cavity 150, which is connected to the upper end of the inlet 110 and the thermal spectrum region 130.

[0052] In this embodiment, as Figure 1 As shown, the upper partition 101, the partition 102, the upper sleeve 104 and the upper partition cylinder 105 form a second buffer cavity 160, which is connected to the upper end of the outlet 120 and the fast spectrum region 140.

[0053] In this embodiment, as Figure 1 As shown, the side wall of the upper partition cylinder 105 has multiple upper through holes, and the upper partition cylinder 105 is connected to the second buffer chamber 160 through the upper through holes.

[0054] In this embodiment, as Figure 1 As shown, the housing 100 has a lower end cap 109, and the lower end cap 109, the lower partition 103 and the lower sleeve 106 form a transition buffer cavity 170. The lower partition 103 is provided with a first lower through hole and a second lower through hole. The thermal spectrum region 130 is connected to the transition buffer cavity 170 through the first lower through hole, and the fast spectrum region 140 is connected to the transition buffer cavity 170 through the second lower through hole.

[0055] In this embodiment, as Figure 1 As shown, it also includes a connecting cylinder 180, which is located in the second buffer chamber 160. The upper end of the connecting cylinder 180 is sealed and fixed to the upper partition 101 and connected to the first buffer chamber 150, and the lower end is sealed and fixed to the partition 102 and connected to the thermal spectrum region 130.

[0056] In this embodiment of the invention, the core working principle is as follows: supercritical water, as the coolant, first flows downward along the thermal spectrum region outside the core to the transition buffer chamber 170 (lower chamber), then flows upward to the fast spectrum region for cooling, and finally the coolant flows out from the outlet 120 of the pressure vessel shell 100. Specifically, in the descending phase, before the water temperature reaches the quasi-critical temperature, the water density is high, resulting in a large water-uranium mass ratio and strong neutron moderation capability. Therefore, it is not necessary to add a moderator channel to further increase the water-uranium mass ratio. In the ascending phase, the coolant water reaches a state above supercriticality, the water density decreases sharply, and the water-uranium mass ratio decreases significantly, thereby optimizing neutron economy and improving the fuel conversion ratio, resulting in a harder neutron spectrum, thus improving the fuel conversion ratio and fuel utilization. In this embodiment of the invention, the same component structure parameters are used in different energy spectrum regions of the reactor core. Due to the corresponding physical properties of water in the supercritical state, the density of water drops sharply after the temperature exceeds the quasi-critical temperature. Using a low-density coolant can ensure that fuel assemblies with a large grid diameter ratio can be used while maintaining a low water-uranium ratio. This geometric feature can effectively improve the problem of uneven heat transfer in the circumferential direction of the cladding and improve the overall safety margin of the reactor core. Since the same component parameters are used in different energy spectrum regions of the reactor core, the moderator channel and multi-layer enrichment arrangement in the thermal spectrum region are eliminated. The design of the supercritical mixed energy spectrum water reactor is achieved only by changing the water-uranium mass ratio. This simplifies the core structure and reduces the cost of research and development and operation and maintenance while meeting the requirements of safe and efficient reactor operation.

[0057] The following is a specific example to further illustrate the invention.

[0058] In this embodiment, a total of 284 fuel assemblies are arranged along the cross-section of the reactor core. Among them, 120 are fast-spectrum fuel assemblies in the fast-spectrum region and 164 are thermal-spectrum fuel assemblies in the thermal-spectrum region. The schematic diagram of the core assembly arrangement is shown below. Figure 2As shown, the fuel rods in the fuel assemblies of the thermal and fast spectrum regions are arranged in the same way, both using 18x18 square grid cells. The thermal fuel rods 220 are evenly arranged in the thermal assembly box 210 with an outer edge distance of 166.5 mm and a wall thickness of 2 mm. The outer diameter of the thermal fuel rods 220 is 7.5 mm and the grid pitch is 9.0 mm. The fast fuel rods 320 are evenly arranged in the fast assembly box 310 with an outer edge distance of 166.5 mm and a wall thickness of 2 mm. The outer diameter of the fast fuel rods 320 is 7.5 mm and the grid pitch is 9.0 mm. Along the core axis, the thermal spectrum region 130 consists of alternating thermal fission region 131 and thermal regeneration region 132, and the fast spectrum region 140 consists of alternating fast fission region 141 and fast regeneration region 142. In the thermal fission region 131 and fast fission region 141, fission reactions mainly occur and generate a large amount of energy. In the thermal regeneration region 132 and fast regeneration region 142, the leakage of neutrons in the corresponding fission regions is mainly enhanced, ensuring negative coolant cavitation reactivity and realizing the conversion of easily fissile fuel. Plutonium-uranium oxide (MOX) with an enrichment of approximately 24% is used as the material for the thermal fuel rod 220 in the thermal fission region 131, and plutonium-uranium oxide (MOX) with an enrichment of approximately 24% is used as the material for the fast fuel rod 320 in the fast fission region 141. High-burnup spent fuel (DU) is used as the material for the thermal fuel rod 220 in the thermal regeneration region 132, and high-burnup spent fuel (DU) is used as the material for the fast fuel rod 320 in the fast regeneration region 142. The fuel rod materials in the thermal fission region 131 and the thermal regeneration region 132 are arranged alternately, for a total of 11 layers. Similarly, the fuel rod materials in the fast fission region 141 and the fast regeneration region 142 are arranged alternately, also for a total of 11 layers. The top and bottom of the thermal region 130 are both thermal regeneration regions 132, with a height of 45 cm; the remaining sections are all 40 cm high. Likewise, the top and bottom of the fast region 140 are both fast regeneration regions 142, with a height of 45 cm; the remaining sections are all 40 cm high. Figure 5 As shown, detailed geometric parameters are shown in Table 1.

[0059] Table 1. Fuel rod structure and fuel geometry parameters:

[0060]

[0061] Table 2 below shows the parameters of the reference core of the hybrid energy spectrum supercritical water-cooled reactor. The coolant inlet temperature is 280°C, and the outlet temperature is 510°C. It is assumed that the coolant water is heated to approximately 390°C on average through the thermal spectrum region. The overall core power is approximately 3800 MW, with an average linear power density of 22.5 kW / m² in the thermal spectrum region and 18.0 kW / m² in the fast spectrum region. The overall core height is 4.5 meters, with an effective height of 2 meters (the total height of the fission zone).

[0062] Table 2 Core Operation Design Parameters:

[0063]

[0064] The axial power distribution of the fuel assembly was calculated using the MCNP program. Axial power distribution is defined as the ratio of the heat flux density in a certain axial region to the average heat flux density in the fission zone. For example... Figure 5 As shown, the fuel assemblies in the thermal and fast spectrum regions are axially divided into 11 layers according to the fission and regeneration regions, as follows. Figure 6 As shown, a schematic diagram of the axial power distribution of an 11-layer fuel assembly is presented. The fission zone mainly undergoes fission reactions, and its power is much greater than that of the regeneration zone. Therefore, the axial power distribution in the fission zone will show a peak value. The fuel assembly has a total of 5 fission zones, so the axial power distribution contains five power peak segments. When the coolant water flows along the axial direction, it continuously cools the fuel rods. The temperature rises, causing the coolant density to gradually decrease, the fast neutron flux to increase, and the axial power to gradually increase accordingly. When the coolant density decreases to a certain value, the neutron flux decreases due to neutron leakage in the fission zone, which further leads to a decrease in axial power. Therefore, the axial power generally shows a trend of first increasing and then decreasing.

[0065] This embodiment also uses the COBRA-SC program to perform sub-channel calculation and analysis on the core assemblies. Specifically, due to the symmetrical distribution of the fuel assemblies, one-quarter of the assembly is used for modeling, such as... Figure 4 As shown, the fuel rods (220 / 230) and coolant sub-channels (230 / 330) within the quarter-assembly are divided and numbered. The fuel parameters, geometric parameters, operating parameters, and axial power distribution of the core fuel assembly are consistent with those in the table above. The heat transfer model between the fuel rod cladding and the coolant adopts the existing Watts formula, with a mixing coefficient of 0.10. Table 3 below is a summary table of the calculation results for the two types of fuel assembly sub-channels.

[0066] Table 3, Preliminary calculation results for sub-channels:

[0067]

[0068] The calculation results show that the peak temperatures of the fuel rod cladding and the center of the pellet both occur at the No. 1 rod, i.e., the corner of the assembly. This is because the equivalent diameter of the sub-channel at the corner is smaller, and the coolant mass flow rate is smaller, resulting in a less effective cooling effect on the fuel rod at the corner compared to other locations.

[0069] In Table 3, the outlet temperature of the thermal spectrum region, which is also the inlet temperature of the fast spectrum region, is 393.50℃. The fuel rods in both the thermal and fast spectrum regions reach their highest cladding temperatures at rod number 1, at 513.37℃ and 511.39℃ respectively. For austenitic stainless steel cladding, the internationally accepted temperature design limit for cladding materials during steady-state operation is currently 650℃. Excessive temperatures reduce the corrosion resistance and mechanical properties of the cladding material, posing a threat to reactor safety. Therefore, the fuel rod cladding temperature should be as low as possible. In this embodiment, the peak fuel rod temperature is far below the design limit, meeting the design requirements. Compared with the calculation results of existing SCWR-M components, the highest fuel rod cladding temperature in the thermal spectrum region in this embodiment is 513.37℃, slightly higher than the SCWR-M thermal spectrum region cladding peak temperature of 499.0℃, but still within the design requirements. The peak fuel rod cladding temperature in the fast spectrum region is 598.55℃, lower than the SCWR-M fast spectrum region cladding peak temperature of 617.2℃.

[0070] Table 3 shows that excessively high fuel rod pellet temperatures can lead to pellet melting, radioactive material leakage, and uncontrolled, violent reactions. Therefore, the maximum temperature of the fuel rod pellets should be lower than their melting point at corresponding burnup, the maximum linear power density should be less than 39 kW / m³, and the fuel pellet center temperature should be maintained below 2000℃. While meeting these requirements, the pellet center temperature should also be kept as low as possible. Calculation results show that the maximum power densities in the thermal and fast spectral regions of this patent are 28.72 kW / m³ and 22.90 kW / m³, respectively, both below 39 kW / m³, meeting the requirements; the maximum fuel pellet center temperatures are 1468.61℃ and 1333.56℃, respectively, both far below 2000℃, also meeting the requirements. Compared with SCWR-M, the fuel pellet center temperatures of 1468.61℃ and 1333.56℃ in both the fast and hot spectrum regions are lower than those in SCWR-M (1670.0℃ and 1375.0℃). In other words, the core provided in this embodiment is superior to the core provided by SCWR-M.

[0071] In summary, compared with the calculation results of the SCWR-M component, although the highest fuel rod cladding temperature of 513.37℃ in the thermal spectrum region of the fuel rod assembly provided in this embodiment of the invention is slightly higher than the peak cladding temperature of 499.0℃ in the thermal spectrum region of the SCWR-M component, the fuel rod cladding temperature in the fast spectrum region and the center temperature of the fuel pellet are both lower than the corresponding data of the SCWR-M component. Its overall performance is significantly better than that of the SCWR-M component.

[0072] In this embodiment, the axial temperature distribution at the center of the fuel cladding and pellet is as follows: Figure 7As shown, the radial zoning arrangement results in segmented temperature variations in the fuel cladding and pellet center. In the fission zone, the axial power factor is large, leading to higher temperatures in both the cladding and pellets, exhibiting a peak value. In the regeneration zone, the axial power factor is smaller, resulting in lower and more stable temperatures. Figure 7 As shown, the axial design adopts a partitioned design of fission zone and regeneration zone, which flattens the temperature of the cladding and core to a certain extent, thus making the temperature distribution more uniform; the core center temperature in the thermal spectrum region is reduced by nearly 200℃ compared with the existing technology "SCWR-M".

[0073] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0074] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "installation" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hybrid energy spectrum supercritical water reactor, characterized in that, include: The housing (100) has an inlet (110), an outlet (120), a thermal spectrum region (130), and a fast spectrum region (140). The thermal spectrum region (130) and the fast spectrum region (140) are arranged radially from the outside to the inside within the housing (100) and are isolated from each other. The thermal spectrum region (130) is vertically arranged with alternating thermal spectrum fission region (131) and thermal spectrum regeneration region (132). The inlet (110) is connected to... The outlet (120) is connected to the upper end of the thermal spectrum region (130); the fast spectrum region (140) is vertically arranged with a fast spectrum fission region (141) and a fast spectrum regeneration region (142) alternately, and the outlet (120) is connected to the upper end of the fast spectrum region (140); the lower end of the thermal spectrum region (130) is connected to the lower end of the fast spectrum region (140) so as to send the coolant flowing out of the thermal spectrum region (130) into the fast spectrum region (140). A thermal spectrum fuel assembly (200) is housed in the thermal spectrum region (130); Fast spectrum fuel assembly (300) is housed in the fast spectrum region (140). The thermal spectrum fuel assembly (200) in the thermal spectrum region (130) and the fast spectrum fuel assembly (300) in the fast spectrum region (140) have the same fuel setting method. The thermal spectrum fuel assembly (200) includes a thermal spectrum assembly box (210) and a plurality of thermal spectrum fuel rods (220) arranged in a rectangular array at intervals within the thermal spectrum assembly box (210); the fuel in the thermal spectrum fuel rods (220) located in the thermal spectrum regeneration region (132) is spent fuel, and the fuel in the thermal spectrum fuel rods (220) located in the thermal spectrum fission region (131) is N. R % of plutonium uranium oxide; of which, N R The value of is 24; The fast-spectrum fuel assembly (300) includes a fast-spectrum assembly box (310) and a plurality of fast-spectrum fuel rods (320) arranged in a rectangular array at intervals within the fast-spectrum assembly box (310); the fuel in the fast-spectrum fuel rods (320) located in the fast-spectrum regeneration zone (142) is spent fuel, and the fuel in the fast-spectrum fuel rods (320) located in the fast-spectrum fission zone (141) is N2. K % of plutonium uranium oxide; of which, N K The value is 24.

2. The hybrid energy spectrum supercritical water reactor according to claim 1, characterized in that, The thermal fuel assembly (200) is M R ×M R Square grid element, where M R M is the number of thermal fuel rods (220) arranged laterally or longitudinally in a single thermal fuel assembly (200), wherein M R The value ranges from 17 to 19.

3. The hybrid energy spectrum supercritical water reactor according to claim 2, characterized in that, The height of the thermospectral fission region (131) is 39cm to 41cm, and the height of the thermospectral regeneration region (132) between adjacent thermospectral fission regions (131) is 39cm to 41cm; along the vertical direction, the top and bottom layers of the thermospectral region (130) are both thermospectral regeneration regions (132), wherein the height of the top thermospectral regeneration region (132) and the bottom thermospectral regeneration region (132) are both 44cm to 46cm.

4. The hybrid energy spectrum supercritical water reactor according to claim 1, characterized in that, The fast-spectrum fuel assembly (300) is M K ×M K Square grid element, where M K M is the number of fast-spectrum fuel rods (320) arranged laterally or longitudinally in a single fast-spectrum fuel assembly (300), wherein M K The value ranges from 17 to 19.

5. The hybrid energy spectrum supercritical water reactor according to claim 4, characterized in that, The height of the fast spectrum fission region (141) is 39cm to 41cm, and the height of the fast spectrum regeneration region (142) between adjacent fast spectrum fission regions (141) is 39cm to 41cm; along the vertical direction, the top and bottom layers of the fast spectrum region (140) are both fast spectrum regeneration regions (142), wherein the height of the top layer fast spectrum regeneration region (142) and the bottom layer fast spectrum regeneration region (142) are both 44cm to 46cm.

6. The hybrid energy spectrum supercritical water reactor according to any one of claims 1-5, characterized in that, Inside the housing (100), an upper partition plate (101), a partition plate (102), and a lower partition plate (103) are arranged sequentially from top to bottom. An upper sleeve (104) and an upper partition cylinder (105) are arranged radially from the outside to the inside. A lower sleeve (106) and a lower partition cylinder (107) are arranged radially from the outside to the inside. The lower partition cylinder (107) is connected to the upper partition cylinder (105). The lower sleeve (106), the lower partition cylinder (107), the partition plate (102), and the lower partition plate (103) form the thermal spectrum region (130). The lower partition cylinder (107), the partition plate (102), and the lower partition plate (103) form the fast spectrum region (140).

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