Reactor core structure and liquid metal cooling fast reactor

Abstract

The embodiment of the invention relates to the technical field of nuclear reactors, in particular to a reactor core structure and a liquid metal cooling fast reactor. The reactor core structure comprises a grid assembly, an auxiliary assembly, a stainless steel assembly, a fuel assembly, an adjusting assembly and an irradiation assembly, wherein a plurality of pore channels are formed in the grid assembly; the auxiliary assembly is arranged in the pore channel located on the outermost periphery; the stainless steel assembly is closer to the middle duct than the auxiliary assembly; the fuel assembly is closer to the middle duct than the stainless steel assembly; the adjusting assembly is arranged in a hole channel around the fuel assembly; the irradiation components are arranged in the pore channel near the middle part, the pore channel adjacent to the fuel component and the pore channel between the fuel component and the stainless steel component; fuel in the fuel assembly comprises oxide fuel, and the fuel assembly is set to be that the total neutron fluence rate of the reactor core structure is not lower than a preset value. According to the reactor core structure and the liquid metal cooling fast reactor provided by the embodiment of the invention, a relatively high neutron fluence rate can be provided, and the reactor belongs to a high-flux reactor.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of nuclear reactors, and in particular to a core structure and a liquid metal cooled fast reactor. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] For neutron injection rates close to or greater than 5×10 15 n / (cm 2 ·s) can be called a high-flux reactor. High-flux reactors play an important role in advanced fuel research, production of special isotopes, and exploration of basic nuclear technologies. However, my country currently lacks service application performance data of high-flux reactors, which has led to slow research progress in related areas. Summary of the invention

[0004] A brief overview of the present application is provided below in order to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0005] A first aspect of an embodiment of the present application provides a core structure of a reactor, which includes: a grid assembly, an auxiliary assembly, a stainless steel assembly, a fuel assembly, an adjustment assembly and an irradiation assembly, wherein a plurality of channels adjacent to each other are formed in the grid assembly; the auxiliary assembly is arranged in the outermost channels of the plurality of channels; the stainless steel assembly is closer to the middle of the plurality of channels than the auxiliary assembly; the fuel assembly is arranged in the channel closer to the middle of the plurality of channels than the stainless steel assembly; the adjustment assembly is used to adjust the reactivity of the reactor, and the adjustment assembly is arranged in the channels around the channels where the fuel assembly is arranged; the irradiation assembly is used to be irradiated to produce the required substance, and the irradiation assembly is arranged in the channels near the middle of the plurality of channels, and in the channels adjacent to the fuel assembly, and in the channels between the fuel assembly and the stainless steel assembly; wherein the fuel in the fuel assembly includes oxide fuel, and the fuel assembly is arranged so that the total neutron injection rate of the core structure is not less than a predetermined value.

[0006] A second aspect of an embodiment of the present application provides a liquid metal cooled fast reactor, which includes the core structure provided by the first aspect of an embodiment of the present application.

[0007] The core structure and liquid metal-cooled fast reactor provided in the embodiments of the present application can provide a higher neutron injection rate and belong to a high-flux reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to further illustrate the above and other advantages and features of the present application, the specific embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. The accompanying drawings together with the following detailed description are included in this specification and form a part of this specification. Elements with the same function and structure are represented by the same reference numerals. It should be understood that these drawings only describe typical examples of the present application and should not be regarded as limiting the scope of the present application.

[0009] Figure 1 is a structural schematic diagram of a core structure according to an embodiment of the present application;

[0010] Figure 2 is a BOC maximum neutron fluence rate distribution diagram of a reactor provided according to an embodiment of the present application;

[0011] Figure 3 is a distribution diagram of the maximum neutron fluence rate of the EOC of the reactor provided according to an embodiment of the present application;

[0012] Figure 4 It is a maximum radiation damage dose distribution diagram of each component within a cycle period provided according to an embodiment of the present application.

[0013] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner that does not affect the reader's understanding.

[0014] Explanation of the reference numerals: 10. Auxiliary assembly; 11. Shielding member; 12. Storage member; 20. Stainless steel assembly; 30. Fuel assembly; 31. First fuel assembly; 32. Second fuel assembly; 41. Compensating rod; 42. Safety rod; 43. Passive rod; 44. Adjusting rod; 50. Irradiation assembly; 60. Opening. DETAILED DESCRIPTION

[0015] Exemplary embodiments of the present application will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual implementation are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the process of developing any such actual implementation in order to achieve the developer's specific goals, such as meeting those constraints related to the system and business, and these constraints may vary from implementation to implementation. In addition, it should be understood that although the development work may be very complex and time-consuming, it is only a routine task for those skilled in the art who benefit from the content of this application.

[0016] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure and / or processing steps closely related to the scheme according to the present application are shown in the accompanying drawings, while other details that are not very relevant to the present application are omitted.

[0017] The disclosure below provides a plurality of different embodiments or examples to implement the present application. In order to simplify the disclosure of the present application, the parts and methods of specific examples are described below. Of course, they are merely examples, and the purpose is not to limit the present application. In the description of the embodiments of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0018] See also Figure 1 According to a first aspect of an embodiment of the present application, there is provided a core structure of a reactor, which comprises: a grid assembly, an auxiliary assembly 10, a stainless steel assembly 20, a fuel assembly 30, an adjustment assembly and an irradiation assembly 50, wherein a plurality of channels adjacent to each other are formed in the grid assembly; the auxiliary assembly 10 is arranged in the channel located at the outermost part of the plurality of channels; the stainless steel assembly 20 is closer to the channel in the middle of the plurality of channels than the auxiliary assembly 10; the fuel assembly 30 is arranged in the channel closer to the middle of the plurality of channels than the stainless steel assembly 20; the adjustment assembly is used to adjust the reactivity of the reactor, and the adjustment assembly is arranged in the channel around the channel where the fuel assembly 30 is arranged; the irradiation assembly 50 is used to be irradiated to produce the desired substance, and the irradiation assembly 50 is arranged in the channel located near the most central part of the plurality of channels, and in the channel adjacent to the fuel assembly 30, and in the channel between the channel where the fuel assembly 30 and the stainless steel assembly 20 are arranged; wherein the fuel in the fuel assembly 30 comprises an oxide fuel, and the fuel assembly 30 is arranged so that the total neutron injection rate of the core structure is not less than a predetermined value.

[0019] The predetermined value here can be, for example, 5×10 15 n / (cm 2 ·s), the core structure provided by the embodiment of the present application can provide more than 5.5×10 15 n / (cm 2 ·s) neutron injection rate, belonging to a high flux reactor. Further, using the NAS program to calculate, the calculated nominal value of the reactor balance cycle full stack breeding ratio provided in the embodiment of the present application is 0.30.

[0020] See also Figure 1 In the embodiment of the present application, the irradiation assembly 50 can occupy a single channel, or occupy 7 channels to form an irradiation loop. The irradiation loop can select a suitable cooling method as needed, such as lead-bismuth cooling, sodium cooling, air cooling, etc.

[0021] In the embodiment of the present application, the fuel assembly 30 can use uranium oxide ceramic fuel as the fuel pellets. The fuel assembly 30 uses a hexagonal outer sleeve and a built-in triangular arrangement of fuel pellets. The fuel pellets are radially positioned by spiral metal windings. The total length of the fuel assembly 30 is 2375 mm, and the effective density of the fuel pellets is 8.38 g / cm 3 The linear expansion coefficient of the core block is 1.1×10 -5 / ℃.

[0022] In the embodiments of the present application, the structural materials used in various components include austenitic steel (domestic code CN-1515) and iron horse steel (code CN-FMS).

[0023] In some embodiments, the fuel assembly 30 includes a first fuel assembly 31 and a second fuel assembly 32, the first fuel assembly 31 is arranged to be a channel closer to the middle of multiple channels than the second fuel assembly 32, and the enrichment of the second fuel assembly 32 is greater than that of the first fuel assembly 31, and the channel in which the first fuel assembly 31 is arranged is arranged on the outside of the channel in which the irradiation assembly 50 is arranged; the channel in which the irradiation assembly 50 is arranged is also arranged in the channel between the channels in which the first fuel assembly 31 and the second fuel assembly 32 are arranged, and the channel in which the irradiation assembly 50 is arranged is also arranged in the channel between the channels in which the second fuel assembly 32 and the stainless steel assembly are arranged.

[0024] The local power peak of the reactor will limit the total power output of the entire reactor, so the reactor needs to be power flattened to increase the total output power of the reactor. Therefore, the fuel assembly 30 can be divided into a first fuel assembly 31 and a second fuel assembly 32, and the first fuel assembly 31 closer to the hole in the middle of the multiple holes has a relatively lower enrichment to play a role in power flattening. In an embodiment of the present application, the U-235 enrichment of the first fuel assembly 32 and the second fuel assembly 32 can be 49.3% and 59.8%, respectively.

[0025] In some embodiments, the adjustment assembly includes a compensation rod 41, a safety rod 42, a passive rod 43 and an adjustment rod 44. The compensation rod 41, the safety rod 42 and the passive rod 43 are arranged at the junction of the channel where the first fuel assembly 31 is set and the channel where the second fuel assembly 32 is set. The adjustment rod 44 is arranged at the outer edge of the channel where the second fuel assembly 32 is set.

[0026] The absorbers of the compensation rod 41, the safety rod 42, the passive rod 43 and the adjustment rod 44 are all made of boron carbide core blocks. The absorber rod bundle moves in the outer sleeve of the adjustment component, and its radial positioning method adopts wire winding and upper and lower grid plate positioning.

[0027] In some embodiments, the channel of the auxiliary component 10 is arranged to form a C-shaped structure, and the channel at the opening 60 of the C-shaped structure is provided with a stainless steel component 20 .

[0028] In some embodiments, the compensation rods 41, safety rods 42 and passive rods 43 are evenly arranged along the circumference of the channel where the first fuel assembly 31 is set, wherein the channel where the passive rods 43 are set is set in the outermost channel of the channel where the second fuel assembly 32 is set.

[0029] In some embodiments, the number of holes for setting the safety rod 42 is two, which are respectively set in the holes between the holes for setting the first fuel assembly 31 and the second fuel assembly 32.

[0030] In some embodiments, the position of the hole where each adjustment rod 44 is located is set to form a triangle with one of the safety rods 42 and one of the compensation rods 41.

[0031] In some embodiments, the number of holes for setting the adjustment rods 44 is two, which are respectively set in the holes between the holes for setting the second fuel assembly 32 and the stainless steel assembly 20.

[0032] In some embodiments, the auxiliary component 10 includes a shielding member 11 and a storage member 12 , the storage member is used to store spent fuel, and the channel provided with the storage member 12 is arranged between the channels provided with the shielding member 11 .

[0033] In the embodiment of the present application, the fuel assembly 30 can be replaced in a "non-dumping" manner, that is, all the fuel assemblies 30 are irradiated to the irradiation assembly 50 at a fixed position in the grid assembly. After reaching the specified irradiation cycle, the spent fuel is unloaded into the storage component 12, and the new fuel assembly 30 is loaded into the corresponding position. During the entire burnup process, the positions of other components remain unchanged.

[0034] In some embodiments, the maximum neutron fluence rate obtained by the irradiation assembly 50 is different depending on the location of the hole.

[0035] See also Figures 2 to 3 , Figure 2 is a BOC maximum neutron fluence rate distribution diagram of a reactor provided according to an embodiment of the present application, Figure 3 is a distribution diagram of the maximum neutron flux rate of the EOC of the reactor provided in an embodiment of the present application, Figure 2 and Figure 3 The unit of the numbers is 1E15cm -2 s -1 .Depend on Figure 2 and Figure 3It can be seen that the maximum neutron injection rate of the whole reactor occurs at the center of the core, which is the location where the irradiation assembly is set. At the same time, from the overall trend, the farther the assembly is from the center of the core, the lower the neutron injection rate is. Therefore, the appropriate setting position can be selected according to the irradiation dose that the irradiation assembly needs to receive.

[0036] Figure 4 is a maximum radiation damage dose distribution diagram of each component within a cycle provided by an embodiment of the present application, Figure 4 The unit of the numbers is DPA / L. Figure 4 It can be seen that the maximum DPA occurs near the center of the fuel inner zone, and the DPA distribution in this area is relatively uniform. From the middle zone to the outside, the DPA gradually decreases. All irradiation positions in the core can provide an irradiation capacity of more than 1200 DPA / L per year.

[0037] In some embodiments, the critical rod position of the balance cycle can be obtained by iteratively calculating keff under different control rod positions of BOC and EOC. Table 1 shows the critical rod position of the balance cycle under different control rod positions, where the rod position is the height of the bottom of the control rod absorber relative to the lower end surface of the core fuel active area.

[0038] Table 1 Critical rod position of equilibrium cycle / cm

[0039]

[0040] An embodiment of the present application also provides a liquid metal cooled fast reactor, which includes the core structure provided by any embodiment of the present application.

[0041] Regarding the embodiments of the present application, it should also be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other to obtain new embodiments.

[0042] The above are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A core structure of a reactor, characterized in that: It includes: a grid assembly, wherein a plurality of channels adjacent to each other are formed in the grid assembly; An auxiliary component, wherein the auxiliary component is disposed in a most peripheral hole among the plurality of holes; a stainless steel component, the stainless steel component being closer to a hole in the middle of the plurality of holes than the auxiliary component; a fuel assembly disposed in a channel closer to a middle portion of the plurality of channels than the stainless steel assembly; A regulating assembly, the regulating assembly is used to regulate the reactivity of the reactor, the regulating assembly is arranged in a hole around the hole where the fuel assembly is arranged; An irradiation assembly, the irradiation assembly is used to be irradiated to produce a desired substance, the irradiation assembly is arranged in a hole located near the middle of the plurality of holes, in a hole adjacent to the fuel assembly, and in a hole between the fuel assembly and the hole of the stainless steel assembly; The fuel in the fuel assembly includes oxide fuel, and the fuel assembly is configured so that the total neutron injection rate of the core structure is not less than a predetermined value.

2. The core structure according to claim 1, characterized in that: The fuel assembly includes a first fuel assembly and a second fuel assembly, the first fuel assembly is arranged closer to a hole in the middle of the plurality of holes than the second fuel assembly, and the second fuel assembly has a greater enrichment than the first fuel assembly, The hole for arranging the first fuel assembly is arranged outside the hole for arranging the irradiation assembly; The channel for setting the irradiation assembly is also set in the channel between the channels for setting the first fuel assembly and the second fuel assembly, and the channel for setting the irradiation assembly is also set in the channel between the channels for setting the second fuel assembly and the stainless steel assembly.

3. The core structure according to claim 2, characterized in that: The adjustment assembly includes a compensation rod, a safety rod, a passive rod and an adjustment rod. The compensation rod, the safety rod and the passive rod are arranged at the junction of the channel where the first fuel assembly is arranged and the channel where the second fuel assembly is arranged. The adjustment rod is arranged at the outer edge of the channel where the second fuel assembly is arranged.

4. The core structure according to claim 1, characterized in that: The channel of the auxiliary component is arranged to form a C-shaped structure, and the channel at the opening of the C-shaped structure is provided with the stainless steel component.

5. The core structure according to claim 3, characterized in that: The compensating rods, the safety rods and the passive rods are evenly arranged along the circumference of the channel where the first fuel assembly is arranged, wherein the channel where the passive rods are arranged is arranged at the outermost channel of the channel where the second fuel assembly is arranged.

6. The core structure according to claim 5, characterized in that: The number of holes for setting the safety rod is two, which are respectively set in the holes between the holes for setting the first fuel assembly and the second fuel assembly.

7. The core structure according to claim 5, characterized in that: The position of the hole where each adjusting rod is located is arranged to form a triangle with one of the safety rods and one of the compensation rods.

8. The core structure according to claim 7, characterized in that: The number of the holes for setting the adjusting rod is two, which are respectively set in the holes between the holes for setting the second fuel assembly and the holes for setting the stainless steel assembly.

9. The core structure according to claim 1, characterized in that: The auxiliary component includes a shielding member and a storage member, wherein the storage member is used to store spent fuel, and the channel provided with the storage member is arranged between the channels provided with the shielding member.

10. The core structure according to any one of claims 1 to 9, characterized in that: The maximum neutron injection rate obtained by the irradiation assembly is different depending on the position of the hole.

11. A liquid metal cooled fast reactor, characterized in that ， It comprises the core structure according to any one of claims 1 to 10.

Images