Neutron source cold package with simplified structure, reactor-based cold neutron source and reactor

Abstract

The invention discloses a neutron source cold package with a simplified structure, a reactor-based cold neutron source and a reactor, and belongs to the technical field of nuclear. A neutron source cold package with a simplified structure comprises a moderator input pipe, a moderator output pipe, a cold package cavity and a coolant circulating pipeline. The moderator input pipe comprises an inflow section parallel to the moderator output pipe and a bent backflow section, the cold package cavity is connected with the backflow section, and the maximum cross section area of the cold package cavity covers the direction interval of neutron guide pipe arrangement. The coolant circulating pipeline comprises an input interlayer, an output interlayer and a cold bag cavity interlayer, and a vacuum interval is formed between the cold bag cavity interlayer and the input interlayer.

Description

Technical Field

[0001] The present invention belongs to the field of nuclear technology, and in particular relates to a neutron source cold pack with a simplified structure, a reactor-based cold neutron source and a reactor. Background Art

[0002] Cold neutron sources are a crucial foundation of neutron scattering technology. Their core component is a moderator circulation loop housed within a vacuum cylinder. This loop primarily consists of a heat exchanger, a cold pack, and associated piping. Within the cold pack, the moderator interacts with thermal neutrons, slowing them down into cold neutrons. The cold pack's structure has a crucial impact on the performance of the cold neutron source. Existing cold packs are complex and difficult to manufacture, resulting in inefficient moderator utilization and increased heat dissipation pressure due to redundant moderators. Therefore, providing a simplified cold pack for a neutron source would be beneficial for improving its efficiency. Summary of the Invention

[0003] The present invention aims to provide a neutron source cold pack with a simplified structure to improve the efficiency of the cold neutron source. The present invention also provides a reactor-based cold neutron source and a reactor.

[0004] According to an embodiment of one aspect of the present invention, a neutron source cold pack with a simplified structure is provided, comprising a moderator input pipe, a moderator output pipe, a cold pack cavity, and a coolant circulation pipeline, wherein: The moderator input pipe includes an inflow section and a reflux section, wherein the inflow section is arranged in parallel with the moderator output pipe, and the reflux section is arranged in a curved manner relative to the inflow section; The cold bag cavity is connected to the reflux section, the cross-sectional area of ​​the cold bag cavity is larger than the cross-sectional areas of the moderator input pipe and the moderator output pipe, and the maximum cross-sectional area of ​​the cold bag cavity covers the azimuth interval where the neutron guide tube is arranged; The coolant circulation pipeline includes an input interlayer, an output interlayer and a cold bag cavity interlayer. The input interlayer is configured as an interlayer sleeve surrounding the moderator input pipe, the output interlayer is configured as an interlayer sleeve surrounding the moderator output pipe, and the cold bag cavity interlayer is configured as an interlayer cavity surrounding the cold bag; a vacuum gap is formed between the cold bag cavity interlayer and the input interlayer.

[0005] Compared with the existing neutron source cold pack, this neutron source cold pack avoids the appearance of a three-layer thin-walled special-shaped structure by optimizing the structure of the cold pack cavity interlayer. On the one hand, it reduces the neutron loss caused by the multi-layer wall. On the other hand, by optimizing the cross-sectional shape of the cold pack, it improves the utilization efficiency of the moderator in the cold pack and reduces the cooling and heat dissipation requirements.

[0006] Furthermore, in some embodiments, the cold pack includes an upper connecting section, a lower connecting section, and a middle section, wherein the upper connecting section and the lower connecting section have gradually varying cross-sectional areas, and the upper connecting section protrudes toward the inflow section.

[0007] Furthermore, in some embodiments, the cross section of the middle section is a fan-shaped surface arranged around the inflow section.

[0008] Furthermore, in some embodiments, the input interlayer and the cross section of the moderator input tube form a concentric circle structure, and the output interlayer and the cross section of the moderator output tube form a concentric circle structure.

[0009] Furthermore, in some embodiments, the reflux section is connected to the bottom of the cold package cavity, and the moderator output pipe is connected to the top of the cold package cavity.

[0010] According to another embodiment of the present invention, a reactor-based cold neutron source is provided, which is arranged in a reactor. The reactor-based cold neutron source includes a cold pack, and the cold pack is configured as the neutron source cold pack with a simplified structure provided in any of the aforementioned embodiments.

[0011] Furthermore, in some embodiments, the reactor-based cold neutron source uses liquid hydrogen or deuterium as a moderator and helium as a coolant.

[0012] According to another embodiment of the present invention, a reactor is provided, comprising a reactor-based cold neutron source, wherein the reactor-based cold neutron source is configured as the reactor-based cold neutron source provided in any of the aforementioned embodiments and using a neutron source cold pack with a simplified structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the neutron source cold pack structure in one embodiment; Figure 2 This is a schematic diagram of the cross-sectional structure of the middle section of the cold pack in one embodiment; Figure 3 A schematic diagram of the cold pack structure of a neutron source in a pair of proportions; Figure 4 A pair of proportional diagrams showing the cross-sectional structure of the neutron source cold pack.

[0014] Meaning of the reference numerals: 1-Moderator inlet pipe; 11-inflow section; 12-reflux section; 2-cold ladle cavity; 21-lower connecting section; 22-middle section; 23-upper connecting section; 24-special-shaped cold ladle sandwich cavity; 3-Moderator outlet pipe; 4-input interlayer; 5-cold ladle cavity interlayer; 6-output interlayer; 7-coolant cavity; 71-connecting hole.

[0015] The purpose of the above-mentioned drawings is to provide a detailed explanation of the present invention so that those skilled in the art can understand the technical concepts of the present invention, and is not intended to limit the present invention. For the sake of simplicity, the above-mentioned drawings only schematically depict structures related to the technical features of the present invention and do not strictly depict the complete structure and all details according to actual scale. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below through specific embodiments with reference to the accompanying drawings.

[0017] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment herein. The appearance of such phrases in various places in the specification does not necessarily refer to the same embodiment, nor does it limit mutually exclusive independent or alternative embodiments. Those skilled in the art will appreciate that an embodiment herein may be combined with other embodiments as long as no structural conflicts arise.

[0018] In the description herein, unless otherwise specified or limited, the technical terms "installed," "connected," and "connected" should be understood broadly, and may refer to, for example, a movable connection, a fixed connection, or an integral connection. Those skilled in the art will understand the specific meanings of these terms in the embodiments of this application based on the specific circumstances.

[0019] In the description of this document, terms indicating orientation or positional relationships, such as "up", "down", "left", "right", "horizontal", "vertical", "height", "length", and "width", are intended to accurately describe the embodiments and simplify the description, but are not intended to limit the parts or structures involved to having a specific orientation, being installed or operated in a specific orientation, and should not be understood as limiting the embodiments in this document.

[0020] In the description herein, terms such as "first" and "second" are used only to distinguish different objects and should not be understood to indicate relative importance or to limit the quantity, specific order, or primary and secondary relationship of the described technical features. In the description herein, "plurality" means at least two.

[0021] Neutron scattering technology is widely used in industries such as military, energy, semiconductors, and new materials, and demand is increasing with technological advancement. Neutron scattering technology is based on cold neutron sources, and reactor-based cold neutron sources are currently the most stable and reliable cold neutron source solution. The basic principle of a reactor-based cold neutron source is to establish a region containing a cryogenic neutron moderator within the reactor's high- and medium-thermal neutron flux region. The cryogenic neutron moderator moderates thermal neutrons until they reach thermal equilibrium with the moderator. These neutrons are then transported out of the reactor through a neutron transport system, such as a neutron guide. The cold pack is the primary component that houses the cryogenic moderator and reacts with thermal neutrons. The structure of the cold pack has a critical impact on the performance and efficiency of the cold neutron source.

[0022] At present, the typical cold pack structure of reactor-based cold neutron source is as follows: Figure 3 and Figure 4As shown, the system comprises a moderator inlet pipe 1, a cold cladding cavity 2, a moderator outlet pipe 3, an inlet interlayer 4, a cold cladding cavity interlayer 5, an outlet interlayer 6, and a coolant cavity 7. The moderator flows from the moderator inlet pipe 1 into the cold cladding cavity 2, which is the primary area where the moderator moderates thermal neutrons. The cold cladding cavity 2 is comprised of a specially shaped cold cladding cavity 24 with an annular cross section. The space in the center of the specially shaped cold cladding cavity forms a coolant cavity 7. After moderating the thermal neutrons within the cold cladding cavity 2, the moderator flows out through the moderator outlet pipe 3 to the cold neutron source's heat exchanger (not shown). After cooling in the heat exchanger, the moderator flows back through the moderator inlet pipe 1, completing a thermosiphon cycle. Because energy exchange occurs during the moderator's moderation of thermal neutrons, the deposited nuclei in the moderator generate heat and increase in temperature, requiring a coolant to cool the moderator. The coolant flows into the coolant cavity 7 through the input interlayer 4. A connecting hole 71 is provided at the bottom of the special-shaped cold pack sandwich cavity 24. The coolant flows out of the coolant cavity 7 through the connecting hole 71, enters the cold pack cavity interlayer 5 on the outer peripheral side of the special-shaped cold pack sandwich cavity 24, and finally flows out through the output interlayer 6. In this cold pack structure, both the inner and outer surfaces of the special-shaped cold pack sandwich cavity 24 can be fully cooled by the coolant, so that the heat generated by the deposited nuclear energy can be effectively dissipated. The interlayer also forms a protective boundary to prevent moderator leakage.

[0023] However, if Figure 4 As shown, the special-shaped cold sandwich cavity 24 is a multi-layer nested structure, and its overall structure is very complex and difficult to manufacture. At the same time, the cross-section of the special-shaped cold sandwich cavity 24 is annular, but due to structural limitations, the distribution range of the neutron lead-out tube cannot cover the entire annular surface, which results in a considerable portion of the cold neutrons obtained by slowing down the moderator in the special-shaped cold sandwich cavity 24 cannot be utilized, but the nuclear heat still needs to be cooled by the coolant, which increases the heat dissipation pressure. Furthermore, the multi-layer wall structure itself will also lead to a decrease in the neutron injection rate.

[0024] In order to overcome the above-mentioned problems of the prior art, an embodiment of one aspect of the present invention provides a neutron source cold pack with a simplified structure, which can simplify the cold pack structure and improve the utilization efficiency of the moderator.

[0025] The neutron source cold pack structure is as follows Figure 1 and Figure 2 As shown, it includes a moderator input pipe 1, a moderator output pipe 3, a cold package cavity 2 and a coolant circulation pipeline.

[0026] The moderator inlet pipe 1 includes an inflow section 11 and a return section 12. The inflow section 11 is arranged parallel to the moderator outlet pipe 3, while the return section 12 is bent in a U-shape relative to the inflow section 11. A cold pack cavity 2 is connected to the return section 12. Its cross-sectional area is larger than that of the moderator inlet pipe 1 and the moderator outlet pipe 3, forming an expanded structure. The maximum cross-sectional area of ​​the cold pack cavity 2 can cover the azimuth range of the neutron guide arrangement.

[0027] The coolant circulation circuit includes an input interlayer 4, an output interlayer 6, and a cold-pack interlayer 5. The input interlayer 4 is a jacketed tube surrounding the moderator input pipe, the output interlayer 6 is a jacketed tube surrounding the moderator output pipe, and the cold-pack interlayer 5 is a jacketed cavity surrounding the cold-pack cavity 2. A vacuum barrier exists between the cold-pack interlayer 5 and the input interlayer 4. In a preferred embodiment, the input interlayer 4 forms a concentric circle with the cross section of the moderator input pipe 1, and the output interlayer 6 also forms a concentric circle with the cross section of the moderator output pipe 3.

[0028] In a preferred embodiment, the cold ladle 2 includes an upper connecting section 23 disposed at the top, a lower connecting section 21 disposed at the bottom, and a middle section 22 disposed between the upper and lower connecting sections 23, 21. The upper and lower connecting sections 23, 21 have gradually varying cross-sectional areas, with the upper connecting section 23 protruding toward the inflow section 11. Furthermore, the cross-sectional shape of the middle section 22 is a sector-shaped surface disposed around the inflow section 11. The lower connecting section 21 of the cold ladle 2 is connected to the reflux section 12 of the moderator inlet pipe 1, while the upper connecting section 23 is connected to the moderator outlet pipe 3.

[0029] The neutron source cold pack has a simple structure, avoiding complex, multiple nested structures and effectively reducing manufacturing complexity. Due to the reduced number of nested structures, the number of walls that thermal neutrons need to pass through for contact with the moderator is reduced, thereby correspondingly improving the thermal neutron fluence rate. Furthermore, the overall structure of the cold pack cavity 2 not only aligns with the vacuum cylinder and the neutron guide tube layout, increasing neutron flux, but also improves the structural strength of the cold pack cavity 2 and reduces the risk of damage. Furthermore, since the cross-sectional shape of the cold pack cavity 2 replaces the circular shape used in the prior art with a fan-shaped cross-section, the distribution of the moderator involved in moderating thermal neutrons is more consistent with the spatial distribution of the neutron guide tube, reducing moderator volume and improving moderator utilization efficiency. With less moderator producing ineffective heat, the cold pack's heat dissipation capacity is further optimized. Furthermore, the simplified structure of the cold pack cavity 2 reduces flow resistance during the circulation of the moderator and coolant, ensuring smoother flow of the moderator and coolant, and reducing flow-induced vibration during circulation, further enhancing the reliability of the cold neutron source during long-term service.

[0030] According to another embodiment of the present invention, a reactor-based cold neutron source is provided, comprising a vacuum cylinder, a neutron guide tube, a heat exchanger, and a cold pack. The cold pack and heat exchanger are placed within the vacuum cylinder, wherein the cold pack utilizes the simplified neutron source cold pack provided in any of the aforementioned embodiments. The reactor-based cold neutron source uses liquid hydrogen or deuterium as a moderator and cryogenic helium as a coolant. A circulation pipeline is established between the heat exchanger and the cold pack. Coolant flows from outside the reactor into the cooling device for heat exchange and then flows out of the reactor. Moderator flowing out of the cold pack undergoes sufficient heat exchange with the coolant within the cooling device, then cools and flows back to the cold pack, thereby ensuring that the cold pack remains in a stable low-temperature state. Thermal neutrons are cooled by the moderator in the cold pack to become cold neutrons. These are then collected by the neutron guide tube and output outside the reactor for use in various neutron experiments utilizing the cold neutron source, such as neutron diffraction.

[0031] An embodiment of another aspect of the present invention provides a reactor, in which one or more reactor-based cold neutron sources are provided. The reactor-based cold neutron sources are the reactor-based cold neutron sources provided in any of the aforementioned embodiments.

[0032] The purpose of the above embodiments is to provide a further detailed description of the present invention in conjunction with the accompanying drawings so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the present invention, optimization or equivalent replacement of the technical features involved, as well as combination of implementation methods in different embodiments without conflict of structure and principle, all fall within the scope of protection of the present invention.

Claims

1. A neutron source cold pack with a simplified structure, comprising a moderator input pipe, a moderator output pipe, a cold pack cavity, and a coolant circulation pipeline, wherein the cold pack cavity is connected between the moderator input pipe and the moderator output pipe, and is characterized in that: The moderator input pipe includes an inflow section and a reflux section, wherein the inflow section is arranged in parallel with the moderator output pipe, and the reflux section is arranged in a curved manner relative to the inflow section; The cold bag cavity is connected to the reflux section, the cross-sectional area of ​​the cold bag cavity is larger than the cross-sectional areas of the moderator input pipe and the moderator output pipe, and the maximum cross-sectional area of ​​the cold bag cavity covers the azimuth interval where the neutron guide tube is arranged; The coolant circulation pipeline includes an input interlayer, an output interlayer and a cold bag cavity interlayer. The input interlayer is configured as an interlayer sleeve surrounding the moderator input pipe, the output interlayer is configured as an interlayer sleeve surrounding the moderator output pipe, and the cold bag cavity interlayer is configured as an interlayer cavity surrounding the cold bag; a vacuum gap is formed between the cold bag cavity interlayer and the input interlayer.

2. The simplified neutron source cold pack according to claim 1, characterized in that: The cold pack cavity comprises an upper connecting section, a lower connecting section and a middle section, wherein the upper connecting section and the lower connecting section have gradually varying cross-sectional areas, and the upper connecting section protrudes toward the inflow section.

3. The simplified neutron source cold pack according to claim 2, characterized in that: The cross section of the middle section is a fan-shaped surface arranged around the inflow section.

4. The simplified neutron source cold pack according to claim 1, 2 or 3, characterized in that: The input interlayer and the cross section of the moderator input tube form a concentric circle structure, and the output interlayer and the cross section of the moderator output tube form a concentric circle structure.

5. The simplified neutron source cold pack according to claim 1, 2 or 3, characterized in that: The reflux section is connected to the bottom of the cold package cavity, and the moderator output pipe is connected to the top of the cold package cavity.

6. A reactor-based cold neutron source, arranged in a reactor, comprising a cold pack, characterized in that: The cold pack is configured as a neutron source cold pack with a simplified structure as claimed in any one of claims 1 to 5.

7. The reactor-based cold neutron source according to claim 6, characterized in that: The reactor-based cold neutron source uses liquid hydrogen or deuterium as a moderator and helium as a coolant.

8. A reactor comprising a reactor-based cold neutron source, characterized in that: The reactor-based cold neutron source is configured as the reactor-based cold neutron source as described in claim 6 or 7.

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