Split type reactor-based cold neutron source and reactor

Abstract

The invention discloses a split type reactor-based cold neutron source and a reactor, and belongs to the technical field of nuclear. The split type reactor-based cold neutron source is arranged in a reactor and comprises a vacuum cylinder, a coolant circulating assembly and a cold package assembly, wherein the vacuum cylinder is provided with a vacuum cavity with an annular cross section; the coolant circulating assembly comprises a coolant input pipe and a coolant output pipe, and is communicated to a coolant cavity defined by the inner wall of the vacuum cylinder for inputting and outputting a coolant; the cold package assembly is of a single-layer wall body structure and is arranged in the coolant cavity, and the cold package assembly is cooled through a coolant. The cold neutron source is simple in structure, good in cooling effect, convenient to overhaul and maintain, capable of independently maintaining and replacing the cold package assembly, and high in reliability.

Description

Technical Field

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

[0002] Neutron scattering technology is a widely used advanced analytical technique with important applications in energy, military industry, advanced materials, and other fields. Cold neutron sources are one of the key foundations of neutron scattering technology. Their principle is to construct a localized region of ultra-low-temperature medium with excellent neutron moderation performance within a high-flux region of thermal neutrons, and then extract the moderated cold neutrons. However, existing cold neutron source devices typically use a complex double-layer piping structure, which is not only difficult to manufacture, but also difficult to maintain and inspect, resulting in insufficient long-term reliability and safety. Therefore, providing a reactor-based cold neutron source with a simplified structure is of positive significance for reducing the manufacturing and maintenance costs of neutron sources and improving reliability. Summary of the Invention

[0003] The present invention aims to provide a split reactor-based cold neutron source, simplify the device structure and improve reliability. The present invention also provides a reactor.

[0004] According to an embodiment of one aspect of the present invention, a split-type reactor-based cold neutron source is provided, which is installed in a reactor. The reactor-based cold neutron source includes: a vacuum cylinder, a coolant circulation assembly, and a cold pack assembly; wherein: The vacuum cylinder comprises an inner wall and an outer wall, wherein the inner wall and the outer wall define a vacuum cavity having an annular cross section; The coolant circulation assembly includes a coolant input pipe and a coolant output pipe, wherein the coolant input pipe and the coolant output pipe are connected to a coolant cavity defined by the inner wall of the vacuum cylinder, and the coolant flows into the coolant cavity through the coolant input pipe and flows out through the coolant output pipe; The cold pack assembly is disposed in the coolant cavity and is configured as a single-wall structure to allow the coolant to cool the cold pack assembly.

[0005] The vacuum cavity of the vacuum cylinder in the reactor-based cold neutron source is configured as an annular sandwich between the inner wall and the outer wall. The cold pack assembly adopts a double-layer wall structure. The entire area between the wall of the cold pack assembly and the inner wall of the vacuum cavity serves as a coolant cavity for accommodating coolant. The coolant circulation loop is separated from the pipeline of the cold pack assembly, avoiding the use of double-layer pipelines with a complex structure, effectively simplifying the complexity of the cold neutron source structure, improving the reliability of the device, and facilitating the maintenance of the cold pack assembly. Due to the increase in the volume of the coolant cavity, the cooling performance of the cold pack assembly is also further enhanced.

[0006] Furthermore, in some embodiments, the cold pack assembly contains a moderator, and the cold pack assembly includes a cold pack, a heat exchanger and a moderator input pipe. A siphon circulation loop is formed between the cold pack and the heat exchanger, and the moderator input pipe is used to input the moderator.

[0007] Furthermore, in some embodiments, a sealing flange is further included, which is arranged at the end of the vacuum cylinder to close the coolant cavity, and the sealing flange is provided with through holes to allow the coolant input pipe, the coolant output pipe and the moderator input pipe to pass through.

[0008] Furthermore, in some embodiments, the vacuum cylinder further includes a vacuum tube interface, which is connected to the vacuum chamber. The vacuum tube interface is arranged on a side wall of the vacuum cylinder, and the vacuum tube does not pass through the sealing flange.

[0009] By arranging the vacuum tube interface on the side wall of the vacuum cylinder, the number of pipelines passing through the sealing flange is reduced, thereby reducing the maintenance difficulty of the cold neutron source.

[0010] Furthermore, in some embodiments, the cold pack assembly further includes an ascending pipe and a descending pipe, wherein the ascending pipe is connected from the top of the cold pack to the top of the heat exchanger, and the descending pipe is connected from the bottom of the heat exchanger to the bottom of the cold pack.

[0011] Furthermore, in some embodiments, the cold pack, the upward pipe, and the downward pipe are made of aluminum alloy and connected by welding.

[0012] Aluminum alloy has good neutron permeability and strong radiation resistance. At the same time, for single-wall cold pack components, if local pipelines are damaged, it is easy to carry out repair welding.

[0013] Furthermore, in some embodiments, the vacuum cylinder includes a tube body and a sealing head, the tube body is configured in a cylindrical shape, and the sealing head is configured in a hemispherical shape.

[0014] The cylindrical tube body has a simple structure, which increases the coolant chamber volume and facilitates maintenance.

[0015] Furthermore, in some embodiments, in the coolant cavity, the port of the coolant input pipe is arranged above the port of the coolant output pipe.

[0016] Furthermore, in some embodiments, the coolant is helium, and the moderator in the cold pack assembly is liquid hydrogen or hydrogen isotope.

[0017] According to another embodiment of the present invention, a reactor is provided, which includes a reactor-based cold neutron source. The reactor-based cold neutron source adopts the reactor-based cold neutron source provided in any of the aforementioned embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the reactor-based cold neutron source structure in one embodiment.

[0019] Meaning of the reference numerals: 1-vacuum cylinder; 2-coolant cavity; 3-coolant inlet pipe; 4-heat exchanger; 5-down pipe; 6-cold pack; 7-up pipe; 8-vacuum tube interface; 9-sealing flange; 10-moderator inlet pipe; 11-coolant outlet pipe.

[0020] 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

[0021] The present invention will be further described in detail below through specific embodiments with reference to the accompanying drawings.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] Neutron beams have good penetration, sensitivity to light elements, and special magnetic properties, so neutron scattering technology plays an irreplaceable role in the research of magnetic materials, crystal structure characterization, material defect and stress analysis, and is widely used in energy, chemical industry, materials, aerospace and many other industries. The basis of neutron scattering technology is a cold neutron source device, and its basic principle is to build a region with good neutron moderation performance in the high flux area of thermal neutrons, in which the thermal neutrons are collided and moderated in the medium until they reach thermal equilibrium with the low-temperature medium to become cold neutrons, and then transported to the far-end neutron spectrometer or other neutron physics test device by a neutron transport system such as a neutron guide tube, to carry out various neutron beam application tests. The super-low-temperature medium, and the low-temperature moderator of the cold neutron source, is usually liquid hydrogen or liquid hydrogen isotopes such as liquid deuterium. In the neutron moderation process, the moderator absorbs heat and warms up. To avoid the accumulation of heat causing the moderator to vaporize, a coolant needs to be provided to further cool the moderator.

[0027] To ensure that the moderator remains in a low-temperature state and at the same time to build a safety boundary for the cold neutron source to ensure that the abnormal or accident conditions of the cold neutron source will not threaten the safety of the reactor, the core system of the cold neutron source is generally installed in a vertical support tube located in the reflector of the reactor. The existing core system of the cold neutron source includes a vacuum shaft as an external boundary and a moderator circulation system. The moderator circulation system adopts a double-layer pipe structure, and the cold pack containing the moderator, the circulation pipe and the heat sink all adopt a double-layer structure. The moderator circulation system has a double-layer wall, the inner layer contains the moderator, and the interlayer between the two layers contains flowing coolant (such as low-temperature helium), which is used to cool the moderator and prevent the moderator from leaking. However, the double-layer structure of the moderator circulation system is very complex, has a high manufacturing difficulty, and has poor maintainability. Once a local defect or damage occurs, the entire system must be scrapped. The complexity of the structure also increases the risk of defects and damage to the connection structure such as the weld, which affects the overall reliability of the cold neutron source. The limited coolant that can be contained in the interlayer structure also restricts the further improvement of the heat dissipation capacity.

[0028] To overcome the deficiencies of the prior art, an embodiment of one aspect of the present application provides a split-type reactor-based cold neutron source. In the reactor-based cold neutron source, the moderator circulation system adopts a single-layer wall structure, which simplifies the structure and improves the reliability. Specifically, the structure of the split-type reactor-based cold neutron source is as shown in Figure 1 The reactor-based cold neutron source includes a vacuum cylinder 1, a coolant circulation assembly and a cold pack assembly.

[0029] Specifically, the vacuum cylinder 1 includes an inner wall and an outer wall, which define a vacuum chamber with an annular cross-section. The inner side of the inner wall of the vacuum cylinder 1 defines a coolant chamber 2. A sealing flange 9 is provided at the end of the vacuum cylinder 1. A coolant inlet pipe 3 and a coolant outlet pipe 11 pass through the sealing flange 9 and into the coolant chamber 2. The coolant (cold helium) flows into the coolant inlet pipe 3, fills the coolant chamber 2, and flows out of the coolant outlet pipe 11. In a preferred embodiment, the vacuum cylinder 1 includes a cylindrical tube body and a hemispherical head, and the coolant chamber 2 has a circular cross-section. In a further preferred embodiment, the port of the coolant inlet pipe 3 is positioned higher than the port of the coolant outlet pipe 11 to fully utilize the coolant's convective heat transfer and further improve the cooling effect. In a preferred embodiment, the coolant is high-pressure helium.

[0030] The entire cold pack assembly is housed within the coolant chamber 2 and includes a cold pack 6, a heat exchanger 4, a descending pipe 5 connecting the cold pack 6 and the heat exchanger 4, an ascending pipe 7, and a moderator inlet pipe 10 for injecting moderator. The cold pack 6, located at the bottom of the coolant chamber 2, serves as the primary area for thermal neutron moderation. A moderator siphon circulation loop is formed between the cold pack 6 and the heat exchanger 4. The moderator (typically liquid hydrogen or deuterium) reacts with neutrons within the cold pack 6, raising its temperature. Through thermal convection, the moderator enters the top of the heat exchanger 4 through the ascending pipe 7 connected to the top of the cold pack 6. The heat exchanger 4, with its grid-like structure, exchanges heat with the helium gas within the coolant chamber, cooling the gas. The cooled moderator then flows back through the descending pipe 5 at the bottom of the heat exchanger 4 to the bottom of the cold pack 6, completing the circulation cycle.

[0031] In a preferred embodiment, the cold pack 6 and the up-going pipe 7 and the down-going pipe 5 are configured as an aluminum alloy welded structure. Aluminum alloy has good neutron permeability and radiation resistance, which can improve the service life and reliability of the cold pack assembly.

[0032] Compared to a cold neutron source with a sandwich structure, the coolant chamber 2 in the above-described embodiment has a larger internal volume, allowing a larger amount of coolant to participate in cooling the cold pack assembly, effectively improving the cooling effect. Furthermore, because the wall of the cold pack assembly adopts a single-layer structure, the overall structural complexity is effectively simplified compared to a double-layer cold neutron source, reducing manufacturing difficulty and reducing the probability of damage by only half that of a double-layer cold neutron source. Leaks or defects in welds and other locations are easily detected and repaired through methods such as patch welding. However, cold neutron sources, which periodically experience temperature fluctuations during service, are prone to damage. Conventional double-layer cold neutron sources are integral structures. Once defects or damage occur, they cannot be repaired and must be scrapped as a whole. In contrast, the cold neutron source provided in the present embodiment has a split cold pack assembly housed within the cylindrical coolant chamber 2, making it easy to disassemble and replace the cold pack assembly separately.

[0033] In a preferred embodiment, the vacuum tube interface 8 used to maintain the vacuum level within the vacuum cylinder 1 is disposed on the sidewall of the vacuum cylinder 1, so that the vacuum tube interface 8 does not pass through the sealing flange 9. By locating the vacuum tube interface 8 on the sidewall of the vacuum cylinder 1, the number of pipelines extending through the sealing flange 9 is reduced, thereby improving the reliability of the sealing flange 9 itself. Furthermore, the maintenance and replacement of equipment within the cold neutron source reactor is considered radioactive, and the more pipelines that are removed and installed, the higher the radiation safety risk. By locating the vacuum tube interface 8 on the sidewall, subsequent maintenance and upgrades of equipment within the cold neutron source reactor do not involve the vacuum cylinder 1, and under normal circumstances, there is no need to remove or install vacuum pipelines, effectively reducing the risk of radioactive operations.

[0034] An embodiment of another aspect of the present invention provides a reactor, which includes a reactor-based cold neutron source. The reactor-based cold neutron source adopts the reactor-based cold neutron source provided in any of the aforementioned embodiments.

[0035] 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 causing structural or principle conflicts, all fall within the scope of protection of the present invention.

Claims

1. A split-type reactor-based cold neutron source, arranged in a reactor, characterized in that: include: A vacuum cylinder, a coolant circulation assembly, and a cold pack assembly; wherein: The vacuum cylinder comprises an inner wall and an outer wall, wherein the inner wall and the outer wall define a vacuum cavity having an annular cross section; The coolant circulation assembly includes a coolant input pipe and a coolant output pipe, wherein the coolant input pipe and the coolant output pipe are connected to a coolant cavity defined by the inner wall of the vacuum cylinder, and the coolant flows into the coolant cavity through the coolant input pipe and flows out through the coolant output pipe; The cold pack assembly is disposed in the coolant cavity and is configured as a single-wall structure to allow the coolant to cool the cold pack assembly.

2. The split-type reactor-based cold neutron source according to claim 1, characterized in that: The cold pack assembly contains a moderator, and the cold pack assembly includes a cold pack, a heat exchanger and a moderator input pipe. A siphon circulation loop is formed between the cold pack and the heat exchanger, and the moderator input pipe is used to input the moderator.

3. The split-type reactor-based cold neutron source according to claim 2, characterized in that: It also includes a sealing flange, which is arranged at the end of the vacuum cylinder to close the coolant cavity. The sealing flange is provided with through holes to allow the coolant input pipe, the coolant output pipe and the moderator input pipe to pass through.

4. The split-type reactor-based cold neutron source according to claim 3, characterized in that: The vacuum cylinder further includes a vacuum tube interface, which is connected to the vacuum chamber. The vacuum tube interface is arranged on the side wall of the vacuum cylinder, and the vacuum tube does not pass through the sealing flange.

5. The split-type reactor-based cold neutron source according to claim 2, 3 or 4, characterized in that: The cold pack assembly further includes an ascending pipe and a descending pipe, wherein the ascending pipe is connected from the top of the cold pack to the top of the heat exchanger, and the descending pipe is connected from the bottom of the heat exchanger to the bottom of the cold pack.

6. The split-type reactor-based cold neutron source according to claim 5, characterized in that: The cold pack, the upward pipe and the downward pipe are made of aluminum alloy and connected by welding.

7. The split-type reactor-based cold neutron source according to any one of claims 1 to 4, characterized in that: The vacuum cylinder comprises a tube body and a sealing head, wherein the tube body is configured in a cylindrical shape and the sealing head is configured in a hemispherical shape.

8. The split-type reactor-based cold neutron source according to any one of claims 1 to 4, characterized in that: In the coolant cavity, the port of the coolant input pipe is arranged above the port of the coolant output pipe.

9. The split-type reactor-based cold neutron source according to any one of claims 1 to 4, characterized in that: The coolant is helium, and the moderator in the cold pack assembly is liquid hydrogen or hydrogen isotope.

10. A reactor, characterized in that: The reactor includes a reactor-based cold neutron source, and the reactor-based cold neutron source is configured as a split reactor-based cold neutron source as described in any one of claims 1 to 9.

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