Split pile-based cold neutron source and reactor

Abstract

The application relates to a split type reactor base cold neutron source and reactor, belonging to the nuclear technology field. The split type reactor base cold neutron source is arranged in a reactor and comprises a vacuum cylinder, a coolant circulating assembly and a cold package assembly. The vacuum cylinder has a vacuum cavity with a ring-shaped cross section. The coolant circulating assembly comprises a coolant input pipe and a coolant output pipe which are communicated to a coolant cavity defined by the inner wall of the vacuum cylinder for coolant input and output. The cold package assembly is a single-layer wall structure and is arranged in the coolant cavity and cooled by the coolant. The cold neutron source has the advantages of simple structure, good cooling effect, convenience in maintenance and repair, high reliability and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nuclear technology, and particularly relates to a split type reactor-based cold neutron source and a reactor. BACKGROUND

[0002] The neutron scattering technology is an advanced analysis technical scheme with wide application, and has important application in the fields of energy, military industry, advanced materials and the like. The cold neutron source is one of important foundations of the neutron scattering technology, and the principle thereof is to construct a local region of an ultralow-temperature medium with good neutron moderation performance in a high-flux region of thermal neutrons, and then to guide out the moderated cold neutrons. However, the existing cold neutron source device usually adopts a double-layer pipe structure with complex structure, which is not only difficult to manufacture, but also difficult to maintain and detect, and has insufficient reliability and safety in long-term use. Therefore, it is of positive significance to provide a reactor-based cold neutron source with simplified structure for reducing the manufacturing and maintenance costs of the neutron source and improving the reliability. SUMMARY

[0003] The present application aims to provide a split type reactor-based cold neutron source with simplified device structure and improved reliability. The present application also provides a reactor.

[0004] According to an embodiment of one aspect of the present application, a split type reactor-based cold neutron source is provided, which is arranged in a reactor. The reactor-based cold neutron source comprises a vacuum cylinder, a coolant circulation assembly and a cold package assembly, wherein:

[0005] The vacuum cylinder comprises an inner wall and an outer wall, and the inner wall and the outer wall define a vacuum cavity with annular cross section;

[0006] The coolant circulation assembly comprises a coolant input pipe and a coolant output pipe, and 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;

[0007] The cold package assembly is arranged in the coolant cavity and is configured as a single-layer wall structure to allow the coolant to cool the cold package assembly.

[0008] The vacuum cavity of the vacuum cylinder in the reactor-based cold neutron source is arranged as an annular interlayer between the inner wall and the outer wall, and the cold package assembly adopts a single-layer wall structure. The wall of the cold package assembly and the inner wall of the vacuum cavity as a whole form a coolant cavity for containing the coolant, and the coolant circulation loop and the pipeline of the cold package assembly are separated, avoiding the use of a double-layer pipe with complex structure, effectively simplifying the complexity of the structure of the cold neutron source, improving the reliability of the device, and facilitating the maintenance of the cold package assembly. Due to the increase in the volume of the coolant cavity, the cooling performance of the cold package assembly is further enhanced.

[0009] Further, in some embodiments, the cold pack assembly contains a moderator, and the cold pack assembly comprises 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.

[0010] Further, in some embodiments, a sealing flange is further included, the sealing flange is arranged at the end of the vacuum cylinder to close the coolant cavity, and a through hole is arranged on the sealing flange to allow the coolant input pipe, the coolant output pipe, and the moderator input pipe to pass through.

[0011] Further, in some embodiments, the vacuum cylinder further comprises a vacuum pipe interface, the vacuum pipe interface is connected to the vacuum cavity, and the vacuum pipe interface is arranged on the side wall of the vacuum cylinder, and the vacuum pipe does not pass through the sealing flange.

[0012] By arranging the vacuum pipe interface on the side wall of the vacuum cylinder, the number of pipes passing through the sealing flange is reduced, and the maintenance difficulty of the cold neutron source is reduced.

[0013] Further, in some embodiments, the cold pack assembly further comprises an uplink pipe and a downlink pipe, the uplink pipe is connected from the top of the cold pack to the top of the heat exchanger, and the downlink pipe is connected from the bottom of the heat exchanger to the bottom of the cold pack.

[0014] Further, in some embodiments, the cold pack, the uplink pipe, and the downlink pipe are made of aluminum alloy and are connected by welding.

[0015] The neutron permeability of aluminum alloy is good, and the radiation resistance is strong. At the same time, for a single-layer-wall cold pack assembly, if local pipes are damaged, repair welding can be easily performed.

[0016] Further, in some embodiments, the vacuum cylinder comprises a tube body and a head, the tube body is configured in a cylindrical shape, and the head is configured in a hemispherical shape.

[0017] The cylindrical tube body structure is simple, and the coolant cavity volume is increased while maintenance is facilitated.

[0018] Further, in some embodiments, in the coolant cavity, the port of the coolant input pipe is arranged above the port of the coolant output pipe.

[0019] Further, in some embodiments, the coolant is helium, and the moderator in the cold pack assembly is liquid hydrogen or hydrogen isotope.

[0020] According to an embodiment of another aspect of the present application, a reactor is provided, the reactor comprises a reactor-based cold neutron source, and the reactor-based cold neutron source is the reactor-based cold neutron source provided in any of the foregoing embodiments.BRIEF DESCRIPTION OF DRAWINGS BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Figure 1 is a schematic diagram of a structure of a reactor for a cold neutron source in an embodiment.

[0022] Meaning of reference signs:

[0023] 1 - vacuum vessel; 2 - coolant chamber; 3 - coolant inlet pipe; 4 - heat exchanger; 5 - downcomer; 6 - cold trap; 7 - upcomer; 8 - vacuum vessel connection; 9 - sealing flange; 10 - moderator inlet pipe; 11 - coolant outlet pipe.

[0024] The above drawings are intended to provide a detailed description of the present application, so that those skilled in the art can understand the technical concept of the present application, and are not intended to limit the present application. In order to express concisely, the above drawings only schematically draw the structures related to the technical features of the present application, and do not strictly draw the complete structures and all details according to the actual proportions. DETAILED DESCRIPTION

[0025] The present application will be further described in detail through specific embodiments combined with the drawings.

[0026] The phrase "embodiment" mentioned herein means that the specific features, structures or properties described in combination with the embodiments can be contained in at least one embodiment herein. The phrase appears at various positions in the specification does not necessarily refer to the same embodiment, nor is limited to mutually exclusive or alternative embodiments. Those skilled in the art should understand that the embodiments herein can be combined with other embodiments without structural conflicts.

[0027] In the description herein, unless otherwise explicitly specified and limited, the technical terms "mount", "connect", "connect" and the like should be understood broadly, for example, can be movable connection, or fixed connection or integral. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0028] In the description herein, the terms indicating the orientation or position relationship such as "upper", "lower", "left", "right", "transverse", "vertical", "height", "length", "width" and the like are intended to accurately describe the embodiments and simplify the description, and are not limited to the parts or structures involved. Must have a specific orientation, be installed or operated in a specific orientation, and cannot be understood as a limitation on the embodiments herein.

[0029] In the description herein, the terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating relative importance or limiting the number, specific order or primary and secondary relationship of the described technical features. In the description herein, the meaning of "multiple" is at least two.

[0030] 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 many industries such as energy, chemical industry, materials, aerospace, etc. 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 region of thermal neutrons, in which the thermal neutrons collide and slow down in the medium until they reach thermal equilibrium with the low-temperature medium to become cold neutrons, and then are transported to the far-end neutron spectrometer or other neutron physics test device by the neutron transport system such as neutron conduit, 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 isotope such as liquid deuterium. In the neutron moderation process, the moderator absorbs heat and warms up. To avoid the accumulation of heat causing the vaporization of the moderator, a coolant needs to be provided to further cool the moderator.

[0031] 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 layer 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 wall 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 leakage of the moderator. However, the double-layer structure of the moderator circulation system is very complex, has high manufacturing difficulty, and poor maintainability. Once a local defect or damage occurs, the whole must be scrapped. The complexity of the structure also increases the connection structure such as the weld, further increasing the risk of defects and affecting the reliability of the whole cold neutron source. The limited coolant that can be contained in the interlayer structure also restricts the further improvement of the heat dissipation capacity.

[0032] 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.

[0033] Specifically, the vacuum cylinder 1 comprises an inner wall and an outer wall, which define a vacuum cavity in the shape of a ring in cross section; the inner side of the inner wall of the vacuum cylinder 1 defines a coolant cavity 2, the end of the vacuum cylinder 1 is provided with a sealing flange 9, and a coolant input pipe 3 and a coolant output pipe 11 pass through the sealing flange 9 and enter the coolant cavity 2, coolant (low-temperature helium) flows into the coolant cavity 2 from the coolant input pipe 3, fills the coolant cavity 2, and flows out from the coolant output pipe 11. In a preferred embodiment, the vacuum cylinder 1 comprises a cylindrical body and a hemispherical head, and the coolant cavity 2 is circular in cross section. In a further preferred embodiment, the port position of the coolant input pipe 3 is higher than that of the coolant output pipe 11, so as to further improve the cooling effect by making full use of the convective heat transfer of the coolant. In a preferred embodiment, the coolant is high-pressure helium.

[0034] The cold pack assembly is arranged in the coolant cavity 2 as a whole and comprises a cold pack 6, a heat exchanger 4, a downcomer 5 connecting the cold pack 6 and the heat exchanger 4, an upcomer 7, and a moderator input pipe 10 for injecting a moderator. The cold pack 6 is arranged at the bottom of the coolant cavity 2 and is the main area for thermal neutron moderation; a moderator siphon circulation loop is formed between the cold pack 6 and the heat exchanger 4. The moderator (usually liquid hydrogen or deuterium) is heated in the cold pack 6 by reaction with neutrons, and under the action of thermal convection, enters the top of the heat exchanger 4 through the upcomer 7 connected to the top of the cold pack 6; the heat exchanger 4 has a grid-like structure and exchanges heat with the helium in the coolant cavity to be cooled; the cooled moderator flows back to the bottom of the cold pack 6 through the downcomer 5 at the bottom of the heat exchanger 4, completing the circulation.

[0035] In a preferred embodiment, the cold pack 6 and the upcomer 7 and the downcomer 5 are configured as an aluminum alloy welded structure, and the aluminum alloy has good neutron transparency and irradiation resistance, which can improve the service life and reliability of the cold pack assembly.

[0036] Compared with the cold neutron source with a sandwich structure, the coolant cavity 2 in the above embodiment has a larger volume, which can enable a larger amount of coolant to participate in the cooling and temperature reduction of the cold pack assembly, effectively improving the cooling effect. At the same time, since the wall of the cold pack assembly adopts a single-layer structure, the complexity of the overall structure is effectively simplified compared with the double-layer structure cold neutron source, the manufacturing difficulty is reduced, and the damage probability is only half of that of the double-layer structure cold neutron source. If leakage or defects occur at positions such as welds, they are easy to detect and repair by repair welding. The cold neutron source needs to be periodically subjected to temperature alternation during service, which is prone to damage. The conventional double-layer structure cold neutron source is an integrated structure, which cannot be repaired once defects or damage occur and can only be scrapped as a whole; the cold neutron source provided in the embodiments of the present application has a cold pack assembly as a split structure accommodated in the cylindrical coolant cavity 2, which is easy to individually disassemble and replace the cold pack assembly.

[0037] In the preferred embodiment, the vacuum pipe interface 8 for maintaining the vacuum degree in the vacuum cylinder 1 is arranged on the side wall of the vacuum cylinder 1, so that the vacuum pipe interface 8 does not pass through the sealing flange 9. By arranging the vacuum pipe interface 8 on the side wall of the vacuum cylinder 1, the number of pipelines passing through the sealing flange 9 is reduced, and the reliability of the sealing flange 9 itself is improved. At the same time, the maintenance and replacement work of the cold neutron source in-vessel equipment is a radioactive work, and the more pipelines that need to be disassembled and installed, the higher the radiation safety risk will be; by arranging the vacuum pipe interface 8 on the side wall, the later maintenance and upgrading work of the cold neutron source in-vessel equipment does not involve the vacuum cylinder 1, and the vacuum pipeline does not need to be disassembled and installed under normal circumstances, thereby effectively reducing the risk of radioactive work.

[0038] Embodiments of another aspect of the present application provide a reactor, which comprises a reactor-based cold neutron source, and the reactor-based cold neutron source is the reactor-based cold neutron source provided in any of the foregoing embodiments.

[0039] The above embodiments are intended to further illustrate the present application in conjunction with the accompanying drawings, so that those skilled in the art can understand the technical concept of the present application. Within the scope of the present application, optimization or equivalent replacement of the technical features involved, and combination of the implementation manners in different embodiments without structural and principle conflicts, all fall within the protection scope of the present application.

Claims

1. A split in-core cold neutron source disposed in a reactor, characterized in that, comprising: a vacuum cylinder, a coolant circulation assembly and a cold blanket assembly; wherein: the vacuum cylinder comprises an inner wall and an outer wall, the inner wall and the outer wall defining a vacuum cavity in a ring shape in cross section; the coolant circulation assembly comprises a coolant input pipe and a coolant output pipe, the coolant input pipe and the coolant output pipe being connected to a coolant cavity defined by the inner wall of the vacuum cylinder, coolant flowing into the coolant cavity from the coolant input pipe and flowing out of the coolant cavity from the coolant output pipe; the cold blanket assembly is disposed in the coolant cavity and configured as a single-walled structure to allow the coolant to cool the cold blanket assembly; the cold blanket assembly contains a moderator, the cold blanket assembly comprising a cold blanket, a heat exchanger and a moderator input pipe, a siphon circulation loop being formed between the cold blanket and the heat exchanger, the moderator input pipe being used to input the moderator; the split in-core cold neutron source further comprises a sealing flange, the sealing flange being disposed at an end of the vacuum cylinder to close the coolant cavity, the sealing flange being provided with a through hole to allow the coolant input pipe, the coolant output pipe and the moderator input pipe to pass through.

2. The split-pile cold neutron source of claim 1, wherein, the vacuum cylinder further comprises a vacuum pipe interface, the vacuum pipe interface being connected to the vacuum cavity, the vacuum pipe interface being disposed on a side wall of the vacuum cylinder, the vacuum pipe not passing through the sealing flange.

3. The split-pile cold neutron source of claim 1 or 2, wherein, the cold blanket assembly further comprises an uplink pipe and a downlink pipe, the uplink pipe being connected from a top of the cold blanket to a top of the heat exchanger, the downlink pipe being connected from a bottom of the heat exchanger to a bottom of the cold blanket.

4. The split-pile cold neutron source of claim 3, wherein, the cold blanket, the uplink pipe and the downlink pipe are made of aluminum alloy and connected by welding.

5. The split-pile cold neutron source of any one of claims 1 or 2, wherein, the vacuum cylinder comprises a tube body and a head, the tube body being configured as a cylinder, the head being configured as a hemisphere.

6. The split-pile cold neutron source of any one of claims 1 or 2, wherein, in the coolant cavity, a port of the coolant input pipe is disposed above a port of the coolant output pipe.

7. The split-pile cold neutron source of any one of claims 1 or 2, wherein, the coolant is helium, and the moderator in the cold blanket assembly is liquid hydrogen or hydrogen isotope.

8. A reactor characterized by, the reactor comprises an in-core cold neutron source, the in-core cold neutron source being configured as the split in-core cold neutron source according to any one of claims 1 to 7.

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