Heavy water moderated molten salt reactor

Abstract

The present application provides a heavy water moderated molten salt reactor, which relates to the technical field of nuclear reactors. The heavy water moderated molten salt reactor provided by the present application includes a reactor vessel and a reactor core. The reactor vessel has a molten salt inlet and a molten salt outlet, and both the molten salt inlet and the molten salt outlet are located at the lower part of the reactor vessel; the reactor core is located in the reactor vessel, and the reactor core includes a molten salt channel and a heavy water accommodation space. The heavy water accommodation space wraps the molten salt channel and is filled with heavy water, and the molten salt channel is connected between the molten salt inlet and the molten salt outlet. The present application uses liquid heavy water to replace solid graphite as a moderator, which can, on the one hand, meet the moderation requirements of the molten salt reactor, and on the other hand, can also solve the problems of irradiation swelling and regular replacement of solid moderation materials, and improve the inherent safety of nuclear power plants.

Description

Technical Field

[0001] This application relates to the technical field of nuclear reactors, and particularly to a heavy water moderated molten salt reactor. Background Art

[0002] Nuclear power is an important part of clean energy. Most current nuclear reactors use uranium. However, the cost of natural uranium is rising continuously, and there are risks in the supply guarantee and cost control of uranium resources. Thorium-based molten salt reactors are reactor types that can achieve efficient utilization of thorium fuel. Developing thorium-based molten salt reactors can effectively improve the ability to ensure the supply of nuclear fuel and control costs, and guarantee energy security.

[0003] Molten salt reactors usually use liquid fuel, directly dissolving nuclear fuel in molten salt. The fuel molten salt circulates in the reactor core and the primary loop pipelines, serving as both fuel and coolant. Molten salt reactors generally use graphite moderation, which can effectively utilize thorium-based fuel. Through optimization of the reactor core layout, breeding utilization of nuclear fuel under a thermal spectrum can be achieved.

[0004] Nuclear safety is a prerequisite for the development of nuclear energy. After the Fukushima accident in Japan, the importance of passive safety systems has become increasingly prominent. The concept of passive safety means using natural forces such as gravity, natural convection, and diffusion to ensure the safety of nuclear power plants under normal and accident conditions without the intervention of an external power source, achieving the purposes of simplifying the system, reducing the probability of accidents caused by equipment failures and human errors, etc., and improving the safety of nuclear power plants. The primary loop of the thorium-based molten salt reactor is at atmospheric pressure and has certain inherent safety. Summary of the Invention

[0005] In view of this, this application provides a heavy water moderated molten salt reactor to improve the inherent safety of nuclear power plants.

[0006] In a first aspect, this application provides a heavy water moderated molten salt reactor, including:

[0007] A reactor vessel having a molten salt inlet and a molten salt outlet, both the molten salt inlet and the molten salt outlet being located at the lower part of the reactor vessel;

[0008] A reactor core located within the reactor vessel, the reactor core including a molten salt channel and a heavy water accommodation space, the heavy water accommodation space wrapping the molten salt channel and filled with heavy water, and the molten salt channel being connected between the molten salt inlet and the molten salt outlet.

[0009] In a possible implementation, the molten salt channel includes a first molten salt channel and a second molten salt channel. The first molten salt channel has a first end and a second end, the second molten salt channel has a third end and a fourth end. The first end is in communication with the molten salt inlet, the second end is in communication with the fourth end, and the third end is in communication with the molten salt outlet;

[0010] The first molten salt channel is used to guide the primary circuit molten salt to flow upward through the core, and the second molten salt channel is used to guide the primary circuit molten salt to flow downward through the core.

[0011] In a possible implementation, the core includes a first fuel pipe and a second fuel pipe, and the second fuel pipe is sleeved outside the first fuel pipe;

[0012] The internal space of the first fuel pipe forms the first molten salt channel, and the space between the first fuel pipe and the second fuel pipe forms the second molten salt channel; or the internal space of the first fuel pipe forms the second molten salt channel, and the space between the first fuel pipe and the second fuel pipe forms the first molten salt channel.

[0013] In a possible implementation, the core includes a first fuel pipe and a second fuel pipe, and one end of the first fuel pipe is communicated with one end of the second fuel pipe;

[0014] The internal space of the first fuel pipe forms the first molten salt channel, and the internal space of the second fuel pipe forms the second molten salt channel; or the internal space of the first fuel pipe forms the second molten salt channel, and the internal space of the second fuel pipe forms the first molten salt channel.

[0015] In a possible implementation, the heavy water moderated molten salt reactor further includes:

[0016] A molten salt discharge system, which includes a molten salt discharge pipe, a molten salt discharge valve and a molten salt storage tank. The molten salt discharge valve is arranged on the molten salt discharge pipe. The molten salt discharge pipe has a molten salt discharge inlet and a molten salt discharge outlet. The molten salt discharge inlet is connected to the molten salt inlet and the molten salt outlet, and the molten salt discharge outlet is connected to the molten salt storage tank.

[0017] In a possible implementation, the core includes a plurality of molten salt channels with different diameters, and the center distance between adjacent molten salt channels is the same.

[0018] In a possible implementation, the core further includes control rods, and the control rods are arranged in the heavy water between the molten salt channels.

[0019] In a possible implementation, it further includes:

[0020] A heavy water reflector, which is located inside the reactor vessel and wraps around the periphery of the core.

[0021] In one possible implementation, the reactor vessel has a heavy water inlet and a heavy water outlet, and the heavy water outlet is located at the lower part of the reactor vessel; the heavy water moderated molten salt reactor further includes:

[0022] A heavy water circulation and discharge system, which includes a heavy water circulation pipeline, a heavy water circulation pump, a first heat exchanger, a heavy water discharge pipeline, a heavy water discharge valve, and a heavy water storage tank. The heavy water circulation pipeline is connected between the heavy water inlet and the heavy water outlet; one end of the heavy water discharge pipeline is connected to the heavy water outlet, and the other end is connected to the heavy water storage tank; the heavy water circulation pump and the first heat exchanger are arranged on the heavy water circulation pipeline, and the heavy water discharge valve is arranged on the heavy water discharge pipeline.

[0023] In one possible implementation, it further includes:

[0024] A molten salt circulation pipeline, which is connected between the molten salt inlet and the molten salt outlet;

[0025] A main heat exchanger, which is located on the molten salt circulation pipeline;

[0026] A primary loop main pump, which is located on the molten salt circulation pipeline;

[0027] A secondary side residual heat removal system, which includes an electric valve, a pneumatic valve, and a second heat exchanger. The inlet pipeline of the secondary side residual heat removal system is connected to the secondary side outlet of the main heat exchanger, and the electric valve and the pneumatic valve are located between the secondary side outlet and the second heat exchanger.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] The heavy water moderated molten salt reactor provided by the present application includes a reactor vessel and a reactor core. The reactor vessel has a molten salt inlet and a molten salt outlet, and both the molten salt inlet and the molten salt outlet are located at the lower part of the reactor vessel; the reactor core is located inside the reactor vessel, and the reactor core includes a molten salt channel and heavy water, and the heavy water wraps the molten salt channel, and the molten salt channel is connected between the molten salt inlet and the molten salt outlet. The present application uses liquid heavy water to replace solid graphite as the moderator. On the one hand, it meets the moderation requirements of the molten salt reactor, and on the other hand, it can also solve the problems of irradiation swelling and regular replacement of solid moderation materials, improving the inherent safety of nuclear power plants. In addition, both the inlet and outlet of the primary loop molten salt are located at the lower part of the reactor vessel, saving the upper space of the reactor vessel and facilitating the arrangement of other equipment such as control rod drive mechanisms above the reactor core. Description of the Drawings

[0030] The accompanying drawings are provided to offer a further understanding of the present application. They are incorporated into and form a part of this application. The drawings illustrate embodiments of the present application and, together with this specification, serve to explain the principles of the present application. In the drawings:

[0031] Figure 1 is a schematic structural diagram of a heavy water moderated molten salt reactor provided by an embodiment of the present application;

[0032] Figure 2 is a schematic structural diagram of a molten salt discharge system provided by an embodiment of the present application;

[0033] Figure 3 is a schematic structural diagram of a molten salt channel provided by an embodiment of the present application;

[0034] Figure 4 is a schematic structural diagram of another molten salt channel provided by an embodiment of the present application;

[0035] Figure 5 is a schematic radial structure diagram of a reactor core provided by an embodiment of the present application;

[0036] Figure 6 is a schematic structural diagram of a heavy water circulation and sequencing system provided by an embodiment of the present application;

[0037] Figure 7 is a schematic structural diagram of a secondary side residual heat removal system provided by an embodiment of the present application.

[0038] In the figure: 100, heavy water moderated molten salt reactor; 101, primary loop system; 102, secondary loop system; 103, tertiary loop system; 111, reactor vessel; 1111, molten salt inlet; 1112, molten salt outlet; 1113, heavy water inlet; 1114, heavy water outlet; 112, reactor core; 1121, molten salt channel; 1122, heavy water containment cavity; 1123, control rod; 1124, inner space; 1125, outer space; 1211, first molten salt channel; 1212, second molten salt channel; 113, molten salt circulation pipeline; 114, main heat exchanger; 115, primary loop main pump; 116, heavy water reflector; 110, molten salt discharge system; 120, heavy water circulation and discharge system; 130, secondary side residual heat removal system; 121, steam generator; 122, secondary loop circulation pump; 1101, molten salt discharge pipeline; 1102, molten salt discharge valve; 1103, molten salt storage tank; 201, first fuel pipeline; 202, second fuel pipeline; 2011, first end; 2012, second end; 2021, third end; 2022, fourth end; 1201, heavy water circulation pipeline; 1202, heavy water circulation pump; 1203, first heat exchanger; 1204, heavy water discharge pipeline; 1205, heavy water discharge valve; 1206, heavy water storage tank; 1301, electric valve; 1302, pneumatic valve; 1303, second heat exchanger. Detailed implementation manners

[0039] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the figures represent the same structure or operation.

[0040] As shown in the present application, unless the context clearly indicates an exceptional situation, words such as "one", "a", "an", and / or "the" do not specifically refer to the singular, but may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0041] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the specification. In all the examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

[0042] In the description of the present application, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom", etc. are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Without contrary description, these orientation words do not indicate and imply that the devices or elements referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus should not be construed as limiting the protection scope of the present application; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0043] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above" can be used herein to describe the spatial positional relationship between a device or feature shown in the drawings and other devices or features. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the drawings of the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used herein.

[0044] In addition, it should be noted that the use of terms such as "first" and "second" to limit an object is only for the convenience of distinguishing the corresponding object. Without additional declaration, the above terms have no special meaning, so it should not be construed as a limitation on the protection scope of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant according to his or her judgment, and their detailed meanings are described in the relevant parts of this description. In addition, it is required to understand this application not only through the actual terms used, but also through the meaning implied by each term.

[0045] It should be understood that when a component is referred to as "on another component", "connected to another component", "coupled to another component" or "in contact with another component", it can be directly on, connected to or coupled to, or in contact with that other component, or there may be an intervening component. In contrast, when a component is referred to as "directly on another component", "directly connected to", "directly coupled to" or "directly in contact with" another component, there is no intervening component. Similarly, when a first component is referred to as "electrically contacting" or "electrically coupled to" a second component, there is an electrical path allowing current to flow between the first component and the second component. The electrical path may include capacitors, coupled inductors and / or other components allowing current to flow, even if there is no direct contact between the conductive components.

[0046] Existing molten salt reactors usually use graphite as a moderator. In a graphite-moderated molten salt reactor with liquid fuel, nuclear-grade graphite is in direct contact with the fuel molten salt and needs to meet requirements such as high purity, high density, low porosity, high strength, and high irradiation stability. At the same time, as the irradiation dose accumulates, graphite will exhibit irradiation swelling and cracking phenomena, which will damage the structural stability. Therefore, the graphite components in the reactor core need to be replaced regularly during the life cycle of the molten salt reactor. Since the primary loop system of the molten salt reactor contains a large amount of highly radioactive substances, the graphite replacement project poses a great challenge.

[0047] The embodiment of this application uses liquid heavy water to replace solid graphite as a moderator. On the one hand, it meets the moderation requirements of the molten salt reactor, and on the other hand, it can also solve the problems of irradiation swelling and regular replacement of solid moderation materials, improving the inherent safety of nuclear power plants.

[0048] Figure 1 It is a schematic structural diagram of a heavy water-moderated molten salt reactor provided by an embodiment of this application. As Figure 1As shown in the figure, the heavy water moderated molten salt reactor 100 includes a primary loop system 101, a secondary loop system 102, and a tertiary loop system 103. The primary loop system 101 is used to generate heat. The secondary loop system 102 is used to transfer the heat generated by the primary loop system 101 to the tertiary loop system 103. The tertiary loop system 103 can carry out nuclear energy comprehensive utilization such as power generation, heat supply, steam supply, device power supply, and seawater desalination.

[0049] The primary loop system 101 includes a reactor vessel 111, a reactor core 112, a molten salt circulation pipeline 113, a primary heat exchanger 114, and a primary loop main pump 115. The primary heat exchanger 114 and the primary loop main pump 115 are both located on the molten salt circulation pipeline 113. The reactor vessel 111, the primary heat exchanger 114, and the primary loop main pump 115 are connected by the molten salt circulation pipeline 113. In a specific embodiment, the primary loop system 101 relies on the primary loop main pump 115 to provide forced circulation driving force. The liquid molten salt in the primary loop system 101 is both fuel and coolant, operating at atmospheric pressure. The molten salt flows through the reactor core 112 via the molten salt channel to generate heat, and the heat is carried out of the reactor core 112, enters the primary heat exchanger 114 through the molten salt circulation pipeline 113, transfers the heat to the secondary loop molten salt, and then the primary loop molten salt enters the reactor core 112 through the primary loop main pump 115. The secondary loop system 102 includes a steam generator 121 and a secondary loop circulation pump 122. The secondary loop system 102 relies on the secondary loop circulation pump 122 to provide forced circulation driving force. The secondary loop molten salt does not contain fuel and operates at atmospheric pressure. The secondary loop molten salt is heated in the primary heat exchanger 114 and then flows into the steam generator 121, transfers the heat to the tertiary loop working medium, and then returns to the inlet of the primary heat exchanger 114 through the secondary loop circulation pump 122.

[0050] It can be understood that the heavy water moderated molten salt reactor 100 is not limited to the structure of this embodiment, but can have different variations. For example, some components can be changed or omitted, or additional components can be added.

[0051] Please refer to Figure 1 - Figure 2 , the reactor core 112 is located inside the reactor vessel 111. The reactor core 112 includes a molten salt channel 1121 and a heavy water containment cavity 1122. The heavy water containment cavity 1122 is filled with heavy water and wraps the molten salt channel 1121. The molten salt channel 1121 is used to provide a channel for the flow of the primary loop molten salt. In some embodiments, the reactor vessel 111 has a molten salt inlet 1111 and a molten salt outlet 1112. The molten salt channel 1121 is connected between the molten salt inlet 1111 and the molten salt outlet 1112. Both the molten salt inlet 1111 and the molten salt outlet 1112 are located at the lower part of the reactor vessel 111. The molten salt circulation pipeline 113 is connected between the molten salt inlet 1111 and the molten salt outlet 1112.

[0052] In an exemplary embodiment, please refer to Figure 2 - Figure 5, the molten salt channel 1121 includes a first molten salt channel 1211 and a second molten salt channel 1212. The first molten salt channel 1211 has a first end 2011 and a second end 2012, and the second molten salt channel 1212 has a third end 2021 and a fourth end 2022. The first end 2011 is communicated with the molten salt inlet 1111, the second end 2012 is communicated with the fourth end 2022, and the third end 2021 is communicated with the molten salt outlet 1112. The first molten salt channel 1211 is used to guide the primary circuit molten salt to flow upward through the core 112, and the second molten salt channel 1212 is used to guide the primary circuit molten salt to flow downward through the core 112.

[0053] Exemplarily, the primary circuit molten salt enters the reactor vessel 111 from the molten salt inlet 1111, flows upward through the core 112 via the first molten salt channel 1211, turns after reaching the top of the core 112, and then flows downward through the core 112 again via the second molten salt channel 1212. After the primary circuit molten salt reaches the lower end of the second molten salt channel 1212, it flows out of the reactor vessel 111 via the molten salt outlet 1112. The primary circuit molten salt undergoes a fission reaction to generate heat during the process of flowing through the first molten salt channel 1211 and the second molten salt channel 1212, and takes out the heat from the core 112 through the flow.

[0054] In the embodiment of the present application, both the inlet and the outlet of the primary circuit molten salt are located at the lower part of the reactor vessel 111, which saves the upper space of the reactor vessel 111 and is beneficial to arranging other devices such as control rod drive mechanisms at the upper part of the core 112. For example, refer to Figure 2 As shown, the core 112 further includes a control rod 1123, and a part of the control rod 1123 is arranged in the heavy water containing cavity 1122 between the molten salt channels 1121. The control rod 1123 can be inserted or lifted in the heavy water containing cavity 1122, and the reactivity of the core 112 is controlled by inserting or lifting. In case of an accident, the control rod drive mechanism is powered off, and the control rod 1123 can be inserted into the core 112 by gravity to make the molten salt reactor passively shut down. Arranging the control rod 1123 in the heavy water containing cavity between the molten salt channels does not affect the fuel arrangement in the reactor and improves the reactivity control ability.

[0055] In some embodiments, the core 112 includes a first fuel pipe 201 and a second fuel pipe 202 to form the first molten salt channel 1211 and the second molten salt channel 1212. Please refer to Figure 3, in one embodiment, the second fuel pipe 202 is sleeved outside the first fuel pipe 201. The internal space of the first fuel pipe 201 forms a first molten salt channel 1211, and the space between the first fuel pipe 201 and the second fuel pipe 202 forms a second molten salt channel 1212. It can be understood that in some other embodiments, the internal space of the first fuel pipe 201 may also form a second molten salt channel 1212, and the space between the first fuel pipe 201 and the second fuel pipe 202 forms a first molten salt channel 1211.

[0056] Please refer to Figure 4 , in another embodiment, the first fuel pipe 201 and the second fuel pipe 202 are arranged side by side, and one end of the first fuel pipe 201 is communicated with one end of the second fuel pipe 202. The internal space of the first fuel pipe 201 forms a first molten salt channel 1211, and the internal space of the second fuel pipe 202 forms a second molten salt channel 1212. It can be understood that in some other embodiments, the internal space of the first fuel pipe 201 may also form a second molten salt channel 1212, and the internal space of the second fuel pipe 202 forms a first molten salt channel 1211.

[0057] Continue to refer to Figure 1 , the heavy water moderated molten salt reactor 100 further includes a molten salt discharge system 110. The molten salt discharge system 110 is connected to the lower part of the reactor vessel 111. Under some severe accident conditions, the molten salt discharge system 110 is activated, and the primary loop molten salt in the reactor core 112 is discharged by gravity, the molten salt reactor is safely shut down, and the waste heat in the primary loop molten salt is removed.

[0058] In some embodiments, please refer to Figure 2 , the molten salt discharge system 110 includes a molten salt discharge pipe 1101, a molten salt discharge valve 1102 and a molten salt storage tank 1103. The molten salt discharge valve 1102 is arranged on the molten salt discharge pipe 1101. The molten salt discharge pipe 1101 has a molten salt discharge inlet and a molten salt discharge outlet, wherein the molten salt discharge inlet is connected to the molten salt inlet 1111 and the molten salt outlet 1112, and the molten salt discharge outlet is connected to the molten salt storage tank 1103. In this embodiment, both the molten salt inlet 1111 and the molten salt outlet 1112 are located at the lower part of the reactor vessel 111. The molten salt discharge inlet is simultaneously connected to the molten salt inlet 1111 and the molten salt outlet 1112. Under accident conditions, both the molten salt inlet 1111 and the molten salt outlet 1112 can be used for discharging molten salt, which is beneficial to molten salt discharge and improves safety.

[0059] Exemplarily, the molten salt discharge system 110 includes two molten salt discharge valves 1102, which are respectively disposed between the molten salt inlet 1111 and the molten salt storage tank 1103, and between the molten salt outlet 1112 and the molten salt storage tank 1103. Specifically, a molten salt discharge pipeline 1101 is connected in parallel to each of the molten salt inlet 1111 and the molten salt outlet 1112 to connect to the molten salt discharge valve 1102, and then connected to the molten salt storage tank 1103. In some embodiments, the molten salt discharge valve 1102 is a freeze valve. During normal operation, the molten salt discharge valve 1102 is in a normally closed state. Under accident conditions, when the temperature of the molten salt rises, the molten salt discharge valve 1102 is triggered to open due to the high temperature. The primary circuit molten salt discharges through the parallel molten salt discharge pipelines 1101 at the molten salt inlet 1111 and the molten salt outlet 1112, and enters the molten salt storage tank 1103 via the molten salt discharge valve 1102. The molten salt in the core 112 is emptied, and the molten salt reactor is safely shut down. The residual heat in the molten salt is discharged through the residual heat discharge system of the molten salt storage tank 1103. In some other embodiments, the molten salt discharge valve 1102 is a solenoid valve. During normal operation, the molten salt discharge valve 1102 is in a normally closed state. Under accident conditions, the molten salt discharge valve 1102 loses power and opens.

[0060] In some embodiments, please refer to Figure 5 , the core 112 includes a plurality of molten salt channels 1121 with different diameters, and the center distance between adjacent molten salt channels 1121 is the same. It should be noted that as Figure 5 shown, when the first fuel pipeline 201 and the second fuel pipeline 202 are sleeved inside and outside, the sleeved first fuel pipeline 201 and second fuel pipeline 202 are regarded as a total fuel pipeline, and the center distance between adjacent two total fuel pipelines is the center distance between adjacent molten salt channels 1121. When the first fuel pipeline 201 and the second fuel pipeline 202 are arranged side by side, as Figure 4 shown, both the first fuel pipeline 201 and the second fuel pipeline 202 are a single fuel pipeline, and the center distance between adjacent two single fuel pipelines is the center distance between adjacent molten salt channels.

[0061] In a specific embodiment, the primary circuit molten salt flows upward through the core 112 via the first molten salt channel 1211 in the first fuel pipeline 201, and flows downward through the core 112 via the second molten salt channel 1212 between the first fuel pipeline 201 and the second fuel pipeline 202. The outside of the second fuel pipeline 202 is a heavy water accommodation space (such as the heavy water accommodation cavity 1122), thus forming a core grid. The core 112 is composed of a plurality of such grids arranged together, and the grids in the core 112 can be arranged in forms such as square or hexagonal. The center distance between all adjacent grids in the core 112 is the same, that is, the center distance between adjacent molten salt channels 1121 is the same.

[0062] The internal space of the core 112 includes an inner space 1124 ( Figure 5 the space within the dashed circle in Figure 5 ), and an outer space 1125 ( Figure 5 the space outside the dashed circle in Figure 5 ), and the outer space 1125 wraps the inner space 1124. In some embodiments, the diameter of the molten salt channel 1121 in the inner space 1124 of the core 112 is smaller, obtaining better moderation to increase the effective multiplication factor of the core 112; the diameter of the molten salt channel 1121 in the outer space 1125 of the core 112 is larger, with slightly worse moderation, to obtain a better fuel multiplication effect. For example, the diameter of the first molten salt channel 1211 in the inner space 1124 of the core 112 is smaller than the diameter of the first molten salt channel 1211 in the outer space 1125 of the core 112, and the diameter of the second molten salt channel 1212 in the inner space 1124 of the core 112 is smaller than the diameter of the second molten salt channel 1212 in the outer space 1125 of the core 112, and the ratio of the diameter of the first molten salt channel 1211 to the diameter of the second molten salt channel 1212 in the core 112 can remain unchanged. In some other embodiments, it is also possible that the diameter of the molten salt channel 1121 in the inner space 1124 of the core 112 is larger, the diameter of the molten salt channel 1121 in the outer space 1125 of the core 112 is smaller, or the larger-diameter molten salt channels 1121 and the smaller-diameter molten salt channels 1121 are arranged alternately from the inside out, or the diameter of the molten salt channels 1121 increases or decreases sequentially from the inside out, to adjust the fuel moderator ratio, achieve the purpose of flattening the power distribution, changing the multiplication ratio, etc. For example, the diameter of the first molten salt channel 1211 in the inner space 1124 of the core 112 is larger than the diameter of the first molten salt channel 1211 in the outer space 1125 of the core 112, and the diameter of the second molten salt channel 1212 in the inner space 1124 of the core 112 is larger than the diameter of the second molten salt channel 1212 in the outer space 1125 of the core 112. It can be understood that the division of the inner space 1124 and the outer space 1125 of the core 112 is not limited to Figure 5 the embodiments shown, Figure 5 and the embodiments shown are only for illustrative purposes.

[0063] The heavy water moderated molten salt reactor 100 further includes a heavy water reflector 116 located within the reactor vessel 111. The heavy water reflector 116 wraps around the periphery of the core 112 to reduce leakage and improve neutron economy.

[0064] Continue to refer to Figure 1, the reactor vessel 111 has a heavy water inlet 1113 and a heavy water outlet 1114, and the heavy water outlet 1114 is located at the lower part of the reactor vessel 111. The heavy water moderated molten salt reactor 100 further includes a heavy water circulation and discharge system 120 connected between the heavy water inlet 1113 and the heavy water outlet 1114. The heavy water can better discharge heat through circulation, and the heavy water can also maintain a high purity through circulation purification. Under some accident conditions that require rapid reactor shutdown, the heavy water circulation and discharge system 120 is started, and the heavy water in the reactor vessel 111 is emptied by gravity, and the molten salt reactor is safely shut down.

[0065] In some embodiments, please refer to Figure 6 , the heavy water circulation and discharge system 120 includes a heavy water circulation pipeline 1201, a heavy water circulation pump 1202, a first heat exchanger 1203, a heavy water discharge pipeline 1204, a heavy water discharge valve 1205 and a heavy water storage tank 1206. The heavy water circulation pipeline 1201 is connected between the heavy water inlet 1113 and the heavy water outlet 1114. One end of the heavy water discharge pipeline 1204 is connected to the heavy water outlet 1114, and the other end is connected to the heavy water storage tank 1206. The heavy water circulation pump 1202 and the first heat exchanger 1203 are arranged on the heavy water circulation pipeline 1201, and the heavy water discharge valve 1205 is arranged on the heavy water discharge pipeline 1204.

[0066] Specifically, the heavy water in the reactor vessel 111 provides a neutron moderation function for the core 112 and generates a part of heat at the same time. The heavy water circulation and discharge system 120 relies on the heavy water circulation pump 1202 to provide a forced circulation driving force. The heavy water flows out from the heavy water outlet 1114 at the bottom of the reactor vessel 111, flows into the first heat exchanger 1203 through the heavy water circulation pump 1202, discharges the excess heat in the heavy water, and the cooled heavy water returns to the reactor vessel 111 through the top of the core 112. A heavy water discharge pipeline 1204 is connected in parallel to the heavy water outlet 1114 at the lower part of the reactor vessel 111 to connect the heavy water discharge valve 1205. During normal operation, the heavy water discharge valve 1205 is in a normally closed state. Under accident conditions, the heavy water discharge valve 1205 is opened, and the heavy water in the reactor vessel 111 is discharged through the heavy water discharge pipeline 1204 connected to the heavy water outlet 1114 and enters the heavy water storage tank 1206 through the heavy water discharge valve 1205. The heavy water in the reactor vessel 111 is emptied without external power, the core 112 loses moderation, and the molten salt reactor is safely shut down.

[0067] Continue to refer to Figure 1 , the heavy water moderated molten salt reactor 100 further includes a secondary side residual heat removal system 130. The secondary side residual heat removal system 130 is connected in parallel to the main heat exchanger 114. Under some accident conditions, the secondary side residual heat removal system 130 is started to discharge the residual heat of the core through natural circulation.

[0068] In some embodiments, please refer toFigure 7 , the secondary side residual heat removal system 130 includes an electric valve 1301, a pneumatic valve 1302, and a second heat exchanger 1303. The inlet pipe of the secondary side residual heat removal system 130 is connected to the secondary side outlet of the main heat exchanger 114. The electric valve 1301 and the pneumatic valve 1302 are located between the secondary side outlet and the second heat exchanger 1303. The secondary side residual heat removal system 130 may include one or more parallel pneumatic valves 1302 to improve safety. Exemplarily, the secondary side residual heat removal system 130 includes a normally open electric valve 1301 and two parallel normally closed pneumatic valves 1302. The pneumatic valves 1302 open when de-energized, and the secondary side residual heat removal system 130 starts, relying on natural circulation to take away the residual heat in the reactor core 112. This design of passive residual heat removal greatly improves the safety of the molten salt reactor.

[0069] Specifically, during normal operation, the electric valve 1301 is in the normally open state, and the pneumatic valve 1302 is in the normally closed state. During maintenance, the electric valve 1301 is manually closed to prevent misoperation of the system. Under accident conditions, the pneumatic valve 1302 opens, and the residual heat of the reactor core is transferred to the molten salt in the secondary loop through natural circulation in the primary loop via the main heat exchanger 114. The secondary side residual heat removal system 130 transfers heat to the second heat exchanger 1303 through natural circulation. The second heat exchanger 1303 is immersed in a water tank, and heat is removed by evaporation of water, enabling long-term unattended operation after an accident. The secondary side residual heat removal system 130 belongs to a dedicated safety facility, which is a safety-related system that can remove the residual heat of the reactor core and achieve in-depth defense under the condition that the normal residual heat removal function fails and the loop can operate normally.

[0070] In the above embodiments, the secondary side residual heat removal system 130 adopts a water-cooling method, and the ultimate heat sink is a water tank. In some other embodiments, the secondary side residual heat removal system 130 may also adopt other cooling methods, such as air-cooling, and the ultimate heat sink is the atmosphere. The molten salt working fluid in the system directly discharges heat into the atmosphere through an air-cooling tower. By virtue of the natural temperature difference between the molten salt and the air, a passive circulation loop is designed, and the mechanisms of natural convection and natural circulation are utilized. Through the optimized configuration of the pipe diameter, routing, and heat exchanger position of the molten salt loop, it is ensured that the molten salt can flow spontaneously, continuously, and stably without external power, forming an efficient heat transfer path, greatly improving the residual heat removal efficiency, and reducing the risk of mechanical failure.

[0071] The embodiments of the present application fully implement the concept of passive safety, and further propose safety systems such as the molten salt discharge system 110, the heavy water circulation and discharge system 120, and the secondary side residual heat removal system 130, which achieve reactivity control and core residual heat removal after a molten salt reactor accident in a passive form, improving the safety of the heavy water moderated molten salt reactor.

[0072] The heavy water moderated molten salt reactor of the embodiment of the present application includes three sets of reactivity control systems. The first set is the control rod system, which controls the insertion or extraction of neutron absorbers into or from the reactor core through the control rod drive mechanism to achieve the purpose of reactivity control. In case of an accident, the control rods rely on the energy storage device to quickly insert into the reactor core to passively shut down the molten salt reactor. The second set is the heavy water circulation and discharge system, which changes the neutron moderation ability of the reactor core by changing the level of heavy water in the reactor vessel to achieve the purpose of reactivity control. In case of an accident, the heavy water discharge valve loses power and opens to passively shut down the molten salt reactor. The third set is the molten salt discharge system, which achieves the purpose of reactivity control by discharging the fuel molten salt (i.e., the primary circuit molten salt) from the reactor core. In case of an accident, the molten salt is quickly discharged into the molten salt storage tank through the molten salt discharge valve to passively shut down the molten salt reactor. All three systems adopt passive designs and have different working principles, avoiding common cause failures and improving the safety of the molten salt reactor.

[0073] The basic concepts have been described above. Obviously, for those skilled in the art, the above invention disclosure is only an example and does not constitute a limitation to the present application. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to the present application. Such modifications, improvements, and corrections are proposed in the present application, so such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of the present application.

[0074] At the same time, the present application uses specific terms to describe the embodiments of the present application. Such as "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the present application can be appropriately combined.

[0075] Similarly, it should be noted that in order to simplify the description of the present application disclosure and thus help the understanding of one or more inventive embodiments, in the previous description of the embodiments of the present application, sometimes multiple features are merged into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the features required by the object of the present application are more than the features mentioned. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0076] Although the present application has been described with reference to the current specific embodiments, those of ordinary skill in the art in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions can be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications of the above embodiments are within the scope of the substantial spirit of the present application, they will fall within the scope of the present application.

Claims

1. A heavy water moderated molten salt reactor, characterized in that: include: A reactor vessel having a molten salt inlet and a molten salt outlet, wherein the molten salt inlet and the molten salt outlet are both located at a lower portion of the reactor vessel; A core located in the reactor vessel, the core comprising a molten salt channel and a heavy water containing space, the heavy water containing space wraps the molten salt channel and is filled with heavy water, the molten salt channel is connected between the molten salt inlet and the molten salt outlet; A molten salt discharge system, the molten salt discharge system comprising a molten salt discharge pipeline, a molten salt discharge valve and a molten salt storage tank, the molten salt discharge valve being arranged on the molten salt discharge pipeline, the molten salt discharge pipeline having a molten salt discharge inlet and a molten salt discharge outlet, wherein the molten salt discharge inlet is connected to the molten salt inlet and the molten salt outlet, and the molten salt discharge outlet is connected to the molten salt storage tank.

2. The heavy water moderated molten salt reactor according to claim 1, characterized in that: The molten salt channel comprises a first molten salt channel and a second molten salt channel, the first molten salt channel has a first end and a second end, the second molten salt channel has a third end and a fourth end, the first end is communicated with the molten salt inlet, the second end is communicated with the fourth end, and the third end is communicated with the molten salt outlet; The first molten salt channel is used to guide the primary molten salt to flow through the core from bottom to top, and the second molten salt channel is used to guide the primary molten salt to flow through the core from top to bottom.

3. The heavy water moderated molten salt reactor according to claim 2, characterized in that: The core comprises a first fuel pipeline and a second fuel pipeline, wherein the second fuel pipeline is sleeved outside the first fuel pipeline; The inner space of the first fuel pipeline is formed as the first molten salt channel, and the space between the first fuel pipeline and the second fuel pipeline is formed as the second molten salt channel; or the inner space of the first fuel pipeline is formed as the second molten salt channel, and the space between the first fuel pipeline and the second fuel pipeline is formed as the first molten salt channel.

4. The heavy water moderated molten salt reactor according to claim 2, characterized in that: The core includes a first fuel pipeline and a second fuel pipeline, one end of the first fuel pipeline is connected to one end of the second fuel pipeline; The inner space of the first fuel pipeline is formed as the first molten salt channel, and the inner space of the second fuel pipeline is formed as the second molten salt channel; or the inner space of the first fuel pipeline is formed as the second molten salt channel, and the inner space of the second fuel pipeline is formed as the first molten salt channel.

5. The heavy water moderated molten salt reactor according to claim 1, characterized in that: The core includes a plurality of molten salt channels with different diameters, and the center distances between adjacent molten salt channels are the same.

6. The heavy water moderated molten salt reactor according to claim 1, characterized in that: The core also includes control rods disposed in the heavy water between the molten salt channels.

7. The heavy water moderated molten salt reactor according to claim 1, characterized in that: Also includes: A heavy water reflecting layer is located in the reactor vessel, and the heavy water reflecting layer wraps around the periphery of the core.

8. The heavy water moderated molten salt reactor according to any one of claims 1 to 7, characterized in that: The reactor vessel has a heavy water inlet and a heavy water outlet, and the heavy water outlet is located at the lower part of the reactor vessel; the heavy water moderated molten salt reactor also includes: A heavy water circulation and discharge system, comprising a heavy water circulation pipeline, a heavy water circulation pump, a first heat exchanger, a heavy water discharge pipeline, a heavy water discharge valve, and a heavy water storage tank, wherein the heavy water circulation pipeline is connected between the heavy water inlet and the heavy water outlet; one end of the heavy water discharge pipeline is connected to the heavy water outlet, and the other end is connected to the heavy water storage tank; the heavy water circulation pump and the first heat exchanger are arranged on the heavy water circulation pipeline, and the heavy water discharge valve is arranged on the heavy water discharge pipeline.

9. The heavy water moderated molten salt reactor according to any one of claims 1 to 7, characterized in that: Also includes: A molten salt circulation pipeline connected between the molten salt inlet and the molten salt outlet; A main heat exchanger, located on the molten salt circulation pipeline; A primary circuit main pump is located on the molten salt circulation pipeline; The secondary side waste heat removal system comprises an electric valve, a pneumatic valve and a second heat exchanger. The inlet pipe of the secondary side waste heat removal system is connected to the secondary side outlet of the main heat exchanger. The electric valve and the pneumatic valve are located between the secondary side outlet and the second heat exchanger.

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