1. A dual mode spatial nuclear reactor core, comprising: the fuel block comprises a heat pipe (1) and a hydrogen flow channel (9), wherein hydrogen can be heated by the fuel block through the hydrogen flow channel (9) and then is sprayed out as power, and meanwhile, the hydrogen can also have a cooling effect on the fuel block.

2. A dual mode spatial nuclear reactor core as claimed in claim 1, wherein:

the fuel block is a cylindrical fuel block formed by an inner ring fuel (5) and an outer ring fuel (4) together, and the outer ring fuel (4) surrounds the periphery of the inner ring fuel (5);

a heat pipe channel (8) is arranged on the outer ring fuel (4), a heat pipe (1) is arranged in the heat pipe channel (8), and the top end of the heat pipe (1) extends out of the top end of the outer ring fuel (4);

the outer ring fuel (4) and the inner ring fuel (5) are both provided with a plurality of blocks, each outer ring fuel (4) and each inner ring fuel (5) are provided with a plurality of hydrogen flow channels (9), and the hydrogen flow channels (9) are parallel to the axis of the fuel blocks and penetrate through the fuel blocks;

the hydrogen flow channel (9) on the outer ring fuel (4) is a second hydrogen flow channel, and the hydrogen flow channel (9) on the inner ring fuel (5) is a third hydrogen flow channel.

3. A dual mode spatial nuclear reactor core as claimed in claim 2, wherein: the top end of the second hydrogen flow channel is communicated with the top end of the third hydrogen flow channel, and when the hydrogen is ejected from the fuel block as power, the hydrogen firstly flows into the top end of the third hydrogen flow channel from the bottom end of the second hydrogen flow channel to cool the outer ring fuel (4); then flows into the third hydrogen flow channel from the top end of the third hydrogen flow channel, and is heated by the obtained inner ring fuel (5) and then is sprayed out from the bottom end of the third hydrogen flow channel.

4. A dual mode spatial nuclear reactor core as claimed in claim 3, wherein: the fuel core further comprises a radial reflecting layer (3) arranged on the periphery of the outer ring fuel (4), and the radial reflecting layer (3) is used for reflecting fission neutrons to the fuel blocks so as to reduce the neutron leakage rate of the reactor core; the fuel block is characterized by further comprising a plurality of control drums (2) arranged in the radial reflecting layer (3), the control drums (2) are cylindrical and parallel to the axis of the fuel block, the main body of each control drum (2) is a reflector, a neutron absorber (7) is arranged on part of the side surface of each control drum (2), and each neutron absorber (7) is used for absorbing neutrons of fission and diffusion in the fuel block; when the neutron absorber (7) faces the fuel block with the rotation of the control drum (2), the reactivity of the core can be reduced; when the neutron absorbers (7) on all the control drums (2) face the fuel blocks, the reactor is shut down, and otherwise, the reactor is started and power is adjusted.

5. A dual mode spatial nuclear reactor core as claimed in claim 4, wherein: further comprising a first hydrogen flow channel, which is the hydrogen flow channel (9) provided in the radial reflection layer (3) and the control drum (2), in parallel with the axis of the fuel brick; the bottom end of the first hydrogen flow channel is communicated with the bottom end of the second hydrogen flow channel, and when the hydrogen is ejected from the fuel block as power, the hydrogen firstly flows into the bottom end of the second hydrogen flow channel from the bottom end of the first hydrogen flow channel to cool the radial reflecting layer (3) and the control drum (2); and then flows into the second hydrogen flow channel from the bottom end of the second hydrogen flow channel.

6. A dual mode spatial nuclear reactor core as claimed in claim 5, wherein: the top end of the fuel block is provided with an axial reflecting layer (10), and the hydrogen flow channel (9) and the heat pipe channel (8) penetrate through the axial reflecting layer (10).

7. A dual mode spatial nuclear reactor core as claimed in claim 1, wherein: the material of the fuel block is tungsten-based CERMET fuel; the outer surface of the fuel block and the surface of the hydrogen flow channel (9) are provided with tungsten-rhenium alloy coatings.

8. A dual mode spatial nuclear reactor core as claimed in claim 1, wherein: the working medium inside the heat pipe (1) is sodium or lithium.

9. A dual mode spatial nuclear reactor core as claimed in claim 1, wherein: the cladding material of the heat pipe (1) is a refractory metal alloy, and the refractory metal alloy comprises molybdenum-rhenium alloy or tungsten-rhenium alloy.

10. A dual mode spatial nuclear reactor core as claimed in claim 2, wherein: and a safety rod channel (6) is arranged at the axis position of the fuel block and used for accommodating a safety rod, and the safety rod is used for ensuring that the reactor can maintain a subcritical safety state when a launching and dropping accident occurs.

Background

The dual-mode space nuclear reactor has both propulsion and power generation functions, and combines many advantages of a nuclear thermal propulsion reactor and a space reactor power supply relative to conventional energy sources. The reactor is very suitable for tasks such as manned lunar landing, manned Mars, space transportation and the like. The aerospace major countries such as america and russia have conducted extensive research on the dual-mode reactor, and more reactor schemes are proposed, and the dual-mode reactor can be classified into two types according to the way of leading out heat for power generation from the reactor core: firstly, a coolant loop is adopted to lead out heat for power generation; and secondly, heat for generating electricity is led out by adopting a heat pipe. Compared with a coolant loop, the heat pipe has the advantages of simplicity, passive performance, single-point failure resistance, high reliability and the like. Three solutions using heat pipes will be described below.

(1) Houts et al in the United states of America in the literature "Alert-derivative biological space power and propulsion systems" mention a dual mode reactor scheme ALERT based on a hot tube reactor. The structure of the core active area is shown in figure 5 (hydrogen flow channels in fuel are not shown in the figure), the scheme adopts annular plate-shaped uranium carbide fuel, the core active area is formed by overlapping a plurality of fuel plates, tungsten plates are arranged among the fuel plates for enhancing the heat conduction capacity, and a plurality of axial hydrogen flow channels are arranged in the fuel and tungsten plates. A plurality of heat pipes are arranged at the center hole and the periphery of the active area, the working medium of the heat pipes is sodium, the cladding material is niobium, two layers of containers are arranged between the fuel and the heat pipes, and a certain gap is reserved between the containers. The reactor operates in two modes: a propulsion mode and a power generation mode. In the propulsion mode, hydrogen flows through the fuel and the hydrogen flow channel in the tungsten plate from top to bottom, and is sprayed out after being heated, so that thrust is generated, and at the moment, the two layers of containers are in vacuum, so that the heat transfer performance between the fuel and the heat pipe is weakened, and the heat pipe is prevented from being overheated; in the power generation mode, hydrogen is stopped to be discharged, the heat of the reactor core is led out of the reactor by the heat pipe to be used for power generation, and at the moment, helium is filled between the two layers of containers to enhance the heat transfer performance between the fuel and the heat pipe.

(2) Houts et al in the United states of America in the documents "Heat power system and heat dual system maintenance" mention a dual mode reactor scheme HBS based on a heat pipe reactor. The fuel and heat pipe arrangement structure is shown in figure 6, the fuel rods and the heat pipe are arranged in a triangular grid mode, a cavity between the fuel rods and the heat pipe is used as a hydrogen flow channel, the fuel is firstly uranium dioxide, then (U, Ta) C or W- (U, Zr) CN which can resist high temperature is provided, the heat pipe is provided with double-layer cladding, an outer cladding is tungsten, an inner cladding is molybdenum, a working medium is sodium or lithium, and a vacuum gap is formed between the two layers of cladding so as to prevent the heat pipe from overheating. In the propulsion mode, hydrogen flows through a hydrogen flow channel between the fuel rod and the heat pipe from top to bottom, and is ejected out to generate thrust after being heated; and in the power generation mode, the hydrogen is stopped to be discharged, and the heat of the reactor core is led out of the reactor by the heat pipe to be used for power generation.

(3) Polansky et al, in the U.S. A bimodal spaced bus based on a rounded fused heat pipe reactor, mention a dual mode reactor scheme based on a heat pipe reactor. The structure of the heat pipe is shown in figure 7, and the arrangement structure of the heat pipe and the fuel is shown in figure 8. The fuel and the heat pipe have special structures, wherein the fuel is tungsten-based CERMET fuel, has a structure of a nine-prism shape and contains a plurality of axial hydrogen flow channels; the working medium of the heat pipe is sodium, the cladding is molybdenum, and the periphery of the heat pipe comprises 6 fins and 6 hydrogen flow channels. A vacuum gap is formed between the fuel rod and the heat pipe, and the fuel rod and the heat pipe are in heat transfer through radiation. In the propulsion mode, hydrogen flows through 3 hydrogen flow channels which are not adjacent to each other on the periphery of the heat pipe from top to bottom, flows through the other 3 hydrogen flow channels from bottom to top after reaching the bottom, then flows through the hydrogen flow channels in the fuel from top to bottom, and is finally sprayed out; and in the power generation mode, the hydrogen emission is stopped, and the heat of the reactor core is led out of the reactor by the heat pipe to be used for power generation.

The above three types of dual mode reactor schemes all suffer from disadvantages, as analyzed below:

(1) for the ALERT scheme, two layers of containers are arranged between the fuel and the heat pipe, and in the propulsion mode, gaps among the containers need to be vacuumized, so that heat transfer is reduced to protect the heat pipe; in the power generation mode, the gap is filled with helium to enhance heat transfer. Such switching increases the complexity of the system and reduces the reliability of the system.

(2) For the HBS scheme, the hydrogen flow channel is located in the gap between the fuel rods and the heat pipe. On one hand, the heat transfer efficiency between the fuel and the hydrogen is poor under the structure, and the outlet temperature of the hydrogen is not favorably improved; on the other hand, in the power generation mode, the contact area between the fuel and the heat pipe is small, the heat transfer efficiency is poor, and the heat transfer performance between the fuel and the heat pipe is further reduced by the double-layer cladding (the gap is vacuum) structure.

(3) For the third scheme, on one hand, the hydrogen flow channel is arranged more complicated, so that the complexity of the system is increased; on the other hand, in the power generation mode, the fuel and the heat pipe transfer heat by radiation, and the heat transfer efficiency is poor.

Disclosure of Invention

Aiming at the analysis of the defects of the existing technical scheme in the background technology part, the invention aims to provide a brand-new core arrangement scheme, and the core can realize the following purposes: 1) the safety of the heat pipe is improved, so that the heat pipe can safely operate at a proper temperature, and the heat pipe is prevented from being damaged due to overheating; 2) on the premise of ensuring the safety of the heat pipe, the heat transfer mode between the fuel and the heat pipe is simplified, and the heat transfer performance between the fuel and the heat pipe is enhanced; 3) the hydrogen flow channel arrangement is simplified, and the heat transfer performance between the fuel and the hydrogen is enhanced at the same time, so that the temperature of the hydrogen outlet is improved.

In order to achieve the purpose, the technical scheme adopted by the invention is that the dual-mode spatial nuclear reactor core comprises a fuel block provided with a heat pipe and a hydrogen flow channel, hydrogen can be heated by the fuel block through the hydrogen flow channel and then is sprayed out to serve as power, and meanwhile, the hydrogen can also generate a cooling effect on the fuel block.

Further, in the present invention,

the fuel block is a cylindrical fuel block formed by an inner ring fuel and an outer ring fuel together, and the outer ring fuel surrounds the inner ring fuel;

a heat pipe channel is arranged on the outer ring fuel, a heat pipe is arranged in the heat pipe channel, and the top end of the heat pipe extends out of the top end of the outer ring fuel;

the outer ring fuel and the inner ring fuel are both a plurality of blocks, each outer ring fuel and each inner ring fuel are provided with a plurality of hydrogen flow channels, and the hydrogen flow channels are parallel to the axis of the fuel block and penetrate through the fuel block;

the hydrogen flow channel on the outer ring fuel is a second hydrogen flow channel, and the hydrogen flow channel on the inner ring fuel is a third hydrogen flow channel.

Further, the top end of the second hydrogen flow channel is communicated with the top end of the third hydrogen flow channel, and when the hydrogen is ejected from the fuel block as power, the hydrogen firstly flows into the top end of the third hydrogen flow channel from the bottom end of the second hydrogen flow channel to cool the outer ring fuel; then flows into the third hydrogen flow channel from the top end of the third hydrogen flow channel, and is heated by the fuel of the inner ring and then is sprayed out from the bottom end of the third hydrogen flow channel.

The fuel block is provided with an outer ring fuel, and the outer ring fuel is provided with a radial reflecting layer which is arranged on the periphery of the outer ring fuel and used for reflecting fission neutrons to the fuel block so as to reduce the neutron leakage rate of the reactor core; the fuel block is characterized by further comprising a plurality of control drums arranged in the radial reflecting layer, the control drums are cylindrical and parallel to the axis of the fuel block, the main bodies of the control drums are reflectors, and neutron absorbers are arranged on partial side surfaces of the control drums and used for absorbing fission-diffused neutrons in the fuel block; when the neutron absorber faces the fuel block with the rotation of the control drum, the reactivity of the core can be reduced; when the neutron absorbers on all the control drums face the fuel blocks, the reactor is shut down, and otherwise, the reactor is started and power is adjusted.

Further, a first hydrogen flow channel is included, which is the hydrogen flow channel provided in the radial reflection layer and the control drum, in parallel with the axis of the fuel brick; the bottom end of the first hydrogen flow channel is communicated with the bottom end of the second hydrogen flow channel, and when the hydrogen is sprayed out from the fuel block as power, the hydrogen firstly flows into the bottom end of the second hydrogen flow channel from the bottom end of the first hydrogen flow channel to cool the radial reflecting layer and the control drum; and then flows into the second hydrogen flow channel from the bottom end of the second hydrogen flow channel.

Further, an axial reflecting layer is arranged at the top end of the fuel block, and the hydrogen flow channel and the heat pipe channel penetrate through the axial reflecting layer.

Further, the material of the fuel block is tungsten-based CERMET fuel; and the outer surface of the fuel block and the surface of the hydrogen flow channel are provided with tungsten-rhenium alloy coatings.

Further, the working medium inside the heat pipe is sodium or lithium.

Further, the cladding material of the heat pipe is a refractory metal alloy, and the refractory metal alloy comprises a molybdenum-rhenium alloy or a tungsten-rhenium alloy.

Further, a safety rod channel is arranged at the axis position of the fuel block and used for accommodating a safety rod, and the safety rod is used for ensuring that the reactor can maintain a subcritical safety state when a launching and dropping accident occurs.

The invention has the beneficial effects that:

1. in the propulsion mode, the hydrogen working medium firstly flows through the outer ring fuel 4 and then flows through the inner ring fuel 5, so that the operating temperature of the outer ring fuel 4 is far lower than that of the inner ring fuel 5, therefore, the heat pipe 1 can be operated at an appropriate temperature by arranging the heat pipe 1 on the outer ring fuel 4, and the heat pipe 1 is ensured not to be overheated. In the power generation mode, the power of the reactor core is low, and at the moment, the heat pipe 1 can also be safely operated under the appropriate temperature condition.

2. The ALERT scheme (see fig. 5) in the background art requires evacuation and helium filling of the gap between the double-layered vessel 12 and the heat pipe 1 and the fuel 11 in the propulsion and power generation modes, respectively, which complicates the operation of the reactor and reduces the reliability of the system. Compared with the prior art, the scheme provided by the invention can simplify the operation mode of the reactor and improve the reliability of the system.

3. In the HBS scheme (see fig. 6) in the background art, the heat transfer efficiency between the fuel 11 and the hydrogen working medium is poor, which is not favorable for increasing the outlet temperature of the hydrogen working medium; in the power generation mode, the contact area between the fuel 11 and the double-clad heat pipe 13 is small, the heat transfer efficiency is poor, and the double-clad (void is vacuum) structure further reduces the heat transfer performance between the fuel 11 and the double-clad heat pipe 13. Compared with the prior art, the scheme provided by the invention greatly improves the heat transfer efficiency between the fuel block and the hydrogen working medium on one hand, and also obviously improves the heat transfer performance between the fuel block and the heat pipe 1 on the other hand.

4. In the third solution (see fig. 7 and 8) of the background art, on one hand, the hydrogen flow channel 9 is more complicated to arrange, which increases the complexity of the system; on the other hand, in the power generation mode, the fuel 11 and the heat pipe 1 transfer heat by radiation, and the heat transfer efficiency is poor. Compared with the prior art, the scheme provided by the invention simplifies the arrangement of the hydrogen gas flow passage 9 on one hand, and improves the heat transfer efficiency between the fuel block and the heat pipe 1 on the other hand.

Drawings

FIG. 1 is a schematic illustration of a dual mode spatial nuclear reactor core according to an embodiment of the present invention;

FIG. 2 is an axial cross-sectional schematic view of a dual mode spatial nuclear reactor core according to an embodiment of the present invention;

FIG. 3 is a schematic view of an outer ring fuel 4 according to an embodiment of the present invention;

FIG. 4 is a schematic illustration of the inner ring fuel 5 in accordance with an embodiment of the present invention;

FIG. 5 is a schematic cross-sectional view of the active area of the ALERT core of the prior art;

FIG. 6 is a schematic diagram of a HBS fuel and heat pipe arrangement in the background art;

FIG. 7 is a schematic diagram of a heat pipe structure according to a third embodiment of the present invention;

FIG. 8 is a schematic diagram of a fuel and heat pipe arrangement of a third prior art approach;

in the figure: 1-heat pipe, 2-control drum, 3-radial reflecting layer, 4-outer ring fuel, 5-inner ring fuel, 6-safety rod channel, 7-neutron absorber, 8-heat pipe channel, 9-hydrogen flow channel, 10-axial reflecting layer, 11-fuel, 12-double-layer container, 13-double-layer cladding heat pipe and 14-heat pipe fin.

Detailed Description

The invention is further described below with reference to the figures and examples.

As shown in fig. 1 and 2, the dual-mode spatial nuclear reactor core provided by the invention comprises a fuel block provided with a heat pipe 1 and a hydrogen flow channel 9, wherein hydrogen can be heated by the fuel block through the hydrogen flow channel 9 and then sprayed out as power, and meanwhile, the hydrogen can also generate a cooling effect on the fuel block.

The fuel block is a cylindrical fuel block formed by an inner ring fuel 5 (see fig. 4) and an outer ring fuel 4 (see fig. 3) together, and the outer ring fuel 4 surrounds the periphery of the inner ring fuel 5;

a heat pipe channel 8 is arranged on the outer ring fuel 4, a heat pipe 1 is arranged in the heat pipe channel 8, and the top end of the heat pipe 1 extends out of the top end of the outer ring fuel 4 (namely, is positioned out of the top end of the fuel block);

the reactor core also comprises a radial reflecting layer 3 arranged on the periphery of the outer ring fuel 4, wherein the radial reflecting layer 3 is used for reflecting fission neutrons to the fuel blocks so as to reduce the neutron leakage rate of the reactor core; the reactor is characterized by further comprising a plurality of control drums 2 arranged in the radial reflecting layer 3, wherein the control drums 2 can be used for starting, power adjusting and stopping of a reactor, the control drums 2 are cylindrical and parallel to the axis of a fuel block, the main body of each control drum 2 is a reflector, a neutron absorber 7 is arranged on part of the side surface of each control drum 2, and the neutron absorber 7 is used for absorbing fission and diffusion neutrons in the fuel block; when the neutron absorber 7 faces the fuel block as the control drum 2 rotates, the reactivity of the core can be reduced; when all the neutron absorbers 7 on all the control drums 2 face the fuel blocks, the reactor is shut down, and otherwise, the reactor is started and power is adjusted.

A plurality of hydrogen flow channels 9 (not shown in the drawings) are provided as first hydrogen flow channels in the radial reflective layer 3 and the control drum 2, parallel to the axis of the fuel briquette;

the outer ring fuel 4 and the inner ring fuel 5 are both provided with a plurality of blocks, each outer ring fuel 4 and each inner ring fuel 5 are provided with a plurality of hydrogen flow channels 9, and the hydrogen flow channels 9 are parallel to the axis of the fuel block and penetrate through the fuel block (the top ends of the hydrogen flow channels 9 are positioned at the top end of the fuel block, and the bottom ends of the hydrogen flow channels 9 are positioned at the bottom end of the fuel block). The hydrogen flow channel 9 on the outer ring fuel 4 is a second hydrogen flow channel, and the hydrogen flow channel 9 on the inner ring fuel 5 is a third hydrogen flow channel;

the bottom end of the first hydrogen flow channel is communicated with the bottom end of the second hydrogen flow channel, and the top end of the second hydrogen flow channel is communicated with the top end of the third hydrogen flow channel; when hydrogen is sprayed out from the fuel block as power, the hydrogen firstly flows into the bottom end of the second hydrogen flow channel from top to bottom from the bottom end of the first hydrogen flow channel, and the radial reflecting layer 3 and the control drum 2 can be cooled in the process; then flows into the second hydrogen flow channel from the bottom end of the second hydrogen flow channel and flows into the top end of the third hydrogen flow channel from bottom to top from the bottom end of the second hydrogen flow channel, and the outer ring fuel 4 can be cooled in the process; then flows into the third hydrogen flow channel from the top to the bottom, and the hydrogen is heated by the fuel 5 at the inner ring in the process and then is sprayed out from the bottom of the third hydrogen flow channel.

The top end of the fuel block is provided with an axial reflecting layer 10, and the hydrogen gas flow passage 9 and the heat pipe passage 8 penetrate through the axial reflecting layer 10.

The material of the fuel block is tungsten-based CERMET fuel; the outer surface of the fuel block and the surface of the hydrogen flow channel 9 are provided with tungsten-rhenium alloy coatings.

The working medium inside the heat pipe 1 is sodium or lithium (selected according to the actual operation temperature requirement).

The cladding material of the heat pipe 1 is refractory metal alloy, and the refractory metal alloy comprises molybdenum-rhenium alloy or tungsten-rhenium alloy and the like.

The axial center position of the fuel block (also the axial center of the inner ring fuel 5) is provided with a safety rod channel 6 for accommodating a safety rod, and the safety rod is used for ensuring that the reactor can maintain a subcritical safety state when a launching and dropping accident occurs.

The operating mode of the reactor core of the dual-mode space nuclear reactor provided by the invention can be divided into a propulsion mode and a power generation mode (the switching between the two modes can be realized by adjusting the control drum 2 and the flow of the hydrogen working medium), and the operating mode comprises the following specific steps:

1) in the propulsion mode, the reactor core operates at a higher power level, the hydrogen working medium flows through the first hydrogen flow channel (the radial reflecting layer 3 and the hydrogen flow channel 9 in the control drum 2) from top to bottom, and the radial reflecting layer 3 and the control drum 2 are cooled and preheated in the process; then, the hydrogen working medium flows through a second hydrogen flow channel (a hydrogen flow channel 9 in the outer ring fuel 4) from bottom to top, and the process cools the outer ring fuel 4 and heats the hydrogen working medium to a moderate temperature; then, the hydrogen working medium flows through the third hydrogen flow channel (the hydrogen flow channel 9 of the inner ring fuel 5) from top to bottom, and the process enables the hydrogen working medium to be heated to a very high temperature and then discharged through the spray pipe, so that thrust is generated. The hydrogen flowing mode can make the temperature of the outer ring fuel 4 far lower than that of the inner ring fuel 5, and the heat pipe 1 is arranged in the outer ring fuel 4 and can safely operate under the proper temperature condition. The heat pipe 1 takes out part of the core heat and transfers the heat to the out-of-core thermoelectric conversion system for power generation.

2) In the power generation mode, the discharge of hydrogen working media is stopped, the reactor core operates at a lower power level, and all heat generated by the fuel blocks is taken out of the reactor core by the heat pipes 1 (the heat of the fuel 5 at the inner ring is transferred to the fuel 4 at the outer ring in a heat conduction mode and is taken out of the reactor core by the heat pipes 1) and is transferred to the thermoelectric conversion system outside the reactor for power generation. Due to the low core power, the heat pipe 1 can be safely operated under the proper temperature condition.

It should be noted that the arrangements shown in fig. 1 and 2 are only schematic arrangements, and specific core structures, such as the number and arrangement of the outer ring fuel 4 and the inner ring fuel 5, and the number of hydrogen flow channels 9 and the number of heat pipes 1, etc., need to be designed according to specific system parameter requirements.

The device according to the present invention is not limited to the embodiments described in the specific embodiments, and those skilled in the art can derive other embodiments according to the technical solutions of the present invention, and also belong to the technical innovation scope of the present invention.