Auxiliary thawing loop system of a lithium-cooled space reactor power system and thawing method thereof

Abstract

The application discloses a kind of lithium cold space reactor power system auxiliary thawing loop system and thawing method thereof, lithium cold space reactor power system is composed of one loop system and two loop systems.Lithium cold space reactor power system is thawed by auxiliary loop system, and auxiliary loop system is composed of auxiliary pipeline, auxiliary electromagnetic pump, auxiliary energy conversion unit.After the auxiliary pipeline comes out from reactor core, it is attached to the outer wall of one loop pipeline and two loop pipeline, for heating coolant pipeline.When thawing starts, core is operated at low power level;The heat generated is taken out of the core by the auxiliary loop system, heats up each component of lithium cold space reactor power system along the auxiliary pipeline, melts lithium working medium in each component, and after one loop system and two loop systems are completely thawed, lithium working medium starts to flow, the thawing process is completed, and lithium cold space reactor power system has the conditions for normal operation.The auxiliary loop system can take out the decay heat of the reactor core after the reactor is shut down, as a means of residual heat removal of the core.The auxiliary electromagnetic pump and the auxiliary energy conversion unit can provide working medium circulation and power generation functions respectively during the thawing process or after shutdown.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nuclear reactor power supply system, in particular to an auxiliary thawing loop system of a lithium-cooled space reactor power supply system and a thawing method thereof. BACKGROUND

[0002] Alkali metal lithium has a low vapor pressure, a high specific heat capacity, and a relatively low density compared to other alkali metals such as sodium and potassium. When used as a cooling medium for a lithium-cooled space reactor power supply, the lithium-cooled space reactor power supply has good inherent safety characteristics and a modular design concept, and has potential applicability and application value in deep space exploration, space power supply, planetary surface energy supply, and nuclear batteries.

[0003] Alkali metal lithium has a high melting point of 454K and is solid at room temperature. When a lithium-cooled reactor is used as a space nuclear power supply, the nuclear power supply is in a space environment of 4K, and is affected by solar radiation, earth infrared radiation, and earth reflection. The temperature environment of the nuclear source is lower than the melting point of the alkali metal. Therefore, when the lithium-cooled space reactor power supply is launched from the ground to normal on-orbit flight, the lithium working medium is in a solid state. During on-orbit operation, in order to ensure that the lithium-cooled space reactor power supply system can be normally started and operated, the working medium needs to be thawed before starting to melt the alkali metal lithium, form a circulating loop in the loop, and normally carry away the heat generated by the core.

[0004] In order to heat the alkali metal lithium working medium from a solid state to a molten liquid state, the carrier of the reactor power supply needs to provide a large amount of energy supply for thawing, which cannot be met in engineering practice. SUMMARY

[0005] In order to solve the problem of the need for thawing of the lithium-cooled space reactor, the purpose of the present application is to provide an auxiliary thawing loop system of a lithium-cooled space reactor power supply system and a thawing method thereof, which utilizes the nuclear heating of the lithium-cooled space reactor power supply itself and uses an auxiliary loop system to thaw the entire system, thereby providing a solution for the actual construction and operation of the lithium-cooled space reactor.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0007] An auxiliary thawing loop system of a lithium cooled space reactor power system, wherein the lithium cooled space reactor power system is composed of a primary loop system and a secondary loop system, the primary loop system is sequentially composed of a reactor core 1, a gas-liquid separator 2, a hot end of an energy conversion unit 4 and a primary loop main electromagnetic pump 3 connected by a primary loop pipeline 5; the secondary loop system is sequentially composed of a cold end of the energy conversion unit 4, a secondary loop electromagnetic pump 6 and a heat pipe radiator 7 connected by a secondary loop pipeline 8; the lithium cooled space reactor power system is thawed by the auxiliary loop system, the auxiliary loop system is composed of an auxiliary pipeline 9 and an auxiliary electromagnetic pump 10 and an auxiliary energy conversion unit 11 arranged on the auxiliary pipeline 9; the auxiliary pipeline 9 is tightly attached to the outer wall of the primary loop pipeline 5 and the secondary loop pipeline 8 after leaving the reactor core 1, and is used for heating the coolant pipeline to melt the lithium working medium in the pipeline; the auxiliary loop system can take out the decay heat of the reactor core 1 after the reactor is shut down, and is used as a residual heat removal means of the core; the auxiliary electromagnetic pump 10 and the auxiliary energy conversion unit 11 of the auxiliary loop system can provide working medium circulation and power generation functions respectively during the thawing process or after the reactor is shut down; the energy required for thawing comes from the nuclear heating power of the lithium cooled space reactor power system itself.

[0008] The coolant of the auxiliary loop system is sodium-potassium alloy, which has a low melting point (260K) and acts immediately after the reactor is started.

[0009] The coolant of the secondary loop system is lithium or sodium-potassium alloy or water or silicon oil.

[0010] The energy conversion unit 4 is a thermoelectric power generation unit or a Stirling engine or a Brayton cycle or a Rankine cycle; when a small electric power output is required and the reliability is high and there is no rotating part, a thermoelectric power generation unit is selected; when a large electric power output is required, a more effective dynamic power conversion such as a Stirling engine, a Brayton cycle or a Rankine cycle is selected.

[0011] The auxiliary energy conversion unit 11 is a thermoelectric power generation unit; when the core heat taken out by the auxiliary loop system is small, a thermoelectric power generation unit with static energy conversion mode is adopted; the generated electric energy can be used for other electric units of the lithium cooled space reactor power system.

[0012] The auxiliary pipeline 9, the primary loop pipeline 5 and the secondary loop pipeline 8 are all circular pipes; the auxiliary pipeline 9 is tightly attached to the outer wall of the primary loop pipeline 5 and the secondary loop pipeline 8; in order to strengthen the heat transfer capacity between the outer walls of the pipelines, a high thermal conductivity thermal interface material 12 is welded at the attachment position of the outer walls of the pipelines; the outer side of the attached pipelines is covered by multiple layers of insulation material 13, which has high thermal resistance and low surface emissivity, and plays a role of heat preservation and insulation.

[0013] The number of the auxiliary loop systems is consistent with the number of the loop systems, and the auxiliary loop systems have a redundant design, so that when one of the auxiliary loop systems fails, the whole thawing process is not affected.

[0014] The thawing method of the auxiliary thawing loop system of the lithium-cooled space reactor power system comprises the following steps: at the beginning of thawing, the reactor core is controlled to operate at a low power level by controlling the reactivity of the reactor core 1; the generated heat is taken out of the reactor core by the auxiliary loop system, and is used to heat each component of the primary loop system and the secondary loop system along the auxiliary pipeline 9, so that the lithium working medium in each component is melted; after the primary loop system and the secondary loop system are completely thawed, the lithium working medium starts to flow and form a circulation, and the thawing process is ended, and the power system normally operates.

[0015] Beneficial effects:

[0016] The present application brings the following beneficial effects:

[0017] 1) The system and method of the present application can thaw the reactor power system by means of the auxiliary loop system, and the energy required for thawing comes from the nuclear heating power of the reactor power itself, without the need for the carrier of the reactor power system to provide additional energy supply, thereby saving huge energy consumption demand.

[0018] 2) The auxiliary loop system in the present application can not only thaw before the reactor is started, but also can be used as a means for discharging residual heat of the reactor core. When the reactor power system fails or is normally shut down, the auxiliary loop system can continue to guide the decay heat generated by the core according to its characteristics, so as to prevent the core from overheating and melting. The present application provides an important safety guarantee for the reactor power system.

[0019] 3) The cooling of the auxiliary loop system in the present application adopts sodium-potassium alloy, which has a low melting point and can be in a thawing state in a complex space environment without the need for additional thawing process. The method well utilizes the differences in characteristics between different alkali metals to obtain an optimized working medium matching. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a schematic diagram of the auxiliary thawing loop system of the lithium-cooled space reactor power system of the present application.

[0021] Figure 2 It is a schematic diagram of the auxiliary pipeline and the primary loop and secondary loop pipelines of the present application.

[0022] In the figure: 1 - reactor core; 2 - gas-liquid separator; 3 - primary loop main electromagnetic pump; 4 - energy conversion unit; 5 - primary loop pipeline; 6 - secondary loop electromagnetic pump; 7 - heat pipe radiator; 8 - secondary loop pipeline; 9 - auxiliary pipeline; 10 - auxiliary electromagnetic pump; 11 - auxiliary energy conversion unit; 12 - thermal interface material; 13 - multi-layer insulation material. DETAILED DESCRIPTION

[0023] The auxiliary thawing loop system of the lithium-cooled space reactor power supply system and the thawing method thereof will be further described in detail below in combination with the accompanying drawings shown in Figure 1 , Figure 2

[0024] The auxiliary thawing loop system of the lithium-cooled space reactor power supply system and the thawing method thereof will be further described in detail below in combination with the accompanying drawings shown inThe lithium-cooled reactor power supply system is composed of a primary loop system and a secondary loop system. The primary loop system is composed of a reactor core 1, a gas-liquid separator 2, a primary loop main electromagnetic pump 3, a hot end of an energy conversion unit 4, and a primary loop pipeline 5. The primary loop pipeline 5 connects the reactor core 1, the gas-liquid separator 2, the hot end of the energy conversion unit 4, and the primary loop main electromagnetic pump 3 in sequence. The secondary loop system is composed of a secondary loop electromagnetic pump 6, a cold end of the energy conversion unit 4, a heat pipe radiator 7, and a secondary loop pipeline 8. The secondary loop pipeline 8 connects the cold end of the energy conversion unit 4, the secondary loop electromagnetic pump 6, and the heat pipe radiator 7 in sequence. The lithium-cooled reactor power supply system is thawed by the auxiliary loop system. The auxiliary loop system is composed of an auxiliary pipeline 9, an auxiliary electromagnetic pump 10, and an auxiliary energy conversion unit 11. After the auxiliary pipeline 9 comes out of the reactor core 1, it is tightly attached to the outer walls of the primary loop pipeline 5 and the secondary loop pipeline 8, and is used to heat the coolant pipeline to melt the lithium working substance in the pipeline. The auxiliary loop system can carry out the decay heat of the reactor core 1 after the reactor is shut down, and is used as a residual heat removal means of the core. The auxiliary electromagnetic pump 10 and the auxiliary energy conversion unit 11 of the auxiliary loop system can provide working substance circulation and power generation functions respectively during the thawing process or after the reactor is shut down. The energy required for thawing comes from the nuclear heating power of the lithium-cooled space reactor power supply system itself.

[0025] As a preferred embodiment of the present application, the coolant of the auxiliary loop system is a sodium-potassium alloy, which has a low melting point (260K) and functions immediately after the reactor is started.

[0026] As a preferred embodiment of the present application, the coolant of the secondary loop system is lithium or a sodium-potassium alloy or water or silicon oil.

[0027] As a preferred embodiment of the present application, the energy conversion unit 4 is a thermoelectric generator or a Stirling engine or a Brayton cycle or a Rankine cycle, when the required output electric power is small and the reliability is high and there is no rotating part, a thermoelectric generator is selected; the thermoelectric generator can generate electric energy only by relying on the temperature difference between the hot end and the cold end, without the need for fluid flow and pump driving, and can realize static conversion of heat and electricity. When the required output electric power is large, a more effective dynamic power conversion is selected, such as a Stirling engine, a Brayton cycle or a Rankine cycle; the dynamic conversion unit has high conversion efficiency of heat and electricity, and can output higher electric power under the same heat power to meet the demand for large power.

[0028] As a preferred embodiment of the present application, the auxiliary energy conversion unit 11 is a thermoelectric generator, the auxiliary loop system carries out a small amount of heat from the reactor core, and a thermoelectric generator with static energy conversion is used; the generated electric energy can be used for other electric units of the lithium-cooled space reactor power supply system.

[0029] As shown in Figure 2 As a preferred embodiment of the present application, the auxiliary pipe 9, the primary loop pipe 5 and the secondary loop pipe 8 are all circular pipes, the auxiliary pipe 9 is tightly attached to the outer walls of the primary loop pipe 5 and the secondary loop pipe 8, high-thermal-conductivity thermal interface material 12 is welded at the attachment of the outer walls of the pipes to strengthen the heat transfer capacity between the outer walls of the pipes, and the outer sides of the attached pipes are covered by multilayer insulation material 13, which has high thermal resistance and low surface emissivity, and plays a role of heat preservation and insulation.

[0030] As a preferred embodiment of the present application, the number of the auxiliary loop systems is consistent with the number of the primary loop systems, and the design has redundancy, so that when one of the auxiliary loop systems fails, the entire thawing process will not be affected.

[0031] The thawing method of the auxiliary thawing loop system of the lithium-cooled space reactor power supply system of the present application is as follows: at the beginning of thawing, the reactivity of the reactor core 1 is controlled to make the reactor core operate at a low power level; the generated heat is carried out of the reactor core by the auxiliary loop system, heats each component of the primary loop system and the secondary loop system along the auxiliary pipe 9, and melts the lithium working medium in each component; after the primary loop system and the secondary loop system are completely thawed, the lithium working medium starts to flow and form a circulation, the thawing process ends, and the power supply system operates normally.

[0032] The part not described in detail in the present application is common knowledge to those skilled in the art.

Claims

1. An auxiliary thawing circuit system for a lithium-cooled space reactor power system, characterized by: The lithium-cooled space reactor power supply system is composed of a primary loop system and a secondary loop system. The primary loop system is composed of a reactor core (1), a gas-liquid separator (2), a hot end of an energy conversion unit (4) and a primary loop main electromagnetic pump (3) connected via a primary loop pipe (5); the secondary loop system is composed of a cold end of an energy conversion unit (4), a secondary loop electromagnetic pump (6) and a heat pipe radiator (7) connected via a secondary loop pipe (8); the lithium-cooled space reactor power supply system relies on an auxiliary loop system for defrosting, and the auxiliary loop system is composed of an auxiliary pipe (9) and an auxiliary electromagnetic pump (10) arranged on the auxiliary pipe (9) and The auxiliary circuit system is composed of an auxiliary energy conversion unit (11); after the auxiliary pipe (9) comes out of the reactor core (1), it is closely attached to the outer wall of the primary circuit pipe (5) and the secondary circuit pipe (8) to heat the coolant pipe and melt the lithium working medium in the pipe; after the reactor is shut down, the auxiliary circuit system takes out the decay heat of the reactor core (1) as a means of discharging residual heat of the core; the auxiliary electromagnetic pump (10) and the auxiliary energy conversion unit (11) of the auxiliary circuit system respectively provide the functions of working medium circulation and power generation during the thawing process or after the shutdown; the energy required for thawing comes from the nuclear heating power of the lithium-cooled space reactor power supply system itself.

2. The auxiliary thawing circuit system of a lithium-cooled space reactor power system according to claim 1, characterized in that: The coolant of the auxiliary loop system is a sodium-potassium alloy, which has a low melting point and takes effect immediately after the reactor is started.

3. The auxiliary thawing circuit system of a lithium-cooled space reactor power system according to claim 1, characterized in that: The coolant of the secondary circuit system is lithium, sodium-potassium alloy, water or silicone oil.

4. The auxiliary thawing circuit system of a lithium-cooled space reactor power system according to claim 1, characterized in that: The energy conversion unit (4) is a thermoelectric power generation unit, a Stirling motor, a Brayton cycle, or a Rankine cycle. When the output power is required to be small, the reliability is high, and there are no rotating parts, the thermoelectric power generation unit is selected; when the output power is required to be large, more efficient dynamic power conversion is selected, and a Stirling motor, a Brayton cycle, or a Rankine cycle is selected.

5. The auxiliary thawing circuit system and thawing method of a lithium-cooled space reactor power system according to claim 1, characterized in that: The auxiliary energy conversion unit (11) is a thermoelectric power generation unit. The auxiliary loop system brings out little core heat, and a thermoelectric power generation unit in a static energy conversion mode is used. The generated electric energy is used for other power units of the lithium-cooled space reactor power system.

6. The auxiliary thawing circuit system of a lithium-cooled space reactor power system according to claim 1, characterized in that: The auxiliary pipe (9), the primary-loop pipe (5) and the secondary-loop pipe (8) are all circular pipes. The auxiliary pipe (9) is closely attached to the outer walls of the primary-loop pipe (5) and the secondary-loop pipe (8). In order to enhance the heat transfer capability between the outer walls of the pipes, a thermal interface material (12) with high thermal conductivity is welded at the joint of the outer walls of the pipes. The outer side of the entire jointed pipe is covered with a multi-layer insulation material (13). The multi-layer insulation material (13) has high thermal resistance and low surface emissivity, thereby playing a role in heat preservation and insulation.

7. The auxiliary thawing circuit system of a lithium-cooled space reactor power system according to claim 1, characterized in that: The number of the auxiliary circuit systems is consistent with the number of the primary circuit systems, and a redundant design is provided. When one of the auxiliary circuit systems fails, the entire thawing process will not be affected.

8. The thawing method of the auxiliary thawing circuit system of a lithium-cooled space reactor power system according to any one of claims 1 to 7, characterized in that: The thawing method comprises the following steps: when thawing begins, the reactivity of the reactor core (1) is controlled so that the reactor core operates at a low power level; the generated heat is taken out of the reactor core by the auxiliary loop system, and is heated along the auxiliary pipeline (9) to heat various components of the primary loop system and the secondary loop system, so that the lithium working medium in each component melts; after the primary loop system and the secondary loop system are completely thawed, the lithium working medium begins to flow and forms a cycle, the thawing process ends, and the power supply system operates normally.

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