Passive Residual Heat Removal System for Liquid Metal Cooled Reactor

Abstract

The present application provides a passive residual heat removal system for a liquid metal cooled reactor. The passive residual heat removal system includes an independent heat exchanger, an air cooler, an intermediate circuit, and a plurality of Stirling thermoelectric converters. The air cooler includes a damper. The hot end of the Stirling thermoelectric converter is inserted into the air cooler for heat exchange with the intermediate circuit. The adiabatic end of the Stirling thermoelectric converter is located on the inner wall surface of the air cooler, and the cold end of the Stirling thermoelectric converter is located outside the inner wall surface of the air cooler. When an accident causes a power outage, the damper automatically opens, and electricity is generated by using the temperature difference between the cold end and the hot end of the Stirling thermoelectric converter for emergency equipment applications. By adding Stirling thermoelectric converters to the passive residual heat removal system, the present application fully utilizes the advantage of the relatively high temperature of the liquid metal coolant in the liquid metal cooled reactor, enabling the Stirling thermoelectric converter to generate electricity using the residual heat for use by emergency equipment in the nuclear power plant, and reducing the complexity of the nuclear power system.

Description

Technical Field

[0001] The present application belongs to the technical field of liquid metal cooled reactors, and in particular relates to a passive residual heat removal system of a liquid metal cooled reactor. Background Art

[0002] With the gradual maturity of nuclear power system technology, nuclear power systems represented by liquid metal cooled reactors such as sodium-cooled fast reactors have developed rapidly, which has put forward great demands on the safety of liquid metal cooled reactors. Reliable, passive and safe passive residual heat removal system is a key component of liquid metal cooled reactors.

[0003] At present, the passive residual heat removal system of the liquid metal cooled reactor partially or completely adopts the design of an intermediate loop coupled air cooler, and uses the damper of the air cooler to control the start time of the accident residual heat removal of the liquid metal cooled reactor. In the event of a power outage in the entire plant, the nuclear power plant must use emergency diesel engines for power supply, and the system is relatively complex. Summary of the invention

[0004] In view of this, an embodiment of the present application is committed to providing a passive waste heat removal system for a liquid metal cooled reactor. By adding a Stirling thermoelectric converter to the passive waste heat removal system, the advantage of the higher temperature of the liquid metal coolant in the liquid metal cooled reactor is fully utilized, so that the Stirling thermoelectric converter can use waste heat to generate electricity to supply emergency equipment in the nuclear power plant, thereby reducing the complexity of the nuclear power system.

[0005] The present application provides a passive residual heat removal system for a liquid metal cooled reactor, which includes an independent heat exchanger, an air cooler, an intermediate loop and a plurality of Stirling thermoelectric converters. The independent heat exchanger is configured to perform heat exchange on the heat generated by the liquid metal cooled reactor. The air cooler includes a damper. The inlet end of the air cooler is connected to the outlet end of the independent heat exchanger. The intermediate loop is connected between the outlet end of the air cooler and the inlet end of the independent heat exchanger. The hot end of the Stirling thermoelectric converter is inserted into the air cooler to exchange heat with the intermediate loop, the insulated end of the Stirling thermoelectric converter is located on the inner wall surface of the air cooler, and the cold end of the Stirling thermoelectric converter is located on the outer side of the inner wall surface of the air cooler. The operation of the Stirling thermoelectric converter is controlled by the opening and closing of the damper of the air cooler. When an accident occurs and causes a power outage, the damper automatically opens, and the temperature difference between the cold end and the hot end of the Stirling thermoelectric converter is used to generate electricity for emergency equipment application.

[0006] In the above solution, by adding multiple Stirling thermoelectric converters to the passive residual heat removal system of a liquid metal cooled reactor, when an accident causes a power outage, the air damper is automatically opened. The cold end of the Stirling thermoelectric converter exchanges heat with air convection, and the temperature decreases. The hot end of the Stirling thermoelectric converter absorbs the heat of the intermediate loop, resulting in a large temperature difference between the cold end and the hot end of the Stirling thermoelectric converter, causing power generation. The generated electricity is sufficient to supply emergency equipment, and at the same time, residual heat removal and emergency power supply are achieved, reducing the complexity of the nuclear power system and improving the reliability of the nuclear power system.

[0007] In a specific embodiment of the present application, the liquid metal cooled reactor is a pool-type sodium cooled fast reactor. The independent heat exchanger is configured to be located inside the liquid metal cooled reactor. The working medium of the Stirling thermoelectric converter is sodium.

[0008] In a specific embodiment of the present application, the lowest threshold of the operating temperature range of the Stirling thermoelectric converter is not less than the outlet temperature of the liquid metal cooled reactor.

[0009] In a specific embodiment of the present application, the liquid metal cooled reactor is a pool-type sodium cooled fast reactor, and the operating temperature range of the Stirling thermoelectric converter is above 550 °C. Description of the Drawings

[0010] Figure 1 The figure shows a schematic structural diagram of a passive residual heat removal system of a liquid metal cooled reactor provided by an embodiment of the present application. Detailed Embodiments

[0011] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0012] As Figure 1As shown in the figure, the passive residual heat removal system 100 of the liquid metal cooled reactor 10 includes an independent heat exchanger 1, an air cooler 2, an intermediate circuit 3, and a plurality of Stirling thermoelectric converters 4. The independent heat exchanger 1 is configured to perform heat exchange on the heat generated by the liquid metal cooled reactor. The air cooler 2 includes a damper 21. The inlet end of the air cooler 2 is connected to the outlet end of the independent heat exchanger 1. The intermediate circuit 3 is connected between the outlet end of the air cooler 2 and the inlet end of the independent heat exchanger 1. The hot end A of the Stirling thermoelectric converter 4 is inserted into the air cooler 2 for heat exchange with the intermediate circuit 3. The adiabatic end B of the Stirling thermoelectric converter 4 is located on the inner wall surface of the air cooler 2. The cold end C of the Stirling thermoelectric converter 4 is located outside the inner wall surface S of the air cooler 2. The operation of the Stirling thermoelectric converter 4 is controlled by the opening and closing of the damper 21 of the air cooler 2. When an accident causes a power outage, the damper 21 automatically opens, and electricity is generated by using the temperature difference between the cold end C and the hot end A of the Stirling thermoelectric converter 4 for emergency equipment applications. In this way, by adding a plurality of Stirling thermoelectric converters 4 to the passive residual heat removal system 100 of the liquid metal cooled reactor, when an accident causes a power outage, the damper 21 is automatically opened. The cold end C of the Stirling thermoelectric converter 4 exchanges heat with the air by convection, and the temperature decreases. The hot end A of the Stirling thermoelectric converter 4 absorbs the heat of the intermediate circuit 3, resulting in a large temperature difference between the cold end C and the hot end A of the Stirling thermoelectric converter 4, causing electricity generation, and the generated electricity is sufficient for emergency equipment applications. In addition, the cold end C of the Stirling thermoelectric converter 4 provided on the air cooler 2 and the independent heat exchanger 1 jointly drive the intermediate circuit 3 to generate natural circulation, so that residual heat removal and emergency power supply can be carried out simultaneously, reducing the complexity of the nuclear power system and improving the reliability of the nuclear power system, and having broad application prospects in the passive residual heat removal system of fast reactors that use the intermediate circuit 3 to couple the air cooler 2.

[0013] It should be noted that when the liquid metal cooled reactor 10 is operating normally, the damper 21 of the air cooler 2 is in the closed state, the air cooler 2 is not started, and the temperature difference between the cold end C and the hot end A of the Stirling thermoelectric converter 4 is small, and it does not absorb heat for power generation. In addition, after an accident causes a power outage, the damper 21 can be automatically opened, and the Stirling thermoelectric converter is automatically put into use to provide off-site power, generate electricity and discharge heat at the same time.

[0014] The Stirling thermoelectric converter 4 is a device that converts thermal energy into electrical energy using the thermoelectric effect. The working principle of the Stirling thermoelectric converter 4 is based on the thermodynamic principle of the Stirling cycle, that is, thermal energy is generated by the temperature difference between two heat sources at different temperatures. The greater the temperature difference between the cold end C and the hot end A of the Stirling thermoelectric converter 4, the higher the power generation efficiency.

[0015] In the passive residual heat removal system 100 of the liquid metal cooled reactor provided by at least one embodiment of the present application, the liquid metal cooled reactor 10 is a pool-type sodium cooled fast reactor. The independent heat exchanger 1 is configured to be located within the liquid metal cooled reactor 10. The working fluid of the Stirling thermoelectric converter 4 is sodium. Thus, when the passive residual heat removal system 100 is applied to the field of pool-type sodium cooled fast reactors, in the event of an accident (such as a station blackout accident, etc.) in a large pool-type sodium cooled fast reactor, the air damper 21 automatically opens after power failure. The Stirling thermoelectric converter 4 generates electricity from the loop heat to provide emergency power. The temperature of the fluid in the air cooler 2 decreases, forming a natural circulation loop with the high-temperature fluid in the independent heat exchanger 1 within the pool-type sodium cooled reactor, continuously carrying the heat to the air cooler 2 for discharge. This enables the passive residual heat removal system of the pool-type sodium cooled fast reactor to simultaneously remove residual heat during an accident and generate electricity using the residual heat for the use of emergency equipment within the power plant. The passive residual heat removal system 100 can be used for the residual heat removal systems of various sodium cooled fast reactors.

[0016] The working temperature range of the Stirling thermoelectric converter 4 only needs to be adapted to the outlet temperature of the reactor. On this basis, the embodiments of the present application do not specifically limit the working temperature range of the Stirling thermoelectric converter 4. In some embodiments, if the liquid metal cooled reactor is a pool-type sodium cooled fast reactor and the outlet temperature of the sodium cooled fast reactor is approximately 550 °C, then the working temperature range of the Stirling thermoelectric converter 4 is above 550 °C. In some other embodiments, if the liquid metal cooled reactor is a lead alloy liquid metal cooled fast reactor and the outlet temperature of the lead alloy liquid metal cooled fast reactor is approximately 550 °C, then the working temperature range of the Stirling thermoelectric converter 4 is above 550 °C.

[0017] It should be noted that the combination manner of the various technical features in the embodiments of the present application is not limited to the combination manner recorded in the embodiments of the present application or the combination manner recorded in the specific embodiments. All the technical features recorded in the present application can be freely combined or combined in any manner, unless contradictions occur between them.

[0018] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, etc. made within the spirit and principles of the present application shall be included within the protection scope of the present application.

Claims

1. An passive residual heat removal system for a liquid metal cooled reactor, characterized in that Comprising: An independent heat exchanger configured to perform heat exchange on the heat generated by the liquid metal cooled reactor; An air cooler including a damper, wherein the inlet end of the air cooler is connected to the outlet end of the independent heat exchanger; An intermediate loop connected between the outlet end of the air cooler and the inlet end of the independent heat exchanger; A plurality of Stirling thermoelectric converters, the hot ends of which are inserted into the air cooler to exchange heat with the intermediate loop, the adiabatic ends are located on the inner wall surface of the air cooler, and the cold ends are located outside the inner wall surface of the air cooler. Wherein, the operation of the Stirling thermoelectric converter is controlled by the opening and closing of the damper of the air cooler. When a power failure occurs due to an accident, the damper automatically opens, the cold ends of the Stirling thermoelectric converters exchange heat by convection with the air, the hot ends of the Stirling thermoelectric converters absorb the heat of the intermediate loop, and electricity is generated by using the temperature difference between the cold ends and the hot ends of the Stirling thermoelectric converters for emergency equipment applications.

2. The passive residual heat removal system according to claim 1, wherein The liquid metal cooled reactor is a pool-type sodium cooled fast reactor, the independent heat exchanger is configured to be located inside the liquid metal cooled reactor, and the working medium of the Stirling thermoelectric converter is sodium.

3. The passive residual heat removal system according to claim 1, wherein The lowest threshold of the operating temperature range of the Stirling thermoelectric converter is not less than the outlet temperature of the liquid metal cooled reactor.

4. The passive residual heat removal system according to claim 3, wherein The liquid metal cooled reactor is a pool-type sodium cooled fast reactor, and the operating temperature range of the Stirling thermoelectric converter is above 550 °C.

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