JP2017150742A - Loop heat pipe heat exchange system and loop heat pipe heat exchange system for atomic furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a loop heat pipe heat exchange system which inhibits mixture of a non-condensable gas with a simple and energy saving structure.SOLUTION: A loop heat pipe heat exchange system transports heat by density differences of a working fluid. The system includes: a first heat exchanger 21 provided at a heat source 23 and having a first heat transfer pipe 1; a second heat exchanger 22 provided at a cooling source 24 and having a second heat transfer pipe 11; a first passage 6 connecting an outflow port of the first heat transfer pipe with an inflow port of the second heat transfer pipe; a second passage 7 connecting an outflow port of the second heat transfer pipe with an inflow port of the first heat transfer pipe; and a pressure accumulation tank 17 connected with a middle part of the second passage. The first heat transfer pipe, the second heat transfer pipe, the first passage, the second passage, and a part of the pressure accumulation tank are filled with the working fluid in advance before start of the operation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a loop heat pipe heat exchange system and a reactor loop heat pipe heat exchange system.

  For example, a nuclear reactor system includes a fuel rod sealed with nuclear fuel pellets, a core loaded with a fuel assembly in which fuel rods are bundled, a reactor pressure vessel (pressure vessel) containing the core, and a pressure vessel with an airtight structure. The reactor containment vessel (containment vessel) stored in (1) prevents leakage of radioactive materials outside the reactor.

  The cooling water supplied into the pressure vessel is heated in the reactor core to become steam. Steam is sent from the pressure vessel through the main steam pipe to the turbine and turns the turbine. The steam is condensed by the condenser after turning the turbine, and water is supplied again into the pressure vessel by the water supply pump. The containment vessel is provided with a pressure suppression pool. The pressure suppression pool reduces the pressure in the containment vessel by condensing the steam leaked from the pressure vessel in the event of an accident such as a main steam pipe breakage in the pool water.

  The reactor system includes an emergency core cooling device for cooling the core after the reactor is shut down in response to a failure or the like. The emergency core cooling system includes a high pressure water injection system, a low pressure water injection system, and a reactor isolation cooling system. In the subsequent long-term cooling process, the water level of the pressure vessel and the core are cooled or the pressure suppression pool is cooled by the residual heat removal system. Eventually, the decay heat is radiated to the atmosphere outside the containment vessel, seawater, river water, lake water, etc. as a heat sink.

  If the event of loss of the entire power source continues for a long period of time, the residual heat removal system using an active device such as a pump is difficult to operate sufficiently. Non-Patent Document 1 proposes a system that dissipates decay heat generated in the reactor core to the outside of the containment vessel using a passive device when it is difficult to dissipate the heat to the outside of the containment vessel by the residual heat removal system.

  The “infinite time air cooling system” proposed by Non-Patent Document 1 includes a primary side heat exchanger provided in a pressure vessel and a secondary side heat exchange provided in the atmosphere of a containment vessel outer periphery (container shelter outer periphery). It is a loop heat pipe heat exchange system that communicates with the vessel through a flow path. In this heat exchange system, the water in the primary side heat exchanger evaporates and flows through the flow path due to the heat of the cooling water and steam heated by decay heat, and is cooled and condensed by the secondary side heat exchanger, The condensed water is circulated by gravity to the primary heat exchanger.

  In the above-described heat exchange system, the primary side heat exchanger is installed in the pressure vessel, so that it is required to be small. Furthermore, in the heat exchange system, since the secondary side heat exchanger is an air cooling system having a lower heat transfer coefficient than water cooling, there is a problem of improving the heat transfer performance of the loop heat pipe heat exchanger.

Patent Document 1 describes the influence of the non-condensable gas existing in the heat transfer tube and the flow path of the heat exchanger at the start of the system operation as a main factor of deterioration in the heat transfer performance of the loop heat pipe heat exchange system. Indicates.
In the loop heat pipe heat exchanger, a predetermined amount of refrigerant (cooling water) is filled at the start of operation based on the gas-liquid ratio during operation. For this reason, the mixed gas of a vapor | steam and non-condensable gas occupies the gaseous-phase space of a loop heat pipe heat exchanger. As the concentration of the non-condensable gas increases, the heat transfer rate of the condensation heat decreases in inverse proportion. Furthermore, since the pressure on the condenser side increases due to the partial pressure of the non-condensable gas, the circulation flow rate of the refrigerant vapor decreases. This decrease in the circulation flow rate of the refrigerant vapor also leads to a decrease in heat transfer performance.

  By the way, as described in Patent Document 2, in a condenser that is a component of a cycle such as steam generation, power recovery, steam condensation, and water supply in a steam power generation system, a main condenser and a condenser for discharging non-condensable gas. Some have

  As described in Non-Patent Document 3, a loop heat pipe heat exchange system can be applied to a geothermal binary power generation system as an example of a steam power generation system. In the geothermal binary power generation system, power is generated by rotating a steam turbine by exchanging heat between geothermal steam and hot water with a medium having a relatively low boiling point. In this geothermal binary power generation system, the function performed by the loop heat pipe heat exchange system is to improve power generation efficiency.

  Patent Document 1 discloses a technique for reducing the concentration of a non-condensable gas in a flow path of a loop heat pipe heat exchange system. In the prior art described in Patent Document 1, in the secondary side heat exchanger composed of a lower header, a plurality of condensing tube groups, and an upper header, a part of the condensing tube group is not communicated with the upper header, Connect to separation tube. The non-condensable gas flowing in from the upper header descends in the heat transfer tube of the secondary side heat exchanger together with the condensed water, gas-liquid is separated by the density difference in the lower header, and passes through the heat transfer tube not communicating with the upper header. It rises and is stored in the gas separation pipe. In Patent Document 1, when the pressure of the gas separation pipe reaches a predetermined gas pressure, the valve at the top of the gas separation pipe is opened to discharge the non-condensable gas.

  In Patent Document 2, the non-condensable gas is discharged together with the surplus steam of the main condenser, and the surplus steam is condensed by the condenser for discharging the non-condensable gas. Then, the non-condensable gas remaining in the non-condensable gas condenser is discharged by a vacuum pump or an air ejector.

  In the prior art of Patent Document 3, a non-condensable gas discharge pipe is connected downstream of the lower header of the secondary heat exchanger. In patent document 3, noncondensable gas is discharged | emitted based on the temperature difference of an upper header and a lower header. This utilizes the phenomenon that when the non-condensable gas accumulates in the heat transfer tube of the secondary side heat exchanger, the condensation heat transfer rate decreases and the temperature of the condensate increases.

  Patent Document 4 discloses a loop heat pipe manufacturing technology that eliminates non-condensable gas by sucking the gas phase of a loop heat pipe filled with a predetermined amount of refrigerant with a vacuum pump and caulking and sealing the upper part. Has been.

Japanese Patent No. 1633684 Japanese Patent Laid-Open No. 10-2683 Japanese Patent Laid-Open No. 60-80087 Japanese Patent Application Laid-Open No. 6-229693

Proceedings of the 2014 22nd International Conference on Nuclear Engineering, July 7-11, 2014, Prague, Czech Public, ICONE22-30989 Tamura, et al., The Atomic Energy Society of Japan 2014 Annual Meeting, p. 648 (2014) Mickson, M.M. H. Fanelli, M .; , Introduction to Geothermal Energy, IGA Special Section, Geothermal Society of Japan (2005)

  Since the techniques described in Patent Document 1 and Patent Document 3 described above collect non-condensable gas from flowing coolant and steam, it is difficult to completely remove the non-condensable gas.

  In addition, these conventional technologies open and close the valve based on the measured values of temperature and pressure to discharge non-condensable gas, so if the instrumentation power supply or control power supply that is the power source of the sensor or actuator stops For example, the non-condensable gas cannot be discharged without opening the valve, or the valve may remain open and the loop heat pipe heat exchange system may not function. Therefore, it is not easy to apply the conventional techniques described in Patent Document 1 and Patent Document 3 to a nuclear reactor system that is required to ensure safety.

  The technique described in Patent Document 2 also collects the non-condensable gas from the flowing liquid or the mixed gas with the vapor, so that it is difficult to completely remove the non-condensable gas. Further, in the technique of Patent Document 2, since a vacuum pump and an air ejector are used for discharging non-condensable gas, not only power is consumed to drive them but also the heat removal performance is deteriorated because it cannot be activated when the power is lost. there's a possibility that.

  The technique described in Patent Document 4 relates to a heat transfer element of a loop heat pipe. However, the length of the loop heat pipe that can be manufactured by the method of Patent Document 4 is limited, and is not suitable for transporting heat over a long distance. For example, in a nuclear reactor system, it is necessary to carry and discard heat from a pressure vessel to the outside of a containment vessel. A loop heat pipe that can be used for heat removal over such a long distance is created by the manufacturing method of Patent Document 4. Is difficult.

  Further, as described in Patent Document 4, the gas phase of the tube group type loop heat pipe heat exchange system is sucked by a vacuum pump, and is firstly operated in a high-temperature and high-pressure environment in a pressure vessel during a reactor operation period. Maintaining the negative pressure in the flow path from the side heat exchanger to the secondary side heat exchanger is a heavy maintenance load.

  Similarly, in the steam power generation system, it is difficult to permanently seal the loop from the heating unit to the condensing unit or to suck it with a vacuum pump.

  The present invention has been made in view of the above-described problems, and its object is to provide a loop heat pipe heat exchange system and a reactor loop that can suppress mixing of non-condensable gas with a simple and energy-saving configuration. It is to provide a heat pipe heat exchange system. Another object of the present invention is to suppress the mixing of non-condensable gas and can automatically start even when the power source is lost to transport heat from the heating source to the cooling source. To provide a loop heat pipe heat exchange system and a loop heat pipe heat exchange system for a nuclear reactor.

  In order to solve the above-mentioned problem, a loop heat pipe heat exchange system according to one aspect of the present invention is a loop heat pipe heat exchange system that transports heat due to a density difference of a working fluid, and is provided in a heating source. A first heat exchanger having a heat transfer tube, a second heat exchanger provided in a cooling source and having a second heat transfer tube, an outlet of the first heat transfer tube, and an inlet of the second heat transfer tube are connected to each other. A first flow path, a second flow path that connects the outlet of the second heat transfer pipe and the inlet of the first heat transfer pipe, and a pressure accumulation tank connected in the middle of the second flow path, The heat pipe, the second heat transfer pipe, the first flow path, the second flow path, and a part of the pressure accumulating tank are filled with the working fluid in advance before the operation is started.

  A loop heat pipe heat exchange system for a nuclear reactor according to another aspect of the present invention is a loop heat pipe heat exchange system for use in a nuclear reactor, and the nuclear reactor includes a core equipped with nuclear fuel and a core. A pressure vessel, a main steam pipe for sending steam generated in the reactor core to the turbine, a containment vessel containing the pressure vessel, a dry well which is a space in the containment vessel, and a partial space in the containment vessel are closed spaces A partition, a wet well having a water pool, and a vent pipe communicating with the dry well and the pool water of the wet well, the first heat exchanger having a first heat transfer pipe provided in the pressure vessel, 1 Heat exchanger provided outside the containment vessel at a position higher than the installation position in the height direction of the heat exchanger, the second heat exchanger having the second heat transfer tube, the outlet of the first heat transfer tube, and the flow of the second heat transfer tube First flow connecting the entrance A second flow path connecting the outlet of the second heat transfer tube and the inlet of the first heat transfer pipe, a pressure accumulation tank located outside the containment vessel and connected in the middle of the second flow path, A second isolation valve that is provided in the middle of the two flow paths, is normally closed, and is opened when the drive power supply is stopped. The first heat transfer pipe, the second heat transfer pipe, and the first flow path The second flow path and a part of the pressure accumulating tank are filled with a working fluid in advance.

  A loop heat pipe heat exchange system for a nuclear reactor according to still another aspect of the present invention is a loop heat pipe heat exchange system for use in a nuclear reactor, and the nuclear reactor includes a core equipped with nuclear fuel, and a core including the core. Pressure vessel, a main steam pipe for sending steam generated in the core to the turbine, a containment vessel containing the pressure vessel, a dry well which is a space in the containment vessel, and a partial space in the containment vessel is closed A first well heat exchanger having a first heat transfer pipe provided in the dry well, and a wet well having a water pool, and a vent pipe communicating with the dry well and the pool water of the wet well; A second heat exchanger provided outside the containment vessel at a position higher than the installation position in the height direction of the first heat exchanger and having a second heat transfer tube; an outlet of the first heat transfer tube; and a second heat transfer tube Connect inlet The first flow path, the second flow path connecting the outlet of the second heat transfer tube and the inlet of the first heat transfer pipe, and located outside the containment vessel and connected in the middle of the second flow path A pressure accumulating tank and a second isolation valve provided in the middle of the second flow path, the first heat transfer pipe, the second heat transfer pipe, the first flow path, the second flow path, and a part of the pressure storage tank; , Previously filled with working fluid.

  According to the present invention, the working fluid is filled in part of the first heat transfer tube, the second heat transfer tube, the first flow path, the second flow path, and the pressure accumulation tank, so that the non-condensable gas is operated. It can be removed from the fluid circulation path, and heat transfer performance can be improved. Then, after the operation is started, when the first heat transfer tube is heated by the heating source and a part of the working fluid is changed to steam, the working fluid pushed out by the steam flows into the pressure accumulating tank. Since the gas phase part in the accumulator tank is compressed, the pressurized state is maintained. Thereby, a working fluid can be changed to the state of a gas-liquid two-phase flow, and a state can be maintained. Since mixing of the non-condensable gas into the working fluid is suppressed in advance, it is possible to suppress a decrease in the heat transfer rate of the condensation heat and prevent a decrease in the flow rate of circulating the working fluid.

The lineblock diagram of the loop heat pipe heat conversion system concerning the 1st example. The block diagram of the heat exchange system which concerns on the modification of 1st Example. The block diagram which shows a mode that a cooling water is filled. The block diagram which shows the mode at the time of starting. The block diagram which shows the mode after boiling. The block diagram of the heat exchange system which shows the other modification of 1st Example. The block diagram of the loop heat pipe heat exchange system which concerns on 2nd Example. The block diagram of the loop heat pipe heat exchange system which concerns on 3rd Example. The block diagram which shows the mode at the time of starting. The block diagram which shows a mode when a part of cooling water boils. The block diagram of the heat exchange system which concerns on the modification of 3rd Example. The block diagram of the loop heat pipe heat exchange system which concerns on 4th Example. The block diagram of the heat exchange system which concerns on the modification of 4th Example. The block diagram of the loop heat pipe heat exchange system which concerns on 5th Example. The block diagram of the heat exchange system which concerns on the modification of 5th Example. The block diagram of the loop heat pipe heat exchange system for reactors of 6th Example. The block diagram of the loop heat pipe heat exchange system for reactors of 7th Example. The block diagram of the loop heat pipe heat exchange system for reactors of 8th Example. The block diagram of the loop heat pipe heat exchange system for reactors of 9th Example. The block diagram of the loop heat pipe heat exchange system for reactors of 10th Example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The loop heat pipe heat exchange system according to the present embodiment can be suitably used for, for example, a geothermal binary power generation system or a nuclear reactor system.

  The loop heat pipe heat exchange system according to the present embodiment can be used, for example, as a part of an apparatus that removes nuclear reactor residual heat. According to the present embodiment, the decay heat of the nuclear reactor can be radiated to the heat sink outside the containment vessel at the time of a nuclear reactor failure or accident. Furthermore, according to the present embodiment, even when the reactor external power source and the control power source are lost, the loop heat pipe heat exchange system can be automatically activated to remove heat. Furthermore, according to this embodiment, mixing of the non-condensable gas to the heat exchanger can be prevented in advance, and a decrease in heat removal performance can be suppressed.

  Hereinafter, a reactor system will be described as an example of a heat utilization system to which the loop heat pipe heat exchange system can be applied. In this embodiment, the installation height of the secondary side heat exchanger (second heat exchanger) provided in the cooling source is made higher than the primary side heat exchanger (first heat exchanger) provided in the heating source. . The steam of the working fluid (cooling water) generated in the primary side heat exchanger flows through the flow path to the secondary side heat exchanger installed at a high position and becomes condensed water. The condensed water of the secondary side heat exchanger returns to the flow path toward the primary side heat exchanger at a low position. Thereby, in this embodiment, cooling water is circulated between a primary side heat exchanger and a secondary side heat exchanger using the natural circulation by the density difference of cooling water, and gravity.

  This embodiment can be applied to a reactor residual heat removal system that dissipates the decay heat of nuclear fuel to the outside of the containment vessel after an emergency shutdown of the reactor. In this case, the heating source is steam generated from the core in the pressure vessel or cooling water in the pressure vessel. The heating source may be a gas or cooling water present in the containment vessel dry well space. The heating source may be a gas existing in the containment vessel wet well space or cooling water. The heating source may be the secondary steam of the emergency condenser or the secondary cooling water. The heating source may be a device body of the emergency core cooling water system pump or a gas in the pump chamber.

  Fail-open type automatic valves are provided in the flow path where condensed water returns from the secondary heat exchanger to the primary heat exchanger and the flow path where steam flows from the primary heat exchanger to the secondary heat exchanger. It can also be provided. A flow path through which cooling water or steam circulates between the primary side heat exchanger and the secondary side heat exchanger is referred to as a loop flow path. In the present embodiment, the pressure accumulating tank is connected to the loop flow path located on the outlet side of the secondary side heat exchanger. In this embodiment, before starting the operation of the nuclear reactor, after filling the inside of the heat exchanger, the inside of the loop flow path, and a part of the pressure accumulating tank with cooling water, the automatic valve is closed. .

  When suppressing pulsation, a pulsation suppression mechanism is provided in the condensed water return flow path. The pulsation suppressing mechanism suppresses pulsation by adjusting the cross-sectional area of the condensed water return channel, for example. For example, an orifice giving a pressure loss may be provided in the condensed water return flow path.

  Alternatively, a fail-open type automatic valve having a flow rate adjustment function is provided in the condensed water return flow path, the initial value of the valve opening of the automatic valve is reduced, and the valve is opened after the start of the loop heat pipe heat exchange system. What is necessary is just to set so that a degree may be increased gradually.

  Alternatively, in the middle of the condensed water return flow path, another condensed water return flow path is provided in parallel, and a fail-open type automatic valve is disposed in each of the condensed water return flow paths, and at least one of the plurality of automatic valves. The maximum valve opening degree of one automatic valve may be set smaller than the maximum valve opening degree of another automatic valve. Then, when the loop heat pipe heat exchange system is started up, the automatic valve with the smallest maximum valve opening may be opened first, and then the other automatic valves may be opened.

  In the present embodiment, a safety valve can be provided in the pressure accumulation tank. Then, the set pressure of the safety valve is set lower than the service pressure of the heat exchanger and the loop flow path. Alternatively, a relief valve is provided in a flow path that connects the pressure accumulation tank and the secondary heat exchanger, and the set pressure of the relief valve is set lower than the pressure of the safety valve. Thereby, it is possible to prevent the pressure in the loop heat pipe heat exchange system from becoming higher than the service pressure.

  In the present embodiment, a plurality of fail-open type automatic valves may be provided in the condensed water return channel and the steam channel. And the instrumentation control power supply which is a drive power supply of each automatic valve may be connected to a some power distribution system. Thereby, the control system of the automatic valve can be made redundant, and even when a failure occurs in one distribution system, another automatic valve can be driven from the instrumentation control power source connected to the other distribution system.

  This embodiment can also be applied to a geothermal binary power generation system. In Non-Patent Document 3, a pump is used to transport condensed water, but the loop heat pipe heat exchange system of the present embodiment uses natural circulation due to density difference and gravity.

  According to the present embodiment, in the loop heat pipe heat exchange system, before the operation is started (before the system is started), the heat transfer tube (first heat transfer tube) of the primary side heat exchanger and the heat transfer tube of the secondary side heat exchanger. By filling all of the loop flow path including the (second heat transfer tube) with cooling water, the non-condensable gas can be excluded from the loop flow path.

  After the operation is started (after the heat exchange system is started), steam is generated by heating the cooling water in the primary side heat exchanger. The cooling water pushed out by the steam flows into the pressure accumulation tank, so that the cooling water in the loop flow path can maintain a gas-liquid two-phase flow state. The gas phase portion of the accumulator tank is compressed and maintained in a pressurized state.

  The non-condensable gas is excluded from the loop flow path by the above operation. Thereby, according to this embodiment, the fall of the condensation heat transfer rate in a secondary side heat exchanger can be prevented, and a high heat transfer rate can be obtained compared with the past. Moreover, according to this embodiment, since the pressure increase of the secondary side heat exchanger due to the contribution of the non-condensable gas partial pressure can be prevented, the circulation flow rate of the steam and the cooling water does not decrease. Thereby, in this embodiment, the fall of the heat transfer amount can be prevented.

  If a relief valve is provided in the flow path to the accumulator tank, an orifice is provided in the loop flow path, or a flow path with a large pressure loss is provided in parallel with the condensed water return flow path, the cooling water It is possible to suppress instability of heat flow that can occur when shifting from a single-phase natural circulation heat transfer state circulating through the loop flow path to a boiling / condensation heat transfer state.

  Further, when a check valve is provided between the loop flow path and the pressure accumulation tank, it is possible to prevent the cooling water from flowing backward from the pressure accumulation tank to the loop flow path when the pressure of the loop flow path is reduced. Thereby, generation | occurrence | production of the heat flow instability in heat exchange can be prevented. By suppressing the heat flow from becoming unstable, it is possible to prevent the life and reliability of various devices such as an automatic valve (isolation valve) from deteriorating.

  When this embodiment is applied to a nuclear reactor system as a heat utilization system, the decay heat generated in the core when the reactor is shut down, etc., by natural circulation using density difference and gravity, the atmosphere outside the containment vessel, seawater, Heat can be efficiently radiated to heat sinks such as river water and lake water. Thereby, according to this embodiment, the heat removal performance is improved, and the safety of the nuclear reactor is further improved. In addition, since the fail-open type automatic valve is used in this embodiment, even if the instrumentation control power source is lost, the loop heat pipe heat exchange system can be automatically activated, and the operator manually operates the isolation valve. There is no need to operate or the controller to control the isolation valve. For this reason, the safety of the reactor system can be further improved by adding the loop heat pipe heat exchange system of the present embodiment to, for example, the residual heat removal system of the reactor system.

  In addition, when the loop heat pipe heat exchange system of the present embodiment is applied to a geothermal binary power generation system, it is possible to prevent the condensation performance from being deteriorated by the secondary side heat exchanger. Energy recovery efficiency increases. Thereby, according to the present embodiment, the power generation efficiency is increased and the economic efficiency is improved.

  A first embodiment will be described with reference to FIGS. 1 and 2 are overall schematic configuration diagrams of a loop heat pipe heat exchange system representing basic elements of the present embodiment. In the figure, the valve in the closed state is expressed in black, and the valve in the opened state is expressed in white. Hereinafter, the loop heat pipe heat exchange system may be abbreviated as a heat exchange system.

  As will be described later, the loop heat pipe heat exchange system includes a primary side heat exchanger 21 as a “first heat exchanger”, a secondary side heat exchanger 22 as a “second heat exchanger”, and “ A flow path 6 as a "first flow path", a flow path 7 as a "second flow path", a flow path 16 as a "third flow path", and an isolation valve 8 as a "first isolation valve" , An isolation valve 9 as a “second isolation valve”, and a pressure accumulating tank 17. The primary side heat exchanger 21 has the heat transfer tube 1 as a “first heat transfer tube”, and the secondary side heat exchanger 22 has a heat transfer tube 11 as a “second heat transfer tube”.

  The primary side heat exchanger 21 is disposed in the heating source 23. The primary heat exchanger 21 includes a lower header 2, an upper header 3, and a heat transfer tube 1 provided to communicate with the lower header 2 and the upper header 3, respectively.

  The secondary heat exchanger 22 is disposed in the cooling source 24 at a position higher than the primary heat exchanger 21. That is, the secondary heat exchanger 22 is provided at a position higher than the altitude of the primary heat exchanger 21. This is because the coolant is naturally circulated between the primary heat exchanger 21 and the secondary heat exchanger 22 due to the density difference of the coolant (cooling water and steam) and gravity. It is sufficient that there is a difference in installation position to such an extent that this natural circulation can be realized. Similarly to the primary side heat exchanger 21, the secondary side heat exchanger 22 also includes the lower header 12, the upper header 13, and the heat transfer tubes 11 provided to communicate with the lower header 12 and the upper header 13, respectively. .

  The primary side heat exchanger 21 and the secondary side heat exchanger 22 are connected in communication by flow paths 6 and 7. Here, “connected and connected” means that fluid such as cooling water or steam is movably connected. However, the state where fluid is movably connected is not always expressed as “connected in communication”. In order to realize a clear and simple expression, it may be simply referred to as “connection”.

  In addition, a flow path is a path | route through which a fluid flows, and is implement | achieved by piping, a hose, etc. Therefore, the flow path described below can also be called “piping”, for example.

  The connection between the primary side heat exchanger 21 and the secondary side heat exchanger 22 will be described in detail. The upper header 3 of the primary side heat exchanger 21 and the upper header 13 of the secondary side heat exchanger 22 communicate with each other via a flow path 6 having a valve 8.

  The lower header 12 of the secondary heat exchanger 22 and the lower header 2 of the primary heat exchanger 21 communicate with each other via a flow path 7 having a valve 9. Hereinafter, primary side heat exchanger 21 (lower header 2, heat transfer tube 1, upper header 3), flow path 6, secondary side heat exchanger 22 (upper header 13, heat transfer pipe 11, lower header 12), flow path 7 A flow path constituted by is called a loop flow path.

  Here, the time of starting the heat exchange system is a state in which heat is transported from the primary side heat exchanger 21 to the secondary side heat exchanger 22 by naturally circulating cooling water in the loop flow path. In the following description, the activation of the heat exchange system may be expressed as “operation of the heat exchange system”.

  When both the valve 8 and the valve 9 are opened, the loop flow path is opened. Thereby, the cooling water in the heat transfer tube 1 takes heat of the heating source 23 and changes into steam, and this steam flows into the heat transfer tube 11 through the valve 8 and the flow path 6. The steam is cooled and condensed by the cooling source 24, and heat is transferred to the cooling source 24. Condensed water generated by the condensation of the steam returns to the heat transfer tube 1 by moving down the flow path 7 due to gravity due to the height difference between the primary side heat exchanger 21 and the secondary side heat exchanger 22. This circulation loop is applied to the case where the heat source 23 is removed to dissipate heat to the ambient environment temperature cooling source 24, and conversely, when the ambient environment temperature heating source 23 is cooled by the cooling source 24 cold. it can.

  The pressure accumulation tank 17 is attached to the flow path 6 via the flow path 16. The pressure-accumulating tank 17 that can be sealed has a gas phase portion 17a that stores steam and gas, and a liquid phase portion 17b that stores cooling water. The bottom of the pressure accumulating tank 17 is located downstream of the heat transfer tube 11 of the secondary heat exchanger 22 and communicates with the flow path 7 through the flow path 16.

  The location (connection point) where the flow path 16 communicates and is connected downstream of the heat transfer tube 11 means below the condensed water level in the heat transfer tube 11 during normal operation of the heat exchange system. In FIG. 1, the flow path 16 communicates with and is connected to the lower header 12.

  A flow path 19 having a valve 18 is connected to the upper part of the pressure accumulation tank 17. A gas vent channel 5 having a valve 4 is connected to the upper header 3 of the primary side heat exchanger 21. Another degassing flow path 15 having a valve 14 is connected to the upper header 13 of the secondary heat exchanger 22.

  Here, the connection point between the pressure accumulation tank 17 and the loop flow path is not limited to the example shown in FIG. For example, as shown in the modification of FIG. 2, the flow path 16 may be connected in communication at the height position of the lower header 2 of the primary side heat exchanger 21. The connection point of the flow path 16 and the loop flow path (for example, the flow path 7) may be anywhere below the condensed water level of the secondary heat exchanger 22, and is not limited to the lower header 12.

  The operation procedure of the heat exchange system and the operation during normal operation will be described with reference to FIGS. FIG. 3 shows a procedure (water filling procedure) for filling the heat exchange system with cooling water.

  Before starting operation, the valve 18, the valve 4, and the valve 14 are opened. And the cooling water W1 is inject | poured from the inflow port of the flow path 19. FIG. The cooling water flows through the pressure accumulating tank 17 and the flow path 16 into the loop flow path connecting the primary side heat exchanger 21 and the secondary side heat exchanger 22 to fill the loop flow path. At this time, the gas phase containing the non-condensable gas in the loop flow path is pushed up by the liquid surface and discharged to the outside from the gas vent flow path 5 and the gas vent flow path 15. As a result, the loop flow path is substantially entirely filled with cooling water. When the gas phase containing the non-condensable gas is discharged, the valve 4 and the valve 14 are sequentially closed, and finally the valve 18 is closed to finish water injection (liquid injection).

  FIG. 4 shows a state at the start of operation (starting up) of the heat exchange system. When the valves 8 and 9 are opened, the heat exchange system is activated. In other words, the operation of the heat exchange system can be controlled only by opening and closing the valves 8 and 9.

  For example, when the heat exchange system is used as an emergency system for heat dissipation at the time of an accident or stop, the valves 8 and 9 may be closed until the operation is started. When an emergency occurs, the operation of the heat exchange system can be started by opening the valves 8 and 9. As shown in the examples described later, the valves 8 and 9 may be configured as fail-open type automatic valves. In this case, when the power supply for operating the valves 8 and 9 is stopped, the valves 8 and 9 are automatically opened, so that the loop heat pipe heat exchange system automatically starts operation.

  When the heat exchange system starts operation, the cooling water in the heat transfer tube 1 is heated by the heat of the heating source 23, and the liquid temperature rises. Since the density of the cooling water decreases due to the temperature rise, buoyancy is generated in the cooling water in the heat transfer tube 1. Thereby, in the loop flow path, the flow of the high-temperature water W2 that goes up the flow path 6 toward the secondary side heat exchanger 22 and the low-temperature water that goes down the flow path 7 and returns to the primary side heat exchanger 21 W3 flows. The flow of the high temperature water W2 and the flow of the low temperature water W3 causes natural circulation in the loop flow path.

  Until the cooling water in the heat transfer tube 1 is continuously heated by the heating source 23 and boiling occurs in the heat transfer tube 1, the liquid level in the pressure accumulation tank 17 is almost the same as that before the start of operation shown in FIG. equal. Next, the state after boiling will be described.

  FIG. 5 shows a state in which a part of the cooling water has boiled. The inside of the heat transfer tube 1 and the flow path 6 is filled with the generated steam. Since the volume of the loop flow path expands due to the generated steam, a part of the cooling water flows from the loop flow path to the pressure accumulation tank 17 through the flow path 16.

  On the other hand, the steam flowing into the heat transfer tube 11 from the flow path 6 is cooled and condensed by the cooling source 24 and returns to the cooling water.

  By the way, when the cooling water pushed out by the volume expansion of the loop flow channel flows into the pressure accumulation tank 17, the water level of the liquid phase 17b in the pressure accumulation tank 17 rises and the gas phase 17a is compressed. Thereby, both the pressure in the pressure accumulation tank 17 and the pressure in the loop flow path increase. When the pressure in the loop flow path increases, the internal steam of the heat transfer tube 1, the flow path 6 and the heat transfer tube 11 decreases in volume and balances with the volume expansion due to vaporization. As a result, a steam / liquid ratio circulation balanced with the pressure in the pressure accumulating tank 17 is formed.

  Preferably, from the temperature of the heating source 23 and the temperature of the cooling source 24, the relationship between the steam / liquid ratio and the pressure in the pressure accumulating tank 17 is obtained by heat transfer calculation. If the initial liquid level in the pressure accumulation tank 17 is set so that the upper part in the heat transfer tube 11 is occupied by steam and the lower part in the heat transfer tube 11 is occupied by condensate (cooling water), the loop heat pipe heat The thermal efficiency of the exchange system is improved. It may be adjusted by opening and closing the valve 18 after the start of operation so that the upper part in the heat transfer tube 11 is occupied by steam and the lower part of the heat transfer tube 11 by condensate, and the gas in the gas phase 17a is extracted.

  In this embodiment, as shown in FIG. 3, since the loop flow path is filled with cooling water before the operation is started to eliminate the gas phase, no non-condensable gas remains in the loop flow path. This prevents a decrease in condensation heat transfer coefficient in the secondary side heat exchanger. Furthermore, since the increase in the pressure of the secondary heat exchanger due to the contribution of the non-condensable gas partial pressure can be suppressed, the circulation flow rate of the steam and the cooling water does not decrease, and the heat transfer rate can be prevented from decreasing. Further, since it is not necessary to control the mechanism for discharging the non-condensable gas, the apparatus can be simplified and the reliability of the system is improved.

  FIG. 6 shows a schematic configuration of a loop heat pipe heat exchange system according to another modification of the first embodiment. The configuration of FIG. 6 is different from the configuration of FIG. 1 in that a check valve 20 is provided in the flow path 16. The check valve 20 permits a flow from the flow path 7 to the pressure accumulation tank 17 via the flow path 16 and blocks a flow from the pressure accumulation tank 17 to the flow path 7 via the flow path 16.

  When the check valve 20 is not provided, when the heat load of the heating source 23 is reduced in the primary heat exchanger 21 during operation of the heat exchange system, the cooling water flows backward from the pressure accumulation tank 17 to the loop flow path. Thereby, the volume ratio of the vapor | steam in a loop flow path reduces, and the inside of the heat exchanger tube 1 may be satisfy | filled with a liquid phase. However, heat transfer by natural convection of single-phase flow is lower than boiling heat transfer, which reduces the amount of heat transport in the heat exchange system. When the heat transport amount decreases, the heat removal amount of the heating source 23 decreases and the heat load increases. When the heat load of the heating source 23 increases, as described above, the flow toward the pressure accumulating tank 17 occurs again due to the volume expansion of the loop flow path. Thus, the flow of the cooling water and the fluctuation of the heat load (hereinafter referred to as unstable heat flow) are repeated.

  Therefore, as shown in FIG. 6, if a check valve 20 is provided in the middle of the flow path 16, the amount of liquid in the pressure accumulating tank 17 at the maximum heat load can be maintained, so that heat flow instability can be prevented.

  According to the present embodiment (and a plurality of modifications) described in FIGS. 1 to 6, it is possible to prevent the heat transfer performance from being lowered and to simplify the configuration of the loop heat pipe heat exchange system. In addition, since the check valve 20 can suppress the instability of heat flow, it can prevent the valve and the flow path from being damaged due to vibrations, etc., and the maintainability, reliability and economy of the loop heat pipe heat exchange system can be reduced. It can be improved.

  A second embodiment will be described with reference to FIG. In the following embodiments including the present embodiment, differences from the first embodiment will be mainly described.

  In this embodiment, the loop heat pipe heat exchange system is applied to a heat utilization system that extracts power and generates power by a steam energy conversion device such as a steam turbine. This embodiment can be combined with any of the first embodiment and a plurality of modifications thereof.

  Here, a geothermal binary power generation system is taken as an example of the heat utilization system. The geothermal binary power generation system has a circulation loop in which a steam turbine is rotated by low-boiling-point cooling water that exchanges geothermal heat.

  In the loop heat pipe heat exchange system shown in FIG. 7, the steam energy conversion device 25, the bypass flow path 44, and the like are provided in the flow path 6 as compared with the configuration shown in FIG. 1. Specifically, a steam energy conversion device 25 is provided in the middle of the flow path 6. A bypass channel 44 is provided in the middle of the channel 6 so as to bypass the steam energy conversion device 25. A reference numeral 45 is given to a flow path in the range bypassed by the bypass flow path 44 in the flow path 6.

  A valve 42 is provided upstream of the steam energy conversion device 25, and a valve 43 is provided downstream of the steam energy conversion device 25. Further, a gas vent channel 47 having a valve 46 is connected downstream of the steam energy conversion device 25 and located upstream of the valve 43. Although not shown, when the cooling water used in the loop flow path cannot be discarded directly into the atmosphere, an appropriate exhaust treatment apparatus or waste liquid treatment apparatus is connected downstream of the gas vent flow path 47.

  A valve 41 is provided in the bypass channel 44. The upstream side of the bypass channel 44 is connected to and connected to the channel 6 on the upstream side of the valve 42. The downstream side of the bypass channel 44 is connected to and connected to the channel 6 on the downstream side of the valve 43. Therefore, when the valve 41 is opened with the valves 42 and 43 closed, all of the cooling water (or steam) from the primary side heat exchanger 21 flows through the bypass flow path 44, and the secondary side heat exchanger. Head to 22.

  Before starting the operation of the heat exchange system, the valve 41 is opened and the valves 42 and 43 are closed to isolate the steam energy conversion device 25 from the heat exchange system. The procedure for discharging the gas phase containing the non-condensable gas from the heat exchange system, the procedure for forming the circulation of the vapor / liquid ratio balanced with the pressure in the pressure accumulating tank 17, and the actions related to these procedures are as follows. As described in the examples.

  After discharging the non-condensable gas from the loop flow path and forming a circulation with the desired vapor / liquid ratio in the loop flow path, the valve 47 is opened, the valve 42 is opened slightly, and at the same time the valve 41 is turned slightly squeeze. Thus, the steam G3 from the primary heat exchanger 21 is introduced into the steam energy conversion device 25. By the introduced steam G <b> 3, the non-condensable gas inside the steam energy conversion device 25 is discharged from the gas vent channel 47.

  When the non-condensable gas is discharged from the gas vent passage 47 and then the steam is discharged, the opening operation of the valve 42 and the valve 43 and the closing operation of the valve 47 and the valve 41 are started. The valve operation is continued until the valve 43 is fully opened and the valve 47 and the valve 41 are fully closed.

  As a result, the loop heat pipe heat exchange system can be operated with all the non-condensable gas discharged from the loop flow path. The steam from the heat transfer tube 1 of the primary side heat exchanger 21 flows into the steam energy conversion device 25 and rotates the steam turbine or the like. The steam that has finished work flows from the flow path 6 to the heat transfer tube 11 and is condensed.

  According to this embodiment, the same effects as those of the first embodiment can be obtained. That is, in this embodiment, since there is almost no non-condensable gas in the steam, it is possible to prevent the heat transfer rate of the condensation heat from decreasing. Furthermore, since the pressure increase in the secondary heat exchanger 22 due to the contribution of the non-condensable gas partial pressure can be suppressed, the amount of steam flowing through the steam turbine does not decrease. Therefore, in this embodiment, it is possible to suppress a decrease in operating efficiency such as power generation efficiency, and the steam energy conversion device 25 can be operated efficiently. Furthermore, since it is not necessary to automatically control a mechanism for discharging non-condensable gas, the configuration of the heat exchange system can be simplified, and reliability and maintainability are improved.

  The third embodiment will be described in detail with reference to FIGS. FIG. 8 shows a case where the loop heat pipe heat exchange system is applied to a heat dissipation system at the time of an accident or stop of the heat utilization system. This embodiment can be combined with any of the first embodiment and a plurality of modifications thereof. Here, a case where the loop heat pipe heat exchange system shown in FIG. 6 is used for a heat dissipation system will be described as an example. The illustration of the heat utilization system is omitted.

  In this embodiment, a valve 28 is provided in the flow path 6 and a valve 29 is provided in the flow path 7. These valves 28 and 29 are configured as automatic valves that can be operated remotely, for example, driven by an electric motor, a pneumatic actuator, or the like. These automatic valves 28 and 29 are configured as fail-open valves that are opened when the driving force for operating the valves is lost due to the loss of power supply or pipe breakage.

  In the present embodiment, the check valve 20 is provided for the description based on the configuration of FIG. 6, but the present invention can also be applied to a configuration without the check valve 20.

  Before starting the operation of the heat exchange system of the present embodiment, the procedure for discharging the gas phase containing the non-condensable gas is as described in the first embodiment. In this embodiment, the heat exchange system is installed in a place where the heat source of the heat utilization system can be cooled. As described in the first embodiment, the secondary heat exchanger 22 is a place where cooling is possible and is positioned higher than the primary heat exchanger 21.

  During normal operation of the heat utilization system, the automatic valve 28 and the automatic valve 29 are closed so that the efficiency of the heat utilization system does not decrease, and the heat exchange system is disconnected from the heat utilization system. That is, by closing both the automatic valves 28 and 29, heat transport from the heat transfer tube 1 to the heat transfer tube 11 and heat dissipation to the cooling source 24 are prevented.

  On the other hand, when a failure or the like occurs in the heat utilization system and the heating source 23 needs to be cooled, the automatic valve 28 and the automatic valve 29 are opened as shown in FIG. Start driving. FIG. 9 shows the situation at the start of operation.

  Here, as described above, since the automatic valves 28 and 29 are both configured as fail-open type automatic valves, the control device that controls the automatic valves 28 and 29 stops due to, for example, power loss, Even when the drive source of the actuator of the automatic valves 28 and 29 is stopped, the valve is automatically opened as the reference position.

  When the automatic valves 28 and 29 are opened, a loop flow path between the primary side heat exchanger 21 and the secondary side heat exchanger 22 is formed. The cooling water W <b> 2 heated by the heat transfer tube 1 flows to the heat transfer tube 11 through the automatic valve 28 and the flow path 6. The cooling water W3 cooled by the heat transfer tube 11 of the secondary side heat exchanger 22 returns to the heat transfer tube 1 through the flow path 7 and the automatic valve 29.

  FIG. 10 shows a state after starting operation of the loop heat pipe heat exchange system. The steam G3 generated by being heated in the heat transfer tube 1 of the primary side heat exchanger 21 flows into the heat transfer tube 11 of the secondary side heat exchanger 22 through the automatic valve 28 and the flow path 6. The steam is cooled and condensed in the heat transfer tube 11 of the secondary side heat exchanger 22. The cooling water W4 from the heat transfer tube 11 returns to the heat transfer tube 1 of the primary heat exchanger 21 via the flow path 7 and the automatic valve 29.

  FIG. 11 is a schematic configuration diagram of a loop heat pipe heat exchange system according to a modification of the third embodiment. In this modification, the automatic valve 28 is omitted as compared with the configuration of FIG. Therefore, in this modification, since the heat utilization system and the heat exchange system cannot be completely separated, after the operation of the heat utilization system is started, a heat source is provided inside the heat transfer tube 1 and part of the flow path 6. The steam heated by 23 stays. When the heat of the vapor stored in the flow path 6 and the like is radiated into the atmosphere, the heat radiation becomes a heat loss for the heat utilization system.

  However, according to this modification, the operation of the loop heat pipe heat exchange system can be started only by opening one automatic valve 29. Therefore, in the heat dissipation system including the heat exchange system according to this modification, the possibility that the automatic valve breaks down is lower than that in each of the above embodiments, and the reliability is improved. Furthermore, since only one automatic valve 29 is provided, the maintenance work is easier than in the above embodiments.

  According to the present embodiment described above, the same effects as those of the first embodiment can be achieved when applied to a heat dissipation system at the time of an accident or stop of the heat utilization system. Furthermore, since instability during heat exchange can be prevented, the safety and reliability of a heat utilization system using a loop heat pipe heat exchange system is improved.

  A fourth embodiment will be described with reference to FIGS. This embodiment can be applied to, for example, the third embodiment and its modifications. Furthermore, the present embodiment can be applied to any of the first embodiment, a plurality of modifications thereof, and the second embodiment.

  When the loop heat pipe heat exchange system is applied to a heat dissipation system that responds to an accident or stop of the heat utilization system, the automatic valves 28 and 29 are closed as described in the third embodiment, so that the heat exchange system is closed. Can be separated from the heat utilization system.

  In this case, since no flow is generated in the loop flow path of the heat exchange system during operation of the heat utilization system, heat loss is small.

  By the way, since the cooling water in the heat transfer tube 1 is heated by the heating source 23 during the operation of the heat utilization system, the cooling water in the heat transfer tube 1 is in a high temperature and high pressure state. On the other hand, since a part of the heat transfer tube 11 and the cooling water in the flow path 6 and the flow path 7 communicate with the pressure accumulation tank 17 through the flow path 16, the pressure of the loop flow path is equal to the pressure of the pressure accumulation tank 17. Relied on and kept at a relatively low pressure.

  Here, when the automatic valve 28 and the automatic valve 29 are opened to start the operation of the heat exchange system in order to cope with a failure of the heat exchange system, the temperature of the cooling water in the heat transfer tube 1 is changed to the flow paths 6 and 7. It is assumed that the temperature is higher than the saturation temperature corresponding to each internal pressure of the heat transfer tube 11. In this case, the rapid circulation of the boiling under reduced pressure and the cooling water occurs in the loop flow path without going through the heating process of the cooling water single phase described in FIG. 4 and FIG.

  At this time, the cooling water in the flow path 7 is at a low temperature and is in a high subcooled state. Therefore, the steam is condensed in the heat transfer tube 1 immediately after the circulation, and there is a possibility that thermal flow instability such as a flow instability phenomenon or a water hammer phenomenon due to repeated evaporation and condensation may occur.

  In this embodiment, an orifice 30 is provided in the middle of the flow path 7 in order to reduce the occurrence of an unstable flow. Since the pressure loss occurs when the cooling water passes through the orifice 30, the head pressure of the condensed water flowing from the heat transfer tube 11 is reduced, and the flow rate of the cooling water is reduced. Accordingly, excessive cooling in the heat transfer tube 1 due to rapid circulation can be prevented, so that an unstable flow phenomenon and a water hammer phenomenon due to repeated evaporation and condensation can be suppressed. The present embodiment can also be applied to a configuration including the check valve 20.

  FIG. 13 is a schematic configuration diagram of a loop heat pipe heat exchange system according to a modification of the present embodiment. In this modification, in the heat exchange system shown in FIG. 12, a bypass flow path 36 is provided in the middle of the flow path 7 so as to bypass the automatic valve 29, and the automatic valve 35 is arranged in the bypass flow path 36. These automatic valves 29 and 35 correspond to “a plurality of second isolation valves having different flow path areas”.

  The bypass channel 36 has a smaller channel area than the channel 7. The automatic valve 35 provided in the bypass channel 36 also has a smaller maximum channel area than the automatic valve 28. In this modified example, when the heat utilization system is in an accident or stopped, first, the automatic valve 35 is opened to flow a comparatively small flow rate of cooling water to prevent excessive cooling in the heat transfer tube 1. Thereafter, the automatic valve 29 is opened, and the operation is shifted to a steady operation. Thereby, the unstable phenomenon of the flow and the water hammer phenomenon can be suppressed. Note that after the automatic valve 29 is opened, the automatic valve 35 may be closed or may remain open.

  According to the present embodiment described above, the same operational effects as in the third embodiment can be obtained. That is, since the heat flow instability can be suppressed in application to a heat dissipation system at the time of an accident or stop of the heat utilization system, the safety and reliability of the heat utilization system using the loop heat pipe heat exchange system is improved.

  A fifth embodiment will be described with reference to FIGS. FIG. 14 is a schematic configuration diagram of a loop heat pipe heat exchange system according to the present embodiment. In this embodiment, with respect to the heat exchange system shown in the third embodiment, it is possible to suppress the occurrence of repetition of evaporation and condensation due to the rapid circulation of the low-temperature cooling water at the time of startup through the loop flow path.

  In this embodiment, a relief valve 33 and a valve 32 are provided in the middle of the flow path 16, and a bypass flow path 37 is provided in parallel with the flow path 16 so as to bypass the relief valve 33 and the valve 32. Yes. Of these components 31, 32, 33, and 37, the minimum required component in the present embodiment is a relief valve 33. The bypass flow path 37, the valve 31, and the valve 32 are components for maintenance and detour operation. In FIG. 14, the check valve 20 is provided in the flow path 16, but the present embodiment can also be applied to a configuration without the check valve 20.

  The procedure for filling the loop flow path with the cooling water before starting the operation and removing the gas phase containing the non-condensable gas is the same as the procedure described in the first embodiment, and is omitted here. When the relief valve 33 is not provided, the set pressure of the relief valve 33 is such that cooling water corresponding to the internal volume of the heat transfer pipe 1, the flow path 6, and the heat transfer pipe 11 flows into the pressure accumulating tank 17 and the gas phase 17a is generated. This is an intermediate pressure between the pressure generated when the pressure is compressed to the maximum and the loop flow path pressure when the cooling water is filled in the loop flow path before the start of operation.

  Until the operation of the heat exchange system is started, since the automatic valve 28 and the automatic valve 29 are closed, the heat utilization system and the heat transfer tube 1 are isolated. Since the heat transfer tube 1 is isolated, no flow occurs in the loop flow path, so that heat loss is small. However, since the cooling water in the heat transfer tube 1 is heated by the heating source 23, the cooling water in the heat transfer tube 1 is in a high temperature and high pressure state.

  At the start of operation of the heat exchange system, the automatic valve 28 and the automatic valve 29 are opened. Thereby, the cooling water circulates through the loop flow path of the heat transfer tube 1, the flow path 6, the heat transfer pipe 11, and the flow path 7. At this time, since the flow from the loop flow path to the pressure accumulation tank 17 is blocked by the relief valve 33, the cooling water circulates in the loop flow path in a substantially single-phase flow state.

  The high-temperature cooling water of the heat transfer tube 1 flows into the heat transfer tube 11 via the heat transfer tube 1 and the flow path 6 due to buoyancy due to the density difference, and heat is exchanged in the heat transfer tube 11 by natural convection heat transfer. The cooling water whose temperature has decreased due to heat exchange returns from the flow path 7 to the heat transfer tube 1 due to the gravity caused by the height difference between the installation locations of the primary side heat exchanger 21 and the secondary side heat exchanger 22.

  The cooling water recirculated to the heat transfer tube 1 is heated while flowing through the heat transfer tube 1 and the temperature rises. When the cooling water temperature reaches the vicinity of the saturation temperature, the pressure in the loop flow path of the heat transfer pipe 1, the flow path 6, the heat transfer pipe 11, and the flow path 7 increases.

  When the pressure in the loop flow path exceeds the set pressure of the relief valve 33, the relief valve 33 is opened, a part of the cooling water flows into the pressure accumulating tank 17, and boiling is activated. By the time the relief valve 33 is opened, the temperature of the cooling water in the loop flow path has risen, and the subcooling degree of the cooling water flowing into the heat transfer tube 1 becomes low. Therefore, the unstable flow phenomenon and the water hammer phenomenon due to repeated evaporation and condensation in the heat transfer tube 1 can be suppressed.

  FIG. 15 is a schematic configuration diagram of a loop heat pipe heat exchange system according to a modification of the present embodiment. In this modification, in the heat exchange system shown in FIG. 14, a safety valve 34 that communicates with the gas phase 17 a is provided above the pressure accumulation tank 17.

  The set pressure of the safety valve 34 is set higher than the set pressure of the relief valve 33 and lower than the pressure resistance of the heat exchangers 21 and 22 and the flow paths 6 and 7 constituting the heat exchange system. Although not shown, when the cooling water used in the loop flow path cannot be discarded directly into the atmosphere, an appropriate gas-liquid treatment device may be connected downstream of the safety valve 34 outlet.

  In the heat exchange system shown in FIG. 14, when the pressure in the loop flow path rises after the operation is started and the relief valve 33 is opened and a part of the cooling water moves to the pressure accumulation tank 17, boiling in the heat transfer tube 1 is activated. To do.

  Further, as a result of excessive heating from the heating source 23, when the pressure in the loop flow path approaches the pressure resistance of the loop flow path or the pressure accumulating tank 17, the safety valve 34 opens. Thereby, the pressure of a loop flow path falls and the damage of an apparatus is prevented. Although a part of the cooling water becomes steam and is discharged from the safety valve 34, the operation of the heat exchange system can be continued below the pressure resistance until the cooling water stored in the pressure accumulating tank 17 disappears. The fifth embodiment and the present modification can also be applied to a configuration that does not include the check valve 20.

  According to the present embodiment described above, the same operational effects as in the third embodiment can be obtained. Furthermore, in this embodiment, since the pressure accumulation tank 17 is provided with the safety valve 34, the operation of the heat exchange system can be continued below the pressure resistance of the loop flow path and the pressure accumulation tank 17 even during overheating. It can prevent equipment such as piping from being damaged. As a result, in this embodiment, safety and reliability are further improved.

  A sixth embodiment will be described with reference to FIG. FIG. 16 is a longitudinal sectional view showing an example in which the loop heat pipe heat exchange system according to this embodiment is applied to a reactor cooling system. FIG. 16 illustrates a boiling water reactor, but the present invention can be applied to other types of reactors such as light water reactors such as pressurized water reactors, fast breeder reactors, new conversion reactors, and high-temperature gas reactors. It is.

  As shown in FIG. 16, the nuclear reactor 50 includes, for example, a pressure vessel 52, a containment vessel 51, and a reactor building (not shown) that houses the containment vessel 51. The pressure vessel 52 contains a core 53 loaded with nuclear fuel. The pressure vessel 52 is installed in the containment vessel 51.

  High-temperature and high-pressure steam generated in the core 53 in the pressure vessel 52 is taken out through the main steam pipe 54. The feed water corresponding to the amount of generated steam is supplied into the pressure vessel 52 from a feed pipe (not shown). A main steam isolation valve 55 is provided in the main steam pipe 54 so that the pressure vessel 52 can be isolated when the nuclear reactor 50 is stopped or in an accident.

  In the storage container 51, for example, a pressure suppression pool 62, a storage container cavity 61, a dry well 65, and the like are provided. In the pressure suppression pool 62, the vapor discharged into the storage container 51 at the time of an accident such as when the main steam pipe 54 is broken is led from the vent pipe 66 to condense, so that the inside of the storage container 51 is in an overpressure state. To prevent. The upper space in the pressure suppression pool 62 is a wet well gas phase space 63. The storage container cavity 61 is a lower space of the pressure container 52. The dry well 65 is a gas phase space of the storage container 51.

  Further, a residual heat removal system (not shown) is provided outside the containment vessel 51 to cool the core 53 at the time of stoppage or accident, release the heat to the outside, and supply cooling water using a pump.

  In the present embodiment, the primary heat exchanger 21 is disposed in the storage container 51. The primary heat exchanger 21 is surrounded by a heat exchanger barrel 72 as a “casing”. The upper part of the heat exchanger barrel 72 is connected to the main steam pipe 54 through a main steam extraction pipe 64 as an “introduction channel”. The inlet side of the main steam extraction pipe 64 is located upstream of the main steam isolation valve 55 and is connected to the main steam pipe 54. The heat exchanger barrel 72 condenses the steam introduced from the main steam extraction pipe 64 in the heat transfer pipe 1 of the primary side heat exchanger 21.

  The lower space of the heat exchanger barrel 72 can communicate with different spaces via the flow paths 58, 60, 59, and the condensed water stored in the heat exchanger barrel 72 is set in advance. It can be released into the space.

  That is, the lower space of the heat exchanger barrel 72 can communicate with the pressure vessel 52 via the pressure vessel water injection channel 58 having the automatic valve 67. Further, the lower space of the heat exchanger barrel 72 can communicate under the water surface of the pressure suppression pool 62 via a wet well water injection channel 60 having an automatic valve 69. Further, the lower space of the heat exchanger barrel 72 can communicate with the storage container cavity 61 through a storage container cavity water injection channel 59 having an automatic valve 68.

  Here, the pressure vessel injection channel 58 is the “pressure vessel side return channel”, the storage vessel cavity injection channel 59 is the “container cavity side return channel”, and the wet well injection channel 60 is the “wet well side”. It corresponds to “return channel”. The automatic valve 67 corresponds to a “pressure vessel side isolation valve”, the automatic valve 68 corresponds to a “container cavity side isolation valve”, and the automatic valve 69 corresponds to a “wet well side isolation valve”.

  A configuration example of the automatic valves 57, 67, 68 will be described. Preferably, the automatic valve 57 is configured as a fail-open type automatic valve, and any one of the automatic valve 67, the automatic valve 68, and the automatic valve 69 is configured as a fail-open type automatic valve. Here, the automatic valve represents, for example, a valve that can be remotely operated by power such as an electric motor, a gas cylinder, a hydraulic cylinder, a hydraulic motor, and an air motor. A fail-open type automatic valve represents a valve whose return position is open when the supply of power is cut off.

  As shown in FIG. 14 and the like, the primary heat exchanger 21 as the “first heat exchanger” includes the heat transfer tube 1 as the “first heat transfer tube”, the lower header 2 and the upper portion where the heat transfer tube 1 communicates. And a header 3.

  In the external space of the storage container 51, a secondary heat exchanger 22 as a “second heat exchanger” is provided. As shown in FIG. 14 and the like, the secondary heat exchanger 22 includes a heat transfer tube 11 as a “second heat transfer tube”, and a lower header 12 and an upper header 13 with which the heat transfer tube 11 communicates.

  The secondary side heat exchanger 22 is installed outside the containment vessel 51 at an altitude higher than the installation height of the primary side heat exchanger 21. The secondary side heat exchanger 22 is cooled by an air cooling method. In order to enhance the air cooling effect, the secondary heat exchanger 22 is provided in the duct 70. The cooling air G5 flows from the inlet 71b of the duct 70 toward the outlet 71a. Thereby, the heat exchanger tube 11 of the secondary side heat exchanger 22 is air-cooled.

  The upper header 3 of the primary side heat exchanger 21 and the upper header 13 of the secondary side heat exchanger 22 are connected in communication by a flow path 6 having an automatic valve 28. The lower header 12 of the secondary side heat exchanger 22 and the lower header 2 of the primary side heat exchanger 21 are connected in communication by a flow path having an automatic valve 29. Here, the flow path 6 corresponds to a “first flow path”, and the flow path 7 corresponds to a “second flow path”.

  In the middle of the flow path 7, a pressure accumulation tank 17 is provided via the flow path 16. For example, the pressure accumulation tank 17 is connected in communication with the lower header 12 through the flow path 16 including the relief valve 33 and the check valve 20.

  The operation of the reactor loop heat pipe heat exchange system will be described. When the residual heat removal system cannot be started when the reactor is shut down, the loop heat pipe heat exchange system starts operation as follows to remove the heat of the core 53.

  When the nuclear reactor is operating normally, a loop flow path consisting of the heat transfer tube 1, the upper header 2, the flow path 6, the upper header 12, the heat transfer pipe 11, the lower header 13, the flow path 7, and the lower header 3, The flow path 16 and a part of the pressure accumulating tank 17 are previously filled with cooling water, respectively, and noncondensable gas is removed as much as possible.

  Before starting the operation of the loop heat pipe heat exchange system, the automatic valve 28 and the automatic valve 29 are closed. Further, the automatic valve 57, the automatic valve 55, the automatic valve 67, and the automatic valve 69 are also closed.

  When a failure or accident occurs in the nuclear reactor, after the main steam isolation valve 55 is closed, the automatic valve 57 and the automatic valve 67, and the automatic valve 28 and the automatic valve 29 are opened. Thereby, the steam G4 flowing out from the pressure vessel 52 flows into the heat exchanger barrel 72 through the main steam pipe 54, the automatic valve 57, and the flow path 64. Since the steam G4 flowing into the heat exchanger barrel 72 heats the heat transfer tube 1, the temperature of the cooling water in the heat transfer tube 1 rises.

  As a result, the cooling water in the heat transfer tube 1 and the flow path 6 has a relatively low density at a high temperature. On the other hand, the cooling water in the heat transfer tube 11 and the flow path 7 has a relatively high density at a low temperature. Furthermore, the heat transfer tube 11 of the secondary side heat exchanger 22 is installed at a higher position than the heat transfer tube 1 of the primary side heat exchanger 21. Therefore, the cooling water in the loop flow path starts natural circulation due to the density difference and gravity.

  The high-temperature cooling water that has flowed from the flow path 6 to the upper header 12 is cooled by the air G <b> 5 flowing in the duct 70 in the heat transfer tube 11 of the secondary heat exchanger 22. On the other hand, the vapor | steam G4 which heated the heat exchanger tube 1 is cooled and condensed outside the tube of the heat exchanger tube 1, and becomes condensed water (cooling water) W5. Condensed water W5 is poured into the pressure vessel 52 from the lower part of the heat exchanger barrel 72 through the automatic valve 67 and the pressure vessel pouring channel 58.

  Since the pressure in the pressure vessel 52 immediately after the reactor 50 is shut down is higher than the pressure in the loop flow path of the loop heat pipe heat exchange system, the temperature of the steam emitted from the pressure vessel 52 is the cooling water circulating in the loop flow path. Higher than the saturation temperature. Therefore, if the heat transfer tube 1 continues to be heated by the steam G4 flowing into the heat exchanger barrel 72, the cooling water in the heat transfer tube 1 starts to boil.

  Due to the volume expansion due to the steam generated in the heat transfer tube 1, the pressure of the cooling water in the loop flow path rises. When the pressure in the loop flow path becomes higher than the set pressure of the relief valve 33, the relief valve 33 is opened. Thereby, a part of the cooling water in the loop flow path flows into the pressure accumulation tank 17 through the flow path 16 and the relief valve 33.

  Since the pressure accumulating tank 17 is sealed, the loop flow path is gradually pressurized and finally balanced with a pressure commensurate with the heating amount in the primary side heat exchanger 21. At this time, by adjusting the gas phase volume of the pressure accumulating tank 17 in advance, the heat transfer tube 1, the flow path 6, and the upper portion of the heat transfer tube 11 are respectively filled with steam, and condensed water is formed in the lower portion of the heat transfer tube 11. In the accumulated state, normal operation of the loop heat pipe heat exchange system can be performed.

  As described above, the steam generated in the core 53 is condensed in the heat exchanger body 72 and supplied to the pressure vessel 52, and the heat of the steam is transferred from the primary side heat exchanger 21 to the secondary side heat exchanger 22. And can be removed by air cooling outside the containment vessel 51. During normal operation of the loop heat pipe heat exchange system, since the inside of the loop flow path is filled with cooling water in advance, non-condensable gas that inhibits heat transfer does not exist in the loop flow path. Therefore, it is possible to prevent a decrease in heat transfer performance in the above-described boiling of cooling water and condensation heat transfer.

  In the above-described opening / closing operation of the automatic valve, when the automatic valve 68 is opened instead of the automatic valve 67, the condensed water W5 is injected into the containment vessel cavity 61 through the containment vessel cavity injection flow path 59 to prepare for the melting of the core. Used as cooling water.

  When the automatic valve 69 is opened instead of the automatic valve 67, the condensed water W <b> 5 is injected into the pressure suppression pool 62 through the wet well injection channel 60. Condensed water W5 poured into the pressure suppression pool 62 is steam condensing cooling water for reducing the pressure in the containment vessel 51 or an emergency core cooling system (not shown) for injecting cooling water into the pressure vessel 52. It is used as raw water.

  The water injection destination of the condensed water W5 can be switched or distributed by controlling the open / close state of the automatic valve 67, the automatic valve 68, and the automatic valve 69.

  For example, the operation when the control power of the nuclear reactor is further lost after the accident of loss of all the nuclear power is occurred will be described. When the remote control function of the automatic valve is lost due to the loss of the control power supply, the automatic valve 28, the automatic valve 29, and the automatic valve 57 are opened by the fail open function. As a result, the loop heat pipe heat exchange system automatically starts operation and performs heat removal operation without any external control. Here, when the automatic valve 67 is also a fail-open type automatic valve, the condensed water W5 in the heat exchanger barrel 72 is automatically injected into the pressure vessel 52 through the flow path 58.

  When the automatic valve 68 is a fail-open automatic valve, the condensed water W5 in the heat exchanger barrel 72 is automatically poured into the containment vessel cavity 61 through the flow path 59. When the automatic valve 69 is a fail-open automatic valve, the condensed water W5 in the heat exchanger barrel 72 is automatically poured into the pressure suppression pool 62. The automatic valve 67, the automatic valve 68, and the automatic valve 69 described above are configured so that only one of the valves is a fail-open type valve and the remaining two valves are fail-close type valves in order to prevent backflow of the mutual flow paths. And Here, the fail-close type valve means a valve whose return position is closed when the supply of power is cut off.

  According to the present embodiment described above, the same operational effects as the first embodiment can be obtained. Further, it is possible to prevent the heat removal performance and pressure reduction performance in the core 53 and the containment vessel 51 from being deteriorated in the event of a failure or accident when the reactor is shut down. For this reason, according to the present embodiment, the safety of the nuclear reactor is improved. Moreover, since the core 53 and the containment vessel 51 can be automatically cooled even if the control power is lost, the reliability of the nuclear reactor is improved.

  A seventh embodiment will be described with reference to FIG. FIG. 17 is a longitudinal sectional view showing an example in which the loop heat pipe heat exchange system according to this embodiment is applied to a reactor cooling system.

  The basic configuration of the nuclear reactor system is the same as described in FIG. In FIG. 17, the main steam pipe 54 and the like are not shown for easy understanding. In the present embodiment, the primary heat exchanger 21 is provided in the storage container 51. The secondary side heat exchanger 22 is located outside the containment vessel 51 and is installed at an altitude higher than the installation height of the primary side heat exchanger 21. The secondary heat exchanger 22 is disposed in the duct 70 and is air-cooled by the cooling air G5 that passes through the duct 70.

  This embodiment does not include the heat exchanger body 72, the flow paths 58, 59, 60, and 64, and the automatic valves 57, 67, 68, and 69, as compared with the configuration of FIG. Since the configuration of the primary side heat exchanger 21 and the secondary side heat exchanger 22, the connection configuration of the heat exchangers 21 and 22, and the configuration of the pressure accumulation tank 17 are the same as described in the sixth embodiment, Description is omitted.

  When the nuclear reactor system is in normal operation, a loop flow path comprising the heat transfer tube 1, the upper header 2, the flow path 6, the upper header 12, the heat transfer pipe 11, the lower header 13, the flow path 7, and the lower header 3, The flow path 16 and a part of the pressure accumulation tank 17 are filled with cooling water, and the automatic valve 28 and the automatic valve 29 are closed. Non-condensable gas has been removed from the loop flow path.

  When the temperature of the containment vessel 51 becomes high temperature and high pressure due to a reactor failure or the like, the automatic valve 28 and the automatic valve 29 are opened. Thereby, the vapor | steam G6 in the storage container 51 is cooled and condensed on the outer surface of the heat exchanger tube 1 of the primary side heat exchanger 21.

  Since the vapor phase volume in the storage container 51 decreases due to vapor condensation, the pressure in the storage container 51 decreases. Moreover, since the primary side heat exchanger 21 functions as a cooling device in the storage container 51, the temperature in the storage container 51 falls. The condensed water W <b> 6 generated on the outer surface of the heat transfer tube 1 falls in the storage container 51 and flows into the pressure suppression pool 62 and the storage container cavity 61.

  The condensed water W6 that has flowed into the pressure suppression pool 62 is used for steam condensation cooling water for reducing the pressure inside the containment vessel 51 or an emergency core cooling system (not shown) for injecting cooling water into the pressure vessel 52. Used as raw water.

  The condensed water W <b> 6 that has flowed into the storage container cavity 61 is used for cooling the storage container cavity 61. Furthermore, the condensed water W6 that has dropped and spread contributes to the reduction of the pressure and temperature in the storage container 51 by condensing the steam in the storage container 51 on the surface thereof.

  On the other hand, the cooling water in the heat transfer tube 1 heated by the steam in the containment vessel 51 passes through the inside of the loop flow path due to the density difference caused by the temperature difference and the gravity caused by the difference in installation position as described above. It circulates naturally and discharges the heat in the storage container 51 to the outside.

  Since the heat transfer rate of boiling heat transfer and condensation heat transfer is higher than that of natural convection, the temperature of the outer surface of the heat transfer tube 11 further increases due to the heat transferred by steam condensation in the heat transfer tube 11. Thereby, the heat removal amount to the air G5 increases.

  Since the boiling and condensing process continues in the loop flow path, the heat inside the storage container 51 can be radiated to the outside of the storage container 51 over a long period of time. During normal operation of the reactor system, since the inside of the circulation loop is filled with cooling water, there is no non-condensable gas that hinders heat transfer in the loop flow path. Therefore, it is possible to prevent a decrease in heat transfer performance in the above-described boiling and condensation heat transfer.

  In the present embodiment, even when the remote control function of the automatic valves 28 and 29 is lost due to a failure of the nuclear reactor or the like, the automatic valves 28 and 29 are opened by the fail open function. As a result, the loop heat pipe heat exchange system of the present embodiment does not need to be controlled from the outside, and automatically starts operation and continuously performs the heat removal operation.

  Configuring this embodiment like this also achieves the same operational effects as the sixth embodiment. Furthermore, in this embodiment, since the configuration can be simplified as compared with the sixth embodiment, the manufacturing cost and the reliability can be improved.

  The eighth embodiment will be described with reference to FIG. FIG. 18 is a longitudinal sectional view showing an example in which the loop heat pipe heat exchange system according to this embodiment is applied to a reactor cooling system.

  In the present embodiment, in the configuration described in FIG. 17, the primary side heat exchanger 21 is installed inside the pressure suppression pool 62. During normal operation of the nuclear reactor, the heat transfer tube 1, the upper header 2, the flow channel 6, the upper header 12, the heat transfer tube 11, the lower header 13, the flow channel 7, and the loop flow channel including the lower header 3, Then, a part of the pressure accumulating tank 17 is filled with cooling water, and the automatic valve 28 and the automatic valve 29 are closed.

  When the containment vessel 51 is in a high-temperature and high-pressure state due to a reactor failure or the like, the automatic valve 28 and the automatic valve 29 are opened. Cooling water in the pressure suppression pool 62 and steam in the wet well gas phase space 63 are cooled on the outer surface of the heat transfer tube 1.

  The cooling water temperature of the pressure suppression pool 62 decreases due to the cooling in the heat transfer tube 1. Furthermore, the vapor in the wet well gas phase space 63 condenses in the heat transfer tube 1, so that the pressure in the wet well gas phase space 63 decreases.

  When the cooling water temperature in the pressure suppression pool 62 falls below the saturation temperature, the pressure inside the wet well gas phase space 63 further drops due to vapor condensation on the surface of the cooling water. Thereby, since the vapor | steam of the space part 65 of the storage container 51 is drawn in into the pressure suppression pool 62 water through the vent pipe 66, the pressure in the storage container 51 falls.

  Condensed water generated on the outer surface of the heat transfer tube 1 in contact with the wet well gas phase space 63 is steam cooling cooling water for reducing the pressure inside the containment vessel 51 or emergency core cooling for injecting cooling water into the pressure vessel 52. Used as raw water for the system (not shown).

  The heat flow in the loop flow path of the heat exchange system and the heat release behavior from the heat transfer tube 11 of the secondary side heat exchanger 22 to the external atmosphere of the containment vessel 51 are the same as in the seventh embodiment. In addition, when the reactor control power is lost and the remote control function of the automatic valve is lost, automatic activation (automatic operation) and heat removal of the heat exchange system by the fail-open function of the automatic valve 28 and automatic valve 29 The operation continuation action is the same as in the seventh embodiment.

  Configuring this embodiment like this also achieves the same operational effects as the seventh embodiment. Further, in this embodiment, since the primary heat exchanger 21 is installed in the pressure suppression pool 62, the pressure in the wet well gas phase space 63 can be lowered, and the reliability of the nuclear reactor is improved.

  A ninth embodiment will be described with reference to FIG. FIG. 19 is a longitudinal sectional view showing an example in which the loop heat pipe heat exchange system according to this embodiment is applied to a reactor cooling system.

  In FIG. 19, only a part of the pressure vessel 52 of the nuclear reactor and a part of the wall surface of the containment vessel 51 are shown, but the overall configuration of the nuclear reactor is the same as that shown in FIGS. . In the present embodiment, the primary heat exchanger 21 is provided in the pressure vessel 52.

  A secondary heat exchanger 22 is provided in the external space of the storage container 51. The secondary side heat exchanger 22 is installed in the duct 70 at an altitude higher than the installation height of the primary side heat exchanger 21. The connection configuration between the primary side heat exchanger 21 and the secondary side heat exchanger 22 and the connection configuration between the loop flow path and the pressure accumulating tank 17 are as described with reference to FIG.

  During normal operation of the nuclear reactor, the heat transfer tube 1, the upper header 2, the flow channel 6, the upper header 12, the heat transfer tube 11, the lower header 13, the flow channel 7, and the lower header 3, and the flow channel 16 Then, a part of the pressure accumulating tank 17 is filled with cooling water, and the automatic valve 28 and the automatic valve 29 are closed.

  In particular, heat radiation from the pressure vessel 52 to the outside reduces thermal efficiency during normal operation of the nuclear reactor. Therefore, the automatic valve 28 and the automatic valve 29 are provided as close to the pressure vessel 52 as possible, and the automatic valve 28 and automatic It is important to keep the valve 29 closed.

  When a failure occurs in the nuclear reactor, the automatic valve 28 and the automatic valve 29 are opened. The steam G7 generated in the core 53 is cooled and condensed on the outer surface of the heat transfer tube 1, and the condensed water W7 falls on the cooling water surface in the pressure vessel 52 and mixes. The pressure in the pressure vessel 52 decreases due to the reduction of the gas phase volume due to the condensation of the generated steam.

  Furthermore, when the condensed water W7 is cooled on the outer surface of the heat transfer tube 1, the temperature of the condensed water W7 is lower than the saturation temperature of the cooling water. For this reason, the cooling water temperature in the pressure vessel 52 mixed with the condensed water W7 is also lowered, and the cooling of the core 53 is promoted.

  Natural circulation behavior in the loop flow path of the loop heat pipe heat exchange system in the present embodiment, movement of cooling water from the loop flow path after the start of boiling in the heat transfer tube 1 to the pressure accumulating tank 17, boiling, condensation heat transfer The heat transfer from the heat transfer tube 1 to the heat transfer tube 11 and the heat dissipation behavior to the outside of the storage container 51 are the same as in the sixth to eighth embodiments.

  Further, when the reactor control power supply is lost and the remote control function of the valve is lost, the automatic activation by the fail-open function of the automatic valve 28 and the automatic valve 29 and the continuation of the heat removal operation are continued from the sixth embodiment to the eighth. It is the same as that of an Example.

  According to the present embodiment configured as described above, the same operational effects as in the seventh embodiment can be obtained. Furthermore, in the present embodiment, the pressure in the pressure vessel 52 can be reduced by the operation of the loop heat pipe heat exchange system.

  A tenth embodiment will be described with reference to FIG. FIG. 20 is a longitudinal sectional view showing an example in which the loop heat pipe heat exchange system according to this embodiment is applied to a reactor cooling system.

  FIG. 20 shows a part of the configuration of the nuclear reactor, but the overall configuration of the nuclear reactor is the same as that shown in FIGS. 16 to 19.

  In the present embodiment, a plurality of automatic valves 28 a and 28 b are provided in the flow path 6, and a plurality of automatic valves 29 a and 29 b are provided in the flow path 7. Each of these automatic valves 28a, 28b, 29a, and 29b is connected to a distribution board 73 and a distribution board 74 connected to different distribution systems. That is, the automatic valves 28a and 29a are connected to one switchboard 73, and the automatic valves 28b and 29b are connected to the other switchboard 74.

  Here, the number of automatic valves and distribution systems is not limited to “2”. For example, it is possible to provide three systems or four systems each supplying power to two automatic valves. The number of automatic valves provided in each system is not limited to two, and may be three or more.

  During normal operation of the reactor, the loop flow path of the loop heat pipe heat exchange system is filled with cooling water, and each automatic valve is closed. If there is one automatic valve provided in each of the flow paths 6 and 7 and these automatic valves are connected to the same power distribution system, if the power distribution system fails, the flow paths 6 and 7 The automatic valves provided one by one are opened by the fail open function, and the flow paths 6 and 7 are opened. Therefore, the heat of the cooling water or steam in the pressure vessel 52 is transported to the outside of the containment vessel 51 through the flow paths 6 and 7 and is radiated, so that the thermal efficiency of the reactor system is lowered.

  On the other hand, in this embodiment, because the configuration is such that the flow paths 6 and 7 are opened and closed by a plurality of automatic valves connected to a plurality of different distribution systems, any one of the distribution systems has a failure. Also, the closing of the flow paths 6 and 7 can be maintained. Accordingly, it is possible to prevent thermal efficiency from being lowered during normal operation of the nuclear reactor.

  Configuring this embodiment like this also achieves the same effects as the seventh embodiment. Further, in this embodiment, it is possible to prevent the thermal efficiency from being lowered during the normal operation of the nuclear reactor. In addition, the structure which opens and closes the flow paths 6 and 7 of the loop heat pipe heat exchange system by a plurality of automatic valves connected to a plurality of different power distribution systems can be applied to any of the sixth to ninth embodiments.

  In addition, this invention is not limited to the above-mentioned embodiment, Various modifications can be included. For example, the above embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment. The technical features included in the present embodiment can be combined in addition to the combinations described in the claims.

  This embodiment also includes the invention of the following method. However, the following expressions are exemplary and are not limited to the method invention described below.

"A method of using a loop heat pipe heat exchange system that transports heat due to density differences in the working fluid,
The loop heat pipe heat exchange system includes a first heat exchanger provided in a heating source and having a first heat transfer tube, a second heat exchanger provided in a cooling source and having a second heat transfer tube, and the first heat exchanger. A first flow path connecting the outlet of the heat transfer tube and the inlet of the second heat transfer tube; a second flow path connecting the outlet of the second heat transfer tube and the inlet of the first heat transfer tube; An accumulator tank connected in the middle of the second flow path,
The first heat transfer tube, the second heat transfer tube, the first flow path, the second flow path, and a part of the pressure accumulation tank are filled with a working fluid in advance before starting the system.
How to operate the loop heat pipe heat exchange system. "

“A method of operating a loop heat pipe heat exchange system used in a nuclear reactor,
The nuclear reactor includes a core loaded with nuclear fuel, a pressure vessel containing the core, a main steam pipe for sending steam generated in the core to a turbine, a containment vessel containing the pressure vessel, and the containment vessel A dry well which is an internal space, a wet well which partitions a partial space in the containment vessel into a closed space and has a water pool, and a vent pipe which communicates the dry well and the pool water of the wet well. And
The loop heat pipe heat exchange system includes a first heat exchanger provided in the pressure vessel and having a first heat transfer tube, and the containment vessel at a position higher than a height direction installation position of the first heat exchanger. A second heat exchanger having a second heat transfer tube, a first flow path connecting the outlet of the first heat transfer tube and the inlet of the second heat transfer tube, and the second heat transfer tube A second flow path connecting the outlet of the first heat transfer pipe and the inlet of the first heat transfer tube, a pressure accumulation tank located outside the containment vessel and connected in the middle of the second flow path, and the second flow A second isolation valve provided in the middle of the road, which is normally closed and opened when the drive power supply is stopped,
The first heat transfer tube, the second heat transfer tube, the first flow path, the second flow path, and a part of the pressure accumulation tank are filled with a working fluid in advance.
A method of operating a loop heat pipe heat exchange system for a nuclear reactor. "

“A method of operating a loop heat pipe heat exchange system used in a nuclear reactor,
The nuclear reactor includes a core loaded with nuclear fuel, a pressure vessel containing the core, a main steam pipe for sending steam generated in the core to a turbine, a containment vessel containing the pressure vessel, and the containment vessel A dry well which is an internal space, a wet well which partitions a partial space in the containment vessel into a closed space and has a water pool, and a vent pipe which communicates the dry well and the pool water of the wet well. And
The loop heat pipe heat exchange system includes a first heat exchanger provided in the dry well and having a first heat transfer tube, and the containment vessel at a position higher than a height direction installation position of the first heat exchanger. A second heat exchanger having a second heat transfer tube, a first flow path connecting the outlet of the first heat transfer tube and the inlet of the second heat transfer tube, and the second heat transfer tube A second flow path connecting the outlet of the first heat transfer pipe and the inlet of the first heat transfer tube, a pressure accumulation tank located outside the containment vessel and connected in the middle of the second flow path, and the second flow A second isolation valve provided in the middle of the road,
The first heat transfer tube, the second heat transfer tube, the first flow path, the second flow path, and a part of the pressure accumulation tank are filled with a working fluid in advance.
A method of operating a loop heat pipe heat exchange system for a nuclear reactor. "

  1: 1st heat transfer pipe, 6: 1st flow path, 7: 2nd flow path, 8: 1st isolation valve, 9: 2nd isolation valve, 11: 2nd heat transfer pipe, 16: 3rd flow path, 17 : Pressure accumulation tank, 20: check valve, 21: first heat exchanger, 22: second heat exchanger, 23: heating source, 24: cooling source, 28: first isolation valve, 29: second isolation valve, 33: Relief valve

Claims (20)

A loop heat pipe heat exchange system that transports heat due to the density difference of the working fluid,
A first heat exchanger provided in a heating source and having a first heat transfer tube;
A second heat exchanger provided in the cooling source and having a second heat transfer tube;
A first flow path connecting the outlet of the first heat transfer tube and the inlet of the second heat transfer tube;
A second flow path connecting the outlet of the second heat transfer tube and the inlet of the first heat transfer tube;
An accumulator tank connected in the middle of the second flow path;
With
The first heat transfer tube, the second heat transfer tube, the first flow path, the second flow path, and a part of the pressure accumulation tank are filled with a working fluid in advance before starting operation,
Loop heat pipe heat exchange system. The accumulator tank is connected to the middle of the second flow path via a third flow path,
The third flow path is provided with a check valve that allows the working fluid to flow from the second flow path side to the pressure accumulation tank and prevents the working fluid from flowing from the pressure accumulation tank to the second flow path side. And
Before the start of operation, the working fluid is also filled in the third flow path in advance.
The loop heat pipe heat exchange system according to claim 1. The second flow path is provided with a second isolation valve that is normally closed and opened when the drive power supply is stopped.
The loop heat pipe heat exchange system according to any one of claims 1 and 2. The first channel is provided with a first isolation valve that is normally closed and opened when the drive power supply is stopped.
The loop heat pipe heat exchange system according to claim 3. A steam energy conversion device that converts steam energy into electrical energy is provided in the middle of the first flow path,
Furthermore, a bypass flow path for bypassing the steam energy conversion device is provided,
The working fluid flowing through the first flow path can be selectively supplied to either the steam energy conversion device or the bypass flow path.
The loop heat pipe heat exchange system according to any one of claims 1 and 2. The first isolation valve and the second isolation valve are closed before the start of operation, and are opened at the start of operation.
The loop heat pipe heat exchange system according to claim 4. The third flow path is provided with a relief valve that opens at a predetermined pressure.
The loop heat pipe heat exchange system according to claim 6. The second flow path is provided with an orifice located downstream of the connection point between the second flow path and the third flow path.
The loop heat pipe heat exchange system according to claim 6. Forming at least one branch channel in the middle of the second channel, and providing the second isolation valves having different channel cross-sectional areas in the second channel and the second branch channel,
At the start of operation, among the plurality of second isolation valves, the second isolation valve having the smaller channel cross-sectional area is opened first.
The loop heat pipe heat exchange system according to claim 6. The second heat exchanger is installed at a position higher than the first heat exchanger.
The loop heat pipe heat exchange system according to any one of claims 1 and 2. A loop heat pipe heat exchange system used in a nuclear reactor,
The nuclear reactor includes a core loaded with nuclear fuel, a pressure vessel containing the core, a main steam pipe for sending steam generated in the core to a turbine, a containment vessel containing the pressure vessel, and the containment vessel A dry well which is an internal space, a wet well which partitions a partial space in the containment vessel into a closed space and has a water pool, and a vent pipe which communicates the dry well and the pool water of the wet well. And
A first heat exchanger provided in the pressure vessel and having a first heat transfer tube;
A second heat exchanger provided outside the containment vessel at a position higher than the height direction installation position of the first heat exchanger and having a second heat transfer tube;
A first flow path connecting the outlet of the first heat transfer tube and the inlet of the second heat transfer tube;
A second flow path connecting the outlet of the second heat transfer tube and the inlet of the first heat transfer tube;
An accumulator tank located outside the containment vessel and connected in the middle of the second flow path;
A second isolation valve provided in the middle of the second flow path, normally closed, and opened when the drive power supply is stopped;
With
The first heat transfer tube, the second heat transfer tube, the first flow path, the second flow path, and a part of the pressure accumulation tank are filled with a working fluid in advance.
Loop heat pipe heat exchange system for nuclear reactors. The accumulator tank is connected to the middle of the second flow path via a third flow path,
The third flow path is provided with a check valve that allows the working fluid to flow from the second flow path side to the pressure accumulation tank and prevents the working fluid from flowing from the pressure accumulation tank to the second flow path side. And
The reactor loop heat pipe heat exchange system according to claim 11, wherein the working fluid is also filled in the third flow path in advance before the operation of the nuclear reactor. A loop heat pipe heat exchange system used in a nuclear reactor,
The nuclear reactor includes a core loaded with nuclear fuel, a pressure vessel containing the core, a main steam pipe for sending steam generated in the core to a turbine, a containment vessel containing the pressure vessel, and the containment vessel A dry well which is an internal space, a wet well which partitions a partial space in the containment vessel into a closed space and has a water pool, and a vent pipe which communicates the dry well and the pool water of the wet well. And
A first heat exchanger provided in the dry well and having a first heat transfer tube;
A second heat exchanger provided outside the containment vessel at a position higher than the height direction installation position of the first heat exchanger and having a second heat transfer tube;
A first flow path connecting the outlet of the first heat transfer tube and the inlet of the second heat transfer tube;
A second flow path connecting the outlet of the second heat transfer tube and the inlet of the first heat transfer tube;
An accumulator tank located outside the containment vessel and connected in the middle of the second flow path;
A second isolation valve provided in the middle of the second flow path;
With
The first heat transfer tube, the second heat transfer tube, the first flow path, the second flow path, and a part of the pressure accumulation tank are filled with a working fluid in advance.
Loop heat pipe heat exchange system for nuclear reactors. The accumulator tank is connected to the middle of the second flow path via a third flow path,
The third flow path is provided with a check valve that allows the working fluid to flow from the second flow path side to the pressure accumulation tank and prevents the working fluid from flowing from the pressure accumulation tank to the second flow path side. And
The reactor loop heat pipe heat exchange system according to claim 13, wherein the working fluid is also filled in the third flow path in advance before the operation of the nuclear reactor. Provided outside the first heat transfer pipe is a casing that condenses the vapor of the working fluid flowing from the main steam pipe through the introduction flow path on the outer surface side of the first heat transfer pipe,
Providing a wet well side return flow path for supplying the working fluid in the casing into the wet well;
A wet well side isolation valve is provided in the introduction channel,
The reactor loop heat pipe heat exchange system according to any one of claims 13 and 14. Provided outside the first heat transfer pipe is a casing for condensing the steam of the working fluid flowing from the main steam pipe through the introduction flow path on the heating surface side of the first heat transfer pipe,
Providing a containment vessel-side return channel for supplying the working fluid in the casing to the containment vessel cavity;
A containment vessel cavity side isolation valve is provided in the containment vessel side flow path,
The reactor loop heat pipe heat exchange system according to any one of claims 13 and 14. Provided outside the first heat transfer pipe is a casing for condensing the steam of the working fluid flowing from the main steam pipe through the introduction flow path on the heating surface side of the first heat transfer pipe,
Providing a pressure vessel side return flow path for supplying the working fluid in the casing to the pressure vessel;
A pressure vessel side isolation valve is provided in the pressure vessel side flow path;
The reactor loop heat pipe heat exchange system according to any one of claims 13 and 14. Forming a cooling duct for supplying cooling air to the second heat transfer tube;
The loop heat pipe heat exchange system for a nuclear reactor according to any one of claims 15 to 17. A first isolation valve is provided in the middle of the first flow path.
The loop heat pipe heat exchange system for a nuclear reactor according to any one of claims 13 to 18. The first isolation valve and the second isolation valve are constituted by a fail-open type automatic valve that is normally closed and opened when the drive power supply is stopped.
The reactor loop heat pipe heat exchange system according to claim 19.

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