Cooling system for beam heating element

Abstract

To provide a cooling system capable of removing decay heat of a beam heating element even in a power supply loss state.SOLUTION: A cooling system comprises a cooler for absorbing heat from a beam heating element and evaporating a first coolant that is a liquid, a condenser which is connected to an upper side of the cooler via a first pipe and condenses the evaporated first coolant, and a second pipe in which the first coolant liquefied by the condenser flows to the cooler. The first coolant is naturally circulated between the cooler and the condenser. In the cooling system, the condenser includes a condensation pipe in which the first coolant flows, and a sealed container in which the condensation pipe is stored. At least a liquefied second coolant is stored in the container in order to cool the condensation pipe from the outside of the pipe, and a pressure release device is disposed at a middle position of the first pipe and inside of the container.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a cooling system for a beam heating element. [Background technology]

[0002] In recent years, particle physics experiments using accelerators have become increasingly important. In these particle physics experiments, beams of protons, neutrons, electrons, etc. are used, and in particular, there is a demand for beams of greater intensity (higher power) as technology advances. In order to meet this demand, efforts are being made to increase the intensity (power) of beams in accelerators.

[0003] In particle physics experiments, elementary particles are generated in a target by irradiating the target with a beam from an accelerator, and the heat density of the target increases as the intensity of the beam increases. Also, in beam absorbing devices such as beam dumps used to absorb and stop the beam, the heat density of the beam absorbing devices increases as the intensity of the beam increases.

[0004] Therefore, with the recent increase in beam intensity, the heat generation density of beam heating elements such as targets and beam absorbing devices has increased significantly, and as a result, the importance of a system for cooling the beam heating element, i.e., a cooling system, has become increasingly important. Current cooling systems are mainly water-cooled systems that cool the beam heating element with a single phase of water that is forced to circulate using a driving device or the like. A water-cooled cooling system is typically configured to circulate the cooling water used to cool the beam heating element in order to continuously cool the beam heating element. Such a technology is also described in Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2001-124900 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the cooling system described above, the circulating cooling water is activated by contacting the beam heating element when cooling the beam heating element. In particular, when the accelerator operates with a proton beam, large-scale facilities and labor are required for handling and disposing of the activated cooling water during maintenance of the cooling system. Therefore, the cooling system is required to be highly robust and reliable in order to prevent the activated cooling water from leaking out to the outside in order to operate safely.

[0007] In addition, before the beam intensity increased as described above, the decay heat of the beam heating element was small. Therefore, even if the driving device in the cooling system stopped due to a power loss caused by a power outage or the like, and as a result, a situation occurred in which the cooling water could not circulate, there was little need to consider removing the decay heat of the beam heating element. However, in the current situation in which the beam intensity has increased, decay heat is generated significantly, especially in beam heating elements such as tantalum-coated tungsten targets. Therefore, measures are required to remove the decay heat of the beam heating element even in a power loss state.

[0008] An object of the present disclosure is to provide a cooling system that can remove decay heat from a beam heating element even in a state where power is lost. [Means for solving the problem]

[0009] One embodiment of the cooling system of the present disclosure is a cooling system for a beam heating element, comprising: a cooler that absorbs heat from the beam heating element and evaporates a first liquid refrigerant; a condenser connected above the cooler via a first piping and condensing the evaporated first refrigerant; and a second piping that flows the first refrigerant liquefied by the condenser to the cooler, wherein the first refrigerant naturally circulates between the cooler and the condenser, wherein the condenser comprises a condensing tube through which the first refrigerant flows, and a sealed container that accommodates the condensing tube, wherein the container accommodates at least a liquefied second refrigerant to cool the condensing tube from outside the tube, and a pressure release device is positioned within the container at a position midway along the first piping. Effect of the Invention

[0010] According to the present disclosure, a cooling system is provided that can remove decay heat from a beam heating element even in a power loss state. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a configuration diagram of an embodiment of a cooling system, illustrating normal operation (when power is applied). [Diagram 2] FIG. 2 is a diagram illustrating the configuration of an embodiment of a cooling system when power is lost. [Diagram 3] FIG. 13 is an explanatory diagram of a modified example of the cooling system. [Figure 4] XX line cross-sectional view of FIG. [Diagram 5] FIG. 13 is a schematic diagram showing a beam heating element and a cooler accommodating the beam heating element in a modified cooling system. [Figure 6A] FIG. 13 is a schematic diagram showing a beam heating element and a cooler accommodating the beam heating element in a modified cooling system. [Figure 6B] FIG. 13 is a configuration diagram (plan view) that shows a schematic diagram of a beam heating element and a cooler that houses the beam heating element in a modified example of the cooling system. [Figure 7] FIG. 13 is a schematic diagram showing a beam heating element and a cooler accommodating the beam heating element in a modified cooling system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A first embodiment of the cooling system of the present disclosure is a cooling system for a beam heating element, comprising a cooler that absorbs heat from a beam heating element and evaporates a first liquid refrigerant, a condenser connected above the cooler via a first piping and condensing the evaporated first refrigerant, and a second piping that flows the first refrigerant liquefied by the condenser to the cooler, wherein the first refrigerant naturally circulates between the cooler and the condenser, the condenser comprising a condensing tube through which the first refrigerant flows, and a sealed container that accommodates the condensing tube, the container containing at least a liquefied second refrigerant to cool the condensing tube from outside the tube, and a pressure release device is disposed within the container at a position midway along the first piping.

[0013] In the event of a power loss, the condensation of the first refrigerant in the condenser may not proceed as expected. The condensation of the first refrigerant is performed by the second refrigerant that cools the condensation tube from outside the tube, and the circulation and cooling of this second refrigerant is usually performed efficiently using electricity. Therefore, if the amount of heat generated by the beam heating element is large, there is a risk that the internal pressure of the piping (especially the first piping) in the natural circulation path will increase.

[0014] Here, in the cooling system of the first embodiment, a pressure relief device is disposed in the container at a midpoint of the first pipe. In other words, it means that a part of the natural circulation path can be intentionally weakened to control the location where the pipe may break. This pressure relief device is disposed in the container at a midpoint of the first pipe. The first coolant in the first pipe is in direct contact with the beam heating element and may be radioactive, but by bursting the first pipe in the container at the design internal pressure, leakage of the first coolant to the outside at the time of power loss is suppressed. The design internal pressure can be set to a level at which the pressure relief device will burst first among all the points in the natural circulation path.

[0015] A second embodiment of the cooling system of the present disclosure is the cooling system of claim 1, wherein in the first embodiment, the pressure release device is configured to open the first pipe in the container and allow the second refrigerant to flow into the natural circulation flow path when the internal pressure of the first pipe reaches a predetermined value.

[0016] The cooling system of the second embodiment is configured such that, when the internal pressure of the first pipe reaches a predetermined value, the pressure release device opens the first pipe and allows the second refrigerant to flow into the natural circulation flow path. Therefore, even if the condensation of the first refrigerant does not proceed as specified and cooling becomes insufficient during a power loss (such as a power outage), the second refrigerant (which is at least lower in temperature than the first refrigerant) flows into the natural circulation flow path, and cooling and natural circulation continue. Furthermore, by opening the first pipe into the container by the pressure release device, the internal pressure of the first pipe is sufficiently reduced, and secondary damage to the first pipe is also suppressed.

[0017] A third embodiment of the cooling system of the present disclosure is a cooling system according to the first embodiment, wherein the condenser is installed protruding outside the container and has a branch pipe that connects an upper part and a lower part of the container inside, and the second refrigerant is accommodated in at least a portion of the inside of the branch pipe.

[0018] The branch pipe of the cooling system of the third embodiment can function as a path for natural circulation of the second refrigerant. Even if the supply and discharge of the second refrigerant to the container are cut off due to a power loss, the branch pipe protruding to the outside maintains the circulation of the second refrigerant, which contributes to the condensation of the first refrigerant and helps maintain the functionality of the entire cooling system.

[0019] A fourth embodiment of the cooling system of the present disclosure is a cooling system in which, in the third embodiment, a first guide that opens vertically upward is disposed at a connection port between the branch pipe and the container at the upper portion to suppress the flow of gas into the branch pipe.

[0020] The cooling system of the fourth embodiment includes a first guide at the connection port between the branch pipe and the container at the upper part, which suppresses the inflow of gas (mainly the vaporized second refrigerant) into the branch pipe, thereby making the circulation of the second refrigerant through the branch pipe more efficient.

[0021] A fifth embodiment of the cooling system of the present disclosure is a cooling system in which, in the first embodiment, the condenser includes a second guide that separates an outer periphery space of the cylindrical container from an inner periphery space including the condenser tube, and the second guide is configured to communicate the outer periphery space with the inner periphery space at both vertical ends.

[0022] The second guide has a function of promoting natural circulation of the second refrigerant. Specifically, when the vaporized first refrigerant in the first pipe and the condenser tube is boiled and cooled by the second refrigerant, and the second refrigerant boils, natural circulation is induced in the inner circumferential space and the outer circumferential space due to the density difference between the density of the second refrigerant in a gas-liquid two-phase state in the inner circumferential space and the density of the second refrigerant in a liquid single-phase state in the outer circumferential space. In the cooling system of the fifth embodiment including the second guide, the circulation of the second refrigerant is not lost even in the event of a power loss, and the function of the system is easily maintained.

[0023] A sixth embodiment of the cooling system of the present disclosure is a cooling system according to the first embodiment, wherein a supply pipe and a discharge pipe for supplying and discharging the second refrigerant are connected to the container, and automatic control valves that are closed in a non-energized state are disposed in the supply pipe and the discharge pipe, respectively.

[0024] The automatic control valve of the sixth embodiment is closed in a de-energized state (e.g., when power is lost). This separates the container containing the second refrigerant from the supply and discharge systems for the second refrigerant. As described above, after power is lost, the internal pressure of the natural circulation path of the first refrigerant increases, and the activation of the pressure release device may cause the radioactive first refrigerant to be mixed into the container. However, at this time, the container is already separated from the outside (the supply and discharge systems), so the release of the radioactive first refrigerant to the outside is suppressed.

[0025] A seventh embodiment of the cooling system of the present disclosure is a cooling system according to the first embodiment, further comprising a power generation means and a heat radiator arranged above the outside of the container, the power generation means generating electricity by the airflow generated by the heat radiator.

[0026] The cooling system of the seventh embodiment is provided with a radiator above the container, so that the second refrigerant is more efficiently concentrated, and the cooling function is more easily maintained even during a power outage. One specific form of heat flow during a power outage is as follows: First, (1) the beam heating element generates heat, then (2) the heat is transferred to the first refrigerant, then (3) the first refrigerant boils and is transported to the condenser, then (4) the heat is transferred to the second refrigerant through the condensing tube, and then (5) the second refrigerant boils and becomes vapor by the amount of latent heat of evaporation.

[0027] When the power supply to the cooling system is maintained, the second refrigerant is circulated and cooled. On the other hand, during a power outage (loss of power), the second refrigerant is cooled by dissipating the latent heat of evaporation by the radiator. As a result, in the steady state during a power outage, the beam heat generation amount, the latent heat of evaporation corresponding to the boiling amount of the second refrigerant, and the amount of heat dissipated by the upper radiator are approximately equal, resulting in the effect that the boiling amount of the second refrigerant becomes equal to the condensation amount of the second refrigerant.

[0028] In addition, the (upward) air current generated by the radiator can be used for generating electricity by the power generation means described later, enabling more efficient operation.

[0029] An eighth embodiment of the cooling system of the present disclosure is the cooling system of the seventh embodiment, wherein the power obtained by the power generation means is used for monitoring a state of the cooling system.

[0030] The cooling system of the eighth embodiment is configured so that monitoring is performed using power supplied by a power generation means, so that even when power is lost, the state of the cooling system, in particular whether stable cooling is continuing, can be confirmed.

[0031] A ninth embodiment of the cooling system of the present disclosure is a cooling system in which, in the eighth embodiment, the power generation means generates power using at least one selected from the group consisting of the flow of the first refrigerant and the heat of the second refrigerant.

[0032] Even when power is lost, if the beam heating element continues to generate heat, the flow of the first refrigerant in the cooling system is maintained and the temperature rise of the second refrigerant that cools it is also maintained.Therefore, according to the 9th embodiment of the cooling system which is equipped with a power generation means that uses this to generate power, cooling operation can be continued stably even when power is lost.

[0033] A tenth embodiment of the cooling system of the present disclosure is a cooling system in which the beam heating element extends within the cooler in a direction intersecting the flow direction of the first refrigerant, and is composed of a plurality of divided elements divided into a plurality of pieces in the longitudinal direction of the beam heating element, and adjacent divided elements define a flow path of the first refrigerant within the cooler.

[0034] In the cooling system of the tenth embodiment, the beam heating element is composed of a plurality of divided elements, and adjacent divided elements define a flow path for the first coolant in the cooler. In other words, the flow path is formed by the gap between the divided elements. Therefore, the cooling efficiency of the beam heating element by the first coolant is superior. In addition, when the beam is injected from the longitudinal direction of the beam heating element, even if the beam heating element is divided, the shape can be optimized by design for secondary particle generation efficiency, so there is also an advantage that the impact is minor in terms of elementary particle generation, etc.

[0035] An eleventh embodiment of the cooling system of the present disclosure is a cooling system characterized in that the beam heating element has a plurality of through holes extending along the flow direction of the first refrigerant, and the through holes define a flow path of the first refrigerant within the cooler.

[0036] In the cooling system of the eleventh embodiment, the through-holes of the beam heating element define the flow path of the first coolant. In other words, the through-holes form the flow path. Therefore, the cooling efficiency of the beam heating element by the first coolant is superior. Another advantage is that even if the beam heating element has through-holes, the shape can be optimized for secondary particle generation efficiency by design, so that the impact is minor in terms of elementary particle generation, etc.

[0037] A twelfth embodiment of the cooling system of the present disclosure is the cooling system described in claim 1, wherein the cooler is configured so that the cross-sectional area of ​​the flow path of the first refrigerant gradually increases from the downstream side to the upstream side in the flow direction of the first refrigerant.

[0038] In the cooling system of the twelfth embodiment, the cross-sectional area of ​​the flow path of the first coolant is gradually increased from the downstream side to the upstream side. The first coolant absorbs heat from the beam heating element in the cooler and vaporizes, so that the liquid state predominates on the upstream side and the expanded gas state predominates on the downstream side. Therefore, by making the flow path area wider toward the downstream side, the first coolant can flow more smoothly. Furthermore, a configuration in which the upstream side is the beam irradiation surface is even more preferable because the upstream side, which generates more heat, can be cooled more efficiently.

[0039] In this specification, the term "beam heating element" refers to an object to be cooled by a cooling system that generates heat when irradiated with a (particle) beam. Specific examples of heat generation include nuclear heat and decay heat. Specific examples of beam heating elements include a target that is irradiated with a beam to generate elementary particles, and a beam dump that is used to absorb and / or stop the beam. In addition, the "beam" may be a beam of particles such as protons, neutrons, and electrons.

[0040] First, an embodiment of a cooling system 10 will be described with reference to Figs. 1 and 2. Fig. 1 is an explanatory diagram during normal operation (when power is applied). Fig. 2 is an explanatory diagram during power loss. The cooling system 10 has a circulation path 20 having a beam heating element 11 therein. The circulation path 20 is configured to allow a first refrigerant C1 that cools the beam heating element 11 to flow so as to circulate as a primary cooling means.

[0041] The cooling system 10 has a condenser 30 located downstream of the beam heating element 11 in the flow direction (indicated by a one-sided arrow E) of the first refrigerant C1 on the circulation path 20. The condenser 30 is configured to enable the first refrigerant C1 flowing through the circulation path 20 to be condensed. Although details will be described later, circulation path 20 includes a first pipe consisting of upward inclined pipe 20d, ascending pipe 20a, and upstream horizontal pipe 20e from the cooler 12 side accommodating beam heating element 11 to condenser 30, and a second pipe consisting of downcomer pipe 20c and downstream horizontal pipe 20f from condenser 30 to cooler 12. The first pipe mainly serves as a flow path for first refrigerant C1 vaporized by absorbing heat from beam heating element 11, and the second pipe mainly serves as a flow path for first refrigerant C1 liquefied in condenser 30.

[0042] The circulation path 20 has an ascending pipe 20a that causes the first refrigerant C1 boiled on the surface of the beam heating element 11 in a gas-liquid two-phase state to flow upward in the flow direction from the beam heating element 11 to the condenser 30. The circulation path 20 has a condensing pipe 20b that extends vertically from above to below within the condenser 30, inclined with respect to the vertical direction and detouring in the horizontal direction.

[0043] The condenser pipe 20b can condense the first refrigerant C1 sent from the riser pipe 20a and cause it to flow downward in the flow direction. For example, the condenser pipe 20b can be formed in a spiral shape. However, the shape of the condenser pipe is not limited to a spiral shape.

[0044] The circulation path 20 has a downcomer pipe 20c that causes the first refrigerant C1 condensed by the condenser pipe 20b to flow downward in a single-phase liquid state in the flow direction. The downcomer pipe 20c can be formed to extend in the vertical direction. In the circulation path 20, the first refrigerant C1 can naturally circulate in the flow direction due to the density difference between the first refrigerant C1 in the upcomer pipe 20a and the upward inclined pipe 20d and the first refrigerant C1 in the downcomer pipe 20c and the condenser pipe 20b.

[0045] The circulation path 20 has an upwardly inclined pipe 20d located between the beam heating element 11 and the rising pipe 20a in the flow direction of the first refrigerant C1. The upwardly inclined pipe 20d extends while inclining from the lower to the upper vertical direction as it moves from the beam heating element 11 to the rising pipe 20a in the flow direction of the first refrigerant C1. The rising pipe 20a is located vertically above the upwardly inclined pipe 20d. The rising pipe 20a extends vertically from the lower to the upper vertical direction.

[0046] The circulation path 20 has an upstream horizontal pipe 20e located between the rising pipe 20a and the condensing pipe 20b in the flow direction of the first refrigerant C1. The upstream horizontal pipe 20e extends from the downstream end (vertical upper end) of the rising pipe 20a in the flow direction to the upstream end (vertical upper end) of the condensing pipe 20b in the flow direction. Typically, it is assumed that the first refrigerant C1 flowing from the upstream horizontal pipe 20e into the condensing pipe 20b is at about 100°C or higher.

[0047] The circulation path 20 has a downstream horizontal pipe 20f located between the downcomer pipe 20c and the beam heating element 11 in the flow direction of the first refrigerant C1. The downstream horizontal pipe 20f extends so as to be able to send the first refrigerant C1 from the downstream end in the flow direction (the lower end in the vertical direction) of the downcomer pipe 20c to the beam heating element 11.

[0048] The condenser 30 has a sealed tank-like container 31 that contains the second refrigerant C2 therein as a secondary cooling means. The condenser pipe 20b of the circulation path 20 is immersed in the second refrigerant C2 inside the container 31.

[0049] Here, the first and second refrigerants C1, C2 are the same type of refrigerant. For example, the first and second refrigerants C1, C2 in a single liquid phase are water. In particular, the first and second refrigerants C1, C2 in a single liquid phase can be distilled water. However, the first and second refrigerants can be different types of refrigerants. For example, at least one of the first and second refrigerants can be other than distilled water. For example, at least one of the first and second refrigerants can be tap water, well water, groundwater, river water, etc. Also, a solvent other than water may be used as the refrigerant.

[0050] The condenser 30 has a supply pipe 33 that connects a lower portion of the vertical direction of the container 31 to a refrigerant supply facility (not shown) outside the cooling system 10 so as to be able to supply the second refrigerant C2 to the container 31. The condenser 30 has a discharge pipe 34 that connects an upper portion of the vertical direction of the container 31 to a refrigerant discharge facility (not shown) outside the cooling system 10 so as to be able to discharge the second refrigerant C2 from the container 31.

[0051] During normal operation (when the power source is connected), the second refrigerant C2 is supplied into the container 31 through the supply pipe 33, and the first refrigerant C1 in the condenser 30 is condensed (cooled) by convective heat transfer on the outer wall surface of the condenser 30, and the heated second refrigerant C2 is discharged from the discharge pipe 34 in a single liquid phase.

[0052] The condenser 30 has a safety valve 35 located at the vertical upper end of the container 31. The safety valve 35 is located vertically above the liquid level of the second refrigerant C2 in a single-phase liquid state inside the container 31. The safety valve 35 is configured to release gas inside the container 31 to the outside of the container 31 so that it can be recovered when the pressure inside the container 31 exceeds a predetermined allowable pressure.

[0053] The condenser 30 has a supply solenoid valve 36 that can open and close the supply pipe 33. The condenser 30 has a discharge solenoid valve 37 that can open and close the discharge pipe 34. Each of the supply and discharge solenoid valves 36, 37 is configured to be opened to allow the second refrigerant C2 to pass in an energized state, and closed to stop the passage of the second refrigerant C2 in a non-energized state. Note that the solenoid valve may be anything other than a solenoid valve as long as it is an automatically controlled valve, and may be, for example, a piezoelectric electric valve, a motor-operated valve, or the like.

[0054] The cooling system 10 has a rupture disk 21 installed in the circulation path 20. The rupture disk 21 has a breakable portion 21a that is configured to break when the pressure in the circulation path 20 reaches an allowable pressure that breaks the circulation path 20. Such a rupture disk may be either a tension type or an inversion type. The rupture disk 21 is one of pressure relief devices, and known pressure relief devices other than the rupture disk, such as a relief valve, a burst plug, and a melting valve, can also be applied to the cooling system.

[0055] The rupture disk 21 is located inside the container 31. The rupture disk 21 is located vertically below the liquid level of the second refrigerant C2 in a single-phase liquid state inside the container 31. Such a rupture disk 21 can be arranged upstream of the condensation pipe 20b in the flow direction of the first refrigerant C1. In particular, the rupture disk 21 can be arranged in a pipe connected to the condensation pipe 20b. For example, the rupture disk 21 can be arranged in the upstream horizontal pipe 20e, and in particular, the rupture disk 21 can be arranged near the condensation pipe 20b in the flow direction of the first refrigerant C1 in the upstream horizontal pipe 20e. The cooling system 10 includes one rupture disk 21, but may include two or more. In that case, the rupture disk 21 is also arranged in the container 31 at the midpoint of the first pipe or the second pipe.

[0056] Such a rupture disk 21 is configured such that, when the broken portion 21a is broken, the circulation path 20 and the container 31 are connected, and the first refrigerant C1 in a single-phase gas state in the circulation path 20 is released through the rupture disk 21 into the inside of the container 31 so as to reduce the pressure in the circulation path 20, and the second refrigerant C2 in a single-phase liquid state in the inside of the container 31 flows from the inside of the container 31 through the rupture disk 21 into the circulation path 20 to cool the beam heating element 11.

[0057] The condenser 30 has a branch pipe 32 extending outside the container 31 so as to connect the upper and lower parts of the container 31 in the vertical direction. When a boiling cooling state occurs in which the vapor of the first refrigerant C1 in the circulation path 20, which is generated by removing the decay heat of the beam heating element 11, is boiled and cooled by the second refrigerant C2 inside the container 31, the second refrigerant C2 in the container 31 naturally circulates in the container 31 and the branch pipe 32 due to the density difference between the density of the second refrigerant C2 in a gas-liquid two-phase state inside the container 31, which is generated by the boiling, and the density of the second refrigerant C2 in a liquid single-phase state in the branch pipe 32. The flow direction of the second refrigerant C2 circulating naturally in this way is indicated by a one-sided arrow F1. In particular, such a boiling cooling state occurs when power is lost. In this case, the natural circulation in the container 31 and the branch pipe 32 can increase the flow speed along the surface of the condensation pipe 20b. Therefore, the heat transfer coefficient can be improved while suppressing the transition from the nucleate boiling state to the film boiling state, and thus the heat transfer from the first refrigerant C1 to the second refrigerant C2 can be promoted.

[0058] An upper connection portion of branch pipe 32 connected to the upper part of container 31 is located vertically above condenser pipe 20b. Furthermore, the upper connection portion of branch pipe 32 is preferably located below the liquid level of the second refrigerant in container 31. Moreover, a lower connection portion of branch pipe 32 connected to the lower part of container 31 is located vertically below condenser pipe 20b. Furthermore, a first guide 32B that opens vertically upward is disposed at the connection port between the branch pipe and the container at the upper part to suppress the inflow of gas into the branch pipe. The first guide 32B is shaped like a hood that opens vertically upward, and suppresses the vapor of the second refrigerant C2 from directly entering the branch pipe 32, further promoting the natural circulation described above.

[0059] The condenser may have one or more branch pipes. When the condenser has multiple branch pipes, the multiple branch pipes are preferably arranged at intervals in the circumferential direction of the container 31 in a plan view, and more preferably are arranged at approximately equal intervals in the circumferential direction of the container 31 in a plan view. In particular, it is preferable that the condenser 30 has one to four branch pipes.

[0060] The cooling system 10 has a radiator 40 at the vertical upper end of the container 31, which exchanges heat between the second refrigerant C2 in a single-phase gas state inside the container 31 and the air outside the container 31. The radiator 40 has an airflow path 41 that passes the air outside the container 31 from the lower part of the radiator 40 in the vertical direction to the upper part of the radiator 40 in the vertical direction.

[0061] When the boiling cooling state occurs, the second refrigerant C2 inside the container 31 rises in a single-phase gas state by boiling, and is condensed by heat exchange with the air outside the container 31 that naturally convects through the airflow path 41 of the radiator 40. The direction of air flow in the radiator 40 is indicated by a one-sided arrow A.

[0062] The cooling system 10 includes a power generating means. The power generating means of the cooling system 10 includes a plurality of methods. One is a turbine type generator 22 that generates power by the flow of the first refrigerant C1 on the circulation path 20. In particular, the turbine type generator 22 may be a small turbine type generator. The turbine type generator 22 may be disposed upstream of the condensation tube 20b in the flow direction of the first refrigerant C1, and between the beam heating element 11 and the condensation tube 20b. The turbine type generator 22 may be disposed upstream of the rupture disk 21 in the flow direction of the first refrigerant C1. However, the turbine type generator may also be disposed downstream of the rupture disk in the flow direction of the first refrigerant.

[0063] The turbine type generator 22 may be disposed in a pipe connected to the condenser pipe 20b. For example, the turbine type generator 22 may be disposed in the upstream horizontal pipe 20e. However, the turbine type generator may also be disposed in an upwardly inclined pipe or a riser pipe.

[0064] The cooling system 10 has a thermoelectric element type generator 38 that generates electricity by utilizing the temperature difference between the high temperature of the second refrigerant C2 contained inside the container 31 and the low temperature of the outside atmosphere (air). The thermoelectric element type generator 38 is located vertically above the liquid surface of the second refrigerant C2 in a single-phase liquid state inside the container 31. It is also preferable that the thermoelectric element type generator 38 is disposed on the outside wall surface of the container 31 so that it can utilize the temperature difference between the high temperature of the wall surface of the container 31 and the low temperature of the outside air.

[0065] The cooling system 10 has a wind power generator 42 that generates power by the flow of air passing through the airflow path 41 of the radiator 40. The wind power generator 42 has a windmill 42a. The wind power generator 42 is configured to generate power by utilizing the rotational motion of the windmill 42a caused by the flow of air passing through the airflow path 41 of the radiator 40.

[0066] In such a cooling system 10, even when the power source is lost, the state of the cooling system 10 can be monitored using electricity generated by at least one of the power generation means (the turbine type generator 22, the thermoelectric element type generator 38, and the wind power generator 42). The instrumentation devices used for such monitoring will be described later.

[0067] The cooling system 10 has a check valve 23 configured to prevent a backflow of the first refrigerant C1 in the opposite direction to the flow direction on the circulation path 20. For example, the check valve 23 can be disposed downstream of the downcomer pipe 20c in the flow direction of the first refrigerant C1, and between the downcomer pipe 20c and the beam heating element 11. However, the location of the check valve is not limited thereto.

[0068] The cooling system 10 has a refrigerant adjustment mechanism 24 configured to adjust the liquid amount and pressure of the first refrigerant C1 on the circulation path 20. For example, an accumulator, an expansion tank, a buffer tank, or the like can be used as the refrigerant adjustment mechanism 24. For example, the refrigerant adjustment mechanism 24, which is an accumulator, can be disposed upstream of the condensation tube 20b in the flow direction of the first refrigerant C1 and between the beam heating element 11 and the condensation tube 20b. However, the location of the refrigerant adjustment mechanism is not limited to this.

[0069] The cooling system 10 has a cooler 12 that houses a beam heating element 11. The beam heating element 11 and the cooler 12 are arranged in a vacuum vessel M. The cooler 12 is configured to allow a first refrigerant C1 to flow from an inlet 12a to an outlet 12b. The beam heating element 11 extends in a direction intersecting the flow direction of the first refrigerant C1 in the circulation path 20.

[0070] The beam heating element 11 and the cooler 12 define a peripheral flow path 12c of the beam heating element 11 to allow the first coolant C1 to pass therethrough. In order to increase the critical heat flux to the beam heating element 11, the flow passage 12c around the heating element is formed narrower than the inlet 12a and the outlet 12b so that the flow velocity of the first refrigerant C1 flowing through the flow passage 12c around the heating element is greater than the flow velocity of the first refrigerant C1 flowing through the inlet 12a and the outlet 12b of the cooler 12. However, the above is only one embodiment, and it is not essential to narrow the flow passage around the beam heating element 11 more than the inlet 12a and the outlet 12b. By narrowing the flow passage as much as possible, the critical heat flux can be increased more than the pool boiling condition when the beam heating element 11 is simply installed in the cooler 12.

[0071] In such a cooling system 10, the inlet 12a is disposed at the lower end of the cooler 12 in the vertical direction. The first refrigerant C1 from the downstream horizontal pipe 20f flows into the cooler 12 through the inlet 12a. The outlet 12b is disposed at the upper end of the cooler 12 in the vertical direction. The outlet 12b also faces upward in the vertical direction. The first refrigerant C1 in the cooler 12 flows out through the outlet 12b toward the upward inclined pipe 20d.

[0072] The cooling system 10 has the following instrumentation devices. That is, the cooling system 10 has a heating element thermometer 25 configured to be able to measure the temperature of the beam heating element 11. The cooling system 10 has a first refrigerant thermometer 26 configured to be able to measure the temperature of the first refrigerant C1 flowing through the riser pipe 20a.

[0073] Furthermore, the cooling system 10 has a first refrigerant pressure gauge 27 configured to be able to measure the pressure of the first refrigerant C1 flowing through the riser pipe 20a. The cooling system 10 has a first refrigerant flow meter 28 configured to be able to measure the flow rate of the first refrigerant C1 flowing through the downstream horizontal pipe 20f.

[0074] According to the cooling system 10 of this embodiment, the first refrigerant C1 is cooled by the second refrigerant C2 in the container 31 of the condenser 30 while flowing from the ascending pipe 20a through the condensing pipe 20b to the descending pipe 20c in the circulation path 20. This cooling generates a density difference between the first refrigerant C1 in the ascending pipe 20a and the upward inclined pipe 20d and the first refrigerant C1 in the descending pipe 20c and the condensing pipe 20b, and this density difference allows the first refrigerant C1 to circulate naturally in the circulation path 20. Therefore, even when power is lost, the beam heating element 11 can be cooled by the first refrigerant C1 circulating naturally in the circulation path 20.

[0075] Furthermore, when the pressure in the circulation path 20 reaches an allowable pressure that damages the circulation path 20, the broken portion 21a of the rupture disk 21 breaks, and the circulation path 20 and the container 31 are connected by this breakage. As a result, the first refrigerant C1 in a gas single phase state in the circulation path 20 is discharged into the inside of the container 31 through the rupture disk 21 so as to reduce the pressure in the circulation path 20. In addition, the second refrigerant C2 in a liquid single phase state in the container 31 flows into the circulation path 20 from the inside of the container 31 through the rupture disk 21 to cool the beam heating element 11. Therefore, it is possible to prevent the activated first refrigerant C1 from flowing out of the circulation path 20 to the outside of the cooling system 10. Therefore, even in a power loss state, the decay heat of the beam heating element 11 can be removed, the robustness of the cooling system 10 can be improved, and the reliability of the cooling system 10 can be improved.

[0076] According to the cooling system 10, when a boiling cooling state occurs in which the vapor of the first refrigerant C1 in the circulation path 20, which is generated by removing the decay heat of the beam heating element 11, is boiled and cooled by the second refrigerant C2 inside the container 31, the second refrigerant C2 inside the container 31 boils and becomes a two-phase gas-liquid state. On the other hand, the second refrigerant C2 in the branch pipe 32 becomes a single-phase liquid state.

[0077] In this state, the second refrigerant C2 can naturally circulate in the container 31 and the branch pipe 32 due to the density difference between the density of the second refrigerant C2 in a gas-liquid two-phase state inside the container 31 and the density of the second refrigerant C2 in a single-phase liquid state in the branch pipe 32. This further suppresses the formation of layers of different temperatures in the vertical direction inside the container 31, i.e., temperature stratification, and as a result, the first refrigerant C1 in the circulation path 20 can be efficiently cooled by the second refrigerant C2 inside the container 31. Therefore, decay heat of the beam heating element 11 can be efficiently removed even in a power loss state.

[0078] According to the cooling system 10, when the second refrigerant C2 inside the container 31 rises in a single-phase gas state due to boiling in the above-mentioned boiling cooling state, the second refrigerant C2 in the single-phase gas state is condensed by heat exchange with the air outside the container 31 which naturally convects through the airflow path 41 of the radiator 40. As a result, the condensed second refrigerant C2 can return to the inside of the container 31 in a single-phase liquid state.

[0079] Such condensation can prevent the temperature of the second refrigerant C2 inside the container 31 from increasing, and as a result, the first refrigerant C1 in the circulation path 20 can be efficiently cooled by the second refrigerant C2 inside the container 31. Therefore, the decay heat of the beam heating element 11 can be efficiently removed even in a state where power is lost.

[0080] According to the cooling system 10, during normal operation when power is supplied to the cooling system 10, the second refrigerant C2 can be supplied from the refrigerant supply facility to the inside of the container 31 through the supply pipe 33, and the second refrigerant C2 can be discharged from the inside of the container 31 to the refrigerant discharge facility through the discharge pipe 34. On the other hand, even if the second refrigerant C2 in the container 31 is radioactive due to a loss of power, the supply solenoid valve 36 can prevent the second refrigerant C2 in the container 31 from flowing out to the refrigerant supply facility through the supply pipe 33, and the discharge solenoid valve 37 can prevent the second refrigerant C2 in the container 31 from flowing out to the refrigerant discharge facility through the discharge pipe 34. This can improve the robustness of the cooling system 10, and can improve the reliability of the cooling system 10.

[0081] Even when the power supply is lost, the state of the cooling system 10 can be monitored using electricity generated by at least one of the turbine type generator 22, the thermoelectric element type generator 38, and the wind power generator 42. Therefore, even when the power supply is lost, the robustness of the cooling system 10 can be improved by continuously monitoring the state of the cooling system 10, and the reliability of the cooling system 10 can be improved.

[0082] Next, a modified example of the cooling system will be described with reference to Figures 3 and 4. Unless otherwise specified, in the cooling system 50, the same components as those in the first embodiment can be described using the same names and symbols as those of the components.

[0083] The cooling system 50 has a condenser 60 located on the circulation path 20 downstream of the beam heating element 11 in the flow direction (indicated by a one-sided arrow E) of the first refrigerant C1. The condenser 60 is configured to be able to condense the first refrigerant C1 flowing through the circulation path 20. The condenser 60 is configured to provide a similar function to the condenser 30 of the first embodiment, but differs in some respects from the condenser 30 of the first embodiment.

[0084] The condenser 60 has a container 61 that contains a second refrigerant C2 therein as a secondary cooling means. The condenser 60 has a plate-shaped second guide 62 that separates an outer circumferential space located on the outer circumferential side of the inside of the container 61 from an inner circumferential space located on the inner circumferential side of the inside of the container 61, and is formed so as to communicate the outer circumferential space and the inner circumferential space at the upper and lower parts in the vertical direction of the container 61.

[0085] When a boiling cooling state occurs in which the vapor of the first refrigerant C1 in the circulation path 20, generated by the removal of decay heat from the beam heating element 11, is boiled and cooled by the second refrigerant C2 inside the container 61, the second refrigerant C2 inside the container 61 naturally circulates in the inner and outer spaces of the container 61 due to the density difference between the density of the second refrigerant C2 in a gas-liquid two-phase state in the inner space on the inner side of the second guide 62, generated by the boiling, and the density of the second refrigerant C2 in a single-phase liquid state in the outer space on the outer side of the second guide 62. The flow direction of the second refrigerant C2 that naturally circulates in this manner is indicated by a single-sided arrow F2. In particular, such boil-off conditions occur upon loss of power.

[0086] The vertical upper end of the second guide 62 is located at the vertical upper part of the container 61. Furthermore, the upper end of the second guide 62 is located vertically above the condensing tube 20b. Moreover, it is preferable that the upper end of the second guide 62 is located below the liquid level of the second refrigerant in the container 31. Meanwhile, the vertical lower end of the second guide 62 is located at the vertical lower part of the container 61. Furthermore, the lower end of the second guide 62 is located vertically below the condensing tube 20b.

[0087] In FIG. 4, the condenser 60 has two second guides 62. However, the condenser 60 may have one or more second guides 62. When the condenser 60 has multiple second guides 62, the multiple second guides 62 may be arranged at intervals in the circumferential direction of the container 61 in a plan view, and in particular, may be arranged at approximately equal intervals in the circumferential direction of the container 61 in a plan view. In this case, both ends in the width direction of each second guide 62 may be connected to the circumferential surface of the tank. In particular, it is preferable that such a condenser 60 has one to four second guides 62.

[0088] Furthermore, when the condenser 60 has one second guide 62, the second guide 62 can be formed in a substantially cylindrical shape. For example, the shape of such a second guide 62 can be a substantially cylindrical shape, a substantially polygonal cylindrical shape, or the like.

[0089] 3 and 4 again, the condenser 60 has a supply pipe 63 that connects a lower portion of the container 61 in the vertical direction to a refrigerant supply facility (not shown) outside the cooling system 50 so as to be able to supply the second refrigerant C2 to the container 61. The condenser 60 has a discharge pipe 64 that connects an upper portion of the container 61 in the vertical direction to a refrigerant discharge facility (not shown) outside the cooling system 50 so as to be able to discharge the second refrigerant C2 from the container 61.

[0090] The condenser 60 has a safety valve 65 located at the vertical upper end of the container 61. The safety valve 65 is located vertically above the liquid level of the second refrigerant C2 in a single-phase liquid state inside the container 61. The safety valve 65 is configured to release gas inside the container 61 to the outside of the container 61 when the pressure inside the container 61 exceeds a predetermined allowable pressure.

[0091] The condenser 60 has a supply solenoid valve 66 that can open and close the supply pipe 63. The condenser 60 has a discharge solenoid valve 67 that can open and close the discharge pipe 64. Each of the supply and discharge solenoid valves 66, 67 is configured to be opened in an energized state to allow the second refrigerant C2 to pass through, and to be closed in a non-energized state to stop the passage of the second refrigerant C2.

[0092] Furthermore, the cooling system 50 has a thermoelectric element type generator 68 that generates electricity using the heat of the second refrigerant C2 inside the container 61. The thermoelectric element type generator 68 is located vertically above the liquid level of the second refrigerant C2 in a single-phase liquid state inside the container 61. As a specific embodiment, the thermoelectric element type generator 68 is disposed on the outer wall surface of the container 61, and generates electricity by utilizing the temperature difference between the high temperature of the wall surface and the low temperature of the outside air.

[0093] According to the cooling system 50, when a boiling cooling state occurs in which the vapor of the first refrigerant C1 in the circulation path 20, which is generated by removing the decay heat of the beam heating element 11, is boiled and cooled by the second refrigerant C2 inside the container 61, the second refrigerant C2 in the inner peripheral space of the container 61 boils and becomes a two-phase gas-liquid state. On the other hand, the second refrigerant C2 in the outer peripheral space of the container 61 becomes a single-phase liquid state.

[0094] In this state, the second refrigerant C2 can naturally circulate in the inner and outer spaces of the container 61 due to the density difference between the density of the second refrigerant C2 in a gas-liquid two-phase state in the inner space of the container 61 and the density of the second refrigerant C2 in a single-phase liquid state in the outer space of the container 61. This further suppresses the occurrence of temperature stratification inside the container 61, and as a result, the first refrigerant C1 in the circulation path 20 can be efficiently cooled by the second refrigerant C2 inside the container 61. Therefore, decay heat of the beam heating element 11 can be efficiently removed even in a power loss state.

[0095] A modified example of the cooling system will be described with reference to Fig. 5. Unless otherwise specified, in the cooling system 70, the same components as those in the above-described embodiment can be described using the same names and symbols as those of the components.

[0096] The cooling system 70 has a beam heating element 71 and a cooler 72 as described below. The beam heating element 71 and the cooler 72 are configured to provide similar functions to the beam heating element 11 and the cooler 12 described above, respectively, but differ from the beam heating element 11 and the cooler 12 in some respects.

[0097] The beam heating element 71 and the cooler 72 are placed in a vacuum vessel M (shown in Figs. 1 to 3). The beam heating element 71 extends in a direction intersecting the flow direction of the first refrigerant C1. Furthermore, the beam heating element 71 is divided into a plurality of divided elements in the longitudinal direction. Each divided element has a heat flux of 100 kW / m 2 ~1000kW / m 2 The structure is formed so that:

[0098] The length of the divided elements in the beam incidence direction increases as the divided elements move in the beam incidence direction. The cooler 72 accommodates the beam heating element 71. The cooler 72 is configured to allow a first coolant C1 to flow from an inlet 72a to an outlet 72b. The beam heating element 71 and the cooler 72 define a heating element peripheral flow path 72c that allows the first coolant C1 to pass through.

[0099] In order to increase the critical heat flux to the beam heating element 71, the heating element peripheral flow passage 72c is formed narrower than the inlet 72a and the outlet 72b so that the flow velocity of the first refrigerant C1 flowing through the heating element peripheral flow passage 72c is greater than the flow velocity of the first refrigerant C1 flowing through the inlet 72a and the outlet 72b of the cooler 72. However, the above is only one embodiment, and it is not essential to narrow the peripheral flow passage 72c of the beam heating element 71 narrower than the inlet 72a and the outlet 72b. By narrowing the flow passage as much as possible, the critical heat flux can be increased more than the pool boiling condition when the heater is simply installed in a cooler.

[0100] The inlet 72a is disposed at the lower end of the cooler 72 in the vertical direction. The first refrigerant C1 from the downstream horizontal pipe 20f flows into the cooler 72 through the inlet 72a. The outlet 72b is disposed at the upper end of the cooler 72 in the vertical direction. The outlet 72b also faces vertically upward. The first refrigerant C1 in the cooler 72 flows out through the outlet 72b toward the upward inclined pipe 20d.

[0101] According to the cooling system 70, the flow velocity of the first refrigerant C1 passing between the multiple divided elements of the beam heating element 71 can be efficiently made higher than the flow velocity of the first refrigerant C1 flowing through the inlet 72a and the outlet 72b of the cooler 72. Therefore, the critical heat flux for the beam heating element 71 can be efficiently increased.

[0102] 6A and 6B, a modified example of the cooling system 80 will be described. Unless otherwise specified, in the cooling system 80, the same components as those in the above-described embodiment can be described using the same names and symbols as those of the components.

[0103] The cooling system 80 has the following beam heating element 81 and cooler 82. The beam heating element 81 and cooler 82 are configured to provide similar functions to the beam heating element 11 and cooler 12 of the first embodiment, respectively, but differ in some respects from the beam heating element 11 and cooler 12 of the first embodiment, respectively.

[0104] The beam heating element 81 and the cooler 82 are disposed within a vacuum vessel M (shown in Figs. 1 to 3). The beam heating element 81 is formed to have a plurality of through-holes 81a extending along the flow direction of the first refrigerant C1. Although not specifically shown, a torsion plate formed by twisting an elongated plate around its longitudinal axis can be disposed inside all or some of the plurality of through-holes.

[0105] Beam heating element 81 extends in a direction intersecting the flow direction of first refrigerant C1. Cooler 82 accommodates beam heating element 81. Cooler 82 is configured to allow first refrigerant C1 to flow from inlet 82a to outlet 82b.

[0106] A heat generating element peripheral flow passage 82c is defined by the beam heat generating element 81 and the cooler 82 so as to allow the first coolant C1 to pass through. In order to increase the critical heat flux to the beam heat generating element 81, the heat generating element peripheral flow passage 82c is formed narrower than the inlet 82a and the outlet 82b so that the flow rate of the first coolant C1 flowing through the heat generating element peripheral flow passage 82c is greater than the flow rate of the first coolant C1 flowing through the inlet 82a and the outlet 82b of the cooler 82. However, the above is only one embodiment, and it is not essential to narrow the peripheral flow passage 82c of the beam heating element 81 narrower than the inlet 82a and the outlet 82b. By narrowing the flow passage as much as possible, the critical heat flux can be increased more than the pool boiling condition when the heater is simply installed in a cooler.

[0107] The inlet 82a is disposed at the lower end of the cooler 82 in the vertical direction. The first refrigerant C1 from the downstream horizontal pipe 20f flows into the cooler 82 through the inlet 82a. The outlet 82b is disposed at the upper end of the cooler 82 in the vertical direction. The outlet 82b also faces upward in the vertical direction. The first refrigerant C1 in the cooler 82 flows out through the outlet 82b toward the upward inclined pipe 20d.

[0108] According to the cooling system 80 of this embodiment, the flow velocity of the first refrigerant C1 passing through the multiple through holes 81a in the beam heating element 81 can be efficiently made higher than the flow velocity of the first refrigerant C1 flowing through the inlet 82a and the outlet 82b of the cooler 82. Therefore, the critical heat flux for the beam heating element 81 can be efficiently increased. However, the above is only one embodiment, and it is not essential to narrow the peripheral flow passage 82c of the beam heating element 81 narrower than the inlet 82a and the outlet 82b. By narrowing the flow passage as much as possible, the critical heat flux can be increased more than the pool boiling condition when the heater is simply installed in a cooler.

[0109] A modified example of the cooling system will be described with reference to Fig. 7. Unless otherwise specified, in the cooling system 90, the same components as those in the above-described embodiment can be described using the same names and symbols as those of the components.

[0110] The cooling system 90 has the following beam heating element 91 and cooler 92. The beam heating element 91 and cooler 92 are configured to provide similar functions to the beam heating element 11 and cooler 12 of the first embodiment, respectively, but differ in some respects from the beam heating element 11 and cooler 12 of the first embodiment.

[0111] The beam heating element 91 and the cooler 92 are disposed within a vacuum vessel M (shown in Figs. 1 to 3). The beam heating element 91 extends in a direction intersecting the flow direction of the first refrigerant C1. The cooler 92 accommodates the beam heating element 91. The cooler 92 is configured to allow the first refrigerant C1 to flow from its inlet 92a to its outlet 92b. The inlet 92a of the cooler 92 is disposed away from the outlet 92b of the cooler 92 on the entrance side of the beam B incident on the beam heating element 91 in the longitudinal direction of the beam heating element 91.

[0112] A heat generating element peripheral flow passage 92c is defined by the beam heat generating element 91 and the cooler 92 so as to allow the first coolant C1 to pass through. In order to increase the critical heat flux to the beam heat generating element 91, the heat generating element peripheral flow passage 92c is formed narrower than the inlet 92a and the outlet 92b so that the flow rate of the first coolant C1 flowing through the heat generating element peripheral flow passage 92c is greater than the flow rate of the first coolant C1 flowing through the inlet 92a and the outlet 92b of the cooler 92. However, the above is only one embodiment, and it is not essential to narrow the peripheral flow passage 92c of the beam heating element 91 narrower than the inlet 92a and outlet 92b. By narrowing the flow passage as much as possible, the critical heat flux can be increased more than the pool boiling condition when the heater is simply installed in a cooler.

[0113] Furthermore, the flow path 92c around the heating element is formed to narrow from the outlet 92b of the cooler 92 to the inlet 92a of the cooler 92 in the longitudinal direction of the beam heating element 91 so that the flow rate of the first refrigerant C1 flowing through the flow path 92c around the heating element increases from the outlet 92b of the cooler 92 to the inlet 92a of the cooler 92 in the longitudinal direction of the beam heating element 91.

[0114] In such a cooler 92, the inlet 92a is disposed at the lower end in the vertical direction of the cooler 92. The first refrigerant C1 from the downstream horizontal pipe 20f flows into the cooler 92 through the inlet 92a. The outlet 92b is disposed at the upper end in the vertical direction of the cooler 92. The outlet 92b also faces upward in the vertical direction. The first refrigerant C1 in the cooler 92 flows out through the outlet 92b toward the upward inclined pipe 20d.

[0115] According to the cooling system 90 of this embodiment, the flow velocity of the first refrigerant C1 passing through the heat generating element peripheral flow passage 92c as described above can be efficiently made higher than the flow velocity of the first refrigerant C1 flowing through the inlet 92a and the outlet 92b of the cooler 92. Therefore, the critical heat flux for the beam heating element 91 can be efficiently increased. However, the above is only one embodiment, and it is not essential to narrow the peripheral flow passage 92c of the beam heating element 91 narrower than the inlet 92a and outlet 92b. By narrowing the flow passage as much as possible, the critical heat flux can be increased more than the pool boiling condition when the heater is simply installed in a cooler. [Explanation of symbols]

[0116] 10…Cooling system 11...beam heating element, 12...cooler, 12a...inlet, 12b...outlet, 12c...flow passage around heating element 20...circulation path, 20a...rising pipe, 20b...condensation pipe, 20c...downcoming pipe, upward inclined pipe...20d, upstream horizontal pipe...20e, downstream horizontal pipe...20f, 21...rupture disk, 21a...broken part, 22...turbine type generator 30...condenser, 31...container, 32...branch pipe, 33...supply pipe, 34...discharge pipe, 35...safety valve, 36...supply solenoid valve, 37...discharge solenoid valve, 38...thermoelectric element type generator 40...heat sink, 41...airflow path, 42...wind power generator 50…Cooling system 60... condenser, 61... container, 62... second guide, 63... supply pipe, 64... discharge pipe, 65... safety valve, 66... ​​supply solenoid valve, 67... discharge solenoid valve, 68... thermoelectric element type generator 70…Cooling system 71: Beam heating element, 72: Cooler, 72a: Inlet, 72b: Outlet, 72c: Flow passage around heating element 80…Cooling system 81: Beam heating element, 81a: Through hole, 82: Cooler, 82a: Inlet, 82b: Outlet, 82c: Flow path around heating element 90…Cooling system 91: Beam heating element, 92: Cooler, 92a: Inlet, 92b: Outlet, 92c: Flow passage around heating element C1: First refrigerant, C2: Second refrigerant M…Vacuum container

Claims

1. a cooler that absorbs heat from the beam heating element and evaporates a first refrigerant that is a liquid; a condenser connected to an upper portion of the cooler via a first pipe and configured to condense the evaporated first refrigerant; a second pipe for causing the first coolant liquefied in the condenser to flow to the cooler, wherein the first coolant naturally circulates between the cooler and the condenser, The condenser includes a condensation pipe through which the first refrigerant flows, and a sealed container that accommodates the condensation pipe. The container contains at least a liquefied second refrigerant for cooling the condenser tube from outside the tube, A cooling system, wherein a pressure relief device is disposed midway through the first pipe and within the vessel.

2. 2. The cooling system of claim 1, wherein the pressure relief device is configured to open the first pipe in the container and allow the second refrigerant to flow into the natural circulation path when an internal pressure of the first pipe reaches a predetermined value.

3. The condenser is 2. The cooling system according to claim 1, further comprising a branch pipe protruding from the outside of the container and communicating an upper part and a lower part of the container therewithin, and at least a portion of the inside of the branch pipe contains the second refrigerant.

4. 4. The cooling system according to claim 3, wherein a first guide that is open vertically upward is disposed at a connection port between the branch pipe and the container in the upper portion, the first guide preventing gas from flowing into the branch pipe.

5. the condenser includes a second guide that divides an outer circumferential space of the cylindrical container from an inner circumferential space including the condensation tube, The cooling system according to claim 1 , wherein the second guide is configured to communicate between the outer periphery side space and the inner periphery side space at both vertical ends.

6. 2. The cooling system according to claim 1, wherein a supply pipe and a discharge pipe for supplying and discharging the second refrigerant are connected to the container, and automatic control valves that are closed in a non-energized state are disposed in the supply pipe and the discharge pipe, respectively.

7. Further comprising a power generating means and a radiator disposed above the outside of the container, 2. The cooling system according to claim 1, wherein the power generating means generates power by using an airflow generated by the radiator.

8. 8. The cooling system of claim 7, wherein the power generated by the power generating means is used to monitor a condition of the cooling system.

9. 9. The cooling system according to claim 8, wherein the power generating means generates power using at least one selected from the group consisting of the flow of the first refrigerant and heat of the second refrigerant.

10. 2. The cooling system of claim 1, wherein the beam heating element extends in the cooler in a direction intersecting the flow direction of the first coolant and is composed of a plurality of divided elements divided into a plurality of pieces in the longitudinal direction of the beam heating element, and adjacent divided elements define a flow path of the first coolant in the cooler.

11. The cooling system of claim 1, characterized in that the beam heating element has a plurality of through holes extending along a flow direction of the first coolant, and the through holes define a flow path of the first coolant within the cooler.

12. The cooling system according to claim 1 , wherein the cooler is configured such that a cross-sectional area of ​​a flow path of the first refrigerant gradually increases from a downstream side to an upstream side in a flow direction of the first refrigerant.

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