Heat exchanger and nuclear reactor

Abstract

This heat exchanger comprises a heat reception part that receives heat from the outside and evaporates a liquid-phase working fluid, a heat radiation part that condenses gas-phase working fluid that has flowed in from the heat reception part and radiates heat to the outside, and a circulation part that circulates the working fluid between the heat reception part and the heat radiation part. The heat reception part has an evaporator that evaporates the liquid-phase working fluid and a heat reception part casing that accommodates the evaporator, the heat radiation part has a condensation part that condenses the gas-phase working fluid and a heat radiation part casing that accommodates the condensation part, and the circulation part has a vapor pipe that allows gas-phase working fluid that has been discharged from the evaporator to flow to the condensation part, a reservoir that stores liquid-phase working fluid that has flowed in from the condensation part in an internal space and allows the working fluid in the internal space to flow to the evaporator, and a circulation part casing that accommodates the vapor pipe and the reservoir and is connected to the heat reception part casing and the heat radiation part casing.

Description

Heat Exchanger and Nuclear Reactor

[0001] The present disclosure relates to a heat exchanger and a nuclear reactor.

[0002] Conventionally, nuclear reactors provided with heat pipes for heat removal to simplify the core structure are known. For example, Patent Document 1 discloses a nuclear reactor in which a large number of small-diameter heat pipes are arranged in the core. This heat pipe functions as a heat exchanger and can transfer a large amount of heat even with a small volume.

[0003] In addition, Patent Document 2 discloses an apparatus including: a storage section that stores a liquid-phase fluid in which a heat-generating body that generates heat is immersed; and a cylindrical section that is provided along the vertical direction in the storage section, has openings on the upper side and the lower side respectively, and surrounds the heat-generating body. The cylindrical section guides the gas-phase fluid evaporated by the heat of the heat-generating body toward the upper side in the storage section. Further, in the apparatus, the gas-phase fluid is cooled at the upper side in the storage section, and the condensed liquid-phase fluid flows toward the lower side in the storage section.

[0004] In addition, Patent Document 3 discloses an apparatus including: a heat-generating body; and a heat exchanger that has an evaporator which absorbs heat from the heat-generating body to evaporate a liquid-phase working fluid, condenses the gas-phase working fluid flowing out of the evaporator, and circulates the condensed working fluid back to the evaporator. The apparatus has a pressing mechanism where, in a state where the heat-generating body and the evaporator are in contact with each other, as one of the heat-generating body and the evaporator slides relative to the other, the heat-generating body and the evaporator press against each other.

[0005] Japanese Patent No. 6633471, Japanese Unexamined Patent Application Publication No. 2024-46477, Japanese Unexamined Patent Application Publication No. 2021-134956

[0006] By the way, in recent years, there has been a demand for further improvement in the power generation efficiency of nuclear reactors, and it is desired to achieve higher heat transfer performance for heat pipes used in nuclear reactors. Accordingly, an object of the technology disclosed in the present specification is to provide a heat exchanger or the like with improved heat transfer performance.

[0007] The technology disclosed herein is a heat exchanger comprising: a heat receiving section that receives heat from the outside to evaporate a liquid-phase working fluid; a heat dissipation section that condenses a gaseous-phase working fluid flowing in from the heat receiving section and releases heat to the outside; and a circulation section that circulates the working fluid between the heat receiving section and the heat dissipation section, wherein the heat receiving section comprises an evaporator for evaporating the liquid-phase working fluid and a heat receiving section casing for housing the evaporator; the heat dissipation section comprises a condensing section for condensing the gaseous-phase working fluid and a heat dissipation section casing for housing the condensing section; and the circulation section comprises a steam pipe for discharging the gaseous-phase working fluid discharged from the evaporator to the condensing section; a reservoir for storing the liquid-phase working fluid flowing in from the condensing section in an internal space and for discharging the working fluid from the internal space to the evaporator; and a circulation section casing for housing the steam pipe and the reservoir and connected to the heat receiving section casing and the heat dissipation section casing.

[0008] According to this disclosure, it is possible to provide heat exchangers and the like with improved heat transfer performance.

[0009] This figure shows the schematic configuration of the loop heat pipe according to this embodiment. This is an axial cross-sectional view showing the loop heat pipe according to this embodiment. (a) is a cross-sectional view taken from the IIIa-IIIa plane of Figure 2, (b) is a cross-sectional view taken from the IIIb-IIIb plane of Figure 2, and (c) is a cross-sectional view taken from the IIIc-IIIc plane of Figure 2. This is a perspective view of the wick. (a) is a cross-sectional view taken from the Va-Va plane of Figure 2, (b) is a cross-sectional view taken from the Vb-Vb plane of Figure 2, and (c) is a cross-sectional view taken from the Vc-Vc plane of Figure 2. This is a perspective view of the heat dissipation section. (a) is a perspective view of the steam pipe, and (b) is a perspective view of the reservoir. (a) is a cross-sectional view taken from the VIIIa-VIIIa plane of Figure 2, and (b) is a cross-sectional view taken from the VIIIb-VIIIb plane of Figure 2. This is a perspective view of the secondary wick. This is an axial cross-sectional view of the heat receiving section and the circulation section. This is an axial cross-sectional view of the heat dissipation section. (a) is a diagram illustrating a reactor equipped with loop heat pipes, (b) is a cross-sectional view of the reactor core cut along the XIIb-XIIb plane of (a), and (c) is an enlarged view of XIIc of (b). This diagram illustrates Modification 1. (a) to (d) are diagrams illustrating Modification 2. This diagram illustrates Modification 3. (a) to (e) are schematic diagrams illustrating Modification 4.

[0010] The embodiment will be described in detail below with reference to the attached drawings. <Outline configuration of the heat pipe> Figure 1 is a diagram showing the outline configuration of the loop heat pipe 100 according to this embodiment. First, the outline configuration of the loop heat pipe 100 to which this embodiment is applied will be described with reference to Figure 1. In the following description, the outline configuration and operation of the loop heat pipe 100 will be described, followed by a detailed description of each part.

[0011] The loop heat pipe 100 is configured to cool a heat-generating element RC, which is the core of a nuclear reactor, by circulating a working fluid without supplying external power. The loop heat pipe 100 is formed in a straight tubular shape and extends long in the axial direction (one direction). In other words, the loop heat pipe 100 is formed in a rod shape. The outer diameter of the loop heat pipe 100 is, for example, in the range of 5 mm to 100 mm, more preferably in the range of 15 mm to 30 mm. The total length of the loop heat pipe 100 is, for example, in the range of 0.1 m to 10 m, more preferably in the range of 0.5 m to 4 m. The heat flux of the loop heat pipe 100 is 5 W / cm². ２ That's all. A comfortable 20 W / cm² ２ That's all.

[0012] This loop heat pipe 100 includes a heat receiving section 101 that receives heat from the heat-generating element RC and evaporates the liquid-phase working fluid, a heat dissipation section 102 that condenses the gaseous-phase working fluid that flows in from the heat receiving section 101 and releases heat to the outside, and a circulation section 103 that circulates the working fluid between the heat receiving section 101 and the heat dissipation section 102.

[0013] The heat receiving section 101 is provided at one end (upper side in Figure 1) of the rod-shaped loop heat pipe 100. The heat receiving section 101 utilizes the latent heat of vaporization of the working fluid to cool the heat generating element RC, and evaporates the working fluid inside the heat receiving section 101. The heat dissipation section 102 is provided at the other end (lower side in Figure 1) of the rod-shaped loop heat pipe 100. The heat dissipation section 102 dissipates heat from the working fluid vaporized in the heat receiving section 101, causing it to liquefy. The circulation section 103 is provided in the rod-shaped loop heat pipe 100 between the heat receiving section 101 and the heat dissipation section 102. That is, the circulation section 103 is provided in the central part of the rod-shaped loop heat pipe 100. The circulation unit 103 guides the gaseous working fluid from the heat receiving unit 101 to the heat dissipation unit 102, and also guides the liquid working fluid from the heat dissipation unit 102 to the heat receiving unit 101.

[0014] The loop heat pipe 100 is filled with a working fluid that undergoes a phase change between the liquid and gas phases. Examples of working fluids include water, alcohol, and ammonia. In particular, in high-temperature regions (300 to 2000°C), sodium, sodium-potassium alloy, lithium, potassium, rubidium, cesium, and mercury are preferred as working fluids.

[0015] Furthermore, the casings of the heat receiving section 101, the heat dissipation section 102, and the circulation section 103 (heat receiving section casing 110, heat dissipation section casing 130, and circulation section casing 160, which will be described later) are made of, for example, SUS. In particular, in the high-temperature range (300 to 2000°C), stainless steel, titanium, niobium, niobium alloy, molybdenum, molybdenum alloy, tungsten, tungsten alloy, tantalum, tantalum alloy, Inconel, Hastelloy®, and Haynes are suitable for each casing. The plate thickness of each casing is, for example, 1 mm.

[0016] <Operation of the Loop Heat Pipe> Next, the operation of the loop heat pipe 100 will be explained with reference to Figure 1. The heat generated in the heating element RC is transferred to the heat receiving section 101 (see arrow C1). The working fluid that has absorbed the heat in the heat receiving section 101 vaporizes (see arrow A1) and flows through the circulation section 103 to the heat dissipation section 102 (see arrow A2). The working fluid sent to the heat dissipation section 102 releases heat (see arrow C2) and liquefies. The liquefied working fluid then flows through the reservoir 180 (see arrow A3) and back to the heat receiving section 101 (see arrow A4).

[0017] In this way, the heat generated in the heat-generating element RC is transported from the heat-receiving section 101 to the heat-dissipating section 102 as described above. That is, the heat-generating element RC is cooled by the circulation of the working fluid inside the loop heat pipe 100, which is formed in the shape of a long rod in one direction.

[0018] In the following explanation, the axial direction of the loop heat pipe 100 may simply be referred to as the axial direction. Furthermore, the axial direction from the heat dissipation section 102 toward the heat receiving section 101 may be referred to as the axial direction one, and the axial direction from the heat receiving section 101 toward the heat dissipation section 102 may be referred to as the axial direction other. Also, the circumferential direction of the loop heat pipe 100 may simply be referred to as the circumferential direction. Also, the radial direction of the loop heat pipe 100 may simply be referred to as the radial direction.

[0019] <Configuration of the heat receiving section> Figure 2 is an axial cross-sectional view showing the loop heat pipe 100 according to this embodiment. Figure 3(a) is a cross-sectional view taken from the plane IIIa-IIIa of Figure 2, (b) is a cross-sectional view taken from the plane IIIb-IIIb of Figure 2, and (c) is a cross-sectional view taken from the plane IIIc-IIIc of Figure 2. Next, each component constituting the loop heat pipe 100 will be described in detail with reference to Figures 2 and 3.

[0020] As shown in Figure 2, the heat receiving section 101 includes a heat receiving section casing 110 that receives heat from the heat generating element RC, a wick 120 housed inside the heat receiving section casing 110, and a secondary wick 190 (details will be described later) provided inside the wick 120.

[0021] The heat receiving section casing 110 is a hollow tubular member, with one end in one axial direction closed and the other end in the other axial direction open. This heat receiving section casing 110 has a heat receiving end wall (tip portion) 111 formed in the shape of a disc at one end in the axial direction, and a heat receiving outer peripheral wall 115 that extends from the outer peripheral edge of the heat receiving end wall 111 in the other axial direction. As shown in Figures 3(a) to (c), the heat receiving outer peripheral wall 115 has an annular cross-sectional shape perpendicular to the axial direction. Also, as shown in Figure 2, one end of the heat receiving outer peripheral wall 115 and the outer peripheral edge of the heat receiving end wall 111 are connected such that the cross-sectional contour is arc-shaped. For the sake of explanation in this specification, the connected portion with an arc-shaped cross-sectional contour is referred to as one end of the heat receiving outer peripheral wall 115 and as a part of the heat receiving outer peripheral wall 115.

[0022] Figure 4 is a perspective view of the wick 120. The wick 120 is a so-called porous material, and is a component made of porous metal. The wick 120 has so-called macropores with a pore diameter larger than 50 nm. Specifically, the effective pore diameter (or average pore diameter) of the wick 120 is, for example, 0.1 μm to 25 μm. This average pore diameter was measured by the bubble point method, but it may be measured by other measurement methods. The porosity of the wick 120 is, for example, 25% to 70%. The wick 120 generates capillary force in the working fluid, and as a result moves the working fluid.

[0023] As shown in Figure 4, the wick 120 is a cylindrical member, with one end on the axial side closed and the other end on the axial side open. The wick 120 has one circular end face 121 on one axial side, another circular end face 122 (not shown) on the other axial side, and a wick center hole 123 (see Figure 2) that extends axially from the radial center. This wick center hole 123 opens into the other end face 122 and extends from this opening to the vicinity of the one end face 121.

[0024] As shown in Figure 4, the outer circumference 124 of the wick 120 has a plurality of elongated grooves 125 that allow evaporated working fluid to flow along the axial direction, a collection groove 126 that communicates with the plurality of elongated grooves 125 and collects the working fluid, and a discharge groove 127 that discharges the working fluid from the collection groove 126 in the other axial direction. Note that in Figure 4, the wick 120 is shown at a different angle (reverse direction) than in Figures 6 to 8, which will be described later, so that the discharge groove 127 can be seen.

[0025] The elongated groove 125 extends from the vicinity of one end face 121 to the vicinity of the other end face 122 of the outer circumference 124. In other words, the elongated groove 125 is not formed in the region on one side of the outer circumference 124 in the axial direction. To explain further, in the elongated groove 125, one side in the axial direction is closed, and the other side in the axial direction is open. In addition, multiple elongated grooves 125 are formed at intervals in the circumferential direction. As shown in Figure 3(a), the elongated groove 125 has a rectangular cross-sectional shape perpendicular to the axial direction. In other words, multiple wick protrusions 128 with a rectangular cross-sectional shape protrude from the bottom surface of the elongated groove 125 on the outer circumference 124 of the wick 120.

[0026] As shown in Figure 3(b), the convergence groove 126 extends circumferentially near the other end face 122 of the outer circumference 124. Also, as shown in Figure 4, the convergence groove 126 connects the ends of the multiple long grooves 125 on the other axial side. As shown in Figure 4, the discharge groove 127 extends axially from the convergence groove 126 to the other end face 122. As shown in Figure 3(c), the discharge groove 127 has a fan-shaped cross-section perpendicular to the axial direction. That is, the discharge groove 127 is part of an annular shape in the cross-section perpendicular to the axial direction.

[0027] Here, as shown in Figure 2, the outer periphery 124 and one end face 121 of the wick 120 are continuous along one end of the heat-receiving outer periphery wall 115 such that the cross-sectional contour is arc-shaped. In this specification, for the sake of explanation, the portion with the arc-shaped cross-sectional contour is included in the outer periphery 124 of the wick 120. The outer periphery 124 of the wick 120 is in contact with the heat-receiving outer periphery wall 115, and the one end face 121 is in contact with the heat-receiving one end wall 111. That is, the wick 120 is positioned without gaps with the heat-receiving outer periphery wall 115 on one axial side inside the heat-receiving outer periphery wall 115. To further explain, the wick 120 is installed with one axial side pressed against the inside of the heat-receiving outer periphery wall 115. In this state, the wick 120 is housed in the heat-receiving casing 110.

[0028] <Configuration of the heat dissipation section> Figure 5(a) is a cross-sectional view taken from the Va-Va plane of Figure 2, (b) is a cross-sectional view taken from the Vb-Vb plane of Figure 2, and (c) is a cross-sectional view taken from the Vc-Vc plane of Figure 2. Figure 6 is a perspective view of the heat dissipation section 102. As shown in Figure 2, the heat dissipation section 102 has a heat dissipation section casing 130 formed in the shape of a hollow tube and a condensation section 140 housed in the heat dissipation section casing 130.

[0029] As shown in Figure 6, the heat dissipation casing 130 has a ring-shaped ring end wall 131 at one end in the axial direction, a heat dissipation outer circumferential wall 135 extending from the outer peripheral edge of the ring end wall 131 in the other axial direction, and a disc-shaped heat dissipation base end wall 137 at the other end in the axial direction. As shown in Figure 5(a), the ring end wall 131 extends in a ring shape from the circumferential starting end 132 to the ending end 133 when viewed from the axial direction, i.e., it extends along the circumferential direction, and as shown in Figure 6, it is formed to be inclined from the starting end 132 to the ending end 133. More specifically, a step is formed in the axial direction between the starting end 132 and the ending end 133 of the ring end wall 131, and it extends in an annular shape from the starting end 132 to the ending end 133, moving away in the other axial direction as it proceeds circumferentially. Near the starting end 132 of the ring end wall 131, a steam pipe outlet 134 (details will be described later) is formed that opens in the axial direction. As shown in Figures 5(a) to (c), the heat dissipation outer periphery wall 135 has a circular cross-sectional shape perpendicular to the axial direction. Also, as shown in Figure 2, the other end of the heat dissipation outer periphery wall 135 and the outer edge of the heat dissipation base end wall 137 are connected such that the cross-sectional contour is arc-shaped.

[0030] As shown in Figure 6, the condensation section 140 has a spiral channel 141 where the gaseous working fluid is condensed into a liquid working fluid, and an outlet pipe (outlet channel) 150 formed downstream of the spiral channel 141 in the direction of working fluid flow to discharge the condensed working fluid. The spiral channel 141 and the outlet pipe 150 are each partitioned as separate channels. The spiral channel 141 constitutes a channel through which the working fluid flows in the other axial direction, while the outlet pipe 150 constitutes a channel through which the working fluid flows in one axial direction.

[0031] The helical channel 141 extends spirally along the heat dissipation outer peripheral wall 135 of the heat dissipation casing 130. Specifically, the helical channel 141 is composed of the heat dissipation casing 130 (ring end wall 131, heat dissipation outer peripheral wall 135, and heat dissipation base end wall 137) as described above, an inner peripheral wall 142 formed radially inward from the heat dissipation outer peripheral wall 135, and a helical plate 145 formed between the heat dissipation outer peripheral wall 135 and the inner peripheral wall 142.

[0032] The inner circumferential wall 142 extends in the other axial direction from the inner circumferential edge of the ring end wall 131 and is connected to the heat dissipation base end wall 137. This inner circumferential wall 142 divides the internal space of the heat dissipation casing 130 into a cylindrical inner space 147 radially inward and a cylindrical outer space 148 radially outward. The helical plate 145 extends radially between the heat dissipation outer circumferential wall 135 and the inner circumferential wall 142 and is connected to each of them. The helical plate 145 also extends spirally in the circumferential direction from the starting end 146 connected to the ring end wall 131 to the heat dissipation base end wall 137. The end of the helical plate 145 (not shown) is connected to the heat dissipation base end wall 137.

[0033] With this configuration, the cylindrical outer space 148 of the heat dissipation casing 130 is divided into multiple stages in the axial direction by the helical plates 145, thereby forming a helical flow path 141. More specifically, the uppermost stage of the helical flow path 141 is divided by the ring end wall 131 and the helical plate 145. The lowermost stage of the helical flow path 141 is divided by the helical plate 145 and the heat dissipation base end wall 137. The portion located between the uppermost and lowermost stages is divided by two helical plates 145 that are adjacent to each other in the axial direction. The end of the lowermost stage of the helical flow path 141 is closed by a closing plate 149 arranged to intersect in the circumferential direction, as shown in Figure 5(c).

[0034] As shown in Figure 6, the outlet liquid pipe 150 has a connecting channel section 151 that communicates with the downstreammost stage of the spiral channel 141, and a straight channel section 155 that continues in an L-shape downstream of the connecting channel section 151. As shown in Figure 5(c), the connecting channel section 151 is connected to the inner circumferential wall 142 and extends from this inner circumferential wall 142 to the radial center. The connecting channel section 151 communicates with the spiral channel 141 via an outlet opening 152 formed in the inner circumferential wall 142 at the downstreammost stage of the spiral channel 141. This outlet opening 152 is formed in front of the closing plate 149 in the spiral channel 141.

[0035] As shown in Figure 6, the straight channel section 155 communicates downstream of the connecting channel section 151 in the direction of working fluid flow, and extends axially from the connecting channel section 151 at its radial center. That is, the straight channel section 155 extends axially from the heat dissipation base end wall 137 side through the inner space 147 of the heat dissipation casing 130, and penetrates the radially inner side of the ring end wall 131. This straight channel section 155 is radially spaced apart from the helical channel section 141, and one end of it protrudes outside the inner space 147. As shown in Figure 2, one end of the straight channel section 155 is connected to the reservoir 180.

[0036] With this configuration, as shown in Figure 5(c), when the working fluid liquefied in the helical channel 141 flows to the downstream end of the helical channel 141 (see arrow F51), it flows into the outlet liquid pipe 150 through the outlet opening 152 (see arrow F52). The working fluid then flows radially inward through the connecting channel section 151 of the outlet liquid pipe 150, changes direction, and flows axially in one direction through the straight channel section 155.

[0037] <Configuration of the Circulation Section> As shown in Figure 2, the circulation section 103 has a hollow tubular circulation section casing 160, and a steam pipe 170 and a reservoir 180 housed in the circulation section casing 160. The circulation section casing 160 is a hollow tubular member, with one end closed and the other end open. The circulation section casing 160 has a disc-shaped partition wall 161 at one end in the axial direction, and an intermediate outer peripheral wall 165 extending axially from the outer peripheral edge of the partition wall 161.

[0038] The partition wall 161 is disc-shaped with a central hole 163 formed therein, and the central hole 163 communicates with the wick's central hole 123 while in contact with the other end face 122 of the wick 120. The partition wall 161 also has a steam pipe inlet 162 that opens radially away from the central hole 163, and this steam pipe inlet 162 communicates with the discharge groove 127 of the wick 120.

[0039] The intermediate outer peripheral wall 165 has an annular cross-sectional shape perpendicular to the axial direction and extends in the axial direction. The other axial end 167 of the intermediate outer peripheral wall 165 is formed to follow the inclination and step of the ring end wall 131 of the heat dissipation casing 130 and is connected to one end 136 of the heat dissipation outer peripheral wall 135. Also, one end 166 of the intermediate outer peripheral wall 165 is connected to the other end 116 of the heat receiving outer peripheral wall 115. In other words, the intermediate outer peripheral wall 165, the heat receiving outer peripheral wall 115, and the heat dissipation outer peripheral wall 135 are continuous in the axial direction. With this configuration, the heat receiving casing 160 is connected to one axial end 168 of the circulation casing 160, and the heat dissipation casing 130 is connected to the other end 169. Thus, the heat receiving section casing 110, the circulation section casing 160, and the heat dissipation section casing 130 are aligned in a straight line with their respective pipe axis directions (first direction, second direction, and third direction) aligned in the same direction.

[0040] Figure 7(a) is a perspective view of the steam pipe 170, and (b) is a perspective view of the reservoir 180. Figure 8(a) is a cross-sectional view taken from the VIIIa-VIIIa plane of Figure 2, and (b) is a cross-sectional view taken from the VIIIb-VIIIb plane of Figure 2. As shown in Figure 7(a), the steam pipe 170 is a hollow member that extends in the axial direction and has a fan-shaped cross-sectional shape perpendicular to the axial direction. Both ends of the steam pipe 170 in the axial direction are open. To further explain, the steam pipe 170 has a steam pipe inlet 172 at one end in the axial direction and a steam pipe outlet 174 at the other end in the axial direction. Also, as shown in Figure 2, the steam pipe inlet 172 of the steam pipe 170 is connected to the steam pipe inlet 162 of the bulkhead 161, and the steam pipe outlet 174 is connected to the steam pipe outlet 134 of the ring end wall 131. As shown in Figures 8(a) and (b), the steam pipe 170 is positioned adjacent to the intermediate outer wall 165, and its circumferentially long curved surface is in contact with the intermediate outer wall 165.

[0041] The reservoir 180 is a cylindrical member extending in the axial direction. As shown in Figures 8(a) and (b), the reservoir 180 has a D-shaped cross-section perpendicular to the axial direction and extends in the axial direction. More specifically, the reservoir 180 is composed of a reservoir end wall 181 formed in a D-shape in plan view at one end in the axial direction, a reservoir other end wall 182 formed in a D-shape in plan view at the other end in the axial direction, a flat reservoir rectangular plate 183 spanning between the reservoir end wall 181 and the reservoir other end wall 182, and an intermediate outer peripheral wall 165 of the circulation casing 160. More specifically, the arc-shaped edge 181a of the reservoir end wall 181 and the arc-shaped edge 182a of the reservoir other end wall 182 are connected to the intermediate outer peripheral wall 165 of the circulation casing 160, respectively. Furthermore, the outer edge 183a of the reservoir rectangular plate 183 is connected to the straight edge 181b of the reservoir one end wall 181, the straight edge 182b of the reservoir other end wall 182, and the intermediate outer peripheral wall 165 of the circulation casing 160. This ensures that the fluid storage chamber is liquid-tight.

[0042] One reservoir end wall 181 has a liquid supply pipe 185 that communicates with the storage chamber of the reservoir 180 and supplies working fluid to the wick 120. The liquid supply pipe 185 extends axially outward from one end face of the one reservoir end wall 181 at the radial center, and is connected to the central hole 163 (see FIG. 2) of the partition wall 161. That is, the liquid supply pipe 185 allows communication between the storage chamber of the reservoir 180 and the wick central hole 123 via the central hole 163. The other reservoir end wall 182 is formed with a discharged liquid pipe connection port 187 to which the discharged liquid pipe 150 of the condensing section 140 is connected, and provides communication between the storage chamber of the reservoir 180 and the condensing section 140.

[0043] As shown in FIG. 8(b), the reservoir 180 is disposed spaced apart from the steam pipe 170. The cross-sectional area of the reservoir 180 in a cross-section orthogonal to the axial direction is formed larger than the cross-sectional area of the steam pipe 170. To further explain, the cross-sectional area of the reservoir 180 in the cross-section orthogonal to the axial direction accounts for more than half of the cross-sectional area of the accommodation space 164. Furthermore, as shown in FIG. 2, the reservoir 180 extends long in the axial direction from the vicinity of one end 166 to the vicinity of the other end 167 of the intermediate outer peripheral wall 165.

[0044] As described above, in the circulation section 103, the steam pipe 170 and the reservoir 180 are accommodated in one accommodation space 164 defined by the circulation section casing 160. The accommodation space 164 communicates with the inner space 147 of the heat radiating section 102 and is formed airtight. Then, the accommodation space 164 is evacuated together with the inner space 147 of the heat radiating section 102 to form a vacuum heat insulating layer (heat insulating section). As described above, in the loop heat pipe 100, the heat receiving section 101, the circulation section 103, and the heat radiating section 102 are respectively partitioned, and the heat receiving section 101 and the heat radiating section 102 are isolated from each other via the circulation section 103.

[0045] <Configuration of Secondary Wick> FIG. 9 is a perspective view of a secondary wick 190. Next, the secondary wick 190 will be described with reference to FIG. 2 and FIG. 9. As shown in FIG. 2, the secondary wick 190 is a hollow member extending in the axial direction. One axial side of the secondary wick 190 is inserted into the interior of the wick 120, and the other axial side thereof is inserted into the interior of the reservoir 180.

[0046] Like the wick 120, the secondary wick 190 is a member made of porous metal. The secondary wick 190 has a larger effective pore diameter (or average pore diameter) than the wick 120, and is formed to have, for example, a pore diameter of 1 μm to 100 μm. Further, the secondary wick 190 is formed to have a smaller wall thickness than the wick 120.

[0047] As shown in FIG. 9, the secondary wick 190 has an immersed part 191 arranged on the reservoir one end wall 181 side in the storage chamber of the reservoir 180, and a liquid transport part 195 that transports working fluid from the immersed part 191 to the wick central hole 123.

[0048] The immersed part 191 is formed to have a D-shaped cross-sectional shape in the axial direction so as to conform to the inner surface shape of the reservoir 180 on the reservoir one end wall 181 side (see FIG. 8(b)). At least a part of the immersed part 191 is formed to be located below the liquid level of the working fluid stored in the reservoir 180. The liquid transport part 195 is formed in a hollow tubular shape, and extends from one end of the immersed part 191 to one side in the axial direction. The liquid transport part 195 has a smaller radial dimension than the immersed part 191. As shown in FIG. 2, the liquid transport part 195 is inserted through the liquid supply pipe 185, extends to one end of the wick central hole 123, and is arranged so as to be in contact with the inner circumferential surface of the wick central hole 123.

[0049] With this configuration, the working fluid in the liquid phase within the reservoir 180 permeates the immersion section 191 and moves to the liquid transport section 195 by capillary force. The working fluid then moves to the wick 120, which is in contact with the liquid transport section 195. In other words, the secondary wick 190 facilitates the flow of working fluid to the wick 120. This prevents interruptions in the supply of working fluid to the wick 120.

[0050] <Operation of each part of the loop heat pipe> Figure 10 is an axial cross-sectional view of the heat receiving section 101 and the circulation section 103. Figure 11 is an axial cross-sectional view of the heat dissipation section 102. Next, the operation of each part of the loop heat pipe 100 will be explained with reference to Figures 10 and 11. First, as shown in Figure 10, the liquid phase working fluid stored in the reservoir 180 permeates from the immersion section 191 of the secondary wick 190 to the liquid transport section 195 by capillary force (see arrow F11). A portion of the working fluid that has moved to the liquid transport section 195 (see arrow F12) moves from the inner circumferential surface of the wick central hole 123 toward the outer circumferential section 124, and reaches the contact interface (contact section) where the outer circumferential section 124 and the heat receiving outer circumferential wall 115 come into contact (see arrow F21). Then, the working fluid vaporizes due to the heat received by the heat receiving outer circumferential wall 115 from the heating element RC (see arrow C11), and absorbs latent heat of vaporization from the surroundings.

[0051] Furthermore, the remaining portion of the working fluid that has moved to the liquid transport section 195 moves from one end of the wick central hole 123 toward the one end face 121, reaching the contact interface where the one end face 121 and the heat-receiving one end wall 111 come into contact (see arrow F22). The heat absorbed by the heat-receiving one end wall 111 from the heat-generating element RC (see arrow C12) causes the working fluid to vaporize, absorbing the latent heat of vaporization. In this way, the heat-generating element RC is cooled by the evaporation of the working fluid.

[0052] Next, the working fluid vaporized in the wick 120 flows out into the long groove 125, then flows in the other axial direction and is collected in the converging groove 126 (see arrow F31). It then flows circumferentially through the converging groove 126 (see arrow F32) and is discharged from the discharge groove 127 to the steam pipe inlet 162 (see arrow F33). The gaseous working fluid that flows into the steam pipe 170 from the steam pipe inlet 172 connected to the steam pipe inlet 162 flows in the other axial direction within the steam pipe 170 and heads towards the steam pipe outlet 174 (see arrow F41).

[0053] As shown in Figure 11, the working fluid that flows into the spiral channel 141 from the steam pipe outlet 134 connected to the steam pipe outlet 174 flows circumferentially toward the heat dissipation base end wall 137. As it flows through the long, spirally formed spiral channel 141 (see arrow F51), the gaseous working fluid dissipates heat to the outside and condenses (see arrow C21). At this time, because the working fluid flows spirally, heat is released uniformly across the entire heat dissipation outer peripheral wall 135 without being concentrated in a part of the circumferential direction. Furthermore, since a part of the spiral channel 141 is composed of the heat dissipation outer peripheral wall 135 of the heat dissipation casing 130, the heat of the working fluid is released to the outside more efficiently.

[0054] The working fluid, which has condensed and liquefied in the spiral channel 141, flows into the outlet pipe 150 through the outlet opening 152 in the inner circumferential wall 142 (see Figure 2) when it reaches the downstream end of the spiral channel 141 (see arrow F52 in Figure 5(c)). The working fluid that has flowed into the outlet pipe 150 flows radially inward through the connecting channel section 151, then changes direction in an L-shape and flows axially in one direction through the straight channel section 155 (see arrow F53). At this time, the spiral channel 141 and the straight channel section 155 of the outlet pipe 150 are spaced apart, and a vacuum insulation layer is formed between them, so the working fluid in the straight channel section 155 of the outlet pipe 150 is not easily heated by the working fluid in the gas phase in the spiral channel 141.

[0055] The working fluid that flows through the outlet pipe 150 in one axial direction flows out from the outlet pipe connection port 187 into the storage chamber of the reservoir 180 and is stored again (see arrow F54). At this time, the reservoir 180 and the steam pipe 170 are spaced apart, and a vacuum layer forms between them for insulation, so the working fluid in the liquid phase of the reservoir 180 is less likely to be heated by the working fluid in the gas phase of the steam pipe 170.

[0056] As explained above, in the loop heat pipe 100, the circulation casing 160 is disposed between the heat receiving casing 110 and the heat dissipation casing 130, thus separating the heat receiving casing 110 and the heat dissipation casing 130. This makes it difficult for the heat receiving section 101 and the heat dissipation section 102 to interfere with each other's heat. Furthermore, in the circulation section 103 that circulates the working fluid between the heat receiving section 101 and the heat dissipation section 102, a steam pipe 170 is secured independently as a flow path for the working fluid from the heat receiving section 101 to the heat dissipation section 102, and a reservoir 180 is secured independently as a flow path for the working fluid from the heat dissipation section 102 to the heat receiving section 101. This allows the working fluid to circulate smoothly between the heat receiving section 101 and the heat dissipation section 102, which are spaced apart from each other. Therefore, heat can be transferred more reliably while suppressing energy loss between the heat receiving section 101 and the heat dissipation section 102, thereby improving heat transfer performance. Furthermore, since the heat receiving casing 110 is connected to one axial end 168 of the circulation casing 160 and the heat dissipation casing 130 is connected to the other end 169, the heat receiving section 101 and the heat dissipation section 102 can be sufficiently spaced apart in the axial direction.

[0057] Furthermore, since the steam pipe 170 and reservoir 180 are housed in one of the housing spaces 164 of the circulation casing 160, the overall configuration of the loop heat pipe 100 can be made compact. Also, since the steam pipe 170 and reservoir 180 are spaced apart from each other, and the steam pipe 170 and reservoir 180 are insulated by the vacuum insulation layer of the housing space 164, the liquid phase working fluid in the reservoir 180 is less likely to be heated by the gas phase working fluid flowing through the steam pipe 170. As a result, a lower temperature working fluid is supplied to the heat receiving section 101, allowing more heat to be removed from the heat generating element RC. Therefore, the heat transfer performance can be improved.

[0058] Furthermore, since the heat receiving casing 110, the circulation casing 160, and the heat dissipation casing 130 are arranged in the axial direction and in a straight line, the heat receiving section 101 and the heat dissipation section 102 can be sufficiently spaced apart, and the heat receiving surface and heat dissipation surface can be made longer in the axial direction. In addition, since the condensing section 140 has a helical flow path 141, a long heat dissipation surface can be secured and there is no bias in the circumferential direction, making it easier to condense the working fluid. Also, since the outlet liquid pipe 150 extends in the inner space 147 radially inside the helical flow path 141, the condensing section 140 can be made compact. In other words, by making the condensing section 140 more compact and securing a larger space for the heat dissipation surface and the helical flow path 141, the heat dissipation performance can be greatly improved. Furthermore, since the cross-sectional area of ​​the reservoir 180 is larger than the cross-sectional area of ​​the steam pipe 170 in a cross-section perpendicular to the axial direction, sufficient capacity of the reservoir 180 and the amount of working fluid can be secured.

[0059] In this configuration, the loop heat pipe 100 is connected to the heat receiving casing 110, the circulation casing 160, and the heat dissipation casing 130 using hollow tubular members. However, it may also be configured to use a single, integrated member from the outset. Alternatively, the heat receiving casing 110, the circulation casing 160, and the heat dissipation casing 130 may be further divided and connected.

[0060] Furthermore, although the loop heat pipe 100 uses an annular cross-sectional shape perpendicular to the axial direction, it may also have an elliptical, triangular, square, or hexagonal cross-sectional shape. Also, the shapes of the heat receiving casing 110, the circulation casing 160, and the heat dissipation casing 130 may differ from each other, and their diameters may also differ. In addition, the shape of a part of the heat receiving casing 110, the circulation casing 160, and the heat dissipation casing 130 may differ from the other parts. The cross-sectional shapes of the steam pipe 170 and the reservoir 180 can also be changed as appropriate. Also, part or all of the heat receiving casing 110, the circulation casing 160, and the heat dissipation casing 130 do not have to be elongated in one direction.

[0061] Furthermore, the cross-sectional shape of the wick 120 can be appropriately changed according to the cross-sectional shape of the loop heat pipe 100. In addition, the shape and number of the long grooves 125, aggregation grooves 126, and discharge grooves 127 on the outer circumference 124 of the wick 120 can also be appropriately changed. In addition, although the heat receiving section 101 is configured with grooves formed in the wick 120 to serve as flow paths for the working fluid, grooves may also be formed in the heat receiving section casing 110. Also, although the spiral flow path 141 is configured to be partitioned by the heat dissipation section casing 130 (ring end wall 131, heat dissipation outer wall 135, and heat dissipation base end wall 137), the inner circumferential wall 142, and the spiral plate 145, the ring end wall 131, the spiral plate 145, and the inner circumferential wall 142 may be omitted, and a spiral tube (not shown) may be housed in the heat dissipation section casing 130.

[0062] Furthermore, the loop heat pipe 100 is configured to have a secondary wick 190, taking into consideration usage scenarios where the heat receiving section 101 is positioned upward in the direction of gravity and the heat dissipation section 102 is positioned downward in the direction of gravity. However, in usage scenarios where the heat receiving section 101 is positioned lower than the heat dissipation section 102 in the direction of gravity (bottom heat) or where the axial direction of the loop heat pipe 100 is horizontal, the secondary wick 190 may be omitted. Also, although the housing space 164 of the circulation section casing 160 is made of a vacuum insulation layer, it is not necessarily required to be a vacuum, and an air layer or the like may be used. Alternatively, for example, a ceramic fiber (inorganic material) may be used to form the insulation layer. In other words, a configuration in which a so-called insulation material is provided in the housing space 164 may be used. In addition, although porous metal was used for the wick 120 and secondary wick 190, they are not limited to porous metal and may be formed from porous resins such as polytetrafluoroethylene (PTFE), porous ceramics, porous glass, porous fibers, etc.

[0063] <Nuclear Reactor> Figure 12(a) is a diagram illustrating a nuclear reactor 1 equipped with a loop heat pipe 10, (b) is a cross-sectional view of the reactor core 2 cut along the XIIb-XIIb plane of (a), and (c) is an enlarged view of XIIc of (b). Next, the nuclear reactor 1 will be explained with reference to Figures 12(a) to (c).

[0064] Reactor 1 is a relatively small reactor with a thermal output of 20 MWth or less. As shown in Figure 12(a), reactor 1 comprises a core 2 containing nuclear fuel, a plurality of loop heat pipes 10 that transfer heat generated by the nuclear fission reaction of the nuclear fuel to the outside of the core 2, an intermediate heat exchanger 3 that exchanges heat with the plurality of loop heat pipes 10, and a pressure vessel 4 that shields the core 2 from radiation.

[0065] The reactor core 2 comprises a core body 21 made of alternating layers of high thermal conductors and fuel plates, a reflector 23 that reflects neutrons emitted from the core body 21, a plurality of control drums 25 that control the output during normal operation (see Figure 12(b)), and a plurality of control rods 26 that control the output in emergencies. The core body 21 is formed in a cylindrical shape and extends in the axial direction of the core 2, and has a plurality of insertion holes 27, 28 into which the control rods 26 and loop heat pipes 10 are inserted. Hereinafter, the axial direction of the core 2 will be referred to as the core axial direction, the radial direction of the core 2 as the core radial direction, and the circumferential direction of the core 2 as the core circumferential direction.

[0066] The reflector 23 is made of, for example, graphite and is installed to surround the reactor core body 21. The reflector 23 has multiple drum holes 24 that extend in the direction of the reactor core axis and into which control drums 25 are inserted. Each of the control drums 25 is fitted with a neutron absorber, and the reactivity of the nuclear fuel is controlled by the rotation angle of the drum holes 24. These control drums 25 are each inserted into the drum holes 24 of the reflector 23 and are arranged concentrically. In the illustrated example, 12 control drums 25 are installed.

[0067] Multiple control rods 26 are made of a neutron-absorbing material, and the length to which they are inserted controls the nuclear reaction in the reactor core 2. Each of these control rods 26 is inserted into an insertion hole 27 in the reactor core body 21 and is arranged concentrically. More specifically, as shown in Figure 12(c), one control rod 26 is positioned at the center of the reactor core body 21 in the radial direction of the reactor core, while multiple control rods 26 are arranged to form control rod annular rows 26A, 26B, and 26C. Each of the control rod annular rows 26A, 26B, and 26C consists of eight control rods 26 arranged in a ring shape in the circumferential direction of the reactor core. These control rod annular rows 26A, 26B, and 26C are arranged in this order from the center in the radial direction of the reactor core and are concentric.

[0068] As shown in Figure 12(a), the loop heat pipe 10 is configured to be longer in the axial direction than the loop heat pipe 100 shown in Figure 1, etc., and has a heat receiving section 101, a heat dissipation section 102, and a circulation section 103, similar to the loop heat pipe 100, and its internal structure is the same as that of the loop heat pipe 100. In the multiple loop heat pipes 10, each heat receiving section 101 is inserted into the insertion hole 28 of the reactor core 2, while each heat dissipation section 102 is inserted into the intermediate heat exchanger 3. The circulation section 103 is located between the reactor core 2 and the intermediate heat exchanger 3. When the loop heat pipe 10 is installed with the axial direction horizontal, it is desirable to install it so that the steam pipe 170 is located below and the reservoir 180 is located above, from the viewpoint of supplying working fluid to the wick 120 (see Figure 2).

[0069] As shown in Figure 12(c), these multiple loop heat pipes 10 are arranged concentrically and configured to form pipe ring rows 10A, 10B, and 10C. Each of the pipe ring rows 10A, 10B, and 10C is composed of multiple loop heat pipes 10 arranged in a ring shape in the circumferential direction of the reactor core. These pipe ring rows 10A, 10B, and 10C are arranged in this order from the center in the radial direction of the reactor core and are concentric. Furthermore, pipe ring row 10A is composed of four loop heat pipes 10, and pipe ring rows 10B and 10C are each composed of eight loop heat pipes 10.

[0070] Multiple loop heat pipes 10 are arranged in the reactor core body 21 so as to be positioned between the control rods 26. Specifically, the pipe ring row 10A is arranged in the radial direction of the reactor core between the control rods 26 at the center of the reactor core 2 and the control rod ring row 26A. Furthermore, the pipe ring row 10B and the control rod ring row 26A are formed at the same position in the radial direction of the reactor core, and the control rods 26 and loop heat pipes 10 are arranged alternately in the circumferential direction of the reactor core. Similarly, the pipe ring row 10C and the control rod ring row 26B are formed at the same position in the radial direction of the reactor core, and the control rods 26 and loop heat pipes 10 are arranged alternately in the circumferential direction of the reactor core.

[0071] As shown in Figure 12(a), the intermediate heat exchanger 3 is connected to an external power generation facility E (heat utilization device, such as a steam turbine power plant) via piping 31, and is configured to circulate refrigerant between it and the power generation facility E (see arrows C3 and C4). The intermediate heat exchanger 3 releases heat from the heat dissipation section 102 of the loop heat pipe 10 to the refrigerant in the piping 31.

[0072] <Operation of the Nuclear Reactor> Next, the operation of the nuclear reactor 1 will be explained. When a nuclear reaction occurs in the core 2 and heat is generated, this heat is received by the heat receiving sections 101 of the multiple loop heat pipes 10 inserted into the core 2. The heat received by the heat receiving section 101 of each loop heat pipe 10 is transmitted via the working fluid to the circulation section 103 and then to the heat dissipation section 102, respectively, as described above. Then, heat is released to the refrigerant from each heat dissipation section 102 inserted into the intermediate heat exchanger 3. Finally, the heat released to the refrigerant is transmitted to the power generation equipment E, and electricity is generated by this heat.

[0073] As explained above, since this reactor 1 is equipped with a loop heat pipe 10, the heat from the reactor core 2 can be efficiently transferred to the intermediate heat exchanger 3 and, consequently, to the external power generation equipment E. Therefore, the power output of the power generation equipment can be improved. In addition, since the outer heat receiving wall 115 and the heat receiving end wall 111 of the heat receiving section casing 110 are heat receiving surfaces that receive heat from the reactor core 2, a large amount of heat can be received from the reactor core 2, and the reactor core 2 can be efficiently cooled.

[0074] Furthermore, even if the loop heat pipe 10 is configured to be relatively thin, high heat transfer performance can be ensured, allowing the reactor 1 to be configured to be relatively small. To further explain, the loop heat pipe 10 can be easily installed even in the narrow space between the control rods 26. In other words, by configuring the loop heat pipe 10 to be thin, the reactor 1 can be made compact. In this configuration, the reactor 1 is configured to supply heat to the power generation equipment E via the intermediate heat exchanger 3, but power generation may be performed directly using a device with thermoelectric conversion elements by omitting the intermediate heat exchanger. Also, the pressure vessel 4 may be omitted, especially in outer space.

[0075] <Modification 1> Figure 13 is a diagram illustrating Modification 1. Figures 13(a) to (c) correspond to Figure 8(b) which shows the above embodiment. In the description from Figure 13 onward, the same reference numerals are used for components identical to those in the above embodiment, and their detailed descriptions may be omitted. Next, Modification 1 will be described with reference to Figures 13(a) to (c).

[0076] In the above embodiment, a portion of the reservoir 180 is formed by the intermediate outer peripheral wall 165 of the circulation casing 160, while the steam pipe 170 is positioned adjacent to the intermediate outer peripheral wall 165. However, the embodiment is not limited to this. For example, as shown in Figure 13(a), a curved plate 188 may be used instead of the intermediate outer peripheral wall 165 to form the reservoir 180A. That is, the reservoir 180A is composed of a reservoir one-end wall 181, a reservoir other-end wall 182, a reservoir rectangular plate 183, and a curved plate 188 as shown in Figure 7.

[0077] The curved plate 188 is a separate component from the intermediate outer peripheral wall 165 and is formed in the shape of a half-pipe. Specifically, the curved plate 188 extends axially from the arc-shaped edge 181a of the reservoir end wall 181 shown in Figure 7 to the arc-shaped edge 182a of the reservoir end wall 182, and its axial cross-sectional contour is formed in an arc shape. The reservoir 180A is constructed by replacing the intermediate outer peripheral wall 165 shown in Figure 7 with the curved plate 188. This configuration also provides the same effects as the embodiment described above, and since a vacuum insulation layer can be created between the intermediate outer peripheral wall 165 and the reservoir 180A, it is possible to suppress the heat absorption of the working fluid in the reservoir 180A from the outside.

[0078] Similarly, for example, the steam pipe 170A shown in Figure 13(a) may be arranged spaced apart from the intermediate outer wall 165. This configuration suppresses heat leakage from the working fluid flowing through the steam pipe 170A to the outside. Therefore, the heat received from the heat-generating element RC (see Figure 1) can be reliably transferred by the heat dissipation section 102.

[0079] Furthermore, as shown in Figure 13(b), a curved plate 189 that is more curved than the curved plate 188 may be used, for example. By configuring it in this way, a large vacuum insulation layer can be secured between the reservoir 180B and the intermediate outer wall 165. Also, as shown in Figure 13(c), a portion of the steam pipe 170 may be made of the intermediate outer wall 165, similar to the reservoir 180. By configuring it in this way, it becomes easier to secure a large gap between the reservoir 180 and the steam pipe 170, and the transfer of heat from the working fluid of the steam pipe 170B to the working fluid of the reservoir 180 can be further suppressed. From another perspective, even if the cross-sectional area of ​​the steam pipe 170B and the cross-sectional area (capacity) of the reservoir 180 are made large, a sufficient gap can be secured between the steam pipe 170B and the reservoir 180.

[0080] <Modification 2> Figures 14(a) to (d) are diagrams illustrating Modification 2. (a) is a diagram corresponding to Figure 2 showing the above embodiment, (b) is a cross-sectional view of (a) cut along the XIVb-XIVb plane, (c) is a cross-sectional view of (a) cut along the XIVc-XIVc plane, and (d) is a cross-sectional view of (a) cut along the XIVd-XIVd plane. Next, Modification 2 will be explained with reference to Figures 14(a) to (d).

[0081] In the above embodiment, the heat receiving casing 110, the circulation casing 160, and the heat dissipation casing 130 are formed with the same diameter, but the embodiment is not limited to this. For example, as in the loop heat pipe 200 shown in Figure 14(a), the circulation casing 260 and the heat dissipation casing 230 may be formed with a larger outer diameter than the heat receiving casing 110.

[0082] The circulation section casing 260 has a larger outer diameter than the heat receiving section casing 110, and the cross-sectional area of ​​the circulation section casing 260 perpendicular to the axial direction is larger than that of the heat receiving section casing 110. The circulation section casing 260 has a partition wall 261 and an intermediate outer peripheral wall 265, which have a larger outer diameter than the partition wall 161 of the above embodiment.

[0083] Furthermore, as shown in Figure 14(b), the circulation casing 260 has its central axis Q eccentric with respect to the central axis P of the heat receiving casing 110. Comparing the heat receiving outer peripheral wall 115 and the intermediate outer peripheral wall 265 of the heat receiving casing 110, the intermediate outer peripheral wall 265 protrudes significantly radially outward from the heat receiving outer peripheral wall 115. That is, as shown in Figures 14(a) and (c), the circulation casing 260 has a larger housing space 264 than the housing space 164 of the above embodiment (see Figure 2), and accommodates a large-capacity reservoir 280.

[0084] As shown in Figures 14(a) and (d), the heat dissipation casing 230 is formed coaxially with the circulation casing 260 and has a heat dissipation outer peripheral wall 235, a ring end wall 231, and a heat dissipation base end wall 237, which have a larger outer diameter than the heat receiving casing 110. A spiral flow path 241 of the condensation section 240 is arranged in the heat dissipation casing 230 along the heat dissipation outer peripheral wall 235.

[0085] This configuration allows the large-capacity reservoir 280 to accommodate a large amount of working fluid. Furthermore, the helical flow path 241 can be formed to be longer in a helical shape, and a larger heat dissipation surface can be secured. These improvements further enhance the heat transfer performance of the loop heat pipe 200. The circulation casing 260 and the heat dissipation casing 230 may be formed with different outer diameters. Additionally, the circulation casing 260 and the heat dissipation casing 230 may be formed with smaller outer diameters than the heat receiving casing 110. This allows the loop heat pipe 200 to be installed in a way that flexibly adapts to the surrounding environment of the heat source.

[0086] <Modification 3> Figure 15 is a diagram illustrating Modification 3. Note that Figure 15 corresponds to Figure 2, which shows the above embodiment. Next, Modification 3 will be described with reference to Figure 15. In the above embodiment, the circulation section casing 160 was configured to be rigid (hard and inflexible), but this is not the case. For example, the circulation section casing 360 may be made flexible and deformable, as in the loop heat pipe 300 shown in Figure 15.

[0087] The circulation casing 360 includes a bellows-shaped intermediate outer peripheral wall 365, a steam pipe 370 made of a flexible pipe member, and a reservoir 380 including a bellows-shaped rectangular plate 383. The reservoir 380 is configured such that one end wall 181 and the other end wall 182 of the reservoir are connected to the intermediate outer peripheral wall 365 and the rectangular plate 383. The outlet liquid pipe connection port 187 of the reservoir 380 and the outlet liquid pipe 150 of the heat dissipation section 102 are connected via a flexible joint 389. On the other hand, the liquid supply pipe 385 is made of a flexible pipe member and is connected to the central hole 163 of the partition wall 161. The secondary wick 390 has a narrow immersion portion 391 and is arranged so that at least a part of it is located below the liquid level of the working fluid stored in the reservoir 380.

[0088] In this way, the reservoir 380 and steam pipe 370 are deformable in accordance with the deformation of the circulation casing 360. With this configuration, the circulation casing 360 is flexible and deformable, so it can flexibly accommodate various positional relationships between the heat source and external equipment. This improves the ease of application and installation of the loop heat pipe 300.

[0089] <Modification 4> Figures 16(a) to (e) are schematic diagrams illustrating Modification 4. Next, Modification 4 will be explained with reference to Figures 16(a) to (e).

[0090] In the above embodiment, the heat receiving casing 110, the circulation casing 160, and the heat dissipation casing 130 are configured in a straight line so that their respective pipe axis directions (longitudinal direction) are aligned in the same direction, but the embodiment is not limited to this. For example, as shown in Figure 16(a), the heat receiving casing 110 and the heat dissipation casing 130 are aligned in the same direction, but the pipe axis direction of the circulation casing 160 may be arranged at an angle to the pipe axis directions of the heat receiving casing 110 and the heat dissipation casing 130. Also, as shown in Figure 16(b), the heat receiving casing 110 and the circulation casing 160 are the same as in the loop heat pipe 400A, but the pipe axis direction of the heat dissipation casing 130 may be arranged perpendicular to the pipe axis direction of the heat receiving casing 110.

[0091] Furthermore, as shown in Figure 16(c), the loop heat pipe 400C may be configured such that the axial directions of the heat receiving casing 110 and the heat dissipation casing 130 are perpendicular to the axial direction of the circulation casing 160, and the heat receiving end wall 111 of the heat receiving casing 110 and the heat dissipation base end wall 137 of the heat dissipation casing 130 are oriented in the same direction. Alternatively, as shown in Figure 16(d), the loop heat pipe 400D may be configured such that the axial directions of the heat receiving casing 110 and the heat dissipation casing 130 are perpendicular to the axial direction of the circulation casing 160, and the heat receiving end wall 111 of the heat receiving casing 110 and the heat dissipation base end wall 137 of the heat dissipation casing 130 are oriented in opposite directions.

[0092] Furthermore, as shown in Figure 16(e) for the loop heat pipe 400E, the heat receiving casing 110 and the heat dissipation casing 130 may be arranged so that their axial directions are perpendicular to the axial direction of the circulation casing 160, and the heat receiving end wall 111 of the heat receiving casing 110 may be oriented in the same direction as the heat receiving casing 110 of the heat pipes 400D and 400E, while the heat dissipation base end wall 137 of the heat dissipation casing 130 may be oriented toward the front of the drawing (twist direction). As illustrated in the arrangement patterns in Figures 16(a) to (e), by arranging at least one of the heat receiving casing 110 and the heat dissipation casing 130 to extend in a direction different from the circulation casing 160, it is possible to flexibly accommodate various positional relationships between the heat utilization device and the heat source. This improves the ease of application and installation of the loop heat pipe.

[0093] Here, the apparatus in which the loop heat pipe 100, which is an example of a heat exchanger, is provided is not limited to the nuclear reactor described above. For example, the loop heat pipe 100 may be provided in various devices equipped with heat-generating components, such as electronic devices like personal computers and projectors, and transportation equipment like automobiles. Furthermore, the loop heat pipe 100 may be provided in a device that extracts heat from hot spring water or geothermal energy and supplies it to external utilization facilities.

[0094] All or part of the above embodiments, or modifications thereof, may also be described as follows, without limitation: <Note> (Note 1) A heat exchanger comprising: a heat receiving section that receives heat from the outside and evaporates a liquid-phase working fluid; a heat dissipation section that condenses a gaseous-phase working fluid that flows in from the heat receiving section and releases heat to the outside; and a circulation section that circulates the working fluid between the heat receiving section and the heat dissipation section, wherein the heat receiving section comprises an evaporator that evaporates the liquid-phase working fluid and a heat receiving section casing that houses the evaporator; the heat dissipation section comprises a condensing section that condenses the gaseous-phase working fluid and a heat dissipation section casing that houses the condensing section; and the circulation section comprises a steam pipe that allows the gaseous-phase working fluid discharged from the evaporator to flow out to the condensing section; a reservoir that stores the liquid-phase working fluid that flows in from the condensing section in an internal space and allows the working fluid in the internal space to flow out to the evaporator; and a circulation section casing that houses the steam pipe and the reservoir and is connected to the heat receiving section casing and the heat dissipation section casing. (Note 2) The heat exchanger according to Note 1, wherein the circulation casing extends in a first direction, the heat receiving casing is connected to one end in the first direction, and the heat dissipation casing is connected to the other end in the first direction. (Note 3) The heat exchanger according to Note 1 or 2, wherein the circulation casing houses the steam pipe and the reservoir in a single housing space. (Note 4) The heat exchanger according to any one of Notes 1 to 3, wherein the reservoir and the steam pipe are spaced apart from each other. (Note 5) The heat exchanger according to any one of Notes 1 to 4, wherein the circulation casing has an insulating material to insulate the reservoir and the steam pipe. (Note 6) The heat exchanger according to any one of Notes 1 to 5, wherein the circulation casing extends in a first direction, and in a cross section perpendicular to the first direction, the cross-sectional area of ​​the reservoir is formed to be larger than the cross-sectional area of ​​the steam pipe. (Note 7) The heat exchanger according to any one of Notes 1 to 6, wherein the circulation casing, the steam pipe, and the circulation casing are deformable.(Note 8) The heat exchanger according to any one of Notes 1 to 7, wherein the heat receiving casing, the circulation casing, and the heat dissipation casing are provided along one direction and arranged in a straight line. (Note 9) The heat exchanger according to any one of Notes 1 to 8, wherein at least one of the heat receiving casing and the heat dissipation casing extends in a direction different from that of the circulation casing. (Note 10) The heat exchanger according to any one of Notes 1 to 9, wherein the condensing section has a spiral channel extending spirally along the outer wall of the heat dissipation casing, and an outflow channel formed downstream of the spiral channel in the direction of the working fluid flow, extending radially inward of the spiral channel toward the circulation casing, and through which the working fluid flows toward the reservoir. (Note 11) The heat exchanger according to any one of Notes 1 to 10, wherein the circulation section casing extends in a first direction and the cross-sectional area perpendicular to the first direction is formed as a first cross-sectional area, the heat dissipation section casing extends in a second direction and the cross-sectional area perpendicular to the second direction is formed as a second cross-sectional area, the heat receiving section casing extends in a third direction and the cross-sectional area perpendicular to the third direction is formed as a third cross-sectional area, and at least one of the first cross-sectional area and the second cross-sectional area is formed to be larger than the third cross-sectional area.(Note 12) The apparatus comprises: a heat receiving section that receives heat from the outside and evaporates a liquid-phase working fluid; a heat dissipation section that condenses a gaseous working fluid that flows in from the heat receiving section and releases heat to the outside; and a circulation section that circulates the working fluid between the heat receiving section and the heat dissipation section, wherein the heat receiving section comprises an evaporator that evaporates the liquid-phase working fluid and a heat receiving section casing that houses the evaporator; the heat dissipation section comprises a condensing section that condenses the gaseous working fluid and a heat dissipation section casing that houses the condensing section; and the circulation section comprises a steam pipe that allows the gaseous working fluid discharged from the evaporator to flow out to the condensing section; and a reservoir that stores the liquid-phase working fluid that flows in from the condensing section in an internal space and allows the working fluid in the internal space to flow out to the evaporator. A heat exchanger comprising a circulating casing connected to a heat receiving casing and a heat dissipation casing, wherein the condensing section comprises a spiral channel extending spirally along the outer wall of the heat dissipation casing, and an outlet channel formed downstream of the spiral channel in the direction of the working fluid flow, extending toward the circulating casing at a position spaced apart from the spiral channel on the radially inward side of the spiral channel, and through which the working fluid flows toward the reservoir.(Note 13) The reactor comprises a core and a heat exchanger that releases heat received from the core to an external heat utilization device, the heat exchanger comprising: a heat receiving section that receives heat from the core and evaporates a liquid-phase working fluid; a heat dissipation section that condenses a gaseous working fluid flowing in from the heat receiving section and releases heat to the heat exchanger; and a circulation section that circulates the working fluid between the heat receiving section and the heat dissipation section, the heat receiving section comprising an evaporator that evaporates the liquid-phase working fluid and a heat receiving section casing that houses the evaporator, the heat dissipation section comprising a condensing section that condenses the gaseous working fluid and a heat dissipation section casing that houses the condensing section, the circulation section comprising: a steam pipe that allows the gaseous working fluid discharged from the evaporator to flow out to the condensing section; and a reservoir that stores the liquid-phase working fluid flowing in from the condensing section in an internal space and allows the working fluid in the internal space to flow out to the evaporator. A reactor having a circulation casing that houses the steam pipe and the reservoir and is connected to the heat receiving casing and the heat dissipation casing. (Note 14) The reactor according to any one of Notes 1 to 13, wherein the tip of the heat receiving casing is a heat receiving surface that receives heat from the reactor core.

[0095] Now, various embodiments and modifications have been described above, but these embodiments and modifications can of course be combined to form a single structure. To further explain, each embodiment, modification, and component described herein can be arbitrarily combined and applied as long as they are not mutually exclusive. For example, the structures of the heat receiving section 101, heat dissipation section 102, circulation section 103, wick 120, heat dissipation section casing 130, and condensation section 140 described above can be combined as appropriate. Furthermore, this disclosure is not limited in any way to the embodiments described above, and can be implemented in various forms without departing from the spirit of this disclosure.

[0096] 1...Reactor, 100...Loop heat pipe (heat exchanger), 101...Heat receiving section, 102...Heat dissipation section, 103...Circulation section, 110...Heat receiving section casing, 120...Wick (evaporator), 130...Heat dissipation section casing, 140...Condensing section, 141...Spiral flow path, 150...Outlet pipe (outlet flow path), 160...Circulation section casing, 170...Steam pipe, 180...Reservoir

Claims

1. A heat exchanger comprising: a heat receiving section that receives heat from the outside and evaporates a liquid-phase working fluid; a heat dissipation section that condenses a gaseous-phase working fluid that flows in from the heat receiving section and releases heat to the outside; and a circulation section that circulates the working fluid between the heat receiving section and the heat dissipation section, wherein the heat receiving section comprises an evaporator that evaporates the liquid-phase working fluid and a heat receiving section casing that houses the evaporator; the heat dissipation section comprises a condensing section that condenses the gaseous-phase working fluid and a heat dissipation section casing that houses the condensing section; and the circulation section comprises a steam pipe that allows the gaseous-phase working fluid discharged from the evaporator to flow out to the condensing section; a reservoir that stores the liquid-phase working fluid that flows in from the condensing section in an internal space and allows the working fluid in the internal space to flow out to the evaporator; and a circulation section casing that houses the steam pipe and the reservoir and is connected to the heat receiving section casing and the heat dissipation section casing.

2. The heat exchanger according to claim 1, wherein the circulation casing extends in a first direction, the heat receiving casing is connected to one end in the first direction, and the heat dissipation casing is connected to the other end in the first direction.

3. The heat exchanger according to claim 1 or 2, wherein the circulation casing houses the steam pipe and the reservoir in a single housing space.

4. The heat exchanger according to claim 1 or 2, wherein the reservoir and the steam pipe are spaced apart from each other.

5. The heat exchanger according to claim 4, wherein the circulation section casing has an insulating material for insulating the reservoir and the steam pipe.

6. The heat exchanger according to claim 1 or 2, wherein the circulation casing extends in a first direction, and in a cross section perpendicular to the first direction, the cross-sectional area of ​​the reservoir is formed to be larger than the cross-sectional area of ​​the steam pipe.

7. The heat exchanger according to claim 1 or 2, wherein the circulation casing, the steam pipe, and the circulation casing are deformable.

8. The heat exchanger according to claim 1 or 2, wherein the heat receiving casing, the circulation casing, and the heat dissipation casing are provided along one direction and are arranged in a straight line.

9. The heat exchanger according to claim 1 or 2, wherein at least one of the heat receiving casing and the heat dissipation casing extends in a direction different from that of the circulation casing.

10. The heat exchanger according to claim 1 or 2, wherein the condensing section comprises a helical channel extending spirally along the outer wall of the heat dissipation section casing, and an outlet channel formed downstream of the helical channel in the direction of the working fluid flow, extending radially inward of the helical channel toward the circulation section casing, and through which the working fluid flows toward the reservoir.

11. The heat exchanger according to claim 1 or 2, wherein the circulation section casing extends in a first direction and the cross-sectional area perpendicular to the first direction is formed as a first cross-sectional area, the heat dissipation section casing extends in a second direction and the cross-sectional area perpendicular to the second direction is formed as a second cross-sectional area, the heat receiving section casing extends in a third direction and the cross-sectional area perpendicular to the third direction is formed as a third cross-sectional area, and at least one of the first cross-sectional area and the second cross-sectional area is formed to be larger than the third cross-sectional area.

12. The apparatus comprises: a heat receiving section that receives heat from the outside to evaporate a liquid-phase working fluid; a heat dissipation section that condenses a gaseous-phase working fluid that flows in from the heat receiving section and releases heat to the outside; and a circulation section that circulates the working fluid between the heat receiving section and the heat dissipation section, wherein the heat receiving section comprises an evaporator that evaporates the liquid-phase working fluid and a heat receiving section casing that houses the evaporator; the heat dissipation section comprises a condensing section that condenses the gaseous-phase working fluid and a heat dissipation section casing that houses the condensing section; the circulation section comprises: a steam pipe that allows the gaseous-phase working fluid discharged from the evaporator to flow out to the condensing section; a reservoir that stores the liquid-phase working fluid that flows in from the condensing section in an internal space and allows the working fluid in the internal space to flow out to the evaporator; and a circulation section casing that houses the steam pipe and the reservoir spaced apart from each other in a single containment space and is connected to the heat receiving section casing and the heat dissipation section casing. The condensing section is a heat exchanger having a spiral channel extending spirally along the outer wall of the heat dissipation section casing, and an outlet channel formed downstream of the spiral channel in the direction of the working fluid flow, extending toward the circulation section casing at a position spaced apart from the spiral channel on the radially inner side of the spiral channel, and through which the working fluid flows toward the reservoir.

13. A reactor comprising a core and a heat exchanger that releases heat received from the core to an external heat utilization device, wherein the heat exchanger comprises a heat receiving section that receives heat from the core and evaporates a liquid-phase working fluid, a heat dissipation section that condenses a gaseous-phase working fluid flowing in from the heat receiving section and releases heat to the heat exchanger, and a circulation section that circulates the working fluid between the heat receiving section and the heat dissipation section, wherein the heat receiving section comprises an evaporator that evaporates the liquid-phase working fluid and a heat receiving section casing that houses the evaporator, the heat dissipation section comprises a condensing section that condenses the gaseous-phase working fluid and a heat dissipation section casing that houses the condensing section, and the circulation section comprises a steam pipe that allows the gaseous-phase working fluid discharged from the evaporator to flow out to the condensing section, and a reservoir that stores the liquid-phase working fluid flowing in from the condensing section in an internal space and allows the working fluid in the internal space to flow out to the evaporator, A nuclear reactor having a circulation casing that houses the steam pipe and the reservoir, and is connected to the heat receiving casing and the heat dissipation casing.

14. The reactor according to claim 13, wherein the tip of the heat receiving section casing is a heat receiving surface that receives heat from the reactor core.

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