Piping structure of a fast reactor

Abstract

The present invention provides a fast reactor piping structure that can reduce damage in the event of a sodium leak, regardless of the amount of sodium leaked. [Solution] The piping structure 2 of this fast reactor comprises a pipe body 20 through which liquid sodium flows, an enclosure 40 that covers the pipe body 20 from the outer circumference, and a partition structure 70 disposed inside the enclosure 40. The enclosure 40 has a lid member 41 that covers the pipe body 20 from above, and a trough member 42 that covers the pipe body 20 from below and faces the lid member 41 from below. The partition structure 70 has an upper partition plate 71 fixed to the lid member 41, and a lower partition plate 72 fixed to the trough member 42 with a gap X between it and the upper partition plate 71.

Description

Technical Field

[0001] The present invention relates to a piping structure of a fast reactor.

Background Art

[0002] In a fast reactor or a fast breeder reactor, liquid sodium (hereinafter sometimes simply referred to as sodium) is used as a coolant. This sodium flows between various external devices through pipes communicating with the reactor core. As a specific example of this type of pipe, for example, the one described in Patent Document 1 below is known. In the device according to Patent Document 1 below, a cylindrical blocking body that covers the pipe body from the outside is provided. When sodium leaks from the pipe body, it is said that further scattering and diffusion of sodium to the outside can be suppressed by being blocked by the blocking body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the configuration according to Patent Document 1 above, the space inside the enclosure (blocking body) is continuous in the longitudinal direction of the pipe. Therefore, for example, if sodium leakage occurs at one location, sodium will diffuse indefinitely throughout the space, and there is a risk that the reaction between sodium and the air in the space will gradually progress. Then, there is a problem that the products diffuse due to the combustion of sodium, or the damaged area expands, and the recovery work takes a long time. On the other hand, if the space is completely partitioned by a partition wall, there is also a concern that the leaked sodium will fill one partition and become a high-pressure state, and the subsequent damage will rather increase.

[0005] Therefore, the present invention has been made in view of these points, and aims to provide a piping structure for a fast reactor that can reduce damage in the event of a sodium leak, regardless of the amount of sodium leaked. [Means for solving the problem]

[0006] A piping structure for a fast reactor according to one embodiment of the present invention comprises a piping body through which liquid sodium flows, an enclosure covering the piping body from the outer periphery, and a partition structure disposed within the enclosure, wherein the enclosure has a lid member covering the piping body from above and a trough member covering the piping body from below and facing the lid member from below, and the partition structure has an upper partition plate fixed to the lid member and a lower partition plate fixed to the trough member with a gap between it and the upper partition plate.

[0007] The piping body is inserted through an opening formed in the upper partition plate and is provided to be displaceable relative to the upper partition plate, and may further have a connecting portion made of an elastic material that closes the space between the piping body and the opening.

[0008] When viewed from the direction in which the pipe body extends, the gap may be located below the boundary between the cover member and the gutter member.

[0009] A piping structure for a fast reactor in one embodiment of the present invention may further include a support member inserted through a through hole formed in at least one of the lid member and the trough member to support the piping body, and an elastic closing portion formed of an elastic material that closes the space between the edge of the through hole and the support member.

[0010] The gutter member is provided with a wiring outlet through which wiring for supplying power to auxiliary equipment arranged around the main body of the piping is inserted, and the gap may be located below the wiring outlet.

[0011] The inner bottom surface of the gutter member may extend downward as the pipe body extends from one side to the other in the direction in which it extends.

[0012] The above-described piping structure may further include a heat-insulating member that covers the piping body from the outer circumferential side, and partition spacers that divide the space between the outer circumferential surface of the piping body and the inner circumferential surface of the heat-insulating member into a plurality of sections in the direction in which the piping body extends. [Effects of the Invention]

[0013] The present invention provides a piping structure for fast reactors that can reduce damage in the event of a sodium leak, regardless of the amount of sodium leaked. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram showing the configuration of a fast reactor according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view showing the configuration of a piping structure according to an embodiment of the present invention. [Figure 3] This is a cross-sectional view along line AA in Figure 2. [Figure 4] This is a cross-sectional view along line BB in Figure 2. [Figure 5] This is a cross-sectional view along the CC line in Figure 2. [Figure 6] This is a cross-sectional view showing a first modified example of a piping structure according to an embodiment of the present invention. [Figure 7] This is a cross-sectional view showing a second modified example of a piping structure according to an embodiment of the present invention. [Figure 8] This is a cross-sectional view showing a third modified example of a piping structure according to an embodiment of the present invention. [Modes for carrying out the invention]

[0015] (overview) The pipe structure according to an embodiment of the present invention will be described later with reference to the drawings, and the outline is as follows. That is, the main feature of the present invention is that a partition structure is provided inside an enclosure that covers a pipe body. As a result, air cannot freely flow in and out, so in a unit area where sodium leakage has occurred, sodium reacts with air and burns, and the temperature and internal pressure in the space rise. Thus, fresh air cannot easily enter from the adjacent partition space through the gap, and the effect of suppressing combustion can be obtained.

[0016] The fast reactor 1 and the pipe structure 2 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. The fast reactor 1 according to this embodiment is a tank-type fast reactor. This fast reactor 1 extracts energy while controlling a nuclear fission chain reaction using, for example, uranium, plutonium, or the like as fuel.

[0017] (Configuration of the fast reactor 1) As shown in FIG. 1, the fast reactor 1 includes a reactor vessel 10, a reactor core 11, an intermediate heat exchanger 12, a coolant circulation pump 13, in-vessel piping 14, a steam generator 15, and a pipe structure 2.

[0018] The reactor vessel 10 is, for example, a vessel with a diameter of about 15 m to 20 m. The reactor core 11 is housed inside the reactor vessel 10. The reactor core 11 is provided with a core fuel containing a fissionable material and control rods for controlling the core reactivity. Although not shown in the figure, the control rods are driven by a control rod drive mechanism to move forward and backward in the vertical direction. The control rod drive mechanism controls the insertion amount of the control rods between the core fuels. Thereby, the nuclear fission of the core fuel is controlled, and the heat output in the reactor core 11 is controlled. The reactor core 11 heats up sodium, which is a liquid metal as a primary coolant. In the following description, liquid sodium may simply be referred to as "sodium". Also, sodium before heating may be referred to as low-temperature sodium, and sodium that has been heated to a high-temperature state may be referred to as high-temperature sodium.

[0019] In the reactor vessel 10, a free liquid surface is set, and cover gas such as argon gas is enclosed above the liquid surface. Thereby, the reactor vessel 10 absorbs the increase and decrease in volume due to the temperature change of sodium as a coolant in the gas space above the liquid surface.

[0020] The intermediate heat exchanger 12 has an inflow window for allowing high-temperature sodium to flow in and an outflow window for allowing low-temperature sodium after heat exchange to flow out. The intermediate heat exchanger 12 performs heat exchange between the high-temperature sodium flowing in from the inflow window and sodium functioning as a secondary coolant. Specifically, due to the action of the coolant circulation pump 13, high-temperature sodium whose temperature has risen to, for example, 550°C in the core 11 flows into the inlet of the intermediate heat exchanger 12. The flowing high-temperature sodium exchanges heat with the secondary sodium functioning as a secondary coolant, and becomes low-temperature sodium whose temperature has dropped to, for example, 400°C. The low-temperature sodium flows out from the outflow window to the lower part of the reactor vessel 10. The secondary sodium flows into the steam generator 15 through the pipe body 20 of the pipe structure 2 described later. In the steam generator 15, the secondary sodium heats water to generate steam for driving a turbine (not shown).

[0021] The coolant circulation pump 13 pumps the low-temperature sodium flowing out from the intermediate heat exchanger 12 into the in-vessel piping 14. The in-vessel piping 14 guides the low-temperature sodium pumped by the coolant circulation pump 13 to the core 11.

[0022] (Configuration of the pipe structure 2) Next, referring to FIGS. 2 to 5, the configuration of the pipe structure 2 will be described. As shown in FIG. 2, the pipe structure 2 includes a pipe body 20, a heat insulating material 30, an enclosure 40, a pipe support structure 50, a gutter support leg 60, a partition structure 70, a compensator 80, and a transfer pipe 90.

[0023] (Pipe body 20) The main piping body 20 forms a loop-shaped pipeline that includes the steam generator 15 described above. Liquid sodium, used as a secondary coolant, flows through the inside of the main piping body 20. The cross-sectional shape of the main piping body 20 is, for example, circular. The direction in which the main piping body 20 extends is determined as appropriate according to the plant design and specifications. As an example, as shown in Figure 2, in this embodiment, the main piping body 20 has a horizontal section 21 extending horizontally, a vertical section 22 extending vertically perpendicular to the horizontal section 21, and an elbow section 23 connecting the horizontal section 21 and the vertical section 22. The following will mainly describe the configuration around the horizontal section 21.

[0024] (Insulating material 30) The insulation material 30 is provided to keep the sodium flowing inside the pipe body 20 warm and ensure its fluidity. The insulation material 30 comprises an inner panel 31, an insulation material body 32, an outer panel 33, and a partition spacer 34. The inner panel 31 is cylindrical and covers the pipe body 20 from the outer periphery with a gap. This gap can accommodate the auxiliary equipment 80, which will be described later. The insulation material body 32 is attached to the outer circumferential surface of the inner panel 31. The insulation material body 32 is made of a material with relatively low thermal conductivity, such as rock wool or Fineflex (registered trademark). The outer circumferential surface of the insulation material body 32 is covered by the outer panel 33. The outer panel 33 and the inner panel 31 are made of metal and serve to maintain the shape of the insulation material body 32. The partition spacer 34 divides the space between the inner panel 31 and the outer circumferential surface of the pipe body 20 into multiple sections in the direction in which the pipe body 20 extends. The presence of these partition spacers 34 has the effect of restricting the diffusion of sodium aerosols. The partition spacer 34 may be composed of a single component or may be composed of a combination of multiple components.

[0025] (Enclosure 40) The enclosure 40 is cylindrical and covers the pipe body 20 from the outer circumference. The enclosure 40 has a lid member 41 and a gutter member 42. In the horizontal section 21, the lid member 41 covers the upper half of the pipe body 20 from above. As an example, the lid member 41 is semi-cylindrical with the direction in which the pipe body 20 extends as its central axis.

[0026] In the section corresponding to the horizontal portion 21 of the pipe body 20, the gutter member 42 covers the lower half of the pipe body 20 from below. As shown in Figure 3, the gutter member 42 has a trapezoidal cross-section when viewed from the direction in which the pipe body 20 extends. Specifically, the lower portions of the pair of inner surfaces 43 that face each other horizontally on the inner surface of the gutter member 42 extend in a direction that separates them from each other as you move from bottom to top. Furthermore, when viewed from the direction in which the pipe body 20 extends, the inner bottom surface 44 of the gutter member 42 is parallel to the horizontal direction. Note that "horizontal" here refers to an substantially horizontal state, and a small error is permissible.

[0027] The cover member 41 and the gutter member 42 are assembled with their inner surfaces facing each other from above and below. For example, the cover member 41 and the gutter member 42 are joined to each other by bolts 100.

[0028] Furthermore, the inner bottom surface 44 of the gutter member 42 extends downward as it moves from one side to the other in the direction in which the pipe body 20 extends. In other words, the inner bottom surface 44 is inclined with respect to the direction in which the pipe body 20 extends. Note that the entire gutter member 42 may be inclined as described above, or only the inner bottom surface 44 may be inclined. Also, the lid member 41 may be inclined in a similar manner to the inclination of the gutter member 42. In any case, it is desirable that the inclination angle of each member with respect to the horizontal direction is, for example, about 1° to 5°. Also, because the inclination angle is so small, the illustration of this inclination angle is omitted in Figure 2.

[0029] A transfer pipe 90 for discharging leaked sodium to the outside is provided in the lowest region of the gutter member 42. Although not shown in detail, the transfer pipe 90 is connected to an external tank.

[0030] A space is formed between the inner surface of the enclosure 40 and the outer surface of the pipe body 20. This space is a capture space V that captures leaked sodium to prevent the leakage of the leaked sodium from the pipe body 20 to the outside. The trough member 42 functions as a transport path to guide the leaked sodium to the transport pipe 90.

[0031] Furthermore, the enclosure 40 corresponding to the vertical section 22 has the same configuration as the enclosure 40 of the horizontal section 21, except that the direction of extension of the piping body 20 is different.

[0032] (Piping support structure 50) The pipe support structure 50 connects the pipe body 20 to a stationary member (not shown) such as a fixed wall of the building. As shown in Figure 2 or Figure 3, the pipe support structure 50 has a support member 51 and an elastic closing part 52. The support member 51 is columnar in shape and extends radially from the outer circumferential surface of the pipe body 20. In sections where the pipe body 20 is laid horizontally, this support member 51 is attached to the upper half of the pipe body 20. In this embodiment, the support member 51 extends upward from the top of the cross-section of the pipe body 20.

[0033] The lid member 41 of the enclosure 40 described above has a through hole 53 through which the support member 51 is inserted. The through hole 53 is, for example, circular or elliptical. An annular space is formed between the edge of the through hole 53 and the outer surface of the support member 51. This space is formed to a size such that the support member 51 and the lid member 41 do not interfere with each other when, for example, an earthquake occurs and the pipe support structure 50, pipe body 20, and enclosure 40 vibrate. This space is also formed to a size such that the support member 51 and the lid member 41 do not interfere with each other when deformation occurs due to thermal expansion of the pipe body 20. In this embodiment, an example in which the through hole 53 is formed in the lid member 41 is described, but the through hole may be formed in the gutter member 42, or in both the lid member 41 and the gutter member 42.

[0034] The above space is closed by an elastic closing portion 52. The elastic closing portion 52 is an annular shape that extends from the edge of the through hole 53 to the outer surface of the support member 51. For example, the elastic closing portion 52 is bellows-shaped with concentric grooves and depressions around the support member 51. The elastic closing portion 52 is made of, for example, an elastic material. The elastic closing portion 52 is made of a material with relatively high heat resistance. Note that the elastic closing portion 52 is not limited to a bellows shape, and may have any shape as long as it is expandable and / or deformable.

[0035] Multiple such pipe support structures 50 are provided at intervals along the extending length of the pipe body 20. The support members 51 may also be provided penetrating the gutter member 42.

[0036] (Gutter support legs 60) The gutter support legs 60 support the gutter member 42 of the enclosure 40 from below. In other words, the gutter support legs 60 bear the weight of the enclosure 40. The gutter support legs 60 connect the outer surface of the gutter member 42 to the floor surface of the building in the vertical direction. As an example, as shown in Figure 4, a pair of gutter support legs 60 are provided at intervals in the circumferential direction of the pipe body 20 when viewed from the direction in which the pipe body 20 extends. Also, as shown in Figure 2, multiple gutter support legs 60 are provided at intervals along the extending length of the pipe body 20.

[0037] (Partition structure 70) As shown in Figure 2, the partition structure 70 divides the capture space V within the enclosure 40 into multiple unit regions V1. That is, multiple partition structures 70 are provided within the enclosure 40 at intervals in the direction in which the piping body 20 extends. As shown in Figure 4, the partition structure 70 has an upper partition plate 71 and a lower partition plate 72. At least a portion of the upper partition plate 71 is fixed to the lid member 41. A portion of the upper partition plate 71, including the lower half, may be fixed to the gutter member 42. The upper partition plate 71 is plate-shaped and extends along a plane perpendicular to the direction in which the piping body 20 extends. The outer edge of the upper partition plate 71 is fixed to the inner surface of the lid member 41, for example, by welding. The upper partition plate 71 may be detachably attached to the lid member 41. For example, the upper partition plate 71 may be attached to the lid member 41 by fasteners such as bolts.

[0038] The upper partition plate 71 has a circular opening 73 through which the pipe body 20 is inserted. A space is formed between the edge of this opening 73 and the outer surface of the pipe body 20. This space is sized so that the insulation material 30 on the outside of the pipe body 20 and the upper partition plate 71 do not interfere with each other when the pipe body 20 and the partition structure 70 vibrate during an earthquake, or when the pipe body 20 undergoes thermal expansion. With this configuration, the pipe body 20 is provided so that it can be displaced relative to the upper partition plate 71.

[0039] The above-mentioned space is closed by the connecting portion 74. For example, the connecting portion 74 is a ring-shaped bellows made of an elastic material with relatively high heat resistance, similar to the elastic closing portion 52 described above. However, the connecting portion 74 is not limited to a bellows shape and may have any shape as long as it is expandable and / or deformable.

[0040] The lower partition plate 72 is fixed to the gutter member 42. The outer edge of the lower partition plate 72 is fixed to the inner surface of the gutter member 42, for example, by welding. The lower partition plate 72, like the upper partition plate 71, is plate-shaped and extends along a plane perpendicular to the direction in which the pipe body 20 extends. The positions of the upper partition plate 71 and the lower partition plate 72 in the direction in which the pipe body 20 extends are the same. The lower partition plate 72 may be detachably attached to the gutter member 42, similar to the above description regarding the fixing of the upper partition plate 71, or it may be attached to the cover member 41 by fasteners such as bolts.

[0041] A gap X is formed between the lower edge of the upper partition plate 71 and the upper edge of the lower partition plate 72. The edges of the upper partition plate 71 and the lower partition plate 72 are, for example, parallel to each other. The gap X is a linear shape that extends horizontally from one inner surface 43 to the other inner surface 43 when viewed from the direction in which the pipe body 20 extends. The dimensions of the gap X in the vertical direction are, for example, constant over the entire length of the gap X. Note that "parallel" refers to substantially parallel, and a small error is permissible. The dimensions of the gap X (here, the vertical dimensions in the figure) are determined appropriately considering the fluidity of sodium, and are, for example, in the range of a few millimeters to a few tens of millimeters. Because such a gap X is formed, adjacent unit regions V1 partitioned by the partition structure 70 are not completely separated, and the unit regions V1 are in communication with each other through the gap X.

[0042] As will be described later, the partition structure 70 has the advantage of limiting the diffusion range of sodium in the event of a sodium leak. However, in the case of a structure in which the space inside the enclosure 40 is completely partitioned by a single plate-like member, for example, the leaked sodium may fill the compartment and create a high-pressure state, potentially increasing the subsequent damage. Therefore, in this embodiment, a partition structure 70 is adopted that is composed of multiple members and has gaps X through which sodium and atmospheric gas can pass. With such a configuration, the situation in which the internal pressure of the leaked compartment becomes excessively high is avoided, and the spread of damage due to sodium leakage is suppressed.

[0043] The height dimension from the inner bottom surface 44 of the gutter member 42 to the bottom of the gap X is appropriately determined based on the assumed maximum liquid level height of leaked sodium. Regarding the positional relationship between the boundary between the lid member 41 of the enclosure 40 and the gutter member 42 (the part where the lid member 41 and the gutter member 42 are connected by bolts 100) and the gap X, in this embodiment, as shown in Figure 4, the gap X is located below the boundary when viewed from the direction in which the pipe body 20 extends. For example, it is desirable that the gap X is located within a range of 50% or less from the inner bottom surface 44 of the gutter member 42 to the boundary.

[0044] In this embodiment, with the configuration described above, the leaked sodium flows through the gap X into other unit regions V1 before the liquid level of the leaked sodium reaches the boundary between the lid member 41 and the trough member 42. This prevents the sodium from leaking to the outside through the boundary.

[0045] Furthermore, it is desirable that the partition structure 70 be provided only in the horizontal section 21 as described above. This is because in the vertical section 22, sodium naturally flows downward due to gravity, so there is no need to partition it with the partition structure 70.

[0046] (auxiliary device 80) As shown in Figure 5, auxiliary equipment 80 is installed around the main piping body 20. As an example, the auxiliary equipment 80 includes a heater 81 and instrumentation equipment 82. The heater 81 is provided to preheat the sodium inside the main piping body 20. The heater 81 includes a heater body 83 and wiring 85a. The heater body 83 is attached to the outer surface of the main piping body 20. The heater body 83 is, for example, an electric heating element. The instrumentation equipment 82 includes an instrumentation equipment body 84 such as a thermometer and wiring 85b. Power is supplied to the heater body 83 and the instrumentation equipment body 84, and various signals are transmitted and received through wiring 85a and wiring 85b, respectively. The gutter member 42 of the enclosure 40 has a wiring exit section 45 formed therein, which is an opening for inserting the wiring 85a and wiring 85b. These wiring outlets 45 are located above the gap X of the partition structure 70 described above (i.e., the gap X is located below the wiring outlets 45).

[0047] (Effects and Benefits) In conventional configurations, for example, the space inside the enclosure 40 is typically continuous along the longitudinal direction of the piping. Therefore, if sodium leaks in one place, for example, the sodium will diffuse throughout the entire space, and there is a risk that the reaction between the sodium and the air in the space will gradually progress. This can lead to the diffusion of products due to the combustion of sodium, or the expansion of the damaged area, resulting in the problem of requiring a long time for recovery work. On the other hand, if the space is completely partitioned by a partition wall, there is a concern that the leaked sodium will fill one compartment, creating a high-pressure state, which could actually increase the subsequent damage. To solve this problem, the above-described configurations are adopted in this embodiment.

[0048] According to the above configuration, a partition structure 70 is provided inside the enclosure 40. This partition structure 70 has an upper partition plate 71 and a lower partition plate 72. Furthermore, a gap X is formed between the upper partition plate 71 and the lower partition plate 72. As a result, when sodium leaks from the main body of the piping 20, if the amount of leakage is relatively small, the leaked sodium will remain in the unit area V1 partitioned by the lower partition plate 72. In other words, the leaked sodium will not diffuse into other unit areas V1. Therefore, the area in which products diffuse or are damaged by the combustion of sodium can be kept small.

[0049] On the other hand, if the amount of sodium leakage is relatively large, the sodium liquid level will overflow the gap X between the lower partition plate 72 and the upper partition plate 71 and flow into other adjacent unit regions V1. Therefore, it is possible to reduce the possibility of sodium becoming trapped in one unit region V1. This prevents the internal pressure of the leaked compartment from becoming excessively high, and suppresses the spread of damage caused by the sodium leak. Thus, with the above configuration, it is possible to suppress the spread of damage caused by sodium leakage, regardless of the amount of sodium leakage.

[0050] According to the above configuration, the pipe body 20 is provided so as to be displaceable relative to the upper partition plate 71. Furthermore, a connecting portion 74 made of an elastic material is provided in the opening 73 through which the pipe body 20 is inserted. Therefore, even if an external force such as seismic motion is applied to the pipe body 20, or if thermal expansion occurs in the pipe body 20 due to the heat of sodium, interference between the pipe body 20 and the upper partition plate 71 and damage to the components are prevented, and the diffusion of sodium can be suppressed by the connecting portion 74 provided in the opening 73. Furthermore, the elastic deformation of the connecting portion 74 makes it possible to absorb or dampen vibrations caused by earthquakes, etc. This reduces the possibility of vibrations being directly applied to the pipe body 20, and further improves the seismic resistance of the pipe body 20.

[0051] According to the above configuration, the gap X between the upper partition plate 71 and the lower partition plate 72 is located below the boundary between the lid member 41 and the gutter member 42. Therefore, as mentioned above, leakage of sodium to the outside through the boundary can be avoided.

[0052] According to the above configuration, the pipe body 20 is supported by a support member 51. Furthermore, the space between the edge of the through-hole 53 of the lid member 41 or gutter member 42 through which the support member 51 is inserted and the support member 51 is closed by an elastic closing portion 52 made of an elastic material. As a result, even if an external force such as an earthquake is applied to the pipe body 20, or if thermal expansion occurs in the pipe body 20, interference between the support member 51 and the lid member 41 (or gutter member 42) and damage to the members is prevented, and the diffusion of sodium can be suppressed by the elastic closing portion 52 provided in the through-hole 53.

[0053] In particular, since the inside and outside of the enclosure 40 are separated by the elastic sealing section 52, the possibility of outside air flowing into the enclosure 40 is reduced. This significantly reduces the risk of a sodium fire caused by the reaction of outside air with leaked sodium. Furthermore, the elastic sealing section 52 can absorb or dampen vibrations caused by earthquakes, etc., through elastic deformation. This reduces the possibility of vibrations being directly applied to the pipe body 20, further improving the seismic resistance of the pipe body 20.

[0054] According to the above configuration, the wiring 85a and 85b of the auxiliary equipment 80, including the heater 81 and instrumentation equipment 82, are inserted through the wiring outlet 45 provided on the gutter member 42. Furthermore, the gap X between the upper partition plate 71 and the lower partition plate 72 is located below the wiring outlet 45. As a result, the liquid level of leaked sodium flows through the gap X to other adjacent unit areas V1 before reaching the opening that serves as the wiring outlet 45. Therefore, leakage of sodium to the outside through the wiring outlet 45 can be avoided. In addition, since the wiring outlet 45 is not formed on the lid member 41, there is no need to consider the routing of the wiring 85a and 85b when detaching the lid member 41 from the gutter member 42. This also makes it possible to carry out maintenance work on the piping structure 2 more smoothly.

[0055] According to the above configuration, the inner bottom surface 44 of the trough member 42 is inclined with respect to the horizontal direction. As a result, when sodium leakage occurs, the leaked sodium flows downward along the inclination of the trough member 42. In particular, when the sodium liquid level exceeds the height of the gap X, the sodium can be smoothly guided downward through this gap X. Therefore, the leaked sodium can be efficiently recovered by the transfer pipe 90 and tank provided at the lower end. As a result, post-incident treatment in the event of a sodium leak can be carried out even more smoothly.

[0056] Furthermore, a secondary effect of tilting the gutter member 42 is that it is sufficient to install the transfer pipe 90 only at the bottom of the gutter member 42. This reduces the need to install transfer pipes 90 in multiple locations, saving space within the building and increasing the flexibility of the layout of the piping structure 2.

[0057] In the above configuration, the lid member 41 is fixed to the gutter member 42. This reduces the possibility of the lid member 41 detaching from the gutter member 42 when an unexpected external force is applied to the enclosure 40, such as during an earthquake. Therefore, it is possible to ensure the integrity of the piping structure 2. Furthermore, in the above embodiment, since the lid member 41 and the gutter member 42 are connected by bolts 100, the lid member 41 can be easily removed during maintenance. Therefore, it is possible to ensure integrity without impairing the workability during maintenance.

[0058] Embodiments of the present invention have been described above. It is possible to make various changes and modifications to each of the above-described configurations without departing from the spirit of the present invention.

[0059] <Variation> For example, the cross-sectional shape of the gutter member 42 is not limited by the above embodiment. As a first modification, as shown in Figure 6, the gutter member 42 may have a rectangular shape. Furthermore, as a second modification, as shown in Figure 7, the gutter member 42 may be semi-cylindrical with respect to the central axis of the pipe body 20. Also, as a third modification, as shown in Figure 8, the gutter member 42 may be trapezoidal, similar to the lid member 41. In any of these configurations, the same effects as described above can be obtained by providing a partition structure with a gap. However, when the gutter member 42 has the shape shown in Figures 3 to 5, and the shape shown in Figure 6, a larger volume below the gap X can be formed compared to the semi-cylindrical configuration. Therefore, it is advantageous in that the amount of sodium that can be contained in one compartment can be increased without increasing the size of the enclosure 40.

[0060] In addition, the auxiliary equipment 80 is not limited to the heater 81 and instrumentation equipment 82 described above, and various devices can be used as auxiliary equipment 80 as needed. Specifically, examples include pressure gauges and liquid level sensors.

[0061] Furthermore, although the above embodiment described an example in which the piping structure 2 is used for transferring secondary coolant, the application of the piping structure 2 is not limited to this. As another example, it can also be applied to the piping of the primary cooling system. Moreover, the piping structure 2 can be applied not only to the tank-type fast reactor 1 described above, but also to loop-type fast reactors. In either case, the same effects and advantages as described above can be obtained.

[0062] Furthermore, to improve the fluidity of sodium, the inner bottom surface 44 of the trough member 42 described in the above embodiment can be polished or other low-friction coatings can be applied. In this case, the sodium flows immediately along the inner bottom surface 44, allowing sodium recovery to be completed in an even shorter time. Therefore, post-incident treatment in the event of a sodium leak can be carried out even more quickly and smoothly.

[0063] In addition, the direction of extension of the piping body 20 is not limited by the embodiments described above. Specifically, in addition to the horizontal section 21, vertical section 22, and elbow section 23 exemplified in the embodiments above, there may be locally provided sections that extend obliquely to the vertical or horizontal direction.

[0064] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of its gist. For example, all or part of the apparatus can be configured by functionally or physically distributing and integrating in any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combinations are combined with the effects of the original embodiments. [Explanation of Symbols]

[0065] 1...Fast reactor 2… Piping structure 10…Reactor vessel 11… core 12…Intermediate heat exchanger 13…Coolant circulation pump 14…Furnace piping 15…Steam generator 20... Piping body 21…Horizontal part 22…Vertical section 23... Elbow section 30…Heat insulation material 31…Interior panels 32…Insulation material body 33…Exterior plate 34… Partition spacer 40…Enclosure 41...Lid component 42...Gutter parts 43…Inner surface 44…Inner bottom surface 45...Wiring drawer 50…Piping support structure 51…Support member 52...Elastic occlusion 53…Through hole 60... Gutter support legs 70... Partition structure 71... Upper partition plate 72...Lower partition plate 73…Opening 74...Connection part 80…Auxiliary equipment 81... Heater 82…Instrumentation equipment 83... Heater unit 84…Instrumentation equipment main unit 85a, 85b… wiring 90…Transfer pipe 100... Volts V…Capturing space V1...Unit domain X... Gap

Claims

1. The main body of the piping through which liquid sodium flows, An enclosure that covers the main body of the piping from the outer periphery, A partition structure arranged within the enclosure, A piping structure equipped with, The aforementioned enclosure is A cover member that covers the pipe body from above, The pipe body is covered from below, and the gutter member is opposed to the cover member from below, It has, The aforementioned partition structure is, An upper partition plate fixed to the lid member, A lower partition plate is fixed to the gutter member with a gap between it and the upper partition plate, A piping structure for a fast reactor having the following features.

2. The piping body is inserted through an opening formed in the upper partition plate and is provided to be displaceable relative to the upper partition plate. The fast reactor piping structure according to claim 1, further comprising a connecting portion made of an elastic material that closes the space between the piping body and the opening.

3. The piping structure for a fast reactor according to claim 1 or 2, wherein, when viewed from the direction in which the piping body extends, the gap is located below the boundary between the lid member and the trough member.

4. A support member is inserted through a through hole formed in at least one of the lid member and the gutter member, and supports the main body of the piping, The elastic closing portion, formed of an elastic material, closes the space between the edge of the through hole and the support member. The piping structure for a fast reactor according to claim 1 or 2, further comprising the above.

5. The gutter member is provided with a wiring outlet through which wiring for supplying power to auxiliary equipment arranged around the main body of the piping is inserted. The piping structure for a fast reactor according to claim 1 or 2, wherein the gap is located below the wiring outlet.

6. The piping structure for a fast reactor according to claim 1 or 2, wherein the inner bottom surface of the trough member extends downward as the pipe body extends from one side to the other side in the direction in which the pipe body extends.

7. A heat-insulating member that covers the main body of the piping from the outer circumference, The space between the outer circumferential surface of the pipe body and the inner circumferential surface of the heat-insulating member is divided into multiple sections by partition spacers in the direction in which the pipe body extends, The piping structure for a fast reactor according to claim 1 or 2, further comprising the above.

Images