Seawater sampling system

Abstract

To provide a seawater sampling system which can improve the maintenance property.SOLUTION: A seawater sampling system for monitoring the concentration of radiation in a sea area around a nuclear power plant includes a water intake facility provided at the top edge of a breakwater extending from a land to sea. The water intake facility includes: a water intake pump provided in a breakwater; a water intake tube connected to the water intake pump and extending to below the water level of sea; and a nozzle connected to the lower end of the water intake pipe. The nozzle includes: a lower cylindrical part in the shape of a cylinder uniformly extending vertically, the lower end of the lower cylindrical part serving as a water intake port of seawater; an upper cylindrical part connected to the upper end of the lower cylindrical part, the diameter of the upper cylindrical part reducing as extending upward so that the upper cylindrical part is connected to the lower end of the water intake pipe; and a division plate provided in the lower cylindrical part, the division plate being in the shape of a vertically extending plate and dividing the region in the lower cylindrical part into a plurality of regions when viewed in a vertical direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a seawater sampling system. [Background technology]

[0002] Nuclear power plants are located next to the sea, and treated water discharged from the nuclear power plants is discharged into the ocean. In order to assess the impact of such treated water on the ocean, the radioactivity concentration of seawater sampled from the ocean is measured. For example, Patent Document 1 discloses an example of a seawater sampling system. In this seawater sampling system, a water intake pipe is pulled out from a drum on land and laid along the seabed to offshore, and seawater samples are obtained from the seabed far from land. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility model registration No. 3198945 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when collecting seawater as a sample, foreign objects in the ocean may be sucked in along with the seawater. If the foreign objects are hard and dense objects such as stones, metals, or shells, the pump may malfunction. In addition, marine organisms may adhere to the inner surface of the intake pipe, eroding the cross-sectional area of ​​the intake pipe and reducing the suction performance. This increases the frequency of maintenance required for the pumps and water intake pipes.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a seawater sampling system that can improve maintainability. [Means for solving the problem]

[0006] In order to solve the above problems, the seawater sampling system disclosed herein is a seawater sampling system for monitoring radiation concentrations in the sea area around a nuclear power plant, and includes a water intake facility provided at the tip of a breakwater extending from land toward the ocean, the water intake facility including a water intake pump provided at the breakwater, a water intake pipe connected to the water intake pump and extending below the water surface of the ocean, and a nozzle connected to the lower end of the water intake pipe, the nozzle including a lower cylindrical portion having a cylindrical shape extending uniformly in the vertical direction and a lower end which serves as an intake port for the seawater, an upper cylindrical portion connected to the upper end of the lower cylindrical portion and which reduces in diameter as it extends upward and is connected to the lower end of the water intake pipe, and a dividing plate provided within the lower cylindrical portion and extending in the vertical direction, dividing the area within the lower cylindrical portion into multiple portions when viewed from the vertical direction. Effect of the Invention

[0007] According to the seawater sampling system of the present disclosure, maintainability can be improved. [Brief description of the drawings]

[0008] [Figure 1] 1 is a plan view showing an installation mode of a seawater sampling system according to a first embodiment. FIG. [Diagram 2] 1 is a schematic side view showing a general configuration of a seawater sampling system according to a first embodiment. FIG. [Diagram 3] 1 is a schematic side view of the main parts of the water intake equipment of the seawater sampling system according to the first embodiment. FIG. [Figure 4] 1 is an oblique view of the intake pipe and nozzle of the water intake equipment of the seawater sampling system according to the first embodiment. FIG. [Diagram 5] This is a vertical cross-sectional view including the axis of the water intake pipe and nozzle of the water intake equipment of the seawater sampling system related to the first embodiment. [Figure 6] 1 is a view from below of the water intake pipe and nozzle of the water intake equipment of the seawater sampling system according to the first embodiment. FIG. [Figure 7] 4A to 4C are diagrams illustrating the effects of the seawater sampling system according to the first embodiment. [Figure 8] A view from below of the water intake pipe and nozzle of the water intake equipment of the seawater sampling system related to the second embodiment. [Figure 9] A schematic side view of the main parts of the water intake equipment of the seawater sampling system according to the third embodiment. [Figure 10] A schematic plan view of the main parts of the water intake equipment of the seawater sampling system according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First Embodiment Next, a first embodiment of a seawater sampling system 10 according to the present disclosure will be described with reference to Figures 1 to 5. As shown in Figures 1 and 2, the seawater sampling system 10 is provided across land 1 and the tip of a breakwater 5.

[0010] A nuclear power plant is installed on land 1 shown in Fig. 1. Treated water from the nuclear power plant is discharged into the surrounding sea area. The seawater sampling system 10 of this embodiment takes seawater as a sample from the ocean 2 in the sea area surrounding the nuclear power plant and monitors the radiation concentration in the sample.

[0011] The breakwater 5 is a structure that extends from the land 1 toward the ocean 2. The breakwater 5 extends in a direction along the coastline as it approaches the ocean 2. As a result, a bay 3 is formed on one side of the breakwater 5 in the width direction, and the open ocean 4 spreads out on the other side of the breakwater 5 in the width direction. A wave-dissipating zone 6 made up of a large number of tetrapods is provided on the open ocean 4 side of the breakwater 5 in the direction in which the breakwater 5 extends.

[0012] <Seawater sampling system> As shown in FIG. 2, the seawater sampling system 10 includes a water intake facility 20, an on-shore facility 30, an installation member 40, and a cover member 50.

[0013] <Water intake equipment> The water intake facility 20 is a facility for taking in seawater as a sample from the ocean 2. The water intake facility 20 is provided at the tip of the breakwater 5. The water intake facility 20 has a water intake pump 24, a cyclone separator 25, a sterilization device 26, a settling tank 27, a water pump 28, and a power distribution unit and a signal transmission / reception unit 29.

[0014] <Water intake building> The water intake building 21 is provided on the tip of the breakwater 5, that is, at the tip of the top end 5a, which is the upper surface of the breakwater 5, facing the ocean 2. The water intake building 21 houses various devices of the water intake facility 20.

[0015] <Water intake pump> The water intake pump 24 is provided in the water intake building 21. The water intake pump 24 takes in seawater via a water intake section, which will be described later. The water intake pump 24 has an impeller therein, and is configured to be able to take in seawater and pump it out by rotating the impeller. The cyclone separator 25 is connected to the rear stage of the water intake pump 24 inside the water intake building 21. Seawater that has passed through the water intake pump 24 is guided to the cyclone separator 25. The cyclone separator 25 removes foreign matter in the seawater from the seawater.

[0016] <Sterilization device> The sterilization device 26 is connected to the downstream of the cyclone separator 25 inside the water intake building 21. The seawater from which foreign matter has been removed by the cyclone separator 25 is guided to the sterilization device 26. The sterilization device 26 sterilizes the seawater by irradiating it with sterilizing light such as ultraviolet light, for example, to prevent the proliferation of marine organisms in the downstream system. The settling tank 27 is connected to the rear stage of the sterilization device 26 inside the water intake building 21. The seawater sterilized by the sterilization device 26 is led to the settling tank 27. In the settling tank 27, relatively fine impurities that could not be removed by the cyclone separator 25 are precipitated, and the impurities are removed from the seawater.

[0017] <Water pump> The water supply pump 28 is connected to the rear stage of the settling tank 27 inside the water intake building 21. The water supply pump 28 sends out the seawater from which impurities have been removed in the settling tank 27 to the outside of the water intake building 21. In this way, in the water intake building 21, seawater flows through the water intake pump 24, the cyclone separator 25, the sterilization device 26, the settling tank 27 and the water supply pump 28 in that order.

[0018] <Power distribution section and signal transmission / reception section> The power distribution unit and signal transmission / reception unit 29 is provided in the water intake building 21. The power distribution unit and signal transmission / reception unit 29 distributes power supplied from the outside to various devices in the water intake building 21, and at the same time transmits signals to the various devices to control them. It also transmits signals to and receives signals from onshore facilities.

[0019] <Land-based facilities> The onshore facility 30 is a facility for analyzing and monitoring the seawater taken in by the water intake facility 20. The onshore facility 30 is provided on land 1. The onshore facility 30 has an onshore building 31, a buffer tank 32, a sampler pump 33, a filter 34, a radiation detection unit 35, a radiation monitor device 36, and a power supply unit and a signal transmission / reception unit 37.

[0020] <Onshore building> The onshore building 31 is provided on the land 1 near the end of the breakwater 5 on the land 1 side. The onshore building 31 houses various devices of the onshore facility 30. <Buffer tank> The buffer tank 32 is provided in the onshore building 31 and temporarily stores the seawater taken in by the water intake facility 20 . <Sampler pump> The sampler pump 33 is provided in the onshore building 31 at the rear of the buffer tank 32. The sampler pump 33 pumps seawater stored in the buffer tank 32 out of the buffer tank 32.

[0021] <filter> The filter 34 is provided in the onshore building 31 after the sampler pump 33. The filter 34 removes fine impurities that could not be removed by the cyclone separator 25 and the settling tank 27. Examples of fine impurities include minute marine organisms. The filter 34 removes impurities by filtration. Therefore, maintenance of the filter 34 requires work such as backwashing with seawater or water, or manual cleaning.

[0022] <Radiation detection section> The radiation detection unit is provided after the filter in the onshore building 31. The radiation detection unit detects the radiation concentration in the seawater that has passed through the filter . The radiation detection unit 35 may be, for example, a gamma ray measuring device, a beta ray measuring device, or even a tritium measuring device. These measuring devices may be provided in parallel with each other, and seawater may be introduced into each of them. Also, a plurality of filters 34 may be provided corresponding to each measuring device.

[0023] In this manner, within the onshore building 31, seawater flows through the buffer tank 32, the sampler pump 33, the filter 34, and the radiation detection unit 35 in that order. The seawater after the radiation concentration has been detected by the radiation detection unit 35 is discharged into the ocean 2, for example, via a pipe (not shown).

[0024] <Radiation monitor device> The radiation monitor device 36 is provided in the onshore building 31, and is electrically connected to the radiation detection unit 35. Data relating to the radiation concentration detected by the radiation detection unit 35 is transmitted to the radiation monitor device 36. The radiation monitor device 36 monitors and records the received data relating to the radiation concentration over time. The radiation monitor device 36 may be configured to issue an alarm when the radiation concentration exceeds a predetermined threshold value.

[0025] <Power supply unit and signal transmission / reception unit> The power supply unit and signal transmission / reception unit 37 is provided in the onshore building 31, and is connected to an external power system or an emergency power source. The power supply unit and signal transmission / reception unit 37 supplies power to various devices of the onshore facility 30, and also supplies power to the power distribution unit and signal transmission / reception unit 29 of the water intake facility 20 via a power supply and signal cable 42 (also referred to as a power cable 42) described later, to transmit and receive signals.

[0026] <Installation materials> 1 and 2, the installation member 40 connects the water intake facility 20 and the onshore facility 30. The installation member 40 extends along the breakwater 5 on the top end 5a of the breakwater 5. As shown in Fig. 2, the installation member 40 of this embodiment is a cord-like member including a water supply pipe 41 and a power supply and signal cable 42.

[0027] <Water pipe> The water supply pipe 41 is a pipe that sends seawater obtained by the water intake facility 20 to the onshore facility 30. The upstream end of the water supply pipe 41 in the seawater flow direction passes through the water intake building 21 of the water intake facility 20 and is connected to the water supply pump 28 in the water intake building 21. The downstream end of the water supply pipe 41 in the seawater flow direction passes through the onshore building 31 of the onshore facility 30 and is connected to the buffer tank 32 in the onshore building 31. As a result, seawater sent out by the water supply pump 28 is supplied to the buffer tank 32 via the water supply pipe 41.

[0028] <Power and signal cables> The power supply and signal cable 42 is a cable for supplying power and signals to the power distribution unit and signal transmission / reception unit 29 of the water intake facility 20. One end of the power supply and signal cable 42 is connected to the power supply unit and signal transmission / reception unit 37 in the onshore facility 30, and the other end of the power supply and signal cable 42 is connected to the power distribution unit and signal transmission / reception unit 29 of the water intake facility 20. In other words, the power supply and signal cable 42 electrically connects the power supply unit and signal transmission / reception unit 37 and the power distribution unit and signal transmission / reception unit 29. The power supply and signal cable 42 extends so as to be installed in parallel with the water supply pipe 41.

[0029] <Cover material> The cover member 50 is provided across the water intake facility 20 and the land facility 30 so as to cover the laying member 40 on the top end 5a of the breakwater 5. 3 and 4, the cover member 50 extends in the extension direction of the breakwater 5 along the edge of the top end 5a of the breakwater 5 on the bay 3 side. The cover member 50 is provided so as to protrude upward from the top end 5a. The installation member 40 is installed across the water intake facility 20 and the land facility 30 so as to pass through the inside of such a cover member 50.

[0030] <Water Intake Section Configuration> In addition to the above configuration, the water intake facility 20 of the seawater sampling system 10 has a water intake section for taking in seawater by a water intake pump 24. The water intake section has a water intake pipe 60, a nozzle 70, and a protective tube 90.

[0031] <Water intake pipe> As shown in FIG. 3, the water intake pipe 60 is a pipe for taking in seawater from the ocean 2, and extends in the vertical direction along the side surface 5b of the breakwater 5 at the tip of the breakwater 5. The lower part of the water intake pipe 60 is located below the seawater surface, and the lower end opens downward. The lower part of the water intake pipe 60 is cylindrical and extends in the vertical direction. As shown in Fig. 5, the inner circumferential surface of the lower part of the water intake pipe 60 is a small-diameter inner circumferential surface 60a with a uniform flow passage cross-sectional area in the vertical direction. The upper part of the water intake pipe 60 is exposed above the seawater surface. The upper end of the water intake pipe 60 is bent horizontally and connected to the water intake pump 24.

[0032] <Nozzle> The nozzle 70 is connected below the seawater surface to the lower end of the water intake pipe 60. As shown in detail in Figures 4 to 6, the nozzle 70 is cylindrical with its center on an axis O (the central axis O of the lower part of the water intake pipe 60) that extends in the vertical direction as a whole, and its lower end serves as a water intake port for taking in seawater. The nozzle 70 has a lower cylindrical portion 71 , an upper cylindrical portion 72 , and a dividing plate 80 .

[0033] <Lower cylinder part> The lower cylindrical portion 71 is a member that constitutes the lower portion of the nozzle 70, and has a tubular shape that extends in the vertical direction centered on the axis O. The lower cylindrical portion 71 has a cylindrical shape with an outer peripheral surface and an inner peripheral surface that have a uniform diameter in the vertical direction. As shown in FIG. 5, the inner peripheral surface of the lower cylindrical portion 71 is a large-diameter inner peripheral surface 71a. The flow path cross-sectional area defined by the large-diameter inner peripheral surface 71a (the flow path cross-sectional area along a horizontal plane perpendicular to the axis O) is uniform in the vertical direction. This flow path cross-sectional area is set larger than the flow path cross-sectional area of ​​the lower portion of the water intake pipe 60.

[0034] <Upper cylinder part> The upper cylindrical portion 72 is a member that constitutes the upper portion of the nozzle 70. The upper end of the lower cylindrical portion 71 is connected to the upper end of the lower cylindrical portion 71. The upper end of the upper cylindrical portion 72 is connected to the lower end of the water intake. The upper cylindrical portion 72 is centered on the axis O and has a tapered cylindrical shape in which the outer and inner peripheral surfaces decrease in diameter from bottom to top. As shown in Fig. 5, the inner peripheral surface of the upper cylindrical portion is a tapered inner peripheral surface 72a.

[0035] The outer diameter and inner diameter of the lower end of the upper cylindrical portion 72 are set to be equal to the outer diameter and inner diameter of the lower cylindrical portion 71. The outer diameter and inner diameter of the upper end of the upper cylindrical portion 72 are set to be equal to the outer diameter and inner diameter of the water intake pipe 60. That is, the large-diameter inner circumferential surface 71a of the lower cylindrical portion 71, the tapered inner circumferential surface 72a of the upper cylindrical portion 72, and the small-diameter inner circumferential surface 60a of the water intake pipe 60 are successively connected, so that the inner flow passage of the lower cylindrical portion 71, the inner flow passage of the upper cylindrical portion 72, and the inner flow passage of the water intake pipe 60 are continuously connected from below to above.

[0036] In this embodiment, the vertical dimension of the lower cylindrical portion 71 is set to be larger than the dimension of the upper cylindrical portion 72. The inner diameter of the lower cylindrical portion 71 is set to be, for example, 2 to 20 times, preferably 3 to 15 times, and more preferably 4 to 10 times, the inner diameter of the water intake pipe 60. The taper angle of the upper cylindrical portion 72 is appropriately set in accordance with these dimensions.

[0037] <Divided plate> The dividing plate 80 is provided inside the lower cylindrical portion 71. The dividing plate 80 divides the flow path inside the lower cylindrical portion 71 into multiple regions when viewed from the top-bottom direction. The dividing plate 80 is constructed by combining multiple plates extending in the vertical and horizontal directions. The dividing plate 80 is arranged radially around the axis O when viewed from the top-bottom direction. The dividing plate 80 divides the area inside the lower cylindrical portion 71 into multiple sector-shaped areas centered on the axis O when viewed from the top-bottom direction. In this embodiment, the area inside the lower cylindrical portion 71 is divided into four sector-shaped areas of the same shape centered on the axis O.

[0038] <Protective tube> As shown in Fig. 3, the protective tube 90 is a member for protecting the water intake pipe 60. The protective tube 90 has a cylindrical shape with a closed bottom and a closed lower end. Holes 90a penetrating from the inside to the outside are formed throughout the entire protective tube 90. In other words, the protective tube 90 is made of a porous structural material such as mesh or a porous plate. The protective tube 90 extends vertically so as to surround the lower part of the water intake pipe 60. The protective tube 90 is installed at a fixed distance from the side surface 5b of the breakwater 5 in the vertical direction.

[0039] A coating layer for preventing adhesion of marine organisms is formed on the inner and outer surfaces of the water intake pipe 60, the nozzle 70, and the protective tube 90. The coating layer is made of, for example, a fluorine-based resin such as polytetrafluoroethylene, a silicon-based resin, chrome plating, or the like.

[0040] <Action and effect> According to the seawater sampling system 10 configured as described above, seawater taken in by the water intake facility 20 at the tip of the breakwater 5 is sent to the onshore facility 30 via the water supply pipe 41. In the onshore facility 30, impurities are finally removed from the seawater by the filter 34, and then the radiation concentration is detected by the radiation detection unit 35. The detection results are then acquired by the radiation monitor device 36, allowing the radiation concentration of the seawater to be appropriately monitored.

[0041] In this embodiment, seawater is taken from the ocean 2 at the tip of a breakwater 5 that is separated from the land 1. This makes it possible to appropriately obtain seawater suitable for measuring radiation concentration without having to take in seawater from offshore, which is further away from the land 1.

[0042] In this embodiment, the water intake section prevents foreign matter from being mixed in when seawater is taken in.

[0043] That is, when the intake pump 24 is driven to start intake of seawater by the intake section, seawater is taken into the nozzle 70 from the intake port at the lower end of the nozzle 70, as shown in Fig. 7, and the seawater reaches the intake pump 24 via the intake pipe 60. By taking in water from this intake port, seawater flows in from the outside to the inside of the protective cylinder 90 through the hole 90a at a low speed. That is, a low-speed flow F0 with a relatively low flow speed is generated around the protective cylinder 90. At this time, seaweed such as wakame seaweed and cloth-like foreign objects such as plastic bags floating in the ocean 2 cannot pass through the hole 90a of the protective cylinder 90, and are captured by the outer circumferential surface of the protective cylinder 90.

[0044] Also, although the flow velocity of the seawater sucked in from the intake port at the lower end of the nozzle 70 is faster than the flow velocity of the seawater around the protective tube 90, the value is suppressed by the configuration of the nozzle 70. That is, the flow path cross-sectional area of ​​the lower cylinder part 71 in the nozzle 70 is sufficiently larger than the intake pipe 60. Furthermore, since the dividing plate 80 is provided inside the lower cylinder part 71, even if a vortex centered on the axis O is generated in the lower cylinder part 71, the vortex is canceled by colliding with the plate surface 80a of the dividing plate 80. That is, the dividing plate 80 functions as a baffle plate that cancels the vortex. As a result, the region divided by the dividing plate 80 inside the lower cylinder part 71 becomes a non-acceleration region R1 in which the increase in flow velocity is suppressed (see FIG. 5). Therefore, the flow velocity of the seawater sucked in from the lower end of the lower cylinder part 71 does not increase significantly, and the seawater is taken into the intake port as a medium-speed flow F1.

[0045] Here, if the flow rate of seawater at the intake port is high, for example, hard and dense foreign objects such as stones, metals, and shells that pass through the protective tube 90 will be sucked into the nozzle 70 according to the flow rate. If such foreign objects reach the intake pump 24, they may damage the impeller of the intake pump 24, and the foreign objects may clog the flow passages inside the intake pump 24, causing a malfunction of the intake pump 24.

[0046] In contrast, in this embodiment, the flow rate of seawater when it is sucked in from the water intake can be set to a medium flow rate F1, that is, the flow rate of seawater can be kept relatively low. This makes it possible to prevent foreign matter with high density from being sucked in from the water intake. As a result, it is possible to prevent malfunctions of the water intake pump 24.

[0047] Then, the seawater that has passed through the non-acceleration region R1 in the lower tubular portion 71 flows upward through the flow path in the upper tubular portion 72. At this time, since the flow path inside the upper tubular portion 72 is tapered so that the diameter decreases toward the top, the flow velocity of the seawater increases for the first time at this point, and a high-speed flow F2 is generated. In other words, the flow path in the upper tubular portion 72 is an acceleration region R2 that increases the flow velocity of the seawater.

[0048] The seawater thus accelerated to become the high-speed flow F2 enters the water intake pipe 60 while maintaining that speed, and flows upward inside the water intake pipe 60 to reach the water intake pump 24. Here, the seawater contains many microscopic marine organisms such as shellfish, barnacles, and larvae of sea slugs. If such marine organisms attach to the inside of the intake pipe 60, they will eventually erode the cross-sectional area of ​​the intake pipe 60 and reduce the intake performance of seawater. In addition, a lot of effort is required to remove them.

[0049] In contrast, in this embodiment, the flow rate of seawater is made high-speed flow F2 in the upper cylindrical portion 72 of the nozzle 70, and as a result, the flow rate of seawater in the water intake pipe 60 is maintained high. Therefore, microscopic marine organisms do not adhere to the inner circumferential surface of the water intake pipe 60, but are transported by the high-speed flow F2 to the water intake pump 24. Since it is possible to prevent marine organisms from remaining on the inner circumferential surface of the water intake in this way, it is possible to prevent the water intake from becoming clogged and reduce the frequency of maintenance.

[0050] As described above, in this embodiment, by reducing the flow velocity at the water intake, the suction of high-density foreign matter is suppressed, thereby avoiding malfunctions of the water intake pump 24, while by maintaining a high flow velocity within the water intake pipe 60, blockage of the water intake pipe 60 can be prevented. In addition, many shellfish, barnacles, and sea lions live on the side surface 5b of the breakwater 5, and many microscopic marine organisms that are the larvae of these organisms are also present in the seawater. In this embodiment, seawater is taken in from a location close to the side surface 5b of the breakwater 5, and the above configuration makes it possible to prevent clogging of the water intake pipe 60 even if there are many larvae.

[0051] Here, the filter 34, which finally removes minute impurities from seawater, easily becomes clogged, and is the one that requires the most frequent maintenance among various devices and equipment. In addition, since the radiation detection unit 35 is a precision machine, the seawater that is introduced into the radiation detection unit 35 needs to have the final impurities removed by the filter 34 immediately before it is introduced. Therefore, the filter 34 and the radiation detection unit 35 are usually arranged adjacent to each other as a set. Under such circumstances, if the filter 34 and the radiation detection unit 35 are arranged on the water intake facility 20 side at the end of the breakwater 5, the worker needs to frequently go to the end of the breakwater 5 by walking or by vehicle V. Depending on the weather, there is a risk of wind and high tide, so it is preferable to minimize the frequency of going to the end of the breakwater 5.

[0052] In contrast, in this embodiment, the water pipe 41 as the installation member 40 is arranged along the breakwater 5, which makes it possible to arrange the filter 34 and the radiation detection unit 35 on land. Therefore, workers do not need to go to the tip of the breakwater 5 every time they perform frequent maintenance on the filter 34. This makes it possible to significantly reduce the labor of the workers, and to perform maintenance while ensuring the safety of the workers.

[0053] Second Embodiment Next, a second embodiment of the present disclosure will be described with reference to Fig. 8. The second embodiment differs from the first embodiment in the configuration of a dividing plate 80 of a nozzle 70.

[0054] That is, in the second embodiment, the dividing plate 80 is provided in a lattice pattern in the region inside the lower cylinder portion 71 when viewed from the top-bottom direction. That is, the dividing plate 80 is configured by combining a plurality of plates so as to be perpendicular to each other when viewed from the top-bottom direction.

[0055] This also makes it possible to divide the area inside the lower cylindrical portion 71 into a plurality of small areas. Therefore, it is possible to suppress the generation of a large vortex, for example, centered on the axis O, inside the lower cylindrical portion 71. Therefore, similarly to the first embodiment, it is possible to reduce the flow velocity of seawater taken in from the water intake port at the lower end of the nozzle 70, and it is possible to prevent foreign matter with high density from being sucked in.

[0056] <Third embodiment> Next, a second embodiment of the present disclosure will be described with reference to Figures 9 and 10. The third embodiment includes a platform 100 and an elevator unit 120 provided around a protective tube 90 in addition to the configuration of the other embodiments.

[0057] A pair of mounts 100 are provided to surround the protective cylinder 90 from the horizontal direction along the side surface 5b of the breakwater 5. Each mount 100 has a horizontal base 110 installed to protrude from the side surface 5b of the breakwater 5. The upper surface of the horizontal base 110 is a flat surface parallel to the horizontal plane.

[0058] The platform 100 is installed below the top end 5a of the breakwater 5, at a height corresponding to the portion of the protective tube 90 above sea level. The object is supported by a horizontal support part 111 fixed to the side surface 5b of the breakwater 5 and projecting horizontally, and an inclined support part 112 fixed to a portion of the side surface 5b of the breakwater 5 below the horizontal support part 111 and extending at an angle upward as it projects horizontally.

[0059] A pair of lifting units 120 are provided corresponding to each mount 100. The lifting units 120 are fixed to the side surface 5b of the breakwater 5, and are provided at horizontal positions corresponding to each mount 100. The lifting units 120 are, for example, ladders fixed to the side surface 5b of the breakwater 5. The lifting units 120 may also be configured as stairs or the like.

[0060] According to this embodiment, a worker can descend from the top end 5a of the breakwater 5 onto the horizontal platform 110 of the frame 100 via the lifting unit 120. Using the horizontal platform 110 as a foothold, the worker can perform work such as removing foreign matter from the outer surface of the protective tube 90 and maintaining the water intake pipe 60. After completing the work, the worker can ascend to the top end 5a of the breakwater 5 via the lifting unit 120.

[0061] In this way, by providing a stand 100 for performing frequently performed maintenance tasks and a lifting section 120 for moving between the stand 100, there is no need to install separate scaffolding, etc., and maintenance work can be performed quickly and easily.

[0062] <Other embodiments> Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of the present disclosure are also included.

[0063] For example, the configuration of the dividing plate 80 of the nozzle 70 is not limited to the configurations described in the first and second embodiments, and other configurations may be adopted. In the first embodiment, the dividing plate 80 is divided into four sector shapes, but it may be divided into two or three, or may be divided into five or more shapes. Moreover, it is not limited to a lattice shape as in the second embodiment, and it may be divided into any shape.

[0064] <Additional Notes> The seawater sampling system 10 according to this embodiment can be understood as follows. (1) The seawater sampling system 10 is a seawater sampling system 10 for monitoring radiation concentrations in the sea area around a nuclear power plant, and includes a water intake facility 20 provided at the tip of a breakwater 5 extending from land 1 toward the ocean 2. The water intake facility 20 includes a water intake pump 24 provided at the breakwater 5, a water intake pipe 60 connected to the water intake pump 24 and extending below the water surface of the ocean 2, and a nozzle 70 connected to the lower end of the water intake pipe 60. The nozzle 70 includes a lower cylindrical portion 71 having a cylindrical shape extending uniformly in the vertical direction and a lower end serving as a seawater intake port, an upper cylindrical portion 72 connected to the upper end of the lower cylindrical portion 71 and tapering in diameter as it extends upward and is connected to the lower end of the water intake pipe 60, and a dividing plate 80 provided within the lower cylindrical portion 71 and extending in the vertical direction, dividing the area within the lower cylindrical portion 71 into multiple portions when viewed in the vertical direction.

[0065] This makes it possible to keep the flow rate of seawater drawn in through the intake relatively low, thereby preventing foreign matter with high density from being drawn in through the intake. On the other hand, the flow rate of the seawater increases while it flows through the upper cylindrical portion 72. Therefore, the adhesion of minute marine organisms to the inner surface of the water intake pipe 60 can be suppressed.

[0066] The seawater sampling system 10 of (2) is the seawater sampling system 10 of (1) in which the lower cylindrical portion 71 and the upper cylindrical portion 72 are cylindrical with an axis O extending in the vertical direction as their center, and the dividing plate 80 is arranged radially around the axis O when viewed from the vertical direction.

[0067] This makes it possible to suppress the generation of vortexes centered on the axis O inside the lower cylindrical portion 71. Therefore, the flow speed of the seawater sucked into the lower cylindrical portion 71 can be more appropriately suppressed.

[0068] The seawater sampling system 10 of (3) is the seawater sampling system 10 of (1) in which the lower cylindrical portion 71 and the upper cylindrical portion 72 are cylindrically shaped centered on an axis O extending in the vertical direction, and the dividing plate 80 is arranged in a lattice pattern when viewed from the vertical direction.

[0069] This also makes it possible to suppress the generation of vortexes centered on the axis O inside the lower cylindrical portion 71. Therefore, the flow velocity of seawater sucked into the lower cylindrical portion 71 can be more appropriately suppressed.

[0070] The seawater sampling system 10 of (4) is any one of the seawater sampling systems 10 of (1) to (3) in which the dividing plate 80 extends over the entire range of the lower cylindrical portion 71 in the up-down direction.

[0071] This makes it possible to reliably reduce the flow velocity over the entire area of ​​the lower cylindrical portion 71 in the vertical direction.

[0072] (5) The seawater sampling system 10 is any of the seawater sampling systems 10 of (1) to (4), further comprising a protective tube 90 that surrounds the water intake pipe 60 and the nozzle 70 in the vertical direction and has a plurality of holes 90a formed therein that penetrate from the inside to the outside.

[0073] This makes it possible to prevent seaweed such as wakame seaweed and cloth-like foreign objects such as plastic bags from being sucked in through the nozzle 70.

[0074] (6) The seawater sampling system 10 is a sampling system which is the seawater sampling system 10 of (5), comprising a platform 100 arranged adjacent to the protective tube 90 and extending horizontally from the side 5b of the breakwater 5, and a lifting section 120 which connects the top 5a of the breakwater 5 to the breakwater 5 in a manner that allows it to be raised and lowered.

[0075] If a cloth-like foreign object adheres to the outside of the protective tube 90, a worker can descend to the breakwater 5 via the lifting section 120 to remove the foreign object.

[0076] (7) The seawater sampling system 10 is any of the seawater sampling systems 10 of (1) to (6), further comprising an on-shore facility 30 provided on the land 1 and having a filter 34 for removing impurities from the seawater and a radiation detection unit 35 for detecting radiation in the seawater that has passed through the filter 34, a water supply pipe 41 extending along the breakwater 5 for transporting seawater taken in by the water intake facility 20 to the on-shore facility 30, and a power cable 42 extending along the breakwater 5 for connecting the water intake facility 20 and the on-shore facility 30.

[0077] Here, the filter 34, which removes impurities such as marine organisms from seawater, requires more frequent maintenance than other equipment. In this embodiment, since the filter 34 is provided on the land side, it is possible to reduce the frequency of dispatching to the water intake facility 20. [Explanation of symbols]

[0078] 1 land 2 ocean 3 bays 4 Open ocean 5 Breakwater 5a Top 5b side 6 Wave-dissipating zone 10 Seawater Sampling System 20 Water intake equipment 21 Water Intake Building 24 Intake Pump 25 Cyclone Separator 26 Sterilization equipment 27 Sedimentation tank 28 Water Pump 29 Power distribution and signal transmission / reception units 30 Land Facilities 31 Onshore Building 32 Buffer Tank 33 Sampler Pump 34 Filters 35 Radiation detection unit 36 Radiation monitoring equipment 37 Power supply section 40 Installation materials 41 Water pipe 42 Power and signal cables (power cables) 50 Cover member 60 Water intake pipe 60a Small diameter inner surface 70 Nozzles 71 Lower cylinder part 71a Large diameter inner surface 72 Upper cylinder part 72a Tapered inner surface 80 split plate 80a board surface 90 Protective tube 90a hole 100 Mount 110 Horizontal platform 111 Horizontal support 112 Inclined support part 120 Lifting section O axis F0 Low speed flow F1 Medium speed flow F2 High speed flow R1 non-acceleration region R2 acceleration area

Claims

1. A seawater sampling system for monitoring radiation concentrations in sea areas around a nuclear power plant, comprising: The facility is equipped with a water intake facility at the tip of a breakwater extending from land toward the ocean, The water intake facility includes: A water intake pump provided on the breakwater; a water intake pipe connected to the water intake pump and extending below the water surface of the ocean; A nozzle connected to a lower end of the water intake pipe; having The nozzle is A lower cylindrical portion having a cylindrical shape extending uniformly in the vertical direction and a lower end serving as a seawater intake port; an upper cylindrical portion connected to an upper end of the lower cylindrical portion and tapering upward to be connected to a lower end of the water intake pipe; a dividing plate provided in the lower cylinder portion, extending in a vertical direction, and dividing an area in the lower cylinder portion into a plurality of areas when viewed in the vertical direction; A seawater sampling system having

2. The lower cylinder portion and the upper cylinder portion are cylindrical and have an axis extending in a vertical direction as a center thereof. The seawater sampling system according to claim 1 , wherein the dividing plates are arranged radially about the axis when viewed from above and below.

3. The lower cylinder portion and the upper cylinder portion are cylindrical and have an axis extending in a vertical direction as a center thereof. The seawater sampling system according to claim 1 , wherein the dividing plates are arranged in a lattice pattern when viewed from above and below.

4. The seawater sampling system according to claim 1 , wherein the dividing plate extends over the entire vertical range of the lower cylindrical portion.

5. The seawater sampling system according to any one of claims 1 to 3, further comprising a protective tube that encloses the water intake pipe and the nozzle in the vertical direction and has a plurality of holes formed therein that penetrate from the inside to the outside.

6. A platform is provided adjacent to the protective cylinder and extends horizontally from a side surface of the breakwater; A lifting section that connects the top end of the breakwater and the breakwater so that the breakwater can be raised and lowered; The seawater sampling system of claim 5 .

7. a land facility provided on the land, the land facility having a filter for removing impurities from the seawater and a radiation detection unit for detecting radiation in the seawater that has passed through the filter; A water supply pipe extending along the breakwater and supplying seawater taken in by the water intake facility to the land facility; A power cable extending along the breakwater and connecting the water intake facility and the onshore facility; The seawater sampling system of claim 1 , further comprising:

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