Biological adhesion prevention device

Abstract

To provide a biofouling prevention device capable of achieving stable plant operation by preventing marine organisms from attaching.SOLUTION: The biofouling prevention device is a biofouling prevention device for preventing marine lives from adhering to an intake of a nuclear power plant located on the coast of the ocean. The biofouling prevention device includes: a first temperature measurement unit that is installed at the intake for measuring the temperature of seawater; an air bubble generator that is located at a deeper water depth than the intake and generates micro bubbles; and a control unit that is configured so as to, when the temperature measured by the first temperature measurement unit is higher than a first predefined threshold value, drive the air bubble generator.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an organism adhesion prevention device.

Background Art

[0002] In a nuclear power plant, water taken from a water source such as the ocean is used as cooling water for cooling a nuclear reactor. A water intake for taking in water is provided in the plant (see, for example, Patent Document 1 below). When the plant is located on a marine coast, marine organisms such as barnacles and green musses may adhere to the water intake along with long-term operation.

[0003] When the adhesion amount of such marine organisms increases, the flow path of the water intake is obstructed, the amount of water that can be taken in from the water intake decreases, and there is a risk that the stable operation of the plant may be hindered.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] However, conventionally, effective measures for preventing the adhesion of marine organisms as described above have not been taken, and the intake of cooling water cannot be performed smoothly, which has affected the operation of the plant in some cases.

[0006] The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide an organism adhesion prevention device that achieves stable operation of a plant by preventing the adhesion of marine organisms.

Means for Solving the Problem

[0007] To solve the above problems, the biofouling prevention device according to the present disclosure is a biofouling prevention device for preventing marine organisms from attaching to the water intake of a nuclear power plant located on the coast of the ocean, and comprises: a first temperature measuring unit provided at the water intake for measuring the temperature of seawater; a bubble generating device provided at a position deeper than the water intake for generating microbubbles; and a control unit that drives the bubble generating device when the temperature measured by the first temperature measuring unit is higher than a predetermined first threshold. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a biofouling prevention device that enables stable operation of a plant by preventing the attachment of marine organisms. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing the configuration of a biological fouling prevention device according to the first embodiment of this disclosure. [Figure 2] This is a schematic diagram showing the configuration of a bubble generator according to the first embodiment of this disclosure. [Figure 3] This is a functional block diagram of the control unit according to the first embodiment of this disclosure. [Figure 4] This is a flowchart showing the control flow of the control unit according to the first embodiment of this disclosure. [Figure 5] This is a schematic diagram showing the configuration of a biological fouling prevention device according to the second embodiment of this disclosure. [Figure 6] This is a flowchart showing the control flow of the control unit according to the second embodiment of this disclosure. [Figure 7] This is a schematic diagram showing the configuration of a biological fouling prevention device according to the third embodiment of this disclosure. [Figure 8] This flowchart shows the control flow of the control unit according to the third embodiment of this disclosure. [Figure 9] This is a schematic diagram showing the configuration of a biological fouling prevention device according to the fourth embodiment of this disclosure. [Figure 10]This is a flowchart showing the control flow of the control unit according to the fourth embodiment of this disclosure. [Figure 11] This figure shows the hardware configuration of the control unit according to each embodiment of the present disclosure. [Modes for carrying out the invention]

[0010] <First Embodiment> Hereinafter, the biological fouling prevention device 1 according to the first embodiment of this disclosure will be described with reference to Figures 1 to 4. This biological fouling prevention device 1 is a device for preventing marine organisms such as barnacles and green mussels from attaching to the water intake 90 of a nuclear power plant.

[0011] As shown in Figure 1, the intake 90 is a pipeline for drawing water from the ocean to be used as cooling water for the reactor, and its end is open to the ocean. The distance between the intake 90 and the various facilities that require cooling water is several hundred meters to about one kilometer. Although not shown in detail, the pipeline between these facilities and the intake 90 is equipped with ancillary equipment such as pumps, filters, and shut-off gates for pressurizing the water. The water depth at the location where the intake 90 is installed is about several meters.

[0012] (Configuration of biofouling prevention device 1) The biofouling prevention device 1 comprises a first temperature measuring unit 10, a bubble generating device 20, and a control unit 30. The first temperature measuring unit 10 is attached to the water intake 90. The first temperature measuring unit 10 measures the temperature of the seawater passing through the water intake 90 and transmits the value as an electrical signal to the control unit 30. In other words, the first temperature measuring unit 10 and the control unit 30 are electrically connected. Specifically, the first temperature measuring unit 10 can be a temperature sensor. It is also desirable to use a temperature sensor that is resistant to corrosion by seawater.

[0013] The bubble generator 20 is a device for raising deep seawater to the surface layer by generating microbubbles in seawater using compressed air. The bubble generator 20 is provided at an offshore position where the water depth is greater than that of the water intake 90. As shown in Fig. 2, the bubble generator 20 includes a compression unit 21 and a plurality of device main bodies 22. The compression unit 21 is provided, for example, on land. The compression unit 21 compresses atmosphere to generate compressed air. As the compression unit 21, a known rotating machine such as an axial flow compressor or a centrifugal compressor is used. Note that the compression unit 21 may be disposed on a ship anchored offshore or on a barge.

[0014] The device main body 22 is a tubular member communicating with the compression unit 21. A plurality of the device main bodies 22 are arranged at intervals from a shallow water depth position to a deep water depth position. A flow path through which compressed air circulates is formed inside the device main body 22. A large number of micropores (not shown) for ejecting compressed air to generate microbubbles are formed on the outer surface of the device main body 22. Furthermore, the deeper the position of the device main body 22, the greater the number of the pores. Alternatively, the deeper the position of the device main body 22, the larger the size and dimensions thereof are set. That is, the deeper the position of the device main body 22, the device is configured to generate more microbubbles. The device main body 22 may extend in the vertical direction as shown in Fig. 2, or may extend in a horizontal direction (not shown).

[0015] The control unit 30 controls the operation of the bubble generator 20 based on the temperature measured by the first temperature measurement unit 10. As shown in Fig. 3, the control unit 30 includes a temperature acquisition unit 31, a determination unit 32, a storage unit 33, and a drive unit 34. The temperature acquisition unit 31 acquires the seawater temperature at the water intake 90 input as an electrical signal from the first temperature measurement unit 10. The determination unit 32 compares the seawater temperature with a predetermined first threshold value. The first threshold value referred to herein means a low temperature sufficient to reduce the activity of marine organisms as described above. "Reduced activity" refers to a state in which marine organisms die or stop proliferating. The storage unit 33 stores the first threshold value in advance. The drive unit 34 issues a signal for driving and stopping the bubble generation unit based on the determination result of the determination unit 32.

[0016] When the determining unit 32 determines that the seawater temperature (first temperature) at the water intake 90 is higher than a first threshold, it can be determined that the activity of marine organisms tends to increase. Accordingly, the determining unit 32 instructs the driving unit 34 to transmit a signal for driving the bubble generator 20. When the driving unit 34 transmits the signal, the bubble generator 20 is driven to generate microbubbles in the sea.

[0017] Further, as the difference between the temperature measured by the first temperature measuring unit 10 and the first threshold becomes larger than a predetermined difference threshold, the control unit 30 preferentially drives the bubble generators 20 provided on the deeper side among the plurality of bubble generators 20.

[0018] As shown in FIG. 4, the control unit 30 first acquires the first temperature from the first temperature measuring unit 10 in step S1. Next, in step S2, the determining unit 32 compares the magnitude of the first temperature and the first threshold. If the determination in step S2 is No, the process returns to step S1 again. On the other hand, if the determination in step S2 is Yes, the driving unit 34 drives the bubble generator 20 (step S3). By driving the bubble generator 20, a large number of microbubbles are generated in the seawater. As the microbubbles rise due to buoyancy, low-temperature seawater in the deep layer rises toward the surface layer. As a result, the surface seawater temperature gradually decreases. Consequently, the activity of marine organisms is reduced, and the number of these marine organisms adhering to the water intake 90 is reduced.

[0019] (Effects) Here, when the adhesion amount of marine organisms such as barnacles and green musses described above increases, the amount of water that can be taken in from the water intake 90 decreases, which may hinder the stable operation of a plant. However, conventionally, effective measures for preventing the adhesion of such marine organisms have not been taken, which sometimes affected the operation of the plant. Therefore, the present embodiment adopts each configuration described above.

[0020] According to the above configuration, the water temperature (first temperature) at the water intake 90 is measured by the first temperature measurement unit 10. If the water temperature is higher than the first threshold, it can be determined that the activity of marine organisms tends to increase. Therefore, by driving the bubble generator 20, cold seawater from a layer deeper than the water intake 90 is brought up to the surface by bubbles. This lowers the seawater temperature near the water intake 90, making it possible to reduce the activity of marine organisms. As a result, the number of marine organisms attached to the water intake 90 can be reduced. In particular, by reducing the number of marine organism larvae during the winter, the proliferation of adults from spring onward can be effectively suppressed. As a result, it is possible to reduce the number of marine organisms attached to the water intake 90 throughout the year. Furthermore, since there is no need to use chemicals or other substances to reduce the number of marine organisms, the impact on the ecosystem can be minimized. Therefore, the plant can be operated stably without reducing the environmental performance of the plant.

[0021] Furthermore, with the above configuration, a large number of microbubbles can be formed inexpensively and stably simply by injecting compressed air from the micropores of the device body 22. In addition, since there is no need to use chemical products or drugs to generate bubbles, it is possible to minimize the environmental impact.

[0022] In the deep ocean offshore, the water pressure compresses the bubbles, reducing their volume. According to the above configuration, the high water pressure in the deep ocean allows for the generation of a relatively large number of bubbles, compensating for the volume reduction due to water pressure with increased bubble volume. This makes it possible to create a stable current of seawater flowing from the deep ocean to the surface. Consequently, the cold seawater from the deep ocean can be brought up to the surface more efficiently. As a result, the activity of marine organisms in the surface ocean can be effectively reduced.

[0023] Furthermore, if the difference between the seawater temperature at the intake 90 and the first threshold is greater than the difference threshold, it can be determined that a significant cooling of the seawater is necessary to inactivate marine organisms. Under these conditions, the bubble generator 20 located at a relatively deep depth is activated. This allows the cold seawater from the deep to rise to the surface, reducing the activity of marine organisms. On the other hand, if the difference with the first threshold is smaller than the difference threshold, it can be determined that a smaller reduction in seawater temperature is required to inactivate marine organisms. In this case, the bubble generator 20 located closer to the surface (shallower) is activated. This allows for economical operation of the bubble generator 20 according to the seawater temperature. In particular, when the system is configured to generate more microbubbles at deeper depths, as in this embodiment, the above configuration is advantageous from an economic standpoint.

[0024] The first embodiment of this disclosure has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of this disclosure.

[0025] <Second Embodiment> Next, a second embodiment of this disclosure will be described with reference to Figures 5 and 6. Components similar to those in the first embodiment are denoted by the same reference numerals, and detailed descriptions are omitted.

[0026] As shown in Figure 5, the biofouling prevention device 1 according to this embodiment further includes a second temperature measuring unit 110 in addition to the configuration described in the first embodiment. The second temperature measuring unit 110 is installed in seawater at a location spaced offshore from the water intake 90. It is desirable that the water depth at which the second temperature measuring unit 110 is installed is deeper than the water intake 90. The second temperature measuring unit 110 measures the seawater temperature in the area and transmits the value as an electrical signal to the control unit 30. In other words, this second temperature measuring unit 110 is also electrically connected to the control unit 30.

[0027] The control unit 30 controls the operation of the bubble generator 20 based on the seawater temperature at the intake 90 (first temperature) measured by the first temperature measurement unit 10, as well as the seawater temperature measured by the second temperature measurement unit 110 (second temperature). Specifically, the control unit 30 uses a determination unit 32 to drive the bubble generator 20 when the temperature measured by the second temperature measurement unit 110 is higher than the second threshold (which is lower than the first threshold), and the temperature measured by the first temperature measurement unit 10 is higher than the first threshold. In other words, by using offshore seawater temperature as an indicator in addition to the seawater temperature at the intake 90, it becomes possible to know the trend of seawater temperature over a wide area from the coast to the offshore. Therefore, it is possible to detect long-term trends in the number of marine organisms at an early stage.

[0028] As shown in Figure 6, the control unit 30 compares the magnitude of the first temperature and the first threshold in steps S1 and S2, similar to the first embodiment described above. Furthermore, in step S3, it obtains the second temperature from the second temperature measuring unit 110. Furthermore, in step S4, it determines whether the second temperature is higher than the second threshold. If it is determined to be No in step S4, it returns to step S1. On the other hand, if it is determined to be Yes in step S4, in the subsequent step S5, the bubble generator 20 generates microbubbles.

[0029] (Effects and Benefits) According to the above configuration, the seawater temperature at a location spaced offshore from the intake 90 is measured by the second temperature measurement unit 110. If this seawater temperature is higher than the second threshold and the seawater temperature at the intake 90 is higher than the first threshold, it can be determined that the temperature of the entire ocean surrounding the intake 90 is on an upward trend. In other words, it can be determined that the activity of marine organisms is likely to increase further. Therefore, when these conditions are met, the bubble generator 20 is driven to lower the surface seawater temperature. This makes it possible to reduce the activity of marine organisms. As a result, the number of marine organisms attached to the intake 90 can be further reduced. In this way, by detecting the trend of seawater temperature in an area extending offshore from the intake 90, it becomes possible to take measures to reduce the activity of marine organisms at an early stage, before they reach the intake 90 while still in the larval stage.

[0030] The second embodiment of this disclosure has been described above. It is possible to make various changes and modifications to the above configuration without departing from the gist of this disclosure.

[0031] <Third Embodiment> Next, a third embodiment of this disclosure will be described with reference to Figures 7 and 8. Components similar to those in the above embodiments are denoted by the same reference numerals, and detailed descriptions are omitted.

[0032] As shown in Figure 7, the biofouling prevention device 1 according to this embodiment further includes a third temperature measuring unit 210 in addition to the configuration described in the second embodiment. The third temperature measuring unit 210 is attached to the bubble generating device 20. In other words, the third temperature measuring unit 210 measures the seawater temperature (third temperature) at a location near the water intake 90 and at a depth greater than the water intake 90. The third temperature is transmitted as an electrical signal to the control unit 30. In other words, the third temperature measuring unit 210 is electrically connected to the control unit 30.

[0033] The control unit 30 drives the bubble generator 20 when the third temperature measured by the third temperature measurement unit 210 is higher than the third threshold (which is a temperature lower than the first threshold) and lower than the first threshold. Specifically, as shown in Figure 8, the control unit 30 executes steps S1 to S4 in the same manner as in the second embodiment, and then acquires the third temperature in step S5. Furthermore, in step S6, it determines whether the third temperature is higher than the third threshold. If it is determined to be No in step S6, it returns to step S1. On the other hand, if it is determined to be Yes in step S6, it is determined in the subsequent step S7 whether the third temperature is lower than the first threshold. If it is determined to be No in step S7, it returns to step S1. If it is determined to be Yes in step S7, it drives the bubble generator 20 in step S8 to generate microbubbles. In other words, by using the seawater temperature at a depth greater than the intake 90 as an indicator, in addition to the seawater temperature at the intake 90, it becomes possible to know the trend of seawater temperature over a wide range from the surface to the deep. Therefore, it is possible to detect long-term trends in the number of marine organisms at an early stage.

[0034] (Effects and Benefits) According to the above configuration, a third temperature measurement unit 210 is attached to the bubble generator 20. When the seawater temperature measured by the third temperature measurement unit 210 is higher than the third threshold and lower than the first threshold, the bubble generator 20 is activated. This makes it possible to reduce the activity of marine organisms at an early stage. As a result, the number of marine organisms attached to the water intake 90 can be further reduced. In this way, by detecting the rising or falling trend of seawater temperature in the depth direction, it becomes possible to take measures to reduce the activity of marine organisms at an early stage, before they reach the water intake 90 while they are still in the larval stage.

[0035] The third embodiment of this disclosure has been described above. It is possible to make various changes and modifications to the above configuration without departing from the gist of this disclosure.

[0036] <Fourth Embodiment> Next, a fourth embodiment of this disclosure will be described with reference to Figures 9 and 10. Components similar to those in the above embodiments are denoted by the same reference numerals, and detailed descriptions are omitted.

[0037] As shown in Figure 9, the biofouling prevention device 1 according to this embodiment further includes a fourth temperature measuring unit 410 in addition to the first temperature measuring unit 10 described in the first embodiment above. The fourth temperature measuring unit 410 is located between the water intake 90 and a pump room 91, which is provided on a pipeline extending from the water intake 90 toward the nuclear power plant. The pump room 91 is a space that houses a pump for pressurizing water in the pipeline. The pipeline continues downstream of the pump room 91. The fourth temperature measuring unit 410 measures the temperature of the seawater (fourth temperature) flowing in the region upstream of the pump room 91 in the pipeline and transmits the value as an electrical signal to the control unit.

[0038] The control unit 30 controls the operating state of the bubble generator based on the comparison result between the first temperature measured by the first temperature measurement unit 10 and the first threshold, as well as the comparison result between the temperature measured by the fourth temperature measurement unit 410 (fourth temperature) and a predetermined fourth threshold. The fourth threshold is a higher temperature than the first threshold. This is because the seawater is slightly warmed in the pipeline leading to the pump room 91 due to the influence of geothermal energy and waste heat from the pump room 91.

[0039] Specifically, the control unit 30, using the determination unit 32, drives the bubble generator 20 when the temperature measured by the first temperature measurement unit 10 is higher than the first threshold and the temperature measured by the fourth temperature measurement unit 410 is higher than the fourth threshold. In other words, by using the seawater temperature in the upstream area near the pump room 91 as an indicator in addition to the seawater temperature at the intake 90, it becomes possible to know the trend of seawater temperature over a wide area from the intake to the pump room. Therefore, it is possible to detect long-term trends in the number of marine organisms at an early stage.

[0040] As shown in Figure 10, the control unit 30 compares the magnitude of the first temperature and the first threshold in steps S1 and S2, similar to the first embodiment described above. Furthermore, in step S3, it obtains the fourth temperature from the fourth temperature measuring unit 410. Furthermore, in step S4, it determines whether the fourth temperature is higher than the fourth threshold. If it is determined to be No in step S4, it returns to step S1. On the other hand, if it is determined to be Yes in step S4, in the subsequent step S5, the bubble generator 20 generates microbubbles.

[0041] (Effects and Benefits) According to the above configuration, the seawater temperature upstream of the pump room 91, which is located inland from the water intake 90, is measured by the fourth temperature measuring unit 410. If this seawater temperature is higher than the fourth threshold and the seawater temperature at the water intake 90 is higher than the first threshold, it can be determined that the seawater temperature downstream of the water intake 90 is on an upward trend. In other words, it can be determined that the activity of marine organisms is likely to increase further. Therefore, when this condition is met, the bubble generator 20 is driven to lower the surface seawater temperature. This makes it possible to reduce the activity of marine organisms not only near the water intake 90 but also near the pump room 91. As a result, the number of marine organisms attached to the water intake 90 can be further reduced, and the possibility of marine organisms reaching the pump room 91 can also be reduced.

[0042] The fourth embodiment of this disclosure has been described above. It is possible to make various changes and modifications to the above configuration without departing from the gist of this disclosure.

[0043] <Other Embodiments> Although embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes and the like that do not depart from the gist of this disclosure.

[0044] For example, with respect to the control flow described in the second embodiment above, it is also possible to execute steps S1, S2 and steps S3, S4 in parallel. Furthermore, in this case, if either step S2 or step S4 is determined to be Yes, it is also possible to execute step S5 to drive the bubble generator 20.

[0045] Furthermore, although the above embodiments describe an example in which only one bubble generator 20 is provided, the number of bubble generators 20 is not limited to this, and multiple devices may be provided in each sea area. In addition, the dimensions, size, and number of bubble generators 20 can be freely changed according to the seabed topography and depth.

[0046] Furthermore, the bubble generator 20 can be configured not only to generate microbubbles but also to generate bubbles by jet injection. In this case as well, the same effects and benefits as described above can be obtained.

[0047] In addition, when a ship or other vessel is navigating the sea surface directly above the bubble generator 20 while it is in operation, it is desirable to temporarily stop the operation of the bubble generator 20. In this case, it is conceivable to install devices such as radar, sonar, or sensors on the sea surface and use the alarm from these devices as a trigger to stop the bubble generator 20.

[0048] Furthermore, the configuration of the water intake 90 described above is just one example, and various configurations are possible depending on the plant's location, design, and specifications.

[0049] Furthermore, the second temperature measurement unit 110 and the third temperature measurement unit 210 described above may be configured to be suspended in the sea from a buoy floating on the sea surface.

[0050] The above-described biofouling prevention device 1 may be operated year-round or only during specific periods. Since seawater temperature is at its lowest point of the year during winter, the activity of marine organisms decreases significantly. Therefore, it is desirable to focus the operation of the biofouling prevention device 1 during winter to reduce the absolute number of marine organisms early on. Continuing its operation through spring and summer thereafter will further reduce the activity and absolute number of marine organisms.

[0051] The types of marine organisms that can be targeted are not limited to those listed above; it is effective against any organism that has the property of attaching itself to walls or other surfaces.

[0052] Furthermore, regarding the operation of the control unit 30 described in the fourth embodiment, the fourth temperature measured by the fourth temperature measuring unit 410 does not necessarily need to be used as an indicator for determining whether to operate the bubble generator 20. In other words, if the distance from the water intake 90 to the pump chamber 91 is sufficiently long, the fourth temperature may be used merely as a reference, and the bubble generator 20 may be controlled by the first temperature measuring unit 10 and the control unit 30. Also, the second temperature measuring unit 110 described in the second embodiment may be used in combination with the first temperature measuring unit 10 and the fourth temperature measuring unit 410.

[0053] In addition, the processing of the control unit 30 in the embodiments of this disclosure may be performed in any order, as long as appropriate processing is performed.

[0054] Each of the storage unit 33 and other storage devices in the embodiments of this disclosure may be located anywhere within the scope of appropriate information transmission and reception. Furthermore, each of the storage unit 33 and other storage devices may be present in multiple locations within the scope of appropriate information transmission and reception, and data may be stored in a distributed manner.

[0055] The processing steps performed by the control unit 30 described above are stored in program format on a recording medium readable by the computer 300, and the above processing is carried out when the computer 300 reads and executes this program. A specific example of the computer 300 is shown below.

[0056] As shown in Figure 11, the computer 300 includes a CPU 301, main memory 302, storage 303, and interface 304. For example, the control unit 30 described above is implemented in the computer 300. The operation of each processing unit described above is stored in the storage 303 in the form of a program. The CPU 301 reads the program from the storage 303, loads it into the main memory 302, and executes the above processing according to the program. The CPU 301 also allocates a storage area in the main memory 302 corresponding to the storage unit 33 described above, according to the program.

[0057] Examples of storage 303 include HDDs (Hard Disk Drives), SSDs (Solid State Drives), magnetic disks, magneto-optical disks, CD-ROMs (Compact Disc Read Only Memory), DVD-ROMs (Digital Versatile Disc Read Only Memory), and semiconductor memory. Storage 303 may be an internal medium directly connected to the bus of computer 300, or an external medium connected to computer 300 via interface 304 or a communication line. Furthermore, if this program is distributed to computer 300 via a communication line, computer 300 may receive the program, expand it into main memory 302, and execute the above processing. Note that storage 303 is a tangible storage medium that is not temporary.

[0058] Furthermore, the above program may implement some of the functions described above. Moreover, the above program may be a file, a so-called differential file (differential program), that can implement the functions described above in combination with a program already recorded in the computer 300.

[0059] In addition to, or in place of, the above configuration may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device), an ASIC (Application Specific Integrated Circuit), a GPU (Graphics Processing Unit), and similar processing units. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions implemented by the processor may be implemented by the integrated circuit.

[0060] <Note> The biological fouling prevention device 1 described in each embodiment can be understood, for example, as follows:

[0061] (1) The first embodiment of the biofouling prevention device 1 is a biofouling prevention device 1 for preventing marine organisms from attaching to the water intake 90 of a nuclear power plant located on the coast of the ocean, and comprises: a first temperature measuring unit 10 provided at the water intake 90 for measuring the temperature of seawater; a bubble generating device 20 provided at a position deeper than the water intake 90 for generating microbubbles; and a control unit 30 that drives the bubble generating device 20 when the temperature measured by the first temperature measuring unit 10 is higher than a predetermined first threshold.

[0062] According to the above configuration, the water temperature at the intake 90 is measured by the first temperature measurement unit 10. If the water temperature is higher than the first threshold, it can be determined that the activity of marine organisms tends to increase. Therefore, by driving the bubble generator 20, cold seawater from a layer deeper than the intake 90 is brought up to the surface by bubbles. This lowers the seawater temperature near the intake 90, making it possible to reduce the activity of marine organisms. As a result, the number of marine organisms attached to the intake 90 can be reduced.

[0063] (2) The biofouling prevention device 1 according to the second embodiment is the biofouling prevention device 1 of (1), further comprising a second temperature measuring unit 110 provided at a position spaced offshore from the water intake 90 for measuring the temperature of seawater, wherein the control unit 30 drives the bubble generating device 20 when the temperature measured by the second temperature measuring unit 110 is higher than the second threshold, which is a temperature lower than the first threshold, and the temperature measured by the first temperature measuring unit 10 is higher than the first threshold.

[0064] According to the above configuration, the seawater temperature at a location spaced offshore from the water intake 90 is measured by the second temperature measurement unit 110. If this seawater temperature is higher than the second threshold, and the seawater temperature at the water intake 90 is higher than the first threshold, it can be determined that the temperature of the entire ocean around the water intake 90 is on an upward trend. In other words, it can be determined that the activity of marine organisms is likely to increase further. Therefore, when these conditions are met, the bubble generator 20 is driven to lower the surface seawater temperature. This makes it possible to reduce the activity of marine organisms. As a result, the number of marine organisms attached to the water intake 90 can be further reduced.

[0065] (3) The biological fouling prevention device 1 according to the third embodiment is the biological fouling prevention device 1 according to (1) or (2), further comprising a third temperature measuring unit 210 attached to the bubble generating device 20, wherein the control unit 30 drives the bubble generating device 20 when the temperature measured by the third temperature measuring unit 210 is higher than a third threshold which is a temperature lower than the first threshold, and lower than the first threshold.

[0066] According to the above configuration, a third temperature measuring unit 210 is installed alongside the bubble generator 20. When the seawater temperature measured by the third temperature measuring unit 210 is higher than the third threshold and lower than the first threshold, the bubble generator 20 is activated. This makes it possible to reduce the activity of marine organisms at an early stage. As a result, the number of marine organisms attached to the water intake 90 can be further reduced.

[0067] (4) The biofouling prevention device 1 according to the fourth embodiment is the biofouling prevention device 1 according to (1) or (2), further comprising a fourth temperature measuring unit 410 provided on a pipeline connecting the water intake 90 and a pump chamber 91 provided inland from the water intake 90, which measures the temperature of seawater flowing through the pipeline, and the control unit 30 drives the bubble generating device when the temperature measured by the fourth temperature measuring unit is higher than the fourth threshold, which is a temperature higher than the first threshold, and the temperature measured by the first temperature measuring unit is higher than the first threshold.

[0068] According to the above configuration, the seawater temperature upstream of the pump room 91, which is spaced inland from the water intake 90, is measured by the fourth temperature measuring unit 410. If this seawater temperature is higher than the fourth threshold and the seawater temperature at the water intake 90 is higher than the first threshold, it can be determined that the seawater temperature downstream of the water intake 90 is on an upward trend. In other words, it can be determined that the activity of marine organisms is on an upward trend. Therefore, when this condition is met, the bubble generator 20 is driven to lower the surface seawater temperature. This makes it possible to reduce the activity of marine organisms not only near the water intake 90 but also near the pump room 91.

[0069] (5) The fifth embodiment of the biofouling prevention device 1 is the biofouling prevention device 1 according to any one embodiment of (1) to (3), wherein the bubble generating device 20 comprises a compression unit 21 that generates compressed air, and a device body 22 that has a flow path through which the compressed air flows and a plurality of micropores from which the compressed air is ejected to the outside.

[0070] With the above configuration, a large number of microbubbles can be formed inexpensively and stably simply by injecting compressed air from the micropores of the device body 22.

[0071] (6) The biofouling prevention device 1 according to the sixth embodiment is a biofouling prevention device 1 according to any one embodiment of (1) to (5), comprising a plurality of bubble generating devices 20 provided at intervals in the depth direction, wherein the control unit 30 drives the bubble generating device 20 provided on the deeper side of the plurality of bubble generating devices 20 as the difference between the temperature measured by the first temperature measuring unit 10 and the first threshold becomes greater than a predetermined difference threshold.

[0072] According to the above configuration, if the difference between the seawater temperature at the intake 90 and the first threshold is greater than the difference threshold, it can be determined that a significant cooling of the seawater is necessary to inactivate marine organisms. Therefore, under such conditions, the bubble generator 20, which is installed at a relatively deep depth, is activated. This allows the cold seawater from the deep to rise to the surface, reducing the activity of marine organisms.

[0073] (7) The biological fouling prevention device 1 according to the seventh embodiment is the biological fouling prevention device 1 of (6), wherein the number of bubble generating devices 20 increases as the bubble generating device 20 is located at a deeper water depth.

[0074] In the deep sea, the bubbles are compressed by the water pressure. With the above configuration, in the deep sea where the water pressure is high, a relatively large number of bubbles are generated, making it possible to compensate for the decrease in bubble volume due to water pressure with the number of bubbles. This allows the cold seawater from the deep sea to rise to the surface more efficiently. [Explanation of Symbols]

[0075] 1…Anti-fouling device 10…First temperature measurement unit 20…Bubble generator 30…Control unit 21…Compression unit 22…Main unit 31…Temperature acquisition unit 32…Determination unit 33…Storage unit 34…Drive unit 90…Water intake 91…Pump room 110…Second temperature measurement unit 210…Third temperature measurement unit 300…Computer 301…CPU 302…Main memory 303…Storage 304…Interface 410…Fourth temperature measurement unit

Claims

1. A biofouling prevention device for preventing marine organisms from attaching to the water intake of a nuclear power plant located on the coast of the ocean, A first temperature measuring unit is provided at the aforementioned water intake for measuring the temperature of seawater, A bubble generating device that generates microbubbles is installed at a position deeper than the aforementioned water intake, A control unit that drives the bubble generator when the temperature measured by the first temperature measuring unit is higher than a predetermined first threshold, A biological fouling prevention device equipped with the following features.

2. It is further equipped with a second temperature measuring unit located at a position spaced offshore from the aforementioned water intake, for measuring the temperature of seawater, The biological fouling prevention device according to claim 1, wherein the control unit drives the bubble generator when the temperature measured by the second temperature measuring unit is higher than the second threshold, which is a temperature lower than the first threshold, and the temperature measured by the first temperature measuring unit is higher than the first threshold.

3. The bubble generator is further equipped with a third temperature measuring unit, The biological fouling prevention device according to claim 1 or 2, wherein the control unit drives the bubble generator when the temperature measured by the third temperature measuring unit is higher than a third threshold (a temperature lower than the first threshold) and lower than the first threshold.

4. The pipeline connecting the aforementioned water intake and a pump room located inland from the water intake is further provided with a fourth temperature measuring unit that measures the temperature of seawater flowing through the pipeline. The biological fouling prevention device according to claim 1 or 2, wherein the control unit drives the bubble generator when the temperature measured by the fourth temperature measuring unit is higher than the fourth threshold, which is a temperature higher than the first threshold, and the temperature measured by the first temperature measuring unit is higher than the first threshold.

5. The bubble generating device is A compression unit that generates compressed air, The apparatus body has a flow path through which the compressed air flows and a plurality of micro-holes from which the compressed air is ejected outwards, A biological fouling prevention device according to claim 1, having the following features.

6. The system is equipped with multiple bubble generating devices spaced apart in the depth direction, The biological fouling prevention device according to claim 1, wherein the control unit drives the bubble generating device located on the deeper side of the plurality of bubble generating devices as the difference between the temperature measured by the first temperature measuring unit and the first threshold becomes greater than a predetermined difference threshold.

7. The biological fouling prevention device according to claim 6, wherein the amount of bubbles generated increases as the bubble generating device is located at a deeper water depth.

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