JP2015031543A - Leakage detector and nuclear facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly and easily detect the leakage of a high-temperature fluid.SOLUTION: A leakage detector comprises: an outer plate 2 covering the outer periphery of a predetermined portion of secondary cooling water tubes 106a, 106b through which a high-temperature fluid flows; a heat insulator 3 filling between the secondary cooling water tubes 106a, 106b and the outer plate 2; a chamber 4 provided in a portion between the secondary cooling water tubes 106a, 106b and the outer plate 2 and formed with a space part S1 in which the heat insulator 3 is not disposed on the surfaces of the secondary cooling water tubes 106a, 106b; a temperature detection part 5 for detecting the temperature of the space part S1 of the chamber 4; and cooling means 6 for making a temperature detected by the temperature detection part 5 lower than that of the inside of the space part S1.

Description

  The present invention relates to a leakage detection device for monitoring leakage of a high-temperature fluid, and a nuclear facility to which the leakage detection device is applied.

  Conventionally, for example, Patent Document 1 discloses that in a nuclear power plant or other steam utilization facility, an abnormal steam leak alarm is automatically issued, so that a ceramic humidity sensor and a temperature sensor are insulated in a place where direct steam leak is predicted. Embedded in the material, the humidity and temperature data at that location is converted to absolute temperature by a microcomputer, and the presence or absence of an abnormality is judged based on the statistically processed data. An alarm is issued in the event of an abnormality. A steam leak warning system is described.

Japanese Patent Laid-Open No. 62-189596

  In the steam leak alarm system described in Patent Document 1 described above, a humidity sensor and a temperature sensor are embedded in a heat insulating material at a location where steam leak is predicted directly. For this reason, the humidity and temperature are detected by each sensor based on the humidity and temperature of the steam that has passed through the heat insulating material. It was difficult to take corrective actions. In addition, the steam leak alarm system described in Patent Document 1 is based on the data obtained by converting the humidity and temperature data into absolute temperatures using a microcomputer and performing statistical processing on these to determine whether there is an abnormality. And complex processing must be performed.

  The present invention solves the above-described problems, and an object of the present invention is to provide a leak detection apparatus and a nuclear facility that can quickly and easily detect a leak of a high-temperature fluid.

  In order to achieve the above-described object, the leak detection device of the present invention includes an outer plate that covers an outer periphery of a predetermined portion of a pipe through which a high-temperature fluid is circulated, and a heat insulating material that is filled between the pipe and the outer plate. And a room provided in a part between the pipe and the outer plate to form a space part on which the heat insulating material is not disposed on the surface of the pipe, and for detecting the temperature of the space part of the room And a cooling means for lowering the temperature detected by the temperature detection unit to be lower than the internal temperature of the space.

  According to this leak detection device, the temperature detected by the temperature detection unit by the cooling means is normally lower than the temperature of the room space by the cooling means, and the temperature of the room space rises when the high temperature fluid leaks. In association with this, the temperature detected by the temperature detection unit also rises, so that leakage of the high-temperature fluid can be detected.

  Further, in the leak detection device of the present invention, the cooling means is arranged to communicate with the inside and outside of the space portion of the room, and the tip that is formed in a cylindrical shape and is arranged inside the space portion is closed. A sheath tube made of a material having a high thermal conductivity is provided, and the temperature detection unit is arranged at a tip portion in the sheath tube.

  According to this leak detection device, the space portion of the room is normally heated by the heat of the high-temperature fluid transmitted from the surface of the pipe. On the other hand, since the sheath tube is made of a material having high thermal conductivity and is connected to the inside and outside of the space portion of the room, it is cooled by exchanging heat with the outside air outside the space portion, and accordingly, the inside of the space portion. The tip portion of the sheath tube disposed in the lower temperature than the space portion causes a temperature difference. And the temperature of the front-end | tip part of a sheath pipe is detected by the temperature detection part arrange | positioned at the front-end | tip part in this sheath pipe. For this reason, at the normal time when there is no leakage of the high-temperature fluid, the temperature detection unit detects the temperature of the distal end portion of the sheath tube that is lower than the space portion of the room. When a high-temperature fluid leaks, the heat input to the tip of the sheath tube increases due to convective heat transfer or condensation heat of the leaking steam, which increases the temperature of the tip of the sheath tube. Is detected by the temperature detector. As a result, leakage of the high temperature fluid can be detected.

  In the leak detection apparatus of the present invention, the sheath tube is characterized in that a portion arranged outside the space portion of the room is formed to have a larger outer diameter than the distal end portion.

  According to this leak detection device, the portion arranged outside the space portion of the room is formed with a large outer diameter with respect to the tip portion, so that the portion is exposed to the outside air outside the space portion. The heat exchange efficiency will be improved and cooling will be possible, the temperature drop at the tip part can be assisted, and the temperature difference with the space part can be made larger, so that leakage of high temperature fluid can be detected more quickly Can do.

  In the leak detection device of the present invention, the sheath tube is characterized in that a fin member is provided on an outer surface of a portion arranged outside the space portion of the room.

  According to the leak detection device, the fin member is provided on the outer surface of the portion arranged outside the space portion of the room, so that the heat exchange efficiency between the portion and the outside air is improved outside the space portion. As a result, the temperature of the tip portion can be reduced and the temperature difference from the space portion can be further increased, so that leakage of the high-temperature fluid can be detected more quickly.

  Further, in the leak detection device of the present invention, the cooling means is an annular shape that is arranged outside the space portion of the room and whose both ends communicate with the space portion of the room to naturally circulate the fluid inside the space portion of the room. A temperature detector is provided in the space part of the room, and the temperature detection part is arranged in a portion where the downstream end of the natural circulation of the annular pipe communicates with the space part of the room.

  According to this leak detection device, the space portion of the room is normally heated by the heat of the high-temperature fluid transmitted from the surface of the pipe. On the other hand, the downstream end side of the natural circulation of the annular pipe is cooled by exchanging heat with the outside air in the annular pipe, resulting in a lower temperature than the space and a temperature difference. And temperature is detected by the temperature detection part arrange | positioned in the downstream end of the natural circulation of this annular tube. For this reason, at a normal time when there is no leakage of the high-temperature fluid, the temperature detection unit detects a temperature lower than the space portion of the room. When a high-temperature fluid leaks, the temperature of the space in the room rises due to the convective heat transfer and condensation heat of the leaked steam, and the flow of the leaked steam into the space becomes dominant, and the flow from the annular pipe to the space Is not applied to the temperature detection unit, and the temperature detected by the temperature detection unit becomes very close to the temperature of the space. As a result, leakage of the high temperature fluid can be detected.

  In the leak detection device of the present invention, a fin member is provided on the outer surface of the annular tube.

  According to this leak detection device, by providing the fin member on the outer surface of the annular tube, the fluid passing through the annular tube is cooled with improved heat exchange efficiency with the outside air. Since the temperature decrease on the downstream end side due to natural circulation can be assisted and the temperature difference from the space can be made larger, leakage of the high temperature fluid can be detected more quickly.

  Further, the leak detection device of the present invention is characterized by comprising a feed mechanism for forcibly feeding the circulation of the fluid in the annular pipe.

  According to this leak detection device, the fluid passing through the annular pipe is cooled by improving the heat exchange efficiency with the outside air by providing the feed mechanism for forcibly feeding the circulation of the fluid in the annular pipe. Since the temperature decrease on the downstream end side due to the natural circulation of the annular pipe can be assisted and the temperature difference from the space can be increased, the leakage of the high temperature fluid can be detected more quickly.

  In order to achieve the above-described object, the nuclear power facility of the present invention is a nuclear power facility that generates a high-temperature fluid by heat generated in a nuclear reactor and sends it by piping, and uses the high-temperature fluid. The leak detection device described in one is applied.

  According to this nuclear facility, it is possible to quickly and easily detect the leakage of the high-temperature fluid, and to monitor the leakage of the high-temperature fluid in the nuclear facility.

  According to the present invention, leakage of a high-temperature fluid can be detected quickly and easily.

FIG. 1 is a schematic configuration diagram illustrating an example of a nuclear facility according to an embodiment of the present invention. FIG. 2 is a configuration diagram of the leak detection apparatus according to the first embodiment of the present invention. FIG. 3 is a configuration diagram of the leak detection apparatus according to the first embodiment of the present invention. FIG. 4 is a configuration diagram of a leak detection apparatus according to Embodiment 2 of the present invention. FIG. 5 is a configuration diagram of a leak detection apparatus according to Embodiment 2 of the present invention. FIG. 6 is a configuration diagram of a leak detection apparatus according to Embodiment 2 of the present invention.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is a schematic configuration diagram illustrating an example of a nuclear facility according to the present embodiment. The nuclear facility shown in FIG. 1 is a pressurized water reactor (PWR). In this nuclear power facility, a reactor pressure vessel 101, a pressurizer 102, a steam generator 103, and a primary cooling water pump 104 are sequentially connected by a primary cooling water pipe 105 in a reactor containment vessel 100 to circulate primary cooling water. The route is configured.

  The reactor pressure vessel 101 stores therein a plurality of fuel assemblies 101a, which are cores, in a sealed state, and a vessel body 101b and a vessel lid 101c mounted on the upper portion thereof so that the fuel assemblies 101a can be inserted and removed. It is comprised by. The container lid 101c is provided so as to be openable and closable with respect to the container main body 101b. The container main body 101b has a cylindrical shape with an upper opening and a lower hemispherical shape that is closed, and an inlet-side nozzle 101d and an outlet-side nozzle 101e that supply and discharge light water as primary cooling water are provided at the upper part. It has been. The outlet side nozzle 101e is connected to the primary cooling water pipe 105 so as to communicate with the inlet side water chamber 103a of the steam generator 103. The inlet side nozzle 101d is connected to the primary cooling water pipe 105 so as to communicate with the outlet side water chamber 103b of the steam generator 103.

  The steam generator 103 is provided with an inlet-side water chamber 103a and an outlet-side water chamber 103b partitioned by a partition plate 103c in a lower part formed in a hemispherical shape. The inlet side water chamber 103a and the outlet side water chamber 103b are separated from the upper side of the steam generator 103 by a tube plate 103d provided on the ceiling portion. On the upper side of the steam generator 103, an inverted U-shaped heat transfer tube 103e is provided. Each end of the heat transfer tube 103e is supported by the tube plate 103d so as to connect the inlet side water chamber 103a and the outlet side water chamber 103b. The inlet-side water chamber 103a is connected to the inlet-side primary cooling water pipe 105, and the outlet-side water chamber 103b is connected to the outlet-side primary cooling water pipe 105. In addition, the steam generator 103 is connected to the upper side upper end partitioned by the tube plate 103d, the outlet side secondary cooling water pipe 106a, and the upper side part is connected to the inlet side secondary cooling water pipe 106b. Has been.

  Further, in the nuclear power facility, the steam generator 103 is connected to the steam turbine 107 via the secondary cooling water pipes 106a and 106b outside the reactor containment vessel 100, and the circulation path of the secondary cooling water is configured.

  The steam turbine 107 includes a high-pressure turbine 108 and a low-pressure turbine 109, and a generator 110 is connected thereto. In addition, the high-pressure turbine 108 and the low-pressure turbine 109 are connected to a moisture separation heater 111 that is branched from the secondary cooling water pipe 106a. The secondary cooling water pipe 106 a is provided with a steam isolation valve (open / close valve) 119 on the way from the steam generator 103 to the high pressure turbine 108 and the low pressure turbine 109. The steam isolation valve 119 is closed in an emergency or the like, and the steam from the steam generator 103 to the high pressure turbine 108 and the low pressure turbine 109 is isolated. The low pressure turbine 109 is connected to the condenser 112. The condenser 112 is connected to the secondary cooling water pipe 106b. The secondary cooling water pipe 106b is connected to the steam generator 103 as described above, and reaches from the condenser 112 to the steam generator 103, and the condensate pump 113, the low-pressure feed water heater 114, the deaerator 115, and the main feed water pump. 116, a high-pressure feed water heater 117 and a main feed water valve (open / close valve) 118 are provided.

  Therefore, in the nuclear power facility, the primary cooling water is heated in the reactor pressure vessel 101 to become a high temperature and a high pressure, and is pressurized by the pressurizer 102 to maintain the pressure constant, while the steam is passed through the primary cooling water pipe 105. It is supplied to the generator 103. In the steam generator 103, heat exchange between the primary cooling water and the secondary cooling water is performed, whereby the secondary cooling water evaporates and becomes steam. The cooled primary cooling water after heat exchange is recovered to the primary cooling water pump 104 side via the primary cooling water pipe 105 and returned to the reactor pressure vessel 101. On the other hand, the secondary cooling water converted into steam by heat exchange is supplied to the steam turbine 107. In connection with the steam turbine 107, the moisture separator / heater 111 removes moisture from the exhaust from the high-pressure turbine 108, further heats it to an overheated state, and then sends it to the low-pressure turbine 109. The steam turbine 107 is driven by the steam of the secondary cooling water, and the power is transmitted to the generator 110 to generate power. Steam used for driving the turbine is discharged to the condenser 112. The condenser 112 exchanges heat between the cooling water (for example, seawater) taken by the pump 112b through the intake pipe 112a and the steam discharged from the low-pressure turbine 109, and condenses the steam to produce a low-pressure saturated liquid. Return to. The cooling water used for heat exchange is discharged from the drain pipe 112c. Further, the condensed saturated liquid becomes secondary cooling water, and is sent out of the condenser 112 by the condensate pump 113 through the secondary cooling water pipe 106b. Further, the secondary cooling water passing through the secondary cooling water pipe 106b is heated by the low-pressure feed water heater 114, for example, by the low-pressure steam extracted from the low-pressure turbine 109, and dissolved oxygen and non-condensed gas (ammonia gas) in the deaerator 115. After the impurities such as) are removed, the water is fed by the main feed pump 116 and heated by the high-pressure steam extracted from the high-pressure turbine 108 by the high-pressure feed water heater 117 and then returned to the steam generator 103. Here, a system for supplying secondary cooling water to the steam generator 103 is referred to as a main water supply system. In the main water supply system, the main water supply pump 116, the main water supply valve 118, and the like are controlled in order to maintain the water level of the secondary cooling water of the steam generator 103.

[Embodiment 1]
2 and 3 are configuration diagrams of the leak detection apparatus according to the present embodiment. The leak detection device 1 of the present embodiment is applied to the nuclear facility as described above. For example, the leak detection device 1 is disposed in the secondary cooling water pipes 106a and 106b that are pipes through which the secondary cooling water that is a high-temperature fluid is circulated in a nuclear power facility. Specifically, in the secondary cooling water pipe 106a, the leak detection device 1 includes a part immediately after being pulled out of the partition wall 100a of the reactor containment vessel 100, a welded connection part at a pipe fixing point, or a device (steam generator 103). , High pressure turbine 108, low pressure turbine 109, moisture separator / heater 111, and steam isolation valve 119). Further, in the secondary cooling water pipe 106b, the leak detection device 1 includes a part immediately after being pulled out of the partition wall 100a of the reactor containment vessel 100, a welded connection part at a pipe fixing point, or a device (steam generator 103, It arrange | positions at the welding connection part with the water machine 112, the condensate pump 113, the low pressure feed water heater 114, the deaerator 115, the main feed water pump 116, the high pressure feed water heater 117, and the main feed water valve 118). FIG. 2 shows a form in which the leakage detection device 1 is arranged immediately after the secondary cooling water pipes 106a and 106b are drawn out of the partition wall 100a of the reactor containment vessel 100, and FIG. The form which the leak detection apparatus 1 has been arrange | positioned to the welding connection part of the cooling water pipes 106a and 106b is shown. The leak detection device 1 may be disposed at each weld connection portion in the primary cooling water pipe 105 that is a pipe through which the primary cooling water that is a high-temperature fluid is circulated in the nuclear power facility. Moreover, the leak detection apparatus 1 which concerns on this embodiment is applied not only to a nuclear installation but piping which distribute | circulates a high temperature fluid. Moreover, the high temperature fluid from which leakage is detected by the leakage detection apparatus 1 according to the present embodiment includes liquids such as high temperature water and gases such as steam.

  In FIG. 2, the secondary cooling water pipes 106a and 106b are inserted into the protective pipe 100b at the partition wall 100a. The secondary cooling water pipes 106a and 106b drawn out of the partition wall 100a of the reactor containment vessel 100 are covered with an outer plate 2 whose outer periphery is connected to the protective pipe 100b. The outer plate 2 is formed of a steel plate or the like. A heat insulating material 3 is filled between the secondary cooling water pipes 106 a and 106 b and the outer plate 2. For this reason, steam and high-temperature water, which are high-temperature fluids circulated through the secondary cooling water pipes 106a and 106b, are protected by the protective pipe 100b and the outer plate 2 and kept warm by the heat insulating material 3.

  Further, in FIG. 3, in the welded connection portion 106c of the secondary cooling water pipes 106a and 106b (the welded connection portion with the device in FIG. 3), the device side has an outer plate 120 for protecting the device and a heat retaining member. It is covered with a heat insulating material 121. The secondary cooling water pipes 106 a and 106 b are covered with an outer plate 2 whose outer periphery is connected to the outer plate 120. The outer plate 2 is formed of a steel plate or the like. A heat insulating material 3 is filled between the secondary cooling water pipes 106 a and 106 b and the outer plate 2. For this reason, steam and high-temperature water, which are high-temperature fluids flowing through the secondary cooling water pipes 106a and 106b, are protected by the outer plate 2 and kept warm by the heat insulating material 3.

  As shown in FIG. 2 and FIG. 3, the leak detection device 1 of the present embodiment is configured such that the secondary cooling water pipes 106 a and 106 b and the outer plate 2 are formed in the large-diameter portion 21 where the outer diameter of the outer plate 2 is large. Between the room 4 formed with a sealed space S1 in which the heat insulating material 3 is not disposed on the surfaces of the secondary cooling water pipes 106a and 106b, and a temperature detection unit 5 for detecting the temperature of the space S1 of the room 4. And a cooling means 6 for lowering the temperature detected by the temperature detection unit 5 below the internal temperature of the space S1. In the case of FIG. 3, the space portion S1 is formed at the position of the weld connection portion 106c of the secondary cooling water pipes 106a and 106b.

  The cooling means 6 includes a sheath tube 9. The sheath tube 9 is arranged to communicate with the inside and the outside of the space portion S1 of the room 4, and is formed of a material having a high thermal conductivity in which the tip portion 9a disposed in the space portion S1 is closed. . Examples of the material having a high thermal conductivity include copper having a higher thermal conductivity than the steel forming the outer plate 2. And the temperature detection part 5 is arrange | positioned at the front-end | tip part 9a in the sheath tube 9. As shown in FIG.

  Here, as the temperature detection unit 5, for example, a temperature measuring resistor (RTD: Resistance Temperature Detector) configured as the sensor unit 5a is applied. The sensor unit 5a is not limited to the resistance temperature detector, and any sensor unit that can detect the temperature may be used. In the temperature detection unit 5, the sensor unit 5 a is arranged at the distal end portion 9 a in the sheath tube 9, and the signal line 5 b is drawn out of the sheath tube 9 from the sensor unit 5 a through the inside of the sheath tube 9.

  That is, in the leak detection device 1 of the present embodiment, the space portion S1 of the room 4 is normally heated by the heat of the high-temperature fluid transmitted from the surfaces of the secondary cooling water pipes 106a and 106b. On the other hand, the sheath tube 9 is arranged through the inside and outside of the space portion S1 of the room 4 and is made of a material having a high thermal conductivity, so that it is cooled by exchanging heat with the outside air outside the space portion S1. The distal end portion 9a of the sheath tube 9 disposed inside the space S1 has a lower temperature than the space S1, and a temperature difference occurs. And the temperature of the front-end | tip part 9a of the sheath pipe | tube 9 is detected by the temperature detection part 5 arrange | positioned at the front-end | tip part 9a in this sheath pipe | tube 9. FIG. For this reason, the temperature of the distal end portion 9a of the sheath tube 9 that is lower than the space portion S1 of the room 4 is detected by the temperature detection unit 5 at normal times when there is no leakage of high-temperature fluid. When the high-temperature fluid leaks, the heat input to the distal end portion 9a of the sheath tube 9 increases due to convective heat transfer and condensation heat of the leaked steam, so that the temperature of the distal end portion 9a of the sheath tube 9 rises. This increased temperature is detected by the temperature detector 5. As a result, leakage of the high temperature fluid can be detected.

  For example, when the temperature detection unit 5 is arranged in the space S1 of the room 4, the temperature detection unit 5 detects the high temperature in the space S1 at normal times, and similarly the space part when a high temperature fluid leaks. Although the high temperature in S1 is detected, since the temperature difference between the normal time and the leakage time is small, it is difficult to detect the leakage. In particular, in the case of a minute leak, there is a possibility that this cannot be detected. In this regard, in the leakage detection device 1 of the present embodiment, the temperature of the distal end portion 9a of the sheath tube 9 that is lower than the temperature of the space portion S1 of the room 4 is normally detected, and the room 4 is detected when the high-temperature fluid leaks. Since the temperature of the distal end portion 9a of the sheath tube 9 that has risen as the temperature of the space portion S1 increases is detected, even a slight leak can be detected quickly.

  By the way, in the leak detection apparatus 1 of this embodiment, as shown in FIG.2 and FIG.3, as for the sheath tube 9, the base part 9b which is a part arrange | positioned outside the space part S1 of the room 4 is in the front-end | tip part 9a. On the other hand, it is preferable that the outer diameter is thick.

  The base portion 9b of the sheath tube 9 which is a portion disposed outside the space portion S1 of the room 4 is formed to have a thick outer diameter with respect to the tip portion 9a, so that the base portion 9b is located outside the space portion S1. As a result, the heat exchange efficiency with the outside air is improved and the cooling is further performed, the temperature drop of the tip 9a can be assisted, and the temperature difference with the space S1 can be further increased. It can be detected more quickly.

  Further, in the leak detection device 1 of the present embodiment, although not shown in the drawing, the sheath tube 9 is provided with a fin member on the outer surface of the base portion 9b that is a portion disposed outside the space portion S1 of the room 4. Preferably it is.

  Since the fin member is provided on the outer surface of the base portion 9b that is a portion disposed outside the space portion S1 of the room 4, the base portion 9b improves the efficiency of heat exchange with the outside air outside the space portion S1. As a result, the temperature of the front end portion 9a can be assisted, and the temperature difference from the space portion S1 can be further increased, so that leakage of the high-temperature fluid can be detected more quickly.

  By the way, in this embodiment, it is preferable that the sheath tube 9 is arrange | positioned above the space part S1 of the room 4. FIG. When the high temperature fluid leaks, the vapor rises above the space S1. For this reason, the leakage of the high-temperature fluid can be detected more quickly by arranging the sheath tube 9 on the upper side in the space S1 of the room 4. Further, the sheath tube 9 may be disposed on the lower side in the space S <b> 1 of the room 4. When the high-temperature fluid leaks, the condensate descends below the space S1. For this reason, the leakage of the high-temperature fluid can be detected more quickly by arranging the sheath tube 9 on the lower side in the space S1 of the room 4.

[Embodiment 2]
4 to 6 are configuration diagrams of the leak detection apparatus according to the present embodiment. In addition, the leak detection apparatus 1 of this embodiment differs in the structure of the cooling means 6 from the leak detection apparatus 1 of Embodiment 1 mentioned above, and the other structure is the same. Therefore, in the second embodiment described below, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted. Further, in FIG. 4, similarly to FIG. 2 for explaining the above-described first embodiment, the leakage detection device 1 is inserted into the portion immediately after the secondary cooling water pipes 106 a and 106 b are drawn out of the partition wall 100 a of the reactor containment vessel 100. The form which provided is shown. Moreover, in FIG. 5 and FIG. 6, the form which provided the leak detection apparatus 1 in the welding connection part with an apparatus similarly to FIG. 3 explaining Embodiment 1 mentioned above is shown.

  In the present embodiment, the cooling means 6 includes an annular tube 10. The annular tube 10 is disposed outside the space portion S1 of the room 4, and both ends 10a and 10b communicate with the space portion S1 of the room 4 to naturally circulate the fluid inside the space portion S1. The annular tube 10 has one end 10 a communicating with the upper side of the space part S <b> 1 of the room 4 and the other end 10 b communicating with the lower side of the space part S <b> 1 of the room 4. Since the space portion S1 is warmed by the high-temperature fluid flowing through the secondary cooling water pipes 106a and 106b, the warmed fluid rises and flows out from the space portion S1 to the outside from the one end 10a of the annular tube 10, and inside the annular tube 10 Then, it is cooled by the outside air, reaches the other end 10b of the annular tube 10 and flows into the space S1. Thereby, the fluid inside the space S <b> 1 naturally circulates through the annular pipe 10. And the temperature detection part 5 is arrange | positioned inside the space part S1 of the room 4, and the other end 10b which is the downstream end of the natural circulation of the annular pipe 10 leads to the space part S1.

  Here, as the temperature detection unit 5, for example, a temperature measuring resistor (RTD: Resistance Temperature Detector) configured as the sensor unit 5a is applied. The sensor unit 5a is not limited to the resistance temperature detector, and any sensor unit that can detect the temperature may be used. The temperature detection unit 5 is disposed in a portion where the sensor unit 5a is inside the space S1 of the room 4 and the other end 10b that is the downstream end of the natural circulation of the annular tube 10 communicates with the space S1, and from the sensor unit 5a A signal line 5 b is drawn out of the annular tube 10 through a part of the annular tube 10.

  That is, in the leak detection device 1 of the present embodiment, the space portion S1 of the room 4 is normally heated by the heat of the high-temperature fluid transmitted from the surfaces of the secondary cooling water pipes 106a and 106b. On the other hand, the other end 10b side, which is the downstream end of the natural circulation of the annular pipe 10, is cooled by exchanging heat with the outside air in the annular pipe 10, and becomes cooler than the space portion S1, resulting in a temperature difference. And temperature is detected by the temperature detection part 5 arrange | positioned in the downstream end of the natural circulation of this annular pipe 10. FIG. For this reason, the temperature detection part 5 detects the temperature lower than the space part S1 of the room 4 at the normal time when the high-temperature fluid does not leak. When the high-temperature fluid leaks, the temperature of the space S1 of the room 4 rises due to the convective heat transfer and condensation heat of the leaked steam, and the flow of the leaked steam into the space S1 becomes dominant, and the space from the annular pipe 10 is increased. The flow to the part S1 is not applied to the temperature detection part 5, and the temperature detected by the temperature detection part 5 is very close to the temperature of the space part S1. As a result, leakage of the high temperature fluid can be detected.

  For example, when the temperature detection unit 5 is arranged in the space S1 of the room 4, the temperature detection unit 5 detects the high temperature in the space S1 at normal times, and similarly the space part when a high temperature fluid leaks. Although the high temperature in S1 is detected, since the temperature difference between the normal time and the leakage time is small, it is difficult to detect the leakage. In particular, in the case of a minute leak, there is a possibility that this cannot be detected. In this respect, the leak detection device 1 of the present embodiment normally detects a temperature lower than the temperature of the space part S1 of the room 4, and when the high temperature fluid leaks, the temperature of the space part S1 of the room 4 increases. Since the temperature that increases with the detection is detected, even a slight leak can be detected quickly.

  By the way, in the leak detection apparatus 1 of this embodiment, it is preferable that the fin member 11 is provided in the outer surface of the annular pipe 10, as shown in FIG.

  By providing the fin member 11 on the outer surface of the annular tube 10, the fluid passing through the annular tube 10 is further cooled by improving the heat exchange efficiency with the outside air. Since the temperature drop on the downstream end side can be assisted and the temperature difference from the space portion S1 can be increased, leakage of the high-temperature fluid can be detected more quickly.

  Moreover, it is preferable that the leak detection apparatus 1 of this embodiment is provided with the feed mechanism 12 which forcibly feeds the circulation of the fluid in the annular pipe 10, as shown in FIG.

  The feed mechanism 12 is configured by a pump. By providing the feed mechanism 12 that forcibly feeds the circulation of the fluid in the annular pipe 10, the fluid passing through the annular pipe 10 is cooled with improved heat exchange efficiency with the outside air. Since the temperature decrease on the downstream end side due to the natural circulation of the gas can be assisted and the temperature difference from the space S1 can be further increased, the leakage of the high temperature fluid can be detected more quickly.

  By the way, the leak detection apparatus 1 of Embodiment 1 and Embodiment 2 described above is applied to the above-described nuclear facility illustrated in FIG. 1 that generates a high-temperature fluid by heat generated in a nuclear reactor and uses the high-temperature fluid. The

  According to this nuclear facility, it is possible to quickly and easily detect the leakage of the high-temperature fluid, and to monitor the leakage of the high-temperature fluid in the nuclear facility.

  In addition, although the nuclear equipment mentioned above demonstrated what used the pressurized water reactor (PWR: Pressurized Water Reactor), it is not this limitation. For example, although not clearly shown in the figure, it may be a nuclear facility using a boiling water reactor (BWR), and the leak detection device 1 described above uses steam generated in the boiling reactor. It can be applied to the detection of leakage of piping to be passed.

DESCRIPTION OF SYMBOLS 1 Leak detection apparatus 2 Outer plate 3 Heat insulating material 4 Room 5 Temperature detection part 6 Cooling means 9 Sheath pipe 9a Tip part 9b Base part 10 Annular pipe 10a One end 10b The other end 11 Fin member 12 Feed mechanism 106a, 106b Secondary cooling water pipe (Piping )
S1 space

Claims (8)

An outer plate covering the outer periphery of a predetermined portion of the pipe through which the high-temperature fluid is circulated;
A heat insulating material filled between the pipe and the outer plate;
A room formed in a part between the pipe and the outer plate and forming a space portion where the heat insulating material is not arranged on the surface of the pipe;
A temperature detector for detecting the temperature of the space of the room;
Cooling means for lowering the temperature detected by the temperature detection unit below the internal temperature of the space,
A leak detection apparatus comprising:   The cooling means includes a sheath tube made of a material having a high thermal conductivity, which is arranged in communication with the interior and exterior of the space portion of the room, is formed in a cylindrical shape, and has a closed end disposed inside the space portion. The leak detection device according to claim 1, further comprising: a temperature detection unit disposed at a distal end of the sheath tube.   The leak detection device according to claim 2, wherein a portion of the sheath tube that is disposed outside the space portion of the room is formed to have a thicker outer diameter than a tip portion.   The leak detection device according to claim 2 or 3, wherein the sheath tube is provided with a fin member on an outer surface of a portion disposed outside the space portion of the room.   The cooling means includes an annular pipe that is disposed outside the space portion of the room and whose both ends communicate with the space portion of the room and naturally circulates the fluid inside the space portion of the room. The leak detection device according to claim 1, wherein the temperature detection unit is arranged at a portion inside the portion where the downstream end of the natural circulation of the annular pipe communicates with the space of the room.   The leak detection device according to claim 5, wherein a fin member is provided on an outer surface of the annular tube.   The leak detection device according to claim 5, further comprising a feed mechanism that forcibly feeds the circulation of the fluid in the annular pipe. A nuclear facility that generates a high-temperature fluid by heat generated in a nuclear reactor and sends it by piping, and uses the high-temperature fluid.
A nuclear facility to which the leak detection device according to any one of claims 1 to 7 is applied.

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