JP5563909B2 - Leak detection device - Google Patents

Description

  The present invention relates to a leak detection device that detects leaked steam from a steam pipe.

  Detection of leaked steam from steam pipes in nuclear power plants and other plants is performed by placing a temperature detector near the ceiling of the room where multiple steam pipes are installed, and high temperature steam leaks from the pipes. It is common to detect leaked steam by detecting the temperature rise inside. However, although this method is effective for large steam leakage that hinders the operation of the plant, it has not been possible to identify a pipe that has caused steam leakage among a plurality of pipes.

  Therefore, a technology has been developed in which a thermometer is provided on the side peripheral surface of the steam pipe, and the surroundings are surrounded by a surrounding member, thereby detecting the leakage of steam for each pipe by the change in the measured value of the thermometer. (For example, refer to Patent Document 1).

  Furthermore, a technique has been developed in which the surroundings of a mechanical seal of a water pipe are surrounded by an enclosing member, leakage water is guided from the enclosing member to a conduit, and the amount of leakage is measured (for example, see Patent Document 2).

JP-A-5-18848 JP 2009-14477 A

  However, since the technique described in Patent Document 1 described above detects the leakage of steam by the change in the measured value of the thermometer, for example, the thermometer also measures the change in the temperature of the steam in the pipe, There was a possibility of misjudgment as leakage, and furthermore, although the presence or absence of steam leakage could be detected, the amount of steam leakage could not be measured accurately.

  In addition, since the technique described in Patent Document 2 described above guides leaked water to the conduit, the leak amount can be accurately measured. However, in order to apply this technique to the leak amount of high-pressure leaking steam, In addition, it is necessary to confine the leaked steam by the surrounding member that can withstand the pressure of the high-pressure leaked steam, and to condense all of the leaked steam into water, which is not practical.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a steam pipe leakage detection device that can determine the amount of steam leakage with a simple configuration.

  In order to achieve the above object, a leak detection device according to the present invention includes an enclosure member that surrounds the outer periphery of a steam pipe with a gap, and a condensed water that is provided at a lower portion of the enclosure member and condensed with leaked steam leaked from the steam pipe. A condensate discharge pipe for discharging from the surrounding member, a condensate flow meter for measuring the flow rate of the condensate discharged by the condensate discharge pipe, A residual steam discharge pipe that discharges from the surrounding member, and a calculation unit that calculates the flow rate of the leaked steam based on the flow rate of the condensed water measured by the condensate flow meter and the ratio of the leaked steam that is obtained in advance to the condensed water. It is characterized by that.

  ADVANTAGE OF THE INVENTION According to this invention, in the leak detection apparatus of a steam piping, the amount of steam leaks can be calculated | required with a simple structure.

1 is a schematic diagram of a leak detection apparatus according to a first embodiment of the present invention. Schematic of the leak detection apparatus which concerns on the 2nd Embodiment of this invention. Schematic of the leak detection apparatus which concerns on the 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below.

(First embodiment)
(Constitution)
Hereinafter, a leak detection apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of a leak detection apparatus according to the first embodiment of the present invention.

  The leak detection device 1 includes a surrounding member 2, a condensed water discharge pipe 3, a U-shaped pipe 4, a conduit 5, a condensed water flow meter 6, a calculation unit 7, a residual steam discharge pipe 8, and a shield 10. And the radiation detector 11.

  The surrounding member 2 is provided so as to surround the outer periphery of the steam pipe 100 with a gap. As the shape of the surrounding member 2, a cylindrical shape having a diameter larger than that of the steam pipe 100 is desirable, but other shapes are applicable as long as the outer periphery of the steam pipe 100 can be surrounded.

  One end of the condensed water discharge pipe 3 is connected to the cylindrical lower portion of the surrounding member 2 with the condensed water discharge pipe 3 being vertical. Further, a conduit 5 is connected to the other end of the condensed water discharge pipe 3 via a U-shaped pipe 4. The conduit 5 is disposed so as to be inclined so that the condensed water 120 from the U-shaped tube 4 can be discharged to the drain. In addition, when the surrounding member 2 is not cylindrical shape, the condensed water discharge pipe 3 is connected to the lower part of the surrounding member 2 which is a position which can discharge | emit the water which flows into the surrounding member 2. FIG.

  A condensed water flow meter 6 is arranged in the conduit 5 so that the flow rate of the condensed water 120 flowing through the conduit 5 can be measured. The calculation unit 7 is electrically connected to the condensed water flow meter 6 so that the measurement result of the condensed water flow meter 6 can be transmitted to the calculation unit 7.

  Further, the conduit 5 is provided with a shield 10 so as to shield the radiation from the steam pipe 100, and the radiation detector 11 is provided in the conduit 5 at a position where the radiation from the steam pipe 100 can be shielded by the shield 10. Be placed.

  One end of the residual steam discharge pipe 8 is connected to the upper part of the cylindrical side peripheral surface of the surrounding member 2 with the residual steam discharge pipe 8 being perpendicular thereto. The other end of the residual steam discharge pipe 8 is opened to the atmosphere to the pressure in the room where the steam pipe 100 is installed. When the surrounding member 2 is not cylindrical, it is desirable to connect the residual steam discharge pipe 8 to the top of the surrounding member 2, which is a position where steam that convects upward within the surrounding member 2 can be discharged.

(Function)
The operation of the first embodiment of the present invention will be described below. When the leaked steam 111 leaks from the leak location 110 in the steam pipe 100, a part of the leaked steam 111 is condensed and becomes condensed water 120 and flows down to the lower part of the surrounding member 2. The leaked steam 111 that has not been condensed convects as residual steam 121 to the upper portion of the surrounding member 2.

  The condensed water 120 that has flowed down to the lower portion of the surrounding member 2 is discharged out of the surrounding member 2 by the condensed water discharge pipe 3, and flows down in the conduit 5 through the U-shaped tube 4. On the other hand, the residual steam 121 convected to the upper part of the surrounding member 2 is discharged out of the surrounding member 2 by the residual steam discharge pipe 8.

  The condensed water flow meter 6 arranged in the conduit 5 measures the condensed water 120 flowing down the conduit 5 as flow rate data per unit time such as 10 seconds to 1 minute. The condensed water flow meter 6 transmits the flow rate data of the condensed water 120 to the calculation unit 7.

  Here, the calculating part 7 shall memorize | store the condensation rate from which the leaking vapor | steam 111 condenses into the condensed water 120 beforehand. This condensation rate is obtained in advance by experiments, calculations, etc., depending on the temperature of the leaked steam 111, that is, the temperature of the steam in the steam pipe 100, the temperature in the room where the steam pipe 100 is installed, the shape of the surrounding member 2, and the like. Is to be determined. For example, the condensation rate of the leaked steam 111 in the main steam pipe of the boiling water reactor is about 60%.

  The calculation unit 7 calculates the total amount of the leaked steam 111 per unit time using the condensation rate and the flow rate data of the condensed water 120 received from the condensed water flow meter 6. For example, when the condensation rate is 50% and the flow rate data of the condensed water 120 received from the condensed water flow meter 6 indicates 100 ml per minute, the total amount of the leaked steam 111 per minute is 100 in terms of water. X (100% / 50%) = 200 ml is calculated.

  Furthermore, the radiation detector 11 measures the radiation concentration of the condensed water 120 flowing down the conduit 5. At this time, since the radiation from the steam pipe 100 is shielded by the shielding object 10, the radiation concentration of the condensed water 120 can be measured without being affected by the radiation background near the steam pipe 100.

(effect)
According to the first embodiment of the present invention, even when the high-pressure leaking steam 111 is discharged into the surrounding member 2, the remaining steam 121 is surrounded by the surrounding member 2 by the residual steam discharge pipe 8 opened to the atmospheric pressure. Therefore, the condensate 120 can be collected and measured by the condensate flow meter 6 without using the enclosure member 2 as a sturdy casing that traps the high-pressure leaking steam 111. Further, the leakage steam 111 corresponding to the residual steam 121 discharged by the residual steam discharge pipe 8 is calculated by the calculation unit 7 using the condensation rate data, and is added to the flow rate of the condensed water 120. The flow rate in terms of water can be obtained.

  In addition, since the condensed water 120 is once accumulated in the U-shaped tube 4 by providing the U-shaped tube 4, and the condensed water 120 is discharged through the conduit 5, the pressure in the surrounding member 2 is high. Moreover, erroneous measurement of the condensed water flow meter 6 due to this pressure can be prevented.

  Furthermore, the radiation detector 11 can measure the radiation concentration of the condensed water 120 without being influenced by the radiation background near the steam pipe 100.

(Second Embodiment)
(Constitution)
Hereinafter, a leak detection apparatus according to a second embodiment of the present invention will be described with reference to FIG. The same parts as those of the leakage detection apparatus according to the first embodiment are denoted by the same reference numerals, and the description of the same configuration is omitted.

  FIG. 2 is a schematic view of a leak detection apparatus according to the second embodiment of the present invention. The second embodiment is different from the first embodiment in that a residual steam flow meter 20 is newly added so that the residual steam 121 can be measured in the residual steam discharge pipe 8 in addition to the configuration of the first embodiment. The residual steam flow meter 20 and the computing unit 7 are electrically connected so that the flow rate of the residual steam 121 measured by the residual steam flow meter 20 can be transmitted to the computing unit 7.

(Function)
The operation of the second embodiment of the present invention will be described below. Similar to the first embodiment, when the leaked steam 111 leaks from the leaked portion 110, the condensed water 120 that has flowed down to the lower portion of the surrounding member 2 is discharged out of the surrounding member 2 by the condensed water discharge pipe 3, and is U-shaped. It flows down in the conduit 5 via the tube 4. On the other hand, the residual steam 121 convected to the upper part of the surrounding member 2 is discharged out of the surrounding member 2 by the residual steam discharge pipe 8.

  The condensed water flow meter 6 measures the flow rate of the condensed water 120 flowing down the conduit 5 as flow rate data per unit time, and transmits the flow rate data of the condensed water 120 to the calculation unit 7.

  The residual steam flow meter 20 measures the flow rate of the residual steam 121 discharged out of the surrounding member 2 by the residual steam discharge pipe 8 as the same steam flow data per unit time as the condensed water flow meter 6, and this residual steam. The steam flow data 121 is transmitted to the calculation unit 7.

  Here, the calculating part 7 shall memorize | store the volume ratio when the volume of the residual vapor | steam 121 and the residual vapor | steam 121 condensed into water beforehand. Generally, since the volume of steam is about 1500 times that of water, the volume ratio is stored as 1/1500.

  The calculation unit 7 uses the flow rate data of the condensed water 120 received from the condensed water flow meter 6, the steam flow data of the residual steam 121 received from the residual steam flow meter 20, and the volume ratio to leak steam per unit time. 110 water equivalent flow rate is calculated. For example, when the flow rate data of the condensed water 120 indicates 100 ml per minute and the steam flow rate data of the residual steam 121 indicates 150,000 ml per minute, the total amount of the leaked steam 111 per minute is 100 + 150,000 × (1 / 1500) = 200 ml.

(effect)
According to the second embodiment of the present invention, even when the high-pressure leaking steam 111 is released into the surrounding member 2, the remaining steam 121 is surrounded by the surrounding member 2 by the residual steam discharge pipe 8 opened to the atmospheric pressure. Therefore, the condensate 120 can be collected and measured by the condensate flow meter 6 without using the enclosure member 2 as a sturdy casing that traps the high-pressure leaking steam 111. And the residual steam 121 discharged | emitted by the residual steam discharge pipe 8 is measured in the residual steam flow meter 20, and it converts into the flow volume of water by the volume ratio when the residual steam 121 condenses in water, By adding together, the water equivalent flow rate of the leaking steam 111 can be obtained.

(Third embodiment)
(Constitution)
Hereinafter, a leak detection apparatus according to a third embodiment of the present invention will be described with reference to FIG. The same parts as those of the leakage detection apparatus according to the first embodiment are denoted by the same reference numerals, and the description of the same configuration is omitted.

  FIG. 3 is a schematic diagram of a leak detection apparatus according to the third embodiment of the present invention. The third embodiment differs from the first embodiment in that an air conditioner 30 is provided instead of the residual steam discharge pipe 8. The air conditioner 30 is connected to the surrounding member 2 so that the air inside the surrounding member 2 is taken in, adjusted in temperature, and then sent into the surrounding member 2 again.

(Function)
The operation of the third embodiment of the present invention will be described below. The air conditioner 30 is operated so as to keep the temperature of the air inside the surrounding member 2 constant. For example, when the temperature of the air inside the surrounding member 2 rises above a predetermined temperature, the air conditioner 30 takes in the air inside the surrounding member 2 and cools it, then sends the air into the surrounding member 2 again, Operate to return to temperature.

  Similar to the first embodiment, when the leaked steam 111 leaks from the leaked portion 110, the condensed water 120 that has flowed down to the lower portion of the surrounding member 2 is discharged out of the surrounding member 2 by the condensed water discharge pipe 3, and is U-shaped. It flows down in the conduit 5 via the tube 4. On the other hand, the residual steam 121 convected to the upper part of the surrounding member 2 is taken into the air conditioner 30.

  The condensed water flow meter 6 measures the flow rate of the condensed water 120 flowing down the conduit 5 as flow rate data per unit time, and transmits the flow rate data of the condensed water 120 to the calculation unit 7.

  The air conditioner 30 takes in the air inside the surrounding member 2 including the residual steam 121, cools the temperature raised by the residual steam 121 to return to a predetermined temperature, and sends it back into the surrounding member 2 again. The residual vapor 121 condensed in the cooling process is discharged to the drain. Furthermore, the air conditioner 30 leaks the leaked steam 111 and cools the air inside the surrounding member 2 so as to return to a predetermined temperature. Is transmitted to the calculation unit 7.

  Here, the calculating part 7 shall memorize | store the steam temperature of the residual steam 121 previously. The steam temperature of the leaked steam 111 leaked from the steam pipe 100 can be determined by a thermometer, an operation program, or the like inside the plant. Furthermore, since the inside is kept warm by the surrounding member 2, the steam temperature of the residual steam 121 can be determined as a value equal to the steam temperature of the leaked steam 111.

  Here, since the relationship of cooling power amount = (power amount necessary for cooling the residual steam 121 having a unit flow rate of a certain steam temperature to a predetermined temperature) × (flow rate of the residual steam 121) is established, the calculation unit 7 Can calculate the steam flow rate data of the residual steam 121 per unit time using the cooling power amount and the steam temperature of the residual steam 121.

  For example, the steam temperature of the residual steam 121 is 80 ° C., and the amount of power required to cool the residual steam 121 to a predetermined temperature (40 ° C.) by 1000 ml is 1 W, and the cooling power amount per unit time Is 150 W, the steam flow rate of the residual steam 121 per unit time can be calculated as 1000 × 150 = 150,000 ml.

  Further, the calculation unit 7 converts the steam flow data of the residual steam 121 per unit time into water according to the volume ratio of the steam and water, and measures the unit time measured by the condensed water flow meter 6 as in the second embodiment. The flow rate of water equivalent of the leaked steam 111 per unit time is calculated by adding the flow rate data of the condensed water 120 per unit.

(effect)
According to the third embodiment of the present invention, even when the high-pressure leaking steam 111 is released into the surrounding member 2, the remaining steam 121 is cooled by the air conditioner 30 and the condensed steam is discharged to the drain. Therefore, the condensate 120 can be collected and measured by the condensate flow meter 6 and the residual steam 121 without the surrounding member 2 having a strong casing that traps the high-pressure leaking steam 111. Is converted into a flow rate of water based on the amount of power consumed by the air conditioner 30 and the temperature of the residual steam 121, and added to the flow rate of the condensed water 120, the net water equivalent flow rate of the leaked steam 111 can be obtained. .

  Needless to say, the embodiment of the present invention is not limited to the above-described embodiment. For example, in the first embodiment and the second embodiment, the other end of the residual steam discharge pipe 8 is not only opened to the atmosphere to the pressure in the room where the steam pipe 100 is installed, but also the residual steam discharge pipe 8. A pressure valve may be provided at the other end, and when the pressure in the surrounding member 2 becomes a certain level or more, the pressure valve may be opened and the residual steam 121 may be discharged through the residual steam discharge pipe 8.

  Further, the surrounding member 2 does not need to be provided around the entire steam pipe 100, and can be provided only in a portion where steam leakage is likely to occur, such as a joint portion of the two steam pipes 100, and the residual steam discharge pipe 8. Alternatively, the air conditioner 30 may be connected not only to the upper part of the surrounding member 2 but also to a plurality of side peripheral surfaces.

  Furthermore, not only can the water-converted flow rate of the leaking steam 111 be calculated, but the vapor-converted flow rate of the leaking steam 111 can be calculated using the volume ratio of water to steam.

  Moreover, when the flow rate of the leaked steam 111 calculated in the calculation unit 7 exceeds the reference value, an alarm device that notifies the operator of an alarm alarm may be further provided.

DESCRIPTION OF SYMBOLS 1 ... Leak detection apparatus 2 ... Enclosing member 3 ... Condensate drain pipe 4 ... U-shaped pipe 5 ... Conduit 6 ... Condensate flow meter 7 ... Calculation part 8 ... Residual steam discharge pipe 10 ... Shield 11 ... Radiation detector 20 ... Residual steam flow meter 30 ... Air conditioner 100 ... Steam pipe 110 ... Leakage point 111 ... Leakage steam 120 ... condensed water 121 ... residual steam

Claims (6)

An enclosing member that surrounds the outer periphery of the steam pipe with a gap;
A condensed water discharge pipe that is provided in a lower part of the surrounding member and discharges condensed water condensed from leaked steam leaked from the steam pipe from the surrounding member;
A condensate flow meter for measuring a flow rate of the condensed water discharged by the condensed water discharge pipe;
A residual steam discharge pipe that is provided in the surrounding member and discharges residual steam that has not been condensed out of the leaked steam from the surrounding member;
A calculation unit that calculates a flow rate of the leaked steam leaked from the steam pipe according to a flow rate of the condensed water measured by the condensed water flow meter and a ratio of the leaked steam that is obtained in advance to the condensed water. A leak detection apparatus comprising: An enclosing member that surrounds the outer periphery of the steam pipe with a gap;
A condensed water discharge pipe that is provided in a lower part of the surrounding member and discharges condensed water condensed from leaked steam leaked from the steam pipe from the surrounding member;
A condensate flow meter for measuring a flow rate of the condensed water discharged by the condensed water discharge pipe;
A residual steam discharge pipe that is provided in the surrounding member and discharges residual steam that has not been condensed out of the leaked steam from the surrounding member;
A steam flow meter for measuring a flow rate of the residual steam discharged by the residual steam discharge pipe;
Using the flow rate of the condensed water measured by the condensate flow meter and the flow rate of the residual steam measured by the steam flow meter, a calculation unit that calculates the flow rate of the leaked steam leaked from the steam pipe A leak detection apparatus comprising: An enclosing member that surrounds the outer periphery of the steam pipe with a gap;
A condensed water discharge pipe that is provided in a lower part of the surrounding member and discharges condensed water condensed from leaked steam leaked from the steam pipe from the surrounding member;
A condensate flow meter for measuring a flow rate of the condensed water discharged by the condensed water discharge pipe;
It is provided in the surrounding member, and is operated so as to discharge residual steam that has not been condensed out of the leaked steam from the surrounding member, and keeps the inside of the surrounding member at a predetermined temperature. An air conditioner that measures the amount of power required to return the temperature to
Using a flow rate of the condensate water measured by the condensate flow meter and an amount of electric power measured by the air conditioner, and a calculation unit for calculating a flow rate of the leaked steam leaked from the steam pipe. Leakage detection device characterized. A U-shaped pipe connected to the condensed water discharge pipe;
The leak detection device according to any one of claims 1 to 3, wherein the condensed water flow meter measures a flow rate of the condensed water discharged through the U-shaped tube.   A radiation detector is further provided at a position sufficiently lower than a radiation background near the steam pipe, and a radiation amount of the condensed water discharged from the condensed water discharge pipe is measured. 5. The leak detection device according to any one of claims 4.   The alarm device according to any one of claims 1 to 5, further comprising an alarm device for notifying an operator of an alarm alarm when the flow rate of the leaked vapor calculated in the arithmetic unit exceeds a reference value. Leak detection device.

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