JP5292424B2 - Power plant outlet sampling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sampling device having piping which achieves effect of preventing deposits in piping without change of water quality and takes a physical countermeasure for preventing deposits. <P>SOLUTION: The sampling device has piping which has a double pipe structure including an inner pipe 3 having a porous structure and an outer pipe 2. Sea water 1 or air 4 is caused to flow in the outer pipe 2 to produce a flow of sea water 1 or air 4 in the vicinity of a pipe wall of the inner pipe from the outer pipe 2 through the porous structure of the inner pipe 3, whereby deposition of marine organisms and sludge is prevented. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a seawater sampling device in the vicinity of a cooling seawater outlet in a power plant such as a nuclear power plant.

  In a power plant such as a nuclear power plant that uses seawater as plant cooling water, a water outlet sampling device that samples seawater at a cooling water outlet is installed in order to monitor the release of radioactive substances and the like outside the system. After being used in a nuclear power plant, the outlet sampling device pumps seawater released to nature again from the outlet with a sample pump and measures the radioactivity level in the seawater to determine whether radioactive substances are released outside the system. Monitoring.

  However, if marine organisms, including shellfish larvae floating in seawater, adhere to the inner wall of the outlet sampling device and breed, or if sludge in seawater stays in the pipe, the pipe will become clogged. May occur, making it impossible to sample seawater. In particular, marine organisms and sludge sucked into the pipe together with seawater by the sample pump are likely to adhere to the pipe pipe wall due to a decrease in the flow velocity near the pipe pipe wall and the generation of vortex flow. As a result, breeding of attached marine organisms and sludge accumulation may occur, which may cause blockage of the piping. Since sampled seawater is used to monitor the release of radioactive materials from nuclear power plants, sufficient sampling volume cannot be obtained if piping clogging occurs, and reliability for safe operation of nuclear power plants Can not be guaranteed.

  In the conventional example shown in FIG. 12, seawater 1 as a sample is constantly flowed at a flow rate of about 250 to 310 (l / min) through a pipe P having a diameter of about 50 mm by a sample pump 103 at a sample point 102 existing at the outlet 101. After being collected and passed through the sample outlet valve 108, it is returned again to the water outlet 107 at a position different from the water intake location. In the normal state, the sample collection valve 104 is closed, and all the seawater 1 is returned to the water outlet 107.

  On the other hand, when the radiation dose at the water outlet 101 increases, the water outlet detector 116 in the radiation detector protective tube 117 installed at the water outlet 101 detects an increase in the radiation dose, and the radiation dose is greater than a predetermined set value. When it becomes higher, a warning of “radiation monitor high” is issued from the outlet radiation monitor device 118, the outlet sample outlet valve 108 is automatically closed by the outlet radiation monitor device 118, and the sample collecting valve 104 is opened. A sample for manual analysis is collected in the sample collection container 105 in the tray 106. After that, the person in charge analyzes the sample for manual analysis in detail, and confirms whether or not radioactive substances are released from the plant and their contents. As shown in FIG. 12, the pipe P of the outlet sampling apparatus constantly passes the seawater 1 from the outlet 101, so marine organism larvae and sludge that enter from the outlet 101 directly connected to the sea May enter the pipe, and these may adhere to the pipe wall due to a decrease in flow velocity or generation of vortex.

  As background technology in this technical field, the burden on the environment is reduced by supplying chlorine to a small amount of seawater in a small-diameter seawater pipe, and the anode is not damaged and has a long life, and the electrolytic current is uniform. A flowing marine organism adhesion preventing electrolysis apparatus and an adhesion preventing method are known (see, for example, Patent Document 1).

  Further, a double pipe in which a Cu—Ni alloy marine product adhesion preventing inner pipe formed with a slit-shaped opening is inscribed is known (for example, see Patent Document 2).

  Furthermore, it is known that a porous layer is provided on the inner peripheral surface of a seawater conduit of a nuclear power plant, and hydrogen peroxide water is leached to prevent adhesion of marine organisms (see, for example, Patent Document 3). .

JP-A-11-90380 Japanese Patent Laid-Open No. 1-126494 JP 2004-167451 A

  As mentioned above, the outlet sampling device collects the seawater released from the outlet of the nuclear power plant as a sample and monitors the water quality of the sample in order to monitor the release of radioactive materials from the nuclear power plant. . Therefore, since the introduction of a device that changes the quality of seawater in the piping affects the components of the sample, as in Patent Document 1, an apparatus that involves water quality changes such as electrolysis and supply of chlorines, or Patent Document The apparatus for supplying hydrogen peroxide solution shown in 3 is not applicable to a water outlet sampling apparatus.

  Also, the adhesion prevention by the antifouling metal made of Cu-Ni alloy described in Patent Document 2 cannot prevent the flow of seawater near the pipe wall, and the sludge that may cause the pipe clogging adheres. Therefore, the countermeasure for preventing adhesion according to Patent Document 2 is insufficient to remove the cause of the piping blockage described in the background art.

  The present invention has a pipe, a sample pump, and a sample collection valve, takes sample seawater from the sample point of the cooling water outlet and returns it to the cooling water outlet, and in the middle of the pipe In the water outlet sampling device of the power plant that performs seawater sampling of the water outlet through the provided sampling valve, the pipe is constituted by a double pipe comprising an outer pipe and a porous inner pipe, and the sample is placed in the inner pipe. In addition, it is characterized by flowing seawater for use and introducing a fluid into the outer pipe to flow into the seawater in the inner pipe, thereby preventing marine organisms and sludge from adhering to the inner pipe wall.

  Moreover, in the water outlet sampling apparatus of the power plant, the fluid is made of air.

  Further, in the water outlet sampling apparatus of the power plant, an air supply source for supplying the air into the outer pipe is provided downstream in the flow direction of the sampling valve of the pipe.

  Further, in the water outlet sampling device of the power plant, an air supply source for supplying the air into the outer pipe is provided in the vicinity of the sample point.

  Furthermore, in the water outlet sampling apparatus of the power plant, the fluid is seawater collected from the water outlet.

  Furthermore, in the outlet sampling apparatus of the power plant, a seawater supply pump for supplying the seawater to the outer pipe is provided in the vicinity of the sample pump.

  Further, in the outlet sampling apparatus for a power plant, a seawater supply pump for supplying the seawater to the outer pipe is provided in the vicinity of the sample point.

  Further, in the water outlet sampling device of the power plant, the pipe is branched from the sample pump, and an outer pipe introduction valve and an inner pipe insertion valve are provided at each branch to divert seawater, respectively, and the outer pipe and the inner pipe are separated. It is characterized by supplying seawater to the pipe.

  Furthermore, in the outlet sampling apparatus of the power plant, the hole direction of the porous inner pipe is inclined with respect to the flow direction of the seawater flowing in the inner pipe with respect to the inner pipe axis direction, and the flow velocity in the vicinity of the inner wall of the inner pipe is set. It is characterized by increasing.

  Furthermore, in the water outlet sampling device of the power plant, the pore direction of the porous inner pipe is inclined with respect to the center of the inner pipe in the radial direction of the inner pipe, and the flow velocity in the vicinity of the inner wall of the inner pipe is increased. And

  Furthermore, in the water outlet sampling apparatus of the power plant, a filter for filtering seawater is provided at the outer pipe inlet.

  Further, the water outlet sampling device of the power plant is characterized in that a differential pressure detector for detecting a pressure difference between the outer pipe and the inner pipe is provided to detect clogging of the filter.

The present invention takes sample seawater from the sample point of the cooling water outlet and returns it to the cooling water outlet and samples the seawater at the outlet via a sample collection valve provided in the middle of the piping. in outlets sampling device of the power plant, constructed a double pipe comprising a pipe from the inner tube of the outer tube and the porous, seawater taken from outlets in co flowing sea water for the sample in the inner tube to the outer tube By introducing and flowing into the seawater in the inner pipe to prevent marine organisms and sludge from adhering to the inner pipe wall, the pipe blockage prevention effect without water quality change was realized, and physical adhesion prevention measures were taken A sampling device having piping can be provided .

It is a systematic diagram of the sampling apparatus by Example 1 of this invention. It is sectional drawing of the sampling apparatus by Example 1 and 2 of this invention. It is AA sectional drawing of FIG. 2A. It is a systematic diagram of the sampling apparatus by Example 2 of this invention. It is a systematic diagram of the sampling apparatus by Example 3 of this invention. It is sectional drawing of the sampling apparatus by Example 3 of this invention. It is a systematic diagram of the sampling apparatus by Example 4 of this invention. It is sectional drawing of the sampling device by Example 4 of this invention. It is a systematic diagram of the sampling apparatus by Example 5 of this invention. It is sectional drawing of the sampling device by Example 5 of this invention. It is sectional drawing of the sampling device by Example 6 of this invention. It is BB sectional drawing of FIG. 10A. It is a systematic diagram of the sampling apparatus by Example 7 of this invention. It is a systematic diagram of the conventional sampling apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the respective examples and the drawings.

  FIG. 1 is a system diagram of a sampling apparatus according to Embodiment 1 of the present invention. A compressor 109 that introduces air into the outer pipe of the pipe P made of a double pipe is installed downstream of the sample collection valve 104. Note that a gas cylinder may be used in place of the compressor 109 as equipment for introducing air.

  FIG. 2A is a cross-sectional view of the sampling device according to the first embodiment, and FIG. 2B is a cross-sectional view taken along the line AA in FIG. 2A. As described above, marine organisms adhere to the inner wall of the pipe or sludge stays due to the decrease in the flow velocity or the vortex near the pipe wall, so the pipe P on the downstream side of the sample pump 103 is shown in FIGS. 2A and 2B. A pipe having a double pipe structure composed of the pipe 2 and the inner pipe 3 is applied. An air introduction flange 111 is attached between the sample pump 103 and the pipe P, and the air 4 compressed by the compressor 109 passes through the air introduction port 111a of the air introduction flange 111 and is a double pipe outer pipe. 2 and the inner pipe 3 flow. Furthermore, the inner tube 3 is porous, and the air 4 introduced into the outer tube 2 of the double tube flows into the inner tube 3.

  The air 4 flowing from the outer pipe 2 into the inner pipe 3 forms an air film in the vicinity of the inner wall of the inner pipe 3, thereby preventing the marine organisms and sludge from approaching the pipe wall. It is guided to the center of the fast pipe to prevent adhesion to the pipe wall.

  Normally, it is not necessary to consider the contamination of the seawater sample by air. However, in Example 1, for the sake of completeness, the water quality of the sample is changed by the air 4 introduced into the pipe, and the analysis result is affected. The position where the air 4 is introduced by the compressor 109 is installed at the rear stage of the sample collection valve 104 so as not to give the pressure.

  The diameter of the porous hole is preferably about 500 μm through which barnacle larvae, which are typical marine organisms, cannot pass. The diameter of the hole is not limited to the diameter.

  FIG. 3 is a system diagram of a sampling apparatus according to Embodiment 2 of the present invention. In the second embodiment, a compressor 109 or a gas cylinder that introduces a gas having a known component and radiation dose is installed in the outer pipe 2 of the double pipe upstream of the sample sampling valve 104 in the flow direction. By using a gas whose component and radiation dose are known, it is possible to predict the component and radiation dose of the gas mixed in the seawater 1 in the pipe, so that the gas mixed when performing the component analysis of the sample It is possible to make an evaluation by eliminating the influence of the above, and it is possible to appropriately determine the presence or absence of radioactive substances released from the system. Further, it is possible to take measures over a pipe length longer than that of the first embodiment, and it is possible to prevent adhesion of marine organisms and sludge over a wide range.

  As the gas to be used, any gas having a known component and radiation dose other than air can be used, but a gas that does not react with seawater and affect seawater components is used.

  FIG. 4 is a system diagram of a sampling apparatus according to the third embodiment. In the third embodiment, seawater 1 of the water discharge port 101 pumped up to the sample collection container 105 is used as a fluid for preventing adhesion of marine organisms and sludge. In order to introduce the seawater described above into the outer pipe 2, an outer pipe introduction sample pump 110 is installed as a seawater supply pump. The reason for using the seawater 1 at the outlet 101 as an anti-adhesion fluid for marine organisms and sludge is that the water quality of the sample changes when the anti-adhesion fluid is mixed into the sample, and the measurement of appropriate radioactivity levels is obstructed. This is to prevent it.

  FIG. 5 shows a cross-sectional view of the sampling apparatus according to the third embodiment. As described above, the marine organisms adhere to the inner wall of the pipe due to the decrease in the flow velocity or the eddy current generated near the pipe wall, and sludge accumulates. Therefore, the third embodiment is provided on the downstream side of the sample pump 110 for introducing the outer pipe. The piping having the structure shown in FIG. 5 is applied to the piping. The pipe P is a double pipe and includes an outer pipe 2 and an inner pipe 3. A seawater introduction flange 112 is attached between the sample pump 103 and the double pipe, and is connected to the sample pump 103 for introducing the inner pipe and the sample pump 110 for introducing the outer pipe. 112a is a seawater inlet. The seawater 1 pumped up by the outer pipe introduction sample pump 110 flows into the double pipe outer pipe 2 through the seawater introduction port 112a and the seawater introduction flange 112. The pressure is adjusted so that the pipe pressure of the outer pipe 2 is larger than the pipe pressure of the inner pipe 3 so that the seawater 1 in the pipe flows from the outer pipe 2 into the inner pipe 3. The seawater 1 flows from the outer pipe 2 into the inner pipe 3 to generate a flow, thereby preventing a decrease in the flow of the seawater 1 near the pipe wall of the inner pipe 3 and guiding marine organisms and sludge to the center of the pipe where the water flow is fast. Prevent access to the tube wall and prevent adhesion to the tube wall. In addition, the use of seawater 1 can prevent the accumulation of bubbles in the piping.

  FIG. 6 is a system diagram of a sampling apparatus according to Embodiment 4 of the present invention. In Example 4, a separately provided sample pump 110 for introducing an outer pipe is connected to the vicinity of the sample point 102, and all the pipes P after the sample point 102 are double pipes. The outer tube introduction sample pump 110 may be used alone.

  FIG. 7 shows a cross-sectional view of the sampling apparatus in the fourth embodiment. The pipe P is a double pipe and includes an outer pipe 2 and an inner pipe 3. Seawater 1 is pumped up by an outer pipe introduction sample pump 110 connected in the vicinity of the sample point 102, and flows into the double pipe outer pipe 2 via a seawater introduction flange 112. Reference numeral 113 denotes a diversion flange.

  In Example 3, it was not possible to take measures to prevent adhesion to the piping upstream of the sample pump 103. On the other hand, in Example 4, the sample pump 110 for introducing the outer pipe is further added in the vicinity of the water outlet 101, so that the countermeasure shown in FIG. 5 can be taken over all the pipes of the water outlet sampling apparatus. Become.

  FIG. 8 is a system diagram of a sampling apparatus according to Embodiment 5 of the present invention. In the fifth embodiment, the seawater 1 pumped up by the sample pump 103 is diverted for introducing the outer pipe 2 and for introducing the inner pipe 3, and the outer seawater is introduced through the outer pipe introduction valve 114 and the inner pipe introduction valve 115 for adjusting the flow rate, respectively. It flows into the tube 2 and the inner tube 3.

  FIG. 9 shows a cross-sectional view of the sampling apparatus in the fifth embodiment. The pipe is a double pipe and is composed of an outer pipe 2 and an inner pipe 3. As described above, the seawater 1 pumped up by the sample pump 103 is diverted through the diversion flange 113 for introducing the inner pipe 3 and for introducing the outer pipe 2. The separated seawater 1 flows into the outer pipe 2 and the inner pipe 3 through the outer pipe introduction valve 114 and the inner pipe introduction valve 115, respectively. In order to reduce the pressure of the inner pipe 3 so that the seawater 1 flows from the outer pipe 2 to the inner pipe 3, an orifice 5 is installed on the upstream side of the inner pipe 3 introduction of the double pipe.

  In Examples 3 and 4, it was necessary to prepare a plurality of sample pumps 110 for introducing the outer tube separately from the sample pump 103. On the other hand, in Example 5, the sample pump 103 is commonly used for introducing the outer tube and for introducing the inner tube, so that only one pump is required and the configuration can be simplified.

  In the sixth embodiment, an example of a sampling device in which the orientation of the porous holes is improved so that the water flow in the vicinity of the tube wall of the inner tube 3 is increased will be described.

  In the sixth embodiment, seawater 1 at the outlet 101 is used as a fluid for preventing adhesion of marine organisms and sludge.

  FIG. 10A shows a cross-sectional view of the sampling device in the sixth embodiment. FIG. 10B is a BB cross-sectional view of FIG. 10A. The central axis of the porous hole is inclined so as to flow from the upstream side of the outer tube 2 to the downstream side of the inner tube 3 with respect to the sampling flow direction. Therefore, the flow velocity of the seawater 1 in the inner pipe 3 is increased as compared with the other embodiments.

  Further, the central axis of the porous hole is such that the discharge direction from the outer tube 2 to the inner tube 3 is directed toward the vicinity of the tube wall of the inner tube 3 with respect to the pipe radial direction. Inclined. As a result, the seawater 1 flowing from the outer pipe 2 entrains the seawater 1 in the vicinity of the pipe wall of the inner pipe 3, and a swirling flow with the pipe center as an axis is generated.

  In Examples 1 to 5, the influence of the air 4 and the seawater 1 introduced into the outer pipe 2 on the flow of the seawater 1 in the inner pipe 3 is limited to the vicinity of the hole in the inner pipe 3. The effect on the tube wall is limited. On the other hand, in Example 6, since the seawater 1 of the inner pipe 3 flows downstream so as to rotate with respect to the shaft, it becomes possible to increase the flow velocity of the seawater 1 in the vicinity of the entire wall surface. The effect of preventing the adhesion of organisms and sludge can be expected. The direction of the porous hole of the inner tube 3 is not limited to the direction shown in FIGS. 10A and 10B.

  FIG. 11 is a system diagram of a sampling apparatus according to Embodiment 7 of the present invention. In the seventh embodiment, a filter 119 for removing marine organisms and sludge from seawater is installed at the outer pipe 2 inlet of the double pipe. Also, a differential pressure measuring device 120 for measuring the differential pressure between the inner tube 3 and the outer tube 2 was connected to the inlets of the inner tube 3 and the outer tube 2 to measure the differential pressure, and the differential pressure became smaller than a certain set value. In this case, a warning is issued.

  In the seventh embodiment, the filter 119 is installed at the inlet of the outer pipe 2 of the double pipe, and the adhesion of marine organisms and sludge in the outer pipe 2 can be realized.

  If the filter installed at the inlet of the outer pipe 2 is clogged, the pressure in the outer pipe 2 may drop and the seawater 1 may not flow from the outer pipe 2 to the inner pipe 3. Therefore, the pressure of the inner tube 3 and the outer tube 2 is measured by the differential pressure measuring device 120, an alarm is issued when the differential pressure becomes small, and the operator is notified of the replacement timing of the filter 119. The effect of preventing adhesion of marine organisms and sludge can be obtained.

1: Seawater 2: Outer pipe 3: Inner pipe 4: Air 5: Orifice 101: Outlet 102: Sample point 103: Sample pump 104: Sample collection valve 107: Outlet 108: Sample outlet valve 109: Compressor 110: Outer pipe Sample pump for introduction 113: Flange for diversion 114: Valve for introduction of outer pipe 115: Valve for introduction of inner pipe 116: Radiation detector 119: Filter 120: Differential pressure measuring instrument P: Piping

Claims (8)

A sample having a pipe, a sample pump and a sample collection valve, taking sample seawater from the sample point of the cooling water outlet and returning it to the cooling water outlet, and providing the sample in the middle of the pipe In the outlet sampling device of the power plant that performs seawater sampling of the outlet through the sampling valve,
The pipe is composed of a double pipe composed of an outer pipe and a porous inner pipe, and sample seawater is allowed to flow into the inner pipe and seawater collected from the outlet is introduced into the outer pipe. A water outlet sampling apparatus for a power plant, wherein the marine organisms and sludge are prevented from adhering to the inner pipe wall. The power plant outlet sampling apparatus according to claim 1 , wherein a seawater supply pump for supplying the seawater to the outer pipe is provided in the vicinity of the sample pump. The power plant outlet sampling apparatus according to claim 1 , wherein a seawater supply pump for supplying the seawater to the outer pipe is provided in the vicinity of the sample point. In the outlet sampling apparatus of the power plant according to claim 1 , a pipe is branched from the sample pump, and an outer pipe introduction valve and an inner pipe insertion valve are provided at each branch to divert seawater, A water outlet sampling apparatus for a power plant, wherein seawater is supplied to an outer pipe and the inner pipe. The water outlet sampling apparatus for a power plant according to any one of claims 1 to 4 , wherein a hole direction of the porous inner pipe is inclined in a flow direction of seawater flowing in the inner pipe with respect to the inner pipe axis direction. A water outlet sampling device for a power plant, characterized by increasing a flow velocity in the vicinity of a pipe wall of an inner pipe. 5. The water outlet sampling apparatus for a power plant according to claim 1 , wherein a hole direction of the porous inner tube is inclined with respect to the center of the inner tube in the radial direction of the inner tube. An outlet sampling apparatus for a power plant, characterized by increasing a flow velocity in the vicinity of a wall. The power plant outlet sampling apparatus according to any one of claims 1 to 6 , wherein a filter for filtering seawater is provided at the outer pipe inlet. The power plant outlet sampling apparatus according to claim 7 , wherein a differential pressure detector for detecting a pressure difference between the outer pipe and the inner pipe is provided to detect clogging of the filter. Plant outlet sampling device.

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