JP6524758B2 - Water monitor - Google Patents

Description

  The present invention relates to a water monitor capable of measuring radiation in measured water.

  Conventionally, in a radiation handling facility handling radioactive materials and radiation such as a nuclear power plant, radiation is measured using coolant water and drainage as water to be measured from the viewpoint of soundness and safety. As a device for performing this measurement, for example, a water monitor disclosed in Patent Document 1 is known. The water monitor of patent document 1 provides a radiation detector in the container into which the water of measurement object is introduce | transduced, and is comprised. The container consists of a tank and a lid, and on the inner surface of the container is formed an inner layer of a gel coat layer. The surface of the inner layer is a smooth and smooth surface to prevent the radioactive substance from adhering to the inside of the container.

Japanese Patent Application Publication No. 2004-170184

  However, even in Patent Document 1, depending on the substance having radioactivity, it may adhere to the inner layer of the container. For this reason, there is a problem that substances having radioactivity remain in the inner layer around the radiation detector and raise the radiation background. Moreover, in order to wash the substance having the radioactivity attached to the inside of the container, it is necessary to remove the lid from the tank, which increases the labor and time burden of the operation.

  The present invention has been made in view of such a point, and it is an object of the present invention to provide a water monitor which can easily remove a substance having radioactivity attached in a channel and can reduce radiation background. I assume.

The water monitor of the present invention comprises a flow path forming a space for introducing the water to be measured flowing in a radiation handling facility, a radiation detection device for detecting radiation in the water under measurement in the space, and the flow path a storage portion for storing provided the radiation detecting device, and a cleaning device for cleaning by discharging washing water area of the accommodating portion to be measured water contact, the cleaning apparatus, said flow passage an intervening portion which is interposed between the housing portion, and wherein Rukoto which downstream end is connected to the intermediate portion having a and wash water supply path for supplying the wash water into the space.

According to this configuration, the storage unit for containing the radiation detection device is cleaned by the washing water, so that the substance having radioactivity is prevented from remaining attached to the area in the vicinity of the radiation detection device which the measured water contacts. can do. As a result, the radiation background can be reduced, and the reliability of radiation measurement can be improved. In addition, by discharging washing water with the washing apparatus, it is possible to remove substances having radioactivity, and it is possible to carry out washing easily and quickly without the work of disassembling the flow path and the container. . In addition, washing water can be discharged using an intervening portion interposed between the flow path and the storage portion, and the washing water is discharged from the vicinity of the attachment position of the storage portion to the flow path, and the storage portion is washed with washing water. It can be washed away.

  The cleaning apparatus may spray cleaning water having a discharge pressure higher than a predetermined level directly to the storage unit. In this configuration, the radioactive substance attached to the container can be removed to be washed away.

  The housing portion may have a substantially cylindrical peripheral wall, and the intervening portion may be disposed in the housing portion with a gap. In this configuration, the washing water can be discharged from the position where the gap is interposed in the housing portion.

  A groove extending along the circumferential direction may be formed on the inner peripheral surface side of the intervening portion. In this configuration, it is possible to flow the washing water into the groove and to discharge the washing water from the entire groove. Thus, the washing water can be discharged from the entire circumferential direction of the housing portion, and the wide range of the housing portion can be washed away with the washing water.

  The flow path includes a main pipe extending in a straight line direction, and a projecting pipe connected to the main pipe and projecting in a direction intersecting with the main pipe, and the accommodating portion is interposed at the tip of the projecting pipe and the accommodating portion Should be attached. In this configuration, the projecting tube can be a reinforcing rib.

  In the flow path, a boundary area between the main pipe and the projecting pipe may be formed by a curved surface. In this configuration, the detection range of the radiation by the radiation detection device can be expanded as compared to the case where the region has a projected corner shape in the space of the flow passage, because the region has a curved surface.

  A drain for discharging the washing water may be connected to the flow path. In this configuration, the wash water from which the radioactive substance has been washed away can be drained from the drain of a system different from the flow path.

  According to the present invention, the substance having radioactivity attached in the flow path can be easily removed, and the radiation background can be reduced.

It is an example of the schematic block diagram of the radiation handling facility where the water monitor concerning this embodiment is applied. It is a top view of the above-mentioned water monitor. It is a front view of the said water monitor which abbreviate | omitted the partial structure. It is an AA line arrow directional cross-sectional view of FIG. It is a plane sectional view of FIG. It is a longitudinal cross-sectional view for description around a washing | cleaning apparatus and an accommodating part.

  Hereinafter, the present embodiment will be described in detail with reference to the attached drawings. In the following description, “left” and “right” are based on FIG. 2 and “upper” and “lower” are based on FIG. 3 unless otherwise specified. Moreover, "front" uses the lower part of FIG. 2, and "rear" uses the upper part of FIG. 2 as a reference.

  FIG. 1A and FIG. 1B are an example of the schematic block diagram about a part of radiation handling facility where the water monitor concerning this embodiment is applied. The radiation handling facility 100 of FIG. 1A is a part of a nuclear power plant, and the steam generated by the steam generator 101 flows into the turbine 102 to do work, and then flows into the condenser 103. The condensed water from the condenser 103 is degassed by the deaerator 104, heated by the feed water heater 105, and then returned to the steam generator 101. Further, high temperature blow-down water is discharged from the steam generator 101 and flows into the filter 107 to remove impurities, and then demineralized by the electrodeionization apparatus 108 and returned to the condenser 103.

  In the radiation handling facility 100 of FIG. 1A, the water monitor according to the present embodiment detects radiation using water flowing through the inlet or outlet of the electric demineralizer 108 as the water to be measured.

  The radiation handling facility 110 of FIG. 1B is a reactor auxiliary machine cooling water facility in a nuclear power plant, and includes a nuclear reactor auxiliary machine cooling water cooler 111. Sea water is introduced into the reactor auxiliary cooling water cooler 111 via the sea water pump 112, and after heat exchange, it is returned to the sea from the water outlet 113. Further, the cooling water from the reactor auxiliary cooling water surge tank 115 flows into the reactor auxiliary cooling water cooler 111 via the pump 116, and the cooling water is cooled by the seawater and returned.

  In the radiation handling facility 110 of FIG. 1B, the water monitor according to the present embodiment detects radiation using the coolant flowing through the inlet or the outlet of the reactor accessory cooling water cooler 111 as the water to be measured.

  The water monitor according to the present embodiment is not limited to the facilities described above, and can be used in various radiation handling facilities. For example, it can be suitably used even when it is installed in a liquid waste processing system of a radiation handling facility and cooling water in each facility constituting the liquid waste processing system is used as the water to be measured. . Further, the above is just an example, and the water monitor according to the present embodiment can be used in various radiation handling facilities.

  Subsequently, a water monitor according to the present embodiment will be described. FIG. 2 is a plan view of the water monitor according to the present embodiment, FIG. 3 is a front view of the water monitor with a partial configuration omitted, and FIG. 4 is a view taken along line AA of FIG. FIG. As shown in FIG. 2, the water monitor 10 includes a pipe 11 (flow path) extending in the left-right direction. As also shown in FIG. 3 and FIG. 4, a space S into which the water to be measured such as the drainage in the radiation handling facility described above is introduced is formed inside the pipe 11. The pipe 11 forms a part of a drainage system (not shown), one of the left and right ends is an introduction part of the water to be measured, and the other end is a discharge part of the water to be measured. Valves (not shown) are respectively provided on the upstream side of the introduction part and on the downstream side of the discharge part, so that the supply and stop of the water to be measured to the space S can be switched.

  The pipe 11 includes a main pipe 13 extending in a straight line direction to the left and right, and a projecting pipe 14 connected to the front side of the main pipe 13 and projecting forward in a direction intersecting the main pipe 13. The main pipe 13 includes an intermediate portion 13a in which the projecting pipes 14 are connected, and extension portions 13b connected to the left and right ends of the intermediate portion 13a by welding or the like. The flanges 15 are respectively welded to the ends of the extensions 13 b opposite to the intermediate portion 13 a, and pipes (not shown) constituting a drainage system are connected via the flanges 15. In the pipe 11, a boundary area between the main pipe 13 and the projecting pipe 14 is formed by a curved surface which is a quarter arc shape in a cross sectional view of FIG.

  The water monitor 10 further includes a cleaning device 20, a housing portion 21, and a radiation detection device 22 (in FIG. 3 and FIG. 4, the housing portion 21 and the radiation detection device 22 are not shown).

  The cleaning apparatus 20 includes a cleaning water supply passage 24 connected to a cleaning water supply source (not shown), and an intervening portion 25 in communication with the downstream end of the cleaning water supply passage 24. A connector 27 is provided on the downstream end side of the cleaning water supply passage 24 on the side of the pipe 11. The connector 27 is connected to a passage 33 (see FIG. 6) formed above the intervening portion 25 described later. A valve 28 is provided on the upstream end side of the cleaning water supply passage 24, and by operating this valve 28, switching between supply and stop of cleaning water can be made. The washing water is not particularly limited, but pure water is used in the present embodiment.

  The intermediate portion 25 is formed in an annular shape and is fixed to the front end (tip end) of the projecting tube 14 by welding or the like. As shown in FIG. 3, a plurality of screw holes 25 a are formed at predetermined intervals in the circumferential direction on the front surface of the intervening portion 25. In addition, a reception groove 25b circular in a front view is formed on the front surface of the intervening portion 25. The reception groove 25b is formed to open the front, and can receive an O-ring 30 (see FIG. 6) inside. Provided.

  FIG. 5 is a plan sectional view of FIG. 2, and FIG. 6 is an explanatory longitudinal sectional view around the cleaning device and the housing portion. As shown in FIGS. 5 and 6, a groove 32 extending in the circumferential direction is formed on the inner peripheral surface of the intervening portion 25. The groove 32 opens the inner peripheral surface side of the intervening portion 25, and a passage 33 (not shown in FIG. 5) is formed at one position of the bottom. The passage 33 extends in the radial direction of the intervening portion 25, and one end side communicates with the bottom of the groove 32, and the other end side is connected to the connector 27. Therefore, the downstream end of the washing water supply passage 24 communicates with the inner circumferential surface side of the intervening portion 25, and the washing water supplied from the washing water supply passage 24 passes through the passage 33 and the space inside the protruding pipe 14 from the groove 32. It is discharged to S. The discharge pressure source of the washing water is a pump or the like, and the discharge pressure is preferably 150 kPa or more.

  As shown in FIGS. 2 to 4, the cleaning device 20 further includes a drain 35 connected to one of the extensions 13 b of the pipe 11. The drain 35 discharges the cleaning water in the space S of the pipe 11 to the outside of the pipe 11. A valve 36 (not shown in FIG. 4) is provided on the upstream end side of the drain 35, and by operating this valve 36, it becomes possible to switch between discharging and stopping the washing water.

  As shown in FIG. 2 and FIG. 5, the housing portion 21 is attached in a state in which the intervening portion 25 is interposed at the tip of the projecting tube 14 in the pipe 11, and accommodates the radiation detection device 22. The housing portion 21 includes an annular attached portion 38 installed in front of the intervening portion 25 and a bottomed container-like protective portion 39 fixed to the inner peripheral surface side of the attached portion 38 by welding or the like. There is. In the mounting portion 38, a through hole (not shown) is formed at a position corresponding to the screw hole 25a (see FIG. 3), and a bolt 41 (not shown in FIG. 5) is screwed into the screw hole 25a through the through hole. The attachment portion 38 is attached to the intervening portion 25 through the interposition. At this time, the O-ring 30 (see FIG. 6) is sandwiched by the relative surfaces of the mounting portion 38 and the interposing portion 25 to ensure watertightness therebetween.

  The protection unit 39 is made of stainless steel or the like, and has a function of protecting the radiation detection device 22 accommodated therein from drainage. The protective portion 39 has a substantially cylindrical peripheral wall 39a located on the inside of the mounting portion 38 at the front end side and extending in the projecting direction (longitudinal direction) of the projecting tube 14 and a rear end side of the peripheral wall 39a And a bottom wall 39b. The rear end and the bottom wall 39 b of the peripheral wall 39 a are disposed rearward of the front end of the main pipe 13, and are immersed in and drained in the drainage water flowing through the main pipe 13. Further, the outer surface of the peripheral wall 39a and the inner peripheral surface of the interposing portion 25 are disposed with a slight gap therebetween.

  The radiation detection device 22 is not particularly limited, but a radiation detector such as a NaI scintillation detector is used, and the measurement target is mainly γ-rays. The radiation detection device 22 includes a cylindrical container 22a housed in the protection unit 39, and a scintillator 22b made of NaI (Tl) is disposed in the lower part of the container 22a. The scintillator 22b fluoresces upon incidence of radiation, and the light is converted into a detection signal through a photomultiplier or the like, and is input to a predetermined control device through a cable 22d connected through a connector 22c.

  In the above configuration, when the substance in the water to be measured flowing in the space S has radioactivity, radiation is emitted from the substance. This radiation is incident on the scintillator 22 b, and the radiation detection device 22 detects the radiation. At this time, when a part of the pipe 11 is located between the radioactive substance and the scintillator 22b, the radiation is linearly emitted, so the radiation incident on the scintillator 22b is attenuated and the sensitivity is lowered. In the present embodiment, since the boundary area between the main pipe 13 and the projecting pipe 14 is formed by a curved surface, the range in which radiation is detected by the scintillator 22b is expanded compared to the case where the boundary area is formed by two orthogonal surfaces. be able to. The detection range of the scintillator 22b can be expanded by increasing the depth of the protection portion 39 and bringing the position of the scintillator 22b closer to the central axis position of the main pipe 13, but the area where the protection portion 39 contacts the water to be measured is It is not preferable because it becomes large and the pressure loss of the water to be measured. As in the present embodiment, by making the boundary region between the main pipe 13 and the projecting pipe 14 a curved surface, the pressure loss of the water to be measured can be suppressed and the monitoring range of radioactive substances in the water to be measured can be kept wide. .

  Next, a cleaning method by the cleaning device 20 according to the present embodiment will be described with reference to FIG. The cleaning by the cleaning device 20 cleans the entire space S of the piping 11 (see FIG. 2), but particularly cleans the outer surface of the protective portion 39 of the storage unit 21 with which the water to be measured contacts with the cleaning water. In this cleaning, first, valves (not shown) upstream and downstream of the pipe 11 are operated to discharge all the water to be measured in the space S. Next, the flush water valve 28 (see FIG. 2) is operated to feed flush water to the intervening portion 25 through the flush water supply passage 24. Then, the washing water is discharged from the inner periphery of the intervening part 25, and the washing water is sprayed directly on the outer surface of the protection part 39 of the storage part 21. At the same time, washing water flows along the grooves 32 of the interposing part 25. That is, on the front end side of the circumferential wall 39a, the washing water flows so as to annularly surround the circumferential wall 39a in a front view. And washing water which flowed in the inside of slot 32 flows back and down from slot 32 by self-weight and water pressure of washing water. At this time, the washing water comes along the entire circumferential direction of the peripheral wall 39a and the outer surface of the bottom 39b (see FIG. 5), so that foreign substances and the like attached to the outer surface can be washed away. In addition, since the water pressure of wash water can be ensured by setting discharge pressure to 150 kPa or more, the more favorable washing effect can be acquired.

  The cleaning water that has cleaned the storage portion 21 also flushes the inner circumferential surface of the pipe 11 that forms the space S, and is discharged to the outside of the pipe 11 from the drain 35 (see FIG. 2).

  As described above, according to the present embodiment, the outer surface of the protective portion 39 of the housing portion 21 can be washed with washing water, and the radioactive substance is prevented from adhering to and remaining in the protective portion 39. be able to. As a result, the radiation background can be reduced in detection of radiation, and the reliability of radiation measurement can be improved. In addition, since the outer surface of the protection portion 39 is cleaned as described above, the radioactive substance can be removed only by supplying the washing water from the outside of the pipe 11 through the washing water supply passage 24. Therefore, the operation of disassembling and reassembling each component of the water monitor 10 for cleaning can be eliminated, and the burden of operation for cleaning can be reduced.

  Further, since the cleaning water supply passage 24 is connected to the intervening portion 25 for attaching the storage portion 21, the parts connecting only the cleaning water supply passage 24 can be omitted, and the number of parts can be reduced. In addition, washing water can be sprayed from the entire annularly extending groove 32 to efficiently wash out the entire circumferential direction of the peripheral wall 39a in a wide range.

  Moreover, since the protrusion pipe | tube 14 is formed in the piping 11 and the intervening part 25 was welded to this protrusion pipe | tube 14, the protrusion pipe | tube 14 becomes reinforcement. Furthermore, the projecting pipe 14 can suppress deformation of the pipe 11 due to heat at the time of welding.

  The present invention is not limited to the above embodiment, and can be implemented with various modifications. Further, the numerical values, dimensions, materials, and directions described in the above embodiment are not particularly limited. In addition, it is possible to change suitably, unless it deviates from the range of the object of the present invention.

  For example, the supply position of the wash water from the wash water supply passage 24 to the space S may be an arbitrary position of the main pipe 13 or the projecting pipe 14 instead of the intervening portion 25, And may be discharged into the space S.

  Moreover, although the case where the flow path was made into the piping 11 was demonstrated in the said embodiment, it is not restricted to this, It is good also as a chamber etc. which store a to-be-measured water.

  Further, the groove 32 of the intervening portion 25 may be formed in a spirally extending shape, or the cleaning water may be sprayed from the communication position with the cleaning water supply passage 24 without forming the groove 32 in the intervening portion 25. . However, forming the groove 32 in the intervening portion 25 is advantageous in that washing water can easily flow over the entire outer periphery of the protective portion 39 as described above.

10 Water monitor 11 Piping (flow path)
13 main pipe 14 projecting pipe 20 cleaning device 21 housing part 22 radiation detection device 24 cleaning water supply path 25 intervening part 32 groove 35 drain 39a peripheral wall 100 radiation handling facility 110 radiation handling facility S space

Claims (7)

A flow path forming a space for introducing the water to be measured flowing in the radiation handling facility;
A radiation detection device for detecting radiation in the water under measurement in the space;
An accommodating portion provided in the flow path and accommodating the radiation detection device;
A cleaning device for discharging the cleaning water to clean the area of the storage unit in contact with the measured water;
Equipped with
The cleaning apparatus has an intervening portion interposed between the flow path and the storage portion, and a cleaning water supply path whose downstream end is connected to the intervening portion and which supplies cleaning water into the space. Water monitor characterized by   The water monitor according to claim 1, wherein the cleaning device sprays cleaning water having a discharge pressure higher than a predetermined level directly to the storage unit. The housing portion has a substantially cylindrical peripheral wall,
The water monitor according to claim 1 or 2 , wherein the intervening portion is disposed in the housing portion with a gap. The water monitor according to claim 3 , wherein a groove extending along the circumferential direction is formed on the inner peripheral surface side of the intervening portion. The flow path includes: a main pipe extending in a straight direction; and a projecting pipe connected to the main pipe and projecting in a direction intersecting the main pipe.
Water monitor according to any one of claims 1 to 4, characterized in that the receiving portion by interposing the intermediate portion to the tip of the projecting tube is attached. The water monitor according to claim 5 , wherein a boundary area between the main pipe and the projecting pipe is formed by a curved surface. The water monitor according to any one of claims 1 to 6 , wherein a drain for discharging the washing water is connected to the flow path.

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