JP2005164269A - Device for monitoring radioactive fluid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely detect the amount of radioactivity in a hollow container, in which the hollow container is completely shielded from the outside. <P>SOLUTION: The radioactive fluid monitoring device is provided with the hollow container 21 having a fluid supply port 23 and a fluid discharge port 24; an upper lid 26 covering the upper end opening of the hollow container 21; a supply tube 23a connected to the fluid supply port 23; and a discharge tube 23a connected to the fluid discharge port 24. A radiation detector 25 is mounted in the hollow container 21. Radiation shield members 22, 26a, 23b, and 24b are provided to the outer circumference of the hollow vessel 21, the upper part of the upper lid 26, the other circumference of the supply tube 23a, and the outer circumference of the discharge tube 24a, where 1<l/t1<5 and 1<l/t2<5 are satisfied, when the thickness of the shield members 22 and 26a are t1 and t2, respectively, and the internal diameter of the hollow container 21 is l. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

Conventional technology

  In nuclear facilities such as nuclear power plants and various radiation laboratories, strict radiation management is performed to prevent radiation contamination of the environment.

  2. Description of the Related Art Conventionally, as a device for performing radiation management, a radioactive fluid monitor device that samples and measures a fluid that may be contaminated with radiation and constantly monitors the radiation concentration is used.

  As shown in FIG. 4, this radioactive fluid monitoring device has a hollow cylindrical shape that has a cubic or rectangular parallelepiped box-shaped hollow container 11 and a hollow cylinder 11 that passes through the upper lid 11 a of the hollow container 11 and is suspended in the hollow container. The radiation detector 12 is provided, and a fluid supply port 13 and a fluid discharge port 14 are provided on the side wall of the hollow container 11, respectively.

  This conventional radioactive fluid monitoring apparatus 10 is connected to a pipe line provided with a blower or a pump on the way, and allows fluid such as air or water sampled and extracted from the room or tank to pass through the hollow container 11. Radioactivity detection. In this case, the fluid passing through the hollow container 11 flows as indicated by an arrow in FIG. 4, and the radioactivity is detected by contacting the radioactivity detector 12. A part where the flow stays is generated in the part. For this reason, when the radioactive substance is contained in the fluid, this radioactive substance may stay in this part, and a radioactive concentration may become high partially. Then, the fluid containing the radioactive substance having a high concentration suddenly flows into the main flow flowing around the radiation detector 12, and the radioactivity concentration of the fluid detected by the radiation detector 12 is suddenly increased. is there.

  The present invention has been made to solve such inaccuracy of the measurement accuracy in the conventional apparatus, and accurately detects the radioactivity concentration of the fluid that is constantly flowing instantaneously, and has excellent monitoring accuracy. An object of the present invention is to provide a radioactive fluid monitoring device.

The present invention relates to an inverted conical cyclone hollow container having an open upper end, a fluid supply port provided in an upper end portion of the hollow container in a horizontal connection direction, and a fluid drain provided in a lower end central portion of the hollow container. An outlet, an upper lid covering the upper end opening of the hollow container, a supply pipe connected to the fluid supply port,
A discharge pipe connected to the fluid discharge port, a hollow cylindrical radiation detector suspended downward from the center of the upper lid in the hollow container, and a radioactive material provided at least on the outer periphery of the hollow container and on the upper lid When the inner diameter of the hollow container is l, and the thickness of the radioactive shielding member of the hollow container and the upper lid is t1, t2,
A radioactive fluid monitoring device, wherein 1 <l / t1 <5 and 1 <l / t2 <5.

  The present invention is the radioactive fluid monitoring device characterized in that a radioactive shielding member is provided on the outer periphery of the supply pipe and the discharge pipe.

  The present invention provides a radioactive fluid monitor characterized in that the thickness of the radiation shielding member of the supply pipe and the discharge pipe, the thickness of the radiation shielding member of the hollow container, and the thickness of the radiation shielding member of the upper lid are substantially the same. Device.

  According to the present invention, the fluid supplied from the fluid supply port into the hollow container flows as a swirling flow along the inner wall surface of the hollow container, and is discharged from the fluid discharge port without staying in the hollow container. At this time, the radioactive fluid flows while swirling around the outer periphery of the radiation detector, and the radiation detector can always detect the radiation dose of the fluid flowing instantaneously.

  In addition, by increasing the thickness of the radiation shielding member of the hollow container and the upper lid compared to the inner diameter of the hollow container, the inside of the hollow container can be reliably shielded from the outside, and the radiation dose in the hollow container is disturbed. It is possible to detect reliably while suppressing the influence of.

  As described above, according to the present invention, it is possible to always perform highly accurate monitoring by making the fluid flow in the hollow container a swirl flow.

  In addition, by increasing the thickness of the radiation shielding member of the hollow container and the upper lid, the inside of the hollow container can be completely shielded from the outside, and the radiation dose can be accurately detected while suppressing the influence of disturbance in the hollow container. it can.

  The present invention can be used as a monitoring device for fluid containing radiation pollutants, for example, fluid containing γ-ray pollutants.

BEST MODE FOR CARRYING OUT THE INVENTION

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

  1 and 2 are a longitudinal sectional view and a plan view showing an embodiment of a radioactive fluid monitoring apparatus according to the present invention.

  1 and 2, reference numeral 21 denotes a hollow container to which a sampling fluid is supplied. The outer periphery of the hollow container 21 is shielded by a radiation shielding member (for example, a lead member) 22 that can shield radiation. . The hollow container 21 has an inverted conical shape (funnel shape) opened at the upper end, and is smoothly curved downward, for example, hemispherical. The upper end opening of the hollow container 21 is covered with an upper lid 26.

  A fluid supply port 23 is opened in the horizontal line direction at the upper end of the hollow container 21, and a supply tube 23 a for connecting to the sampling pipe 27 (see FIG. 3) extends in the same direction to the fluid supply port 23. It is connected. In addition, a fluid discharge port 24 is formed in the center of the lower end of the hollow container 21, and a discharge tube 24 a for connecting to the sampling pipe 27 is continuously connected to the fluid discharge port 24 by bending it in a right angle direction. Has been.

  In FIGS. 1 and 2, reference numeral 25 denotes a radiation detector for detecting a radiation dose, which has an elongated hollow cylindrical shape. The radiation detector 25 penetrates the central portion of the upper lid 26 of the hollow container 21 and is suspended and fixed toward the center of the hollow container 21. It is desirable that the radiation detector 25 extends further downward from the opening position of the fluid supply port 23, and its tip extends to a position near the center of the hollow container 21.

  As shown in FIG. 1, radiation shielding members (lead members) 26a, 23b, and 24b are also provided on the upper portion of the upper lid 26, the outer periphery of the supply pipe 23a, and the outer periphery of the discharge pipe 24a, respectively.

Further, the radiation shielding members 22 and 26a of the hollow container 21 and the upper lid 26 have thicknesses t1 and t2, respectively, and when the inner diameter of the hollow container 21 is l,
1 <l / t1 <5 and 1 <l / t2 <5.

  The thicknesses of the radiation shielding members 23b and 24b of the supply pipe 23a and the discharge pipe 24a are each t3. These thicknesses t1, t2, and t3 each have substantially the same value.

  Thus, by making the thickness of the radiation shielding members 22, 26a, 23b, 24b larger than the inner diameter l of the hollow container 21, the inside of the hollow container 21 can be completely shielded from the outside. The amount of radiation can be reliably detected while suppressing the influence of disturbance in the chamber 21.

  FIG. 3 shows an example in which the radioactive fluid monitoring device 20 according to this embodiment having such a configuration is used as a monitoring device for an indoor atmosphere. To the fluid supply pipe 23a and the fluid discharge pipe 24a of the radioactive fluid monitoring device 20, there are connected sampling pipes 27 and 28, which are attached through the wall surface of the building 31, respectively. A blower 29 is provided for sampling and extracting the atmosphere. A manual valve 32 and a flow gauge 33 are disposed in the middle of the sampling pipe 27 on the supply pipe 23a side.

  Next, the operation of the present embodiment having such a configuration will be described.

  While opening the manual valve 32, the blower 29 is operated and the atmosphere (air) in the building 31 is supplied into the hollow container 21 through the sampling pipe 27. The fluid supplied from the fluid supply port 23 descends while swirling along the inner wall surface of the hollow container 21, and flows out from the fluid discharge port 24 to the sampling tube 28 (an arrow in FIG. 1 indicates this flow state). ). At this time, the fluid in the hollow container 21 flows around the outer periphery of the radiation detector 25 while turning around the radiation detector 25, and the radiation dose in the fluid is detected.

  In this case, there is no portion where the fluid stays in the hollow container 21, and a new fluid always passes continuously. Therefore, the radiation detector 25 can detect the radiation dose of the fluid in an instantaneous flow that is always sampled and flowed into the hollow container 21.

  As a result, the value detected by the radiation detector 25 accurately displays the radioactivity concentration of the fluid at this moment, and accurate monitoring can be performed.

  In the above-described embodiment, an example is shown in which the radioactivity monitoring of the atmosphere (air) in the building 31 is performed. However, the radioactivity monitoring of the fluid stored in the tank can also be performed. In this case, a pump may be used in place of the blower 29.

The longitudinal cross-sectional view which shows one Example of the radioactive fluid monitor apparatus by this invention. The top view of a radioactive fluid monitor apparatus. The systematic diagram which shows the application example of the apparatus by this invention. The schematic sectional drawing which shows the example of the conventional radioactive monitor apparatus.

Explanation of symbols

21 hollow container 22 radiation shielding member 23 fluid supply port 23a supply tube 23b radiation shielding member 24 fluid discharge port 24a discharge tube 24b radiation shielding member 25 radiation detector 26 upper lid 26a radiation shielding member

Claims (3)

An inverted conical cyclone hollow container having an open upper end, and a fluid supply port provided in the horizontal connection direction at the upper end of the hollow container,
A fluid discharge port provided at the center of the lower end of the hollow container;
An upper lid covering the upper end opening of the hollow container;
A supply pipe connected to the fluid supply port;
A discharge pipe connected to the fluid discharge port;
In the hollow container, a hollow cylindrical radiation detector suspended downward from the center of the upper lid,
A radiation shielding member provided at least on the outer periphery of the hollow container and the upper part of the upper lid, where the inner diameter of the hollow container is l, and the thicknesses of the radiation shielding members of the hollow container and the upper lid are t1 and t2, respectively.
A radioactive fluid monitoring device, wherein 1 <l / t1 <5 and 1 <l / t2 <5.   2. The radioactive fluid monitoring apparatus according to claim 1, wherein a radiation shielding member is provided on the outer periphery of the supply pipe and the discharge pipe.   3. The radioactive ray according to claim 2, wherein the thickness of the radiation shielding member of the supply tube and the discharge tube, the thickness of the radiation shielding member of the hollow container, and the thickness of the radiation shielding member of the upper lid are substantially the same. Fluid monitoring device.

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