JP3056572B2 - Radon daughter nuclide concentration measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radon daughter nuclide concentration measuring device for calculating the concentration of all radon daughter nuclides from the total and free radon daughter nuclide components.

[0002]

2. Description of the Related Art Conventionally, sample air is collected by a paper filter, and Radon daughter nuclides RaA ( ²¹⁸ Po) and RaC '( ²¹⁴ Po) collected on paper by an α-ray height analyzer are used two to three times. By measuring twice, all components (R
A device is known which calculates each concentration (Bg / m ³ ) of aA, RaB, and RaC, the equilibrium equivalent radon concentration (Bg / m ³ ), and the potential α energy concentration (J / m ³ ).
Here, RaB is ²¹⁴ Pb and RaC is ²¹⁴ Bi.

In addition, sample air is collected by a mesh filter, and each concentration (Bg / m ³ ) of a free component of a radon daughter nuclide collected on a mesh by an α-ray height analyzer and an equilibrium equivalent radon concentration (Bg) / M ³ ) and a device for calculating the potential α energy concentration (J / m ³ ) are known.

[0004] Radon daughter nuclides, especially RaA ( ²¹⁸⁾
At the moment when Po) is generated, it is in a simple atomic state (a state not attached to the aerosol), and then adheres to the aerosol existing in the air to form a radioactive aerosol.
In order to accurately measure such radon daughter nuclides that are liable to adhere, it is necessary to keep the piping to the paper or mesh to be collected as short as possible and free from obstructions. There has been proposed a radon daughter nuclide concentration measuring device which can be moved to a sampling place independently of a main body.

[0005] FIG. 3 is a schematic diagram showing a collection and detection unit for simultaneous dust collection and simultaneous measurement. A suction port 12 is provided on the side surface of the housing 10, and α-rays are detected in the suction port 12. The detector 14 is arranged with the detection surface facing backward with respect to the suction port. Then, a filter 16 made of paper or mesh for collecting dust is located near the detection surface of the α-ray detector 14,
The filter 16 includes a supply reel 18 and a take-up reel 20.
And is step-feeded by a predetermined amount for each detection. The rear side of the filter 16 is connected to a suction pump (not shown), and the radon daughter nuclide is collected on the filter 16 by sucking the sample air by the suction force of the suction pump.

However, in the trapping detection section of such a radon daughter nuclide concentration measuring device, the α-ray detector 14
Is arranged, so that the radon daughter nuclide easily adheres to the α-ray detector 14 unnecessarily.

Therefore, as a solution to this drawback,
As shown in FIG. 4, a collection detector of a radon daughter nuclide concentration measuring apparatus in which an α-ray detector 14 is arranged in a housing 10 and near a suction port 12 and a detection surface is oriented in a direction perpendicular to a suction direction. Has been proposed.

In this trapping detection section, when the sample air is trapped, the trapping portion of the filter 16 is changed to the α-ray detector 14.
Move to a position close to the detection surface of. Then, α-rays from the collection portion of the filter 16 are detected by the α-ray detector 14.

[0009]

Since the trapping detection section of the conventional radon daughter nuclide concentration measuring apparatus shown in FIGS. 3 and 4 is constructed as described above, the suction port 12 must have at least α-ray detection. Since the length of the vessel 14 is required, there is a problem that the radon daughter nuclide easily adheres to the inner wall of the suction port 12. Further, in order to detect all components and free components of the radon daughter nuclide, it is necessary to detect free components after all components have been detected, which is troublesome.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to prevent the radon daughter nuclide from adhering to portions other than the filter as much as possible and to simultaneously remove all components and free components of the radon daughter nuclide. An object of the present invention is to provide a radon daughter nuclide concentration measuring device that can be detected.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a radon daughter nuclide concentration measuring apparatus according to the present invention automatically sends all the components of a radon daughter nuclide by sequentially feeding a roll of paper. A roll paper collection detection unit that collects, a roll mesh collection detection unit that sequentially sends a rolled mesh to automatically collect free components of radon daughter nuclides in a single atom state, and a roll paper collection detection unit A calculation unit for calculating at least the concentrations of all the radon daughter nuclides and the free components from the radon daughter nuclides and the free components of the radon daughter nuclides detected by the roll mesh collection detection unit.

Further, the roll paper collection detection section and the roll mesh collection detection section each have α near the suction port.
A line detector is provided, and the detection surface of the α-ray detector is arranged so as to be substantially parallel to the suction direction.

[0013]

The radon daughter nuclide concentration measuring apparatus according to the present invention, based on the above configuration, sequentially sends rolled paper and automatically collects all the components of the radon daughter nuclide by a roll paper collection detecting unit, and simultaneously proceeds with this. Then, the roll-shaped mesh is sequentially sent to automatically collect the free components of the radon daughter nuclides that are not attached to the aerosol by the roll mesh collection detection unit, and all the components of the radon daughter nuclide detected by the roll paper collection detection unit. From the free component of the radon daughter nuclide detected by the roll mesh collection detection unit, the calculation unit calculates the concentration of all the components and the free component of the radon daughter nuclide.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1 and FIG. 2, the radon daughter nuclide concentration measuring device includes a roll paper collection detecting section 22 (see FIG. 1) for automatically collecting all components of the radon daughter nuclide, and an aerosol or the like. Roll mesh collection detection unit 24 that automatically collects free components of radon daughter nuclide that has not been used (see FIG. 1)
And the concentration of all components of the radon daughter nuclide from the free component of the radon daughter nuclide detected by the roll paper collection detection unit 24 and the concentration of all components of the radon daughter nuclide detected by the roll mesh collection detection unit 24, the equilibrium equivalent radon concentration, etc. (Main body) 26 (see FIG. 2) for calculating
And a control unit 31 capable of performing a trapping detection operation by step-feeding the roll-shaped paper or the mesh by a predetermined amount for each detection in accordance with the signal from the controller.

In FIG. 1, a roll paper collection detecting section 2
A suction port 12 is provided on a side surface of the second housing 10. Further, an α-ray detector 14 is disposed near the suction port 12 and at the left corner in the housing 10 so that the detection surface is substantially parallel to the suction direction. Is connected to a preamplifier 28 for amplifying the
8 is connected to the calculation unit 26 via the buffer 30.

A paper 32 for collecting dust is located near the detection surface of the α-ray detector 14.
Wound on the supply reel 18 and the take-up reel 20,
Each time it is detected, it is stepped by a predetermined amount. In addition, on the back side of the paper 32, a pipe 36 that communicates with a suction pump 34 described later is provided.
The sample air is sucked from the suction port 12 by the suction force of No. 4 to collect radon daughter nuclides on the paper 32.

Further, a suction port 12 is provided on a side surface of the casing 10 of the roll mesh collection detecting section 24. Further, in the vicinity of the suction port 12 and at the left corner in the housing 10,
Α-ray detector 1 so that the detection surface is substantially parallel to the suction direction
4, a preamplifier 28 for amplifying a detection signal is connected to the α-ray detector 14, and the preamplifier 28
Are connected to the calculation unit 26 via the buffer 30.

A mesh 38 for collecting dust is located near the detection surface of the α-ray detector 14.
Is wound around a supply reel 18 and a take-up reel 20, and is fed stepwise by a predetermined amount for each detection. A pipe 36 communicating with a suction pump 34 described later is provided on the back side of the mesh 38, and the sample air is sucked from the suction port 12 by the suction force of the suction pump 34, and the radon daughter nuclide is free on the mesh 38. Collect components.

Here, in the control section 31, according to a signal from the MPU 54 of the main body operation section 26, the roll-shaped paper or the mesh is step-forwarded by a predetermined amount for each detection so that the collection detection operation can be performed. Has become.

In FIG. 2, the calculation unit 26 includes a roll paper measurement suction unit 40 for performing measurement suction of the roll paper collection detection unit 22, a roll mesh measurement suction unit 42 for performing measurement suction of the roll mesh collection detection unit 24, and A personal computer 44 and the like are provided.

The roll paper measurement suction unit 40
The amplifier 46 amplifies the signal from the buffer 30 of the roll paper collection detection unit 22. The amplifier 46 includes an A / D
Converter 48 is connected. Further, a memory 50 is connected to the A / D converter 48,
0, a microprocessor unit (MPU) 54, a communication circuit 56, a ROM 58, an R
AM 60 and I / O 62 are connected, and I / O 62
Is connected to a display 64.

The pipe 3 communicating with the suction pump 34
In the path of No. 6, a mass flow meter 66 for detecting a flow rate is provided.
And a digital pressure gauge 68, and a VF converter 70 is connected to the mass flow meter 66. A scaler 72 is connected to the VF converter 70, and the scaler 72 is connected to the bus line 52. Further, the digital pressure gauge 68 and the suction pump 34 are connected to the bus line 52 via the I / O port 74.

The roll mesh measuring and suctioning section 42 has the same configuration, and the same reference numerals are given and the description is omitted.

The personal computer 44 is connected to the communication circuit 56 of the roll paper measurement suction unit 40 and the roll mesh measurement suction unit 42, and the printer 76 and the hard disk 78 are connected to the personal computer 44. . Next, the operation of the present embodiment will be described.

When measuring the concentration of the radon daughter nuclide, the roll paper collection detection unit 22 and the roll mesh collection detection unit 2
4 is placed away from the main body computing section 26 at the sampling location,
The suction pump 34 is activated to start collection. After a lapse of a predetermined time, the supply reel 18 and the take-up reel 20 are rotated to move the collection portion of the paper 32 to a position close to the detection surface of the α-ray detector 14 and to collect the mesh 38. The part is moved to a position close to the detection surface of the α-ray detector 14. Further, all components of the radon daughter nuclide are detected by the α-ray detector 14 of the roll paper collection / detection unit 22, and the single atom state not attached to the aerosol or the like is detected by the α-ray detector 14 of the roll mesh collection / detection unit 24. Of free radon daughter nuclides.

Then, the detection signals of all the components of the radon daughter nuclide detected by the α-ray detector 14 of the roll paper collection / detection section 22 are amplified by the preamplifier 28, and are supplied via the buffer 30 to the roll paper measurement suction section 40. Amplifier 4
Sent to 6. Further, the detection signal is amplified by the amplifier 46, converted into a digital signal by the A / D converter 48, and stored in the memory 50. And the memory 50
Is sent to the personal computer 44 by the communication circuit 56.

Similarly, the detection signal of the free component of the radon daughter nuclide which is not attached to the aerosol and the like detected by the α-ray detector 14 of the roll mesh collection detecting section 24 is amplified by the preamplifier 28 and the buffer 30 It is sent to the amplifier 46 of the roll mesh measurement suction unit 42 through the. Further, the detection signal is amplified by an amplifier 46, converted into a digital signal by an A / D converter 48, and
0 is stored. Then, the digital signal stored in the memory 50 is sent to the personal computer 44 by the communication circuit 56.

Then, the personal computer 44
From the detection signals of all the components of the radon daughter nuclide and the detection signals of the free components of the radon daughter nuclide not attached to the aerosol, etc., the respective concentrations (Bg / m ³ ) of all the components of the radon daughter nuclide (RaA, RaB, RaC) , Equilibrium equivalent radon concentration (Bg /
m ³ ), the potential α energy concentration (J / m ³ ), and the concentration of the free component of the radon daughter nuclide (Bg / m ³ ),
The equilibrium equivalent radon concentration (Bg / m ³ ) and the potential α energy concentration (J / m ³ ) are calculated, the calculation result is printed out by the printer 76, and the calculation result is stored in the hard disk 78.

[0030]

As described above, according to the present invention,
The roll paper collection and detection unit automatically collects all the components of the radon daughter nuclide, and the roll mesh collection and detection unit automatically collects the free component of the radon daughter nuclide that is not attached to the aerosol, etc. From the components and free components, the calculation unit calculates the concentrations of all components and free components of the radon daughter nuclide,
Since it is configured to calculate the equilibrium equivalent radon concentration,
It is possible to simultaneously detect all the components and the free components of the radon daughter nuclide, and to save the trouble of separately detecting all the components and the free components. In addition, the roll paper collection detection unit and the roll mesh collection detection unit each have an α near the suction port.
A line detector is provided, and the detection surface of the α-ray detector is arranged so as to be substantially parallel to the suction direction.Therefore, the distance from the suction port to the roll paper or roll mesh is shortened, and radon is applied to the inner wall of the suction port. Adhesion of daughter nuclides can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a trapping detection unit of a radon daughter nuclide concentration measuring device according to the present invention.

FIG. 2 is a block diagram showing a configuration of a calculation unit of the radon daughter nuclide concentration measuring apparatus according to the present invention.

FIG. 3 is a schematic configuration diagram showing a conventional collection detection unit.

FIG. 4 is a schematic configuration diagram showing a conventional collection detection unit.

[Explanation of symbols]

 Reference Signs List 12 suction port 14 α-ray detector 22 roll paper collection detection unit 24 roll mesh collection detection unit 26 calculation unit (main body) 40 roll paper measurement suction unit 42 roll mesh measurement suction unit

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takatoshi Hattori 2-1-1-1, Iwatokita, Komae-shi, Tokyo Safety Research Laboratory, Nuclear Power Department, Komae Research Institute, Central Research Institute of Electric Power Industry (72) Inventor, Yoshito Ota Tokyo 6-22-1, Mure, Mitaka-shi, Tokyo Aloka Co., Ltd. (72) Inventor Takeshi Takeshi 6-22-1, Mure, Mitaka-shi, Tokyo Inspector Shinichi Nagai, Aloka Co., Ltd. (56) References JP 61-221690 (JP, A) JP-A-56-119878 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01T 1/167 G01T 7/04

Claims (2)

(57) [Claims] 1. A roll paper collection detector for sequentially feeding roll-shaped paper and automatically collecting all components of radon daughter nuclides, and a roll mesh for sequentially sending free components of radon daughter nuclides in a single atom state. A roll mesh collection detector that automatically collects, and at least all of the radon daughter nuclides from all components of the radon daughter nuclides detected by the roll paper collection detector and free components of the radon daughter nuclides detected by the roll mesh collection detector A calculation unit for calculating the concentrations of the component and the free component, wherein the radon daughter nuclide concentration measuring device is provided. 2. The roll paper collection detection section and the roll mesh collection detection section each include an α-ray detector near a suction port, and a detection surface of the α-ray detector is substantially parallel to a suction direction. The radon daughter nuclide concentration measuring device according to claim 1, wherein the device is arranged.