JPS61111483A - Monitor device of radioactivity in air - Google Patents

Abstract

PURPOSE:To prevent a polluting residue with respect to a mechanism part by constituting such that the filter of a combustible cartridge type can be changed in a package. CONSTITUTION:After measurement, testing and monitor are completed, the operation of the mechanism part is slopped vinyl hoes 45 and 45', a seal band 46, a nipple 43 and a seal collar are detached from an air suction pipe 34 and a discharge tube 41. Then, with respect to a casing 2, an opening/closing cover 10 is opened through separation of a clamp 12 to take out a cartridge 28 from an attaching/detaching chamber 24, and the cartridge 28 which is held by the upper housing 29 and the lower housing 30 of the filter 42 is burnt and disposed including said two parts. Thus an operator can dispose a radio-active material without touching it thanks to detaching directly the filter 42, whereby the will not be exposed radioactivity and after-treatment can be safely carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The disclosed technology belongs to the technical field of devices that constantly detect, measure, and monitor radioactivity in the air inside and outside of facilities such as atomic couplants.

Therefore, the invention of this application collects air in a predetermined location inside and outside of a facility that handles radioactive substances such as the atomic couplant, and collects radioactive dust in a filter.
This invention relates to an airborne radioactivity monitoring device that is equipped with a detection structure inside a device casing so as to detect and measure radioactivity using a detector installed opposite to the filter, and is made portable. The casing is divided into a detection chamber equipped with a detector and an attachment/detachment chamber for attaching and detaching a cartridge with a replaceable filter. The cartridge has an opening/closing lid that can be fixed inside the cartridge, and the cartridge further includes an upper housing and a lower housing in which a filter is sandwiched between the cartridges, and an air intake pipe and an air discharge pipe are provided in both housings. This invention relates to a portable airborne radioactivity monitoring device that is equipped with a.

<Prior art> As is well known, safe operation is given top priority in facilities that handle radioactive materials, such as nuclear power plants, nuclear research institutes, and radiation medical facilities. Although strict monitoring is required for radioactive leaks at facilities, there is a need to constantly monitor the radioactive concentration in the air to prevent radioactive leaks that may occur unexpectedly in the entire facility or its surroundings. Measures are being taken.

Therefore, as a means of monitoring radioactivity in the air, the air in a predetermined area is continuously absorbed and sampled, filtered with a filter, and the dust in the air that is collected on the filter is collected. A method is used to measure its radioactivity, but
The monitoring equipment used for this purpose is equipped with detectors for alpha, beta, and gamma rays to detect and measure them, and these detection mechanisms are installed inside the casing to make it as portable as possible. .

Since alpha rays have weak permeability through substances, a scintillator coated with zinc sulfide is used to convert the radiation into light, and the light generated is detected in proportion to the intensity of the radioactivity. and measure it with a multiplier tube, while
Since β-rays and γ-rays have long ranges, they are detected and measured using a Geiger counter.

Therefore, since the air in the predetermined area to be measured is structured to flow through the filter, the detection mechanism set inside the device casing is a type of fixed device, so the First, cumulative contamination increases over time, and there is an extremely high possibility that the entire device or detection mechanism will be contaminated with radioactivity.

In particular, since the detector is installed facing the radioactive dust collected on the filter, there is a possibility that a large amount of radioactivity will adhere to it.
Essentially, it requires extreme caution.

<Problems to be Solved by the Invention> Therefore, in radioactivity monitoring equipment, it is originally preferable to install a dedicated monitoring device for each predetermined part, but it is difficult to avoid equipment costs and unforeseen situations. In order to deal with this problem, there are cases where a single monitoring device is used to sample air from different locations, so when the sampling location of the air to be measured is changed, it goes without saying that the filter must be replaced.
This has the disadvantage that the degree of radioactive contamination of the entire detection mechanism differs, and as a result, accurate measurement values cannot be obtained, and as a result, normal monitoring may not be possible.

In particular, if the entire detection mechanism becomes contaminated, the detector will naturally become contaminated as well, so the detector must be replaced, which has the disadvantage of extremely high costs. Furthermore, there is a safety issue in that there is a risk of radioactive contamination for workers during replacement.

In other words, when using a Geiger counter to detect β-rays and γ-rays, the ultra-thin mica film of 10 μm or less attached to the detection surface is easily damaged during monitoring work, and when detecting α-rays, When radioactive dust accidentally adheres to the scintillator, radioactivity immediately adheres between the zinc sulfide particles of the scintillator, which is easily decontaminated and causes photoelectron multiplication. If the pipe becomes contaminated, it must also be replaced, resulting in extremely high costs.Furthermore, workers are exposed to radiation during these operations, with filter replacement being the most radioactive. Since the concentrated material is directly taken out and replaced, there are extremely serious safety concerns.

In addition, even if the detection mechanism is not replaced, if the inside of the detection mechanism becomes contaminated, special cleaning equipment must be used to disassemble the detection mechanism and perform decontamination cleaning, and the work must be done carefully. [This process takes time and energy, and in addition, disassembly and cleaning generates radioactive waste, which poses the risk of secondary contamination, and its disposal is extremely complicated.

As mentioned above, these decontamination and disassembly operations are extremely dangerous, and in some cases, the work area expands, potentially creating a risk of secondary contamination of the surrounding air facility environment. However, as a safety measure, the detection mechanism itself is disposed of as radioactive waste without disassembling or decontaminating the detection mechanism, which has the disadvantage of significantly increasing running costs. However, there is also the disadvantage that the cost of long-term storage and management increases along with other radioactive waste.

On the other hand, during measurement monitoring, for example, when detecting β-rays and γ-rays using a Geiger counter, the ultra-thin mica film installed opposite the filter is inherently inelastic. Because it is a substance, if the amount of air flowing through the filter changes unexpectedly and suddenly, causing a pressure fluctuation, the detection surface of the mica membrane will receive expansion and contraction stress, and as mentioned above, the mica membrane will lose its elasticity. As a result, the mica membrane, which is the detection surface, is damaged due to the pressure fluctuation, and as a result, one
. , 8 phi 75. □□, a, yo. 11.-Not only will the filter be damaged, but the radioactivity concentrated on the filter due to the filter damage may promote contamination of the detection mechanism.

As mentioned above, since the mechanism inside the device is a type of fixed type, the structure is extremely complicated, especially if it is made into a compact type and portable.
There are a large number of parts and failures are likely to occur, so periodic
Irregular maintenance inspections and maintenance must be carried out frequently, resulting in poor work efficiency.Also, as mentioned above, air intake pipes and discharge pipes that must be attached to the equipment casing are difficult to handle. There is also a disadvantage that there is little freedom in assembling different parts, and operability is not good.Also, the entire device is bulky and can be seriously damaged, making it difficult to transport and making it difficult to work when changing the measurement position. There were some aspects that could not be ignored that were bad.

The purpose of the invention of this application is to solve the problems of radioactivity monitoring equipment for air around the inside and outside of facilities handling radioactive materials such as atomic couplants based on the above-mentioned prior art, and to The part that collects dust, etc. is made of a cartridge made of flammable plastic, etc., and the mechanism is designed to be replaceable and detachable from the detection mechanism inside the device.Moreover, it fully guarantees the stability of measured values and is easy to handle and operate. In addition, it prevents the spread of radioactive contamination, reduces the amount of radioactive waste generated, and extends the service life of the equipment over time.
It is an object of the present invention to provide an excellent air radioactivity monitoring device that reduces running costs and is beneficial to fields in which radioactive materials are used in various industries.

<Means/effects for solving the problem> In order to solve the above-mentioned problem, the structure of the invention of this application, which is based on the above-mentioned claims, is to solve the above-mentioned problem. The detector is divided into a detection chamber equipped with a detector in the upper part and a removable chamber for a cartridge with a replaceable filter.A detector for the copper wire is fixedly installed in the detection chamber, and a cartridge is installed in the removable chamber. It is fixed to the set site, and a removable opening/closing lid is provided, so that when monitoring and measuring the radioactivity in the air at a predetermined site, the lower housing of the upper and lower housings made of flammable plastic is used. A filter is set to collect dust in the air that has a specified radioactivity, and an upper housing covered with a transparent film such as a transparent polyester resin film or a scintillator film is hermetically fitted to the filter. Then, the upper and lower housings are integrated and set in the upper and lower housings, and an air intake pipe and an air discharge pipe that are integrally provided to the upper and lower housings are formed in advance on the opening/closing lid closing part. Set the cartridge in the guide groove, close the opening/closing lid, set the cartridge in the removable chamber with the ball plunge,
Then, a seal tube or the like is connected to the air suction and discharge pipe in a securely sealed state with one touch, and the collected air is sucked and discharged from a predetermined area, circulated to the cartridge in the monitoring device, and radiated by the filter. The radioactivity is detected and measured by a detector, and when changing the position of the collected air at the measurement site, the above hose is removed and the opening/closing lid of the casing is closed. This device takes technical measures to prevent radioactive contamination from remaining inside the monitoring device by opening the device, taking out the cartridge, and incinerating the entire cartridge without touching the filter.

<Embodiment - Configuration> Next, an embodiment of the application of this invention will be described below based on the drawings.

First, in the embodiment shown in Fig. 2.3.4, 1 is an air radioactivity monitoring device which constitutes the gist of the invention of this application, and Fig. 2.3.4 shows its external shape. The front side of the casing 2 is equipped with radioactivity measurement record paper 3, measuring instrument 4, alarm button 5.6, switch 7, etc., and the back side is equipped with connectors 8 types,
An opening/closing lid 10 which is bent at an angle of 90 degrees and can be opened and closed via a hinge 9 is provided on the back and side surfaces of the casing 2, and a hook 11 of the opening/closing lid 10 is provided on the back of the casing 2.
A clamp 12 is provided for.

Further, a lowering handle 13 is provided on the upper surface of the casing 2 to make the monitoring device 1 portable.

To explain the opening/closing lid 10 in detail, as shown in FIGS. 6 to 9, a cross-section type opening/closing i10 is pivoted to the hinge 9 provided on the internal partition wall 14 so that it can be opened and closed freely. , when the state shifts from the open state shown in FIG. 6 to the closed state shown in FIG. 7, the stopper 1 provided at one end thereof
5 is adapted to abut against the inner edge of the opening of the casing 2 for the opening/closing lid 10, and a housing member 16 formed in a semi-cylindrical shape in the vertical direction is integrally provided with the partition wall 14. Similarly, a housing member 17 having a semi-cylindrical shape in the vertical direction is formed into a housing member having a perfect circular cross section, and in this state, the hook 11 seals and fixes the closing lid to the casing 2 with the clamp 12. Furthermore, a ball plunger 18, 18, 18 is provided to fix the secondary housing to the housing member 16 provided on the opening/closing lid 10.

Further, when the casing 2 and the opening/closing lid 10 are in a sealed state as shown in FIG. 7, guide grooves 19 and 19 for an air intake pipe and a discharge pipe, which will be described later, are provided as shown in FIG. 5.

As shown in FIG. 5, inside the casing 2, a detection chamber 23 is formed by a box-shaped partition 20 and a bottom wall 22 integrally provided below the partition wall 20 with a gasket 21 interposed therebetween. The housing member 17 of the partition wall 14 and the housing member 16 of the opening/closing lid 10 are located under the bottom wall 22.
A cartridge attachment/removal chamber 24, which will be described later, is formed by the detection chamber 23.

In the detection chamber 23, as shown in FIG.
An extremely thin mica film 25 is stretched over the partition wall 20 via a mounting bracket 27.

Further, on the upper surface of the partition wall 20, there is a detector 25 as shown in the figure.
Lead wire terminals 27, 27, .
..., etc.

The detector 25 houses a photomultiplier tube for measuring α rays and a Geiger counter tube for β rays and γ rays, as in the conventional case.

On the other hand, a replaceable cartridge 28 made of a combustible material such as plastic is provided in the attachment/detachment chamber 24 and is taken out by opening and closing the opening/closing lid 10, and is set on the bottom surface inside the opening/closing lid 10. It is surrounded by a short cylindrical housing member 16.11 when the lid 10 is closed, and is pressed by a pole plunger 18.18.18 so that it can be set in a replaceable manner so that it does not wobble in the set state. There is.

As shown in FIGS. 11 to 14 in detail, the structure of the cartridge 28 includes an upper housing 29 and a lower housing 3 that are fitted relatively to each other and integrated in a sealed state.
The main body is formed into a short cylindrical shape, the upper housing member is formed into a ring shape, and a ring-shaped ventilation hole 111131 is formed inside the housing member. A film made of polyester resin, or a transparent film made of a hard and elastic material such as polystyrene or polycarbonate resin so that the filter described below can be seen through the top surface of the cartridge 28 and made of hard resin. It is attached in an airtight manner with an adhesive.

Note that the transparent film 32 may be a scintillator film.

In addition, spacers 33 are provided in spots on the inner peripheral edge of the ring-shaped ventilation groove 31 and in a cross pattern in the center, so that the transparent film is caused by negative pressure fluctuations of the collected air passing through the cartridge 28, which will be described later. 32 is drawn into the concave shape and deformed to prevent damage to the second-order delay filter.

In addition, as the design aspect of the transparent film 32, for example,
A polyester film having a specific gravity of 1.38 to 1.39 is used, and its thickness is set to 50 μm.

And, from one side of the similar ring-shaped ventilation hole 31,
A highly flammable air intake pipe 34 made of, for example, plastic is provided by press-fitting or integral molding, and a communication hole 35 for the ring-shaped ventilation groove 31 is bored at the inner end thereof. and the casing 2, and
A flange 36 is integrally formed with the slot 19 of the opening/closing lid 10 to perform a kind of sealing action by coming into contact with the slot 19 from the outside, and the outer end of the flange 36 is used as a nipple connection end for a connection boss to be described later.

Meanwhile, the lower housing 30 is a circular body having an end with a protruding cross section, and an O-ring 38, 38 is installed on the outer surface of the protrusion 37, so that when the upper housing 29 is fitted and integrated, It is designed to be sealed against the outside.

A honeycomb-shaped perforated plate 39 is formed on the upper part of the protrusion 37, and a recess 40 is formed inside to communicate with a discharge pipe 41 that is integrally molded or press-fitted. ing.

Therefore, the suction pipe 34 is communicated with the protruding pipe 41 via the ring-shaped ventilation hole 31, the perforated plate 39, and the recess 40.

A disc-shaped filter 42 coated with a scintillator is placed concentrically on the upper surface of the upper perforation plate 39 of the protrusion 37 of the lower housing 30, as in the conventional case, and the ring of the protrusion 37 The upper edge and the lower surface of the upper inner edge of the ring ventilation groove 31 of the upper housing 29 are sandwiched and set.

Therefore, as shown in FIG. 14, the collected air from the suction pipe 34 passes through the communication hole 35, passes through the ring-shaped ventilation groove 31, passes through the filter 42, enters the recess 40 from the perforated plate 39, and then enters the discharge pipe 41. It is made to stand out from the crowd.

Incidentally, the discharge pipe 41 is integrally formed with a flange 36 at a corresponding position in the same manner as the above-mentioned suction pipe 34, and its outer end is an end into which a nipple is inserted into the hose.

As shown in FIG. 15, once the outer ends of the air suction pipe 34 of the upper housing 29 and the air discharge pipe 41 of the lower housing 30 are fitted into the nipples 43, 43, they cannot be easily separated. Each nipple 4 is connected via a seal collar 44, which serves as a clamp body that
3 is connected to a pressure-resistant vinyl hose 45, 45' via a seal band 46 in a completely sealed state.

<Example - Effect> In the above configuration, at a predetermined radioactive material handling facility,
When measuring and monitoring air radioactivity in a predetermined area, it is necessary to store and set a new cartridge without radioactive contamination in the removable space 24 of the monitoring device 1.
As shown, lower housing 30 of cartridge 28
The filter 42 is placed concentrically on the perforated plate 39, and the upper housing 29, to which the transparent film 32 has been previously attached via an adhesive, is fitted concentrically, as shown in FIG. Then, the two are integrated, and the communication portion between the two is completely sealed by the O-rings 38 and 38.

Thus, the outer end 3 of the air intake pipe 34 of the upper housing 29
4 and the outer end of the air discharge tube of the lower housing 30 through a sealing collar 44.44 and a nipple 43.44.
The nipples 43 and 43 are connected to each other so that they are securely fitted inside the seal and cannot be easily removed by pulling.
A pressure-resistant vinyl hose 45 is connected to the air suction pipe 34 through a pressure-resistant vinyl hose 45', and a pressure-resistant vinyl hose 45' is connected to the air discharge pipe 45.
are connected and completely sealed with seal bands 46, 46 to complete the integral assembly of the cartridge 28.

When the assembly is completed, as shown in FIG. 14, the upper housing 29 and the lower housing 3 are connected as described above.
0 is sealed by O-rings 38 and 38, and the upper end of the protrusion 37 of the lower housing 30 and the inner lower surface of the ring-shaped ventilation groove 31 of the upper housing 29 are sandwiched by the press fitting of the upper housing 29 to the lower housing 30. The filter 42 is reliably held in a sealed state by the pressing force, and therefore passes through the ring-shaped communication groove 31 and enters the recess 4.
The leakage of the intake air passing through the ring-shaped periphery of the filter 42 is sufficiently prevented.

When the cartridge 28 that has been assembled in this way is stored and set in the removable chamber 24 in the casing 2 of the monitoring device 1, the opening/closing lid 10 is fully opened via its hinge 9, and the cartridge 28 is opened. The casing 2 and the flange 36 of the suction pipe 34 and the flange 36 of the discharge pipe 41 are seated concentrically at a predetermined position on the bottom surface of the attachment/detachment chamber 24.
Close the opening/closing lid 10 so as to securely contact and seal the guide grooves 19 and 19 of the opening/closing lid 10, and then attach the hook 11 to the opening/closing lid 10.
Then, the clamp 12 securely fixes the open/close lid 10 to the casing 20 in a sealed state.

In this case, the stopper 5 at the inner end of the opening/closing lid 10 comes into contact with the inner edge of the casing to create a completely closed state.

In the seated set state, the filter 42 is located concentrically and below the transparent film 32, and the detector 25
is positioned in a non-contact state on the lower surface of the ultra-thin mica film 26.

Furthermore, with respect to rocking and vibration caused by the handle 13 of the device 1 when being carried, rocking and vibration of the cartridge 28 within the Wa to 24 can be prevented by the housing member formed by the ball flange 18, 18 of the closed opening/closing lid 10. 16, the set state is maintained unchanged.

Therefore, in order to monitor and measure radioactive air at a predetermined location, the monitoring device 1 is carried to the location via the handle 13, or the pressure-resistant vinyl hose 45, 45 is extended. When remote measurement is performed and the discharge pipe 41 is connected to a vacuum pump (not shown) to start the operation of the entire device, the radioactive air in the area sucked from the pressure-resistant vinyl hose 45 is sucked and collected. Suction pipe 34
It passes through the casing 2 of the monitoring device 1, enters the ring-shaped ventilation groove 31 of the upper housing 29 of the cartridge 28, and further passes through the filter 42 from between the filter 42 and the transparent film 32 under the filtering action, It passes through the perforated plate 39 and is discharged from the discharge pipe 41 through the concave portion 40 .

Thus, in this process, although negative pressure acts within the cartridge 28, the fitting joint between the lower housing 30 and the upper housing 31 is completely sealed by the O-rings 38, 38, so that the inside of the removable chamber 24 is completely sealed. There is no possibility of air entering or leaking due to negative pressure fluctuations, and therefore there is no risk of radioactive contamination of the attachment/detachment chamber 24 or the detection chamber 23.

Further, even if the pressure between the filter 42 and the transparent film 32 decreases due to negative pressure fluctuations, there is no risk of the transparent film 32 coming into contact with the filter 42 even if the transparent film 32 is dented due to the interposition of the spacers 33, 33, . . . .

Also, by installing the spacers 33 and 33, the transparent film 3
The ring-shaped peripheral edge of the cartridge 28 can be sufficiently maintained in adhesive contact with the inner edge of the upper end of the ring-shaped ventilation groove 31 of the upper housing 29, so that the radioactivity testing function of the cartridge 28 is reliably maintained. Ru.

The radiation of the radioactive air or dust collected on the upper surface of the filter 42 is detected by the upper detector 25, as shown in FIG. 16.17.

Therefore, to explain the radiation detection function, regarding the detection of α rays 47 shown in FIG. 16, the filter 42
As is well known, alpha rays 47 from radioactive dust collected on the upper surface of the filter 42 by the air flow 48 have a property of being difficult to pass through substances. It will not reach the detector 25.

However, in the invention of this application, by applying a scintillator to the back surface of the transparent film, that is, the surface facing the filter 42, the α rays are converted into light 49 on the scintillator-coated surface, and therefore, no light is emitted. The number of times the light 49 is emitted is photoelectronized through the transparent film 32, and detected and measured using a multiplier tube.

Therefore, it acts to confine radioactive nuclides on the upper surface of the filter 42.

-Measurement and detection of β-rays and γ-rays is carried out by the detector 25 or the counter tube, as shown in Fig. 17.
As is well known, β rays and γ rays have high material penetration energy and have a long range, so the transparent film 32
Its existence does not impede its passage in any way.

That is, as shown in FIG. 18, when the horizontal axis is the thickness μ and the vertical axis is the attenuation rate (%), the attenuation of β-rays and γ-rays by nuclide depending on the thickness of the transparent film 32 is shown. For example, in the case of uranium, which is used relatively often in facilities that use radioactive materials, attenuation absorption of about 8% occurs with a thickness of 50μ, but strontium 90 In the case of , there is a 10% attenuation absorption.

However, in any case, if counting errors of the radiation detector are taken into consideration, there is virtually no problem with monitoring.

Further, if necessary, it is possible to design the absorption damping valve to be mechanically corrected by the mechanism of the monitoring device as an attenuation coefficient, thereby making it possible to obtain more accurate measured values.

Therefore, the radiation emitted from the filter 42 passes through the transparent film 32 without being attenuated and is measured by the Geiger counter.

Incidentally, when the specific gravity of the transparent film 32 is large and thick, attenuation occurs, and therefore, as described above, the transparent film 32
It is preferable to use a material that has a low specific gravity and is as thin as possible.

In this way, when the radioactivity monitoring and measurement in the air at the relevant site is completed, the next desired site is monitored and measured.
As mentioned above, in that case, by replacing the cartridge 28 and resetting the cartridge 28 with a new filter 42, not only installation and removal 24 but also prevention of remaining radioactive contamination in the detection chamber 23 and safety. To ensure that countermeasures are taken and to obtain stable and accurate measurement data.

Therefore, once the measurement and inspection monitoring of the relevant part is completed,
The operation of the nuclide mechanism was stopped and the vinyl hose 45.45
', seal band 46, nipple 43, seal collar 4
4, the opening/closing lid 10 is opened from the casing 2 by disassociating the clamp 12, and the cartridge 28 is taken out from inside the attachment/detachment 24 and held between the upper housing 29 and the lower housing 30 of the filter 42. By incinerating the entire cartridge 28, the cartridge 28 can be disposed of without coming into contact with radioactive materials by directly removing the filter 42, etc. Therefore, workers are not exposed to radiation and safe post-processing is possible.

Also, as a result, there is no residual radioactive contamination inside the monitoring device 1, and next, a new filter 4 with no radioactive contamination is installed.
By installing the cartridge 28 in which the cartridge 28 is set, no radiation exposure occurs when the cartridge 28 is installed next time, and the data to be detected and measured is not influenced by the radioactive contamination residual data, allowing correct measurement and monitoring.

Furthermore, since the amount of secondary waste generated by incineration is small, it is easy to manage it for a long time, and safety management can be carried out satisfactorily.

Furthermore, it is of course possible to carry out more precise measurements using predetermined mechanical means.

Note that by making the cartridge 28 more compact in design, the size of the monitoring device 1 can be made more compact, and it can also be weighed.

It should be noted that the embodiment of the application of this invention is, of course, not limited to the above-mentioned embodiment. For example, a type of gate is integrally provided in the suction pipe and the discharge pipe to trap residual air and dispose of it. It is possible to adopt a number of methods, such as doing so.

<Effects of the Invention> As described above, according to the invention of this application, in a radioactivity monitoring device in a facility handling radioactive materials, the radioactive contamination of each mechanism in the device can be replaced by a combustible cartridge-type filter package. As a result, it is possible to prevent contamination from remaining in the mechanism, the detection unit can be made compact, and the monitoring device itself can be made into an integrated portable type, making it easy to handle and improving measurement accuracy. This has the excellent effect of making it more accurate.

As a result, it is possible to eliminate measurement errors in the detection mechanism such as filters that have been used once due to contamination within the detection unit, and this has the excellent effect of improving data reliability.

In addition, since the filter storage housing part is a cartridge type, there is no need to directly touch the filter when replacing the filter, there is no possibility of accidentally dropping the filter and contaminating the floor, etc., and there is no need to perform decontamination work. This also has the effect of preventing the spread of contamination in the work area.

Therefore, radioactive contamination of the bodies of those engaged in the work is prevented, and the excellent effect of eliminating the risk of exposure to radiation in terms of safety measures is achieved.

In addition, the decontamination equipment for radioactive contamination or the labor saving can be achieved, which improves efficiency and reduces costs.

By incorporating the detection section into the main body of the monitoring device, the device can be made smaller and more portable, and the excellent effect of making it easier to handle can also be achieved.

Additionally, since the filter can be freely replaced between the upper and lower housings of the cartridge, a new filter can be installed with a single touch, making handling smooth and efficient. This excellent effect is achieved, and furthermore, since the filter can be incinerated together with the cartridge every time a predetermined portion is measured and inspected, the advantage of the cartridge mechanism can be fully realized.

In addition, since the air suction pipe and the air discharge pipe can be connected to the cartridge, the air suction pipe and the air discharge pipe can be connected to the cartridge by opening the opening/closing lid 111 to the casing of the monitoring device. The effect is that it can be automatically attached, easily taken out and disposed of.

In addition, by providing a ball plunge or the like for the cartridge in the opening/closing lid, the opening/closing lid is designed to have the effect that the cartridge can be positioned in a predetermined position and easily set in the attachment/detachment chamber when the opening/closing lid is closed.

By doing so, there is also the effect that the cartridge can be set in the casing of the monitoring device in a completely sealed state.

In this way, it is possible to prevent internal contamination of the detection unit, and it can be disposed of in a completely sealed state, reducing labor costs and significantly reducing the amount of non-flammable radioactive waste that requires long-term storage. However, it is also possible to reduce storage costs.

In addition, since it uses a cartridge system, it is easy to set and reset, and by simplifying the 811 part, it reduces the number of failures after detection during use, enables accurate use, and significantly reduces running costs. The effect of being able to do so is also Qin.

[Brief explanation of the drawing]

The drawing is an explanatory diagram of one embodiment of the invention of this application, and the drawing is a first embodiment of the invention of this application.
The figure is a partially cutaway overall perspective view, Figure 2 is an overall side view, Figure 3 is an overall front view, Figure 4 is an overall rear view, Figure 5 is a partial vertical sectional view of the casing, and Figure 6 is an open/closed view. Figure 7 is a plan view of the lid in the open state, Figure 7 is a plan view of the lid in the closed state, Figure 8 is a rear view of the lid with the lid open after the housing has been set, Figure 9 is a rear view of the lid in the closed state, and Figure 10 is the cartridge installed state. partial longitudinal section,
Fig. 11 is a longitudinal sectional view of the cartridge, Fig. 12 is a rear view of the same, Fig. 13 is a plan view of the same, Fig. 14 is a partially enlarged sectional view of Fig. 11, Fig. 15 is a cartridge assembly diagram, and Fig. 16 is an α 17 is a perspective view of detecting β-rays and γ-rays, and FIG. 18 is a graph showing the relationship between the thickness of the transparent film and the radiation attenuation rate. 47.47'... Radiation, 42... Filter, 25... Detector, 2... Casing, 1.
...Radiation monitoring device, 23...Detector, 28...
・Cartridge, 24...152 yen opening/closing lid,
38...Seal, 34...Air suction pipe, 41...
...Air discharge pipe applicant Power Reactor and Nuclear Fuel Development Corporation Figure 3 Figure 4 Figure 5 Figure 8 Figure 9 Figure 10 Figure 12 Figure 11 Figure 13 Where did Hiruichi receive the money?

Claims (2)

[Claims] (1) In an air radioactivity monitoring device equipped with a detector installed in a casing opposite to a filter that collects radioactive dust in the air, the inside of the casing includes a detection chamber equipped with the detector and the filter. 1. A monitoring device for radioactivity in the air, characterized in that the casing is provided with an opening/closing lid for the cartridge, and the casing is provided with an opening/closing lid for the cartridge. (2) In a device for monitoring radioactivity in the air, in which the casing is equipped with a detector installed opposite to a filter that collects dust in the air that has radioactivity, detection in which the inside of the casing is equipped with the above-mentioned detector. The cartridge has an upper housing and a lower housing separated by a seal that holds the filter in a replaceable manner, and both housings are connected to an air intake pipe. and an air discharge pipe.