JP4551831B2 - Radioactive dust monitor and method of using filter paper in radioactive dust monitor - Google Patents

Description

  In order to monitor the concentration of radioactive material in the air at a nuclear power plant or the like, the present invention collects dust in the air by sucking the air at the monitoring point through the filter paper for measuring the radioactive material. A radioactive dust monitor that measures the concentration (radioactive concentration) of radioactive material present in the air at the monitoring point by detecting radiation from dust collected in a radiation detector, and a method of using filter paper in the radioactive dust monitor About.

  FIG. 6 is a plan view showing an internal configuration of a conventional radioactive dust monitor. The radioactive dust monitor 10 includes a filter paper supply spool 14 and a filter paper take-up spool 15 for winding a long filter paper 13 for measuring a radioactive substance in an airtight box 12 disposed in a main body 11, and a guide. The rollers 16 and 17, the suction head 18, the filter paper drive roller 19, the tension pulley 20, the belt 21, the filter paper breakage detection photoelectric switch 22, the suction port 23, and the radiation detector 24 are configured. Yes.

The filter paper 13 is a filter paper specified by JIS Z 4601 (radioactive dust sampler), and generally has a total length of 90 m. The filter paper supply spool 14, the guide roller 16, the filter paper breakage detection switch 22, the suction head 18, and the filter paper drive roller 19. The guide roller 17 and the filter paper take-up spool 15 are set in this order.
The filter paper 13 set in this way is conveyed in the direction indicated by the arrow Y1 continuously or intermittently by a filter paper driving roller 19 driven by being coupled to a motor (not shown). The filter paper supply spool 14 is always braked, and the filter paper take-up spool 15 is connected to the filter paper drive roller 19 by a belt 21 via a tension pulley 20 so that it does not loosen at a predetermined speed. To be transported.

Between the guide roller 16 disposed on the filter paper supply spool 14 side and the filter paper drive roller 19 disposed on the filter paper take-up spool 15 side, the suction head 18, the radiation detector 24, Are arranged opposite to each other. The suction head 18 is in contact with the filter paper 13, and a gap for supplying air to the filter paper 13 is provided between the radiation detector 24 and the filter paper 13.
Further, as shown in FIG. 7, the dust is collected in a square shape having the same shape as the suction head suction port 18 a by the suction by the suction head 18, so that the dust collection region 13 a is formed on the surface of the filter paper 13. It has become.

  Dimensions such as one side of the dust collection area 13a and the interval between adjacent dust collection areas 13a are set to suitable values for each dust monitor. As an example, in the conventional apparatus, one side of the dust collection region 13a has a size of 52.5 mm, and a space of 22.5 mm is opened between the dust collection region 13a and the dust collection region 13a. ing. This interval is such that the radiation remaining in the previous dust collection area 13a is opened so as not to interfere with the dust collection in the current dust collection area 13a, and the filter paper 13 is conveyed at a pitch of 75 mm by the filter paper drive roller 19. Opened by being done.

The suction port 23 is an opening of a pipe connected to a monitoring point such as a radioactive substance handling room via a suction pump (not shown), and air at the monitoring point is sucked by the suction pump and is airtight box from the suction port 23 12 is led.
A suction pump (not shown) for sucking air is connected to the suction head 18 by piping, and dust in the air guided into the airtight box 12 by suction by the suction pump is collected on the filter paper 13. Be dusted. By detecting the radiation from the collected dust by the radiation detector 24, the radioactivity concentration existing in the air at the monitoring point is measured.

  More specifically, when the radioactivity concentration is measured, a portion of the filter paper 13 that is not used for collecting dust is first disposed between the radiation detector 24 and the suction head 18. Thereafter, suction is performed from the suction head 18 for a specified time, and after this suction, the filter paper 13 is transported by 75 mm by transport control by the filter paper drive roller 19. That is, it is transported so that the front side of the current dust collection region 13a comes to a position 22.5 mm away from the rear side of the previous dust collection region 13a, and between the radiation detector 24 and the suction head 18. Placed in. After this arrangement, suction is performed for a specified time, and the operation in which the filter paper 13 is conveyed by 75 mm is repeated, whereby the radioactivity concentration is measured.

In addition, each part dimension, a numerical value, etc. in the above-mentioned description describe all examples.
As this type of conventional apparatus, for example, there are those described in Patent Documents 1 and 2.
JP 2003-315461 A JP 2002-162320 A

  By the way, in the conventional radioactive dust monitor, the filter paper 13 having a total length of 90 m is used to collect the dust, but between the square dust collection region 13a having a side of 52.5 mm and the dust collection region 13a. In order to prevent the radiation remaining in the previous dust collection area 13a from interfering with the dust collection in the current dust collection area 13a, an interval of 22.5 mm is provided. From this, the usage rate of the filter paper 13 is about 70% (52.5 mm ÷ 75 mm = 0.7), and it is discarded while leaving about 30% of the uncollected area.

However, the filter paper 13 is very expensive, and such a filter paper 13 is disposed of while leaving an uncollected area of about 30%, so that the running cost for measuring the radioactivity concentration becomes very high. There is a problem.
The present invention has been made in view of such a problem, and can be used to reduce the running cost for measuring the radioactivity concentration by using a filter paper for measuring a radioactive substance without waste with high use efficiency, Furthermore, the present invention provides a radioactive dust monitor capable of performing the same measurement as when a new filter paper is used without changing the conventional measurement conditions by using an undusted portion of the filter paper, and a method of using the filter paper in the radioactive dust monitor. The purpose is that.

In order to achieve the above object, a radioactive dust monitor according to claim 1 of the present invention sucks air at a monitoring point of a radioactive material handling facility into an airtight space, and sucks the sucked air into the first and second windings. taken to provisions time sucked by the suction means through the elongated filter paper to be conveyed is wound on one among the unit, the radiation detecting means of radiation from the dust which is dust collection on the filter paper by suction In the radioactive dust monitor to detect in the above, the plate is arranged and fixed facing the surface of the filter paper, and has two parallel sides perpendicular to the straight line in the conveying direction of the filter paper, and the width of the two sides is Marker means that is at least the same size as the width in the transport direction in the dust collection area of the filter paper, and a length that is at least the same as twice the width in the transport direction in the dust collection area as one pitch length, This Comprising conveying means for conveying the filter paper by one pitch length, and said first and filter paper rewinding machine to rewind the wound filter paper in one of the second winding means, the said filter paper by the transport means At the time of setting the filter paper at the time of winding on either one of the first and second winding means, marking is performed according to one side of the marker means, and then the pitch is conveyed by one pitch length by the conveying means. While being sucked by the suction means and the radiation detection by the radiation detection means in the dust collection area, it is wound around one of the first and second winding means, and is then rewound by the filter paper unwinding machine. The marking of the filter paper is aligned with the other side of the marker means, and then conveyed by the pitch means by the conveying means, and the suction by the suction means and the radiation in the reuse area between the dust collection areas It is characterized by leaving performing radiation detection by means.

  According to this configuration, first, after the filter paper is set on the first and second winding means, a line is marked on the filter paper while the pen is in contact with one of the two sides of the marker means. Thereafter, when the radioactive dust monitor is activated, suction is performed by the suction means for a predetermined time, and after this suction, the filter paper is transported by one pitch length by the transport means. By repeating this suction and conveyance, the dust collection area is formed on the filter paper at the same interval as the width of the dust collection area. Then, when the filter paper is rewound after being used to the end, the line marked on the filter paper is set on the first and second winding means so as to be aligned with the other side of the marker means. The suction port of the means is arranged in an unused area between the already used dust collection area and the dust collection area. After that, when the radioactive dust monitor is activated, the filter paper is transported by one pitch length after the suction by the transport means. Therefore, the suction port of the suction means can be adjusted to the unused area every time the transport is performed. it can. Thus, since an unused area | region can be formed between the dust collection area | regions of a filter paper and a dust collection area | region, and this unused area | region can be used, a filter paper can be used efficiently without waste.

The radioactive dust monitor according to claim 2 of the present invention is the radioactive dust monitor according to claim 1, wherein the width of the two sides of the marker means is added to the width in the transport direction in the dust collection area of the dust of the filter paper. The one pitch length is set to a length obtained by adding a filter paper transport error to twice the width in the transport direction.
According to this configuration, when the first filter paper is used, an unused area having a length obtained by adding a filter paper conveyance error to the width of the dust collection area is formed between the dust collection area and the dust collection area of the filter paper. . By forming an unused area with a width that takes into account the filter paper transport error in this way, even if there is a transport error, the suction port of the suction means surely enters the unused area when transporting the filter paper during reuse. Filter paper can be conveyed.

According to a third aspect of the present invention, there is provided a radioactive dust monitor that sucks air at a monitoring point of a radioactive material handling facility into an airtight space and passes the sucked air between the first and second winding means. or the other wound provisions sucked constant time by the suction means through the elongated filter paper that is conveyed to, radioactive dust monitor the radiation from the dust which is dust collection on the filter paper by suction detected by radiation detection means In the filter paper, the length of at least the same length as twice the width in the transport direction in the dust collection area of the filter paper is defined as one pitch length, and the filter paper is transported by one pitch length to convey the first and second windings. A conveying means for rewinding the paper after being wound by either one of the take-up means, and being disposed and fixed facing the surface of the filter paper, and the first and second take-up of the filter paper by the conveying means Any one of the means When the filter paper set at the time of wound on, and the marker means for marking the surface of the filter paper, and detecting means for detecting the mark attached to the filter paper, the filter paper the first and second in the conveying means After winding on one of the winding means, at the time of rewinding , the mark position is obtained based on the mark information detected by the detecting means to stop the rewinding of the filter paper, and from this mark position Control means for controlling the conveying means so as to convey the filter paper at least as long as the width in the conveying direction in the dust collecting area and to oppose the reuse area between the dust collecting areas to the suction means ; It is characterized by having prepared.
According to this configuration, it is possible to automatically perform the marking on the filter paper performed by a person in claim 1 and the alignment at the time of reuse.

The radioactive dust monitor according to claim 4 of the present invention is the radioactive dust monitor according to claim 3, wherein the one pitch length is set to a length obtained by adding a filter paper transport error to a length twice the width in the transport direction. The length of the controlled filter paper from the mark position is a length obtained by adding a filter paper transport error to the width in the transport direction in the dust collection region .

  According to this configuration, when the filter paper is set at the time of reuse, the filter paper can be conveyed and set so that the suction port of the suction means surely enters the unused area even if there is a conveyance error. The filter paper can be transported so that the suction port of the suction means surely enters the unused area even during transport by the transport means after the setting even if there is a transport error.

According to a fifth aspect of the present invention, there is provided a method for using a filter paper in a radioactive dust monitor, wherein air at a monitoring point of a radioactive material handling facility is sucked into an airtight space, and the sucked air is first and second winding means. The suction means sucks it for a specified time through a long filter paper that is wound around one of the two and conveyed and the radiation detection means detects the radiation from the dust collected on the filter paper. In the method of using the filter paper in the radioactive dust monitor, a first step of marking the filter paper when setting the filter paper when the filter paper is wound around one of the first and second winding means by the conveying means. And when the filter paper is transported after being suctioned by the suction means after being marked in the first step, the width in the transport direction in the dust collection area of the filter paper. A length at least the same as the double length is defined as one pitch length, and the first pitch length is used to convey the filter paper. When the filter paper is rewound and used up to the end, the first pitch is used. The filter paper is transported by a length at least equal to the width of the dust collection area in the transport direction from the position of the mark given in the step, and the reuse area between the dust collection areas is opposed to the suction means. And a third step.

  According to this method, first, when the filter paper is set in the first and second winding means, a person marks the filter paper. Thereafter, by the activation of the radioactive dust monitor, the suction by the suction means and the transport of one pitch length by the transport means are alternately repeated. By repeating this, a dust collection area is formed on the filter paper at the same interval as the width of the dust collection area. When the filter paper is rewound after being used to the end, the measurer transports the filter paper from the mark position of the filter paper by a length at least equal to the width in the transport direction in the dust collection area. By setting, the suction port of the suction means is set to be disposed in an unused area between the already used dust collection area and the dust collection area. Since the filter paper is transported by one pitch length in the same manner as described above at the time of subsequent activation, it is possible to perform suction by matching the suction port of the suction means with the unused area each time transport is performed. Thus, since an unused area | region can be formed between the dust collection area | regions of a filter paper and a dust collection area | region, and this unused area | region can be used, a filter paper can be used efficiently without waste.

  As described above, according to the present invention, it is possible to reduce the running cost for measuring the radioactivity concentration by using the filter paper for measuring radioactive substances without waste with high use efficiency. There is an effect that the same measurement as that used can be performed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, parts corresponding to each other in all the drawings in this specification are denoted by the same reference numerals, and description of the overlapping parts will be omitted as appropriate.
FIG. 1 shows a configuration of a radioactive dust monitor according to an embodiment of the present invention, (a) is a plan view showing an internal configuration of the radioactive dust monitor, and (b) shows a marker fitting disposed on the radioactive dust monitor. It is the figure seen from the bottom in the paper surface.

The radioactive dust monitor 30 shown in FIG. 1 is different from the conventional radioactive dust monitor 10 shown in FIG. 6 in that a plate-shaped marker fitting 32 facing the surface of the filter paper 13 with a gap is arranged in the hermetic box 12. It is that the conveyance pitch of the filter paper 13 by the conveyance control of the filter paper drive roller 19 is set to (52.5 × 2 + α) mm as shown in FIG.
The transport pitch is 52.5 mm which is the same as the width of the dust collection area 13a of the filter paper 13, and an interval of 52.5 mm + α which is a length obtained by adding the filter paper transport error α when the filter paper 13 is transported is the dust collection area 13a. And a pitch for opening between the dust collection region 13a.

By sending the filter paper 13 at this transport pitch, a reuse area 13b having a width of 52.5 mm + α for collecting dust again is formed between the dust collection area 13a and the dust collection area 13a.
In the reuse area 13b, the filter paper 13 is used once after being completely used. At this time, the reuse area 13b is adjacent to the dust collection area 13a used first, but can be used without any problem for the following reason.

Since the radiation adhering to the dust collection region 13a is greatly attenuated in a short period, when the used filter paper 13 is rewound and reused, until the dust collection in the reuse region 13b is finished and the measurement of radiation is started, This is because the previous radiation adhering to the dust collection area 13a is attenuated to a level that does not interfere with the reuse area 13b.
More specifically, the marker fitting 32 is a quadrangular plate having two parallel sides orthogonal to the straight line in the conveyance direction of the filter paper 13 so that the conveyance of the filter paper 13 is not hindered between the surface of the filter paper 13. It is arranged to face the surface via a gap for fixing, and is fixed in the airtight box 12 with screws or the like.

Further, the width of two parallel sides of the marker fitting 32 is 52.5 mm + α. Hereinafter, of the two parallel sides, the side on the filter paper supply spool 14 side is referred to as the front side, and the side on the filter paper take-up spool 15 side is referred to as the rear side. In addition, the material of the marker metal fitting 32 should just be a hard material, such as a metal material and a plastic material, and any color, such as transparent and coloring, may be sufficient.
Further, the marker fitting 32 is used for drawing the marking line 32a on the filter paper 13 while the pen is in contact with the front side when the filter paper 13 is set to the spools 14 and 15 for the first time. Further, when the second setting is performed after the filter paper 13 has been used and rewound, the marking line 32a is set to coincide with the rear side of the marker fitting 32 as shown in FIG. Used.

However, although the marking line 32a is used here as an example of marking, any mark, character, small hole, or the like may be used as long as the mark can be recognized and positioned by a person.
By setting the filter paper 13 as described above, the suction head suction port 18a is disposed at a position that coincides with the reuse area 13b, and the filter paper 13 is subsequently transported at the transport pitch described above. The suction head suction port 18a is arranged at a position that coincides with the reuse area 13b each time the sheet is conveyed.

Next, the measurement process of the radioactive concentration by the radioactive dust monitor 30 of such a structure is demonstrated. However, it is assumed that the filter paper transport error α is 5 mm. As a result, the conveyance pitch becomes (52.5 × 2 + 5) = 110 mm.
First, the filter paper 13 wound around the filter paper supply spool 14 by the measurer passes through the guide roller 16, the filter paper breakage detection photoelectric switch 22, the suction head 18, the marker fitting 32, the filter paper drive roller 19, and the guide roller 17. It is wound and set on the filter paper winding spool 15.
After this setting, the measurer draws the marking line 32 a on the filter paper 13 while bringing the pen into contact with the front side of the marker fitting 32.

  Thereafter, when the radioactive dust monitor 30 is activated and measurement of the radioactive concentration is started, suction is performed by the suction head 18 for a specified time. After this suction, the filter paper 13 is transported at a transport pitch of 110 mm by the transport control of the filter paper drive roller 19. Only transported. When suction and conveyance are repeated in this way, and the filter paper 13 is used up to the end of the filter paper take-up spool 15 and wound up, the measurer is substantially the same as the initial setting state of the filter paper 13 on the filter paper supply spool 14. Perform the rewinding operation. This operation is necessary because the filter paper 13 taken up on the take-up spool 15 side of the radioactive dust monitor 30 incorporating the conventional transport mechanism cannot be reused as it is due to unevenness of the end face. The filter paper 13 is rewound using a filter paper rewinder. At this time, if one filter paper unwinding machine is prepared and used in common with a plurality of radioactive dust monitors 30 owned, it can be realized at a lower cost than when a rewinding function is added to each dust monitor. it can.

After this operation, the measurer sets the marking line 32a of the filter paper 13 so as to coincide with the rear side of the marker fitting 32. Thus, the suction head suction port 18a is arranged at a position that coincides with the reuse area 13b.
Thereafter, when the measurer activates the radioactive dust monitor 30, the filter paper 13 is transported by 110 mm of the transport pitch at the time of transport. Therefore, each time the reusable area 13b is arranged at a position coincident with the suction head suction port 18a. Suctioned by the suction head 18.

  As described above, according to the radioactive dust monitor 30 of the present embodiment, when the filter paper 13 is set, the marking line 32 a is marked on the filter paper 13 while the pen is in contact with the front side of the marker fitting 32. Thereafter, when the radioactive dust monitor 30 is activated, suction is performed by the suction head 18 for a specified time, and after this suction, the filter paper 13 is transported for the length of the transport pitch. By repeating this suction and conveyance, the dust collection area 13a is formed on the filter paper 13 with the same interval as the width of the dust collection area 13a.

  Then, when the filter paper 13 is used after being used up to the end, when the marking line 32a marked on the filter paper 13 is set in accordance with the rear side of the marker fitting 32, the suction head suction port 18a is already It arrange | positions in the reuse area | region 13b which is an unused area | region between the used dust collection area | region 13a and the dust collection area | region 13a. Thereafter, when the radioactive dust monitor 30 is activated, the filter paper 13 is transported by the length of the transport pitch after suction. Therefore, the suction of the suction head suction port 18a to the reuse area 13b can be performed each time transport is performed. it can.

Thus, since the reuse area 13b can be formed between the dust collection area 13a and the dust collection area 13a of the filter paper 13, and this reuse area 13b can be used, the filter paper 13 can be used efficiently without waste. Can do.
In the case of this embodiment, when the filter paper 13 is reused, the usage rate of the filter paper 13 is (52.5 mm of the dust collection area 13a + 52.5 mm of the reuse area 13b) / 110 mm of the conveyance pitch length = 0. From the calculation of 955, it is about 95.5%. That is, the usage rate is significantly improved from about 70% of the conventional usage rate.

In addition, like the radioactive dust monitor 40 shown in FIG. 4, the marker part 42, the mark detection part 43, and the filter paper reuse control part 44 are provided, and a measurer performs using the marker metal fitting 32 demonstrated above. A process equivalent to the reuse of the filter paper 13 may be automatically performed.
The marker portion 42 is disposed and fixed opposite to the surface of the filter paper 13 through a gap for preventing the conveyance of the filter paper 13 from being hindered. In addition, the marker unit 42 marks the filter paper 13 by the marking control of the filter paper reuse control unit 44 when the filter paper 13 is set to the spools 14 and 15 for the first time. This marking is to mark the filter paper 13 by inkjet, laser, punching or the like.

The mark detection unit 43 is realized by using an imaging unit such as a camera. The mark detection unit 43 detects the mark by imaging the mark attached to the filter paper 13 by the mark detection control of the filter paper reuse control unit 44, and detects the mark. The information is output to the filter paper reuse control unit 44.
The filter paper reuse control unit 44 performs marking control when the filter paper 13 is set to the spools 14 and 15 for the first time. After the filter paper 13 is completely used, the mark detection unit 43 detects the mark by the mark detection control. Let By this detection, the mark position is obtained by using the mark detection information input from the mark detection unit 43, and the filter paper 13 is conveyed in the direction of the filter paper take-up spool 15 by the length of 52.5 mm + α from the mark position. Take control. This control is performed by controlling a stepping motor that is a power source of the filter paper drive roller 19. By the conveyance control, the suction head suction port 18 a is arranged at a position that coincides with the reuse area 13 b of the filter paper 13.

Thereafter, as described in the above embodiment, the filter paper 13 is transported at a transport pitch of (52.5 × 2 + α) mm. Therefore, each time the transport is performed at the transport pitch, the suction head suction port 18a is It is arranged at a position that coincides with the reuse area 13b.
If the filter paper reuse control is performed in this manner, the marking by the measurer and the alignment at the time of reuse are eliminated, and accordingly, the man-hour for measuring the radioactivity concentration can be reduced.

Further, like the radioactive dust monitor 50 shown in FIG. 5, a mechanism for rewinding the filter paper is added to the radioactive dust monitor 40, and a series of processing accompanying the reuse of the filter paper 13 performed by the measurer is automatically performed. You may make it perform.
In this embodiment, a forward conveying motor 26 is coupled to the rotating shaft of the filter paper drive roller 19 via a first clutch 25, and the filter paper is coupled to the rotating shaft of the filter paper supply spool 14 via a second clutch 27. A rewinding motor 28 is coupled.

  The filter paper reuse control unit 45 performs the marking control when the filter paper 13 is set to the spools 14 and 15 for the first time, and when all the filter paper 13 is used in the first measurement, the filter clutch driving roller is driven by the first clutch 25. The rotary shaft 19 and the motor 26 are disconnected, and the transport mechanism is controlled so that the rotary shaft of the filter paper supply spool 14 and the motor 28 are coupled by the second clutch 27 to rewind the filter paper 13.

  Further, when the filter paper 13 is rewound, the filter paper reuse control unit 45 causes the mark detection unit 43 to detect the mark by the mark detection control as in the above-described embodiment, and when the mark position is obtained, Rewinding is stopped, the rotary shaft of the filter paper supply spool 14 and the motor 28 are disconnected by the first and second clutches 25 and 27, and the rotary shaft of the filter paper driving roller 19 and the motor 26 are coupled to convey the filter paper 13. Switch the direction to the same direction as when measuring. Then, the filter paper 13 is conveyed in the direction of the filter paper take-up spool 15 by the length of 52.5 mm + α described above from the mark position. The control of the filter paper feed amount for alignment is performed, for example, by measuring the feed amount using a slit disk provided on the rotary shaft of the filter paper drive roller 19 and a photoelectric sensor for detecting the rotation. Also good. By this conveyance control, the suction head suction port 18 a is arranged at a position that coincides with the reuse area 13 b of the filter paper 13.

Thereafter, as described in the above embodiment, the filter paper 13 is transported at a transport pitch of (52.5 × 2 + α) mm. Therefore, each time the transport is performed at the transport pitch, the suction head suction port 18a is It is arranged at a position that coincides with the reuse area 13b.
In this way, marking by the measurer, rewinding of the filter paper, and alignment at the time of reuse are eliminated, and the man-hour for measuring the radioactivity concentration can be further reduced.

In addition, the measurer may draw the marking line 32a due to an object difference without providing the marker metal fitting 32 in the radioactive dust monitor 30 of the above embodiment.
In this case, when the filter paper 13 is set, the measurer draws the marking line 32a due to an object difference. After that, as in the above embodiment, the radioactive concentration is measured by repeating the suction by the suction head 18 and the conveyance by the filter paper drive roller 19 at the conveyance pitch length = (52.5 × 2 + α) mm. Then, when the filter paper 13 is used after being used up to the end, it is moved (conveyed) from the position of the marking line 32a by the length of 52.5 mm + α of the dust collection region 13a and set.
Also by such a method, the filter paper 13 can be used efficiently without waste as in the above embodiment.

The structure of the radioactive dust monitor which concerns on the 1st Embodiment of this invention is shown, (a) is a top view which shows the structure inside a radioactive dust monitor, (b) is the paper surface of the marker metal fitting arrange | positioned at the radioactive dust monitor. FIG. It is a figure which shows the width | variety of the conveyance direction of the dust collection area | region and reuse area | region of these filter paper used for the radioactive dust monitor which concerns on the said embodiment, and these area | regions. It is a figure for demonstrating the position alignment at the time of reuse of a filter paper in the radioactive dust monitor which concerns on the said embodiment. It is a top view which shows the internal structure at the time of automating the filter paper reuse of the radioactive dust monitor which concerns on the 2nd Embodiment of this invention. It is a top view which shows the internal structure at the time of automating the filter paper reuse of the radioactive dust monitor which concerns on the 3rd Embodiment of this invention. It is a top view which shows the structure inside the conventional radioactive dust monitor. It is a figure which shows the width | variety of the conveyance direction between the dust collection area | region of each filter paper used for the conventional radioactive dust monitor, and each dust collection area | region.

Explanation of symbols

10, 30, 40, 50 Radioactive dust monitor 11 Main body 12 Airtight box 13 Filter paper 13a Dust collection area 13b Reuse area 14 Filter paper supply spool 15 Filter paper take-up spool 16, 17 Guide roller 18 Suction head 18a Suction head suction port 19 Filter paper drive Roller 20 Tension pulley 21 Belt 22 Filter paper breakage detection switch 23 Suction port 24 Radiation detector 25, 27 First and second clutches 26, 28 Motor 32 Marker bracket 32a Marking line 42 Marker part 43 Mark detection part 44, 45 Filter paper re- Use control unit

Claims (5)

The air at the monitoring point of the radioactive material handling facility is sucked into the airtight space, and the sucked air is wound around either one of the first and second winding means and conveyed. filter paper and provisions time sucked by suction means through a, in radioactive dust monitor the radiation from the dust which is dust collection on the filter paper by suction detected by radiation detection means,
The plate is disposed and fixed facing the surface of the filter paper and has two parallel sides perpendicular to a straight line in the filter paper transport direction, and the width of the two sides is the transport in the dust collection region of the filter paper. Marker means having dimensions at least equal to the width of the direction;
A length of at least the same length as twice the width in the transport direction in the dust collection region as one pitch length, and transport means for transporting the filter paper by one pitch length ;
A filter paper rewinding machine for rewinding the filter paper wound around one of the first and second winding means ;
At the time of setting the filter paper when the filter paper is wound around one of the first and second winding means by the transport means, marking is performed according to one side of the marker means, and then the transport means is used. Each of the first and second winding means is wound while transporting by one pitch length and performing suction by the suction means and radiation detection by the radiation detection means in the dust collection region, and then The marking of the filter paper rewound by the filter paper unwinding machine is aligned with the other side of the marker means, and then conveyed by the pitch by the conveying means, and the suction means is used in the reuse area between the dust collection areas. The radioactive dust monitor characterized by performing the suction | attraction by this and the radiation detection by the said radiation detection means . The width of the two sides of the marker means is a dimension obtained by adding a filter paper transport error to the width in the transport direction in the dust collection area of the filter paper,
The radioactive dust monitor according to claim 1, wherein the one pitch length is a length obtained by adding a filter paper transport error to a length twice the width in the transport direction. The air at the monitoring point of the radioactive material handling facility is sucked into the airtight space, and the sucked air is wound around either one of the first and second winding means and conveyed. filter paper and provisions time sucked by suction means through a, in radioactive dust monitor the radiation from the dust which is dust collection on the filter paper by suction detected by radiation detection means,
A length that is at least the same as twice the width in the transport direction in the dust collection region of the filter paper is defined as one pitch length, and the filter paper is transported by one pitch length to the first and second winding means. A conveying means for performing rewinding after being wound around either one of
A mark is placed on the surface of the filter paper when the filter paper is placed and fixed facing the surface of the filter paper, and when the filter paper is wound around one of the first and second winding means by the conveying means. Marker means for attaching,
Detecting means for detecting a mark attached to the filter paper;
After the filter paper is wound around one of the first and second winding means by the conveying means, the mark position is obtained based on the mark information detected by the detecting means at the time of rewinding. The rewinding of the filter paper is stopped, and the filter paper is transported from the mark position to a length at least equal to the width in the transport direction in the dust collection area, and the reuse area between the dust collection areas is transferred to the suction means. And a control means for controlling the conveying means so as to face each other. The one pitch length is a length obtained by adding a filter paper transport error to twice the width in the transport direction,
The length of the transport from the mark position of the filter paper, which is controlled by said control means, according to claim 3, characterized in that a length obtained by adding the filter paper transport error in the transport direction of width of the dust-collecting area Radioactive dust monitor. The air at the monitoring point of the radioactive material handling facility is sucked into the airtight space, and the sucked air is wound around either one of the first and second winding means and conveyed. In the method of using the filter paper in the radioactive dust monitor, the radiation is sucked by the suction means through the filter paper for a specified time, and the radiation from the dust collected on the filter paper by the suction is detected by the radiation detection means.
A first step of marking the filter paper at the time of setting the filter paper when winding the filter paper on either one of the first and second winding means by the conveying means;
After the mark is attached in the first step, when transporting the filter paper after suction by the suction means, a length at least equal to twice the width in the transport direction in the dust collection area of the filter paper And a second step of transporting the filter paper of the one pitch length.
When the filter paper is rewound and used after being used to the end, from the position of the mark attached in the first step, the length in the dust collection area is at least the same as the width in the transport direction. A third step of conveying the filter paper so that the reuse area between the dust collection areas faces the suction means;
A method for using filter paper in a radioactive dust monitor , comprising :

Images