JP4469669B2 - Method and apparatus for inspecting radioactive contamination - Google Patents

Description

  The present invention relates to a radioactive contamination inspection method and apparatus for inspecting radioactive contamination while loading an article on a conveyor and continuously moving the article.

  In a conventional radioactive contamination inspection device that inspects radioactive contamination while loading articles on a conveyor and continuously moving, the radiation detectors are arranged vertically and horizontally on the conveyor as described in Patent Documents 1 and 2 below. However, this requires a detector with a large area, and there are technical problems such as flattening of the sensitivity distribution. The same applies to the apparatus described in Patent Document 3 in which an article to be inspected is fixed and measured. In a large-area detector, there is a problem that the background count value increases and the detection limit deteriorates. In order to obtain a high detection limit in such a system, the measurement time can only be extended, and the processing amount per unit time is reduced in a normal processing method.

Patent Document 4 describes a radioactive contamination inspection apparatus in which a plurality of detectors are arranged along the flow direction of a conveyor. This is intended to identify a contamination position, and is processed per unit time. The specific configuration and processing method necessary for obtaining a good detection limit while securing the amount are not described.
JP-A-8-166458 JP-A-6-64714 JP 10-319125 A JP2004-020409A

  The present invention provides a radioactive contamination inspection method and apparatus capable of obtaining a good detection limit while ensuring a processing amount per unit time in a radioactive contamination inspection of an inspection object loaded on a conveyor and continuously moving. With the goal.

The invention of claim 1 conveys an object to be inspected and is assigned a number for each predetermined length in the direction of travel, and is arranged along the direction of travel of the conveyor belt and emitted from the object to be inspected. A plurality of radiation detectors that measure radiation, and an information processing, control, and display device that processes the output of the radiation detectors, controls the speed of the conveyor belt, and displays the radioactive contamination status of the inspection object. The configuration is as follows.

The invention according to claim 6 is provided along the traveling direction of the conveyor belt with radiation radiated from the inspected object loaded and moved on the conveyor belt assigned a number for each predetermined length in the traveling direction. The measurement is performed by a plurality of radiation detectors, and the outputs of the plurality of radiation detectors are added according to position information on the conveyor belt.

  According to the present invention, there is provided a radioactive contamination inspection method and apparatus capable of obtaining a good detection limit while ensuring a processing amount per unit time in a radioactive contamination inspection of an inspection object loaded on a conveyor and continuously moving. can do.

Hereinafter, first to sixth embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
As shown in FIG. 1, the radioactive contamination inspection apparatus according to the first embodiment of the present invention is configured to detect radiation on the upper surface of the inspection object 6 and the radiation detectors 1 a to 1 c for measuring the contamination on the lower surface and the contamination on the lower surface. Radiation detectors 2a to 2c, radiation detectors 3a to 3c for measuring contamination on the right side as viewed from the upstream side, radiation detectors 4a to 4c for measuring contamination on the left side, and a conveyor belt 5, a roller 7, and an information processing control display device 8, and inspects radioactive contamination of the inspection object 6. The information processing / control / display device 8 is connected to the radiation detectors 1a to 1c, 2a to 2c, 3a to 3c, and 4a to 4c, and also performs speed control of the conveyor belt 5, display of count values, and the like. .

  The conveyor belt 5 may be formed in a wire mesh shape with respect to the range on which the inspection object 6 is placed, and the lower surface detectors 2a to 2c can be formed by passing the conveyor belt only on both sides and passing a wire or the like between the conveyor belts. Thus, it may be configured to detect contamination by a substance that emits radiation having a low transmission power on the lower surface of the inspection object 6. Moreover, it is good also as a structure which does not have the side surface detectors 3a-3c and 4a-4c, but has only the detectors 1a-1c and 2a-2c of an upper surface and a lower surface, and measures only the upper and lower surfaces of the to-be-inspected object 6. Regarding the direction of the detection surface of the inspection object 6, not only horizontal and vertical directions but also surfaces in other directions may be measured. In FIG. 1, the number of detectors in each direction is three, but it may be more or less.

  According to this configuration, an output appears at each detector as the inspection object 6 moves. As an example, FIG. 2 shows the time variation of counting per unit time associated with the movement of the inspection object 6 of the upper surface detectors 1a to 1c. As described above, the inspection object 6 comes to the front of the effective surface of the detector as the inspection object 6 moves, so that the count by the inspection object 6 can be obtained.

According to the radioactive contamination inspection apparatus of the present embodiment, output is obtained in order to the plurality of radiation detectors 1a to 4c as the inspection object 6 moves.
Therefore, it is possible to obtain a good detection limit while ensuring a processing amount per unit time.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. In the present embodiment, a number is assigned to each position as shown in FIG. 3 on the conveyor belt 5 in the radioactive contamination inspection apparatus of the first embodiment. According to this configuration, for example, the relationship between the position on the conveyor belt corresponding to the detector 1a and time can be obtained as shown in FIG. Therefore, it is possible to obtain the relationship between the respective belt positions facing each detector at each time.

  According to the present embodiment, there is provided a radioactive contamination inspection apparatus capable of obtaining a good detection limit while ensuring a processing amount per unit time in a radioactive contamination inspection of an inspection object loaded on a conveyor and continuously moving. can do.

  In the present embodiment, the position on the conveyor belt is divided into 20. However, the number of divisions may be further increased, and a continuous value such as a length may be replaced with this number.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. In the present embodiment, using the relationship between the time for each of the detectors 1a to 4c employed in the second embodiment and the conveyor belt position facing at that time, steps S1, S2, and S3 as shown in FIG. Process in the flow.

  For example, with respect to the upper surface detector, a register to which the output of the detector 1a is written is determined through the addition destination register determination unit. The addition destination register determination is performed according to the flow of steps S21 and S22 in FIG. Based on the time information at that time and the time / conveyor belt position conversion information obtained in the second embodiment, addition is performed based on the position information on the conveyor belt currently in the measurement range of the detector. The destination register is determined, and the output of the detector 1a at that time is written into the register.

  By adopting such a configuration for the upper surface detectors 1a to 1c, the lower surface detectors 2a to 2c, the right surface detectors 3a to 3c, and the left surface detectors 4a to 4c, a plurality of detections at respective positions on the conveyor belt can be performed. It can be obtained by summing up the counts by the instrument.

  Furthermore, using the position information on the conveyor belt, the detection efficiency for each detector is corrected or the detection efficiency for each position of the detector is corrected, and then the output value of each detector is registered in the corresponding register. You may write to.

  Therefore, according to the present embodiment, the radioactive contamination inspection method capable of obtaining a good detection limit while ensuring the processing amount per unit time in the radioactive contamination inspection of the inspection object loaded on the conveyor and continuously moving, and An apparatus can be provided.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIG. In the present embodiment, a sensor 9 for measuring the shape of the inspection object is provided on the upstream side of the conveyor belt 5, and the measurement information is sent to the information processing / control / display device 8. The detector position moving mechanisms 10a to 10c are driven by the control signal. For convenience of explanation, only the top surface detectors 1a to 1c are described as having the detector position moving mechanisms 10a to 10c. However, the detector moving mechanisms are similarly provided to the detectors in other directions. Also good.

  The information processing / control / display device 8 records the shape of the inspected object 6 together with the conveyor belt position information at that time by the shape measuring sensor 9, and keeps holding it until the same position on the conveyor belt comes next. Further, the information processing / control / display device 8 includes a detector that is moved by the shape of the inspection object 6 at the conveyor belt position relative to the radiation detectors 1a to 1c and the detector position moving mechanisms 10a to 10c at that time. Compare the positions of 1a to 1c, and issue a control signal to the detector position moving mechanisms 10a to 10c so that the distance between the object to be inspected 6 and the radiation detectors 1a to 1c is the shortest in the range where they do not contact each other. Adjust the position.

  According to the present embodiment, the radiation detectors 1a to 1c can always keep the distance from the inspection object 6 as short as possible, and provide a radioactive contamination inspection apparatus that can detect radiation efficiently. be able to.

(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIG. In the present embodiment, the origin marking 11 is provided on the conveyor belt 5 and the origin marking detection sensor 12 is provided on the fixed portion. With this configuration, the position information can be calibrated every time the rotational position of the conveyor belt 5 comes to the origin, so that the position of the inspection object 6 is not displaced and the contamination can be accurately measured.

  In addition, although this Embodiment set it as the structure which detects the one origin marking 11 with the one detection sensor 12, it provides the marking which showed several positional information, and discriminate | determines the several information about the positional information. It may be detected by a single detection sensor capable of performing the above, or a plurality of detection sensors may be provided.

(Sixth embodiment)
Next, a sixth embodiment will be described with reference to FIGS. 9 and 10. In the present embodiment, the position where the radiation detectors 1 a to 4 c are arranged is determined as the measurement end area 13.

  FIG. 10 is an example of a graph showing the upper surface contamination status displayed on the information processing / control / display device 8. The horizontal axis indicates the position on the conveyor belt, and the vertical axis indicates the cumulative count. The vertical line indicating the range corresponding to the radiation detector and the extraction area moves to the right side as the conveyor belt moves, and moves to the left end when it reaches the right end. Further, after passing the take-out area, the register corresponding to the position on the conveyor belt is reset to the initial value. At this time, the value is stored in a log file or the like before resetting, and the value is processed, controlled, and controlled as a radioactive contamination inspection history value of articles taken out from the takeout area at the time after the takeout area ends. You may display on the display apparatus 8. FIG.

  According to the present embodiment, it is possible to provide a radioactive contamination inspection apparatus that evaluates contamination based on the cumulative count of the inspected object 6 that has appeared in the extraction area after completion of the contamination inspection measurement by a series of radiation detectors. .

The structure of the radioactive contamination inspection apparatus of the 1st Embodiment of this invention is shown, (a) is an elevational view which follows the AA 'line of (b), (b) is BB' of (a). The top view which follows a line. The figure which illustrates the count output of the radiation detector with respect to elapsed time, and demonstrates the effect | action of the radioactive contamination inspection apparatus of the 1st Embodiment of this invention. The structure of the radioactive contamination inspection apparatus of the 2nd Embodiment of this invention is shown, (a) is an elevation view, (b) is a top view. The curve figure which shows the relationship between the position on the conveyor belt equivalent to a radiation detector, and time, and demonstrates the effect | action of the radioactive contamination inspection apparatus of the 2nd Embodiment of this invention. The figure which shows the flow of the contamination degree measurement of the to-be-inspected object upper surface in the radioactive contamination inspection apparatus of the 3rd Embodiment of this invention. The figure which shows the flow of a process of the count data of the radiation detector in the radioactive contamination inspection apparatus of the 3rd Embodiment of this invention. The elevation view which shows the structure of the radioactive contamination inspection apparatus of the 4th Embodiment of this invention. The top view which shows the structure of the radioactive contamination inspection apparatus of the 5th Embodiment of this invention. The top view which shows the structure of the radioactive contamination inspection apparatus of the 6th Embodiment of this invention. The curve figure which illustrates the operation | movement effect | action of the radioactive contamination inspection apparatus of the 6th Embodiment of this invention which illustrates the contamination condition measurement result of the to-be-inspected object upper surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a-1c ... Upper surface detector, 2a-2c ... Lower surface detector, 3a-3c ... Right surface detector, 4a-4c ... Left surface detector, 5 ... Conveyor belt, 6 ... Inspection object, 7 ... Roller, 8 ... Information Processing / control / display device, 9 ... shape measurement sensor, 10a to 10c ... detector position moving mechanism, 11 ... origin marking, 12 ... origin marking detection sensor, 13 ... measurement end area.

Claims (6)

A conveyor belt that conveys the object to be inspected and is assigned a number for each predetermined length in the direction of travel, and a plurality of radiation belts that are arranged along the direction of travel of the conveyor belt and that radiate from the object to be inspected A radiation detector; and an information processing / control / display device that processes an output of the radiation detector, controls a speed of the conveyor belt, and displays a radioactive contamination status of the inspection object. Radioactive contamination inspection equipment.   3. The radioactive contamination inspection apparatus according to claim 2, wherein the information processing / control / display apparatus adds the output of the radiation detector to a corresponding register area according to position information on the conveyor belt.   A shape measuring sensor provided at the most upstream portion of the conveyor belt for measuring the shape of the object to be inspected, and a detector position moving mechanism for moving the position of the radiation detector according to output information of the sensor. The radioactive contamination inspection apparatus according to claim 1, wherein   The radioactive contamination inspection apparatus according to claim 1, further comprising an origin marking provided on the conveyor belt and a detection sensor that detects the origin marking.   The radioactive contamination inspection apparatus according to claim 1, further comprising a measurement end area provided in a downstream portion of the flow of the conveyor belt. A plurality of radiation detectors provided along the traveling direction of the conveyor belt are used to radiate radiation radiated from an object to be inspected that is loaded and moved on a conveyor belt assigned a number for each predetermined length in the traveling direction. A radioactive contamination inspection method comprising: measuring and adding outputs of the plurality of radiation detectors according to position information on the conveyor belt.

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