JPS624670B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dust radiation concentration monitoring device, and more particularly to a dust radiation concentration monitoring device that efficiently and accurately monitors the radiation concentration of dust in the air of a nuclear power plant or the like.

FIG. 1 shows an example of the configuration of a conventional dust radiation concentration monitoring device, in which radioactive dust from sampling points S ₁ to _{S o} to be measured is transferred to piping 7.
1 to 7n and the selection valves 21 to 2n by the suction pump 4, the radiation dust on the filter paper 5 in the dust sampler 3 is collected, and the concentration is detected by the radiation detector 6 surrounded by the shield body 14. , preamplifier 1
0, measured by the control unit 13 via the counting rate module 12. With this operation, sampling point S ₁
~S _o is selected by sequentially switching the selection valves 21 to 2n at a constant cycle under control from the control unit 13,
The filter paper 5 is moved by the filter paper feeding mechanism 11 at each switching time. Further, before switching, dust from the previous sampling point is discharged to the outside via a purge valve 8 and a filter 9.

In this way, if the dust sampler 3, the control unit 13, etc. are concentrated and fixed in one place, it is called a fixed type.In this fixed type, the concentration of the detected radiation is on the inner wall of the sampling pipes 71 to 7n. It is rated low due to dust adhesion to etc.

In order to reduce such dust collection loss, there is also a portable type in which a concentration detection section can be connected near the sampling point, which is shown in FIG. This is done by adding a quick connector 15 near the sampling point to the configuration shown in FIG. In the figure, connect to _S1 ),
The concentration is continuously detected by suctioning through a selection valve (valve 21A in case of _S1 ) using a dedicated portable measuring suction pump 4A.

However, when using this portable type, there was no established control method for each selection valve, and measures such as stopping measurements at other sampling points were taken when measuring with the portable type. .

The present invention has been made in view of the problems of the prior art described above, and its purpose is to enable measurements to be performed on all sampling points by selecting between fixed and portable measurements for each sampling point. To provide a dust radiation concentration monitoring device.

The present invention includes a selection means for selecting whether to measure each sampling point in a fixed form or a portable form; The present invention is characterized in that it is provided with a control mechanism that performs high-precision measurement and performs conventional sampling measurement at sampling points selected for fixed measurement.

Hereinafter, the present invention will be explained in detail with reference to Examples.
FIG. 3 shows an embodiment in which the present invention is implemented using a microprocessor, in which a fixed sampling point selection switch panel 18 and a portable sampling point selection switch panel 19 each perform the following functions.
Which point is selected as fixed or portable is determined by the DI signal 200 (this signal line
(consisting of books) into the processor (CPU) 23. In the CPU 23, the suction pumps 4, 4A, selection valves 21~2n, 21A~2 are activated by the DO signal 201 corresponding to the selected point.
Controls nA, etc.

FIG. 4 is a schematic diagram showing one method of the processing flow in the CPU 23.
When it is determined that there is a request for measurement in a portable type, fixed type processing 100 and portable type processing 200 are repeated alternately, and when there is no request, only fixed type processing 100 is repeated.

If we look at this as a task configuration, it becomes as shown in FIG. 5. That is, the monitoring task 24 (judgment process 3
00) constantly monitors the DI signal 200, identifies which sampling points are selected as fixed or portable, and sends this information to the portable control task 25 (corresponding to process 200) and the fixed control task. 26 (corresponding to process 100). In the portable control task 25, the portable control task 25 performs control to continuously measure one point selected as portable, and in the fixed control task 26,
The fixed type is controlled to perform measurements while scanning the selected points as in the conventional method. Therefore, apparently tasks 25 and 26 operate independently and in parallel, making it possible to measure two points at the same time, making it possible to centrally monitor one selected point in a portable manner. Also, if you do not select the portable type and select all the points as fixed type, it can also be used as a conventional fixed type.

Next, the contents of each of the above processes 100 and 200 will be described in detail. FIG. 6 is a flowchart showing the contents of the fixed type processing 100, and it is assumed that sampling points selected as fixed type are set in advance by the DI signal 200. First, in step 1001, the purge valve 8 is opened, the suction pump 4 is started, and in step 1002, the filter paper feed mechanism 11 is driven to move the filter paper 5 a certain length, and the sampling point selected as a fixed type by the DI signal 200 is set. 1 of the selection valves
One is opened in step 1003. (in this way
A DO signal 201 is output at each step. Same below).

Next, the measurement starts, and the purge valve 8 is closed in step 1004, and the AI signal 202 from the radiation detector 6 is taken in in step 1005.
The process is continued until it is confirmed in step 006 that the data has been captured continuously for the sampling time. This is because the AI signal has temporal fluctuations, so it is averaged over a fixed time width. When the acquisition of the AI signal 202 is completed, in step 1007, the selection valve of the sampling point selected so far is closed and the purge valve is opened, and in step 1008, the average concentration is converted and displayed or recorded. Subsequently, the filter paper is moved in step 1009 for the next measurement, and the filter paper is moved in step 10.
The selection valve of the next selected sampling point is opened in step 100, and the process returns to step 1004, whereupon the concentration is calculated in the same manner. This cycle is repeated for selected sampling points in sequence.

FIG. 7 is a flowchart showing the contents of the portable processing 200. Prior to this processing, the DI signal 200 is
It is assumed that one sampling point portably selected by is set in advance. First, in step 2001, the solenoid valve at the sampling point designated as portable is opened, and the pump 4A (FIG. 2) is started. step 2002
Now move the filter paper and go to step 2003, 200.
4, the AI signal 202 is captured for a certain period of time (same as steps 1005 and 1006 in FIG. 6),
Next, in step 2005, the average density is calculated, and the process returns to step 2002, in which the filter paper is moved. Since this process continuously measures the same sampling point, the repeat loop does not include the opening and closing of the selection valve and purge valve as shown in Figure 6. The valve is opened and closed. (not shown).

In FIG. 8, one selection switch panel is used instead of the selection switch panels 18 and 19 for fixed type and portable type in the embodiment of FIG. 3, and one selection switch panel is used for each sampling point. An alternative switch is provided. Then, normally, fixed type control is performed, and if the portable type is selected, only one point is subjected to portable type control (process 200), and the other points are fixed type control (process 100), and the portable type is selected. Only points are excluded from the scan target.

As is clear from the above embodiments, according to the present invention, for each sampling point, a portable type control or a fixed type control is selected, and in parallel with high-precision measurement by the portable type, the fixed type control of other points is Therefore, if a portable type is selected for sampling points that need to be measured with high precision, efficient measurements can be made.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional dust radiation concentration monitoring device, Figure 2 is a configuration diagram with a portable concentration detection unit added, and Figure 3 is a schematic diagram showing an embodiment of the present invention realized by a microprocessor. , FIG. 4 is a schematic operational flowchart of the present invention, FIG. 5 is a diagram showing a schematic task configuration of the present invention, FIG. 6 is a detailed operational flowchart of fixed type processing, and FIG. 7 is a detailed operational flowchart of portable type processing. The operation flowchart, FIG. 8, is a schematic diagram of a switch panel according to a modification of the present invention. S ₁ ~ _{S o} ...Sampling point, 21~2
n, 21A~2nA...Selection valve, 3...Fixed dust sampler, 3A...Portable dust sampler, 4,4
A...Suction pump, 5,5A...Filter paper, 6,6A...Radiation detector, 71-7n...Sampling piping, 8
...Purge valve, 9...Filter, 10,10A...Preamplifier, 11,11A...Filter paper feeding mechanism, 12,1
2A... counting rate module, 13... control section, 15...
Quick connector, 18...Fixed sampling point selection switch panel, 19...Portable sampling point selection switch panel, 23...
CPU, 24... Monitoring task, 25... Portable control task, 26... Fixed control task.

Claims (1)

[Claims] 1. A first collection means for collecting dust in the air sucked by a suction means from a plurality of measurement points through piping and a first selection valve provided corresponding to the measurement points, and the collection means. a fixed dust sampler equipped with a first detection means for detecting the radiation concentration of the collected dust; and a fixed dust sampler that can be inserted in series in the vicinity of the measurement point of the piping and is provided corresponding to the measurement point separate from the selection valve. a second selection valve and a second collection means for collecting dust in the air sucked through a suction means different from the suction means, and detecting the radiation concentration of the collected dust. a portable dust sampler equipped with a second detection means; a selection setting means for setting a first measured point to be measured by the fixed dust sampler and a second measured point to which the portable dust sampler is connected; For the first measurement point, the radiation concentration is detected cyclically by the fixed dust sampler by sequentially opening the first selection valve corresponding to the measurement point one by one, and control means for controlling a second point to be measured so that the second selection valve corresponding to the point to be measured is opened and the radioactivity concentration thereof is continuously detected by the portable dust sampler; A dust radiation concentration monitoring device characterized by comprising: