JP2010054447A - Device for monitoring radioactive iodine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein cartridges for catching radioactive iodine need be scrapped, even if the conventional radioactive iodine monitors are used, in an environment where radioactive iodine is not contained and iodine is not caught. <P>SOLUTION: Even if a cartridge A1 before purification in a radioactive iodine monitoring device adsorbs radioactive radon and thoron, together with water vapor contained in a sample air SA caught in a catching part B3, dry air DA heated and dried in a purifying part D3 or dry gas from a high pressure gas bomb is sprayed on the cartridge A1 to remove them so as to be purified, and thereby repetition of reuse is enabled thereafter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radioactive iodine monitoring device, and particularly suitable for measuring the concentration of radioactive iodine that may be contained in the atmosphere in a nuclear facility or a surrounding area, and chemically collecting radioactive iodine. The present invention relates to a radioactive iodine monitor device capable of repeatedly using a cartridge containing a trapping material.

  As a conventional monitoring technique for reusing a radioactive material collection material, a dust radiation monitor described in Patent Document 1 described below is known. The monitor collects dust with filter paper to detect the concentration of radioactive dust in the air, blows air on it to recycle the collected filter paper, and blows off the adhering dust. The amount is lowered.

Japanese Patent Laid-Open No. 10-132943

  In Patent Document 1, since dust is only physically attached to the filter paper, it can be removed by blowing off air by blowing air. On the other hand, in the cartridge for collecting radioactive iodine, there is a problem that radioactive substances such as iodine are easily removed by wind pressure because of the chemical reaction with the collecting material.

  In addition, conventional iodine monitors are used in environments that do not contain radioactive iodine and adsorb moisture present in the gas under test together with radioactive radon and thoron that exist in nature, even if no iodine is collected. Therefore, because the adsorbed moisture lowers the subsequent iodine collection efficiency, it cannot be used as a collection material, and the cartridge once used must be discarded and cannot be recycled in consideration of environmental problems. There was a point.

  This invention solves the above problems, and makes it a subject to make it reusable about the said cartridge which is used in the environment which does not contain radioactive iodine, and does not collect radioactive iodine. It is.

  The present invention has been made in order to solve the above-described problems, and is a breathable cartridge containing a collecting material that chemically collects radioactive iodine present in the gas to be inspected, and the gas to be inspected. A gas supply device that supplies the cartridge, a radioactive iodine quantification device that quantifies the amount of radioactive iodine collected by the collection material by measuring iodine radioactivity, and the collection material in the cartridge after the quantification. The present invention provides a radioactive iodine monitor device comprising a drying device that dries with a dry gas.

  According to the radioactive iodine monitor device of the present invention, moisture collected together with the radioactive substance in the cartridge is dried and removed by the drying device. Since the removal efficiency of the radioactive iodine in the cartridge returns to the level before use by removing the water, it can be recycled. Moreover, since the removal of moisture is performed immediately after use, the removal efficiency is excellent. Further, in the radioactive iodine monitoring device of the present invention, the collection material is accommodated in a breathable cartridge, and the cartridge is easy to handle individually. Moisture removal is possible, thereby improving the efficiency of the moisture removal process. Therefore, the cartridge can be used over and over again for collection in an environment that does not contain radioactive iodine.

Note radioactive radon and thoron described above, since a short decay time of Fortunately radioactivity, i.e., for example, half-life in radon ²²² Rn is 3.8235 days, a half-life 55.6 seconds Tron ²²⁰ Rn, they Since the half-life of the daughter nuclide is extremely short, it returns to the level before use after being left for a short time. Further, as will be described later, when the cartridge once used is dried by blowing dry air, these radioactive substances are removed together with the adsorbed moisture. Therefore, the cartridge can be used any number of times by leaving it for a short period of time, or by blowing dry air together with the leaving. For this reason, the iodine monitor provided with the recycling function in consideration of the environmental problem can be provided.

Embodiment 1 FIG.
1 to 6 illustrate the first embodiment of the present invention. FIG. 1 is an explanatory diagram illustrating a cartridge A1 and a storage cylinder A that stores a plurality of cartridges A1, and FIG. FIG. 3 is an explanatory view of a gas supply device B that supplies the inspection gas to the cartridge A1, FIG. 3 is an explanatory view of a detector C as an example of the radioactive iodine determination device, and FIG. 4A is an explanatory diagram of the entire drying apparatus D, FIG. 4B is an explanatory diagram illustrating a process of drying the cartridge A1, and FIG. 5 is a used cartridge. FIG. 6 is an explanatory view of a cartridge disposal box E as an example of the cartridge housing device that temporarily stores A1 for the purpose of reuse. FIG. 6 shows the devices shown in FIGS. State It is to illustration.

  In FIG. 6, the turntable F has four depressions F1 to F4 and is rotatable in the direction of the arrow X around the center of the table. Further, a gas supply device B, a detector C, a drying device D, and a cartridge disposal box E are installed around the turntable F. FIG. 6 shows that the cartridge A1 in the gas supply device B exists at the position of the depression F1. The cartridge A1 that is detected by the detector C is present at the position of the depression F2, the cartridge A1 that is dried and purified by the drying device D is at the position of the depression F3, and the cartridge A1 that is dried and purified by the drying device D is the cartridge A1. A state where the cartridge is dropped into the cartridge disposal box E from the depression F4 is shown.

  1 and 6, the cartridge A1 is a disc-shaped object having a breathable net (only the upper surface is shown in FIG. 1 and the like) on both surfaces, and the radioactive iodine present in the gas to be inspected therein. Contains a collection material that chemically collects the material. The collecting material is a filter paper adsorbed with activated carbon such as granular charcoal or crushed charcoal described in JIS-Z4336 annex "filter medium for iodine collection". In which about 5% by weight or about 10% by weight is added, and it is commercially available as CHC-50. A plurality of cartridges A1 having such a structure are stacked and stored in the storage cylinder A until they are used.

  The storage cylinder A is placed near the gas supply device B as shown in FIG. 6, and the cartridge A1 in the storage cylinder A is pushed out one by one from the lower part of the storage cylinder A when used, and gas is supplied by the transport device A2. Supplied to device B. Note that the cartridge A1 in the storage cylinder A may be extruded by a well-known extrusion method and supplied to the gas supply device B instead of the transport device A2.

  2 and 6, the gas supply device B includes an introduction pipe B1 for introducing the sample air SA, an exhaust pipe B2 for discharging the sample air SA, and a collection part B3 provided between the two pipes. Has been. The introduction pipe B1 has an inlet B11 for sucking the sample air SA at one end, and a disk body part B12 for airtightly fixing the cartridge A1 is formed at the other end. The exhaust pipe B2 has an exhaust port B21 for exhausting the sample air SA at one end thereof, and a disc body portion B22 for airtightly fixing the cartridge A1 is formed at the other end, and the exhaust port B21 and the disc body portion B22 are formed. And a suction pump B23 for sucking the sample air SA. The introduction pipe B1 and the exhaust pipe B2 can be moved relative to each other in the direction of the arrow Y (see FIG. 6), and the cartridge A1 is detachable between the disk body B12 and the disk body B22 by this relative movement. And it is airtightly clamped. Hereinafter, the whole of the disc body portion B12, the cartridge A1, and the disc body portion B22 by this clamping is referred to as a collection portion B3. Radioactive iodine, moisture, radon, throne, etc. contained in the sample air SA collected from the suction port B11 and discharged from the exhaust port B21 are collected in the collection unit B3, more specifically, the cartridge A1 contained in the collection unit B3. It is collected by the said collection material.

  3 and 6, the cartridge A1 that has obtained the supply of the sample air SA by the gas supply device B is released from clamping between the introduction pipe B1 and the exhaust pipe B2, and is inspected (not shown) in the depression F2. The amount of radioactive iodine is quantified by detector C.

  4A and 6, the drying device D includes an introduction pipe D1 that introduces dry air DA as an example of the dry gas, an exhaust pipe D2 that discharges air after performing the drying action, and both It consists of a purification section D3 provided between the pipes D1 and D2, a discharge pump D4 and a heater D5 provided in the introduction pipe D1. The introduction pipe D1 has a suction port D11 for sucking dry air DA at one end, and a disk body part D12 for airtightly fixing the cartridge A1 is formed at the other end. The exhaust pipe D2 has an exhaust port D21 for exhausting air after having a drying function at one end, and a disk body portion D22 for fixing the cartridge A1 in an airtight manner is formed at the other end.

  The introduction pipe D1 and the exhaust pipe D2 can be moved relative to each other in the direction of the arrow Y (see FIG. 6), and the purifying section D3 detachably attaches and fixes the cartridge A1 to and from both surfaces. It consists of a disk body part D12 and a disk body part D22. Thus, the dry air DA introduced from the suction port D11 is heated by the heater D5 to further reduce the relative humidity, in other words, the drying function is enhanced, and then the cartridge is passed through the cartridge A1 in the purification unit D3. The trapping material in A1 is dried, and air having a drying function is exhausted from the exhaust port D21 to the atmosphere. In FIG. 6 and subsequent FIG. 8 and subsequent figures, the disk body D22 is not shown in order to avoid complication of the drawing.

  As described above, the cartridge A1 before purification contains the moisture contained in the air SA taken in the collection part B3, radioactive substances such as radon and thoron, and a part of the air SA. Therefore, by spraying heated dry air DA onto the cartridge A1 installed in the purification unit D3, as shown in a simulated manner in FIG. 6B, it is more preferable to reverse the direction in which the sample air SA has passed. By spraying in the direction, it is possible to remove residual sample air SA, moisture collected by the collection material, and radioactive substances such as radon and thoron. The thus-dried cartridge A1 having the collecting material is once discarded in a cartridge disposal box E for temporarily storing used cartridges, and then repeatedly reused. In the present invention, the dry air may be of any low relative humidity that can achieve the necessary drying. For example, if the relative humidity of the gas to be inspected is X%, air having a lower relative humidity, for example, about (1/2) X% or other gas has a drying action.

Embodiment 2. FIG.
FIG. 7 is an explanatory diagram for explaining the second embodiment of the present invention. The second embodiment is different from the first embodiment in that the number of depressions provided in the turntable F is reduced by one and three depressions F1 are provided. To F3, and the cartridge disposal box E is omitted, and the rest is the same as in the first embodiment. Therefore, three bodies of the gas supply device B, the detector C, and the drying device D are provided around the turntable F, and each of the three depressions F1 to F3 has one cartridge A1 and only three in total. The difference is that the gas supply device B, the detector C, and the drying device D are repeatedly circulated, and the others are the same as those in the first embodiment.

  The operation of the second embodiment will be described with reference to FIG. 7. The sample air collecting process by the gas supply device B, the iodine concentration detecting process by the detector C, and the purification process by the drying device D are taken around the turntable F. Only 3 processes. When the purification process is completed, the following new process is followed by the sample air collecting process by the gas supply device B and the operation is repeated.

  According to the second embodiment, only three cartridges A1 are required, and the same effect as that of the first embodiment is obtained. Furthermore, since only three cartridges A1 are required, it is economical, and the cartridge supply process and the disposal process can be omitted, so that the radioactive iodine monitor device of the present invention can be miniaturized.

Embodiment 3 FIG.
FIG. 8 is an explanatory diagram for explaining the third embodiment of the present invention. In the third embodiment, conversely to the second embodiment, the number of depressions F1 to F8 is increased by increasing the depressions on the turntable F. FIG. In each of the depressions F1 to F8, cartridges A1 and eight cartridges A1 are installed (however, the cartridges A1 in the depressions F4 to F8 are not shown). For each cartridge A1, as in the case of the second embodiment, three steps of the sample air collecting process by the gas supply device B, the iodine concentration detection process by the detector C, and the purification process by the drying device D are performed. In the next operation, the same three processes as described above are performed for the three cartridges A1 of F2 to F4, and then the three processes are performed for the three cartridges of F3 to F5. Therefore, in the third embodiment, only three of the eight cartridges A1 are used, and the remaining five are in a resting state. This resting state secures the decay time of radon and tron collected by the trapping material. It functions as a decay time securing means for

  Since the third embodiment has the means for ensuring the decay time as described above, an excellent effect is obtained in that the safety of repeated use of each cartridge A1 is increased. In general, it is preferable to secure a time sufficient for the above-mentioned radioactivity to decay sufficiently, and this decay time is preferably longer than the time for the sample air collection process and the time for the iodine concentration detection process. For this reason, as shown in FIG. 8, the purification process is provided for the same time as the other two processes, but a pause time is provided after the purification process until the sample air collecting process is started. This pause time increases in proportion to the number of cartridges A1 exceeding three. Specifically, it is preferable that the installation time on the side not including the detector C of the drying device D and the gas supply device B installed around the turntable F corresponds to at least 8 hours. This is the time obtained by subtracting the standard waiting time before measurement (which is at least 3 hours) from the Radon-Tron β ray decay time (11 hours). In FIG. 8, five dormant states are illustrated, but in the present invention, it may be sufficient if the above decay time is secured in one dormant state.

  According to the third embodiment, the same effect as the second embodiment in which only three cartridges A1 are provided, but the decay time of radioactivity can be increased as the number of the cartridges increases more than in the second embodiment. It is possible to provide an iodine monitor that can reduce the influence of the previous collection during the next collection and detection, and can perform more accurate measurement.

Embodiment 4 FIG.
FIG. 9 is an explanatory diagram for explaining the fourth embodiment of the present invention. The fourth embodiment is different from the second embodiment in that the suction pump B23 provided in the exhaust pipe B2 and the discharge pump D4 provided in the introduction pipe D1 in the second embodiment are removed, and the exhaust pipe B2 is exhausted instead. The difference is that the port B21 (see FIG. 2) and the suction port D11 (see FIG. 4) of the introduction pipe D1 are directly connected to each other, and the suction pump D7 is provided in the exhaust pipe D2. In the first to third embodiments, each of the sample air collection and purification processes has an intake port and an exhaust port, and both the processes are independent of each other. The air collection process and the purification process are unified.

  Embodiment 4 will be described with reference to FIG. Portions other than the sample air collection process and the purification process are the same as those described in the first to third embodiments. The exhaust air (sample air SA) in the sample air collection process is transferred from the exhaust pipe B2 to the introduction pipe D1 by the suction action by the suction pump D7 and used for the purification process. At that time, the sample air SA discharged from the exhaust pipe B2 increases in water content by depriving the water contained in the cartridge A1 when passing through the cartridge A1, but is heated when it passes through the heater D5. Since the relative humidity decreases and the drying performance increases, the purification function can be achieved in the purification unit D3.

  Therefore, according to the fourth embodiment, it is not necessary to have a dedicated air system for each of the sample air collection process and the purification process, and only one detector C is required. For this reason, the iodine monitor with a small apparatus size which can simplify an apparatus and reduced cost can be provided.

Embodiment 5 FIG.
FIG. 10 is an explanatory diagram for explaining the fifth embodiment of the present invention. In the fifth embodiment, the suction port D11 (not shown) of the introduction pipe D1 is used instead of the discharge pump D4 in the first embodiment. 1), except that the high pressure gas cylinder D6 is directly connected, and the others are the same. As the high-pressure gas cylinder D6, there is no particular limitation on the type of filling gas, and for example, inexpensive high-purity nitrogen is preferable. In general, the high-pressure gas in the high-pressure gas cylinder is a dry gas whose moisture content is close to zero even at room temperature, so that the cartridge A1 wet in the sample air collecting process is dried even if it is used without being heated. In addition, the dust contained in the sample air SA attached to the surface of the cartridge A1 and the collection material that chemically collects radioactive iodine can be blown off and removed, so the number of times the cartridge A1 is used and recycled Can be further increased to provide an iodine monitor that reduces the cost of the cartridge A1.

Embodiment 6 FIG.
FIG. 11 is an explanatory view for explaining the sixth embodiment of the present invention, and is an explanatory view of a cartridge disposal box G used in the same embodiment. In FIG. 11, a cartridge waste box G includes a shutter G2 that opens and closes a charge / discharge port G1 for loading and discharging the cartridge A1, a flat plate heater G3 provided below the bottom of the waste box G, and the waste box. It has a tape heater G4 wound on the outer surface of G. The waste box G has an introduction pipe G5 having an introduction port G51 for introducing a dry gas, an exhaust port G61 for discharging a dried gas, and an exhaust pipe G6 having a suction pump G62.

The cartridge disposal box G shown in FIG. 11 may be employed instead of the corresponding box E employed in the first to fifth embodiments, or may be juxtaposed with the corresponding box E. In any case, according to the sixth embodiment, the drying device D employed in the first to fifth embodiments can be eliminated, and the cartridge G can be dried by the box G instead. Further, as one of the processes for turning around the turntable F to the iodine monitor that does not have the purification function currently used in this field, it is possible to modify the apparatus by adopting the drying apparatus D employed in the first to fifth embodiments. However, the box G according to the sixth embodiment only needs to be replaced with the above-described box bait E having no purification function, which greatly reduces the remodeling cost. There is a contributing effect. In the sixth embodiment, the discharge pump D4 used in the first embodiment may be used instead of the suction pump G62 provided in the discharge pipe G6.
Embodiment 7 FIG.

  FIG. 12 is an explanatory diagram for explaining the seventh embodiment of the present invention. In the seventh embodiment, the disk body of the exhaust pipe B2 is replaced with the heater D5 provided in the introduction pipe D1. A heater B4 is provided downstream of the part B22, and the exhaust pipe B2 and the introduction pipe D1 are different in that they are connected via a cylinder H provided at the upper part of the cartridge disposal box E. Further, the upper end of the cylindrical body H is located below a recess F4 provided in the turntable F, and the lower end thereof is airtightly connected to the cartridge disposal box E. Opening and closing devices H1 and H2 such as shutters are provided above and below the cylindrical body H. Have Therefore, the cartridge A1 passing through the drying device D is taken into the cylindrical body H with the opening / closing device H1 opened and the opening / closing device G2 closed, and when the opening / closing device H1 is subsequently closed, the cartridge is discarded between the cartridge A1. An isolation space H3 isolated from the box E can be used. The isolation space H3 is an example of the second cartridge storage device. Thereafter, when the opening / closing device G2 is opened, the cartridge A1 accommodated therein is dropped into the cartridge disposal box E.

  After completion of the purification process in the turntable F, the cartridge A1 is once isolated in the isolation space H3 by operating the opening / closing devices H1 and H2 before being put into the cartridge disposal box E. In this state, the sample air SA introduced from the suction port B11 passes through the cartridge A1 installed in the gas supply device B and is purified by removing moisture, radon, and the like. The drying power is improved by heating by the heater B4, and then the cartridge A1 in the isolation space H3 can be dried by passing through the isolation space H3 and the purification section D3.

  Since the cartridge A1 in the isolation space H3 has already been dried in the purification unit D3 in the turntable F, the cartridge A1 is dried in two stages in the seventh embodiment, so that the degree of drying is further improved. This makes it possible to increase the iodine collection efficiency at the time of reuse as well as a new product. Further, after the filter portion of the cartridge A1 is concentrated and dried, the frame portion other than the filter portion can be dried, and finish drying is performed, so that the purification finish is good. In addition, since the used cartridge disposal box E is always isolated, the cartridge A1 that has been purified at any time can be taken out from the disposal box E.

  The present invention may be used as a monitoring device for radioactive iodine that may be contained in the atmosphere in or around a nuclear facility.

FIG. 3 is an explanatory diagram illustrating a cartridge and a storage cylinder that stores a plurality of cartridges in the first embodiment. It is explanatory drawing of the gas supply apparatus which supplies the to-be-inspected gas in Embodiment 1 to a cartridge. FIG. 3 is an explanatory diagram of a detector in the first embodiment. FIG. 3 is an explanatory diagram of a drying device in the first embodiment. 4 is an explanatory diagram of a cartridge disposal box that temporarily stores used cartridges in Embodiment 1. FIG. It is explanatory drawing which shows the state which installed each apparatus shown in FIGS. 1-5 in Embodiment 1 around a turntable. It is explanatory drawing of arrangement | positioning of the gas supply apparatus in Embodiment 2, a detector, a drying apparatus, and a turntable. It is explanatory drawing of arrangement | positioning of the gas supply apparatus in Embodiment 3, a detector, a drying apparatus, and a turntable. It is explanatory drawing which shows the connection state of the gas supply apparatus in Embodiment 4, and a drying apparatus. FIG. 10 is an explanatory diagram of a usage state of a high-pressure gas cylinder in a fifth embodiment. FIG. 20 is an explanatory diagram of a cartridge disposal box in the sixth embodiment. It is explanatory drawing of the cylinder in Embodiment 7, and isolation space.

Explanation of symbols

A: Storage cylinder, A1: Cartridge, A2: Extrusion mechanism, B: Gas supply device,
B1: introduction pipe, B11: suction port, B12: disk body, B2: exhaust pipe, B21: exhaust port,
B22: disk body part, B23: suction pump, B3: collection part, B4: heater, C: detector,
D: Drying device, D1: Introduction pipe, D11: Suction port, D12: Disc body, D2: Exhaust pipe,
D21: exhaust port, D22: disk body part, D3: purification part, D4: discharge pump, D5: heater,
D6: high pressure gas cylinder, D7: suction pump, E: cartridge waste box,
F: Turntable, F1-F4: Recess, G: Cartridge disposal box,
G1: loading / unloading port, G2: shutter, G3: flat plate heater, G4: tape heater,
G5: introduction pipe, G51: introduction port, G6: discharge pipe, G61: discharge port, G62: suction pump, H: cylinder, H1: switchgear, H2: switchgear, H3: isolation space, SA: sample air,
DA: Dry air.

Claims (10)

  A gas-permeable cartridge containing a collecting material that chemically collects radioactive iodine present in the gas to be inspected, a gas supply device for supplying the gas to be inspected to the cartridge, and the gas collected by the collecting material A radioactive iodine quantification device for quantifying the amount of radioactive iodine by measuring iodine radioactivity, and a drying device for drying the trapping material in the cartridge with a dry gas after the quantification. Monitor device.   2. The radioactive iodine monitor according to claim 1, further comprising a circulation moving device that circulates and moves the three cartridges in the order of the gas supply device, the radioactive iodine determination device, and the drying device. apparatus.   3. The radioactive iodine monitor according to claim 2, wherein the circulation moving device is a turntable that supplies the cartridge to the gas supply device, the radioactive iodine determination device, and the drying device fixed at a predetermined position. apparatus.   When the cartridge dried by the drying device is supplied to the gas supply device, the cartridge has a decay time securing means for securing the decay time of radon and thoron collected by the trapping material. The radioactive iodine monitor device according to any one of claims 1 to 3.   The decay time securing means is configured so that the installation time on the side of the drying device and the gas supply device installed around the turntable on the side not including the radioactive iodine determination device corresponds to at least 8 hours. The radioactive iodine monitoring apparatus according to claim 4.   The dry air is supplied from a high-pressure gas cylinder, and the high-pressure gas cylinder sprays the dry gas onto the collection material in the cartridge to dry the collection material and at the same time adheres to the collection material. The radioactive iodine monitor apparatus according to any one of claims 1 to 5, wherein dust can be removed.   7. The radioactive iodine monitor device according to claim 1, further comprising a cartridge storage device that temporarily stores the cartridge dried by the drying device for the purpose of reuse.   8. The cartridge storage device includes an opening / closing device capable of making an inlet / outlet for inserting / removing a stored cartridge airtight, and a gas exchange device for replacing a gas inside the cartridge storage device with a new gas. The radioactive iodine monitoring device described in 1.   A connecting pipe for connecting the exhaust port of the gas supply device and the gas inlet of the drying device, and the connecting tube temporarily stores a cartridge dried by the drying device for reuse. The two cartridge accommodating devices are connected, and the gas discharged from the gas supply device is sent to the drying device via the second cartridge accommodating device. The radioactive iodine monitoring device according to claim 1.   The radioactive iodine monitor apparatus according to any one of claims 1 to 9, wherein the gas to be inspected is an atmosphere in a nuclear facility or a region around the nuclear facility.

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