JP4488195B2 - Radioiodine sampler and radioiodine monitor having the same - Google Patents

Description

  The present invention relates to a radioactive iodine sampler that samples iodine and its compounds from the air in a nuclear facility such as a nuclear power generation facility and a nuclear fuel cycle facility and for detection of radioactive iodine released from the facility to the environment. The present invention relates to a radioactive iodine monitor.

  Radioiodine monitors that measure air released from nuclear power generation facilities, etc., normally sample air continuously, and by providing a heater upstream of the iodine scavenger in the air flow path, sampling is performed. The heated air is heated to prevent moisture absorption by the iodine scavenger (see, for example, Patent Document 1).

JP 2000-9882 A

On the other hand, the radioactive iodine monitor that samples the air around the facility in an emergency has the same configuration as that continuously sampling. However, for emergency use, the pump has been in a standby state for a long time, so there is no air flow and the heater around the The humidity cannot be reduced, and the moisture-proofing effect on the iodine scavenger is not seen. Furthermore, between the inside of the airtight box in which the iodine scavenger is installed and the outside air, a change in temperature and a change in atmospheric pressure cause a breathing action and the iodine scavenger absorbs moisture. And since water is collected instead of iodine, there exists a problem that the collection efficiency of iodine and its compound falls.
Further, although it is technically possible to make the airtight box in which the iodine scavenger is installed a highly airtight structure, there is a problem that the cost is significantly increased.

  An object of the present invention is to provide a radioactive iodine sampler that maintains a low hygroscopicity of the iodine scavenger and prevents a reduction in the scavenging efficiency even when it has been in a standby state for a long period of time for emergency use, and a radioactive iodine sampler that can prevent a decrease in the scavenging efficiency. It is to provide a radioactive iodine monitor.

The radioactive iodine sampler according to the present invention samples the environmental air in order to detect radiation emitted from radioactive iodine contained in the environmental air, and uses the sampled iodine in the air or a compound thereof as an iodine scavenger. In the radioactive iodine sampler to be collected, during standby, an airtight storage means for storing the iodine collection agent in an airtight state, and a dehumidification means for dehumidifying water vapor from the air in the space in which the iodine collection agent is stored, provided, the dehumidifying means is a hygroscopic agent placed in the space, the iodine the sampled air when collecting the iodine or a compound of the sampled air in the iodine capturing agent and thereby discharged to the outside of the space leads to the collection agent to form a flow path that is isolated from the space surrounding the said gas-tight housing means, said yo A cartridge holder and the suction head sandwich the element scavenger from both sides, is provided with.

  The effect of the radioactive iodine sampler of the present invention is provided with a dehumidifying means for dehumidifying water vapor from the air in the space in which the standby iodine scavenger is accommodated in an airtight state. In addition, the iodine scavenger is always placed under low humidity conditions, and the trapping efficiency of the iodine scavenger that collects iodine and its compounds in an emergency can be maintained at a high level.

  The present invention can be applied to a radioactive iodine monitor and a radioactive iodine sampler. The radioactive iodine monitor here refers to a sampling unit that collects iodine and its compounds in an activated carbon cartridge, and radiation that is integrated with the sampling unit and detects radiation emitted from radioactive iodine collected in the activated carbon cartridge. And a detection unit. On the other hand, the radioactive iodine sampler is composed of a sampling unit that collects iodine and its compound in an activated carbon cartridge, and detects radiation emitted from the radioactive iodine collected in the activated carbon cartridge by a radiation detector. . Since this invention relates to the sampling part which collects iodine and its compound especially in an activated carbon cartridge, both are common and the following description mainly explains a radioactive iodine monitor.

Embodiment 1 FIG.
FIG. 1 is a block diagram of a radioactive iodine monitor according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the dehumidifier according to the first embodiment. In FIG. 1, the detector holder, packing, activated carbon cartridge, suction head, cartridge supply mechanism, and airtight box are shown as a longitudinal sectional view.
The radioactive iodine monitor of Embodiment 1 is installed in the station building 1 outside the nuclear power plant, for example. The radioactive iodine monitor is roughly divided into a sampling unit 2 that collects iodine and its compounds from the environmental air to be detected, a radiation detection unit 3 that detects radiation released from the collected radioactive iodine, and It is composed of

First, the sampling unit 2 includes a suction nozzle 4 that sucks in ambient air outside the station 1, a mist separator 5 that separates and collects mist contained in the sucked sample air, and a downstream as viewed from the suction nozzle 4. A check valve 6 that is opened when the pressure on the side decreases to a predetermined differential pressure or more compared to the upstream side, and a sample air heater 7 that heats the sample air when the sample air is sucked in. The pipes 8 are connected in series. The mist separator 5 is provided with a drain valve 9 for draining the accumulated mist during inspection. The check valve 6 is closed during standby and seals the downstream side. The sample air heater 7 heats the sample air to lower the relative humidity.
A pipe 8 connected to the downstream side from the sample air heater 7 extends through the seal member 10 into an airtight box 11 constituting the sampling unit 2.

  Further, the sampling unit 2 holds the radiation detector 12 and is also used as a cartridge holder. The detector holder 16 that supports the activated carbon cartridge 14 together with the suction head 15 located below and the electromagnetic solenoid 17 operate to operate vertically. The suction head 15 is pushed up in the direction, thereby pushing up the activated carbon cartridge 14, and the detector holder 16 and the suction head 15 are respectively disposed on the opposing sealing surfaces. When the activated carbon cartridge 14 is pushed up, the detector holder 16 and the suction head are arranged. 15 is composed of a packing 18 that isolates the internal space from the airtight box 11.

  Although not shown, the activated carbon cartridge 14 is a cartridge in which activated carbon as an iodine scavenger is filled in a cylindrical container, the container end surface is covered with a fiber sheet, and the fiber sheet is bonded and fixed to the container by a ring. Yes, it is commercially available and can be easily obtained.

The activated carbon cartridge 14 is supplied between the detector holder 16 and the suction head 15 by the cartridge supply mechanism 20 prior to the intake of the sample air.
The cartridge supply mechanism 20 is provided horizontally between the detector holder 16 and the suction head 15, and has a fixed plate 21 in which a hole is formed in a region where the suction head 15 is raised and lowered. A rotating plate 22 that is supported and has a hole that can accommodate a plurality of activated carbon cartridges 14 on the circumference, a motor 23 for rotating the rotating plate 22, and a gear 24 that transmits the rotation of the motor 23 to the rotating plate 22. ing.
The activated carbon cartridge 14 is in a state of being placed on the fixed plate 21 except for the portion above the suction head 15. Then, when the motor 23 is rotated and the gear 24 is rotated in conjunction with the rotation of the motor 23, the rotating plate 22 is rotated accordingly, the activated carbon cartridge 14 is slid and moved on the fixed plate 21, and the new activated carbon cartridge 14 is sucked. It is disposed on the head 15.

A flexible hose 26 for exhausting air from the suction head 15 is connected, and a pipe 8 passing through the seal member 10 is connected to the tip of the flexible hose 26, and the pipe 8 extends to the outside of the airtight box 11. Since the flexible hose 26 is connected to the suction head 15, the suction head 15 can be raised and lowered. The suction head 15 is moved up and down by an electromagnetic solenoid 17.
The sampling unit 2 is further connected to a pipe 8 extending from the suction head 15, connected to a flow meter 27 and a flow meter 27 for measuring the flow rate of air exhausted from the suction head 15, and discharges air from downstream. And an exhaust nozzle 29 through which air discharged from the pump 28 is discharged out of the station 1.

  Further, the sampling unit 2 controls the dehumidifier 31 as a dehumidifying means for dehumidifying the air in the airtight box 11 and the cartridge supply mechanism 20 so as to place the activated carbon cartridge 14 on the suction head 15 and raise and lower the suction head 15. The control unit 32 is configured to control the pump 28 based on the flow rate to intake and exhaust, and to control the sample air heater 7 to heat the sample air.

In the dehumidifier 31, as shown in FIG. 2, a hygroscopic agent 36 is placed in a storage bag 37, for example, a bag having good air permeability such as a hemp bag, and the storage bag 37 is provided with a storage case 38 having a number of holes. Is placed inside. The storage case 38 is fixed to the wall of the airtight box 11 by a mounting plate 39.
As the hygroscopic agent 36, silica gel, molecular sieve, zeolite, and the like are commercially available and can be easily obtained, and the amount used is determined according to the state of the seal portion and is periodically replaced.

  On the other hand, the radiation detector 3 detects radiation emitted from radioactive iodine held in the detector holder 16 and collected in the activated carbon cartridge 14 and converts the radiation into an electric pulse from the radiation detector 12 and the radiation detector 12. The measurement unit 34 is configured to discriminate the pulse height of the output electric pulse corresponding to the peak height spectrum peak of the radioactive iodine to be measured, and to output a count rate corresponding to the concentration of radioactive iodine.

  The radioactive iodine monitor further includes an interface unit 35 that transmits a control signal for controlling the sampling unit 2 from outside the station 1 and a count rate output from the measurement unit 34 to the outside of the station 1.

In the radioactive iodine monitor used in an emergency, the inside of the airtight box 11 is sealed by a standby check valve 6 and a check valve (not shown) in the pump 28. As described above, in the first embodiment, the airtight storage means for storing the iodine scavenger in an airtight state includes the check valve 6, the airtight box 11, and the check valve (not shown) in the pump 28.
On the other hand, in an emergency, the cartridge supply mechanism 20 is driven to place the activated carbon cartridge 14 on the suction head 15. Then, the suction head 15 is pushed up by the electromagnetic solenoid 17, and the detector holder 16, the activated carbon cartridge 14 and the suction head 15 are brought into close contact with each other, thereby constructing a flow path for the sample air. That is, the flow path of the sample air is exhausted downstream from the intake nozzle 4 via the mist separator 5, check valve 6, detector holder 16, activated carbon cartridge 14, suction head 15, flow meter 27, and pump 28. It reaches the nozzle 29. When the pump 28 is driven, a differential pressure is applied to the check valve 6, so the check valve 6 is opened, sample air is flowed to the activated carbon cartridge 14, and radioactive iodine in the sample air is collected in the activated carbon cartridge 14. The The radiation emitted from the radioactive iodine collected in this way is detected by the radiation detector 12. Radioiodine includes simple iodine and iodide such as methyl iodide.

The airtight box 11 contains the radiation detector 12, the detector holder 16, the activated carbon cartridge 14, the cartridge supply mechanism 20, the suction head 15, the electromagnetic solenoid 17, the packing 18, and the flexible hose 26, and keeps airtight against the outside air. ing. The detector may be placed in a sealed detector tube to keep it airtight.
The airtight box 11 is provided with an inspection window 33 for replacement of the activated carbon cartridge 14 and maintenance inside the airtight box 11. A portion where the pipe 8 or the wiring penetrates the hermetic box 11 and a joint portion are sealed by the seal member 10.
The station building 1 fixes the intake nozzle 4 and the exhaust nozzle 29 outside the station building 1 and stores and protects other devices inside.
The dehumidifier 31 can remove water vapor that enters the hermetic box 11 from a sealing portion during standby due to a breathing phenomenon caused by a change in temperature and pressure of outside air.

In such a radioactive iodine monitor, the air inside the airtight box 11 is dehumidified by the dehumidifier 31 during standby, so that the activated carbon cartridge 14 can always be maintained in a suitable state of low humidity.
Moreover, since the air inside the airtight box 11 is maintained at a low humidity, there is an effect of rust prevention for the inner surface of the airtight box 11 and the equipment accommodated therein.
In addition, when sampling air containing corrosive gas in a nuclear power generation facility or fuel cycle facility, the hygroscopic agent 36 adsorbs corrosive gas that leaks and diffuses into the airtight box 11, so that the inner surface of the airtight box 11 and the inside thereof. It has the effect of preventing corrosion of installed equipment.

The activated carbon cartridge 14 is filled with activated carbon as an adsorbent for iodine and its compounds, but an adsorbent having the same function and performance can be used.
Further, instead of the activated carbon cartridge 14, activated carbon fibers in a felt shape can be punched into the same plane shape and applied.

Embodiment 2. FIG.
FIG. 3 is a block diagram of a radioactive iodine monitor according to Embodiment 2 of the present invention. In FIG. 3, the detector holder, the packing, the activated carbon cartridge, the suction head, and the pressing mechanism are shown as a longitudinal sectional view.
Unlike the radioactive iodine monitor of the first embodiment, the radioactive iodine monitor of the second embodiment includes only one activated carbon cartridge 14. The activated carbon cartridge 14 is pushed up by the suction head 15 pushed up by the standby pressing mechanism 40 and is kept airtight with the detector holder 16. Thus, since one activated carbon cartridge 14 is kept airtight, the cartridge supply mechanism 20 and the airtight box 11 are omitted.
During standby, the spaces in the detector holder 16, the activated carbon cartridge 14, and the suction head 15 are hermetically sealed by the check valve 6 and a check valve (not shown) provided in the pump 28. In order to dehumidify the hermetically sealed space, a dehumidifying box 45 is provided at the end of the pipe 8 branched from the downstream side of the flexible hose 26, and the dehumidifying box 45 is similar to the first embodiment. A dehumidifier 31 is attached. As described above, the airtight housing means in the second embodiment includes the check valve 6, the detector holder 16, the packing 18, the suction head 15, the pressing mechanism 40, and the check valve (not shown) in the pump 28.

The pressing mechanism 40 is fixed to the movable shaft 41 that moves the suction head 15 up and down, the guide 42 that supports the movable shaft 41 so as to be linearly movable while rotating up and down, and is fixed to the lower end of the movable shaft 41 and rotates. The handle 43 is configured to move the movable shaft 41 up and down. When the handle 43 is manually rotated, the movable shaft 41 moves in the vertical direction along the guide 42 and pushes up the suction head 15.
As a result, the seal head 15 and the activated carbon cartridge 14, the detector holder 16, and the activated carbon cartridge 14 are brought into close contact with each other via the packing 18 to form a flow path for sample air. At the time of standby, it is waiting in this state. In an emergency, an activation signal of the pump 28 is inputted from the outside to the control unit 32 via the interface unit 35, sampling is started, an external stop signal, or a built-in signal (not shown) When a stop signal based on the timer is input from the control unit 32 to the pump, the pump 28 is stopped and sampling is completed.

  In the activated carbon cartridge 14 that has been collected, the radiation detector 12 detects the radiation emitted from the radioactive iodine. After the detection, the activated carbon cartridge 14 is removed by rotating the handle 43 in the reverse direction and lowering the movable shaft 41. Thereafter, the new activated carbon cartridge 14 is placed on the suction head 15, and then the handle 43 is rotated. By moving the movable shaft 41 upward, a new activated carbon cartridge 14 is mounted between the detector holder 16 and the suction head 15.

  Since such a radioactive iodine monitor only needs to dehumidify only the air in the detector holder 16, the suction head 15, and the activated carbon cartridge 14, even if a small dehumidifier is used, the activated carbon cartridge is always in a suitable state of low humidity. Can be maintained.

Embodiment 3 FIG.
FIG. 4 is a block diagram of a radioactive iodine sampler according to Embodiment 3 of the present invention. In FIG. 4, the cartridge presser, the activated carbon cartridge, the suction head, and the pressing mechanism are shown as a longitudinal sectional view.
In the radioactive iodine sampler of the third embodiment, the radiation detection unit 3 is omitted from the radioactive iodine monitor of the second embodiment, a plurality of a series of devices from the check valve 6 to the suction head 15 are provided, and a plurality of collection channels are provided. Is different from the radioactive iodine monitor of the second embodiment, and the others are the same. Therefore, the same reference numerals are given to the same parts, and the description is omitted. In addition, the check valve 6 to the electromagnetic valve 46 are labeled with only one collection flow path, but are omitted because they are the same in all three.
Further, in order to hold the activated carbon cartridge 14 from above, a cartridge holder 45 as a cartridge holder is provided instead of the detector holder 16 of the second embodiment.

As shown in FIG. 4, the radioactive iodine sampler of Embodiment 3 will be described with an example having three collection channels, but the number of collection channels is not limited to three. Absent.
In the radioactive iodine sampler, in order to select a plurality of collection channels, an electromagnetic valve 46 is provided at the tip of the flexible hose 26 connected to the downstream side of the suction head 15 included in each collection channel. The collection flow path is selected by opening and closing the electromagnetic valve 46, which is provided respectively. As described above, the airtight housing means in the third embodiment includes the check valve 6, the cartridge presser 45, the packing 18, the suction head 15, and the electromagnetic valve 46.
At the time of standby, all of the plurality of collection channels are in a state of being hermetically sealed by the check valve 6 and the electromagnetic valve 46. In an emergency, when an electromagnetic valve selection signal and an activation signal for the pump 28 are input from the outside to the control unit 32 via the interface unit 35, the selected electromagnetic valve 46 is opened and the pump 28 is activated. Then, sampling of air is started, and when a stop signal from the outside or a stop signal based on a built-in timer (not shown) is input from the control unit 32 to the pump, the pump 28 is stopped and the sampling is completed. Then, radioactive iodine can be collected while the solenoid valve 46 is sequentially switched by an external operation or a timer of the control unit 32.
The activated carbon cartridge 14 that has been collected is removed by operating the handle 43 and replaced with a new one. The activated carbon cartridge 14 that has been removed is measured for radiation emitted from radioactive iodine by a radiation detector installed at another location.

Since such a radioactive iodine sampler can collect radioactive iodine in a plurality of activated carbon cartridges by inputting a solenoid valve selection signal from the outside, it is possible to switch between a plurality of activated carbon cartridges even from a remote location in an emergency. Can be collected.
Note that the number of the activated carbon cartridge 14 may be one as in the second embodiment.

Embodiment 4 FIG.
FIG. 5 is a configuration diagram of a dehumidifier according to Embodiment 4 of the present invention.
The radioactive iodine monitor according to the fourth embodiment is the same as the first embodiment except for the dehumidifier 31b provided in the airtight box 11 of the radioactive iodine monitor according to the fourth embodiment. To do.
As shown in FIG. 5, the dehumidifier 31 b according to the fourth embodiment is disposed in the airtight box 11, disposed outside the airtight box 11, the cooling coil 51 through which the cooled refrigerant flows, and the input of the cooling coil 51. The cooling unit 52 that is connected to the output and cools the refrigerant and flows to the cooling coil 51, is disposed below the cooling coil 51, and is collected in the drain receiver 53 that receives the moisture condensed and dropped by the cooling coil 51. The drain discharge electromagnetic valve 54 is opened so as to periodically discharge the water out of the hermetic box 11, one end is connected to the drain discharge electromagnetic valve 54, and the other end passes through the wall of the hermetic box 11 outside the hermetic box 11. It is comprised from the drain pipe 55 extended. The drain discharge electromagnetic valve 54 is normally closed and is periodically operated by a control signal from the control unit 32. Note that a portion where the cooling coil 51 and the drain pipe 55 penetrate the wall of the hermetic box 11 is sealed by the seal member 10. Here, the drain discharge means includes a drain receiver 53, a drain discharge electromagnetic valve 54, and a drain pipe 55.
As the refrigerant, cooled water, alternative chlorofluorocarbon gas or the like can be used, and the cooling coil may be a heat pipe.
Such a dehumidifier 31b cools the air in the sealed system and condenses and removes the water vapor, so that no hygroscopic agent is required and the hygroscopic agent is not replaced, so that maintenance costs can be reduced.

Embodiment 5 FIG.
FIG. 6 is a perspective view of a dehumidifier according to Embodiment 5 of the present invention.
The radioactive iodine monitor according to the fifth embodiment is different only in the dehumidifier 31b according to the fourth embodiment, and the others are the same, and thus the description thereof is omitted.
The dehumidifier 31c of the fifth embodiment is different from the dehumidifier 31b of the fourth embodiment in the means for cooling the air inside the airtight box 11, and the others are the same.
As shown in FIG. 6, the means for cooling the air of the dehumidifier 31c according to the fifth embodiment is fitted into the through hole 11c provided in the wall 11b of the hermetic box 11 and fixed to the wall, and one surface is hermetically sealed. 11, a heat radiating plate 57 disposed so that the other surface faces the inside of the airtight box 11, a Peltier device 58 thermally adhered to a surface of the heat radiating plate 57 facing the inside of the airtight box 11, and a Peltier device The cooling fin 59 and the Peltier element 58 are configured to include a power source 60 for applying a DC voltage to the Peltier element 58. The liquid droplet condensed and dropped by the cooling fin 59 is received by the drain receiver 53.

In the Peltier element 58, a common electrode is attached to the cooling fin 59 via a ceramic substrate, and one side of an n-type semiconductor and a p-type semiconductor is attached to the common electrode. In addition, an individual electrode is attached to the heat radiating plate 57 via a ceramic substrate, and the other one side of the n-type semiconductor and the p-type semiconductor is attached to the individual electrode.
When a p-type semiconductor individual electrode is a positive electrode and an n-type semiconductor individual electrode is a negative electrode and a DC voltage is applied between both electrodes by a power source 60, electrons move from the common electrode toward the negative electrode. In the p-type semiconductor, holes move from the common electrode toward the positive electrode.
Along with this movement, movement of thermal energy occurs, and the common electrode side becomes in a state of energy shortage and is cooled as a result. By cooling the cooling fins 59, the air in the airtight box 11 is cooled, and the water vapor is condensed and removed. On the other hand, heating is performed on the individual electrode side, and the heat is transmitted to the heat radiating plate 57 and released to the outside air outside the airtight box 11.

  Since such a dehumidifier 31c is an electronic cooling system using the Peltier element 58, a refrigerator is not required unlike the refrigerant system, so that the apparatus becomes small.

Embodiment 6 FIG.
FIG. 7 is a sectional view of a dehumidifier according to Embodiment 6 of the present invention.
The dehumidifier 31d of the sixth embodiment is provided by being fitted into a through hole 11c provided in the wall 11b of the hermetic box 11. One side of the dehumidifier 31 d faces the outside A of the airtight box 11, and the other side faces the inside B of the airtight box 11.
As shown in FIG. 7, the dehumidifier 31 d includes a solid electrolyte membrane 61 that conducts protons, an anode 62 that is stacked on one side of the solid electrolyte membrane 61, and is disposed so as to face the inner side B of the hermetic box 11, The cathode 63 and the outer edge 61a of the solid electrolyte membrane 61, which are stacked on the other surface of the solid electrolyte membrane 61 and arranged to face the outer side A of the hermetic box 11, are supported and fixed to the wall 11b of the hermetic box 11. The mounting plate 64 includes a power source 60 that applies a DC voltage between the anode 62 and the cathode 63.
FIG. 8 is an enlarged view of the inside of the solid electrolyte membrane 61 according to the seventh embodiment. The solid electrolyte membrane 61 is a functional membrane having a thickness of about 200 μm as shown in FIG. 8A, and its function is to conduct hydrogen ions without passing gas or electrons as shown in FIG. 8B. It is to be. And this ion conduction function is exhibited when hydrogen ions are conducted along the sulfonyl group, as shown in FIG. As shown in FIG. 8D, the solid electrolyte membrane 61 has a structure having a fluorine-based resin in the main chain and a sulfonyl group SO ₃ ^— capable of adding a proton in the side chain. The solid electrolyte membrane 61 is, for example, a solid polymer electrolyte membrane, which is commercially available as DuPont's trade name Nafion (registered trademark), and is an electrically insulating transparent film that is harmless even if touched by hand. Easy to obtain. It should be noted that the voltage applied between the electrodes is as low as about 3 V, and it is safe even if electric leakage occurs.
The solid electrolyte membrane 61 is sandwiched between the anode 62 and the cathode 63. When a DC voltage of about 3 V is applied between the anode 62 and the cathode 63, hydrogen ions are absorbed along with the water absorbed by the anode 62. Move in.
The anode 62 and the cathode 63 are made of a material having a porous catalytic action. The anode 62 takes in water vapor and is ionized into oxygen ions and hydrogen ions by the catalytic action. It becomes oxygen gas on the surface and is released into the sample air, and hydrogen ions are conducted inside the solid electrolyte membrane 61 by an electric field, react with oxygen in the outside air on the surface of the cathode 63 to become water vapor, and are released together with the accompanying water vapor. Dehumidification of the airtight box 11 is performed.
The dehumidifying capacity D of the dehumidifier 31d using Nafion (registered trademark) is proportional to only the absolute humidity of the airtight box on the anode 62 side when the membrane area is constant, and is given by the equation (1).

D = 6 × 10 ² × p × S (1)

Here, D is the dehumidifying capacity (g / h) of the solid electrolyte membrane, p is the absolute humidity (g / cm ³ ) of the sample air, and S is the effective area (cm ² ) of the solid electrolyte membrane.

When the radioactive iodine monitor is operated for emergency use, it is normally in a standby state, and therefore it is sufficient that the area of the solid electrolyte membrane is about 100 mm × 100 mm.
In the case of constant use, sample air is diffused when the cartridge is switched, but the switching area is short, so a similar area is sufficient.
In a large radioactive iodine monitor with a large number of cartridges mounted, the required area can be obtained by equation (1).
As described above, since the water in the airtight box can be discharged to the outside through the solid electrolyte membrane, maintenance such as replacement of the hygroscopic agent becomes unnecessary, and the maintenance cost is reduced.
Moreover, since dew condensation water is not generated in the system in which the activated carbon is sealed, a drainage mechanism is unnecessary, and the equipment cost can be reduced.

Embodiment 7 FIG.
9 is a partial cross-sectional view of a suction head according to Embodiment 7 of the present invention.
The radioactive iodine monitor of the seventh embodiment is different in that the suction head heater 65 is added to the suction head 15 of the radioactive iodine monitor of the first embodiment, and the other parts are the same, so the description of the same parts is omitted. .
As shown in FIG. 9, the suction head heater 65 is disposed so as to be wound around the outer wall of the suction head 15. And since constant electric power is supplied to the suction head heater 65 from the control part 32, the suction head 15 is heated, heat is conducted from the suction head 15 to the activated carbon cartridge 14, and the activated carbon cartridge 14 is maintained at a suitable temperature. Is done. The suction head heater 65 suffices to raise the activated carbon cartridge 14 by about 10 ° C. from room temperature. Therefore, no special control is required and a constant capacity of power may be supplied. The suction head heater 65 may be operated during standby, but may be operated in conjunction with the operation of the pump 28.

By providing the suction head heater 65 in the suction head 15 as described above, even if the sample air heater 7 heats the sample air by maintaining the activated carbon stored in the activated carbon cartridge 14 at a suitable temperature. Since the heat capacity of air is small, it is possible to compensate for the temperature falling during the flow.
In addition, a heat insulating material for preventing burns by heating the sample air to a high temperature in anticipation of a temperature drop in the middle becomes unnecessary. Thus, by making activated carbon into suitable temperature, the collection efficiency of the iodine and its compound by activated carbon can be maintained highly efficient.

It is a block diagram of the radioactive iodine monitor concerning Embodiment 1 of this invention. 2 is a cross-sectional view of a dehumidifier according to Embodiment 1. FIG. It is a block diagram of the radioactive iodine monitor concerning Embodiment 2 of this invention. It is a block diagram of the radioactive iodine sampler concerning Embodiment 3 of this invention. It is a block diagram of the dehumidifier concerning Embodiment 4 of this invention. It is a perspective view of the dehumidifier concerning Embodiment 5 of this invention. It is sectional drawing of the dehumidifier concerning Embodiment 6 of this invention. FIG. 10 is a diagram for illustrating an internal state of a solid electrolyte membrane according to a sixth embodiment. It is a figure which shows the suction head concerning Embodiment 7 of this invention.

Explanation of symbols

  1 office building, 2 sampling section, 3 radiation detection section, 4 intake nozzle, 5 mist separator, 6 check valve, 7 sample air heater, 8 piping, 9 drain valve, 10 seal member, 11 airtight box, 12 radiation detection 14, activated carbon cartridge, 15 suction head, 16 detector holder, 17 electromagnetic solenoid, 18 packing, 20 cartridge supply mechanism, 21 fixed plate, 22 rotating plate, 23 motor, 24 gear, 26 flexible hose, 27 flow meter, 28 Pump, 29 Exhaust nozzle, 31, 31a to 31d Dehumidifier, 32 Control part, 33 Inspection window, 34 Measuring part, 35 Interface part, 36 Hygroscopic agent, 37 Storage bag, 38 Storage case, 39, 64 Mounting plate, 40 Press Mechanism, 41 Movable shaft, 42 Guide, 43 Hand , 45 Dehumidification box, 46 Solenoid valve, 51 Cooling coil, 52 Cooling unit, 54 Drain discharge solenoid valve, 55 Drain pipe, 57 Heat sink, 58 Peltier element, 59 Cooling fin, 60 Power supply, 61 Solid electrolyte membrane, 61a Outer edge 62 Anode, 63 Cathode, 65 Suction head heater.

Claims (2)

In order to detect the radiation emitted from radioactive iodine contained in the environmental air, in the radioactive iodine sampler that samples the environmental air and collects iodine in the sampled air or a compound thereof in an iodine scavenger,
An airtight storage means for storing the iodine scavenger in an airtight state during standby;
Dehumidifying means for dehumidifying water vapor from the air in the space in which the iodine scavenger is stored;
Is provided,
The dehumidifying means is a hygroscopic agent placed in the space,
When collecting iodine or its compound in the sampled air in the iodine scavenger, the sampled air is guided to the iodine scavenger and discharged out of the space, and the airtight housing means surrounds it. A radioactive iodine sampler comprising: a cartridge holder and a suction head that form a flow path isolated from a space and sandwich the iodine scavenger from both sides.   In the radioactive iodine monitor which detects the radiation discharge | released from the radioactive iodine collected by the said iodine collection agent, The radioactive iodine monitor provided with the radioactive iodine sampler of Claim 1 characterized by the above-mentioned.

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