JP5999473B2 - Collection unit, detector for radioactive gas monitor, and radioactive gas monitor - Google Patents

Description

  The present invention relates to a collection unit for collecting a radioactive substance from a radioactive gas containing a radioactive substance, a radioactive gas monitor detector for detecting radiation emitted from the radioactive substance collected in the collection unit, and the radioactive substance The present invention relates to a radioactive gas monitor that performs monitoring using a gas monitor detector.

  Nuclear power plants, spent nuclear fuel reprocessing facilities, hospitals, or inspection organizations are facilities where unsealed radioactive materials may be scattered in the air, and the radioactive materials are strictly controlled (hereinafter referred to as Simply called a management facility).

  The air in the management facility is sampled and monitored for the presence and concentration of radioactive materials. In addition, gas containing radioactive substances may be generated during various processes in the management facility, and a part of such gas is sampled, and the presence or concentration of the radioactive substance in the gas is monitored. Hereinafter, in the specification, these air and gas will be described as being radioactive gases.

  Next, a radioactive gas monitor that performs such monitoring will be described with reference to the drawings. This prior art is specifically an iodine gas monitor, in which the radioactive substance is radioactive iodine, and the radioactive gas is iodine gas. FIG. 11 is a configuration diagram of a main part of a conventional radioactive gas monitor. In the radioactive gas monitor 100, air in a management facility or gas generated in various processes is introduced from the gas inflow passage 101 as iodine gas. The iodine gas flows into the collecting cartridge 102 through the gas flow path. The collection cartridge 102 contains a collection agent therein. The collection agent has a function of collecting radioactive iodine present in iodine gas. When iodine gas passes through the collecting cartridge 102, radioactive iodine is collected. The iodine gas after the radioactive iodine is collected is discharged through the gas outflow passage 103. The radioactive iodine collected in the collection cartridge 102 emits γ rays and β rays. The periphery of the collection cartridge 102 is covered with a lead shield 104, and γ rays and β rays are exposed to the outside. It is made not to reach.

  A scintillator 105 is disposed on the upper side of the collecting cartridge 102. The scintillator 105 emits weak light in response to γ rays and β rays emitted from radioactive iodine. The light emitted from the scintillator 105 enters the photomultiplier tube 106. The photomultiplier tube 106 outputs a pulsed current signal corresponding to the light. The preamplifier 107 amplifies this pulsed current signal and converts it to a pulse signal based on voltage. This pulse signal is A / D converted and then input to the signal processing operation unit 108. The signal processing operation unit 108 estimates the energy of radiation from the magnitude of the pulse signal, discriminates the pulse signal which is γ-ray from radioactive iodine in particular, and counts the pulse signal to iodine gas. The radioactive iodine contained is counted and the concentration of radioactive iodine is calculated.

  In the radioactive gas monitor 100, the collection cartridge 102 is automatically replaced at regular intervals. This exchange function will be described. The collection cartridges 102 are stored in a state where a plurality of collection cartridges 102 are stacked in the collection cartridge storage unit 109. The lowermost collection cartridge 102 is placed on a transport unit 110 such as a belt conveyor. When the replacement time comes, the transport motor 112 operates the transport unit 110 in a state where the receiving unit 111 is lowered and the used collection cartridge 102 is movable. The new collection cartridge 102 placed on the conveyance unit 110 is conveyed on the upper side of the conveyance unit 110 and the used collection cartridge 102 is conveyed on the lower side of the conveyance unit 110. A new collection cartridge 102 is installed at a detection position below the scintillator 105. The used collection cartridge 102 conveyed below the conveyance unit 110 is put into the collection cartridge collection unit 113. Thereafter, the receiving portion 111 is raised and monitoring is possible. In such a radioactive gas monitor 100, monitoring is continuously performed over a long period of time.

  Further, as another conventional technique related to radiation detection, for example, an invention described in Patent Document 1 (Japanese Patent Laid-Open No. 8-285945, name of invention “radiation measurement device”) is known. The radiation measuring device described in Patent Document 1 is a device that uses a well-type scintillator that forms a hole in a scintillator, and detects radioactive substances contained in a sample (animal, food, soil, etc.) in a test tube. ing.

Japanese Patent Laid-Open No. 8-285945 (paragraph numbers [0018] to [0027], FIG. 1)

  The law stipulates that concentrations be calculated for radioactive materials in the exhaust at the outlet of the management facility and in the air at the boundary of the management facility, and that this concentration be less than the predetermined exhaust concentration limit. Yes. However, the radioactive gas monitor of the prior art cannot detect radiation when there are few radioactive substances contained in the radioactive gas and the concentration is low, that is, the detection lower limit concentration is high, and there is a problem that it cannot measure to the exhaust gas concentration limit. there were.

For example, when the radioactive gas monitor 100 described with reference to FIG. 11 monitors iodine, the detection lower limit concentration is about 10 ⁻³ Bq / cm ³ for I-129 and I-125. This is a large value of 500 to 1000 times the exhaust concentration limit. This is because the radionuclide concentration limit of the nuclide called iodine is set very low, and the iodine detection capability of the radioactive gas monitor 100 cannot catch up. At present, low concentrations below the detection limit concentration limit for radioactive iodine cannot be detected, and there is a fatal capability limit that it cannot be determined whether the concentration is below or below the exhaust concentration limit.

  Consider the reason. FIG. 12 is an explanatory diagram for explaining the arrival of the radiation radiated from the radioactive substance to the scintillator. If the radiation from the radioactive iodine A collected in the collection cartridge 102 is emitted within the oblique line, it reaches the scintillator 105 and is detected. Considering that radiation is radiated from the radioactive iodine A in a random direction, it cannot be detected because it does not reach the scintillator 105 when it is radiated out of the diagonal line, for example, in the lower direction of the collecting cartridge 102. Due to such low geometric counting efficiency, there is a problem that the detection lower limit concentration is high.

  In addition, the collection cartridge system communicates with the outside world for exchanging the collection cartridge, and there are many places where a lead shield cannot be installed, and it is difficult to completely shield it from the outside world. Therefore, the background enters the detection surface of the scintillator 105. Also by this, the detection signal from the radioactive iodine A is buried in the detection signal due to the background and cannot be detected. As a result, there is a problem that the detection lower limit concentration becomes high.

  Furthermore, when a collecting cartridge is used, iodine gas may pass through leaking around other than the collecting cartridge. In this case, there was also a problem that radioactive iodine could not be collected. This is a problem particularly when the concentration of radioactive iodine in iodine gas is low. In the conventional collecting cartridge, it is not easy to reliably pass iodine gas through the collecting agent.

  When such a prior art radioactive gas monitor monitored iodine, it could not detect radioactive iodine at the detection limit concentration limit level, so the outflow of radioactive iodine from the management facility was estimated from the usage amount. Has been done by the calculation. In calculation, since it is usually necessary to calculate with the safety factor taken into account, it may be different from the actual value.

  Therefore, there has been a request to be able to detect even a small amount of radiation at the exhaust gas concentration limit level. In order to increase the accuracy of evaluation that does not exceed the exhaust concentration limit, it is desirable that the detection lower limit concentration can be detected up to 1/10 or less of the exhaust concentration limit.

The present invention has been made in view of the above problems, and its purpose is to improve the collection capability by allowing the radioactive gas to pass through the adsorbent and collect the radioactive substance in a specific location. It is to provide the collected collection unit.
In addition, a detector for a radioactive gas monitor that has both improved geometric counting efficiency and reduced background when detecting radiation emitted from a specific location of this collection unit, and has greatly reduced the lower detection limit concentration. It is to provide.
It is another object of the present invention to provide a radioactive gas monitor that performs highly reliable monitoring using the detector for radioactive gas monitor.

In order to achieve the above object, the collection unit according to claim 1 is:
A container having a bottomed cylindrical shape and a storage space;
Disposed in the housing space, an adsorbent for adsorbing radioactive substances contained in the radioactive gas,
An adsorbent filling lid that is formed of a member through which a radioactive gas permeates and is arranged in the housing space and presses the adsorbent;
A sealing portion disposed in the housing space such that an intermediate space is formed between the adsorbent filling lid, and
A radioactive gas inlet passage opening is located near one end of the adsorbent to a bottom of the accommodating space,
And a gas outlet passage opening is located in the intermediate space a point away from the other end of the adsorbent be the accommodating space,
Wherein the intermediate space and between the negative pressure, the passes through the radioactive gas flowing from the opening of the radioactive gas inlet passage the adsorbent, radioactive materials adsorb radioactive gas the suction by the suction through the gas outlet channel The radioactive material is collected by passing through the agent filling lid and the intermediate space and flowing out from the opening of the gas outflow passage .

請 Motomeko radioactive gas monitor detector according to 2, and the collection unit according to claim 1,
A detection unit that is mounted with the collection unit to detect;
A detector for a radioactive gas monitor, comprising:
The detection unit is
A well-type scintillator that is installed so that the bottom of the container faces the bottom of the hole and converts radiation emitted from the radioactive material adsorbed by the adsorbent into scintillation light;
A shielding shield that shields the background, with a large outer periphery of the scintillator ,
Characterized Rukoto and an photomultiplier tube for converting a current signal amplifying scintillation light emitted from the scintillator.

Radioactive gas monitor detector according to 請 Motomeko 3, and the collection unit according to claim 1,
A detection unit that is mounted with the collection unit to detect;
A detector for a radioactive gas monitor, comprising:
The detection unit is
Bottom of the container of the collection unit to the bottom of the hole is placed so as to face an inner scintillator well type which converts the radiation emitted from the radioactive substance adsorbed before Ki吸 Chakuzai the scintillation light,
A well-type outer scintillator that is installed so that the bottom of the inner scintillator faces the bottom of the hole, and converts background from the outside into scintillation light different from the waveform of the inner scintillator;
And a photomultiplier tube that converts the scintillation light emitted from the inner scintillator and the outer scintillator into a current signal and amplifies the current signal .

Radioactive gas monitor detector according to 請 Motomeko 4 includes a container having a housing space a bottomed cylindrical shape, is disposed in the housing space, an adsorbent for adsorbing radioactive substances contained in the radioactive gas, the A radioactive gas inflow path having an opening located near one end of the adsorbent in the bottom of the accommodating space, and an opening in an intermediate space in the accommodating space and away from the other end of the adsorbent. A radioactive gas flowing in from the opening of the radioactive gas inflow passage passes through the adsorbent, and the radioactive gas adsorbed with the radioactive substance flows out of the opening of the gas outflow passage. A collection unit for collecting radioactive materials ;
A detection unit that is mounted with the collection unit to detect;
A detector for a radioactive gas monitor, comprising:
The detection unit is
Bottom of the container of the collection unit to the bottom of the hole is placed so as to face an inner scintillator well type which converts the radiation emitted from the radioactive substance adsorbed before Ki吸 Chakuzai the scintillation light,
Wherein and bottom of the inner scintillator is disposed so as to face the bottom of the hole, and the outer scintillator well type that converts the background from the outside before Symbol cie scintillation light different from the waveform of the inner scintillator,
Characterized in that it comprises a photomultiplier tube for converting amplified current signal scintillation light emitted from the inner scintillator and the outer scintillator.

Radioactive gas monitor according to 請 Motomeko 5 is the above radioactive gas monitor detector according to claim 2 or 3, wherein the radioactive gas supply unit is connected to the radioactive gas inlet passage, and the gas to the gas outlet channel A detector for a radioactive gas monitor in which the collection unit to which a discharge unit is connected is attached to the detection unit ;
A preamplifier for outputting the amplified voltage waveform signal by converting a current signal before Symbol photomultiplier tube voltage,
And the waveform discrimination operation section for outputting a radiation wave signals except the background discriminates a voltage waveform signal of the preamplifier,
And a signal processing operation unit that calculates a radioactivity concentration of a radioactive substance contained in the radioactive gas based on a radiation waveform signal from the waveform discrimination operation unit .

Radioactive gas monitor according to 請 Motomeko 6 is the radioactive gas monitor according to claim 5,
A collection unit storage section for storing a plurality of the collection units;
A transport section for transporting the collection unit from the collection unit storage section;
Communicates the before and Kiho morphism gas inlet path the radioactive gas supply unit, and a connecting portion connected to the collecting unit while communicating with the gas outflow passage and the gas discharge portion,
And a mounting portion to arrange the collecting unit to the detecting unit together with the connecting portion,
Monitoring is continuously performed by a plurality of the collecting units .

ADVANTAGE OF THE INVENTION According to this invention, the collection unit which improved the collection capability can be provided so that radioactive gas may pass an adsorbent reliably and a radioactive substance may be concentrated and collected in a specific location.
In addition, a detector for a radioactive gas monitor that has both improved geometric counting efficiency and reduced background when detecting radiation emitted from a specific location of this collection unit, and has greatly reduced the lower detection limit concentration. Can be provided.
Moreover, the radioactive gas monitor which performs highly reliable monitoring using this detector for radioactive gas monitors can be provided.

It is a block diagram of the collection unit which concerns on the form for implementing this invention. It is a block diagram of the detector for radioactive gas monitors which concerns on the form for implementing this invention. It is explanatory drawing explaining geometric counting efficiency. It is a block diagram of the detector for radioactive gas monitors which concerns on the other form for implementing this invention. FIG. 5A is a diagram illustrating a waveform of scintillation light, FIG. 5A is a diagram illustrating a waveform of an outer scintillator, and FIG. 5B is a diagram illustrating a waveform of an inner scintillator. It is a block diagram of the radioactive gas monitor which concerns on the form for implementing this invention. It is a block diagram of the radioactive gas monitor which concerns on the other form for implementing this invention. It is explanatory drawing of a radioactive gas monitor, FIG. 8 (a) is the sectional view on the AA line of a radioactive gas monitor, FIG.8 (b) is a top view of a part of radiation gas monitor. It is explanatory drawing of a radioactive gas monitor, Fig.9 (a) is a partial cross section figure which looked at the collection unit with a connection part with which the connection part was connected from the plane, FIG.9 (b) is a connection part with which the connection part was connected. It is the partial sectional view seen from the side of an attached collection unit. It is explanatory drawing about attachment / detachment with a connection part and the collection unit with a connection part, Fig.10 (a) is a figure which shows the fixed state of a connection part and the collection unit with a connection part, FIG.10 (b) is a connection part. FIG. 10C is a diagram showing the connecting operation between the connecting portion and the collecting unit with the connecting portion. It is a principal part block diagram of the radioactive gas monitor of a prior art. It is explanatory drawing explaining arrival of the radiation radiated | emitted from a radioactive substance to the scintillator.

  Then, the form for implementing this invention is demonstrated below, referring a figure. First, the collection unit will be described. FIG. 1 is a configuration diagram of the collection unit. In the present specification, for the purpose of concrete description, it will be described as an example of a radioactive gas of the present invention that is an elemental gas containing iodine in the air. Further, the description will be made assuming that the radioactive substance is radioactive iodine. Further, since iodine is removed from the radioactive gas that has passed through the adsorbent, it will be described as a simple gas.

  The collection unit 1 of this embodiment includes a container 11, a radioactive gas inflow passage 12, an adsorbent 13, an adsorbent filling lid 14, a sealing portion 15, an intermediate space 16, and a gas outflow passage 17.

  The container 11 is a bottomed cylinder type and has a storage space. For example, as shown in FIG. 1, the accommodation space has the same shape as the inside of the test tube, and the tip has a spherical shape. The material of the container 11 is a member that transmits radiation from a radioactive substance and has sufficient strength. In this embodiment, it is a substance that transmits gamma rays of radioactive iodine, and is formed of a synthetic resin, a thin metal such as aluminum, or glass.

  The radioactive gas inflow path 12 is inserted to the bottom of the filled adsorbent 13, and one opening 12 a is near the bottom 11 a (end) at the end of the container 11, that is, at the end of the adsorbent 13. Located at the bottom (end). The other opening is connected to a radioactive gas supply unit that supplies the radioactive gas. In addition, this radioactive gas supply part is a pipe | tube which flows in the air in a management facility as iodine gas, or the pipe | tube which flows in the gas in the middle of a process as iodine gas. The iodine gas passes through the radioactive gas inflow passage 12 as indicated by an arrow a, and the iodine gas released from the opening 12 a flows into the adsorbent 13. Although FIG. 1 shows that the adsorbent 13 does not exist below the opening 12a, even if there is some adsorbent 13 below the opening 12a, it flows into the adsorbent 13, so that It is good also as a position. The opening 12a may be near the bottom 11a.

The adsorbent 13 has a function of adsorbing radioactive iodine contained in iodine gas, and is, for example, activated carbon or impregnated coal. The impregnated charcoal uses triethylenediamine (TEDA), tin iodide (SnI ₂ ), or the like that can efficiently collect iodine at a low temperature as an adjunct adhering to the activated carbon. Activated carbon and impregnated coal are easily and inexpensively available. The iodine gas flows from the lower side to the upper side of the adsorbent 13 as indicated by an arrow b. The adsorbent 13 is filled with an appropriate amount so that all of the radioactive iodine contained in the iodine gas flowing in from the radioactive gas inflow passage 12 is absorbed. The amount will also take into account the operational environment, such as changes.

  The adsorbent filling lid 14 is disposed on the upper side of the adsorbent 13 and has a function of holding the adsorbent 13 so as not to move or dissipate. The adsorbent filling lid 14 is formed of a member through which iodine gas permeates, and is, for example, a sponge body. The adsorbent filling lid 14 allows the gas that has passed through the adsorbent 13 to have adsorbed all the radioactive iodine to pass therethrough.

  The sealing portion 15 is disposed on the upper side at a distance from the adsorbent filling lid 14. It is firmly fixed by a member that can withstand fluctuations in gas pressure.

  The intermediate space 16 is a space formed between the adsorbent filling lid 14 and the sealing portion 15. The gas that has passed through the adsorbent filling lid 14 passes through the intermediate space 16.

In the gas outflow path 17, one opening 17 a is disposed in the intermediate space 16 and communicates with the intermediate space 16. The other opening is connected to the gas discharge part. The gas discharge unit is, for example, an exhaust pump. When the exhaust pump is operated, the gas in the intermediate space 16 is exhausted, and the intermediate space 16 is formed at a negative pressure, so that iodine gas is sucked from the lower adsorbent 13 through the adsorbent filling lid 14. The
The configuration of the collection unit 1 is such.

  Then, the collection principle of the collection unit 1 of this form is demonstrated. When the exhaust pump, which is a gas discharge unit, operates, the gas in the intermediate space 16 is exhausted via the gas outflow path 17. Then, the atmospheric pressure in the accommodation space below the adsorbent filling lid 14 and filled with the adsorbent 13 is lowered. Then, iodine gas flows into the adsorbent 13 through the radioactive gas inflow passage 12. Since iodine gas flows in from the opening 12 a of the radioactive gas inflow path 12, it flows from the lower side to the upper side of the adsorbent 13 and passes through the adsorbent filling lid 14 and the intermediate space 16.

Here, the opening 12a of the radioactive gas inflow passage 12 and the opening 17a of the gas outflow passage 17 are
Since the adsorbent 13 is located at both ends, the iodine gas surely flows from end to end of the adsorbent 13, and as a result, the radioactive iodine in the element gas is left to flow through the adsorbent 13. It is devised to be absorbed by the adsorbent 13 instead. Further, the radioactive gas inflow passage 12 is located in the center of the accommodation space when viewed in cross section, and is located so that the adsorbent 13 surrounds the entire outer periphery in the vicinity of the opening 12a. Surely flows. Further, since the container 11 does not allow the iodine gas to pass through, the iodine gas does not leak.

  By such a flow of iodine gas, the adsorbent 13 reliably adsorbs the radioactive iodine contained in the iodine gas. At this time, more radioactive iodine is adsorbed in the tip region 13 a including the hemispherical tip below the adsorbent 13, and the adsorption of radioactive iodine decreases as it goes upward, and passes through the adsorbent filling lid 14. By the time, all radioactive iodine is adsorbed. The collection unit 1 of the present invention is like this.

The collection unit 1 of the present invention has been described above. In this collection unit 1, in particular, the adsorbent 13 is disposed in the accommodating space of the container 11 that is a closed space, and the iodine gas passes through the adsorbent 13 in the accommodating space without leaking. The radioactive iodine in iodine gas is adsorbed reliably.
Further, radioactive iodine is concentrated and collected in the adsorbent 13 in the accommodation space of the container 11, particularly the specific region called the tip region 13 a, and if γ rays are detected around the tip region 13 a. Devised to ensure reliable detection.

In addition, it has been demonstrated that the adsorbent 13 of the present invention exhibits sufficient capability at a flow rate of 3 L / min at the maximum. When the diameter of the opening in the container is 20 mm, the surface velocity with respect to the adsorbent is 0.96 L / cm ² .

On the other hand, the internal diameter of the cartridge 102 for collecting carbon by activated carbon used in the conventional iodine monitor is 50 mm, and the surface speed when operated at a flow rate of 50 L / min is 2.6 L / cm ² . In general, the life of the adsorbent 13 basically depends on the volume of elementary gas that has passed through the adsorbent 13. The recommended replacement time of the collecting cartridge 102 with the activated carbon collecting agent of the prior art is 8 hours. When compared with the surface velocity of iodine gas, it can be seen that the present invention can be used for about three times 24 hours.

  In addition, since the iodine collection life of the collection agent by activated carbon becomes longer as the surface velocity of iodine gas decreases, the collection unit 1 can actually be used for one day or longer. The low replacement frequency of the collection unit 1 indicates that the economic effect is high when used as a gas monitor.

  In addition, this collection unit 1 may be used for radioactive gas other than iodine gas, and the radioactive substance in this radioactive gas is adsorb | sucked reliably.

  These points are features that are not found in the collecting cartridge that covers the collecting agent of the prior art with a fibrous body, and the collecting unit 1 has greatly improved the collecting ability.

Next, a radioactive gas monitor detector according to an embodiment for carrying out the present invention will be described below with reference to the drawings. FIG. 2 is a configuration diagram of the detector for the radioactive gas monitor of the present embodiment.
The detector for radioactive gas monitor 2 of this embodiment includes a collection unit 1 and a detection unit 20. The detection unit 20 includes a scintillator 21, a photomultiplier tube 22, and a shielding shield 23. In addition, about the collection unit 1, it is the collection unit 1 demonstrated previously using FIG. 1, and while attaching | subjecting the same code | symbol, the overlapping description is abbreviate | omitted.

  The scintillator 21 is, for example, a thallium activated sodium iodide scintillation detector. The scintillator 21 detects γ rays emitted from radioactive iodine adsorbed and held by the adsorbent 13 of the collection unit 1. The activated carbon / iodinated charcoal that is the adsorbent 13 absorbs β rays, so that transmissive γ rays are incident on the scintillator 21. The scintillator 21 has a hole 21a and is installed so that the bottom 11a of the container 11 faces the bottom 21b of the hole 21a. This scintillator 21 is formed with a hole 21a like a well (well) and is called a well-type scintillator because radiation from a radioactive substance is detected in the hole 21a. The hole 21a of the scintillator 21 has such a shape that the container 11 of the collection unit 1 forms a slight gap, and is, for example, a hole having a circular cross section. The scintillator 21 also has a cylindrical outer shape.

  On the surface of the scintillator 21, a reflective layer that transmits γ rays but does not transmit scintillation light is formed. Note that the reflective layer is not formed on the surface in contact with the photomultiplier tube 22. The scintillation light emitted in the well-type scintillator 21 is irradiated to the photomultiplier tube 22 while being repeatedly reflected inside.

  A photomultiplier tube (PMT, photomultiplier) 22 generates electrons (photoelectrons) when the scintillation light is incident, amplifies the electrons, and outputs them as a pulsed current signal. In the photomultiplier tube 22, high voltage power is supplied from a high voltage power source (not shown) to amplify electrons.

The shielding shield 23 shields the background caused by gamma rays from the outside. The shield shield 23 is made of lead, for example, and reliably covers the outer periphery of the scintillator 21 and the photomultiplier tube 22. The hole of the shielding shield 23 has such a shape that the scintillator 21 forms a slight gap, and is, for example, a hole having a circular cross section. The outer shape of the shielding shield 23 is also formed in a cylindrical shape, for example. The shielding shield 23 shields the outside of the scintillator 21 in FIG. 2. However, for example, the shielding shield 23 may be elongated vertically so as to reliably cover the collection unit 1 and the photomultiplier tube 22. good. Even if the shielding shield 23 is long, the collection unit 1 can be easily replaced.
The detector 2 for radioactive gas monitor is like this.

  Next, detection of radiation by the radioactive gas monitor detector 2 of this embodiment will be described. When the exhaust pump, which is a gas discharge unit, operates, iodine gas flows into the adsorbent 13 of the collection unit 1 and radioactive iodine is collected. As described above, radioactive iodine in iodine gas is first adsorbed in a large amount with respect to the inflow path of the adsorbent 13, and thereafter the adsorption amount decreases exponentially.

  Therefore, by introducing iodine gas from the lower part of the adsorbent 13, a large amount of radioactive iodine is collected in the vicinity of the bottom 11a of the container 11 (the tip region 13a in FIG. 1). The tip 11 a of the container 11 is in contact with the bottom 21 b of the well-type scintillator 21. The γ-rays emitted from many radioactive iodines near the bottom 11a of the container 11 (the tip region 13a in FIG. 1) are adsorbents among the radiations emitted from the radioactive iodine A as shown in FIG. The radiation that passes through the hatched region 24 toward the filling lid 14 does not reach the scintillator 21, but the other radiation radiated downward or laterally reliably enters the scintillator 21 efficiently. Thus, the radiation is incident in almost all directions (excluding the opening at the top of the container 11), and the geometric counting efficiency is high. The radiation reaching the scintillator 21 increases by narrowing the opening of the container 11 and increasing the length of the container 11. Such a detector for radioactive gas monitor 2 can emit scintillation light efficiently. The detector 2 for a radioactive gas monitor of the present invention is as described above.

  The radio gas monitor detector 2 of the present invention has been described above. In this radioactive gas monitor detector 2, since the well-type scintillator 21 is disposed so as to cover the periphery of the radioactive iodine that is adsorbed more concentrated in the vicinity of the tip region 13 a of the adsorbent 13 in particular. Significantly increase the counting efficiency. This geometric counting efficiency becomes higher toward the bottom of the adsorbent 13. In the present invention, more radioactive iodine is intensively adsorbed in the vicinity of the tip region 13a of the adsorbent 13, and this is the reason for increasing the geometric counting efficiency.

11 and 12, the scintillator 105 is disposed in the vicinity of the collection cartridge 102. However, among the radiation emitted from the radioactive material in the collection cartridge 102, the scintillator 105 is The probability of incidence is 50% at the maximum, and the normal probability is 20-30% when the shape of the collection agent in the collection cartridge 102 is taken into consideration.
On the other hand, the radioactive gas monitor detector 2 of the present invention has a probability of entering the well-type scintillator 21 of 90% or more of the radiation emitted from the radioactive material in the adsorbent 13, and the geometric counting efficiency is Compared with the conventional one, it is 3 to 5 times better.

Further, the influence of the background is largely eliminated by the shielding shield 23, and the detection capability is also enhanced in this respect.
The detector 2 for monitoring a radioactive gas may be used for a radioactive gas other than iodine gas, and the radioactive substance in the radioactive gas is reliably adsorbed.

  In such a detector 2 for a radioactive gas monitor, radiation is radiated from a specific location of the collection unit 1 and the radiation is detected while the specific location is covered with a well-type scintillator 21. In addition, by covering the scintillator 21 with the shielding shield 23, both the improvement of the geometric counting efficiency and the reduction of the background are realized, and a detector for a radioactive gas monitor with a greatly reduced detection lower limit concentration can be provided. .

  Next, a radioactive gas monitor detector 3 according to another embodiment for carrying out the present invention will be described below with reference to the drawings. FIG. 4 is a configuration diagram of a detector for another form of radioactive gas monitor.

The detector for radioactive gas monitor 3 of this embodiment includes a collection unit 1 and a detection unit 30. The detection unit 30 includes an inner scintillator 31, an outer scintillator 32, and a photomultiplier tube 33. In addition, about the collection unit 1, it is the collection unit 1 demonstrated previously using FIG. 1, and while attaching | subjecting the same code | symbol, the overlapping description is abbreviate | omitted.
This embodiment is different from the detection unit 20 described above with reference to FIGS. 2 and 3 in that an inner scintillator 31 and an outer scintillator 32 are arranged instead of the scintillator 21. The photomultiplier tube 33 having the same configuration and function will be described with emphasis on this difference, and the same name as that of the photomultiplier tube 23 will be given, and redundant description will be omitted.

  The inner scintillator 31 is, for example, a thallium activated sodium iodide scintillation detector. The inner scintillator 31 detects γ rays emitted from radioactive iodine adsorbed and held by the adsorbent 13 of the collection unit 1. The activated carbon / iodinated charcoal that is the adsorbent 13 absorbs β rays, and γ rays having good permeability are incident on the inner scintillator 31. Further, the thickness of the inner scintillator 31 is set so that the γ rays do not reach the outer scintillator 32 beyond the inner scintillator 31. The inner scintillator 31 has a hole 31a, and is installed so that the bottom 11a of the container 11 faces the bottom 31b of the hole 31a. The inner scintillator 31 is a well-type scintillator in which holes such as wells are formed. The hole 31a of the inner scintillator 31 has such a shape that the container 11 of the collection unit 1 forms a slight gap, and is, for example, a hole having a circular cross section. The inner scintillator 31 also has a cylindrical outer shape.

  On the surface of the inner scintillator 31, a reflective layer that transmits γ rays but does not transmit scintillation light is formed. The reflective layer is not formed on the surface in contact with the bottom 32b of the hole 32a of the outer scintillator 32. The scintillation light emitted in the well-type inner scintillator 31 is incident on the photomultiplier tube 33 through the bottom 32b of the outer scintillator 32 while being repeatedly reflected inside.

  The outer scintillator 32 is, for example, a plastic scintillation detector. The outer scintillator 32 detects the background caused by γ rays from the outside. Further, the thickness of the outer scintillator 32 is set so that the γ rays do not reach the inner scintillator 31 beyond the outer scintillator 32. The outer scintillator 32 has a hole 32a, and is installed so that the bottom 31b of the inner scintillator 31 faces the bottom 32b of the hole 32a. This outer scintillator 32 is also a well-type scintillator in which holes such as wells are formed. The hole 32a of the outer scintillator 32 has such a shape that the inner scintillator 31 forms a slight gap, and is, for example, a hole having a circular cross section. The outer scintillator 32 also has a cylindrical outer shape.

  A reflection layer that transmits radiation but does not transmit scintillation light is formed on the surface of the outer scintillator 32. The reflective layer is not formed on the surface in contact with the photomultiplier tube 33 and the bottom 31 b of the inner scintillator 31. The scintillation light emitted in the well-type outer scintillator 32 enters the photomultiplier tube 33 while being repeatedly reflected inside.

  Subsequently, detection of radiation by the radioactive gas monitor detector 3 of the present embodiment will be described. When the exhaust pump, which is a gas discharge unit, is operated, iodine gas flows into the adsorbent 13 of the collection unit 1 and radioactive iodine is collected. As described above, it is known that radioactive iodine in iodine gas is first adsorbed in a large amount with respect to the inflow path of the adsorbent 13, and thereafter the adsorption amount decreases exponentially.

  Therefore, by introducing iodine gas from the lower part of the adsorbent 13, a large amount of radioactive iodine is collected in the vicinity of the bottom 11a of the container 11 (the tip region 13a in FIG. 1). The tip 11 a of the container 11 is in contact with the bottom 31 a of the well-type inner scintillator 31. The γ-rays emitted from many radioactive iodines near the bottom 11a of the container 11 (the tip region 13a in FIG. 1) are adsorbents among the radiations emitted from the radioactive iodine A as shown in FIG. The radiation passing through the hatched area 24 toward the filling lid 14 does not reach the inner scintillator 31, but other radiation radiated downward or laterally reliably enters the inner scintillator 31 efficiently. Thus, the radiation is incident in all directions (except for the opening at the top of the container 11). Radiation reaching the inner scintillator 31 increases by narrowing the opening of the container 11 and increasing the length of the container 11. Such a detector for radioactive gas monitor 3 can emit scintillation light efficiently.

  On the other hand, the outer scintillator 32 generates scintillation light corresponding to the background incident from the outside.

  However, the inner scintillator 31 and the outer scintillator 32 are set so that the rise time and the fall time of scintillation light emission are different. For example, the scintillation light waveform in the inner scintillator 31 has a steep pulse waveform as shown in FIG. 5B, and the scintillation light waveform in the outer scintillator 32 has a gentle pulse as shown in FIG. 5A. It becomes a waveform. Accordingly, scintillation lights having different emission waveforms from the inner scintillator 31 and the outer scintillator 32 are received by one photomultiplier tube 33, converted into current signals having different waveforms, and output. However, if the waveform discrimination processing is performed, only a steep waveform current signal from the inner scintillator 31 can be extracted, and the background can be removed.

  Further, in the arrangement of the scintillator 105 and the collection cartridge 102 of the conventional radioactive gas monitor 100 shown in FIGS. 11 and 12, the structure enters the scintillator 105 by entering from the lower side of the collection cartridge 102 upward. However, according to the present invention, the outer scintillator 32 prevents the background from reaching the inner scintillator 31, and converts the background into an identifiable signal. The ground can be removed by wave height discrimination. This makes it possible to greatly reduce the influence of the background, and as a result, the detection lower limit concentration can be lowered.

  In this embodiment, a cylindrical lead shield shield may be disposed outside the outer scintillator 32 to further reduce the influence of the background. The detector 3 for a radioactive gas monitor of the present invention is as described above.

  The radioactive gas monitor detector 3 of the present invention has been described above. Even in the detector 3 for the radioactive gas monitor, radiation is radiated from a specific location of the collection unit 1 and the radiation is detected while covering the specific location with a well-type inner scintillator and an outer scintillator. Especially, the background can be discriminated and removed, and both the improvement of the geometric counting efficiency and the reduction of the background are realized, and a detector for a radioactive gas monitor with a greatly reduced detection lower limit concentration can be provided. .

  Next, the radioactive gas monitor 4 of the present invention will be described with reference to the drawings. FIG. 6 is a configuration diagram of the radioactive gas monitor according to the present embodiment. This is a radioactive gas monitor 4 using the radioactive gas monitor detector 3 described above with reference to FIGS. 4 and 5. The radioactive gas monitor 4 includes the radioactive gas monitor detector 3, the preamplifier 41, the waveform discrimination calculation unit 42, the signal processing calculation unit 43, the output device 44, the radioactive gas inflow pipe 45 (radio gas supply) described with reference to FIGS. And an exhaust pump 46 (a specific example of the gas discharge unit).

  The preamplifier 41 amplifies a pulsed current signal corresponding to the light output from the photomultiplier tube 33 and performs I / V conversion to a voltage waveform signal by voltage.

  The waveform discrimination calculation unit 42 determines whether the signal is detected by the inner scintillator 31 or the signal detected by the outer scintillator 32 from the rise time and the fall time of the voltage waveform signal based on the voltage, and the inner scintillator 31. Only the voltage waveform signal based on the detection of the signal is extracted and output as a new radiation waveform signal to the signal processing calculation unit 43, and the voltage waveform signal detected by the outer scintillator 32 is discarded.

  The signal processing calculation unit 43 performs A / D conversion on the discriminated radiation waveform signal and inputs it. The signal processing operation unit 43 estimates the radiation energy from the peak spectrum peak of the radiation waveform signal, thereby discriminating the radiation waveform signal that is γ-ray from radioactive iodine in particular, and counting the radiation waveform signal. The radiation from the radioactive iodine contained in the iodine gas is counted, and the concentration of the radioactive substance is calculated based on this count.

  The output device 44 is, for example, a display device, and displays the concentration of the radioactive substance or various values calculated using this concentration (for example, values (concentrations) for each nuclide) in an emergency such as an accident. Enable measurement.

  The radioactive gas inflow pipe 45 is a specific example of the radioactive gas supply unit, and is, for example, a pipe that communicates with the space in the management facility. The radioactive gas inflow pipe 45 is connected to the radioactive gas inflow passage 12 of the collection unit 1.

  The exhaust pump 46 is a specific example of the gas discharge unit, and allows iodine gas to pass through the collection unit 1 by exhaust. The exhaust pump 46 is connected to the gas outflow path 17 of the collection unit 1.

  Subsequently, monitoring by the radioactive gas monitor 4 will be described. The radioactive gas monitor 4 samples the air in the management facility as iodine gas. When the exhaust pump 46 serving as a gas discharge unit exhausts the intermediate space 16, iodine gas passes through the collection unit 1 and collects radioactive iodine. In particular, most of the radioactive iodine is collected in the tip region 13a.

  In the detection unit 30, the inner scintillator 31 and the outer scintillator 32 emit scintillation light, and the photomultiplier tube 33 outputs a current signal corresponding to the scintillation light. The preamplifier 41 converts this current signal into a voltage and amplifies it to convert it into a voltage waveform signal. This voltage waveform signal is A / D converted and input to the waveform discrimination calculation unit 42. The waveform discrimination calculation unit 42 outputs a radiation waveform signal obtained by extracting only the signal detected by the inner scintillator 32 from the rise time and the fall time of the voltage waveform signal to the signal processing calculation unit 43. The signal processing calculation unit 43 estimates the radiation energy from the peak height peak of the radiation waveform signal, thereby discriminating the radiation waveform signal that is γ-ray from radioactive iodine in particular, and counting the radiation waveform signal. The concentration of radioactive iodine is detected from the number of radioactive iodine contained in the elementary gas. Then, the output device 44 outputs the concentration or various values calculated using the concentration (for example, a value (concentration) for each nuclide). Monitoring would be something like this.

Next, the performance of the radioactive gas monitor 4 according to the present invention will be described.
Radioactive iodine was adsorbed to the adsorbent 13 from gaseous iodine gas, and the detection lower limit concentration was measured. With respect to I-125, in the case of 1 l / min, it was possible to measure to 1/10 or less of the air concentration limit in 2 minutes and to 1/10 or less of the exhaust gas concentration limit in 60 minutes. For I-129, by calculation, at 1 l / min, the measurement time is 5 minutes and less than 1/10 of the air concentration limit, and at a flow rate of 3 l / min, the exhaust concentration limit is 10 minutes at 130 minutes. It was confirmed that it was possible to measure up to 1 or less. The radioactive gas monitor 4 of the present invention is such.

  The radioactive gas monitor 4 of the present invention can measure up to 1/10 of the concentration limit in real time, and can measure the concentration with sufficient accuracy even near the detection lower limit concentration. As a result, the safety of the work environment can be secured, and data useful for the safety of the surrounding environment can be provided, which is extremely effective for radiation management.

  In this embodiment, the radioactive gas monitor detector 3 is used as a detector. However, the radioactive gas monitor detector 2 described with reference to FIGS. 2 and 3 may be used. Waveform discrimination is possible when the input background also has different waveforms due to differences in energy. Such a configuration may be adopted.

  The radioactive gas monitor 4 of the present invention has been described above. In this radioactive gas monitor 4, the detection for the radioactive gas monitor has been achieved, in particular, by improving both the geometric counting efficiency of radiation radiated from a specific part of the collection unit 1 and reducing the background, and greatly reducing the lower detection limit concentration. By using the device, it is possible to provide a radioactive gas monitor that performs highly reliable monitoring. Further, by displaying the concentration of the radioactive substance or various values calculated using this concentration (for example, the value (concentration) for each nuclide), it is possible to measure in an emergency such as an accident.

  Next, the radioactive gas monitor 5 of the present invention will be described with reference to the drawings. 7 to 10 are configuration diagrams of a radioactive gas monitor according to another embodiment. In particular, this radioactive gas monitor 5 automatically connects the collection unit, attaches the collection unit to the detection unit, supplies the collection unit before use, and automatically collects the used collection unit. The radioactive gas monitor 5 is provided with an exchange function and enables continuous operation.

  In the radioactive gas monitor 5 of this embodiment, as shown in FIGS. 7, 8A, and 8B, the collection unit 6 with connection part, the collection unit storage part 51 with connection part, the transport part 52, and with the connection part A collection unit collection unit 53, a coupling unit 54, a shaft 55, a mounting unit 56, a rotating shaft 57, and a conveyance motor 58 are provided.

  The collecting unit 6 with connection part is the one to which the configuration of the collecting unit 1 is added especially for automatic replacement. Specifically, as shown in FIGS. 7, 8, 9, and 10, the collecting unit 1. A connecting portion 61 is provided, and these are treated as an integral structure. The collection unit 1 of the collection unit 6 with a connection part is the same as what was demonstrated referring FIG. At the open end of the collection unit 1, as shown in FIGS. 9 and 10A, the connecting portion 61 is firmly fixed. The connecting portion 61 has a cubic connecting portion main body 611, and inside this connecting portion main body 611, a gas communicating with the radioactive gas inflow passage 612 and the gas outflow passage 17 communicating with the radioactive gas inflow passage 12 of the collection unit 1. Outflow passages 613 are formed, and openings 612a and 613a are opened, respectively. A square magnetic body 614 is fixed.

  Sealing bodies are provided around the openings 612a and 613a, and are connected in a state where the end face of the connecting portion 61 and the end face of the connecting portion 54 are in close contact with each other as shown in FIGS. 9 (b) and 10 (a). Then, the radioactive gas inflow path 542 and the radioactive gas inflow path 612 communicate with each other in a state sealed by the seal, and the gas outflow path 543 and the gas outflow path 613 communicate with each other so that a flow path is formed. It has become. Also, the magnetic body 614 is positioned by being fitted into the square hole.

Subsequently, the entire apparatus will be described.
As shown in FIG. 7, the collection unit storage part 51 with a connection part accommodates the collection unit 6 with a several connection part in the laminated | stacked state. In addition, although it was set as the structure laminated | stacked to an up-down direction, for example, it is good also as a structure which arranges horizontally and stores. The details of the collection unit storage unit 51 with the connection part are appropriately selected.

  The conveyance part 52 conveys the collection unit 6 with a connection part supplied from the collection unit storage part 51 with a connection part. For example, a belt conveyor.

  The collection unit with connection part collection unit 53 is a container that collects the used collection unit with connection part 6 through which iodine gas has passed and the radioactive iodine has been collected over a predetermined period. In addition, although it was set as the structure laminated | stacked to an up-down direction, it is good also as a structure which arranges and collects horizontally, for example. The details of the collection unit collection unit 53 with a connection unit are appropriately selected.

  The connection portion 54 is configured to be connected to the connection portion 61 of the collection unit 6 with a connection portion. Further, as shown in FIG. 10, the connection portion main body 541, the radioactive gas inflow passage 542, and the gas outflow passage. 543, an electromagnet 544, an inner spring 545, an outer spring 546, a shaft support portion 547, a connector 548 (see FIG. 9B), and a tube 549.

  As shown in FIG. 10A, the connecting portion main body 541 is a cubic member, and a radioactive gas inflow passage 542 and a gas outflow passage 543 are formed in the connecting portion main body 541. When the connection portion 54 and the connection portion 61 are connected, the radioactive gas inflow passage 542 communicates with the radioactive gas inflow passage 612 of the connection portion 61, and the gas outflow passage 543 communicates with the gas outflow passage 613 of the connection portion 61. A tube 549 is connected to the upper side of the radioactive gas inflow path 542 and the gas outflow path 543 through a connector 548 as shown in FIG. 9B, and the radioactive gas supply unit and the gas discharge are connected through these tubes 549. It will be connected with the part.

  As shown in FIG. 10A, the electromagnet 544 is urged in the direction of the arrow d by the inner spring 545 with respect to the connecting portion main body 541, and an outer spring 546 is inserted into the iron core 544a. Presses the magnetic body 614. A shaft support portion 547 that covers the periphery of the electromagnet 544 is connected and fixed to the connection portion main body 541. The connecting part 54 is like this.

  One end of the shaft 55 is fixed to the shaft support portion 547, and the other end is inserted through the mounting portion 56 as shown in FIGS. 7 and 8, and is moved by the mounting portion 56.

  The mounting unit 56 is, for example, an air cylinder, and mounts the collection unit 6 with a connection unit to the detection unit 30 together with the shaft 55 and the coupling unit 54. The shaft movement range of the mounting portion 56 is determined in advance, and the collection unit 6 with a connection portion is mounted on the detection unit 30 so that there is no mechanical collision and the position is optimal for detection.

The rotation shaft 57 is connected to a rotation roller of the transport unit 52.
The transport motor 58 applies a transport force to the transport unit 52 via the rotating shaft 57 and transports the collection unit 6 with a connection unit on the transport unit 52.

  Subsequently, the operation of the radioactive gas monitor 5 will be described. First, the exchange of the collection unit 6 with a connection part will be described. It is assumed that a management control unit (not shown) of the radioactive gas monitor 5 determines that it is time to replace the collection unit 6 with a connection unit. In this case, the mounting unit 56 pulls out the collection unit 6 with a connection unit, and positions the collection unit 6 with a connection unit on the transport unit 52. In this case, it shall be in the connected state as shown to Fig.10 (a).

  When the magnetic force of the electromagnet 544 disappears in the state shown in FIG. 10A, the inner spring 545 moves the main body of the electromagnet 544 in the direction of the arrow e on the shaft side, as shown in FIG. Further, the outer spring 546 pushes the magnetic body 614 in the direction of arrow f to move the collection unit 6 with connection part in the direction of arrow g on the detection unit side, and disconnects the collection unit 6 with connection part from the connection part 54. A state as shown in FIG.

  Then, the transport motor 58 moves the transport unit 52. Then, the unused collection unit 6 with a connection part is installed in front of the coupling part 54 and the used collection unit 6 with a connection part is collected in the collection unit with connection part collection unit 53. Also in this case, the state is as shown in FIG.

  In the state shown in FIG. 10B, when the coupling portion 54 is brought close to the connection portion 61 while generating the magnetic force of the electromagnet 544, the iron core 544a attracts the magnetic body 614 as shown in FIG. 10C. . This force is strong and is attracted against the inner spring 545 and the outer spring 546. Then, the inner spring 545 moves the main body of the electromagnet 544 in the direction of the arrow h on the shaft side, pulls the connection portion 61 toward the connecting portion 54 side, and firmly fixes it. At this time, the radioactive gas inflow passages 12, 542, 612 communicate with each other, and the gas outflow passages 17, 543, 613 communicate with each other to form a flow passage.

  Subsequently, the mounting portion 56 pushes out the shaft 55 to move the collecting unit 6 with the connecting portion connected to the connecting portion 61, and the collecting unit with the connecting portion into the hole 31 a of the inner scintillator 31 of the detection unit 30. 6 is inserted, and the state shown in FIGS. 7, 9A and 9B is obtained. Subsequently, the exhaust gas is made to flow by operating the exhaust pump 46. The detection process is the same operation as the radioactive gas monitor 4 described above. Such detection is performed for a predetermined period, and when the time for replacement of the collection unit 6 with connection portion comes, the process returns to the top of this description and the same operation is repeated. Hereinafter, monitoring is continuously performed while exchanging a plurality of collection units 6 with connection portions. The radioactive gas monitor 4 is like this.

In addition, in this form, the structure which replaces | collects the collection unit 6 with a connection part by the connection part 54 and the mounting part 56 as shown in FIG. 9, FIG. 10 was employ | adopted. However, it goes without saying that the exchange mechanism is not limited to these configurations. For example, a commercially available robot hand is used as the mounting portion, and the used collecting unit 6 with a connecting portion is used by the robot hand. The collection unit 53 with connection is discarded, and then the unused collection unit 6 with connection unit is taken out from the collection unit storage unit 51 with connection and connected to the connection unit 54 and attached to the detection unit 30. It is good also as such a structure. Various exchange mechanisms can be selected for the collection unit 6 with a connecting portion.
In this embodiment, the radioactive gas monitor detector 3 is used as a detector. However, the radioactive gas monitor detector 2 described with reference to FIGS. 2 and 3 may be used.

According to such a radioactive gas monitor of the present invention, since the radioactive substance is continuously monitored while exchanging the collection unit, it is possible to greatly reduce the labor of maintenance of the worker. Moreover, the detector for radioactive gas monitor of this invention is employ | adopted, and it is made difficult to receive the influence of a background.
The radioactive gas monitor which performs the above-mentioned effect using the above-mentioned collection unit and the detector for radioactive gas monitor, and performs highly reliable monitoring can be provided.

In the above, the collection unit of this invention, the detector for radioactive gas monitors, and the radioactive gas monitor were demonstrated.
In the present invention, the specific example of the radioactive substance is described as radioactive iodine, and the specific example of the radioactive gas is described as iodine gas. In addition, the specific example of the adsorbent for radioactive iodine has been described as an active substance / iodinated charcoal.
However, it is not limited to activated carbon / iodination, and an adsorbent having the same function and performance can be used. Furthermore, by using various adsorbents that can adsorb radioactive substances other than iodine, the radioactive substances can be collected and detected. Thereby, it is not limited to radioactive iodine / iodine gas, but can be used for detection of various radioactive substances / radio gases.
Thus, it can be set as the collection unit corresponding to various radioactive substances, the detector for radioactive gas monitors, and a radioactive gas monitor.

  The collection unit, the detector for the radioactive gas monitor, and the radioactive gas monitor according to the present invention are used in medical facilities such as a nuclear power generation facility, a nuclear fuel reprocessing facility, a nuclear fuel facility, a particle beam utilization facility, a radioactive isotope use facility, and a hospital / inspection organization. It is used in various facilities such as facilities and incineration / melting facilities for solid waste, and contains radioactive materials (for example, radioactive iodine and Suitable for monitoring the release of compounds) and detection of leaks. In addition to this, it is suitable for detecting a very small amount of radiation, and its application is wide.

1: collection unit 11: container 11a: bottom 12: radioactive gas inflow path 12a: opening 13: adsorbent 13a: tip region 14: adsorbent filling lid 15: sealing part 16: intermediate space 17: gas outflow path 17a: Opening

2: Detector for radioactive gas monitor 20: Detection unit 21: Scintillator 21a: Hole 21b: Bottom 22: Photomultiplier tube 23: Shielding shield 24: Shaded area

3: Detector for radioactive gas monitor 30: Detection unit 31: Inner scintillator 31a: Hole 31b: Bottom 32: Outer scintillator 32a: Hole 32b: Bottom 33: Photomultiplier tube

4: Radioactive gas monitor 41: Preamplifier 42: Waveform discrimination calculation unit 43: Signal processing calculation unit 44: Output device 45: Radioactive gas inflow pipe 46: Exhaust pump

5: Radioactive gas monitor 51: Collection unit storage unit with connection part 52: Conveying part 53: Collection unit recovery unit with connection part 54: Connection part 541: Connection part body 542: Radioactive gas inflow path 543: Gas outflow path 544: Electromagnet 544a: Iron core 544b: Power supply section 545: Inner spring 546: Outer spring 547: Shaft support section 548: Connector 549: Tube 55: Shaft 56: Mounting section 57: Rotating shaft 58: Conveyance motor

6: Collection unit with connection part 61: Connection part 611: Connection part body 612: Radioactive gas inflow path 612a: Opening 613: Gas outflow path 613a: Opening 614: Magnetic body

Claims (6)

A container having a bottomed cylindrical shape and a storage space;
Disposed in the housing space, an adsorbent for adsorbing radioactive substances contained in the radioactive gas,
An adsorbent filling lid that is formed of a member through which a radioactive gas permeates and is arranged in the housing space and presses the adsorbent;
A sealing portion disposed in the housing space such that an intermediate space is formed between the adsorbent filling lid, and
A radioactive gas inlet passage opening is located near one end of the adsorbent to a bottom of the accommodating space,
A gas outlet passage opening is located in the intermediate space a point spaced from the other end of the adsorbent be the accommodating space,
With
Wherein the intermediate space and between the negative pressure, the passes through the radioactive gas flowing from the opening of the radioactive gas inlet passage the adsorbent, radioactive materials adsorb radioactive gas the suction by the suction through the gas outlet channel collection unit, characterized in that collecting the radioactive material by passing through a replenishing lid and said intermediate space flows out through the opening for the gas outlet channel. And the collection unit according to claim 1,
A detection unit that is mounted with the collection unit to detect;
A detector for a radioactive gas monitor, comprising:
The detection unit is
A well-type scintillator that is installed so that the bottom of the container faces the bottom of the hole and converts radiation emitted from the radioactive material adsorbed by the adsorbent into scintillation light;
A shielding shield that shields the background, with a large outer periphery of the scintillator ,
A photomultiplier tube for converting and amplifying scintillation light emitted from the scintillator into a current signal;
Radioactive gas monitor detector, wherein Rukoto equipped with. The collection unit according to claim 1 ;
A detection unit that is mounted with the collection unit to detect;
A detector for a radioactive gas monitor, comprising:
The detection unit is
Bottom of the container of the collection unit to the bottom of the hole is placed so as to face an inner scintillator well type which converts the radiation emitted from the radioactive substance adsorbed before Ki吸 Chakuzai the scintillation light,
A well-type outer scintillator that is installed so that the bottom of the inner scintillator faces the bottom of the hole, and converts background from the outside into scintillation light different from the waveform of the inner scintillator;
A photomultiplier tube that converts and amplifies the scintillation light emitted from the inner scintillator and the outer scintillator into a current signal;
A detector for a radioactive gas monitor, comprising: A container having a bottomed cylindrical shape and containing a storage space, an adsorbent disposed in the storage space and adsorbing a radioactive substance contained in a radioactive gas, and a bottom of the storage space and one end of the adsorbent A radioactive gas inflow passage in which an opening is located in the vicinity, and a gas outflow passage in which an opening is located in an intermediate space that is a location away from the other end of the adsorbent in the accommodating space, and the radioactive gas A collection unit that collects radioactive material by allowing the radioactive gas flowing in from the opening of the inflow passage to pass through the adsorbent and the radioactive gas adsorbed with the radioactive material to flow out of the opening of the gas outflow passage ;
A detection unit that is mounted with the collection unit to detect;
A detector for a radioactive gas monitor, comprising:
The detection unit is
Bottom of the container of the collection unit to the bottom of the hole is placed so as to face an inner scintillator well type which converts the radiation emitted from the radioactive substance adsorbed before Ki吸 Chakuzai the scintillation light,
Wherein and bottom of the inner scintillator is disposed so as to face the bottom of the hole, and the outer scintillator well type that converts the background from the outside before Symbol cie scintillation light different from the waveform of the inner scintillator,
A photomultiplier tube that converts and amplifies the scintillation light emitted from the inner scintillator and the outer scintillator into a current signal;
A detector for a radioactive gas monitor, comprising: 4. The detector for a radioactive gas monitor according to claim 2, wherein a radioactive gas supply unit is connected to the radioactive gas inflow passage, and a gas discharge unit is connected to the gas outflow passage. 5. A detector for a radioactive gas monitor mounted on the detection unit ;
A preamplifier for outputting the amplified voltage waveform signal by converting a current signal before Symbol photomultiplier tube voltage,
And the waveform discrimination operation section for outputting a radiation wave signals except the background discriminates a voltage waveform signal of said preamplifier,
A signal processing operation section for calculating the radioactivity concentration of the radioactive substance contained in the radioactive gas on the basis of the radiation waveform signal from the waveform discrimination computation unit,
A radioactive gas monitor characterized by comprising: The radioactive gas monitor according to claim 5,
A collection unit storage section for storing a plurality of the collection units;
A transport section for transporting the collection unit from the collection unit storage section;
Communicates the before and Kiho morphism gas inlet path the radioactive gas supply unit, and a connecting portion connected to the collecting unit while communicating with the gas outflow passage and the gas discharge portion,
A mounting portion to arrange the collecting unit to the detecting unit together with the connecting portion,
With
A radioactive gas monitor, wherein monitoring is continuously performed by a plurality of the collecting units.

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