JP6380326B2 - Sampling apparatus and sampling method - Google Patents

Description

  The present invention relates to a sample collection device and a sample collection method for collecting a sample gas to be analyzed in a sample collection container in a nuclear facility or the like.

  For example, a nuclear power generation facility, which is one of the nuclear facilities, is equipped with a radioactive gas monitor system for measuring the radioactive concentration emitted from radioactive materials in exhaust gas. The radioactive gas monitor system samples the exhaust gas from the plant exhaust pipe, guides it to a measurement container, and measures the radioactivity concentration released from the radioactive material in the exhaust gas with a low / high range radioactivity measuring device. At this time, the radiation level to be measured by the radioactivity measuring apparatus covers a wide measurement range from a low background level range during normal times to a high range assuming an abnormal situation such as an accident.

  The radioactive gas monitor system is equipped with a sample collection device for collecting a sample gas (measurement gas). The sample collection device collects a sample gas in a sample collection container provided in the sample collection device when an increase in radioactivity concentration is expected, such as in the case of an abnormality such as an accident. The operator removes the sampling container from the sampling apparatus and sends it to the analysis work, and specifies the nuclide of the radioactive substance contained in the sample gas (for example, see Patent Document 1).

  Patent Document 1 describes a vial sampler device as a sample collection device. Patent Document 1 describes that a sample gas is collected in a vial after evacuating the inside of a vial as a sample collection container by operating a vacuum pump ([0004], [0004] of Patent Document 1). 0028]).

JP-A-6-174605

  However, if the radioactivity concentration of the exhaust gas increases as expected at the time of the accident, the radioactivity concentration of the sample gas collected in the sample collection container increases. Then, it becomes difficult to remove the sample collection container from the sample collection device from the viewpoint of worker exposure.

  The present invention has been made in view of such problems, and the object of the present invention is to safely collect the sample gas in the sample collection container even in a situation where the radioactivity concentration of the sample gas is high. An object of the present invention is to provide a sampling device and a sampling method that can be used.

The sampling device of the present invention includes a piping system for taking sampling gas from a piping through which a sample gas for measuring a radioactivity concentration flows, and a mounting portion provided in the piping system to which a sampling container is attached and detached And a plurality of on-off valves provided in the piping system, a vacuum pump for evacuating the piping system, and a pressure reduction in the piping system by the vacuum pump in a state where the sampling container is attached to the mounting portion And a control unit for diluting the sample gas concentration in the sampling container by controlling the introduction of air through the on-off valve, and the piping system takes in the sample gas from the piping and the piping A first piping system having a flow path that can be returned to, a second piping system that includes a flow path branched from the first piping system and includes the mounting portion, and A third piping system having a flow path branched from the two piping systems and connected to the vacuum pump, wherein the third piping system is configured to supply air to the second piping system through the third piping system. A fourth piping system that can be introduced is connected, and the control unit depressurizes the sample gas in the sampling container and mixes it with air introduced from the fourth piping system, so that the sampling container The sample gas concentration is controlled to be a predetermined dilution .

  Another aspect of the present invention is a piping system for taking a sampling gas from a pipe through which a sample gas for measuring a radioactivity concentration flows, and a mounting portion provided in the piping system to which a sampling container is attached and detached. A sampling method in a sampling device comprising a plurality of on-off valves provided in the piping system, and a vacuum pump for evacuating the piping system, wherein the sampling container attached to the mounting portion With respect to the first step of introducing the sample gas taken from the piping, the flow path leading to the outside of the piping system is shut off and the space between the sampling container and the piping system is open, A second step of depressurizing the piping system connected to the sampling container with the vacuum pump; and disconnecting between the sampling container and the piping system. A third step of evacuating the piping system on the side with the vacuum pump; opening a space between the sampling container and the piping system; and introducing the atmosphere into the piping system to sample gas in the sampling container And a fourth step of diluting.

  According to the present invention, the sample gas can be safely collected in the sample collection container even in a situation where the radioactivity concentration of the sample gas is high.

It is a systematic diagram of the radioactive gas monitor system which concerns on this Embodiment. It is a systematic diagram of the sampling apparatus which concerns on this Embodiment. It is explanatory drawing for demonstrating the prior preparation step in the sample-collecting apparatus of this Embodiment. It is explanatory drawing for demonstrating the 1st step which introduce | transduces the sample gas into the sample collection container in the sample collection device of this Embodiment. It is explanatory drawing for demonstrating the 2nd step used as the gas pressure reduction operation | movement in the sample-collecting apparatus of this Embodiment. It is explanatory drawing for demonstrating the 3rd step used as the vacuum operation in the sample-collecting apparatus of this Embodiment. It is explanatory drawing for demonstrating the 4th step used as the air introduction operation | movement (front stage) in the sample-collecting apparatus of this Embodiment. It is explanatory drawing for demonstrating the 4th step used as the air introduction operation | movement (back | latter stage) in the sampling apparatus of this Embodiment. It is explanatory drawing for demonstrating the 5th step used as the sampling container removal operation | movement in the sampling apparatus of this Embodiment.

  Hereinafter, an embodiment of the present invention (hereinafter abbreviated as “embodiment”) will be described in detail. In the present embodiment, a radioactive gas monitor system that samples exhaust gas from a plant exhaust pipe (or exhaust pipe duct) of a nuclear power generation facility and monitors a radioactivity concentration released from a radioactive substance in the sampled exhaust gas (sample gas) It is an example which connected the sampling device to.

  FIG. 1 is a system diagram of a radioactive gas monitor system. The radioactive gas monitor system has a chamber 2 that can measure the radioactivity concentration of the sample gas drawn from the exhaust tube 20 in a low range and a high range. The sample gas drawn into the chamber 2 is configured to be collected by the sample collection device 30 connected to the radioactive gas monitor system.

  The radioactive gas monitor system includes a radioactivity measuring apparatus 1 that measures the radioactivity concentration of a sample gas. The radioactivity measuring apparatus 1 includes a chamber 2 through which sampled exhaust gas is guided, a low range detector 3 whose measurement target is a low range which is a relatively low range, and a relatively high range as a measurement target. And a high range detector 4.

  As shown in FIG. 1, the radioactivity measurement apparatus 1 is configured such that exhaust gas is guided to a chamber 2 via a sampling pipe 21 connected to an exhaust pipe 20 that exhausts exhaust gas in a nuclear power generation facility, and passes through a sampling pipe 22. Then, it is returned into the exhaust tube 20. A sampling nozzle 20 a serving as a gas intake port on the upstream side of the sampling pipe 21 is inserted into the exhaust cylinder 20. The sampling pipe 21 is provided with a dust collecting portion 23 made of dust collecting filter paper and activated carbon cartridges for removing particulate matter contained in the exhaust gas. Part of the exhaust gas that passes through the exhaust cylinder 20 is taken in from the sampling nozzle 20a, and is removed from the particulate matter and iodine by the dust collecting unit 23, and then supplied to the chamber 2 of the radioactivity measuring apparatus 1. In FIG. 1, the flow direction of the sample gas passing through the upstream sampling pipe 21 is indicated by an arrow A.

  The sample gas that has passed through the chamber 2 of the radioactivity measuring device 1 is returned to the exhaust pipe 20 through the sampling pipe 22 on the downstream side. In FIG. 1, the flow direction of the sample gas passing through the downstream sampling pipe 22 is indicated by an arrow B. The sampling pipe 22 is provided with a flow rate transmitter 24 for measuring the flow rate of the sample gas in the sampling pipe 22, a pump 27, and the like. The direction in which the sample gas taken in from the sampling nozzle 20a by the pump 27 returns to the exhaust pipe 20 via the chamber 2 of the radioactivity measuring apparatus 1 is controlled.

  The radiation detection signals output from the low range detector 3 and the high range detector 4 are output to the control device 25 via the corresponding preamplifiers 28 and 29, respectively. The control device 25 is configured to include a central processing unit (CPU), a storage device such as a ROM and a RAM, and counts and emits radiation detection signals that are weak electric signals amplified by the preamplifiers 28 and 29. It is converted into monitoring parameters such as active density and displayed and recorded. In the control device 25, conversion data in which the count number based on the radiation detection signal is compared with the radioactivity concentration (becquerel) is stored in advance, and is sent from the low range detector 3 and the high range detector 4. The radioactivity concentration can be calculated based on the count number of the radiation detection signal.

  The configuration of the radioactive gas monitor system shown in FIG. 1 is merely an example, and other configurations may be used. In the embodiment shown in FIG. 1, the radioactive gas monitor system is connected to the exhaust pipe 20, but may be connected to an exhaust pipe duct serving as a final duct connected to the exhaust pipe 20. The configuration of the radioactive gas monitor system when connected to the exhaust duct may be different from that shown in FIG.

  Next, the configuration of the sampling device 30 will be described. As shown in FIG. 1, the sampling device 30 is connected to a radioactive gas monitor system, and specifically, connected to a branch system 31 of a sampling pipe 22 on the downstream side. The sample collection device 30 is configured to collect a sample gas from the branch system 31, and is particularly configured to dilute a high concentration level sample gas. The configuration of the sampling device 30 will be described with reference to FIG. FIG. 2 is a system diagram of the sampling device 30.

  As shown in FIG. 2, the sample collection device 30 includes a piping system 10 for taking in sample gas for collection, a plurality of on-off valves 43, 44, 54, 58, 66, 67, 70, 78, and a regulating valve. 46, 68, a vacuum pump 69, and a control unit 34 configured to include a central processing unit (CPU), a storage device such as a ROM and a RAM, and to control the sampling device 30.

  The piping system 10 is connected to the branch system 31 of the sampling piping 22 through which the sample gas flows. The branch system 31 is provided with a plurality of branch pipes 35, 36, and 37 at intervals from the upstream side to the downstream side of the sampling pipe 22, and a flow path that branches from the sampling pipe 22 to the branch pipes 35, 36, and 37. Is secured.

  Opening connection portions 35 a, 36 a, and 37 a connected to the sample collection device 30 side are formed at the distal ends of the branch pipes 35, 36, and 37. In addition, on-off valves 38 and 39 are attached to the branch pipe 35 and the branch pipe 36 at intermediate positions. An on-off valve 40 is also provided in the middle of the sampling pipe 22 between the branch pipe 35 and the branch pipe 36. The on-off valves 38, 39, 40 may be automatic valves or manual valves. In the following description, the on-off valves 38, 39 and 40 are automatic valves and will be described as being controlled by the control device 25 shown in FIG. That is, the control device 25 controls the operation of the on-off valves 38, 39, and 40 at the time of collecting the sample gas, and adjusts so that the sample gas can flow from the sampling pipe 22 and the branch system 31 to the sample collecting device 30 side. It has a function. As the on-off valves 38, 39, 40, motor valves are exemplified.

  The piping system 10 includes a connection system 32 as a first piping system including a flow path that can take in the sample gas from the sampling pipe 22 and the branch pipe 35 and return the sample gas to the branch pipe 36 and the sampling pipe 22. In addition, a sampling system 50 as a second piping system including a flow path branched from the connection system 32 and a coupler 57 as a mounting portion to which the sampling container 56 is attached and detached, and a flow path branched from the sampling system 50 are provided. A vacuum system 51 is provided as a third piping system to which the vacuum pump 69 is connected.

  A main pipe 42 is provided in the connection system 32. The main pipe 42 of the connection system 32 is connected to the branch system 31 via connection parts 42a and 42b facing the connection parts 35a and 36a of the branch pipes 35 and 36. The main piping 42 of the connection system 32 includes an upstream piping portion 42c on the side of one connecting portion 42a, a downstream piping portion 42d on the side of the other connecting portion 42b, and an intermediate connecting between the upstream piping portion 42c and the downstream piping portion 42d. The piping part 42e is integrally formed.

  On-off valves 43 and 44 are provided in the middle of the upstream piping portion 42c and the downstream piping portion 42d, respectively. In addition, a bypass pipe 45 is provided that connects the upstream pipe portion 42c and the downstream pipe portion 42d in the middle and is located closer to the intermediate pipe portion 42e than the on-off valves 43 and 44, and the bypass pipe 45 extends from the upstream pipe portion 42c. A flow path to the downstream piping portion 42d is secured through the. A control valve 46 is provided in the middle of the bypass pipe 45. The on-off valves 43 and 44 are exemplified by solenoid valves, and the adjustment valve 46 is exemplified by a needle valve.

  A sampling system 50 is connected to the sample collection device 30. A vacuuming system 51 branched at an intermediate position is connected to the sampling system 50, and the atmosphere is introduced into the vacuuming system 51 as a fourth piping system capable of introducing the atmosphere into the sampling system 50 through the vacuuming system 51. A system 52 is connected.

  The collection line 50 is provided with a main pipe 53 having a flow path branched from the intermediate pipe portion 42e. In addition, an open / close valve 54 that is a three-way valve is provided at a connection position (branch position) between the intermediate pipe portion 42e and the main pipe 53 of the sampling system 50. In addition, a coupler 57 for attaching a sample collection container 56 with a ball valve 55 is provided at the tip of the main pipe 53 of the collection system 50. An on-off valve 58 is provided in the middle of the main pipe 53 located between the on-off valve 54 and the coupler 57. The on-off valve 58 is arranged on the coupler 57 side when viewed from the branch position S of the vacuum system 51. As the on-off valves 54 and 58, solenoid valves are exemplified.

  The evacuation system 51 includes a main pipe 62 that branches from the branch position S with the main pipe 53 of the sampling system 50 up and down in FIG. Thereby, a flow path is ensured between the main pipe 53 of the sampling system 50 and the main pipe 62 of the vacuum system 51. The main piping 62 of the evacuation system 51 is provided with a pressure transmitter 64 at one end, and an opening-shaped connecting portion at a position facing the connecting portion 37a of the branch piping 37 at the other end. 62b is provided. The pressure transmitter 64 is electrically connected to the control unit 34 via a cable or the like.

  The main piping 62 of the vacuum system 51 is provided with a screw plug 65 and an opening / closing valve 66 between the branch position S from the main piping 53 of the sampling system 50 and the pressure transmitter 64. In addition, the main pipe 62 of the vacuum system 51 includes an on-off valve 67, a control valve 68, and a control valve 68 between the branch position S from the main pipe 53 of the sampling system 50 and the connecting portion 62b from the side close to the branch position S. A vacuum pump 69 and an on-off valve 70 are attached. The vacuum pump 69 is electrically connected to the control unit 34 via a cable or the like. The on-off valves 67 and 70 are exemplified by solenoid valves, and the adjustment valve 68 is exemplified by a needle valve.

  Connection portions 35a, 36a, and 37a of the branch pipes 35, 36, and 37 shown in FIG. 2, and connection portions 42a, 42b, and 62b of the main piping 42 of the connection system 32 and the main piping 62 of the vacuum system 51, respectively. Connected and fixed. Thereby, the sample gas can be caused to flow from the branch system 31 into the sample collection device 30 and the sample gas can be returned from the sample collection device 30 to the branch system 31.

  The air introduction system 52 includes a main pipe 76. The main pipe 76 of the air introduction system 52 and the main pipe 62 of the vacuum system 51 are connected to secure a flow path. As shown in FIG. 2, the main pipe 76 of the air introduction system 52 is connected to the main pipe 62 of the vacuum system 51 at a position between the on-off valve 67 and the vacuum pump 69.

  As shown in FIG. 2, a filter 77 is provided at the end of the main pipe 76 of the air introduction system 52 so that air can flow in through the filter 77. As shown in FIG. 2, an on-off valve 78 is provided in the middle of the main pipe 76 of the air introduction system 52. As the on-off valve 78, a solenoid valve is exemplified.

  The on-off valve of the present embodiment is used for the on-off control of the flow path for introducing the sample gas to the piping system, gas decompression, and air introduction, and the system configuration of the piping system to which the on-off valve is attached, The number of on-off valves and the arrangement of the on-off valves are not limited.

  Note that the on-off valves 43, 44, 54, 58, 66, 67, 70, and 78 shown in FIG. 2 are merely examples, and valves having any configuration may be adopted. The on-off valves 43, 44, 54, 58, 66, 67, 70, 78 may be automatic valves or manual valves. When the on-off valves 43, 44, 54, 58, 66, 67, 70, 78 are automatic valves, these are electrically connected to the control unit 34 via a cable or the like and controlled thereby. Below, the case where the on-off valves 43, 44, 54, 58, 67, 70, 78 are automatic valves will be described as an example.

  A sample collection operation (sample collection method) by the sample collection apparatus when collecting a sample gas as a sample will be described with reference to FIGS. Hereinafter, in FIG. 3 to FIG. 9, main open / close valves are shown with a symbol “X”. A notation indicates a state where the valve is opened and the flow path is secured, and a notation indicates a state where the valve is closed and the flow path is blocked.

(Preliminary preparation steps)
As shown in FIG. 3, the sampling container 56 is attached to the coupler 57. At this time, the control unit 34 closes the on-off valve 54 to block the flow path between the main pipe 42 of the connection system 32 and the main pipe 53 of the sampling system 50. The on-off valve 54 is a three-way valve. The state in which the on-off valve 54 is opened indicates a state in which the flow path between the main pipe 42 of the connection system 32 and the main pipe 53 of the sampling system 50 is connected. The closed state means that the flow path between the main pipe 42 of the connection system 32 and the main pipe 53 of the sampling system 50 is blocked (the main pipe 42 of the connection system 32 is connected to the intermediate pipe part 42e from the upstream pipe part 42c. The flow path leading to the downstream piping part 42d is connected via Further, the control unit 34 brings the on-off valve 58 and the on-off valve 67 into the opened state and the on-off valve 78 into the closed state. Further, the adjustment valve 68 is adjusted for opening, and the ball valve 55 is opened. Thereby, the collection system 50, the sample collection container 56, and the evacuation system 51 are in a connected state.

  The system opening / closing is controlled by the control unit 34 as described above, and the vacuum pump 69 is operated by the control unit 34 to evacuate the vacuum system 51. Thereby, the inside of the sample collection container 56 can be evacuated via the collection system 50. This vacuum state is secured until the sample gas flows into the sample collection container 56. The pressure in the vacuum system 51 is measured by a pressure transmitter 64. FIG. 3 shows a piping system portion P1 evacuated by a dotted line. As shown in FIG. 3, the air introduction system 52 is also evacuated to the on-off valve 78.

(Introduction of sample gas into the sampling container: first step)
The control device 25 controls the on-off valves 38 and 39 of the branch system 31 of the radioactive gas monitor system to be opened and the on-off valve 40 to be closed (see FIG. 4).

  Further, in the connection system 32 of the sample collection device 30, the control unit 34 opens the on-off valves 43 and 44. In addition, the sample gas flows from the connection system 32 into the collection system 50 by opening the on-off valve 54 after a certain time has elapsed from the state of FIG. 3 until the residual gas in the pipe is replaced with the sample gas. A flow path is ensured so that it can.

  As shown in FIG. 4, the control unit 34 controls the on-off valve 67 and the on-off valve 78 to be closed while the on-off valve 58 is open. At this time, the ball valve 55 of the sample collection container 56 is kept open.

  As a result, the sample gas flows from the sampling pipe 22 through the branch system 31 into the connection system 32 and the sampling system 50. Then, the sample gas is introduced from the collection system 50 into the sample collection container 56. Thereby, 100% concentration sample gas can be introduced into the sample collection container 56.

  Here, if the radioactivity concentration measured by the radioactivity measuring apparatus 1 is equal to or less than the threshold value, the sampling container 56 is moved by the fifth step to be described later without performing the second to fourth steps. It can be removed and transferred to analysis work. On the other hand, if the radioactivity concentration measured by the radioactivity measurement apparatus 1 is equal to or greater than the threshold value, the control unit 34 performs a dilution operation described later. That is, the control unit 34 receives the radioactivity concentration measurement result from the radioactivity measurement apparatus 1, and determines the necessity of dilution and the degree of dilution when diluting based on the radioactivity concentration measurement result. Here, the case where the radioactivity concentration measured by the radioactivity measurement apparatus 1 exceeds the threshold value and the control unit 34 continues to perform the dilution operation will be described.

(Gas decompression operation: second step)
Next, as shown in FIG. 5, the control unit 34 performs control so as to close the on-off valve 54 and block the flow path between the connection system 32 and the sampling system 50. Thereby, the sample gas left in the connection system 32 can be returned to the sampling pipe 22 from the intermediate pipe part 42e via the downstream pipe part 42d and the branch pipe 36. Further, the control device 25 controls the open / close valves 38 and 39 of the branch system 31 to be closed and the open / close valve 40 of the sampling pipe 22 to be opened. Thereby, the flow path of the sample gas passing through the sampling pipe 22 can be secured.

  As shown in FIG. 5, the control unit 34 controls the open / close valve 58 and the open / close valve 67 to be opened, and controls the open / close valve 78 to be closed. At this time, both the ball valve 55 and the regulating valve 68 are kept open. That is, the flow path leading to the outside of the piping system 10 is blocked and the space between the sampling container 56 and the piping system 10 is opened.

  Then, the control unit 34 operates the vacuum pump 69 to reduce the pressure to a predetermined gas pressure. Thereby, the piping system 10 (piping system part P2) connected to the sampling container 56 shown by the dotted line in FIG. 5 is evacuated. For example, when the sample gas to be collected is diluted to 1/10, if the sample gas taken into the sample collection container 56 in the first step is 1 atm, the vacuum pump 69 reduces the pressure to 0.1 atm. Reduce pressure. The reduced pressure value can be measured by the pressure transmitter 64, and the measurement result is sent to the control unit 34.

  The degree of dilution is determined by the control unit 34 based on the radioactivity concentration measurement result from the radioactivity measuring device 1, and the reduced pressure value is determined according to the degree of dilution. For example, when the sample gas is diluted to a level at which safety can be ensured only by diluting the sample gas to 1/5, the sample gas taken into the sampling container 56 is 1 in the first step. If it is atmospheric pressure, the pressure is reduced by the vacuum pump 69 to 0.2 atmospheric pressure. Thus, the pressure of the reduced pressure is controlled according to the target dilution.

(Vacuum operation: 3rd step)
Next, as shown in FIG. 6, the ball valve 55 is closed from the state of FIG. 5 in order to shut off the sampling container 56 and the piping system 10. Other system open / close states are the same as those in FIG. In FIG. 6, the control unit 34 operates the vacuum pump 69 to control the blocked piping system 10 (piping system part P3) on the blocked side indicated by the dotted line in FIG. Note that the amount of sample gas collected can be calculated by accurately measuring the vacuum pulling pressure and the sample gas pressure collected in the sample collection container 56 with the pressure transmitter 64. Although it is not necessary, even if a general vacuum pump 69 is used, it becomes 1 Torr or less.

  In FIG. 6, since the ball valve 55 of the sampling container 56 is closed, the sampling container 56 is not affected by the vacuum. That is, the inside of the sampling container 56 is maintained at a state of 0.1 atm when the sample gas is diluted by 1/10.

(Air introduction operation: 4th step)
Next, from the third step described above, as shown in FIG. 7, the control unit 34 controls the open / close valve 78 between the sampling container 56 and the piping system 10 to be opened. At this time, the ball valve 55 of the sample collection container 56 is closed. The other system open / closed states are the same as in FIG.

  As shown in FIG. 7, when the on-off valve 78 is opened, air (atmospheric pressure air) is introduced from the air introduction system 52 toward the vacuum system 51 and the sampling system 50 through the filter 77. Can do. As a result, the air introduction system 52, the vacuum system 51, and the sampling system 50 are filled with 1 atmosphere of air.

  Next, as shown in FIG. 8, the ball valve 55 of the sampling container 56 is opened. As a result, air flows into the sampling container 56. At this time, sample gas of 0.1 atm is already in the sample collection container 56. Since the air introduction system 52, the vacuum system 51, and the sampling system 50 are filled with air at 1 atm, the sample gas container 56 has 0.1 atm of sample gas so that the inside of the sampling container 56 is also 1 atm. 0.9 atmosphere of air is mixed. As a result, the sample gas is diluted to 1/10 in the sample collection container 56. When the sample gas concentration in the sample collection container 56 is diluted to 1/10 of the collected raw gas, the dilution operation is finished here. On the other hand, since the radioactivity concentration of the sample gas is very high, the radioactivity concentration in the sampling container 56 may not be lowered to a level at which sufficient safety can be ensured by one dilution operation. In this case, the sample gas in the sampling container 56 is diluted to a level at which safety can be ensured by repeating the dilution operation from step 2 to step 4. Then, the second to fourth steps are repeated until the target dilution is reached.

(Sample collection container removal operation: fifth step)
Subsequently, from the state of FIG. 8, the control unit 34 controls the open / close valve 58 to be closed. In FIG. 8, the on-off valve 78 is also controlled to be closed. Then, the ball valve 55 of the sample collection container 56 is closed, and the sample collection container 56 is removed from the coupler 57 as shown in FIG.

  By each operation described above, the sample gas diluted in the sample collection container 56 can be collected, and the safety and workability can be improved as compared with the conventional case.

  Moreover, it is possible to easily and appropriately dilute the sample by each operation for diluting the sample by the sample collection device 30 described above.

  According to the sampling apparatus of the present invention, even when the radioactivity concentration of the gas to be measured reaches a high concentration level in the event of an abnormality such as an accident, the gas to be measured can be sampled in a diluted state. It can be used as appropriate.

DESCRIPTION OF SYMBOLS 1 ... Radioactivity measuring device 2 ... Chamber 3 ... Low range detector 4 ... High range detector 10 ... Piping system 20 ... Exhaust pipe 21, 22 ... Sampling piping 25 ... Control device 30 ... Sampling device 31 ... Branch system 32 ... Connection system (first piping system)
34 ... Control unit 38, 39, 40 ... Open / close valve 42, 53, 62, 76 ... Main piping 43, 44, 54, 58, 66, 67, 70, 78 ... Open / close valve 46, 68 ... Control valve 50 ... Sampling system (Second piping system)
51 ... Vacuum drawing system (third piping system)
52 ... Air introduction system (fourth piping system)
55 ... Ball valve 56 ... Sampling container 57 ... Coupler 64 ... Pressure transmitter 69 ... Vacuum pump 77 ... Filter

Claims (5)

A piping system for taking a sample gas for sampling from a pipe through which the sample gas for measuring the radioactivity concentration flows;
A mounting portion provided in the piping system to which a sampling container is attached and detached;
A plurality of on-off valves provided in the piping system;
A vacuum pump for evacuating the piping system;
In a state where the sampling container is attached to the attachment portion, the pressure reduction in the piping system by the vacuum pump and the introduction of air through the on-off valve are controlled to dilute the sample gas concentration in the sampling container. A control unit,
Equipped with a,
The piping system includes a first piping system including a flow path capable of taking in the sample gas from the piping and returning the sample gas to the piping, a flow path branched from the first piping system, and the mounting portion. A second piping system provided, and a third piping system including a flow path branched from the second piping system and connected to the vacuum pump,
A fourth piping system capable of introducing air into the second piping system through the third piping system is connected to the third piping system,
The control unit decompresses the sample gas in the sample collection container and mixes it with air introduced from the fourth piping system so that the sample gas concentration in the sample collection container becomes a predetermined dilution. A sampling device characterized by controlling .   2. The sample according to claim 1, wherein the control unit determines a dilution degree of a sample gas concentration or necessity of dilution based on a radioactivity concentration measurement result of a radioactivity measuring device provided in the pipe. Collection device.   3. The sampling device according to claim 1, wherein the control unit determines a pressure reduction level in the piping system by the vacuum pump according to a dilution degree of a sample gas concentration.   The control unit repeats pressure reduction in the piping system by the vacuum pump and introduction of air through the on-off valve until a sample gas concentration in the sampling container falls below a predetermined value. The sampling device according to any one of claims 1 to 3. A piping system for taking sampling gas from a pipe through which a sample gas for measuring radioactivity concentration flows, a mounting part provided in the piping system to which a sampling container is attached and detached, and provided in the piping system A sampling method in a sampling device comprising a plurality of on-off valves and a vacuum pump for evacuating the piping system,
A first step of introducing the sample gas taken from the pipe into the sampling container attached to the attachment portion;
Secondly, the flow path leading to the outside of the piping system is shut off and the piping system connected to the sampling container is decompressed by the vacuum pump in a state where the sampling container and the piping system are open. Steps,
A third step of blocking between the sampling container and the piping system and evacuating the piping system on the blocked side with the vacuum pump;
And a fourth step of opening the space between the sampling container and the piping system and introducing air into the piping system to dilute the sample gas in the sampling container. .

Images