JPH0921784A - Gas constituent monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the monitoring capacity for atmosphere in a reactor storage container by calibrating sensitivity using a standard gas over a wide range. SOLUTION: The gas constituent monitoring device introduces a measurement gas taken out of a container 1 to be monitored to a measurement line, detects the concentration of a monitoring gas by a detector 26 provided on the measurement line, monitors the gas concentration based on the detection result, and discharge gas the measurement gas after the measurement is completed into the container 1 to be monitored. It connects a hydrogen occlusion tank 37 to the measurement line via bypass valves 38 and 39 in parallel so that the measurement gas flowing to the measurement line can be bypassed to the hydrogen occlusion tank 37 with a function for adsorbing hydrogen gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring device used in the field of reactor instrumentation, and more particularly to a containment vessel atmosphere monitoring device for measuring the concentration of oxygen and hydrogen contained in the atmosphere in the reactor containment vessel. (Hereinafter referred to as “CAMS”).

[0002]

Nuclear power plants are equipped with CAMS to monitor the atmosphere within the containment vessel. C
AMS measures hydrogen and oxygen in the containment vessel atmosphere as one index for confirming safety. CAM
The hydrogen / oxygen concentration measuring system of S is arranged in a sampling rack installed outside the containment vessel for reasons of environment resistance of the oxygen detector and the hydrogen detector and maintenance and inspection reasons. It is called a sampling method because the atmospheric gas is sampled from the containment vessel and introduced into the sampling rack.

FIG. 4 shows an example of the structure of a hydrogen / oxygen concentration measuring system adopting a sampling method. The reactor containment vessel 1 and the sampling rack 2 are connected by piping, and the atmospheric gas in the reactor containment vessel 1 is drawn into the sampling rack 2 by the suction pump 3 in the rack. After the moisture contained in the sampling gas is removed by the dehumidifier 4, the oxygen detector 5 and the hydrogen detector 6 measure the hydrogen and oxygen concentrations, respectively. The measured dry gas is drawn by the exhaust pump 7 and returned to the reactor containment vessel 1 via the check valve 8. On the other hand, the moisture removed from the sampling gas by the dehumidifier 4 is measured by the drain measuring device 9 and then returned to the reactor containment vessel 1 again via the drain valve 10.

The sampling rack 2 and the CAMS board 12 are connected by a signal line and a power supply line to supply power from the CAMS board 12 to each constituent element of the sampling rack 2 and from each constituent element of the sampling rack 2 to the CAMS board 12. Transmit measurement data to.

The CAMS board 12 is a sampling rack 2
Data is transmitted to and received from and via the interface 13. The computer 14 executes the moisture correction calculation of the measured value. Here, the concentration values measured by the oxygen detector 5 and the hydrogen detector 6 are on a dry basis, whereas the atmospheric gas in the actual reactor containment vessel 1 is on a wet basis. Therefore, the computer 14 uses the drain amount measurement value transmitted from the level meter 11 to convert the dry base hydrogen / oxygen measurement value into the wet base to perform the atmosphere monitoring.

Further, a calibration gas cylinder containing a hydrogen standard gas is connected to a measurement line in a sampling rack via a calibration gas valve 16, and the line valve 17 is closed and the calibration gas valve 16 is opened to release hydrogen. It is configured so that standard gas can be supplied to the measurement line. The hydrogen standard gas for calibration is used in the reactor containment vessel 1 after the hydrogen detector 6 has been measured.
Exhausting to.

In addition to the measurement of hydrogen / oxygen by the above-mentioned hydrogen / oxygen concentration measuring system, trace gas analysis of the atmospheric gas in the reactor containment vessel 1 is performed. The atmospheric gas of the reactor containment vessel 1 was collected in a sample container, and the sample container was carried to a place where a trace gas analysis facility was prepared.

[0008]

However, in the hydrogen / oxygen concentration measuring system described above, the hydrogen standard gas for calibration is exhausted to the reactor containment vessel 1 after the measurement is completed, so that the hydrogen standard gas with a high concentration is used as the hydrogen standard gas. Hydrogen gas cannot be used. As a result, the sensitivity of the detector was calibrated based on the test results with low concentration hydrogen standard gas, and it was not possible to calibrate the sensitivity with a wide range of standard gas from low concentration to high concentration.

Further, since the trace gas analysis of the atmospheric gas in the reactor containment vessel 1 is carried out by collecting the ambient gas in a sample container and carrying it to another place where the equipment is well equipped, the trace gas analysis is always executed. It was not equipped with such equipment.

The present invention has been made in view of the above circumstances, and enables sensitivity calibration using a wide range of standard gas from low concentration to high concentration, and also enables trace gas analysis at all times. By doing so, it is an object of the present invention to provide a containment vessel atmosphere monitoring device capable of improving the ability to monitor the atmosphere in the containment vessel.

[0011]

In order to achieve the above object, the present invention takes the following measures. The present invention corresponding to claim 1 introduces a measurement gas taken out from a container to be monitored into a measurement line, detects the hydrogen concentration in the measurement gas with a hydrogen detector provided in the measurement line, and Based on monitoring the hydrogen concentration in the measurement gas based on the gas component monitoring device for releasing the measurement gas after the measurement into the monitoring target container, the measurement line is provided in a hydrogen storage tank having a function of adsorbing hydrogen gas. The hydrogen storage tank is connected in parallel to the measurement line via a bypass valve so that the flowing measurement gas is bypassed, and when performing a calibration test of the hydrogen detector by introducing a standard gas into the measurement line, The measurement gas flowing through the measurement line was configured to pass through the hydrogen storage tank.

According to the present invention corresponding to claim 1, a hydrogen storage tank having a function of adsorbing hydrogen gas is connected in parallel to the measurement line via a bypass valve. When the standard gas is introduced into the measurement line to perform the calibration test of the hydrogen detector, the bypass valve is switched so that the measurement gas flowing through the measurement line passes through the hydrogen storage tank. Since the hydrogen component in the standard gas flowing into the hydrogen storage tank from the measurement line is adsorbed in the tank, the hydrogen concentration in the standard gas is significantly reduced. The standard gas having the reduced hydrogen concentration is returned to the measurement line and then released into the monitored container.

In the present invention corresponding to claim 2, the measuring gas taken out from the container to be monitored is introduced into the measuring line, and the oxygen concentration in the measuring gas is detected by the oxygen detector provided in the measuring line. In the gas component monitoring device that monitors the oxygen concentration in the measurement gas based on the detection result, and releases the measurement gas after the measurement into the monitoring target container, the oxygen compound material filled with the compound compound that combines with the oxygen gas. The oxygen compound tank is connected in parallel to the measurement line via a bypass valve so that the measurement gas flowing in the measurement line is bypassed to the tank, and a standard gas is introduced into the measurement line to introduce the oxygen detector. When performing the calibration test, the measurement gas flowing through the measurement line was configured to pass through the oxygenated material tank.

According to the second aspect of the present invention, the oxygenated compound material tank filled with the compounded material for compounding oxygen gas is connected in parallel to the measurement line via the bypass valve. When introducing a standard gas into the measurement line and performing a calibration test of the oxygen detector, the bypass valve is switched so that the measurement gas flowing through the measurement line passes through the oxygen-containing mixture tank. The oxygen component in the standard gas flowing from the measurement line into the oxygen compound tank is combined and removed in the tank, so that the oxygen concentration in the standard gas is significantly reduced. The standard gas with the reduced oxygen concentration is returned to the measurement line and then released into the monitored container.

In the present invention corresponding to claim 3, the measurement gas taken out from the container to be monitored is introduced into the measurement line, and the oxygen concentration and the oxygen concentration in the measurement gas are measured by the oxygen detector and the hydrogen detector provided in the measurement line. Detects the hydrogen concentration, monitors the oxygen concentration and hydrogen concentration in the measurement gas based on the detection result,
In the gas component monitoring device for releasing the measurement gas after the measurement into the container to be monitored, the measurement line flows through an analysis rack equipped with a trace gas analysis function capable of obtaining the gas partial pressure ratio of the gas component by mass spectrometry. The analysis rack is connected to the measurement line through a branch valve so that a part of the measurement gas flows in, and the gas partial pressure ratio of the measurement gas obtained in the analysis rack and the detection results of the oxygen detector and the hydrogen detector. And was input to the computer to perform quantitative trace gas analysis.

According to the present invention corresponding to claim 3, an analysis rack having a trace gas analysis function is connected to a measurement line through a branch valve, and a part of the measurement gas flowing through the measurement line is passed through the branch valve. Flow in. In the analysis rack, the gas partial pressure ratio of each gas is obtained by mass spectrometry of the measurement gas.
The gas partial pressure ratio data obtained by the analysis rack and the detection results of the oxygen detector and hydrogen detector are input to the computer, and quantitative trace gas analysis is performed.

According to a fourth aspect of the present invention, in the gas component monitoring apparatus according to the third aspect, an opening degree from a computer is provided on a gas passage for guiding a part of the measurement gas from the branch valve to the analysis rack. Adjustable variable leak valve is provided.

According to the present invention corresponding to claim 4, the opening degree of the variable leak valve provided on the gas passage for guiding a part of the measurement gas from the branch valve to the analysis rack can be adjusted by a computer. Therefore, the sensitivity can be adjusted by changing the opening of the variable leak valve.

According to the present invention corresponding to claim 5, in the gas component monitoring device according to claim 3 or 4, hydrogen and oxygen obtained from the detection results of the oxygen detector and the hydrogen detector are calculated by the computer. And the concentration ratio of hydrogen and oxygen based on the gas partial pressure ratio of the measurement gas obtained by the analysis rack are compared to diagnose the soundness.

According to the present invention corresponding to claim 5, the concentration ratio of hydrogen and oxygen obtained from the detection results of the oxygen detector and the hydrogen detector in the computer and the gas partial pressure ratio of the measurement gas obtained in the analysis rack are calculated. The hydrogen and oxygen concentration ratios based are compared. If the two values are different from each other over a predetermined range, it can be diagnosed as abnormal, and if they are almost the same, it can be diagnosed as normal.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. (First Embodiment) FIG. 1 mainly shows the configuration of the hydrogen / oxygen concentration measuring system portion in the CAMS of the present embodiment.
In this embodiment, a sampling rack 20 connected to the reactor containment vessel 1 via a pipe, and a CAMS connected to the sampling rack 20 via a signal line and a power line.
And a board 21.

The sampling rack 20 has a dehumidifier 22 that removes moisture from the sampling gas introduced from the reactor containment vessel 1 into the rack via piping. A suction pump 24 is connected to the dehumidifier 22 via a line valve 23,
An oxygen detector 25 and a hydrogen detector 26 are arranged on the measurement line formed on the outlet side of the suction pump 24 to measure the concentrations of oxygen and hydrogen in the sampling gas, respectively. A check valve 27 and a bypass line valve 28 are inserted into a measurement line extending to the outlet side of the hydrogen detector 26, and the measurement line is drawn out of the rack via an exhaust pump 29 to contain the reactor. 1 to the sample outlet. Further, the dehumidifier 22 is provided with a drain measuring device 31 for storing the water removed from the sampling gas. A water level of the drain measuring device 31 is detected by a level meter 32 attached to the drain measuring device 31. The drain measuring device 31 is connected to the drain discharge port of the reactor containment vessel 1 via a drain valve 33. The calibration gas cylinder 34 is connected to the measurement line in the front stage of the suction pump 24 via the calibration valve 35.

In this embodiment, a bypass 36 is provided between the check valve 27 and the exhaust pump on the measurement line. A tank facility 37 for adsorbing hydrogen and oxygen is provided in the middle of the bypass path 36, and bypass valves 38 and 39 are provided on the inlet side and the outlet side of the tank facility 37, respectively. The tank facility 37 has a configuration in which a hydrogen storage tank and an oxygenated compound material tank are arranged in series. The hydrogen storage tank stores a metal capable of storing hydrogen such as palladium or titanium. The oxygenated compound tank contains an oxygenated compound material such as iron powder that combines with oxygen to absorb oxygen.

The computer 40 installed on the CAMS board 21 is connected to the sampling rack 20 via the interface 41.
It sends and receives data to and from each component inside. The operation of this embodiment configured as described above will be described.

When measuring hydrogen / oxygen, the computer 40 gives a command to the components of the sampling rack 20 through signal lines to open the line valves 23 and 28 and to calibrate the valve 35 for calibration.
The bypass valves 38 and 39 are closed. After the sampling gas sucked from the reactor containment vessel 1 to the sampling rack 20 by the suction pump 24 is dehumidified by the dehumidifier 22, the oxygen concentration in the sampling gas is introduced to the oxygen detector 25 and the hydrogen detector 26. The hydrogen concentration is measured. The measured values at the oxygen detector 25 and the hydrogen detector 26 are transmitted to the computer 40 via signal lines. On the other hand, the water removed from the sampling gas by the dehumidifier 22 collects in the drain measuring device 31, and the water level thereof is transmitted from the level meter 32 to the computer 40. In the computer 40, the oxygen concentration and hydrogen concentration received from the detector are subjected to moisture correction calculation with the moisture data received from the level meter 32.

When performing the calibration test of the hydrogen detector 26 (or the oxygen detector 25), the computer 40 gives a command to the constituent elements of the sampling rack 20 through the signal line to close the line valves 23 and 28 and to calibrate the calibration valve. 35, the bypass valves 38 and 39 are opened. The concentration of the hydrogen standard gas introduced from the calibration gas cylinder 34 into the measurement run through the calibration valve 35 is measured by the hydrogen detector 26, and the measured value is transmitted to the computer 40 via the signal line.

The hydrogen standard gas whose concentration has been measured by the hydrogen detector 26 has the line valve 28 closed, so that the bypass valve 3
6 is introduced into the bypass path 36 through the tank equipment 37
It is put in the hydrogen storage tank. Since hydrogen is adsorbed in the hydrogen storage tank, the hydrogen concentration of the hydrogen standard gas is significantly reduced. It becomes a gas whose hydrogen concentration is significantly lower than the hydrogen standard gas used for the calibration test, and exits the hydrogen storage tank, then enters the oxygenation material tank and absorbs oxygen in the gas. Here, the oxygen compounding reaction in the oxygen compounding material tank is accompanied by heat generation, but there is no problem because the hydrogen concentration is greatly reduced.

The gas whose hydrogen concentration and oxygen concentration are lowered when passing through the oxygen-containing mixture tank is discharged into the reactor containment vessel 1 by the exhaust pump 29 through the bypass valve 39. As described above, according to the present embodiment, the bypass line 36 is provided on the measurement line formed in the sampling rack 20 on the rear side of the detector, and the hydrogen storage tank and the oxygenation material tank are provided in the bypass line 36. Therefore, even if a high-concentration hydrogen standard gas or oxygen standard gas is introduced from the calibration gas cylinder 34 into the measurement line, the tank facility 37 lowers the concentration to a level at which there is no problem, and then the reactor containment vessel 1
Can be released to. Therefore, the calibration test of the detector can be carried out by using the high concentration hydrogen standard gas and oxygen standard gas, and the calibration in a wider range becomes possible.

(Second Embodiment) FIG. 2 shows C of the present embodiment.
It mainly shows the configuration of the hydrogen / oxygen concentration measurement system part in AMS. The same parts as those in the first embodiment described above are designated by the same reference numerals.

In this embodiment, an analysis rack 50 having a trace gas analysis function is connected to a measurement line formed on the sampling rack 20 via branch valves 51 and 52.
The branch valve 51 is provided upstream of the check valve 27 in the measurement line, and introduces a part of the sampling gas into the analysis rack 50. The branch valve 52 is provided in the measurement line after the check valve 27, and returns the sampling gas of the analysis rack 50 to the measurement line.

FIG. 3 shows an example of the structure of the analysis rack 50. The analysis rack 50 is a vacuum container 5 provided in the rack.
3 is connected to the branch valve 51 via a variable leak valve 54. The opening of the variable leak valve 54 is controlled by a variable leak valve controller 55 that operates according to a command from the computer 40. The internal pressure of the vacuum container 53 is measured by a pressure gauge 56 and given to the variable leak valve 54.
On the other hand, a turbo molecular pump 57 and a rotary pump 58 are connected to an exhaust pipe communicating with the inside of the vacuum container 53 in order to vent gas without breaking the atmosphere for vacuum. The analysis rack 50 is provided with a mass analyzer head 59 for performing mass analysis of the sampling gas drawn into the vacuum container 53. The mass analyzer head 59 is controlled by a controller 60 which operates according to a command from the calculator 40. Reference numeral 16 is a thermometer that detects the temperature of the vacuum container 53.

The operation of this embodiment configured as described above will be described. When a trace gas analysis is performed on the analysis rack 50, the branch valves 51 and 52 on the measurement line are opened by a command from the computer 40, and the controller 55 opens the variable leak valve 54 to open the variable leak valve from the measurement line. A measurement gas is introduced into the vacuum container 53 via 54. Further, the measurement gas in the vacuum container 53 is supplied to the vacuum container 5 by the turbo molecular vacuum pump 57 and the rotary pump 58.
3 and is returned to the measuring line through the branch valve 52.

At this time, the amount of measurement gas introduced into the vacuum container 53 via the variable leak valve 54 can be extremely small, so that the gas flow rate in the measurement line is hardly affected.

The measurement gas introduced into the vacuum container 53 is subjected to mass analysis by the mass analysis head 59, and the partial pressure ratio of each gas contained in the measurement gas is accurately obtained. This measurement data is sent from the controller 60 via the signal line to the CAMS board 21.
To the computer 40 via the interface 41.

The computer 40 receives the measurement data of the hydrogen / oxygen concentration measurement carried out in the sampling rack 20 simultaneously with the trace gas analysis from the analysis rack 50. When the filament of the mass analysis head 59 deteriorates, the ionization amount of the measurement gas changes, so the mass analysis head 59
The measurement value received from the instrument needs to be corrected for its absolute value. In the computer 40, noting that the composition ratio of the measurement gas is the same even if the ionization amount changes, the partial pressure ratio of each gas contained in the measurement gas received from the mass spectrometry head 59 and the partial pressure ratio at the same time. Based on the hydrogen / oxygen partial pressure ratios received from the oxygen detector 25 and the hydrogen detector 26, the calculation for obtaining the absolute value of each gas contained in the measurement gas is executed. As a result of this calculation, each gas contained in the measurement gas is quantitatively measured.

In the computer 40, the soundness of the measurement system is diagnosed by comparing the partial pressure ratio of hydrogen / oxygen received from the mass spectrometric head 59 with the partial pressure ratio of hydrogen / oxygen received from the sampling rack 20. To do. If both are normal, the two partial pressure ratios will match. If the two values differ from each other over a predetermined range, it is determined that an abnormality has occurred in one of them, and an operation such as valve switching is executed to disconnect the abnormal portion. For example, the branch valves 51 and 52
Is closed by a command from the computer 40 to separate the gas path.

When measuring a trace amount of gas quantitatively,
The stability of the gas flow rate affects the measurement accuracy. In the present embodiment, the computer 40 removes the measurement error due to the change in the gas flow rate by adding the correction calculation according to the change in the gas flow rate.

The opening of the variable leak valve 54 is usually set to a relatively small value in order to suppress the deterioration of the filament of the mass analysis head 59, but in the analysis of a small amount of gas, the opening should be increased to improve the sensitivity. Is also possible.

As described above, according to this embodiment, since the analysis rack 50 having the trace gas analysis function is always connected to the measurement line formed in the sampling rack 20, the quantitative measurement of the trace gas analysis is performed. Will always be possible.

According to this embodiment, since the partial pressure ratio measurement data of the measurement gas is corrected to the quantitative value in the computer 40, the gas flow rate stabilizing mechanism necessary for the quantitative analysis of the trace gas is not required, and the device It is possible to achieve simplification and cost reduction.

According to this embodiment, the partial pressure ratio of hydrogen / oxygen is obtained from the trace gas analysis result, so that the soundness of the CAMS measurement system can be diagnosed. The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the CAMS can be configured by attaching the analysis rack 50 of the second embodiment to the first embodiment.

[0042]

As described above in detail, according to the present invention, it is possible to perform sensitivity calibration using a wide range of standard gas from low concentration to high concentration, and to improve the monitoring capability of the atmosphere inside the reactor containment vessel. An atmosphere monitoring device in a containment vessel that can be improved can be provided.

Further, according to the present invention, it is possible to provide a containment vessel atmosphere monitoring device which can improve the ability to monitor the atmosphere in the reactor containment vessel by enabling the trace gas analysis at all times.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a CAMS according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a CAMS according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of an analysis rack provided in the CAMS of the second embodiment.

FIG. 4 is a block diagram of a conventional CAMS.

[Explanation of symbols]

1 ... Reactor containment vessel, 20 ... Sampling rack, 21
… CAMS board, 22… Dehumidifier, 23… Line valve, 24…
Suction pump, 25 ... Oxygen detector, 26 ... Hydrogen detector, 2
7 ... Check valve, 28 ... Bypass line valve, 29 ... Exhaust pump, 31 ... Drain measuring device, 32 ... Level meter, 33 ... Drain valve, 34 ... Calibration gas cylinder, 35 ... Calibration valve, 36
... Bypass passage, 37 ... Tank equipment, 38, 39 ... Bypass valve, 40 ... Computer, 50 ... Analysis rack, 51, 52 ...
Branch valve, 53 ... Vacuum container, 54 ... Variable leak valve,
55 ... Variable leak valve controller, 59 ... Mass spectrometer head.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junsei Endo No. 1 in Toshiba Fuchu factory, Fuchu-shi, Tokyo (72) Inventor Shigeru Suzuki No. 1 Toshiba-machi in Fuchu, Tokyo Tokyo Fuchu factory, Ltd.

Claims (5)

[Claims] 1. A measurement gas taken out from a container to be monitored is introduced into a measurement line, a hydrogen detector provided in the measurement line detects the hydrogen concentration in the measurement gas, and the measurement gas is measured based on the detection result. In the gas component monitoring device that monitors the hydrogen concentration of the gas and releases the measured gas after the measurement into the monitored container, the measured gas flowing through the measuring line is bypassed to the hydrogen storage tank that has the function of adsorbing the hydrogen gas. As described above, the hydrogen storage tank is connected in parallel to the measurement line via a bypass valve, and a standard gas is introduced to the measurement line to perform a calibration test of the hydrogen detector. A gas component monitoring device, wherein gas passes through the hydrogen storage tank. 2. The measurement gas taken out from the monitored container is introduced into a measurement line, the oxygen concentration in the measurement gas is detected by an oxygen detector provided in the measurement line, and the measurement gas is measured based on the detection result. In the gas component monitoring device that monitors the oxygen concentration of the, and discharges the measurement gas after the measurement into the monitoring target container, the measurement that flows through the measurement line to the oxygenation compound material tank filled with the compound material that combines with the oxygen gas. When the oxygen compound tank is connected in parallel to the measurement line via a bypass valve so that the gas is bypassed, and the standard gas is introduced into the measurement line to perform a calibration test of the oxygen detector, the measurement is performed. A gas component monitoring device characterized in that a measuring gas flowing through a line passes through the oxygenated compound tank. 3. The measurement gas taken out of the container to be monitored is introduced into a measurement line, the oxygen concentration and hydrogen concentration in the measurement gas are detected by an oxygen detector and a hydrogen detector provided in the measurement line, and the detection is performed. A gas component monitoring device that monitors the oxygen concentration and hydrogen concentration in the measurement gas based on the results and discharges the measurement gas into the monitoring target container after the measurement is completed, and obtains the gas partial pressure ratio of the gas component by mass spectrometry. The measurement rack is connected to the measurement line via a branch valve so that a part of the measurement gas flowing through the measurement line flows into the analysis rack having a trace gas analysis function, and the measurement gas obtained by the analysis rack is obtained. The gas component monitoring device, wherein the gas partial pressure ratio and the detection results of the oxygen detector and the hydrogen detector are input to a computer to perform quantitative trace gas analysis. 4. A variable leak valve whose opening can be adjusted by a computer is provided on a gas passage for guiding a part of the measurement gas from the branch valve to the analysis rack. Gas component monitoring device. 5. The computer calculates the concentration ratio of hydrogen and oxygen obtained from the detection results of the oxygen detector and the hydrogen detector, and hydrogen and oxygen based on the gas partial pressure ratio of the measurement gas obtained by the analysis rack. The gas component monitoring device according to claim 3 or 4, further comprising a function of diagnosing soundness by comparing with a concentration ratio.