Dual-gas analysis instrument for nuclear power station

Abstract

The invention discloses a dual-gas analysis instrument for a nuclear power station. The dual-gas analysis instrument comprises a control cabinet located in a first area and a sampling test cabinet located in a second area, the control cabinet is in signal connection with the sampling test cabinet; the sampling test cabinet comprises a sampling pipeline and a monitoring module which are communicated in sequence; the monitoring module comprises an oxygen monitoring module and a hydrogen monitoring module; wherein the monitoring module is also connected with a purging pipeline and a calibration pipeline; the sampling test cabinet is communicated with the nuclear waste gas pipeline, continuous sampling is performed from the sampling test cabinet through the sampling pipeline, and then the hydrogen and oxygen content in the to-be-detected gas is monitored through the monitoring module, so that continuous detection of the nuclear waste gas can be realized, and the monitoring risk caused by transfer of the nuclear waste gas is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power plant detection instruments, and in particular relates to a dual gas analysis instrument used in a nuclear power plant. Background Art

[0002] Nuclear power plants produce radioactive gases. In order to prevent these gases from causing radiation risks and hydrogen explosion risks, the gas content needs to be monitored.

[0003] Hydrogen content and oxygen content are common monitoring requirements. The monitoring method has always been to collect gas on-site and then transfer it to the laboratory for monitoring. However, this method has low monitoring timeliness and poses high industrial safety and radiation protection risks. Summary of the invention

[0004] The purpose of the present invention is to provide a dual gas analysis instrument for a nuclear power plant to continuously monitor nuclear waste gas and reduce monitoring risks.

[0005] The present invention adopts the following technical solution: a dual gas analysis instrument for a nuclear power plant, comprising a control cabinet located in a first area and a sampling test cabinet located in a second area;

[0006] Signal connection between control cabinet and sampling test cabinet;

[0007] The sampling test cabinet includes a sampling pipeline and a monitoring module which are connected in sequence; the monitoring module includes an oxygen monitoring module and a hydrogen monitoring module;

[0008] The monitoring module is also connected with a purge pipeline and a calibration pipeline.

[0009] Further, the oxygen monitoring module includes two sub-monitoring modules connected in parallel;

[0010] Each sub-monitoring module includes an oxygen inlet pipeline connected to the sampling pipeline, and a flow meter and a control valve are sequentially arranged on the oxygen inlet pipeline along the gas flow direction;

[0011] The other end of the oxygen inlet pipeline is connected to the inlet of the oxygen measuring chamber, the outlet of the oxygen measuring chamber is connected to the oxygen outlet pipeline, and the other end of the oxygen outlet pipeline is connected to one end of the hydrogen inlet pipeline of the hydrogen monitoring module; a control valve is installed on the oxygen outlet pipeline.

[0012] Further, the other end of the hydrogen inlet pipeline is connected to the inlet of the hydrogen measurement chamber, and the outlet of the hydrogen measurement chamber is connected to the sampling gas outlet through the outlet pipeline;

[0013] A control valve is installed on the hydrogen inlet pipeline;

[0014] A control valve, a one-way valve, a pressure sensor and an outlet valve are installed in sequence along the gas flow direction on the hydrogen outlet pipeline.

[0015] Further, the sampling pipeline includes a condenser, and the inlet of the condenser is connected to the sampling gas inlet;

[0016] The outlet pipeline of the condenser tank is connected to the buffer tank through a parallel sampling pipeline;

[0017] The outlet pipeline of the buffer tank is connected to the oxygen inlet pipeline of each sub-monitoring module;

[0018] Among them, a pressure regulating valve and a flow meter are installed in sequence on the outlet pipeline of the condensation tank along the gas flow direction; and a pressure regulating valve is installed on the outlet pipeline of the buffer tank.

[0019] Furthermore, a control valve, a sampling pump, a control valve and a one-way valve are sequentially installed on each sampling sample pipeline along the gas flow direction.

[0020] Furthermore, a direct bypass is provided between the outlet pipeline of the buffer tank and the outlet valve;

[0021] A control valve and a check valve are installed on the bypass.

[0022] Further, the purge pipeline includes a purge main pipe, and the purge main pipe is respectively connected to the two oxygen measurement chambers and the hydrogen measurement chamber;

[0023] The two oxygen measuring chambers and the hydrogen measuring chamber are connected to the calibration gas outlet through the calibration gas outlet pipe.

[0024] Further, the calibration pipeline includes a calibration gas inlet pipe connected to the outlet pipeline of the condenser;

[0025] The calibration gas inlet pipe is connected to the outlet pipe of the condenser and is passed between the flow meter and the pressure regulating valve.

[0026] Furthermore, the condensation tank and the buffer tank are both connected to the calibration gas outlet pipe.

[0027] Furthermore, the pipeline between the pressure sensor and the outlet valve on the hydrogen outlet pipeline is connected to the calibration gas outlet pipe.

[0028] The beneficial effects of the present invention are as follows: the present invention connects the sampling test cabinet with the nuclear waste gas pipeline, continuously samples therefrom through the sampling pipeline, and then monitors the hydrogen and oxygen content in the gas to be tested through the monitoring module, thereby achieving continuous detection of nuclear waste gas, thereby avoiding monitoring risks caused by the transfer of nuclear waste gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of a dual gas analysis instrument for a nuclear power plant according to an embodiment of the present invention;

[0030] Figure 2 This is a first flow chart of a dual gas analysis instrument according to an embodiment of the present invention;

[0031] Figure 3 This is a second flow chart of the dual gas analysis instrument according to an embodiment of the present invention.

[0032] Among them: 100. Control cabinet; 200. Sampling and measuring cabinet; 300. Oxygen monitoring module; 400. Hydrogen monitoring module. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] The dual gas analyzer mainly realizes the continuous monitoring and analysis of the gas content of oxygen and hydrogen in the pipeline, and sends out an alarm signal when the hydrogen and oxygen content exceeds the limit. Therefore, the oxygen sensor and pretreatment circuit, hydrogen sensor and its pretreatment circuit are the key to the entire system. To formulate a plan, it is necessary to first select the sensor and design a suitable system sampling and pretreatment circuit according to the characteristics of the sensor. The following is based on these two parts to carry out technical route analysis.

[0035] Specifically, the present invention discloses a dual gas analysis instrument for a nuclear power plant, such as Figure 1 As shown, it includes a control cabinet 100 located in the first area and a sampling test cabinet 200 located in the second area; the control cabinet 100 and the sampling test cabinet 200 are signal connected; the sampling test cabinet 200 includes a sampling pipeline and a monitoring module connected in sequence; the monitoring module includes an oxygen monitoring module 300 and a hydrogen monitoring module 400; wherein, the monitoring module is also connected to a purge pipeline and a calibration pipeline.

[0036] The present invention connects the sampling test cabinet with the nuclear waste gas pipeline, continuously samples from it through the sampling pipeline, and then monitors the hydrogen and oxygen content in the gas to be tested through the monitoring module, so as to achieve continuous detection of nuclear waste gas, thereby avoiding the monitoring risk caused by the transfer of nuclear waste gas. Among them, the first area is the green area (≤0.01mSv / h), and the second area is the yellow area (≤1mSv / h). The sampling and measuring cabinet is responsible for the measurement and remote transmission of the sample gas, and the control cabinet is responsible for the display of the sample gas concentration, the display and remote transmission of fault and alarm signals.

[0037] In the present invention, the oxygen monitoring module 300 includes two parallel monitoring modules. Figure 2 and Figure 3 As shown, each sub-monitoring module includes an oxygen inlet pipeline connected to the sampling pipeline, and a flow meter and a control valve are sequentially arranged on the oxygen inlet pipeline along the gas flow direction; the other end of the oxygen inlet pipeline is connected to the inlet of the oxygen measuring chamber, the outlet of the oxygen measuring chamber is connected to the oxygen outlet pipeline, and the other end of the oxygen outlet pipeline is connected to one end of the hydrogen inlet pipeline of the hydrogen monitoring module; a control valve is installed on the oxygen outlet pipeline.

[0038] By adopting two sub-monitoring modules, the oxygen content measured by the two sub-monitoring modules can be effectively utilized, thereby improving the accuracy of the monitoring results.

[0039] Regarding the selection of oxygen sensors, the commonly used technical principles of oxygen sensors include paramagnetic, zirconia, electrochemical, coordinated laser absorption spectroscopy, etc. The paramagnetic type is not suitable for the tilting and shaking environment of the dual gas analyzer prototype due to its poor vibration resistance; the zirconia method cannot meet the accuracy requirements of the dual gas analyzer prototype due to its poor quantitative accuracy. Therefore, the present invention mainly analyzes the two technical routes of electrochemical method and coordinated laser absorption spectroscopy.

[0040] The principle of electrochemical method is to measure gas composition according to the change of ion quantity or current caused by chemical reaction. This type of sensor consists of a sensing electrode (or working electrode) and a counter electrode, with a thin layer of electrolyte between the two electrodes. The gas to be detected first passes through a small capillary sensor, then diffuses into it through a hydrophobic membrane, and finally reaches the electrode surface. The structural design of the sensor ensures that an appropriate amount of gas will enter and react with the sensing electrode to generate sufficient electrical signals, while preventing the electrolyte from leaking out of the sensor. The gas diffused into the sensor through the hydrophobic membrane undergoes oxidation / reduction reaction at the sensing electrode, and a resistor is connected between the electrodes. In this way, a current proportional to the oxygen concentration will be generated between the cathode and the anode. By detecting this current, the oxygen concentration in the gas is reflected.

[0041] The electrochemical method is relatively mature in nuclear power applications due to its small size, low cost, good repeatability and high linearity. However, due to the consumption of chemical principles, the life of the sensor is relatively short, and the hydrophobic membrane needs to be maintained regularly and the electrode needs to be polished (the maintenance cycle is 2 to 6 months); at the same time, because the chemical electrode is also easily affected by the environment, the detection accuracy and response time are still somewhat behind those of the coordinated laser absorption spectroscopy (TDLAS) method.

[0042] The coordinated laser absorption spectroscopy (TDLAS) method is essentially a semiconductor laser spectral absorption technology, which obtains the concentration of the gas by analyzing the selective absorption of laser by gas molecules. A laser beam of a specific wavelength is used to pass through the gas to be measured. The attenuation of the laser intensity has a certain relationship with the concentration of the gas. The concentration of the gas to be measured can be obtained by analyzing the attenuation information of the laser intensity.

[0043] The principle of its measurement method is based on a tunable diode laser. By controlling the temperature of the laser diode or injecting current, the output laser wavelength can be fine-tuned. In one scanning cycle, the absorption spectrum containing the measured gas information and the background spectrum excluding the measured gas information can be obtained, thereby analyzing the gas concentration. Therefore, TDLAS is a high-resolution spectral absorption technology that can resist the interference of background gas in principle, and the measurement results are highly reliable. It can be used to monitor gas concentration online in various harsh environments such as high temperature, high dust, and high corrosion. It is currently widely used in the field of traditional gas detection and is gradually being tested in the field of nuclear power applications.

[0044] The present invention investigates oxygen sensors of two technical methods and comprehensively compares their main parameters as shown in Table 1 below.

[0045] Table 1 Comparison of engineering indicators of oxygen sensors

[0046]

[0047] In summary, the dual gas analyzer of the present invention selects an oxygen sensor using a tunable laser absorption spectroscopy (TDLAS) method.

[0048] In the present invention, the other end of the hydrogen inlet pipeline is connected to the inlet of the hydrogen measuring chamber, and the outlet of the hydrogen measuring chamber is connected to the sampling gas outlet through the outlet pipeline; a control valve is installed on the hydrogen inlet pipeline; a control valve, a one-way valve, a pressure sensor and an outlet valve are installed in sequence on the hydrogen outlet pipeline along the gas flow direction. In addition, a flow meter is also added in the hydrogen measuring chamber, through which it can be detected whether there is gas circulation, so as to judge whether the sampling and measuring cabinet is operating normally.

[0049] The commonly used technical principles of hydrogen sensors include thermal conductivity, electrochemical method, catalytic combustion, metal oxide semiconductor, tunable laser absorption spectroscopy (TDLAS), etc. The catalytic combustion method is mainly used for high-temperature ambient gases, which is inconsistent with the gas environment of the dual gas analyzer; and the current technology of the metal oxide semiconductor method is difficult to achieve 0-100% range of hydrogen detection; although the tunable laser absorption spectroscopy (TDLAS) method has fast detection speed and high accuracy, it is mainly a laboratory product for hydrogen detection, and there are no large-scale commercial products, which is not suitable for nuclear power where safety and reliability requirements are high; therefore, the following mainly analyzes the electrochemical method and thermal conductivity method.

[0050] The principle of electrochemical hydrogen sensor is similar to that of oxygen sensor, both of which obtain gas concentration by detecting the electrical signal generated by the reaction between the sensor and the measured gas, and the electrical signal is proportional to the gas concentration. Due to the consumption of chemical principles, the life of the electrochemical method sensor is much shorter than that of the thermal conductivity method, and the gas permeation membrane and electrodes of the sensor need to be frequently maintained (2 to 6 months).

[0051] The principle of thermal conductivity method is to realize the concentration of the measured gas by measuring the change of thermal conductivity of the mixed gas. Therefore, it is most suitable for measuring binary gases, such as A or B in A and B mixed gas, and using another gas as background gas. If it is used to measure multiple mixed gases, the influence of other gases must be considered. The components of the gas to be measured by the dual gas analyzer are mainly N2 and H2, and there are also small amounts of O2, radioactive inert gases and water vapor. The thermal conductivity coefficients of these gases are different, as shown in Table 2 below.

[0052] Table 2 Gas thermal conductivity

[0053]

[0054] As can be seen from Table 2 above, the thermal conductivity of O2 in the gas to be tested is comparable to that of the background gas N2, which has little effect on the measurement result of H2. Therefore, the H2 content measured by this technical method is relatively accurate. Moreover, due to its technical characteristics, this method has a wide detection range and is suitable for high-concentration gas detection scenarios.

[0055] Since the basic principle of thermal conductivity sensor is to convert the heat carried away by gas flow, the change of gas flow rate will affect the monitoring. The monitoring accuracy of the sensor can be ensured by using a side-flow diffusion thermal conductivity detection cell.

[0056] The present invention investigates hydrogen sensors of two technical methods and comprehensively compares their main parameters as shown in Table 3 below.

[0057] Table 3 Comparison of hydrogen sensor engineering indicators

[0058]

[0059]

[0060] In summary, the thermal conductivity method of hydrogen sensor is selected.

[0061] In one embodiment, the sampling pipeline includes a condensing tank, the inlet of which is connected to the sampling gas inlet; the outlet pipeline of the condensing tank is connected to the buffer tank through a parallel sampling sub-pipeline; the outlet pipeline of the buffer tank is connected to the oxygen inlet pipeline of each sub-monitoring module; wherein a pressure regulating valve and a flow meter are sequentially installed on the outlet pipeline of the condensing tank along the gas flow direction; and a pressure regulating valve is installed on the outlet pipeline of the buffer tank.

[0062] Preferably, a control valve, a sampling pump, a control valve and a one-way valve are sequentially installed along the gas flow direction on each sampling sample pipeline.

[0063] In addition, a direct bypass is set between the outlet pipe and the outlet valve of the buffer tank; a control valve and a one-way valve are installed on the bypass. Through the setting of the bypass, nuclear waste gas can be discharged when no monitoring is performed or all sensors fail.

[0064] In one implementation of the present invention, the purge pipeline includes a purge main pipe, which is connected to two oxygen measuring chambers and a hydrogen measuring chamber respectively; the two oxygen measuring chambers and the hydrogen measuring chamber are both connected to a calibration gas outlet through a calibration gas outlet pipe.

[0065] The calibration pipeline includes a calibration gas inlet pipe connected to the outlet pipeline of the condenser; wherein the calibration gas inlet pipe is connected to the outlet pipeline of the condenser between the flow meter and the pressure regulating valve on it (referring to the outlet pipeline of the condenser).

[0066] Moreover, the condensation tank and the buffer tank are both connected to the calibration gas outlet pipe. The pipeline between the pressure sensor and the outlet valve on the hydrogen outlet pipeline is connected to the calibration gas outlet pipe. Through such a design, the condensate generated in the pipeline can be discharged.

[0067] like Figure 2 and Figure 3 The following are some of the pipelines of the dual gas analyzer. Due to the size limitation of the drawing, it is divided into two parts for display. The entire system process includes nitrogen purging, instrument calibration, and gas measurement.

[0068] When nitrogen purging is performed:

[0069] Nitrogen enters from the purge gas inlet, valve V20 is opened, and valve V21 is closed. The nitrogen inlet is sent to two oxygen measurement chambers and one hydrogen measurement chamber through pipelines, and at the same time, valves V22 and V23 in front of the two oxygen measurement chambers are opened, and valve V24 in front of the hydrogen measurement chamber is opened.

[0070] The purge gas flowing out of the oxygen measurement chamber and the hydrogen measurement chamber passes through the one-way valve V26, the one-way valve V27 and the one-way valve V29 respectively, enters the calibration gas outlet pipe, and is finally discharged through the calibration gas outlet.

[0071] When calibrating:

[0072] The calibration gas enters from the calibration gas inlet, passes through the one-way valve V28 and the control valve V29, and then enters the two sampling subpipelines through the float flowmeter 1. The control valve V7 is closed. The calibration gas passes through the control valve V3 (V5) in the sampling subpipeline and is pressurized by the sampling pump A (sampling pump B). It then passes through the control valve V4 (V6) and the one-way valve V30 (V31) and enters the buffer tank. The gas is buffered in the buffer tank to ensure the stability of the gas. The gas coming out of the buffer tank passes through the pressure regulating valve V8 and then passes through the float flowmeter 2 and the float flowmeter 3 to enter the two oxygen measurement chambers.

[0073] After the oxygen measurement of the calibration gas is performed, it is discharged through the control valve V10 (V12), the control valve V15 is closed, and the gas flows through the control valve V13 and then enters the hydrogen measurement chamber. After the hydrogen content is measured, it passes through the control valve V14, the one-way valve V18, the pressure sensor and the control valve V34 and is discharged from the calibration gas outlet.

[0074] When measuring nuclear waste gas:

[0075] The nuclear waste gas to be tested enters from the sampling gas inlet, flows through the control valve V1 and enters the condenser. After flowing out of the condenser, it passes through the pressure regulating valve V2 and the float flowmeter 1 and enters the two sampling sample pipes. The subsequent gas flow is the same as the gas flow during the calibration process, until the nuclear waste gas flows out of the hydrogen measuring chamber, passes through the control valve V14, the one-way valve V18, the pressure sensor and the control valve V19 and is discharged from the sampling gas outlet.

[0076] In the above process, since the nuclear waste gas to be tested contains radioactive elements, it must flow strictly according to the predetermined pipeline to avoid leakage. The two sampling sample pipelines can serve as backup for each other, and the flow of the incoming gas can be controlled by the float flowmeter 1 in front of the sampling sample pipeline to ensure the accuracy and safety of monitoring. Since the sampling pump adopts a diaphragm pump, the diaphragm pump can transport fluids and gases with relatively unstable chemical properties. In the processing of hazardous and corrosive materials, the diaphragm pump can completely isolate the material from the outside world. However, the diaphragm pump will cause unstable flow in the pipeline, so a buffer tank is designed to stabilize the flow of nuclear waste gas in the buffer tank, which is conducive to subsequent monitoring.

[0077] In addition, since the sensor monitoring process requires the measured gas to be maintained within a predetermined pressure range, a pressure regulating valve is added to the system, especially at the outlet of the condenser and buffer tank, so that the gas pressure can be controlled from the source.

[0078] Several one-way valves are added to the pipeline system to prevent gas backflow. Several gas bypasses are also added to ensure system safety during system repair or maintenance. A flow meter is added to the hydrogen measurement room to detect whether the pipeline gas is flowing smoothly, so that the hydrogen content can be monitored under the condition of circulation.

[0079] In summary, the dual gas analyzer samples the exhaust gas entering the hydrogen-containing exhaust subsystem of the system and continuously measures the concentration of hydrogen and oxygen in the exhaust gas. The dual gas analyzer should include an integrated panel of the measuring device and an oxygen analyzer and hydrogen analyzer on the panel, as well as supporting sampling equipment, pipelines, valves, instruments and control cabinets.

[0080] The dual gas analyzer has operating status signal feedback and equipment fault alarm function during normal operation and shutdown, and the fault signal needs to be sent to the control cabinet system.

[0081] The operating status of the dual gas analyzer and the measured oxygen and hydrogen concentration values ​​should be displayed remotely or locally in the control cabinet. The measuring equipment is arranged in the hazardous area, and the dual gas analyzer can be stopped in an emergency in the non-hazardous area.

[0082] The sampling device collects the sampled gas from the inlet of the sampling main pipe, and after condensation by the condenser, the sampled gas is sent to the dual gas analyzer. The sampled gas after measurement is returned to the sampling main pipe through the sampling pipeline, and the condensed water is discharged through the valve.

[0083] The sampling and processing device of the dual gas analyzer is arranged on the measurement integrated panel WGS1001CR, and the electrical signal converted from the analyzer is transmitted to the control cabinet WGS1002CR through the junction box.

[0084] The control cabinet should be installed separately from the sampling and processing device. The signal comes from the sampling and processing device, and is processed by the microprocessor to send out the following signal:

[0085] For oxygen analyzers (WGS1001MG / WGS1002MG):

[0086] Analog quantity: 4~20mA, range: 0~5%.

[0087] Switching quantity: 3 pairs of passive normally open contacts 48VDC, 1A, for the following 3 alarms:

[0088] ——High oxygen concentration (≥1.5vol%, can be modified on the control panel);

[0089] ——The oxygen concentration is high (≥3.5 vol%, which can be modified on the control panel);

[0090] --Fault.

[0091] For hydrogen analyzer (WGS1003MG): analog value: 4-20mA, range: 0-100%.

[0092] For the entire installation:

[0093] Switching quantity: 1 pair of active normally closed emergency stop contacts 24VDC, 1A.

[0094] The oxygen analyzer in the dual gas analyzer has a dual sensor redundant design. Two oxygen measuring probes are used to perform sampling and measurement respectively, and the detected oxygen content signal can be sent to the control cabinet through an electrical signal. When the two oxygen measuring probes are arranged on the measuring pipeline, mutual interference is avoided to ensure the accuracy of the measurement. At the same time, if one of the measuring probes fails or is damaged, it can be replaced online without affecting the other measuring probe.

[0095] The hydrogen analyzer in the dual gas analyzer uses a hydrogen measuring probe to perform sampling and measurement, and can send an electrical signal to the control cabinet for the detected hydrogen content signal. When the hydrogen measuring probe is arranged on the measuring pipeline, it is arranged downstream of the oxygen measuring probe to avoid affecting the two oxygen measuring probes.

[0096] The control cabinet needs to isolate and filter the electrical signals sent by the oxygen analyzer and the hydrogen analyzer and then process them by algorithm. The oxygen analyzer adopts a dual sensor redundancy solution. The processing module in the control cabinet needs to analyze the signal of the oxygen sensor itself and diagnose various faults such as signal interruption, out-of-bounds, high noise, and signal slope out-of-tolerance, so as to determine which sensor signal the control system selects as the effective signal.

[0097] An emergency stop button is set on the control cabinet panel. When the emergency stop button is pressed, the analyzer gas sampling work is stopped and a fault signal is reported. The control cabinet can monitor the sampling flow rate. When the sampling flow rate is lower than the set value, a fault signal is issued to remind the operator to check the operation of the sampling pump. The control cabinet should be equipped with a touch panel to set the analyzer parameters and record fault events and system logs.

[0098] The control cabinet has a small size and can be wall-mounted to meet the requirements of vibration and swing environments. The on-site installation method of the gas measurement cabinet can be floor-standing. Wire rope shock absorbers are set at the bottom and rear of the cabinet, and fixed to the ground and wall through the wire rope shock absorbers. The wire rope shock absorber usually consists of two ends and a wire rope in the middle. When vibration occurs, the wire rope will deform, thereby absorbing part of the impact force, and while absorbing the impact force, it can also reduce the amplitude and frequency of vibration. At the same time, the fastening of each component in the cabinet is strengthened, and the pipeline is fastened with a special pipe fixing clamp to adapt to the vibration and swing environment.

[0099] The sampling and measuring cabinet is installed in a hazardous area. The cabinet body itself is not explosion-proof. Three measuring chambers and one transfer box are set on the measuring panel inside the cabinet body. Two oxygen analyzers and one hydrogen analyzer are independently integrated in the three measuring chambers. The explosion-proof mark is Ex iaⅡCT6. The explosion-proof level of the measuring chamber is intrinsically safe (ia). The electric sparks and thermal effects generated by the oxygen and hydrogen analyzers and other equipment inside it during normal operation and failure cannot ignite the explosive gas mixture, and the surface temperature of the equipment does not exceed 85℃. The transfer box integrates wiring terminals, circuit breakers, etc. The explosion-proof mark is Ex dⅡCT6. The explosion-proof level of the transfer box is flameproof (d). The flameproof shell can withstand the internal explosion pressure without damage, and can ensure that the internal flame gas reduces energy when propagating through the gap, which is not enough to ignite the gas outside the shell. The surface temperature of the equipment does not exceed 85℃.

[0100] The main function of the control cabinet is to supply power to the hydrogen and oxygen analyzers and motors and collect the concentration values ​​and gas flow values ​​of the hydrogen and oxygen analyzers. The data collected from the hydrogen and oxygen content analyzers will be processed by algorithms in the control cabinet, and the hydrogen and oxygen concentration values ​​will be transmitted remotely at 4-20mA, and high threshold and high-high threshold alarm signals of oxygen concentration will be provided.

Claims

1. A dual gas analysis instrument for a nuclear power plant, characterized in that: It comprises a control cabinet (100) located in a first area and a sampling test cabinet (200) located in a second area; The control cabinet (100) and the sampling test cabinet (200) are signal-connected; The sampling test cabinet (200) comprises a sampling pipeline and a monitoring module which are connected in sequence; the monitoring module comprises an oxygen monitoring module (300) and a hydrogen monitoring module (400); Wherein, the monitoring module is also connected to a purge pipeline and a calibration pipeline.

2. A dual gas analysis instrument for a nuclear power plant as claimed in claim 1, characterized in that: The oxygen monitoring module (300) comprises two sub-monitoring modules connected in parallel; Each of the sub-monitoring modules comprises an oxygen inlet pipeline connected to the sampling pipeline, and a flow meter and a control valve are sequentially arranged on the oxygen inlet pipeline along the gas flow direction; The other end of the oxygen inlet pipeline is connected to the inlet of the oxygen measuring chamber, the outlet of the oxygen measuring chamber is connected to the oxygen outlet pipeline, and the other end of the oxygen outlet pipeline is connected to one end of the hydrogen inlet pipeline of the hydrogen monitoring module; a control valve is installed on the oxygen outlet pipeline.

3. A dual gas analysis instrument for a nuclear power plant as claimed in claim 2, characterized in that: The other end of the hydrogen inlet pipeline is connected to the inlet of the hydrogen measurement chamber, and the outlet of the hydrogen measurement chamber is connected to the sampling gas outlet through the outlet pipeline; A control valve is installed on the hydrogen inlet pipeline; A control valve, a one-way valve, a pressure sensor and an outlet valve are sequentially installed along the gas flow direction of the hydrogen outlet pipeline.

4. A dual gas analysis instrument for a nuclear power plant as claimed in claim 2 or 3, characterized in that: The sampling pipeline comprises a condensation tank, and the inlet of the condensation tank is connected to the sampling gas inlet; The outlet pipeline of the condensing tank is connected to the buffer tank through a parallel sampling subpipeline; The outlet pipeline of the buffer tank is connected to the oxygen inlet pipeline of each of the sub-monitoring modules; Among them, a pressure regulating valve and a flow meter are installed in sequence on the outlet pipeline of the condensation tank along the gas flow direction; and a pressure regulating valve is installed on the outlet pipeline of the buffer tank.

5. A dual gas analysis instrument for a nuclear power plant as claimed in claim 4, characterized in that: A control valve, a sampling pump, a control valve and a one-way valve are sequentially installed on each of the sampling subpipelines along the gas flow direction.

6. A dual gas analysis instrument for a nuclear power plant as claimed in claim 4, characterized in that: A direct bypass is provided between the outlet pipeline of the buffer tank and the outlet valve; A control valve and a one-way valve are installed on the bypass.

7. A dual gas analysis instrument for a nuclear power plant as claimed in claim 4, characterized in that: The purge pipeline includes a purge main pipe, and the purge main pipe is respectively connected to the two oxygen measurement chambers and the hydrogen measurement chamber; The two oxygen measuring chambers and the hydrogen measuring chamber are connected to the calibration gas outlet through the calibration gas outlet pipe.

8. A dual gas analysis instrument for a nuclear power plant as claimed in claim 4, 6 or 7, characterized in that: The calibration pipeline includes a calibration gas inlet pipe connected to the outlet pipeline of the condenser; Wherein, the calibration gas inlet pipe and the outlet pipeline of the condensation tank are connected between the flow meter and the pressure regulating valve thereon.

9. A dual gas analysis instrument for a nuclear power plant as claimed in claim 7, characterized in that: The condensation tank and the buffer tank are both connected to the calibration gas outlet pipe.

10. A dual gas analysis instrument for a nuclear power plant as claimed in claim 7, characterized in that: The pipeline between the pressure sensor and the outlet valve on the hydrogen outlet pipeline is connected to the calibration gas outlet pipe.

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