Method for sampling and detecting concentration of hydrogen and oxygen in nuclear power plant primary loop related container

Abstract

The invention belongs to the technical field of gas oxyhydrogen concentration detection in nuclear power plant primary loop related containers, and particularly relates to a sampling detection method for gas oxyhydrogen concentration in nuclear power plant primary loop related containers. The in-container gas component confirmation module is used for confirming the current working state of a container which is about to be subjected to gas sampling to detect the hydrogen and oxygen concentration, so as to confirm the main components of gas in the container; the in-container gas sampling module adopts different sampling exhaust paths according to different components of the gas in the container after confirming the main components of the gas in the container; and the in-container gas detection module is used for detecting hydrogen and oxygen concentrations of gas in the container by using an instrument. Risks of internal irradiation, large deviation of measurement results, hydrogen-oxygen mixed explosion, violation of laws and regulations caused by radioactive gas pollution diffusion and the like due to the fact that personnel inhale radioactive waste gas by mistake in a gas sampling and monitoring process in a container are avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of gas hydrogen and oxygen concentration detection in a container related to a primary circuit of a nuclear power plant, and in particular relates to a method for sampling and detecting gas hydrogen and oxygen concentration in a container related to a primary circuit of a nuclear power plant. Background Art

[0002] In the power operation mode of the M310 nuclear power unit, hydrogen needs to be added to the primary loop system to suppress the irradiation decomposition of water to produce oxidants; and the unit will inevitably produce radioactive gases during normal operation, which will eventually lead to the presence of radioactive hydrogen-containing gases in some containers associated with the primary loop system; in order to avoid the risk of explosion of containers with radioactive hydrogen-containing gases due to hydrogen-oxygen mixture, it is necessary to regularly sample and detect the hydrogen and oxygen concentrations in such containers, and intervene in time when the hydrogen and oxygen concentrations in the gas in the container exceed the limit requirements. Secondly, when the unit is overhauled or a container needs to be repaired, the gas composition in the container will change, from the main component of radioactive hydrogen-containing gas to nitrogen, air, etc. As the main gas composition in the container changes, the sampling and detection method also needs to change accordingly.

[0003] However, the gas sampling and detection diagram in the original design container of the unit is as follows Figure 3 As shown, the gas in the container to be tested is introduced into the dedicated fume hood for gas sampling through a sampling pipeline, and a metal hose is used to connect the outlet of the container sampling pipeline to the inlet of the gas sampling steel bomb, and the outlet of the gas sampling steel bomb is connected to the pipeline leading to the chimney in the fume hood, and finally the gas in the container is discharged to the atmosphere through the chimney; when sampling the gas sample, a sample is extracted from the gas sampling steel bomb using a sampling syringe, and then the syringe is transferred to the laboratory to use a gas chromatograph to analyze the hydrogen and oxygen concentration. The main problems of this design sampling detection method are as follows:

[0004] During the sample transfer process using a syringe, radioactive gas may leak from the syringe, causing people to accidentally inhale radioactive gas, resulting in internal exposure to people and large deviations in test results; during the sampling process of hydrogen-containing radioactive gas, the exhaust gas is directly discharged into the oxygen-containing chimney, which may pose a risk of hydrogen-oxygen mixture explosion; the chimney is equipped with a radiation monitoring instrument to monitor the radioactive activity of the gas discharged from the chimney to the environment, to ensure that the radioactive gas emissions meet regulatory requirements; if the radioactive gas activity in the container to be tested is high, the exhaust gas is directly discharged into the chimney during the sampling process, which may cause the radiation monitoring instrument arranged in the chimney to alarm, resulting in abnormal discharge of high-activity exhaust gas into the environment and the spread of radioactive gas pollution, which violates relevant regulations. Summary of the invention

[0005] The purpose of the present invention is to provide a more comprehensive and safe method for sampling and detecting hydrogen and oxygen concentrations in gas in response to the problems existing in the prior art, so as to avoid the risks of personnel accidentally inhaling radioactive waste gas and causing internal irradiation, large deviations in measurement results, hydrogen and oxygen mixture explosions, and the spread of radioactive gas pollution and violation of laws and regulations during the gas sampling and monitoring process in the container.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for sampling and detecting the hydrogen and oxygen concentration of gas in a container related to a primary circuit of a nuclear power plant comprises a gas component confirmation module in the container, a gas sampling module in the container and a gas detection module in the container; the gas component confirmation module in the container is used to confirm the current working state of the container to be sampled for hydrogen and oxygen concentration detection, thereby confirming the main components of the gas in the container; the gas sampling module in the container is used to take different sampling and exhaust paths according to different components of the gas in the container after confirming the main components of the gas in the container; the gas detection module in the container is used to detect the hydrogen and oxygen concentrations of the gas in the container using an instrument.

[0008] The different sampling exhaust paths include directly discharging the sampling exhaust gas to a chimney, and utilizing a hydrogen-containing radioactive gas receiving buffer box and its matching sampling pipeline as another exhaust path option.

[0009] The hydrogen-containing radioactive gas receiving buffer box is used to receive hydrogen-containing radioactive gas. The buffer box is used as an exhaust path when the main gas component of the container to be detected contains hydrogen and the radioactive gas is sampled.

[0010] The exhaust path is discharged to the chimney and is used for exhausting the gas when the main gas components in the container to be tested are other gases except hydrogen and radioactive gas during sampling and testing.

[0011] The beneficial effects achieved by the present invention are:

[0012] 1. By adding a new exhaust path for sampling gas in the container to be tested, and taking different exhaust paths according to the different working states of the container to be tested, when the gas component in the container is hydrogen-containing radioactive gas, the exhaust path is discharged to the hydrogen-containing radioactive waste gas receiving buffer box, and when the other components are sampled and tested, the exhaust path is discharged to the chimney; thereby avoiding the risk of hydrogen-containing radioactive gas being directly discharged to the chimney, which may cause hydrogen-oxygen mixed explosion and radioactive gas pollution diffusion and violate regulations.

[0013] 2. A new portable hydrogen and oxygen detection device has been added. When the gas pressure in the container to be detected is too low to establish the sampling flow through the pressure difference, the vacuum pump installed in the device can be started to force the establishment of the sampling flow, thus solving the problem that the sampling flow cannot be established by the pressure difference due to the low gas pressure in the container to be detected.

[0014] 3. By adding a portable hydrogen and oxygen analysis device, the hydrogen and oxygen concentrations in the gas in the container can be directly detected and analyzed, solving the problem of internal exposure to personnel and large deviations in test results due to accidental inhalation of radioactive gas caused by radioactive gas leakage during the process of sampling and transferring samples using a sampling syringe. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of a method for sampling and detecting the concentration of hydrogen and oxygen in gases in a related container of a circuit;

[0016] Figure 2 This is a schematic diagram of sampling and testing the concentration of hydrogen and oxygen in the gas in the relevant containers of the primary circuit;

[0017] Figure 2 Among them, 1-7, valve; 8, three-way valve; 9-13, quick connector; 14-16, metal hose; 17, vacuum pump; 18, pressure gauge; 19-20, flow meter; 21, oxygen concentration analyzer; 22, hydrogen concentration analyzer;

[0018] Figure 3 This is a schematic diagram of gas sampling and detection in the original design container of the unit. DETAILED DESCRIPTION

[0019] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] A method for sampling and detecting the hydrogen and oxygen concentration of gas in a container related to a primary circuit of a nuclear power plant comprises a gas component confirmation module in the container, a gas sampling module in the container, and a gas detection module in the container.

[0021] The gas composition confirmation module in the container is used to confirm the current working state of the container that is about to perform gas sampling to detect hydrogen and oxygen concentrations, thereby confirming the main components of the gas in the container.

[0022] The gas sampling module in the container takes different sampling and exhaust paths according to different components of the gas in the container after confirming the main components of the gas in the container.

[0023] The gas detection module in the container uses an instrument to detect the concentration of hydrogen and oxygen in the gas in the container.

[0024] The different sampling exhaust paths include the original design of directly exhausting the sampling exhaust to the outside of the chimney, and using the hydrogen-containing radioactive gas receiving buffer box and its supporting sampling pipeline as another exhaust path option. Since the hydrogen-containing radioactive gas receiving buffer box is designed to receive hydrogen-containing radioactive gas, the buffer box is used as the exhaust path when the main gas component of the container to be tested contains hydrogen and radioactive gas sampling; the exhaust path to the chimney is mainly used for exhausting when the main gas component of the container to be tested is other gases other than hydrogen and radioactive gas sampling and testing.

[0025] The present invention discloses a method for sampling and detecting the hydrogen and oxygen concentration of gases in containers related to the primary circuit of a nuclear power plant. The method confirms the main components of the gas in the container to be detected, and then adopts different sampling and exhaust paths according to different components to detect and analyze the hydrogen and oxygen concentrations of the gas in the container, thereby effectively avoiding the risks of personnel accidentally inhaling radioactive waste gas and causing internal irradiation, large deviations in measurement results, hydrogen and oxygen mixed explosions, and the spread of radioactive gas pollution and violation of regulations during the gas sampling and monitoring process in the container.

[0026] Verify the working status of the container to be tested. If the container to be tested is a container that normally receives hydrogen-containing radioactive gas or the container is purged with nitrogen before maintenance, the exhaust path when sampling the gas in the container to be tested is discharged to the hydrogen-containing radioactive gas receiving buffer box, connect the quick connector 9 with the quick connector 10 of the metal hose 16, connect the quick connector 11 of the metal hose 16 with the quick connector 12, and open valves 2, 4, 5, and 6. If the container to be tested is a container that performs air purge before maintenance or nitrogen purge after maintenance, the exhaust path when sampling the gas in the container to be tested is discharged to the chimney, connect the quick connector 9 with the quick connector 10 of the metal hose 16, connect the quick connector 11 of the metal hose 16 with the quick connector 13, and open valves 2, 4, 5, and 7. After opening different exhaust paths according to different working conditions of the container to be tested, preferentially turn the three-way valve 8 to direction A, and check whether the flow rates of the flow meters 19 and 20 of the oxygen concentration analyzer 21 and the hydrogen concentration analyzer 22 meet the instrument measurement requirements. If the flow rates of the instrument flow meters 19 and 20 meet the measurement requirements, then read the oxygen concentration analyzer 21 and the hydrogen concentration analyzer 22 for the gas hydrogen and oxygen concentration detection results in the container to be detected; if the flow rates of the instrument flow meters 19 and 20 do not meet the measurement requirements, turn the three-way valve 8 to direction B, open valve 3, start the vacuum pump 17, and adjust the openings of valves 4 and 5 so that the flow rates of the instrument flow meters 19 and 20 meet the measurement requirements, and read the oxygen concentration analyzer 21 and the hydrogen concentration analyzer 22 for the gas hydrogen and oxygen concentration detection results in the container to be detected. After the hydrogen and oxygen concentration detection in the container to be detected is completed, restore the portable hydrogen and oxygen detection device, the relevant valves in the gas sampling fume hood, and the metal hose to their initial states. The hydrogen and oxygen concentration detection work in the container to be detected is completed.

[0027] The key points and intended protection points of the present invention are:

[0028] A new exhaust path is added for sampling and exhausting gas in the container to be tested, and different exhaust paths are adopted according to the different working states of the container to be tested; when the gas components in the container contain hydrogen or radioactive gas, the exhaust path is discharged to the hydrogen-containing radioactive gas receiving buffer box for sampling and testing, and the exhaust path is discharged to the chimney for sampling and testing of other components of gas, so as to avoid the risk of direct exhaust gas discharge to the chimney during sampling and testing of hydrogen or radioactive gas, which may cause hydrogen-oxygen mixture explosion, radioactive gas pollution spread and violate regulations.

[0029] A new portable hydrogen and oxygen detection device has been added. When the gas pressure in the container to be tested is too low to establish the sampling flow through the pressure difference, the vacuum pump installed in the device can be started to force the establishment of the sampling flow. This solves the problem that the sampling flow cannot be established by the pressure difference due to the low gas pressure in the container to be tested.

[0030] The newly added portable hydrogen-oxygen analysis device is equipped with an oxygen analyzer and a hydrogen analyzer, which can directly detect the hydrogen and oxygen concentrations of the gas in the container, thereby solving the problem of leakage during the process of using a sampling syringe to take samples and transfer them to the laboratory, which may cause people to accidentally inhale radioactive waste gas, resulting in internal exposure and large deviations in measurement results.

Claims

1. A method for sampling and detecting the concentration of hydrogen and oxygen in the gas in the primary circuit related container of a nuclear power plant, characterized in that: It includes a gas composition confirmation module in the container, a gas sampling module in the container, and a gas detection module in the container; the gas composition confirmation module in the container is used to confirm the current working state of the container that is about to perform gas sampling and detection of hydrogen and oxygen concentrations, thereby confirming the main components of the gas in the container; the gas sampling module in the container, after confirming the main components of the gas in the container, takes different sampling and exhaust paths according to the different components of the gas in the container; the gas detection module in the container uses an instrument to detect the hydrogen and oxygen concentrations in the gas in the container.

2. The method for sampling and detecting the concentration of hydrogen and oxygen in the gas in the primary circuit related container of a nuclear power plant according to claim 1, characterized in that: The different sampling exhaust paths include directly discharging the sampling exhaust gas to a chimney, and utilizing a hydrogen-containing radioactive gas receiving buffer box and its matching sampling pipeline as another exhaust path option.

3. The method for sampling and detecting the concentration of hydrogen and oxygen in the gas in the primary circuit related container of a nuclear power plant according to claim 2, characterized in that: The hydrogen-containing radioactive gas receiving buffer box is used to receive hydrogen-containing radioactive gas. The buffer box is used as an exhaust path when the main gas component of the container to be detected contains hydrogen and the radioactive gas is sampled.

4. The method for sampling and detecting the concentration of hydrogen and oxygen in the gas in the primary circuit related container of a nuclear power plant according to claim 2, characterized in that: The exhaust path is discharged to the chimney and is used for exhausting the gas when the main gas components in the container to be tested are other gases except hydrogen and radioactive gas during sampling and testing.

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