Online detection device and method for oxygen sensor of lead-bismuth reactor

Abstract

The invention discloses an online detection device and method for a lead-bismuth reactor oxygen sensor. The online detection device for the lead-bismuth reactor oxygen sensor comprises a lead-bismuth container (10), an electrochemical workstation (20) and a data processing system (30), wherein the lead-bismuth container (10) is filled with liquid lead-bismuth, and an oxygen sensor (40) to be detected is inserted into the lead-bismuth container (10); a reference electrode and a counter electrode of the electrochemical workstation (20) are respectively connected with a reference electrode of the oxygen sensor (40) to be detected, and a sensing electrode and a working electrode of the electrochemical workstation (20) are respectively connected to the liquid lead bismuth through leads (23 and 24). According to the on-line detection device for the oxygen sensor of the lead-bismuth reactor, the running state of the oxygen sensor (40) to be detected is monitored on line through electrochemical impedance spectroscopy according to the response of the oxygen sensor (40) to be detected to alternating voltage applied within a specific frequency range.

Description

Lead-bismuth reactor oxygen sensor online detection device and method Technical Field

[0001] The present invention relates to the technical field of corrosion detection, and in particular to an online detection device and method for a lead-bismuth reactor oxygen sensor. Background Art

[0002] Lead-based fast reactors offer advantages such as high safety, strong fuel value-added capabilities, and the ability to utilize transmutable radionuclides, and thus hold broad potential for development. However, corrosion of lead-based alloy coolants on structural steel remains a key technical challenge that needs to be addressed. Corrosion can cause irreversible damage to structural steel, and the resulting metal oxide impurities can clog circuits and core flow channels, causing localized blockages and, in severe cases, endangering reactor safety.

[0003] Corrosion of lead-based alloys on structural materials can be prevented by producing and maintaining a protective oxide film on the stainless steel surface. The correct formation of the oxide film depends on the precise measurement and control of oxygen concentration. Oxygen sensors made from solid electrolytes have been well-established for measuring oxygen concentration in liquid metals. When using oxygen sensors for long-term monitoring, they often exhibit time drift, where the output voltage shifts with age, and the measured value differs from the theoretical value, leading to inaccurate test results. During the operation of a lead-bismuth reactor, the function of the oxygen sensor must be monitored in real time to ensure the accuracy of the oxygen sensor output signal. Using appropriate methods for online, non-destructive, in-situ, and remote monitoring of the operating status of oxygen sensors in lead-bismuth reactors is an urgent issue that needs to be addressed in controlling oxygen concentration in the coolant of lead-bismuth reactors.

[0004] Currently, oxygen sensor status detection methods are mostly applied to gas oxygen sensors. These methods and devices are not suitable for lead-bismuth reactors. Furthermore, oxygen sensor monitoring in lead-bismuth reactors is primarily achieved by disassembling the oxygen sensor and then calibrating it. This method consumes a long analysis process, cannot achieve online measurement, and is prone to damage to the oxygen sensor during disassembly. Technical issues

[0005] The technical problem to be solved by the present invention is to provide an online detection device and method for a lead-bismuth reactor oxygen sensor. Technical Solutions

[0006] The technical solution adopted by the present invention to solve the technical problem is: to provide an online detection device for a lead-bismuth reactor oxygen sensor, comprising a lead-bismuth container filled with liquid lead-bismuth and for inserting the oxygen sensor to be tested, an electrochemical workstation and a data processing system;

[0007] The reference electrode and the counter electrode of the electrochemical workstation are respectively connected to the reference electrode of the oxygen sensor to be measured, and the sensing electrode and the working electrode of the electrochemical workstation are respectively connected to the liquid lead bismuth through leads;

[0008] The electrochemical workstation applies disturbance signals of sinusoidal alternating voltages or sinusoidal alternating currents of different frequencies to the oxygen sensor to be tested. The oxygen sensor to be tested generates a corresponding response signal based on the received disturbance signal. The data acquisition system and the data processing system of the electrochemical workstation process the response signal to obtain an electrochemical impedance spectrum of the oxygen sensor to be tested.

[0009] Preferably, the oxygen sensor to be tested is a potentiometric oxygen sensor.

[0010] Preferably, the oxygen sensor to be tested is a Pt / Air reference oxygen sensor, an LSM / Air reference oxygen sensor, an LSCF / Air reference oxygen sensor, a Bi / Bi2O3 reference oxygen sensor or a Cu / Cu2O reference oxygen sensor.

[0011] Preferably, the lead-bismuth reactor oxygen sensor online detection device also includes an electrode connector, which is arranged on the lead-bismuth container, and the leads of the sensing electrode and the working electrode of the electrochemical workstation are respectively connected to the electrode connector, and the liquid lead-bismuth is connected through the electrode connector.

[0012] Preferably, the lead-bismuth reactor oxygen sensor online detection device further includes a thermocouple; the thermocouple is inserted into the liquid lead-bismuth and close to the oxygen sensor to be tested, and is used to detect temperature changes near the oxygen sensor to be tested.

[0013] The present invention also provides an online detection method for a lead-bismuth reactor oxygen sensor, comprising the following steps:

[0014] S1. Insert the oxygen sensor to be tested into a lead-bismuth container filled with liquid lead-bismuth, connect the reference electrode of the oxygen sensor to be tested to the reference electrode and counter electrode of the electrochemical workstation, and connect the sensing electrode and working electrode of the electrochemical workstation to the liquid lead-bismuth through leads respectively;

[0015] S2. The electrochemical workstation applies a disturbance signal of a sinusoidal alternating voltage or a sinusoidal alternating current of different frequencies to the oxygen sensor to be tested;

[0016] S3, the oxygen sensor to be tested generates a corresponding response signal according to the received disturbance signal and sends the response signal to the electrochemical workstation;

[0017] S4. The data acquisition system and the data processing system of the electrochemical workstation process the response signal to obtain an electrochemical impedance spectrum of the oxygen sensor to be tested.

[0018] Preferably, the oxygen sensor to be tested is a potentiometric oxygen sensor.

[0019] Preferably, the oxygen sensor to be tested is a Pt / Air reference oxygen sensor, an LSM / Air reference oxygen sensor, an LSCF / Air reference oxygen sensor, a Bi / Bi2O3 reference oxygen sensor or a Cu / Cu2O reference oxygen sensor.

[0020] Preferably, in step S2, the sinusoidal alternating current applied in step 2 is lower than 100 mA, and the sinusoidal alternating voltage is lower than 100 mV; and the frequency is 1 mHz-10 MHz.

[0021] Preferably, the lead-bismuth reactor oxygen sensor online detection method further comprises the following steps:

[0022] S5. Determine the operating status of the oxygen sensor to be tested by comparing the electrochemical impedance spectra of the oxygen sensor to be tested obtained regularly, and analyze whether the oxygen sensor to be tested has a fault problem. Beneficial effects

[0023] The beneficial effects of the present invention are as follows: by monitoring the operating status of the oxygen sensor under test by electrochemical impedance spectroscopy based on its response to an AC voltage applied within a specific frequency range, the operating status of the oxygen sensor under test can be monitored online, thereby addressing the urgent need for non-destructive, in-situ, and remote online monitoring of the operating status of oxygen sensors in lead-bismuth reactors, which is of great significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0025] FIG1 is a schematic diagram of the connection structure of an online detection device for a lead-bismuth reactor oxygen sensor according to an embodiment of the present invention.

[0026] FIG2 is an electrochemical impedance spectroscopy diagram of the LSCF / Air reference oxygen sensor under different temperature conditions in the present invention.

[0027] FIG3 is an electrochemical impedance spectroscopy diagram of the Cu / Cu2O reference oxygen sensor at different operating times in the present invention. Modes for Carrying Out the Invention

[0028] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0029] As shown in FIG1 , an online detection device for a lead-bismuth reactor oxygen sensor according to an embodiment of the present invention includes a lead-bismuth container 10 , an electrochemical workstation 20 , and a data processing system 30 , and may also include an oxygen sensor 40 to be tested.

[0030] The lead-bismuth container 10 is used to hold liquid lead-bismuth, and the oxygen sensor 40 to be tested is inserted into the liquid lead-bismuth to monitor the dissolved oxygen concentration in the liquid lead-bismuth. The lead-bismuth container 10 containing liquid lead-bismuth can be a pressure vessel, pipeline, or the like in a lead-bismuth reactor, depending on the actual application. The electrochemical workstation 20 is connected to the oxygen sensor 40 to be tested and a data processing system 30. The electrochemical workstation 20 is used to apply a disturbance signal of a sinusoidal alternating voltage or current of varying frequencies to the oxygen sensor 40 to be tested. The oxygen sensor 40 to be tested generates a corresponding response signal based on the received disturbance signal and feeds it back to the data acquisition system of the electrochemical workstation 20. The data processing system 30 processes the response signal received by the electrochemical workstation 20 to obtain an electrochemical impedance spectrum of the oxygen sensor 40 to be tested.

[0031] The data processing system 30 can be integrated into a control terminal, such as a computer or a control cabinet, and can also be used for remote processing and analysis.

[0032] Specifically, in the lead-bismuth container 10, the oxygen sensor 40 to be tested is inserted into the lead-bismuth container 10 with its detection end and immersed in the liquid lead-bismuth, and the connection end of the oxygen sensor to be tested can be positioned on the top cover of the lead-bismuth container 10 and connected to the electrochemical workstation 20.

[0033] In the present invention, the oxygen sensor 40 to be tested is a potentiometric oxygen sensor.

[0034] The oxygen sensor 40 to be tested may further be a Pt / Air reference oxygen sensor, an LSM / Air reference oxygen sensor, an LSCF / Air reference oxygen sensor, a Bi / Bi2O3 reference oxygen sensor, or a Cu / Cu2O reference oxygen sensor, etc.

[0035] The reference electrode and the counter electrode of the electrochemical workstation 20 are connected to the reference electrode of the oxygen sensor 40 to be tested via wires 21 and 22 respectively. The sensing electrode and the working electrode of the electrochemical workstation 20 are connected to the liquid lead bismuth via leads 23 and 24 respectively.

[0036] The sensing electrode and working electrode of the corresponding electrochemical workstation 20 are connected to liquid lead bismuth. The lead-bismuth reactor oxygen sensor online detection device of the present invention may also include an electrode connector 50. The electrode connector 50 is arranged on the lead-bismuth container 10. The leads 23 and 24 of the sensing electrode and working electrode of the electrochemical workstation 20 are respectively connected to the electrode connector, and the liquid lead bismuth is connected through the electrode connector 50.

[0037] When the lead-bismuth reactor oxygen sensor online detection device of the present invention is working, the electrochemical workstation 20 applies disturbance signals of sinusoidal AC voltage or sinusoidal AC current of different frequencies to the oxygen sensor 40 to be tested. The oxygen sensor 40 to be tested generates a corresponding response signal based on the received disturbance signal. The data acquisition system and data processing system 30 of the electrochemical workstation 20 process the response signal to obtain the electrochemical impedance spectrum of the oxygen sensor 40 to be tested.

[0038] In actual lead-bismuth reactor applications, by comparing the electrochemical impedance spectrum of the oxygen sensor 40 to be tested with the electrochemical impedance spectrum during the initial operation of the oxygen sensor, the corresponding operating status of the oxygen sensor 40 to be tested can be determined, faults of the oxygen sensor 40 to be tested can be discovered in a timely manner, and the accuracy of the output signal of the oxygen sensor 40 to be tested can be ensured.

[0039] Furthermore, the lead-bismuth reactor oxygen sensor online detection device of the present invention may also include a thermocouple 60. Thermocouple 60 is inserted into the liquid lead-bismuth and positioned near the oxygen sensor 40 to detect temperature changes near the oxygen sensor 40. Combined with the electrochemical impedance spectroscopy of the oxygen sensor 40, changes in the electrochemical impedance spectroscopy at different temperatures can be analyzed.

[0040] The lead-bismuth reactor oxygen sensor online detection device of the present invention can realize continuous and automatic detection and recording of electrochemical impedance spectrum characteristic parameter data of the oxygen sensor in the lead-bismuth reactor, and judge the operating status of the oxygen sensor according to the changes in the electrochemical impedance spectrum.

[0041] The lead-bismuth reactor oxygen sensor online detection method of the present invention is implemented using the above-mentioned lead-bismuth reactor oxygen sensor online detection device. Referring to Figure 1, in some embodiments, the lead-bismuth reactor oxygen sensor online detection method may include the following steps:

[0042] S1. Insert the oxygen sensor 40 to be tested into the lead-bismuth container 10 filled with liquid lead-bismuth, connect the reference electrode of the oxygen sensor 40 to the reference electrode and the counter electrode of the electrochemical workstation 20, and connect the sensing electrode and the working electrode of the electrochemical workstation 20 to the liquid lead-bismuth through leads 23 and 24, respectively.

[0043] The detection end of the oxygen sensor 40 to be tested is inserted into the lead-bismuth container 10 and immersed in the liquid lead-bismuth. The connection end of the oxygen sensor 40 to be tested is located above the liquid lead-bismuth, specifically on the exterior or top cover of the lead-bismuth container 10. The reference electrode and counter electrode of the electrochemical workstation 20 are connected to the reference electrode on the connection end of the oxygen sensor 40 to be tested via wires 21 and 22, respectively. The sensing electrode and working electrode of the electrochemical workstation 20 are connected to the liquid lead-bismuth via leads 23 and 24, respectively, and an electrode connector 50.

[0044] The oxygen sensor 40 to be tested is a potentiometric oxygen sensor. The oxygen sensor 40 to be tested can further be a Pt / Air reference oxygen sensor, an LSM / Air reference oxygen sensor, an LSCF / Air reference oxygen sensor, a Bi / Bi2O3 reference oxygen sensor, or a Cu / Cu2O reference oxygen sensor.

[0045] S2 . The electrochemical workstation 20 applies disturbance signals of sinusoidal alternating voltage or sinusoidal alternating current of different frequencies to the oxygen sensor 40 to be tested.

[0046] The applied sinusoidal AC current is less than 100 mA, and the sinusoidal AC voltage is less than 100 mV.

[0047] The frequency of the disturbance signal is 1mHz-10MHz.

[0048] S3 . The oxygen sensor 40 to be tested generates a corresponding response signal according to the received disturbance signal and sends the response signal to the data acquisition system of the electrochemical workstation 20 .

[0049] S4 . The data acquisition system and the data processing system 30 of the electrochemical workstation 20 process the response signal to obtain the electrochemical impedance spectrum of the oxygen sensor 40 to be tested.

[0050] The electrochemical impedance spectrum can be represented by Warburg diagram, admittance diagram, capacitance diagram, Nyquist diagram, and Bode diagram, with Nyquist diagram and Bode diagram being preferred.

[0051] While obtaining the electrochemical impedance spectrum, the temperature near the oxygen sensor 40 to be tested can also be detected based on the thermocouple 60 inserted in the liquid lead bismuth. Combined with the electrochemical impedance spectrum of the oxygen sensor 40 to be tested, the changes in the electrochemical impedance spectrum at different temperatures can be analyzed.

[0052] S5. During long-term operation, the electrochemical impedance spectra of the oxygen sensor 40 to be tested are obtained regularly, and the corresponding operating status of the oxygen sensor 40 to be tested is determined by comparing the electrochemical impedance spectra to analyze whether the oxygen sensor 40 to be tested has a fault problem.

[0053] Failures of the oxygen sensor 40 under test primarily include impurity deposits on the sensor surface, sensor rupture, and short circuits, all of which can cause deviations in the oxygen sensor output. When ambient temperature and oxygen concentration are stable, an increase in the impedance of the oxygen sensor 40 under test compared to the initial impedance indicates possible impurity deposits on the sensor's sensitive element. This can weaken the sensor's electrochemical performance and increase oxygen concentration measurement errors. A decrease in the oxygen sensor's impedance may indicate a short circuit or even a rupture.

[0054] Through the above-mentioned online detection method, electrochemical impedance tests are regularly performed on the oxygen sensor to be tested, and the test results are analyzed.

[0055] Taking the LSCF / Air reference oxygen sensor as the oxygen sensor 40 to be tested as an example, FIG2 shows the electrochemical impedance spectrum of the LSCF / Air reference oxygen sensor under different temperature conditions. In the figure, Z' on the X-axis is the real part, and -Z" on the Y-axis is the imaginary part. As shown in FIG2, the higher the temperature, the higher the conductivity of the oxygen sensor's sensitive element, and the smaller the electrochemical impedance spectrum of the oxygen sensor to be tested.

[0056] The Cu / Cu2O reference oxygen sensor is used as an example of the oxygen sensor 40 to be tested: FIG3 is the electrochemical impedance spectrum of the Cu / Cu2O reference oxygen sensor. It can be seen from the figure that after stable operation for 1000 h under the conditions of constant temperature and constant oxygen concentration (saturated oxygen) at 450°C, the electrochemical impedance increases significantly, which will cause the accuracy of the oxygen sensor in measuring oxygen concentration to decrease.

[0057] If there is no obvious change in the electrochemical impedance of the oxygen sensor, it means that the oxygen sensor to be tested is operating normally; if there is a significant change, it means that the oxygen sensor to be tested is operating abnormally and the abnormal oxygen sensor needs to be repaired; after the repair is completed, continue to perform electrochemical impedance testing on the oxygen sensor according to the process to achieve non-destructive, in-situ, remote online monitoring of the operating status of the oxygen sensor.

[0058] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A lead-bismuth reactor oxygen sensor online detection device, characterized in that: It includes a lead-bismuth container filled with liquid lead-bismuth and used for inserting the oxygen sensor to be tested, an electrochemical workstation and a data processing system; The reference electrode and the counter electrode of the electrochemical workstation are respectively connected to the reference electrode of the oxygen sensor to be measured, and the sensing electrode and the working electrode of the electrochemical workstation are respectively connected to the liquid lead bismuth through leads; The electrochemical workstation applies disturbance signals of sinusoidal alternating voltages or sinusoidal alternating currents of different frequencies to the oxygen sensor to be tested. The oxygen sensor to be tested generates a corresponding response signal based on the received disturbance signal. The data acquisition system and the data processing system of the electrochemical workstation process the response signal to obtain an electrochemical impedance spectrum of the oxygen sensor to be tested.

2. The lead-bismuth reactor oxygen sensor online detection device according to claim 1, characterized in that: The oxygen sensor to be tested is a potentiometric oxygen sensor.

3. The lead-bismuth reactor oxygen sensor online detection device according to claim 2, characterized in that: The oxygen sensor to be tested is a Pt / Air reference oxygen sensor, an LSM / Air reference oxygen sensor, an LSCF / Air reference oxygen sensor, a Bi / Bi2O3 reference oxygen sensor or a Cu / Cu2O reference oxygen sensor.

4. The lead-bismuth reactor oxygen sensor online detection device according to claim 1, characterized in that: The lead-bismuth reactor oxygen sensor online detection device also includes an electrode connector, which is arranged on the lead-bismuth container. The leads of the sensing electrode and the working electrode of the electrochemical workstation are respectively connected to the electrode connector, and the liquid lead-bismuth is connected through the electrode connector.

5. The lead-bismuth reactor oxygen sensor online detection device according to any one of claims 1 to 4, characterized in that: The lead-bismuth reactor oxygen sensor online detection device also includes a thermocouple; the thermocouple is inserted into the liquid lead-bismuth and close to the oxygen sensor to be tested, and is used to detect temperature changes near the oxygen sensor to be tested.

6. A lead-bismuth reactor oxygen sensor online detection method, characterized in that: The following steps are involved: S1. Insert the oxygen sensor to be tested into a lead-bismuth container filled with liquid lead-bismuth, connect the reference electrode of the oxygen sensor to be tested to the reference electrode and counter electrode of the electrochemical workstation, and connect the sensing electrode and working electrode of the electrochemical workstation to the liquid lead-bismuth through leads respectively; S2. The electrochemical workstation applies a disturbance signal of a sinusoidal alternating voltage or a sinusoidal alternating current of different frequencies to the oxygen sensor to be tested; S3, the oxygen sensor to be tested generates a corresponding response signal according to the received disturbance signal and sends the response signal to the electrochemical workstation; S4. The data acquisition system and the data processing system of the electrochemical workstation process the response signal to obtain an electrochemical impedance spectrum of the oxygen sensor to be tested.

7. The online detection method for lead-bismuth reactor oxygen sensor according to claim 6, characterized in that: The oxygen sensor to be tested is a potentiometric oxygen sensor.

8. The online detection method for lead-bismuth reactor oxygen sensor according to claim 7, characterized in that: The oxygen sensor to be tested is a Pt / Air reference oxygen sensor, an LSM / Air reference oxygen sensor, an LSCF / Air reference oxygen sensor, a Bi / Bi2O3 reference oxygen sensor or a Cu / Cu2O reference oxygen sensor.

9. The online detection method for lead-bismuth reactor oxygen sensor according to claim 6, characterized in that: In step S2, the applied sinusoidal alternating current is lower than 100 mA, the sinusoidal alternating voltage is lower than 100 mV, and the frequency is 1 mHz-10 MHz.

10. The online detection method for lead-bismuth reactor oxygen sensor according to any one of claims 6 to 9, characterized in that: The lead-bismuth reactor oxygen sensor online detection method further comprises the following steps: S5. Determine the operating status of the oxygen sensor to be tested by comparing the electrochemical impedance spectra of the oxygen sensor to be tested obtained regularly, and analyze whether the oxygen sensor to be tested has a fault problem.

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