JP2010160062A - Sodium leakage detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sodium leakage detection system not only which can be inspected continuously but also where an ionized section can hardly degrade and which can be easily controlled and causes less malfunctions without using any laser or radiation sources. <P>SOLUTION: The sodium leakage detection system which conducts sampling by sucking a gas around an object to be inspected to detect the leakage of sodium from the object includes sampling piping 2 constituting a flow channel for a sampling gas 1, an ion generation chamber 6 located in a side part of the sampling piping 2 to ionize the gas with a discharge device 7, an ion sensor 8 to measure the quantity of ions mixed with the sampling gas 1 and a signal processor 9 to obtain the leakage quantity of sodium from the output of the ion sensor 8. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sodium leakage detection system for early detection of sodium leakage in facilities such as a fast breeder reactor using sodium as a coolant.

  In a facility that handles sodium, leaked sodium needs to be detected early because it damages the equipment in the facility. In order to detect sodium leakage at an early stage, the following devices for detecting a small amount of sodium in a gas have been conventionally known. (I) Sodium ionization detector (SID: Sodium Ionization Detector, Patent Document 1) using an ionization detector that ionizes and detects leaked sodium by filament heated to high temperature, (ii) Fluorescence emitted when irradiated with laser Liquid metal leak detector (LLD: Laser Leak Detector, Patent Document 2) by laser breakdown method to monitor the radiation, and (iii) Radiation using the fact that the amount of gas ionized by radiation changes by aerosol such as sodium An ionization detector (RID: Radioactive Ionization Detector; Patent Document 3).

Japanese Examined Patent Publication No. 3-68331 Japanese Patent No. 3510561 Japanese Examined Patent Publication No. 63-22252

  The SID (i) is ionized with a filament heated to a high temperature in sodium gas, and the ions are collected by the collecting electrode and detected as a current. Therefore, the SID has high sensitivity and quick response. However, when the sodium concentration in the gas increases, there is a problem that the sensitivity of the filament surface is reduced by sodium. Further, since the high temperature filament is used, it is difficult to use in air in terms of durability, and the output is unstable and adjustment is difficult.

  The LLD of (ii) has a feature that only a small amount of sodium can be detected by capturing luminescence according to sodium. Although only sodium can be detected, a laser is used, and from the viewpoint of durability at the site of the device, it is inappropriate to install a device for each piping. When sampling is performed, continuous inspection is performed on all piping. Difficult to do.

  Rid of (iii) uses a small amount of radiation instead of high temperature filament, but instead of ionizing sodium directly, the ions generated by radiation adhere to the aerosol containing sodium, It measures the effect of reducing ions. Since the amount of ion decrease by aerosol is measured rather than ionizing sodium, the radiation source is less affected by sodium. Although it can be installed on site like SID, it requires a radiation source and is not as small as a SID signal, but it has been desired to be improved because the signal amount is small.

  Based on the above, there is a demand for a sodium leakage detection system that can continuously inspect and that is unlikely to cause deterioration of the ionization part, such as SID, and that does not use a laser in the LLD or a radiation source in the RID and has few malfunctions. Yes.

  The present invention has been made to solve the above-described problems, and can be continuously inspected. Further, the ionization portion is hardly deteriorated, and can be easily managed and have few malfunctions without using a laser or a radiation source. It aims at providing a sodium leak detection system.

In order to solve the above problems, the sodium leak detection system of the present invention is a sodium leak detection system for sucking and sampling the gas around the object to be inspected and detecting sodium leak from the object to be inspected.
A sampling pipe that forms a flow path for the sampling gas; an ion generation chamber that is disposed on a side of the sampling pipe and that ionizes the gas by the discharge device; and an ion sensor that measures the amount of ions mixed with the sampling gas; And a signal processing device for obtaining the amount of sodium leakage from the output of the ion sensor.

In addition, another sodium leakage detection system of the present invention is a sodium leakage detection system that sucks and samples the gas around the object to be inspected, and detects sodium leakage from the object to be inspected.
A sampling pipe that forms a flow path for the sampling gas; an ion generation chamber that is arranged on a side of the sampling pipe and that ionizes the gas by the discharge device; and an ion amount of ions mixed with the sampling gas, And a second ion sensor arranged upstream of the first ion sensor, and a signal processing device for obtaining a sodium leakage amount based on a difference between outputs of the two ion sensors.

  According to the present invention, it is possible to realize a sodium leakage detection system that can be continuously inspected and that is less likely to cause deterioration of the ionization unit and that does not use a laser or a radiation source, and that is easy to manage and has few malfunctions.

The figure which shows the structure of the sodium leak detection system which concerns on Embodiment 1 of this invention. The figure which shows the structure of the sodium leak detection system which concerns on Embodiment 2 of this invention. The figure which shows the structure of the sodium leak detection system which concerns on Embodiment 3 of this invention. The figure which shows the structure of the sodium leak detection system which concerns on Embodiment 4 of this invention. The figure which shows the structure of the sodium leak detection system which concerns on Embodiment 5 of this invention. The figure which shows the structure of the other example in the sodium leak detection system which concerns on Embodiment 5 of this invention. The figure which shows the structure of the sodium leak detection system which concerns on Embodiment 6 of this invention. The figure which shows the internal structure and current measurement part of an ion sensor which concern on Embodiment 7 of this invention. The figure which shows the structure of the sodium leak detection system which concerns on Embodiment 8 of this invention. The figure which shows the structure of the other example in the sodium leak detection system which concerns on Embodiment 8 of this invention.

Hereinafter, each embodiment regarding the sodium leak detection system according to the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a sodium leakage detection system according to Embodiment 1 of the present invention.

  In the present embodiment, a sampling pipe 2 for sampling a gas (gas) around an object to be inspected has a gas suction port 3 at one end and a gas discharge port 4 at the other end. An ion generation chamber 6 for ionizing gas by the discharge device 7 is connected to the side of the sampling pipe 2. In the sampling pipe 2, an ion sensor 8 that measures the amount of ions in the gas is arranged in the middle, and a pump 5 that sucks the sampling gas 1 in the gas discharge port 4. The signal processing device 9 controls the discharge device 7 and monitors the signal of the ion sensor 8. The detailed internal configuration of the ion sensor 8 will be described with reference to FIG.

  In the present embodiment configured as described above, the gas around the object to be inspected is sucked from the gas suction port 3 of the sampling gas 1 and mixed with the ions released from the discharge device 7 in the sampling pipe 2. The During mixing, ions generated by the discharge device 7 are adsorbed and reduced by the sodium aerosol according to the amount of sodium aerosol in the sampling gas. As a result, the ion amount changes, but the ion amount is measured by the ion sensor 8. The signal processing device 9 controls the discharge of the discharge device 7 and measures the ion sensor 8, and obtains the amount of sodium leakage from the output signal of the ion sensor 8 that changes according to the amount of sodium aerosol in the sampling gas. . The signal processing device 9 may monitor the control signal of the discharge device 7 and correct the output signal of the ion sensor 8.

  As shown in FIG. 1, the direction in which the ion sensor 8 is viewed from the discharge device 7 is blocked by the upper part of the ion generation chamber 6, and propagation of electromagnetic noise generated by the discharge to the ion sensor 8 is reduced. Is obtained.

As the discharge device 7, small ions (10 ⁻³ μm or less) having a small particle size in which 10 to 30 molecules similar to ions generated from a radiation source are bonded by Coulomb force can be generated. As a result, ions have a high mobility of ions and are easily attached to the aerosol, thereby improving detection sensitivity. Therefore, the sampling pipe 2 and the discharge device 7 are placed close to each other so that the sampling gas 1 and the ions can be quickly mixed by discharge.

  On the other hand, the particle size of the sodium aerosol is 0.5 μm to 30 μm centering on 1 μm, and a filter (not shown) for selecting and passing aerosol having only this particle size is provided in the gas suction port 3 of the sampling pipe 2. Thus, it becomes possible to obtain a sensitivity characteristic that easily reacts only with sodium.

Further, the ion sensor 8 can measure the distance between the electrodes of the ion sensor 8 and the sampling gas 1 so that it can measure from a small ion (10 ⁻³ μm or less) small particle size that is most easily adsorbed by aerosol to a maximum particle size of 1 μm. Depending on the suction flow rate, the voltage applied by the voltage applying means may be adjusted. This makes it possible to selectively measure ions that react best with sodium aerosol.

  At that time, an aerosol decomposing apparatus that shreds the aerosol by discharge or the like at the filter portion of the gas suction port 3 of the sampling pipe 2 and decomposes it into an aerosol having a particle size of 1 μm or less having ion mobility that can be measured by the ion sensor 8 Can be provided. As a result, the aerosol itself can be detected by the ion sensor 8, and the ion current can be increased.

  Moreover, you may adjust so that the ion produced | generated with the discharge device 7 can produce | generate both positive and negative ions. That is, both positive and negative ions can be generated by applying an alternating voltage to the discharge device 7. By doing so, the aerosol is charged to one polarity and becomes the same polarity as the ions, thereby preventing the amount of ions adsorbed from decreasing. Further, since noise from the discharge device 7 is generated according to the voltage application timing (application cycle) to the discharge device 7, the timing for measuring the ion current of the ion sensor 8 is adjusted according to the timing. Thus, it becomes possible to measure a minute ion current without being affected by the noise current.

  Further, a voltage may be intermittently applied to the discharge device 7 in the ion generation chamber 6. The applied voltage may be a positive and negative voltage applied alternately. Using the measurement data of the ion sensor 8 during the time when no ions are generated in the discharge device 7, it can be evaluated as an increasing component of the ion current due to contamination on the surface of the insulating material of the ion sensor 8. By correcting this leakage current component, measurement that is not affected by contamination on the surface of the insulating material can be performed over a long period of time.

  According to this embodiment, the sodium leak detection system which does not use the radiation source which needs management can be implement | achieved by using the discharge device 7 instead of the conventional radiation for ion generation. In addition, the ion generation chamber 6 having the discharge device 7 is provided on the side of the sampling pipe 2, and the generated ions from the discharge device 7 are generated so that ions of both polarities coexist, whereby the amount of change in ions due to the aerosol is generated. Can be secured, and a sodium leakage detection system with good sensitivity can be constructed.

(Embodiment 2)
FIG. 2 is a diagram showing a configuration of a sodium leakage detection system according to Embodiment 2 of the present invention.
In the present embodiment, an electromagnetic shield 10 is provided at the outlet of the ion generation chamber 6 of FIG. The electromagnetic shield 10 has a mesh-like hole that allows ions to pass therethrough but shields electromagnetic waves, and has the same potential as the system body.

  In the present embodiment configured as described above, the electromagnetic wave generated from the discharge device 7 propagates through the sampling pipe 2 and is not directly received by the ion sensor 8.

  According to this embodiment, it is possible to reduce the influence of electromagnetic noise from the discharge device 7 to the ion sensor 8 that measures a minute ion current, and to accurately measure a minute change amount of the ion current due to the aerosol, and has a good sensitivity. A simple sodium leak detection system.

(Embodiment 3)
FIG. 3 is a diagram showing a configuration of a sodium leakage detection system according to Embodiment 3 of the present invention.
In the present embodiment, the vicinity of the gas discharge port 4 of the sampling pipe 2 and the ion generation chamber 6 are connected by the pipe 13 to recirculate the gas. The pipe 13 has, on the gas discharge port 4 side, a fan 12 and an ion filter 14 that adsorbs ions and dust components in the ion discharge airflow 11.

  With this configuration, ions can be quickly supplied to the sampling pipe 2 by sending the ion emission airflow 11 cleaned by the ion filter 14 into the ion generation chamber 6. Moreover, although the piping 13 is connected from the gas discharge port 4 vicinity, according to the performance of the ion filter 14, it is also possible to take in gas directly from the open external air. Furthermore, the ion emission airflow 11 is configured to control the speed of the airflow, and further the temperature and humidity, so that the amount of ions generated by the discharge in the ion generation chamber 6 can be made constant.

  According to the present embodiment, ions generated in the discharge device 7 in the ion generation chamber 6 can be quickly mixed with the sampled aerosol, and the amount of change in ion current due to the aerosol can be ensured. In addition, the influence of the sampling gas 1 can be reduced, the amount of ions generated from the discharge device 7 can be made constant, and a leak detection system in which the output is less likely to fluctuate depending on the conditions of the sampling gas 1 can be constructed.

(Embodiment 4)
FIG. 4 is a diagram showing a configuration of a sodium leakage detection system according to Embodiment 4 of the present invention.
In the present embodiment, a temperature sensor 15 is provided upstream of the ion sensor 8 in the sampling pipe 2 of FIG.

  In such a configuration, the output of the ion sensor 8 can be corrected based on the indication value of the temperature sensor 15. At this time, since the response time of the ion sensor 8 is earlier than that of the temperature sensor 15, a delay time corresponding to the difference in the response time is evaluated in advance, and the delay time is applied to the output of the ion sensor 8 before the temperature sensor. The output of the ion sensor 8 is corrected with the indicated value of 15.

  According to this embodiment, the influence of temperature can be reduced, and ions having ion mobility that is most affected by highly reliable sodium aerosol can be collected, and a sodium leakage detection system with few malfunctions can be realized.

(Embodiment 5)
FIG. 5 is a diagram showing a configuration of a sodium leak detection system according to Embodiment 5 of the present invention, and FIG. 6 is a diagram showing a configuration of another example in the sodium leak detection system according to this embodiment.

  In FIG. 5, the ion sensor 8 is used as a first ion sensor, and a second ion sensor 16 is provided upstream thereof and connected in series. As shown in FIG. 8, both ion sensors have a center electrode and two electrodes that can apply a positive or negative voltage composed of a cylindrical cathode around the center electrode. By applying a voltage to both electrodes, , Collect the ions in the meantime, and measure the current according to the amount of ions. The first ion sensor 8 may have a cylindrical length longer than that of the ion sensor 8 of the first embodiment, and the second ion sensor 16 may have a cylindrical length that is shorter.

  The gas flowing from one end of the cylindrical cathode moves between both electrodes and then exits from the other end of the cylinder. When traversing the applied electrode, a gas with fast ion mobility collects ions at the electrode immediately even if the traversing time is short, but those with slow ion mobility must stay between the electrodes for a long time. Instead of being collected by the electrode, it flows out of the electrode. Therefore, when two ion sensors are arranged, ions having high mobility are collected by the upstream second ion sensor 16, while ion migration that is not collected by the second ion sensor 16 is collected by the first ion sensor 8. Slowly measured components are measured.

  In such a configuration, the signal ratio of the second ion sensor 15 and the first ion sensor 8 is determined by the difference in ion mobility of ions generated in the discharge device 7. By selecting this ratio as a ratio that is easily changed by sodium aerosol, it is possible to reduce the influence of other components such as dust. The signal processing device 9 obtains the amount of sodium leakage based on the difference between the outputs of both ion sensors.

  In FIG. 6, a correction ion sensor 17 is disposed at the outlet of the ion generation chamber 6. In this configuration, fluctuations in the amount of ions generated in the discharge device 7 can be monitored. By correcting the output of the ion sensor 8 with the output of the correction ion sensor 17 and obtaining the amount of sodium leakage, the influence of the performance change of the discharge device 7 can be reduced.

  The example shown in FIG. 5 is also applied in the case where there is the ion emission airflow 11 of FIG. 3 of the third embodiment, and the example shown in FIG. 6 does not have the ion emission airflow 11 of FIG. 1 of the first embodiment. It also applies to cases.

  According to this embodiment, it is possible to collect ions having ion mobility that is most affected by sodium aerosol, and to realize a highly reliable sodium leakage detection system with few malfunctions. In addition, by monitoring the amount of ions generated by the discharge device 7, it is possible to reduce the influence of deterioration of the discharge device 7.

(Embodiment 6)
FIG. 7 is a diagram showing a configuration of a sodium leakage detection system according to Embodiment 6 of the present invention.
In the ion sensor 8, an ion collection electrode 25 is disposed on the central axis of a cylindrical cathode 26, and an insulating material 18 is provided between both electrodes. The insulating material 18 corresponds to the first insulating material 28 and the second insulating material 29 in FIG.

  In this embodiment, in order to reduce deterioration due to dirt attached to the insulating material 18 of the ion sensor 8, a titanium oxide film is applied to the surface, and the surface is irradiated with the light source 18 provided in the vicinity of the ion sensor 8. . The effect of contamination on the surface of the insulating material is reduced by the activation of the titanium oxide film by ultraviolet irradiation. This makes it possible to obtain a stable indication value over a long period of time.

  According to the present embodiment, it becomes possible to prevent performance degradation due to contamination of the insulating material 18 of the ion sensor 8, and ions having ion mobility that is most influenced by highly reliable sodium aerosol can be collected, resulting in malfunction. Fewer sodium leakage detection systems can be realized.

(Embodiment 7)
FIG. 8 is a diagram illustrating an internal configuration and a current measurement unit of an ion sensor according to Embodiment 7 of the present invention.
Inside the ion sensor 8, an ion collection electrode 25 is disposed on the central axis of a cylindrical cathode 26, and a guard electrode 27 is provided between the two electrodes. The ion collecting electrode 25 and the guard electrode 27 are insulated by a first insulating material 28, and the cathode 26 and the guard electrode 27 are insulated by a second insulating material 29. The cathode 26 is a ground electrode connected to the earth 30 as a ground potential. A high voltage is applied to the guard electrode 27 and the ion collection electrode 25 via a high voltage power supply 31. With this high voltage, ions between the ion collection electrode 25 and the cathode 26 are collected, and the current accompanying the collection is measured by the ammeter 32 as an ion current.

  The first insulating material 28 is sandwiched between the guard electrode 27 and the ion collecting electrode 25, and the current flowing between them is measured by an ammeter 32. However, since both electrodes are at the same potential, almost no current flows. Not flowing. Therefore, the current flowing through the ammeter 32 is measured mainly by the first current path 33 and the current due to ions between the ion collection electrode 25 and the cathode 26 is measured.

  On the other hand, the second insulating material 29 is sandwiched between the cathode 26 and the guard electrode 27, both of which are applied with a high voltage by the high voltage power supply 31, and the leakage current flows like the second current path 34, Monitoring is performed by the second ammeter 35.

  In such a configuration, generally, there is almost no voltage between the ion collecting electrode 25 and the guard electrode 27, so there is almost no current due to contamination on the surface of the first insulating material 28, and the ammeter 32 is not affected. However, when the surface of the first insulating material 28 is significantly contaminated for a long time due to contamination in the sampling gas 1, leakage current due to a weak voltage such as a potential difference caused by contact between the ceramic and the metal cannot be ignored.

  In the present embodiment, the increase in leakage current is monitored and the contamination on the ceramic surface is detected, so that the influence on the measurement of ion current can be evaluated. That is, it is considered that the first insulating material 28 is also soiled almost the same as the second insulating material 29. From this, since the contamination of the surface of the first insulating material 28 can be determined from the contamination of the surface of the second insulating material 29, the second current path 34 passing through the second insulating material 29 is monitored by the ammeter 35. By doing so, it becomes possible to detect dirt inside the ion sensor 8.

  According to the present embodiment, the sampling gas 1 can monitor the rate of increase in leakage current due to contamination of the insulating material inside the ion sensor 8 and correct the measured value using the value, thereby providing highly reliable sodium. A leak detection system can be realized.

(Embodiment 8)
In the prior art, there is a laser-type sodium leak detector (hereinafter referred to as “laser-type leak detector”) by a laser breakdown method. This embodiment is a discharge-type sodium leak detection system described in the first to seventh embodiments. When a sodium leak is detected by, check with a laser leak detector.

  FIG. 9 is a diagram illustrating the configuration of the sodium leakage detection system according to the present embodiment, and FIG. 10 is a diagram illustrating the configuration of another example in the sodium leakage detection system according to the present embodiment.

  In FIG. 9, sampling gas is introduced from the sodium pipe to be inspected through the sampling pipe 20 to the sodium leak detection system 21 and the laser type leak detector 22 of the first to seventh embodiments. The sodium leak detection system 21 is connected so as to continuously inspect the sampling pipe 20, but the laser type leak detector 22 samples each pipe to detect leaks by sequentially scanning the sampling pipe 20. To do. Or it is set as the structure which does not draw piping directly but analyzes the sampled gas.

  In such a configuration, when a leak is detected in the sodium leak detection system 21 that performs continuous inspection, the laser leak detector 22 checks for leaks in the pipe where the leak is detected. When leakage is detected in both, the alarm determination device 23 issues an alarm 24. Thereby, while detecting a leak continuously with the sodium leak detection system 21, it confirms that it is a sodium component in the laser type leak detector 22 for the reduction | restoration of the malfunctioning by those other than sodium.

  Further, in the case of intermittent leakage, the gas sampled by the sodium leakage detection system 21 can be analyzed again by the laser leakage detector 22 as shown in FIG.

  According to the present embodiment, a continuous inspection is performed by the discharge-type sodium leak detection system 21, while a detailed analysis is performed by the laser-type leak detector 22, thereby realizing a sodium leak detection system with few malfunctions.

  DESCRIPTION OF SYMBOLS 1 ... Sampling gas, 2 ... Sampling piping, 3 ... Gas suction port, 4 ... Gas discharge port, 5 ... Pump, 6 ... Ion generation chamber, 7 ... Discharge device, 8 ... Ion sensor, 9 ... Signal processing device, 10 ... Electromagnetic shield, 11 ... Ion emission airflow, 12 ... Fan, 13 ... Piping, 14 ... Ion filter, 15 ... Temperature sensor, 16 ... Second ion sensor, 17 ... Ion sensor for correction, 18, 28, 29 ... Insulating material, 19 ... light source, 21 ... sodium leak detection system, 22 ... laser leak detector, 25 ... ion collecting electrode, 26 ... cathode, 27 ... guard electrode.

Claims (14)

In the sodium leak detection system that sucks and samples the gas around the subject to be inspected and detects sodium leakage from the subject to be inspected,
A sampling pipe that forms a flow path for the sampling gas; an ion generation chamber that is disposed on a side of the sampling pipe and that ionizes the gas by the discharge device; and an ion sensor that measures the amount of ions mixed with the sampling gas; A sodium leak detection system comprising: a signal processing device for obtaining a sodium leak amount from an output of the ion sensor.   The sodium leak detection system according to claim 1, wherein the signal processing device monitors a control signal to the discharge device and corrects an output of the ion sensor. 3. The sodium leakage detection system according to claim 1, wherein a voltage is applied to the discharge device so as to generate ions having a particle size of 10 ⁻³ μm or less.   The sodium leak detection system according to any one of claims 1 to 3, wherein a filter for selecting the particle size of aerosol in the sampling gas to 0.5 to 30 µm is provided at a gas suction port of the sampling pipe. .   The sodium leakage detection system according to any one of claims 1 to 4, wherein an aerosol decomposing device is provided at a gas suction port of the sampling pipe to chop the aerosol into particles having a particle diameter of 1 µm or less.   6. The sodium leakage detection system according to claim 1, wherein an AC voltage or an intermittent voltage is applied to the discharge device.   The sodium leak detection system according to any one of claims 1 to 6, wherein a mesh-shaped electromagnetic shield is provided at an outlet of the ion generation chamber.   The sodium leak detection system according to any one of claims 1 to 7, wherein the vicinity of a gas discharge port of the sampling pipe and the ion generation chamber are connected by a pipe to recirculate the gas.   A temperature sensor for measuring the temperature of the sampling gas is installed upstream of the ion sensor in the sampling gas flow path, and the signal processing device outputs the output of the ion sensor delayed according to the response time of the temperature sensor. The sodium leakage detection system according to any one of claims 1 to 8, wherein the sodium leakage detection system is corrected by an output of a temperature sensor. In the sodium leak detection system that sucks and samples the gas around the subject to be inspected and detects sodium leakage from the subject to be inspected,
A sampling pipe that forms a flow path for the sampling gas; an ion generation chamber that is arranged on a side of the sampling pipe and that ionizes the gas by the discharge device; and an ion amount of ions mixed with the sampling gas, And a second ion sensor arranged upstream of the first ion sensor, and a signal processing device for obtaining a sodium leakage amount based on a difference between outputs of the two ion sensors. Leak detection system.   The correction ion sensor is disposed at the outlet of the ion generation chamber, and the signal processing device corrects the output of the ion sensor by the output of the correction ion sensor. Sodium leak detection system described in 1.   The sodium leak detection according to claim 1, wherein a titanium oxide film is formed on a surface of an insulating material in the ion sensor, and a light source for irradiating light on the surface of the insulating material is provided. system. The ion sensor includes an ion collection electrode, a cathode, and a guard electrode that applies the same voltage as the ion collection electrode between the two electrodes, the ion collection electrode and the guard electrode, and the cathode electrode and the guard. An insulating material is placed between the electrodes,
Measure the leakage current between the guard electrode and the cathode,
The sodium leak detection system according to claim 1, wherein the signal processing device corrects a current signal flowing between the ion collection electrode and the cathode by the leak current.   14. A sodium leak detection system, wherein when a sodium leak is detected by the sodium leak detection system according to claim 1, the sodium leak detection system is further confirmed by a laser type sodium leak detector by a laser breakdown method.

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