A liquid level gauge for nuclear power liquid metal and a manufacturing method thereof

Abstract

The present invention discloses a liquid level gauge for nuclear power liquid metal and a manufacturing method thereof, which overcomes the problem that the traditional liquid level gauges in the prior art do not meet the usage requirements of special environments such as nuclear power liquid metal and cannot measure the liquid level of nuclear power liquid metal. The liquid level gauge includes: a multi-core cable, an aviation plug, and a measuring device connected in sequence. The measuring device includes an outer sleeve and an electrode installed inside the outer sleeve. The outer sleeve is provided with an electrode hole, and a hollow ceramic ball head is installed at the electrode hole. One end of the electrode is connected to the aviation plug, and the other end of the electrode passes through the inner hole of the ceramic ball head and is insulated and sealed with the ceramic ball head. The problem of measuring the liquid level of nuclear power liquid metal when the nuclear reactor is at a high temperature of 500 °C and a pressure of 4 MPa is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid level measurement in nuclear power plants, and particularly relates to a liquid level gauge for nuclear power liquid metal and a manufacturing method thereof. Background Art

[0002] A nuclear power plant uses a nuclear reactor to replace the boiler of a thermal power plant. Nuclear fuel undergoes a special form of "combustion" in the nuclear reactor to generate heat, converting nuclear energy into thermal energy to heat water and produce steam. Liquid metal is required during the nuclear reaction process. If the liquid level of the liquid metal decreases, a large amount of liquid metal will remain in the pipelines and structural components of the nuclear reaction device, thus bringing safety accidents. Therefore, it is necessary to measure the liquid level of nuclear power liquid metal.

[0003] The existing measurement methods for metal liquid levels are divided into non-contact and contact types, and there are various instruments and meters for liquid level measurement. For example, a contact liquid level gauge is based on the conductivity of liquid metal. The sensing component is inserted into the liquid metal. When the sensing component contacts the metal liquid surface, the circuit is turned on, thereby measuring the liquid level. However, none of them can meet the usage requirements in special environments such as nuclear power liquid metal and cannot measure the liquid level of nuclear power liquid metal. For example, the China National Patent Office published an invention patent named A Contact Liquid Level Gauge for Liquid Metal, Its Preparation Method and Container on March 8, 2022, with the publication number CN114152307A. This invention discloses a base (113) and a probe (114), where the probe (114) forms a long cylindrical shape with a first end and a second end; the first end is fixed on the base (113) and is used to conduct electricity with the first electrode, and the second end extends downward into the container to conduct electricity with the second electrode through liquid metal; at least part of the side surface of the probe (114) has an insulating coating; the service life of the liquid level gauge is increased, and the measurement accuracy of the liquid level gauge is improved. However, it still cannot meet the measurement of liquid metal in nuclear power plants. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problem that traditional liquid level gauges in the prior art do not meet the usage requirements in special environments such as nuclear power liquid metal and cannot measure the liquid level of nuclear power liquid metal, and provide a liquid level gauge for nuclear power liquid metal and a manufacturing method thereof, solving the problem of measuring the liquid level of nuclear power liquid metal when the nuclear reactor is at a high temperature of 500°C and a pressure of 4 MPa.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: A liquid level gauge for nuclear power liquid metal, comprising:

[0006] A multi-core cable, an aviation plug, and a measuring device connected in sequence. The measuring device includes an outer sleeve and an electrode installed inside the outer sleeve. The outer sleeve is provided with electrode holes, and hollow ceramic ball heads are installed at the electrode holes. One end of the electrode is connected to the aviation plug, and the other end of the electrode passes through the inner hole of the ceramic ball head and is insulated and sealed with the ceramic ball head.

[0007] The present invention can achieve the conduction between the electrode and the liquid metal at a high temperature of 500 °C and a pressure of 4 MPa. A ceramic ball head is used as a connecting part at the connection between the electrode and the outer sleeve to achieve insulation between the electrode and the outer sleeve at high temperatures. During measurement, the electrode is conducted with the nuclear power liquid metal, and the signal is transmitted to the multi-core cable through the aviation plug, and then the multi-core cable is used to transmit the signal to the subsequent data processing device, so as to obtain the liquid level data. It meets the use requirements of special environments such as nuclear power liquid metal and can measure the potential of nuclear power liquid metal.

[0008] Preferably, the electrode holes include a first electrode hole installed at the bottom of the outer sleeve and several groups of electrode holes installed on the side of the outer sleeve. A ceramic ball head is installed at each electrode hole, and an electrode is provided at each ceramic ball head.

[0009] That is, the electrode, the ceramic ball head, and the electrode hole are in a one-to-one correspondence relationship. During conduction, the high-density guiding liquid, namely the nuclear power liquid metal, starts from the bottommost electrode and contacts the electrodes on the side of the outer sleeve in sequence until all the electrodes are in conduction contact with the nuclear power liquid metal (medium) in sequence, so as to obtain the liquid level. During insulation, the nuclear power liquid metal (medium) starts to descend from the highest electrode and descends in sequence to separate from the electrodes on the side of the outer sleeve. The electrodes after the liquid level separation recover insulation in a short time; until all the electrodes are separated from the nuclear power liquid metal (medium).

[0010] Preferably, the groups of electrode holes are evenly and spacedly distributed on the outer sleeve. Each group of electrode holes includes several second electrode holes that are spirally, evenly, and spacedly distributed on the side of the outer sleeve. The line connecting every two second electrode holes forms an angle of 60 degrees with the horizontal line.

[0011] Preferably, each group of electrode holes occupies a length of 500, and each group of electrode holes includes 6 second electrode holes. For example, if the outer sleeve is 2500 mm long, every 500 mm is the distribution range of a group of second electrode holes, and each group of electrode holes has 6 second electrode holes, that is, 6 electrodes are provided. The electrode holes in each group of electrode holes are spirally distributed, that is, each group of electrodes is spirally distributed. Compared with the vertically distributed electrodes, the numerical distance between adjacent two electrodes is shortened. That is, for the same vertical distance, more electrodes can be installed, so that the liquid level range that can be measured becomes larger, thereby improving the liquid level measurement accuracy. However, the number of second electrode holes in each group of electrode holes does not necessarily have to be the same.

[0012] Preferably, the spherical surface of the ceramic ball head is smooth. At the end where the electrode passes through the inner hole of the ceramic ball head, its top is spot-welded into a ball head. The smooth glazed ceramic ball head and the part where the top of the electrode contacts the liquid metal are spot-welded into a smooth ball head, enabling the electrode and the liquid metal to conduct quickly; at the same time, it can achieve that the electrode ball head does not hang liquid, thus meeting the requirement of quick insulation and more accurately improving the measurement accuracy.

[0013] Preferably, the electrode includes a stainless steel tube and a stainless steel wire installed inside the stainless steel tube. Magnesium oxide is filled between the stainless steel wire and the stainless steel tube as an insulator. The electrode uses a stainless steel wire as the center and is heated and drawn with magnesium oxide as an insulator and a stainless steel tube to form a single-core armored cable, thereby obtaining the electrode.

[0014] Preferably, the outer sleeve tube, the stainless steel tube, and the stainless steel wire are all made of 316Ti nuclear-grade stainless steel, and the ceramic ball head is made of inorganic substances. To cope with nuclear radiation at a high temperature of 600 degrees Celsius, the metal materials of the measuring device are made of 316Ti nuclear-grade stainless steel, and the non-metal materials are made of inorganic substances, meeting the usage requirements of special environments such as nuclear power liquid metal.

[0015] A method for manufacturing a liquid level gauge for nuclear power liquid metal includes the following steps:

[0016] S1: Manufacture the electrode, the 316Ti nuclear-grade stainless steel outer sleeve tube, and the ceramic ball head;

[0017] S2: Install the electrode and the ceramic ball head on the outer sleeve tube to obtain a complete measuring device;

[0018] S3: Connect the measuring device to an aviation plug, and connect the aviation plug to a multi-core cable to obtain the liquid level gauge.

[0019] The present invention solves the problems of conduction and insulation disconnection between the electrode and the nuclear liquid metal in the nuclear reactor at a high temperature of 500 °C and a pressure of 4 MPa, meets the usage requirements of special environments such as nuclear power liquid metal, and can measure the liquid level of nuclear power liquid metal.

[0020] Preferably, in the step S1, the steps for manufacturing the ceramic ball head are as follows:

[0021] S1.1: Sinter aluminum oxide at 1350 °C for 24 hours to obtain a mushroom spherical surface hollow ceramic part;

[0022] S1.2: Subject the mushroom spherical surface hollow ceramic part obtained in the step S1.1 to high-temperature glaze sintering at 1150 °C to obtain a ceramic bottom-layer glazed ball head;

[0023] S1.3: Sinter the ceramic base glaze ball head obtained in step S1.2 at a high temperature of 900 °C for a second time to obtain a ceramic ball head with a smooth surface glaze, that is, obtain the final ceramic ball head.

[0024] After multiple tests, the ceramic ball head fired under the conditions of this application can achieve a smooth spherical surface glaze of the ceramic ball head without liquid hanging, so as to prevent the liquid hanging of the ceramic ball head from causing failure to insulate quickly in a short time and resulting in reading errors.

[0025] Preferably, step S2 is further expressed as:

[0026] S2.1: Weld the ceramic ball head at the electrode hole on the outer sleeve, and pass one end of the electrode through the inner hole of the ceramic ball head;

[0027] S2.2: Spot-weld the top end of the electrode into a ball head with a diameter of 1.5 mm, and insulate and seal the electrode and the ceramic ball head inorganically;

[0028] S2.3: Repeat steps S2.1 - S2.2 until all electrodes are installed to obtain a complete measuring device.

[0029] Spot-weld the top end of the electrode into a ball head with a diameter of 1.5 mm so that the electrode ball head does not hang liquid, enabling the liquid level to recover insulation in an extremely short time when the liquid level separates from the electrode, improving the measurement accuracy. Moreover, only the ball head at the top end of the electrode protrudes outside the ceramic ball head.

[0030] Preferably, in step S2.2, insulating and sealing the electrode and the ceramic ball head is as follows: sinter at a constant temperature of 800 °C for two hours; at a high temperature of 500 °C, the insulation resistance between the electrode and the outer sleeve is not less than 15 megohms. Sealing the electrode and the ceramic ball head prevents the nuclear power liquid metal from flowing into the inner part of the outer sleeve through the gap between the electrode and the ceramic ball head, thus protecting the liquid level gauge.

[0031] Therefore, the present invention has the following beneficial effects: All stainless steel metals use 316Ti nuclear-grade stainless steel, and the inner part of the sleeve does not contain organic components, meeting the nuclear grade requirements. It can achieve the conduction between the electrode and the nuclear power liquid metal at a high temperature of 500 °C and a pressure of 4 MPa, thereby measuring the liquid level of the nuclear power liquid metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the overall structural schematic diagram of the liquid level gauge in the present invention.

[0033] Figure 2 is the cross-sectional structural schematic diagram of the liquid level gauge in the present invention.

[0034] Figure 3 is the electrode installation structural schematic diagram in the present invention.

[0035] Figure 4 It is a schematic diagram of the electrode structure in the present invention.

[0036] Figure 5 It is a flowchart of the manufacturing method of the liquid level gauge in the present invention.

[0037] Figure 6 It is a structural diagram of a setting of the second electrode hole in the present invention.

[0038] Figure 7 It is another structural diagram of a setting of the second electrode hole in the present invention.

[0039] In the figure: 1. Multi-core cable; 2. Aviation plug; 3. Outer sleeve; 4. Second electrode hole; 5. First electrode hole; 6. Ceramic ball head; 7. Electrode; 8. Stainless steel tube; 9. Stainless steel wire; 10. Magnesium oxide. Specific embodiments

[0040] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0041] Embodiment 1:

[0042] This embodiment is a liquid level gauge for nuclear power liquid metal. As Figure 1 shown, it includes: a multi-core cable 1, an aviation plug 2, and a measuring device connected in sequence. The measuring device includes an outer sleeve 3 and an electrode 7 installed inside the outer sleeve. The bottom of the outer sleeve is provided with a first electrode hole 5, and the side of the outer sleeve is provided with a plurality of electrode hole groups, which are evenly and spaced apart. Each group of electrode hole groups includes a plurality of second electrode holes 4 that are helically, evenly, and spaced apart on the side of the outer sleeve. The connection line between two adjacent electrode holes in each group of electrode holes forms a 60-degree angle with the horizontal line.

[0043] As Figure 2 shown, a hollow ceramic ball head 6 is installed at each of the first electrode hole and each second electrode hole. One end of the electrode is connected to the aviation plug, and the other end passes through the electrode hole; one electrode passes through each hollow ceramic ball head, that is, one electrode passes through each of the first electrode hole and each second electrode hole. The distribution of the electrode holes is the distribution of the electrode tips on the outer sleeve; there is a one-to-one correspondence between the electrode holes, the electrodes, and the ceramic ball heads.

[0044] As Figure 3 shown, the other end of the electrode passes through the hollow ceramic ball head. The spherical glaze surface of the ceramic ball head is smooth. The tip of the electrode is spot-welded into a 1.5-mm ball head, so that the electrode ball head does not hang liquid, and only the tip ball head of the other end of the electrode protrudes from the ceramic ball head.

[0045] Through the spiral installation method of the second electrode holes, more electrodes can be installed at the same vertical distance. For example, when the electrode diameter is 1.0 mm - 1.2 mm, the ceramic ball head is welded to the outer sleeve, and the diameter occupied by the welding is about 4.0 mm. If electrodes are to be installed on a 12-mm-long outer sleeve, even if two adjacent electrodes are closely installed in the vertical direction of the outer sleeve, at most 3 electrodes can be installed. If the electrodes are installed on the outer sleeve in a spiral shape, in the vertical direction, there is an overlapping part at the electrode installation positions. However, due to the spiral shape, the adjacent electrodes are staggered from each other and do not overlap, so that more electrodes can be installed on the 12-mm-long outer sleeve, making the liquid level measurement more accurate and the measurement range larger.

[0046] As Figure 4 shown, the electrode includes a stainless steel tube 8 and a stainless steel wire 9 installed inside the stainless steel tube. The filling inside the stainless steel tube is magnesium oxide 10, and the magnesium oxide also serves as an insulator.

[0047] In this embodiment, the stainless steel tube, the stainless steel wire, and the outer sleeve are all made of 316Ti nuclear-grade stainless steel, and the ceramic ball head is made of inorganic substances, so as to meet the conduction between the electrode and the nuclear power liquid metal at a high temperature of 500 °C and a pressure of 4 MPa.

[0048] During use, the contact part between the ball head at the top of the electrode and the nuclear power liquid metal is used as the measurement point:

[0049] 1. Conduction: The nuclear power liquid metal (high-density conductive fluid) starts from the electrode at the bottommost end of the outer sleeve and contacts other electrodes on the side of the outer sleeve in sequence until all electrodes are in conduction contact with the nuclear power liquid metal (as the medium) in sequence. When conduction occurs, an electrical signal is sent, and the electrical signal is transmitted to the external data processing device through an aviation plug and a multi-core cable, and the liquid level is calculated by the external data processing device.

[0050] 2. Insulation: The nuclear power liquid metal (as the medium) starts to descend from the electrode at the highest point on the side of the outer sleeve and descends to separate from the electrode in sequence. The electrode after the liquid level separates needs to restore insulation within a short time; until all electrodes are separated from the medium, no liquid hangs on the surface of all electrodes, and all electrodes restore insulation.

[0051] This embodiment also provides a method for manufacturing a liquid level gauge for nuclear power liquid metal. As Figure 5 shown, it includes the following steps:

[0052] The first step: Manufacture the electrode, the 316Ti nuclear-grade stainless steel outer sleeve, and the ceramic ball head.

[0053] Manufacture the electrode:

[0054] The electrode uses 316Ti nuclear-grade stainless steel wire with a diameter of 0.3 - 0.7 mm as the center, and is heated and drawn with a 316Ti nuclear-grade stainless steel tube to form a single-core armored cable with a diameter of 1.5 mm. Magnesium oxide is filled inside the stainless steel tube as an insulator.

[0055] Fabricate the stainless steel outer sleeve: Use 316Ti nuclear-grade stainless steel to fabricate a cylindrical outer sleeve, and set a first electrode hole at the bottom of the outer sleeve, and set a second electrode hole on the side of the outer sleeve as needed.

[0056] Fabricate the ceramic ball head:

[0057] The ceramic ball head serves as an insulator between the electrode and the outer sleeve, and is pressed with the high-temperature insulator aluminum oxide. Alumina is sintered at 1350 °C for 24 hours to obtain a mushroom-shaped spherical hollow ceramic part; the sintered mushroom-shaped spherical hollow ceramic part is then subjected to high-temperature glaze sintering at 1150 °C to obtain a ceramic bottom-layer glazed ball head; the ceramic bottom-layer glazed ball head is subjected to secondary high-temperature glaze re-sintering at 900 °C to make the spherical glaze surface of the ceramic part smooth, and a ceramic surface smooth glazed ball head is obtained, that is, the final ceramic ball head.

[0058] Step 2: Install the electrode and the ceramic ball head on the outer sleeve to obtain a measuring device.

[0059] Specific installation process:

[0060] Weld the ceramic ball head at the electrode hole on the outer sleeve, and pass one end of the electrode through the inner hole of the aluminum oxide ceramic ball head; spot-weld the top of the electrode into a ball head with a diameter of 1.5 mm to ensure that the electrode ball head does not hang liquid, and sinter the electrode and the ceramic ball head at 800 °C for two hours with constant temperature high-temperature glaze to achieve insulation and sealing. The insulation between the electrode and the outer sleeve should reach that when the temperature is 500 °C, the insulation resistance between the electrode and the outer sleeve is not less than 15 megohms.

[0061] Step 3: Connect the measuring device to an aviation plug, and connect the aviation plug to a multi-core cable to obtain a liquid level gauge.

[0062] This application is for dealing with nuclear radiation at a high temperature of 500 degrees Celsius. The electrodes are made of nuclear-grade 316Ti stainless steel metal material, and the ceramic ball heads used for insulation between the electrodes and the outer sleeve are made of inorganic substances. To prevent liquid from hanging on the liquid-contact points of the electrodes, the ceramic ball heads are made into smooth spherical surfaces, and the contact points between the tops of the electrodes and the nuclear power liquid metal are made into smooth ball heads. After many tests, to achieve an insulation seal between the electrodes and the outer sleeve that is not less than 15 megohms at a high temperature of 500 degrees Celsius and not less than 20 megohms at 600 degrees Celsius, and due to the inconsistent expansion coefficients of the metal electrodes, insulating ceramics, and metal sleeves, and the requirement of anti-nuclear radiation that must be an inorganic material, the manufacturing method of the ceramic ball heads in this application is adopted to meet the above requirements. At the same time, all electrodes must achieve separated insulation between each other at a high temperature of 600 degrees Celsius inside the outer sleeve.

[0063] Example Two:

[0064] Based on Example One, as Figure 6 shown, the outer sleeve is 2500 in length, and a total of 4 groups of electrode hole groups are set. Each group of electrode hole groups occupies a length of 500. There are no electrode holes (i.e., no electrodes) in the 500-length section of the outer sleeve close to the aviation plug. Each group of electrode hole groups includes 6 second electrode holes, and there is an electrode at each second electrode hole. There is also an electrode at the bottom of the outer sleeve, for a total of 25 electrodes.

[0065] Example Three:

[0066] Based on Example One, as Figure 7 shown, the outer sleeve is 1500 in length, and a total of 2 groups of electrode hole groups are set. Each group of electrode hole groups occupies a length of 500. There are no electrode holes (i.e., no electrodes) in the 500-length section of the outer sleeve close to the aviation plug. Each group of electrode hole groups includes 6 second electrode holes, and there is an electrode at each second electrode hole. There is also an electrode at the bottom of the outer sleeve, for a total of 13 electrodes.

[0067] The liquid level gauge in this application is mainly used to measure the liquid level of nuclear power liquid metal, can achieve the conduction between the electrodes and the nuclear power liquid metal at a high temperature of 500 °C and a pressure of 4 MPa, and can achieve the insulation between each electrode and the cylindrical stainless steel outer sleeve at a high temperature of 500 °C. At the same time, due to nuclear radiation, the metal materials in the stainless steel sleeve and electrode materials all adopt metals that meet the nuclear-grade requirements, and the ceramic ball heads used for insulation between the electrodes and the outer sleeve adopt inorganic materials, and the high-temperature insulating substances inside the electrodes also adopt inorganic materials.

[0068] The above-described embodiments are only a preferred solution of the present invention, and do not impose any form of limitation on the present invention. There are other variations and modifications without exceeding the technical solutions recorded in the claims.

Claims

1. A liquid level gauge for nuclear power liquid metal, characterized in that, Comprising: A multi-core cable, an aviation plug, and a measuring device connected in sequence. The measuring device includes an outer sleeve and an electrode installed inside the outer sleeve. The outer sleeve is provided with electrode holes, and hollow ceramic ball heads are installed at the electrode holes. One end of the electrode is connected to the aviation plug, and the other end of the electrode passes through the inner hole of the ceramic ball head and is insulated and sealed with the ceramic ball head. The ceramic ball head is obtained by sintering aluminum oxide at 1350°C for 24 hours, then sintering at a high temperature of 1150°C with glaze, and finally sintering again at a high temperature of 900°C for a second time with glaze. The electrode and the ceramic ball head are sintered with glaze at a constant temperature of 800°C for two hours to achieve insulation and sealing. All electrodes must be separated and insulated from each other at a high temperature of 600°C inside the outer sleeve.

2. The liquid level gauge for nuclear power liquid metal according to claim 1, characterized in that, The electrode holes include a first electrode hole installed at the bottom of the outer sleeve and several groups of electrode holes installed on the side of the outer sleeve. A ceramic ball head is installed at each electrode hole, and an electrode is provided at each ceramic ball head.

3. The liquid level gauge for nuclear power liquid metal according to claim 2, characterized in that, The groups of electrode holes are evenly and spacedly distributed on the outer sleeve. Each group of electrode holes includes several second electrode holes that are spirally, evenly, and spacedly distributed on the side of the outer sleeve. The line connecting every two second electrode holes forms an angle of 60 degrees with the horizontal line.

4. A liquid level gauge for nuclear power liquid metal according to claim 1 or 2, characterized in that, The spherical glaze surface of the ceramic ball head is smooth. One end of the electrode passing through the inner hole of the ceramic ball head is spot-welded into a ball head at the top.

5. A liquid level gauge for nuclear power liquid metal according to claim 1 or 2 or 3, characterized in that The electrode includes a stainless steel tube and a stainless steel wire installed inside the stainless steel tube. Magnesium oxide is filled between the stainless steel wire and the stainless steel tube as an insulator.

6. A liquid level gauge for nuclear power liquid metal according to claim 5, characterized in that, The outer sleeve, the stainless steel tube, and the stainless steel wire are all made of 316Ti nuclear-grade stainless steel, and the ceramic ball head is made of inorganic substances.

7. A method for manufacturing a liquid level gauge for nuclear power liquid metal, which is applied to a liquid level gauge for nuclear power liquid metal described in any one of claims 1-6, characterized in that, Including the following steps: S1: Fabricate the electrode, the stainless steel outer sleeve, and the ceramic ball head. S2: Install the electrode and the ceramic ball head on the outer sleeve to obtain the measuring device. S3: Connect the measuring device to the aviation plug and connect the aviation plug to the multi-core cable to obtain the liquid level gauge.

8. A method for manufacturing a liquid level gauge for nuclear power liquid metal according to claim 7, characterized in that, In the step S1, the steps for fabricating the ceramic ball head are: S1.1: Sinter aluminum oxide at 1350°C for 24 hours to obtain a hollow ceramic part with a mushroom-shaped spherical surface. S1.2: Sinter the hollow ceramic part with a mushroom-shaped spherical surface obtained in step S1.1 at a high temperature of 1150°C with glaze to obtain a ceramic ball head with a bottom-layer glaze surface. S1.3: Sinter the ceramic ball head with a bottom-layer glaze surface obtained in step S1.2 at a high temperature of 900°C for a second time with glaze to obtain a ceramic ball head with a smooth surface glaze, that is, the final ceramic ball head.

9. A method for manufacturing a liquid level gauge for nuclear power liquid metal according to claim 7 or 8, characterized in that The step S2 is further expressed as: S2.1: Weld the ceramic ball head at the electrode hole on the outer sleeve and pass one end of the electrode through the inner hole of the ceramic ball head. S2.2: Spot-weld the top of the electrode into a ball head with a diameter of 1.5 mm and insulate and seal the electrode and the ceramic ball head. S2.3: Repeat steps S2.1 - S2.2 until all electrodes are installed to obtain a complete measuring device.

10. A method for manufacturing a liquid level gauge for nuclear power liquid metal according to claim 9, characterized in that, In the step S2.2, insulating and sealing the electrode and the ceramic ball head is: sintering with glaze at a constant temperature of 800°C for two hours; at a high temperature of 500°C, the insulation resistance between the electrode and the outer sleeve is not less than 15 megohms.

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