A ceramic electromagnetic coil for a control rod drive mechanism of a nuclear power plant

Abstract

The present invention relates to a ceramic electromagnetic coil for a control rod driving mechanism of a nuclear power plant, comprising: a ceramic winding frame (01); a coil winding (02): the coil winding (02) is wound in the winding area space of the ceramic winding frame (01); an inorganic packaging layer (03): the inorganic packaging layer (03) is densely filled in the gap between the coil winding (02) and the ceramic coil insulating outer cylinder (04); the ceramic coil insulating outer cylinder (04) is the main insulating layer and protective layer outside the coil; a high temperature resistant lead wire (05): the high temperature resistant lead wire (05) connects the coil winding (02) with a working power supply. Compared with the prior art, the present invention can achieve a temperature resistance level of more than 500°C and a service life of more than 60 years.

Description

Technical Field

[0001] The invention relates to a ceramic electromagnetic coil of a control rod driving mechanism of a nuclear power plant, and relates to the technical field of a control rod driving mechanism of a nuclear reactor in a nuclear power plant. Background Art

[0002] The control rod drive mechanism is the power control system of the nuclear reactor. It is connected to the control rod assembly in the core. By energizing several electromagnetic coils in a certain order, the control rod assembly is inserted and lifted, thereby controlling the average temperature of the core to achieve the purpose of safe reactor startup, reactor power regulation and reactor shutdown. Therefore, the control rod drive mechanism powered by electromagnetic coils is one of the key devices that directly affects the normal operation of the reactor and the safety and reliability of the reactor.

[0003] Due to the temperature transfer of more than 300℃ in the reactor and the resistance heat generated by the electromagnetic coil, the working environment temperature of the electromagnetic coil is as high as 350℃. For a long time, due to the limitations of radiation-resistant and high-temperature-resistant insulation materials and manufacturing processes, the manufacture of electromagnetic coils still requires a large amount of organic materials for bonding, impregnation, and potting, etc., although inorganic materials such as mica, glass fibers, and silicon oxide are used. All organic materials will quickly begin to decompose under high temperature conditions above 300℃. For this reason, on the one hand, a huge fan cooling system is arranged on the top of the reactor, which not only complicates the top structure and occupies precious limited space, but also increases the operating cost and maintenance difficulty. Moreover, once the fan cooling system fails, it may cause the coil to burn out and the reactor to shut down, seriously affecting the safe operation of the nuclear power plant. On the other hand, despite the fan cooling system, the reactor top temperature is still around 150°C. Working at high temperatures for a long time, the organic materials in the electromagnetic coils of the control rod drive mechanism still decompose at a relatively fast rate, causing the coil windings to loosen and the insulation structure to be damaged. The electromagnetic coils need to be replaced regularly, which will greatly affect the reactor's operating safety and the economic efficiency of the power plant's operation. In this regard, since the introduction of the third-generation AP1000 nuclear power technology, the National Nuclear Safety Administration and various design institutes have proposed that the electromagnetic coils should have a service life of 60 years.

[0004] How to make the heat resistance level of electromagnetic coil reach above 300℃ and how to make the service life of electromagnetic coil reach 60 years are two main problems that nuclear power electromagnetic coils have long hoped to solve. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a ceramic electromagnetic coil for a control rod drive mechanism of a nuclear power plant, which can achieve a temperature resistance level of more than 500°C and a service life of more than 60 years, thereby fundamentally solving the problem of limited heat resistance and service life of the electromagnetic coil of the control rod drive mechanism.

[0006] The object of the present invention can be achieved by the following technical solution: A ceramic electromagnetic coil for a control rod drive mechanism of a nuclear power plant, comprising:

[0007] Ceramic winding bobbin;

[0008] Coil winding: The coil winding is wound in the winding area space of the ceramic winding frame; the coil winding is made of high-temperature resistant electromagnetic wire, and the high-temperature resistant electromagnetic wire is wound in the winding area of ​​the ceramic winding frame according to the layers / turns specified in the design. The two ends of the wound coil winding have sufficient lead length to be connected to the high-temperature resistant lead wire.

[0009] Inorganic encapsulation layer: The inorganic encapsulation layer is densely filled in the gap between the coil winding and the insulating outer cylinder of the ceramic coil; the material of the inorganic encapsulation layer is a ceramicizable inorganic powder material, the particle size of the powder material is 1 to 100 nm, including one or more of P2O5, Al2O3, B2O3, ZnO, SiO2, RO, preferably P2O5-Al2O3-B2O3; P2O5-ZnO-B2O3; SiO2-B2O3-ZnO; SiO2-Al2O3-RO, etc.

[0010] Ceramic coil insulation outer cylinder: The ceramic coil insulation outer cylinder is a through-cylindrical shape, serving as the outer insulation structure of the coil, used for external insulation and protection of the coil winding and packaging constraints of inorganic packaging materials. The ceramic coil insulation outer cylinder is a ceramic material cylinder with the same center and thickness as the ceramic winding frame.

[0011] High temperature resistant lead wire: The high temperature resistant lead wire connects the coil winding and the working power supply. The high temperature resistant lead wire is divided into two wires, one is the incoming lead wire and the other is the outgoing lead wire, which are connected to the incoming and outgoing terminals of the winding respectively. After connection, they must be accurately marked with color codes or letters.

[0012] Furthermore, the ceramic winding frame includes: a ceramic winding frame cylinder and end plates a and b arranged perpendicular to it at its upper and lower ends, and the coil winding is wound on the outer side wall of the ceramic winding frame cylinder and located between the end plates a and b.

[0013] The ceramic winding frame cylinder is a hollow cylindrical ceramic cylinder with uniform wall thickness. The end plates a and b are annular, and their inner hole diameters are consistent with the inner diameter of the ceramic winding frame cylinder, and their outer diameters are smaller than the inner diameter of the ceramic coil insulation outer cylinder.

[0014] The end plate a is provided with inlet and outlet wire slots and buried wire slots; the inlet and outlet wire slots are used for the inlet and outlet wires of high-temperature resistant lead wires; the buried wire slot is on the inner side of the end plate a, and the buried wire slot is a cut line from the inlet and outlet wire slots to the ceramic winding skeleton cylinder. The depth of the buried wire slot is the outer diameter value of the high-temperature resistant electromagnetic wire used in the coil winding, and is used to bury the high-temperature resistant electromagnetic wire and guide it to the ceramic winding skeleton cylinder.

[0015] The high temperature resistant electromagnetic wire can withstand high temperatures of 500 to 1000° C., including high temperature resistant ceramic insulated electromagnetic wire, etc., and can be composed of a single strand nickel-plated round copper wire core, a glass fiber sheath, and an inorganic insulating layer.

[0016] The high temperature resistant lead wire can be composed of a wire core composed of multiple strands of nickel-plated round copper wires, an inorganic insulating layer, and a glass fiber braided protective layer.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The ceramic electromagnetic coil adopts an integral ceramic structure consisting of a ceramic winding frame and a ceramic coil insulating outer cylinder. The high insulation, radiation resistance, high temperature resistance and long service life of the ceramic provide the main structural material guarantee for the ceramic electromagnetic coil to reach a temperature resistance level of more than 500°C and a service life of 60 years. The ceramic coil insulating outer cylinder is one of the core inventions of the present invention. In the past, the outer packaging of the electromagnetic coil used in the control rod drive mechanism of a nuclear power plant was either glass ribbon winding and silicone impregnation, or sand filling and silicone pouring and curing. However, when the temperature resistance level of the coil exceeds 300°C, the organic packaging is invalid. The present invention adopts inorganic material packaging, which must solve the problems of demoulding after ceramic packaging and the accuracy, uniformity and crack-free of the outer dimensions of the coil. For this reason, we creatively use the ceramic coil insulating outer cylinder as a structural component as the coil outer packaging body, and the powdered inorganic packaging material becomes an adhesive connecting the coil winding and the ceramic insulating outer cylinder.

[0019] (2) The ceramic electromagnetic coil uses a ceramic inorganic packaging material with a temperature resistance level of more than 600°C as a filler for the gaps between the turns of the coil winding and the gaps between the coil winding and the insulating outer tube of the ceramic coil. After being sintered at a temperature of more than 700°C, it becomes a ceramic body, overcoming the fundamental defect that the previous organic materials cannot withstand high temperatures of more than 300°C. It completely replaces the organic casting materials and potting materials of the existing electromagnetic coils, plays a role in filling the gaps in key materials and processes, and provides packaging material guarantees for the ceramic electromagnetic coil to achieve a temperature resistance level of more than 500°C and a service life of 60 years.

[0020] (3) The ceramic electromagnetic coil uses high-temperature resistant electromagnetic wire insulated by inorganic materials, ensuring that the core of the electromagnetic coil - the coil winding can operate for a long time at a temperature resistance level of more than 500°C and a service life of more than 60 years.

[0021] (4) The ceramic electromagnetic coil uses high temperature resistant lead wires insulated by inorganic materials, so that the coil lead wires can reach the same temperature resistance level as the entire ceramic coil, which is above 500°C, and have a service life of more than 60 years.

[0022] (5) The ceramic electromagnetic coil adopts an integral ceramic skeleton, inorganic high-temperature resistant electromagnetic wire, inorganic high-temperature resistant lead wire, inorganic packaging material and ceramic coil insulating outer tube, forming a whole composed of all inorganic high-temperature resistant materials. It overcomes the fundamental defect that the organic materials such as silicone in the skeleton, casting material and potting material made of inorganic materials such as mica and silica bonded with organic materials in the past coils cannot withstand temperatures above 300°C, and has achieved the ability to withstand temperatures above 500°C. In addition, the material and structural stability of the ceramic electromagnetic coil determine that the service life can reach more than 60 years, which makes the electromagnetic coil of the control rod drive mechanism completely free from the limitations of operating temperature and service life. Even if the top fan cooling system is cancelled, the electromagnetic coil and the drive mechanism can still work normally.

[0023] (6) The ceramic electromagnetic coil of the present invention does not need to change the design of the control rod drive mechanism of the existing nuclear power plant and can directly replace the original electromagnetic coil. It can not only improve the temperature resistance level of the existing control rod drive mechanism, so that the electromagnetic coil and the drive mechanism can still maintain normal operation under the condition of failure of the top fan cooling system, thereby improving the safety guarantee capability of reactor operation; it can also provide technical and device support for optimizing the design of nuclear power plants in the future, eliminating the top fan cooling system, and reducing the size of the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a cross-sectional schematic diagram of a ceramic electromagnetic coil;

[0025] Figure 2 Schematic diagram of the appearance of the ceramic electromagnetic coil;

[0026] Figure 3 It is a schematic diagram of a ceramic winding frame in a ceramic electromagnetic coil;

[0027] Figure 4 A schematic diagram of a ceramic coil insulating outer cylinder in a ceramic electromagnetic coil;

[0028] Figure 5 A top view of the ceramic coil insulation outer cylinder in the ceramic electromagnetic coil. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Unless otherwise specified, the materials used are commercially available.

[0031] Example 1

[0032] Figure 1 : is a schematic cross-sectional view of a ceramic electromagnetic coil, the ceramic electromagnetic coil comprising:

[0033] Ceramic winding frame 01

[0034] Coil winding 02, coil winding 02 is wound in the winding area of ​​the ceramic winding frame 01;

[0035] Inorganic packaging layer 03, the inorganic packaging layer 03 is used to fill the gap between the coil winding 02 and the ceramic coil insulating outer cylinder 04;

[0036] The ceramic coil insulating outer cylinder 04 is a through cylindrical shape, such as Figure 4-5 As shown, it is used as an outer insulating structural member of the coil and serves as an external insulation and protective layer of the coil winding 02;

[0037] High temperature resistant lead wire 05, there are two high temperature resistant lead wires 05, one is the incoming lead wire and the other is the outgoing lead wire, which are used to connect the coil winding 02 and the working power supply.

[0038] In the above structure, the ceramic winding frame 01, the coil winding 02, the inorganic packaging layer 03, and the ceramic coil insulating outer cylinder 04 form a dense and complete ceramic electromagnetic coil structure, which not only ensures that the coil winding 02 can be in a long-term stable working state, but also makes the various parts of the electromagnetic coil densely connected as a whole, forming excellent heat transfer, greatly improving the electromagnetic coil's radiation resistance and high temperature resistance. At the same time, the service life reaches more than 60 years;

[0039] Among them, the ceramic winding skeleton 01 and the ceramic coil insulation outer cylinder 04 are made of industrial ceramics with high density, high strength, low expansion coefficient and good machining performance. This type of material is relatively common and has a wide range of applications; the coil winding 02 is a high-temperature resistant electromagnetic wire, which is composed of a single-strand nickel-plated round copper wire core, a glass fiber winding layer, and an inorganic insulation layer.

[0040] The inorganic packaging layer 03 is made of ceramic inorganic powder material. In this embodiment, P2O5-Al2O3-B2O3 powder is filled in the gap between the coil winding 02 and the ceramic coil insulating outer cylinder 04 to form a dense ceramic body, and then sintered into ceramic at above 700°C. This is the key to the ceramic coil's ability to withstand high temperatures above 500°C. It connects the ceramic winding frame, coil winding, and ceramic coil insulating outer cylinder into one as a ceramic homogeneous material, fundamentally overcoming the defects of existing electromagnetic coils that are cast and encapsulated with organic materials such as silicone.

[0041] Figure 2 This is a schematic diagram of the appearance of a ceramic electromagnetic coil. Figure 1 and Figure 2 As shown, it can be seen that a dense and complete ceramic body is formed by the ceramic winding skeleton 01, the inorganic packaging layer 03, and the ceramic coil insulating outer cylinder 04, which tightly wraps the coil winding 02 in the inner core, so that the radiation resistance and high temperature resistance of the entire electromagnetic coil are equivalent to those of ceramics, which can ensure the normal operation of the control rod drive mechanism of various units in the state of no fan cooling, and fundamentally solve the problem that the organic insulated electromagnetic coil cannot exceed the 300℃ temperature resistance level and 60-year service life; at the same time, the electromagnetic coil reaches a service life of more than 60 years, and it becomes a reality not to replace the control rod drive mechanism electromagnetic coil within the 60-year life of the reactor.

[0042] In the above example, in order to take into account the convenience of wiring and coil transportation, installation and other operations, the high temperature resistant lead wire 05 is composed of a core composed of multiple strands of nickel-plated round copper wire, an inorganic insulation layer, and a glass fiber braided protective layer. The material of the inorganic insulation layer is mainly magnesium oxide. During wiring and coil transportation and installation, the inorganic insulation layer is soft, and it hardens (ceramicized) after being exposed to a high temperature of more than 500°C.

[0043] Figure 3 Schematic diagram of the ceramic winding frame in the ceramic electromagnetic coil, combined with Figure 1 and Figure 3 As shown, the ceramic winding skeleton 01 includes a ceramic winding skeleton cylinder 011, an end plate a012, an end plate b013, an inlet and outlet wire slot 014, and a buried wire slot 015; the ceramic winding skeleton cylinder 011 is a hollow cylindrical ceramic cylinder with an agreed height, diameter, and uniform wall thickness, which serves as the winding bearing body; perpendicular to the two ends of the cylinder are end plates a012 and b013, whose inner hole diameters are consistent with the inner diameter of the ceramic winding skeleton cylinder 011, and whose edge outer diameters are smaller than the inner diameter of the ceramic coil insulating outer cylinder 04, and are used to constrain the width and height of the winding range of the high-temperature resistant electromagnetic wire; the thickness of the end plate a012 is greater than the thickness of the end plate b13; the ceramic winding skeleton cylinder 011 and the ceramic winding The axial space between the skeleton end plate a012 (end plate b013) is the coil winding 02. The ceramic winding skeleton cylinder 011, end plate a012, and end plate b013 are made of the same material and are integrally formed. The inlet and outlet wire slots 014 are located on the ceramic winding skeleton end plate 012 and are used for the entry and exit of the high-temperature resistant lead wire 05. The buried wire slot 015 is on the inner side of the ceramic winding skeleton end plate 012. The buried wire slot 015 is an oblique line from the inlet wire slot 014 to the ceramic winding skeleton cylinder 011. The depth of the buried wire slot 015 is the outer diameter of the high-temperature resistant electromagnetic wire used in the coil winding 02. It is used to bury and guide the high-temperature resistant electromagnetic wire 06 into the ceramic winding skeleton cylinder 011 without affecting the winding arrangement.

[0044] The production process of the ceramic electromagnetic coil is as follows: winding the high-temperature resistant electromagnetic wire in the winding area of ​​the ceramic winding frame 01 according to the number of layers / turns specified in the design, and coating the inorganic powder material 031 layer by layer; leaving enough lead length for the wire ends at both ends of the wound coil winding 02; connecting the lead wires at the wire ends at both ends of the coil winding 02, and marking the incoming and outgoing wires; putting the ceramic coil insulating outer cylinder 04 on the outside of the coil winding 02, placing it on a vibration table and filling it with inorganic powder material 31; putting the filled coil into an oven, and completing the packaging and curing at a high temperature of more than 700°C.

[0045] The obtained ceramic electromagnetic coil is tested according to the conventional testing methods in this industry, and the temperature resistance level can reach above 500°C and the service life can reach above 60 years.

[0046] Example 2

[0047] The inorganic packaging layer 03 fills the gap between the coil winding 02 and the ceramic coil insulating outer cylinder 04 with inorganic material P2O5-ZnO-B2O3 powder, densely filling it into a complete ceramic body, and then sintering it at 700°C connects the ceramic winding frame, coil winding, and ceramic coil insulating outer cylinder into a whole in the form of ceramic homogeneous material, fundamentally overcoming the defects of existing electromagnetic coils cast and encapsulated with organic materials such as silicone.

[0048] The rest is the same as in Example 1.

[0049] Example 3

[0050] The inorganic packaging layer 03 fills the gap between the coil winding 02 and the ceramic coil insulating outer cylinder 04 with inorganic material SiO2-B2O3-ZnO powder, densely filling it into a complete ceramic body, and then sintering it at 700°C, connecting the ceramic winding frame, coil winding, and ceramic coil insulating outer cylinder into a whole in the form of ceramic homogeneous material, fundamentally overcoming the defects of existing electromagnetic coils cast and encapsulated with organic materials such as silicone.

[0051] The rest is the same as in Example 1.

[0052] Example 4

[0053] The inorganic packaging layer 03 inorganic material SiO2-Al2O3-RO powder is filled in the gap between the coil winding 02 and the ceramic coil insulating outer cylinder 04, densely filled into a complete ceramic body, and then sintered at 680°C to connect the ceramic winding frame, coil winding, and ceramic coil insulating outer cylinder into one as a ceramic homogeneous material, fundamentally overcoming the defects of existing electromagnetic coils cast and encapsulated with organic materials such as silicone.

[0054] The rest is the same as in Example 1.

[0055] To sum up, the ceramic electromagnetic coil for the control rod drive mechanism of a nuclear power plant provided by the present invention comprises a ceramic winding skeleton, an inorganic packaging layer, and a ceramic coil insulating outer cylinder to form a dense and complete ceramic body, and the coil winding is tightly wrapped in the inner core, so that the radiation resistance and high temperature resistance of the entire electromagnetic coil are equivalent to those of ceramics, and the normal operation of the control rod drive mechanism of various units in a state without fan cooling can be ensured, fundamentally solving the problem that the organically insulated electromagnetic coil cannot exceed the temperature resistance level of 300°C and the service life of 60 years; at the same time, the electromagnetic coil reaches a service life of more than 60 years, and it becomes a reality not to replace the control rod drive mechanism electromagnetic coil within the 60-year life of the reactor.

[0056] Any improvements or changes made by those skilled in the art based on the above description should fall within the protection scope of the appended claims of the present invention.

Claims

1. A ceramic electromagnetic coil for a control rod drive mechanism of a nuclear power plant, characterized in that: include: Ceramic winding bobbin (01); Coil winding (02): the coil winding (02) is wound in the winding area space of the ceramic winding frame (01); Inorganic packaging layer (03): the inorganic packaging layer (03) is densely filled in the gap between the coil winding (02) and the ceramic coil insulating outer cylinder (04); Ceramic coil insulation outer cylinder (04): the ceramic coil insulation outer cylinder (04) is the outer main insulation layer and protective layer of the coil; High temperature resistant lead wire (05): the high temperature resistant lead wire (05) connects the coil winding (02) and the working power supply; The ceramic coil insulating outer cylinder (04) is a ceramic material cylinder having the same center and thickness as the ceramic winding frame (01); The material of the inorganic encapsulation layer (03) is a ceramicizable inorganic powder material, including one or more of P2O5, Al2O3, B2O3, ZnO, and SiO2; The ceramic coil insulating outer cylinder is the outer packaging body of the coil, and the powdered inorganic packaging material is the adhesive connecting the coil winding and the ceramic insulating outer cylinder; The whole ceramic skeleton, inorganic high temperature resistant electromagnetic wire, inorganic high temperature resistant lead wire, inorganic packaging material and ceramic coil insulation outer cylinder are used to form a whole composed of all inorganic high temperature resistant materials; The coil winding (02) is wound with high temperature resistant electromagnetic wire, which is wound in the winding area of ​​the ceramic winding frame (01) according to the number of layers / turns specified in the design. After the winding is completed, the wire ends at both ends are extended and connected to the high temperature resistant lead wire (05); The inorganic high temperature resistant electromagnetic wire is composed of a single strand nickel-plated round copper wire core, a glass fiber sheath and an inorganic insulating layer.

2. The ceramic electromagnetic coil for a control rod drive mechanism of a nuclear power plant according to claim 1, characterized in that: The ceramic coil insulating outer cylinder (04) is in the shape of a through cylinder and serves as an outer insulating structural component of the coil.

3. The ceramic electromagnetic coil for a control rod drive mechanism of a nuclear power plant according to claim 1, characterized in that: The ceramic winding frame (01) comprises: a ceramic winding frame cylinder (011) and end plates a (012) and b (013) arranged at upper and lower ends thereof and perpendicular thereto; the coil winding (02) is wound on the outer wall of the ceramic winding frame cylinder (011) and is located between the end plates a (012) and b (013).

4. The ceramic electromagnetic coil for a control rod drive mechanism of a nuclear power plant according to claim 3, characterized in that: The ceramic winding frame cylinder (011) is a hollow cylindrical ceramic cylinder with uniform wall thickness. The end plate a (012) and the end plate b (013) are in the shape of a ring, and their inner hole diameters are consistent with the inner diameter of the ceramic winding frame cylinder (011), and their outer diameters are smaller than the inner diameter of the ceramic coil insulation outer cylinder (04).

5. The ceramic electromagnetic coil for a control rod drive mechanism of a nuclear power plant according to claim 3, characterized in that: The end plate a (012) is provided with a wire inlet and outlet slot (014) and a wire embedding slot (015).

6. The ceramic electromagnetic coil for a control rod drive mechanism of a nuclear power plant according to claim 5, characterized in that: The inlet and outlet wire notches (014) are used for the inlet and outlet wires of the high temperature resistant lead wires (05).

7. The ceramic electromagnetic coil for a control rod drive mechanism of a nuclear power plant according to claim 5, characterized in that: The buried wire groove (015) is located on the inner side of the end plate a (012). The buried wire groove (015) is a cut line from the wire inlet and outlet groove (014) to the ceramic winding frame cylinder (011). The depth of the buried wire groove (015) is equal to the outer diameter of the high temperature resistant electromagnetic wire used in the coil winding (02).

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