A laying structure of heating elements of boron heating system in nuclear power plant

Abstract

The present invention relates to the technical field of temperature probe installation of a boron heating system in a nuclear power plant, and specifically discloses a laying structure of heating elements of a boron heating system in a nuclear power plant, wherein a normal loop heating cable is arranged along the axis on the side wall of a process pipeline, and its position is defined as the circumferential 0° position of the process pipeline; a standby loop heating cable is arranged at the circumferential 180° position of the process pipeline; a normal loop temperature switch capillary and a normal loop thermocouple are arranged at the circumferential 90° position of the process pipeline, and a standby loop thermocouple and a standby loop temperature switch capillary are arranged at the circumferential 270° position of the process pipeline. The present invention standardizes the laying of thermocouples, temperature switches and heating cables of a boron heating system in a nuclear power plant, and avoids problems such as inconsistent temperature display between the main control and the local temperature, frequent start and stop of the heating cable, and asynchronous start and stop of the temperature display with the heating cable due to improper installation.

Description

Technical Field

[0001] The invention belongs to the technical field of temperature probe installation of a boron heating system of a nuclear power plant, and in particular relates to a laying structure of a heating element of a boron heating system of a nuclear power plant. Background Art

[0002] The boron heating system provides heating for the pipes and equipment through which the boric acid solution flows in nuclear power plants, to prevent the boric acid solution from clogging the pipes and equipment due to low-temperature crystallization, thereby maintaining the normal circulation of the fluid and ensuring the safe and stable operation of the unit.

[0003] At present, the nuclear power boron heating system has many defects due to the improper installation of some heating components. For example, if the normal loop thermocouple is too close to the heating cable, the main control and local temperature display will be inconsistent; if the temperature switch capillary is too close to the heating cable, the heating cable will start and stop frequently; if the thermocouple and the temperature switch capillary are not in the same position as the heating cable, the temperature display will be out of sync with the start and stop of the heating cable.

[0004] Therefore, it is urgent to design a standardized laying structure to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a laying structure of heating elements of a boron heating system of a nuclear power plant, and to standardize the laying of thermocouples, temperature switches and heating cables of the boron heating system.

[0006] The technical solution of the present invention is as follows:

[0007] A laying structure of heating elements of a boron heating system of a nuclear power plant, wherein a normal loop heating cable is arranged along the axis on the side wall of a process pipeline, and its position is defined as the circumferential 0° position of the process pipeline;

[0008] A spare loop heating cable is arranged at a 180° position in the circumferential direction of the process pipeline;

[0009] A normal circuit temperature switch capillary and a normal circuit thermocouple are provided at a 90° position on the circumference of the process pipeline, and a standby circuit thermocouple and a standby circuit temperature switch capillary are provided at a 270° position on the circumference of the process pipeline.

[0010] The normal circuit temperature switch capillary, normal circuit heating cable, standby circuit thermocouple, standby circuit temperature switch capillary, standby circuit heating cable and normal circuit thermocouple are all fixed on the process pipeline by winding with wire mesh.

[0011] A thermal conductive silicon mud layer is coated on the outside of the wire mesh to completely wrap the normal circuit temperature switch capillary, normal circuit heating cable, spare circuit thermocouple, spare circuit temperature switch capillary, spare circuit heating cable, and normal circuit thermocouple, so as to better conduct the heat of the process pipeline to the normal circuit temperature switch capillary, spare circuit thermocouple, spare circuit heating cable, and normal circuit thermocouple.

[0012] The outer side of the heat-conducting silicon mud layer is wrapped with a heat-insulating material to reduce the heat loss of the process pipeline.

[0013] The thickness of the thermal insulation material is greater than or equal to 1.5 cm.

[0014] The normal circuit temperature switch capillary is arranged near the side of the normal circuit heating cable, and the normal circuit thermocouple is arranged near the side of the standby circuit heating cable.

[0015] The standby circuit temperature switch capillary is arranged near one side of the standby circuit heating cable, and the standby circuit thermocouple is arranged near one side of the normal circuit heating cable.

[0016] When the temperature of the boron-containing medium in the process pipeline is lower than the set minimum value, the normal circuit heating cable and the backup circuit heating cable are heated at the same time, making the heating more uniform.

[0017] The remarkable effects of the present invention are:

[0018] The invention standardizes the laying of thermocouples, temperature switches and heating cables of the boron heating system of a nuclear power plant, avoiding problems such as inconsistent temperature display between the main control and local temperature display, frequent start and stop of the heating cable, and asynchronism between temperature display and start and stop of the heating cable caused by improper installation.

[0019] After the laying structure of the present invention was applied on-site in a nuclear power plant, it was verified that there were no more problems such as inconsistency between the temperature display of the main control and that of the local area, frequent start and stop of the heating cable, and asynchronism between the temperature display and the start and stop of the heating cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the installation of temperature probes in the boron heating system.

[0021] In the figure: 1. Normal circuit temperature switch capillary; 2. Normal circuit heating cable; 3. Process pipeline; 4. Standby circuit thermocouple; 5. Standby circuit temperature switch capillary; 6. Wire mesh; 7. Standby circuit heating cable; 8. Thermal conductive silica mud; 9. Insulation material; 10. Normal circuit thermocouple. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] The Boron heating system is designed with two identical heating circuits, which are divided into a normal circuit and a standby circuit. Each heating circuit includes a heating cable, a temperature switch, and a temperature measuring thermocouple. The normal circuit thermocouple sends the temperature signal to the main control display, and the standby circuit thermocouple sends the temperature signal to the local temperature indicator box for display.

[0024] like Figure 1 In the illustrated laying structure of heating elements of a nuclear power plant boron heating system, a normal loop heating cable 2 is arranged along the axis on the side wall of a process pipeline 3 , and its position is defined as the circumferential 0° position of the process pipeline 3 .

[0025] A backup loop heating cable 7 is arranged at a 180° circumferential position of the process pipeline 3. When the temperature of the boron medium in the process pipeline 3 is lower than the set minimum value, the normal loop heating cable 2 and the backup loop heating cable 7 are heated at the same time, making the heating more uniform.

[0026] A normal circuit temperature switch capillary 1 and a normal circuit thermocouple 10 are provided at a 90° position on the circumference of the process pipeline 3 , and a backup circuit thermocouple 4 and a backup circuit temperature switch capillary 5 are provided at a 270° position on the circumference of the process pipeline 3 .

[0027] The normal circuit temperature switch capillary 1 is arranged near the normal circuit heating cable 2, and the normal circuit thermocouple 10 is arranged near the standby circuit heating cable 7. The standby circuit temperature switch capillary 5 is arranged near the standby circuit heating cable 7, and the standby circuit thermocouple 4 is arranged near the normal circuit heating cable 2.

[0028] The normal circuit temperature switch capillary 1, the standby circuit temperature switch capillary 5, the normal circuit heating cable 2, and the standby circuit heating cable 7 are all spaced 90° apart, which can reduce the heating temperature interference of the normal circuit heating cable 2 and the standby circuit heating cable 7, so that the normal circuit temperature switch capillary 1 and the standby circuit temperature switch capillary 5 can more truly measure the temperature of the process pipeline 3.

[0029] The normal loop thermocouple 10, the backup loop thermocouple 4, the normal loop heating cable 2, and the backup loop heating cable 7 are all spaced 90° apart, which can reduce the heating temperature interference of the normal loop heating cable 2 and the backup loop heating cable 7, and make the temperature displayed by the normal loop thermocouple 10 and the backup loop thermocouple 4 closer to the actual temperature of the process pipeline 3.

[0030] The normal circuit temperature switch capillary 1, the normal circuit heating cable 2, the standby circuit thermocouple 4, the standby circuit temperature switch capillary 5, the standby circuit heating cable 7, and the normal circuit thermocouple 10 are all wound around and fixed on the process pipeline 3 through the wire mesh 6.

[0031] A thermal conductive silicone mud layer 8 is coated on the outside of the wire mesh 6 to completely wrap the normal circuit temperature switch capillary 1, the normal circuit heating cable 2, the standby circuit thermocouple 4, the standby circuit temperature switch capillary 5, the standby circuit heating cable 7, and the normal circuit thermocouple 10, so as to better conduct the heat of the process pipeline 3 to the normal circuit temperature switch capillary 1, the standby circuit thermocouple 4, the standby circuit heating cable 7, and the normal circuit thermocouple 10.

[0032] The heat-conducting silicon mud layer 8 is wrapped with a heat-insulating material 9 to reduce the heat loss of the process pipeline 3. The thickness of the heat-insulating material 9 is greater than or equal to 1.5 cm.

Claims

1. A laying structure of heating elements of a boron heating system in a nuclear power plant, characterized by: A normal loop heating cable (2) is arranged along the axis on the side wall of the process pipeline (3), and its position is defined as the circumferential 0° position of the process pipeline (3); A spare loop heating cable (7) is arranged at a 180° position in the circumferential direction of the process pipeline (3); A normal circuit temperature switch capillary (1) and a normal circuit thermocouple (10) are provided at a 90° position in the circumferential direction of the process pipeline (3), and a standby circuit thermocouple (4) and a standby circuit temperature switch capillary (5) are provided at a 270° position in the circumferential direction of the process pipeline (3); The normal circuit temperature switch capillary (1), the normal circuit heating cable (2), the standby circuit thermocouple (4), the standby circuit temperature switch capillary (5), the standby circuit heating cable (7), and the normal circuit thermocouple (10) are all wound around and fixed on the process pipeline (3) by means of a wire mesh (6); A heat-conducting silicon mud layer (8) is coated on the outside of the wire mesh (6) to completely wrap the normal circuit temperature switch capillary (1), the normal circuit heating cable (2), the standby circuit thermocouple (4), the standby circuit temperature switch capillary (5), the standby circuit heating cable (7), and the normal circuit thermocouple (10), so as to better conduct the heat of the process pipeline (3) to the normal circuit temperature switch capillary (1), the standby circuit thermocouple (4), the standby circuit heating cable (7), and the normal circuit thermocouple (10).

2. The laying structure of the heating element of the boron heating system of a nuclear power plant according to claim 1, characterized in that: The outer side of the heat-conducting silicon mud layer (8) is wrapped with a heat-insulating material (9) to reduce heat loss in the process pipeline (3).

3. The laying structure of the heating element of the boron heating system of a nuclear power plant according to claim 2, characterized in that: The thickness of the thermal insulation material (9) is greater than or equal to 1.5 cm.

4. The laying structure of the heating element of the boron heating system of a nuclear power plant according to claim 3, characterized in that: The normal circuit temperature switch capillary (1) is arranged close to the side of the normal circuit heating cable (2), and the normal circuit thermocouple (10) is arranged close to the side of the standby circuit heating cable (7).

5. The laying structure of the heating element of the boron heating system of a nuclear power plant according to claim 4, characterized in that: The standby circuit temperature switch capillary (5) is arranged close to the standby circuit heating cable (7) side, and the standby circuit thermocouple (4) is arranged close to the normal circuit heating cable (2) side.

6. The laying structure of the heating element of the boron heating system of a nuclear power plant according to claim 5, characterized in that: When the temperature of the boron-containing medium in the process pipeline (3) is lower than a set minimum value, the normal loop heating cable (2) and the standby loop heating cable (7) are heated simultaneously, so that the heating is more uniform.

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