Glass-metal sealing material for pressurized water reactor electrical penetration conductor assembly and preparation method thereof

Abstract

The invention discloses a glass-metal sealing material and a preparation method for a conductor assembly of an electrical penetration of a pressurized water reactor. The glass material ratio is set and the raw materials of each component are weighed and mixed evenly to obtain a batch material. The batch material includes, in terms of weight percentage based on oxides: SiO2: 50-70%, B2O3: 8-13%, Al2O3: 4-8%, Na2O: 3-8%, CeO2: 2-4%, K2O: 0-2%, TiO2: 0-2%, CaO: 0-2%, ZrO2: 0-1%, and CoO: 0-1%. The batch material is melted at 1550-1650°C, and glass slag is obtained after quenching. The glass slag is ball-milled and spray-granulated to obtain granulated powder with a certain particle size and sphericity. The granulated powder is made into a glass blank of a desired shape by compression molding, and is placed at a certain temperature for debinding and vitrification to obtain prefabricated glass beads. After assembling the metal shell, the metal conductor and the prefabricated glass beads, they are sealed in an atmosphere furnace to obtain a glass-metal sealed electrical penetration conductor assembly. The conductor assembly prepared by this method has the characteristics of high air tightness, high insulation, radiation resistance, flame retardancy, etc.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear reaction safety, and in particular to a glass-metal sealing material for a conductor assembly of an electrical penetration piece of a pressurized water reactor and a preparation method thereof. Background Art

[0002] The full name of PWR is "pressurized water moderated and cooled reactor". It is a reactor that uses pressurized, non-boiling light water (i.e. ordinary water) as moderator and coolant. It is composed of fuel assembly, moderator (also used as coolant), control rod assembly, burnable poison assembly, neutron source assembly, core basket and pressure vessel. It is a type of reactor with a large number of applications and a large capacity in nuclear power plants.

[0003] The electrical penetration of a pressurized water reactor is a special electrical device installed on the reactor containment for the cable to pass through the containment. Under normal and various accident conditions, the electrical penetration should be able to ensure the integrity of the containment, prevent the leakage of radioactive materials, and maintain the continuity of the electrical and signal inside the containment. The main functional components of the electrical penetration include the conductor assembly and the cylinder assembly. The conductor assembly runs through the entire cylinder assembly to achieve physical connection of various cables inside and outside the containment. While achieving the electrical connection and signal transmission functions, it works together with the penetration cylinder assembly to achieve the integrity of the containment pressure boundary.

[0004] The electrical penetration conductor assembly is mainly composed of a metal shell, a metal conductor and a sealing material, wherein the types of sealing materials mainly include polymers, glass and ceramics. The metal shell and the metal conductor are sealed by the sealing material, so the selection of the sealing material determines the performance of the electrical penetration conductor assembly. Currently, polymer sealing materials are the most widely used in pressurized water reactor electrical penetrations.

[0005] Although polymer sealing materials can meet the strict standards of electrical penetrations in all aspects of performance, polymer materials are inevitably prone to aging phenomena such as embrittlement and creep during long-term operation and extended life operation. After aging, there is a risk of losing sealing and insulation functions in the event of high temperature, high humidity, or high radiation accidents. Using glass-metal sealing materials to replace polymer sealing materials used in electrical penetration conductor assemblies can improve the sealing performance of pressure boundaries under extreme working conditions and reduce the risk of radioactive leakage after an accident. Therefore, glass-metal sealed electrical penetration conductor assemblies have become a safer and more reliable choice. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention aims to provide a glass-metal sealing material and a preparation method for a pressurized water reactor electrical penetration conductor assembly. The electrical penetration prepared by the method has the characteristics of high air tightness, high insulation, radiation resistance, flame retardancy, etc., thereby solving the shortcomings and defects of the material itself in the polymer sealed electrical penetration conductor assembly.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a glass-metal sealing material for a pressurized water reactor electrical penetration conductor assembly, the pressurized water reactor electrical penetration conductor assembly is mainly composed of a metal shell, a metal conductor and a sealing material, the sealing material is a glass material, and the components of the glass material are calculated by weight percentage based on oxides: SiO2: 50-70%, B2O3: 8-13%, Al2O3: 4-8%, Na2O: 3-8%, CeO2: 2-4%, K2O: 0-2%, TiO2: 0-2%, CaO: 0-2%, ZrO2: 0-1%, CoO: 0-1%, and the sum of each component is 100%.

[0008] Furthermore, the material of the metal shell is 06Cr19Ni10 stainless steel.

[0009] Furthermore, the metal conductor is made of oxygen-free copper.

[0010] Furthermore, the expansion coefficient of the glass material is 170-180×10 -7 / K.

[0011] A method for preparing a glass-metal sealing material for a pressurized water reactor electrical penetration conductor assembly, the method comprising the following steps:

[0012] Step (1), according to the glass ratio, weigh the raw materials SiO2: 50-70%, B2O3: 8-13%, Al2O3: 4-8%, Na2O: 3-8%, CeO2: 2-4%, K2O: 0-2%, TiO2: 0-2%, CaO: 0-2%, ZrO2: 0-1%, CoO: 0-1%, and place the raw materials in a V-type mixer and mix for 30-40 minutes;

[0013] Step (2), the uniformly mixed raw materials are kept at 1550-1650° C. for 80-100 minutes for high temperature melting, and glass slag is obtained after water quenching;

[0014] Step (3), grinding the glass slag in a planetary ball mill, adding grinding balls at a material-ball ratio of 1:0.8-1, and the ball milling time is 100-120 min; sieving the ground glass powder, and taking the glass powder under a 150-mesh sieve for later use;

[0015] Step (4), dispersing the glass powder under a 150-mesh sieve in a liquid phase consisting of a solvent, a dispersant and a binder, adding grinding balls, and ball milling for 100 to 120 minutes to obtain a glass powder slurry; the mass ratio of the glass powder, the solvent, the dispersant, the binder and the grinding balls is 110:70 to 76:0.8 to 1.2:11 to 14:165 to 180;

[0016] Step (5), placing the glass powder slurry in a spray granulation tower for spray granulation, sieving the obtained granulated powder, and taking the granulated powder between 80 and 200 meshes for later use;

[0017] Step (6), preparing the granulated powder into the required glass blank by pressing, debinding the glass blank at 360-600° C., and vitrifying the glass blank at 650-700° C. to obtain the required glass beads;

[0018] Step (7), assemble the metal shell, glass beads, metal conductor, and sintering mold together, put them into an atmosphere sintering furnace, introduce nitrogen, and keep them at 960-980° C. for 15-20 minutes for sealing.

[0019] Furthermore, in step (4), the solvent is deionized water, the dispersant is sodium polyacrylate, the binder is polyethylene glycol, and the grinding balls are zirconium oxide balls with a diameter of 5 mm.

[0020] Furthermore, in step (7), the sintering mold is made of graphite material.

[0021] The beneficial effects of the present invention are as follows: compared with the prior art, the glass-metal sealing material and preparation method for the conductor assembly of the electrical penetration of a pressurized water reactor provided by the present invention have a difference in expansion coefficient between the sealing glass prepared by the present invention and the metal shell and the pin within 10%, and matching sealing can be achieved. The advantage of matching sealing is that the stress in the sealing system can be controlled within a safe range, and the sealing glass will not produce defects such as cracks and bubbles due to excessive stress, so the conductor assembly sealed by the sealing material prepared by the present invention has high airtightness. At the same time, the sealing glass formula designed by the present invention is a high borosilicate glass system, and the alkali metal oxide content is relatively small, which has little effect on the conductivity of the entire glass system. Therefore, the conductor assembly sealed by the sealing material prepared by the present invention has high insulation, and the glass material of the system has better stability at high temperature than polymer materials and has better flame retardancy. The formula also adds rare earth oxide cerium oxide, which can improve the radiation resistance of the glass material. Therefore, the conductor assembly sealed by the sealing material has the characteristics of high airtightness, high insulation, radiation resistance, flame retardancy, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the sealing of the coaxial conductor assembly provided by the present invention.

[0023] Among them, 1-metal shell; 2-metal conductor; 3-sealing material. DETAILED DESCRIPTION

[0024] The present invention is further described below by specific examples, but these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0025] Embodiments 1 to 4

[0026] 1) According to the glass ratio, weigh the raw materials SiO2: 50-70%, B2O3: 8-13%, Al2O3: 4-8%, Na2O: 3-8%, CeO2: 2-4%, K2O: 0-2%, TiO2: 0-2%, CaO: 0-2%, ZrO2: 0-1%, CoO: 0-1%, and place the raw materials in a V-type mixer and mix for 30-40 minutes;

[0027] 2) The uniformly mixed raw materials are kept at 1600° C. for 100 minutes for high temperature melting, and glass slag is obtained after water quenching;

[0028] 3) Grind the glass slag in a planetary ball mill, add grinding balls at a material-ball ratio of 1:0.8, and grind for 120 minutes. Sieve the ground glass powder and take the glass powder under the 150-mesh sieve for later use;

[0029] 4) dispersing the glass powder under a 150-mesh sieve in a liquid phase consisting of a solvent, a dispersant and a binder, adding grinding balls, and ball milling for 100 minutes to obtain a glass powder slurry, wherein the mass ratio of the glass powder, the solvent, the dispersant, the binder and the grinding balls is 110:76:1:13:165;

[0030] 5) The glass powder slurry is placed in a spray granulation tower for spray granulation. The obtained granulated powder is sieved and the granulated powder with a mesh size of 80 to 200 is selected for use.

[0031] 6) The granulated powder is prepared into the required glass blank by compression molding, the glass blank is debinded at 360-600°C, and the glass blank is vitrified at 650-700°C.

[0032] 7) Assemble the metal shell 1, the prefabricated glass beads as the sealing material 3, the metal conductor 2, and the sintering mold together, put them into an atmosphere sintering furnace, and introduce nitrogen, and keep the temperature at 960-980°C for 20 minutes for sealing.

[0033] The gas leakage rate, insulation resistance, withstand voltage value, and withstand voltage value of the glass-metal sealed conductor assembly are tested. The gas leakage rate is measured by a helium mass spectrometer leak detector, the insulation resistance is measured by an insulation resistance tester, the withstand voltage value is measured by a withstand voltage tester, and the withstand voltage value is measured by a high-temperature well logging pressure test chamber. The above performance test data are summarized in the following table:

[0034]

[0035]

[0036] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. A glass-metal sealing material for a pressurized water reactor electrical penetration conductor assembly, characterized in that: The pressurized water reactor electrical penetration conductor assembly is mainly composed of a metal shell, a metal conductor and a sealing material. The sealing material is a glass material. The components of the glass material are as follows: SiO2: 67%, B2O3: 10%, Al2O3: 8%, Na2O: 4%, CeO2: 3%, K2O: 2%, TiO2: 2%, CaO: 2%, ZrO2: 1%, CoO: 1% based on the weight percentage of the oxides. The material of the metal shell is 06Cr19Ni10 stainless steel; the material of the metal conductor is oxygen-free copper; the expansion coefficient of the glass material is 170-180×10 -7 / K; A method for preparing a glass-metal sealing material for a pressurized water reactor electrical penetration conductor assembly, the method comprising the following steps: 1) According to the glass ratio, weigh the raw materials SiO2: 67%, B2O3: 10%, Al2O3: 8%, Na2O: 4%, CeO2: 3%, K2O: 2%, TiO2: 2%, CaO: 2%, ZrO2: 1%, CoO: 1%; place the raw materials in a V-type mixer and mix for 30 to 40 minutes; 2) The uniformly mixed raw materials are kept at 1600° C. for 100 minutes for high temperature melting, and glass slag is obtained after water quenching; 3) Grind the glass slag in a planetary ball mill, add grinding balls at a material-ball ratio of 1:0.8, and grind for 120 min. Sieve the ground glass powder and take the glass powder under the 150-mesh sieve for later use; 4) dispersing the glass powder under a 150-mesh sieve in a liquid phase consisting of a solvent, a dispersant and a binder, adding grinding balls, and ball milling for 100 minutes to obtain a glass powder slurry, wherein the mass ratio of the glass powder, the solvent, the dispersant, the binder and the grinding balls is 110:76:1:13:165; the solvent is deionized water, the dispersant is sodium polyacrylate, the binder is polyethylene glycol, and the grinding balls are zirconia balls with a diameter of 5 mm; 5) placing the glass powder slurry in a spray granulation tower for spray granulation, sieving the obtained granulated powder, and taking the granulated powder between 80 and 200 meshes for use; 6) preparing the granulated powder into the required glass blank by pressing, debinding the glass blank at 360-600° C., and vitrifying the glass blank at 650-700° C.; 7) Assemble the metal shell, prefabricated glass beads as sealing materials, metal conductors, and sintering molds together, put them into an atmosphere sintering furnace, introduce nitrogen, and keep them at 960-980° C. for 20 minutes for sealing; the sintering mold is made of graphite material.

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