Preparation method of nuclear grade boron carbide core block for high-temperature gas cooling pile control rod

A high-temperature gas-cooled reactor and boron carbide technology, which is applied in the field of preparation of nuclear materials and ceramic materials, can solve problems such as the inability to prepare large-sized nuclear-grade boron carbide pellets, and achieve the effects of reducing production costs and improving preparation efficiency.

Active Publication Date: 2016-08-31
NUCLEAR POWER INSTITUTE OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for preparing nuclear-grade boron carbide pellets for high-temperature gas-cooled reactor control rods, which solves the problem that neither the current hot-pressing process nor the pressureless sintering process can produce large-size nuclear-grade boron carbide pellets

Method used

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Embodiment 1

[0031] A method for preparing nuclear-grade boron carbide pellets for high-temperature gas-cooled reactor control rods according to the invention, with an average particle size of 0.5 μm and a specific surface area of ​​18 m 2 / g boron carbide powder as raw material, boron carbide powder is mixed with 6% alcohol solution of phenolic resin in proportion, mixed, dried at 80°C, granulated by wiping sieve, passed through 60 mesh sieve, and formed by steel mold The method is to form under the pressure of 50MPa, and then use the cold isostatic press to form under the forming pressure of 300MPa. After the green body is formed, the density reaches 70%. The forming taper of the green body is cut off by machining, and the boron carbide green body is put into In the sintering furnace, degreasing is carried out under vacuum, the heating rate is 1°C / min, the highest degreasing temperature is 800°C, the holding time at 800°C is 1 hour, and then the temperature is raised to 1500°C at a heatin...

Embodiment 2

[0033] A method for preparing nuclear-grade boron carbide pellets for high-temperature gas-cooled reactor control rods according to the invention, with an average particle size of 0.5 μm and a specific surface area of ​​18 m 2 / g boron carbide powder as raw material, boron carbide powder is mixed with 1% alcohol solution of phenolic resin in proportion, mixed, dried at 80°C, granulated by wiping sieve, passed through 60 mesh sieve, and molded with steel mold The method is to form under the pressure of 150MPa, and then use the cold isostatic press to form under the forming pressure of 200MPa. After the green body is formed, the density reaches 63%. The forming taper of the green body is cut off by machining, and the boron carbide product is put into the sintered In the furnace, degreasing is carried out under vacuum, the heating rate is 3°C / min, the highest degreasing temperature is 1000°C, the holding time at 1000°C is 1 hour, the temperature is raised to 1500°C at a heating ra...

Embodiment 3

[0035] A method for preparing nuclear-grade boron carbide pellets for high-temperature gas-cooled reactor control rods according to the invention, with an average particle size of 3 μm and a specific surface area of ​​5 m 2 / g boron carbide powder as raw material, boron carbide powder is mixed with 4% alcohol solution of phenolic resin in proportion, mixed, dried at 80 ℃, granulated by wiping sieve, passed through 20 mesh sieve, and formed by steel mold The method is to form under the pressure of 100MPa, and then use the cold isostatic press to form under the forming pressure of 300MPa. After the green body is formed, the density reaches 66%. The taper of the sample is cut off by machining, and the boron carbide product is put into the sintering furnace degreasing under vacuum, the heating rate is 2°C / min, the maximum degreasing temperature is 900°C, the holding time at 900°C is 1 hour, and the temperature is raised to 1500°C at a heating rate of 3°C / min, and filled with high-p...

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Abstract

The invention discloses a preparation method of a nuclear grade boron carbide core block for a high-temperature gas cooling pile control rod. Nuclear grade boron carbide powder is used as raw materials; the large-dimension nuclear grade boron carbide core block for the high-temperature gas cooling pile control rod is prepared through nine steps including material mixing, drying, pelletization, steel mold forming, cold isostatic pressing, green blank processing, degreasing, sintering and machining; the large-dimension nuclear grade boron carbide core block can be prepared in a mass and net dimension manner; a pressure-free sintering process is used for replacing a hot pressing process, so that the problems of high production cost and low efficiency of the large-dimension nuclear grade boron carbide core block are solved. The method can be directly used for producing the boron carbide core block for the high-temperature gas cooling pile control rod.

Description

technical field [0001] The invention relates to the preparation technology of nuclear materials and ceramic materials, in particular to a method for preparing nuclear-grade boron carbide pellets for high-temperature gas-cooled reactor control rods. Background technique [0002] High-temperature gas-cooled reactor nuclear power plants use boron carbide pellets as the neutron absorbing material for control rods. There are 8 specifications of boron carbide pellets for boron carbide control rods. Type, there are 6 bosses connected to the core block at the end of the outer rod, the shape is more complicated, and the boron carbide impurity content is required to be nuclear grade. According to the literature "High temperature gas-cooled reactor control rod B 4 Development of C Pellets” reported that Mudanjiang Diamond Company has developed nuclear-grade boron carbide pellets for control rods for high-temperature gas-cooled reactors by hot pressing. The batch is small, and a total ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G21C21/18G21C7/24C04B35/563C04B35/64
CPCC04B35/563C04B35/64C04B2235/668G21C7/24G21C21/18Y02E30/30
Inventor 李圆圆刘海杨静潘小强尹昌耕黄卫东喻冲
Owner NUCLEAR POWER INSTITUTE OF CHINA
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