Boron carbide nuclear neutron absorbing material and preparation method

Abstract

The invention relates to a boron carbide nuclear neutron absorbing material and a preparation method. The preparation method comprises the following steps: putting the three raw materials including 85percent by weight to 98.5 percent by weight of boron carbide powder (nuclear-grade powder), 1 percent by weight to 5 percent by weight of solid phase sintering additives and 0.5 percent by weight to10 percent by weight of liquid phase sintering additives into a ball mill mixing container; adding a polymer material as a soft template and adding deionized water to perform balling milling and pulping to obtain the slurry, wherein the solid phase content of the slurry is 40 percent by weight to 70 percent by weight; processing the slurry by using a spray drying granulating machine to obtain granulating powder; pressing the granulating powder by adopting the processes of dry pressing molding or cold isostatic pressing molding under the pressure of 50MPa to 300MPa to form green bodies; and putting the green bodies into a vacuum furnace, keeping a temperature for 0.5 hour to 5 hours under the temperature of 2000 DEG C to 2300 DEG C by adopting a vacuum or constant-pressure sintering way soas to complete sintering to obtain boron carbide ceramics. The boron carbide nuclear neutron absorbing material and the preparation method disclosed by the invention have the advantages that by usingthe boron carbide nuclear-grade powder as a raw material and the polymer material as the soft template, the boron carbide nuclear neutron absorbing material is prepared; the boron carbide nuclear neutron absorbing material has the advantages of low cost, batch production, low free carbon content and high neuron absorption efficiency, is suitable for preparing large-sized protection parts with complicated shapes, and has good application prospect in small nuclear reactor outer-layer protection and other types of nuclear reactor protection.

Description

Technical field: [0001] The invention relates to a technical method of a boron carbide nuclear neutron absorbing material with integrated structure and function, which belongs to the field of advanced ceramics. technical background: [0002] Boron carbide ceramics have a good ability to absorb neutrons, which is due to the isotope in natural boron 10 The thermal neutron capture cross section of B reaches 3850 / b. Therefore, in the nuclear industry, boron carbide ceramics are very important neutron absorbing materials. With the rapid development of the nuclear power industry, products such as boron carbide neutron absorbing balls, control rods, nuclear waste storage and laboratory boron carbide-based shielding plates have been widely used in various types of nuclear reaction systems. At the beginning of this century, the United States proposed the fourth-generation advanced nuclear energy reactor system, with development goals including sustainability, safety, reliability, a...

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Problems solved by technology

The hot pressing process is to apply a certain pressure to the boron carbide sintered body while sintering at high temperature to promote the densification of boron carbide ceramics. However, the output of a single furnace of the hot pressing process is limited, and only small-sized and relatively simple-shaped structural products can be prepared. , so hot-pressed boron carbide ceramics are very expensive

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