Inert matrix dispersion fuel pellet and preparation method thereof

Abstract

The invention discloses an inert matrix dispersion fuel pellet and a preparation method thereof. The preparation method includes: S1, prefabricating a fuel-free area, specifically, pressing SiC mixedpowder into a tubular shape or a disc shape, and performing pressureless sintering; S2, prefabricating a fuel area, specifically pressing TRISO (tri-structural iso-tropic) particles with SiC coatingsinto a cylindrical shape; S3, filling the cylindrical-shaped materials into the tubular-shaped materials, then placing the disc-shaped materials at the opposite both ends of the tubular-shaped materials, performing discharge plasma sintering to obtain the inert matrix dispersion fuel pellet, wherein the cylindrical-shaped materials form the fuel area of the inert matrix dispersion fuel pellet, andthe tubular-shaped materials and the disc-shaped materials form the fuel-free area of the inert matrix dispersion fuel pellet. According to the preparation method of the inert matrix dispersion fuelpellet, by prefabricating the fuel-free area, the density of the fuel-free area is controlled to be close to that the pressed fuel area, the density difference between the fuel area and the fuel-freearea of the sintered inert matrix dispersion fuel pellet can be reduced, the peripheral contour structure of TRISO particles inside the fuel area can be improved, the fuel area can be expanded, the overall TRISO volume content of the inert matrix dispersion fuel pellet can be increased, and the comprehensive performance of the inert matrix dispersion fuel pellet can be further enhanced.

Description

technical field [0001] The invention relates to the technical field of nuclear fuel, in particular to an inert matrix dispersed fuel pellet and a preparation method thereof. Background technique [0002] Nuclear fuel has a high energy density, CO 2 It is an important means to solve the shortage of petrochemical resources and serious environmental pollution. Nuclear power generation is clean energy, and nuclear power has obvious advantages. As the proportion of nuclear power energy continues to increase, the status of nuclear power generation becomes more prominent. However, nuclear energy uses the energy generated by the fission of heavy metal elements such as uranium, which will form fission products with certain radioactivity. Therefore, doing a good job in radiation protection and preventing the leakage of radioactive products is the key to the safety of nuclear power and the prerequisite for the development of nuclear energy. There have been many nuclear and radioacti...

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Problems solved by technology

[0005] The IMDP pellets are TRISO microspheres dispersed in the SiC matrix of the powder. The Oak Ridge National Laboratory of the United States adopts the method of hot pressing sintering, mixing TRISO particles with SiC powder and then hot pressing sintering. This process is relatively mature and compared with The thermal conductivity of pure UO2 pellets has been improved to a certain extent, but this method has some disadvantages: (1) the process of pressing the green body is difficult, especially the fuel-free area of ​​the outer layer, which often cannot be tightly combined with the fuel area; (2) the sintering temperature High, not conducive to the improvement of the overall performance of the pellet

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