Abstract: The application discloses a preparation method of monocrystal uranium dioxide nuclear fuel pellets, comprising: granulating and pelleting UO2 powder to obtain UO2 pellets; then coating surfaces of the UO2 pellets with monocrystal growth additive micro powder to form core-shell structure particles; and activated-sintering the core-shell structure particles at high temperature, liquefying the monocrystal growth additive on the surface of the core-shell structure particle at high temperature and then diffusing into UO2 pellets, dissolving the UO3 in the liquid monocrystal growth additive, and recrystallizing the UO2 to form the monocrystal UO2 nuclear fuel pellets.

Abstract: The application discloses a preparation method of monocrystal uranium dioxide nuclear fuel pellets, comprising: granulating and pelleting UO2 powder to obtain UO2 pellets; then coating surfaces of the UO2 pellets with monocrystal growth additive micro powder to form core-shell structure particles; and activated-sintering the core-shell structure particles at high temperature, liquefying the monocrystal growth additive on the surface of the core-shell structure particle at high temperature and then diffusing into UO2 pellets, dissolving the UO3 in the liquid monocrystal growth additive, and recrystallizing the UO2 to form the monocrystal UO2 nuclear fuel pellets.

Abstract: A method for avoiding a polysilicon defect includes: forming a silicon oxide layer on a silicon substrate; forming a polysilicon plug in the silicon oxide layer, with the polysilicon plug going through the silicon oxide layer; forming on the silicon oxide layer a silicon nitride layer covering the polysilicon plug; forming interlayer dielectric layers on the silicon nitride layer; etching the interlayer dielectric layers over the polysilicon plug to form an opening; etching the silicon nitride layer at the opening to expose the polysilicon plug; and filling polysilicon into the opening such that the opening is in communication with polysilicon plug. In this way, there will be no reaction of the HSC1 with the polysilicon plug due to the protection by the silicon nitride layer. Moreover, since the silicon nitride layer is the last to be etched, there will be no residual thereof, enabling a subsequent flat filling.