Patent Number: 
Section: claims

1. A fully ceramic capsulated nuclear fuel material including three-layer-structured isotropic nuclear fuel particles with a coating layer having, comprising:three-layer-structured isotropic nuclear fuel particles;a coating layer cladding the three-layer-structured isotropic nuclear fuel particles, wherein the coating layer corresponds to a layer being formed by sintering a silicon carbide precursor, first silicon carbide, and a sintering additive; anda silicon carbide matrix phase enveloping the coating layer cladding the three-layer-structured isotropic nuclear fuel particles,wherein, when a shrinkage of the coating layer of the three-layer-structured isotropic nuclear fuel particles during a sintering process is given as ΔLC, and when a shrinkage of the silicon carbide matrix phase during the sintering process is given as ΔLm, a condition of ΔLC>ΔLm, is satisfied when performing pressureless sintering,wherein the silicon carbide precursor is shifted to second silicon carbide in order to densify the coating layer during the sintering process such that the shrinkage of the coating layer is greater than the shrinkage of the silicon carbide matrix phase. 2. The nuclear fuel material of claim 1, wherein the sintering is performed by a pressureless sintering process, wherein the coating layer has a remaining porosity of more than 0% and less than or equal to 4% after performing the pressureless sintering process, and wherein an amount of the three-layer-structured isotropic nuclear fuel particles without the coating layer is in the range of 5-40 volume %.