A manufacturing method of mass-producing fuel elements configured for use in a high-temperature gas cooled reactor core, wherein it uses additive manufacturing methods and robotic mechanisms to control spatial placement and packing density of particles within a matrix of graphite and comprises: repeatedly performing a sequence of operations comprising forming a uniform graphite layer on a previous layer and applying a binder using additive manufacturing methods to bind each layer with controlled exterior dimensions to form a base portion of the fuel elements; repeatedly performing a sequence of operations comprising depositing a uniform graphite layer of one of graphite powder, graphite spheres, or a combination of graphite powder and graphite spheres over a previous layer, forming a layer of particles on the uniform graphite layer within a fuel zone so that the particles are spaced apart in a predefined pattern, and applying a binder using additive manufacturing methods to bind each layer with controlled exterior dimensions to form a fuel zone portion of fuel elements; and repeatedly performing a sequence of operations comprising forming a uniform graphite layer on a previous layer and applying a binder using additive manufacturing methods to bind each layer with controlled exterior dimensions to form a cap portion of fuel elements, wherein the exterior dimensions of the graphite base portion, the fuel zone portion and the cap portion are controlled so as to form a fuel element of a controlled shape selected from the group consisting of spherical, ovoid, pill-shaped, prismatic, columnar, and conical, and wherein the particles comprise one or more of a fissile material, a burnable poison material, or a breeder material. repeatedly performing a sequence of operations comprising forming a uniform graphite layer on a previous layer and applying a binder using additive manufacturing methods to bind each layer with controlled exterior dimensions to form a base portion of the fuel elements; repeatedly performing a sequence of operations comprising depositing a uniform graphite layer of one of graphite powder, graphite spheres, or a combination of graphite powder and graphite spheres over a previous layer, forming a layer of particles on the uniform graphite layer within a fuel zone so that the particles are spaced apart in a predefined pattern, and applying a binder using additive manufacturing methods to bind each layer with controlled exterior dimensions to form a fuel zone portion of fuel elements; and repeatedly performing a sequence of operations comprising forming a uniform graphite layer on a previous layer and applying a binder using additive manufacturing methods to bind each layer with controlled exterior dimensions to form a cap portion of fuel elements, wherein the exterior dimensions of the graphite base portion, the fuel zone portion and the cap portion are controlled so as to form a fuel element of a controlled shape selected from the group consisting of spherical, ovoid, pill-shaped, prismatic, columnar, and conical, and wherein the particles comprise one or more of a fissile material, a burnable poison material, or a breeder material.