Small Size UO2 Microsphere Preparation for a HTGR Nuclear Fuel

Generally, the nuclear fuel of a HTGR has used TRISO(TRistructural ISOtropic) coated fuel particles which is enclosed by the three layers of coating materials, such as pyrolytic carbon(PyC), as buffer layer, inner dense PyC(IPyC) layer, silicon carbide(SiC) layer, and outer PyC(OPyC) layer at the surface of spherical UO2 kernels as shown. The key process in a HTGR nuclear fuel is a spherical UO2 kernel preparation process. Since the 1970s, many methods for a spherical UO2 kernel particle preparation have been investigated based on the sol-gel process (internal and external gelations), and a suspension process with a temporary binder, and a mixed process(sol-gel process and suspension). We selected the gel-supported precipitation processes. Sol-gel processes in the nuclear fuel preparation field have many advantages at a high purity atmosphere and low processing temperature