405. Uniaxial Manufacturing of Fully Ceramic Microencapsulated (FCM®) Fuel

Presenter(s)

Ethan Deters

Abstract or Description

One innovation in nuclear fuel types with higher safety margins and increased accident tolerance is Fully Ceramic Microencapsulated (FCM) fuel. This fuel contains particle fuel, such as Tristructural Isotropic (TRISO) fuel particles embedded in a ceramic matrix. This fuel type benefits safety margins with its fission product retention, irradiation stability, and improved oxidation rates. However, manufacturing these fuel pellets has proved difficult. In this research, a novel, layering approach to loading TRISOs into a randomly packed 2D planes was explored. The TRISOs were randomly assorted into a bed of uniaxially pressed SiC powder layer-by-layer, then sintered in a Spark Plasma Sintering (SPS) machine. The fully sintered pellets’ density and porosity was taken from bulk dimensional measurements, from fluid displacement measurements, and through microscopy. This effort revealed that the volume packing fraction of TRISO fuel particles has a limiting effect on matrix porosity, or full densification, of the ceramic matrix. The ceramic matrix had increases in both local and open porosity for higher fuel loadings. The increased porosity was also linked to higher fuel loadings. A fully dense and non-porous FCM fuel design indicates passively safe and economically competitive nuclear reactor designs. Research to obtain this goal is ongoing.

Mentor

Dr. Caen Ang