Fragmentation of fully ceramic microencapsulated fuel simulants by high current electrical arcing

Reprocessing TRi-structural ISOtropic (TRISO) coated particle fuel remains a significant challenge for nuclear fuel recycling due to its multi-layer architecture and the high fracture strength of certain layers. Addressing this issue is critical for closing the nuclear cycle and reducing long-term waste. This study proposes a novel, energy-efficient solution, high-current electrical arcing, to disintegrate TRISO particles embedded in a ceramic matrix. The technique applies controlled high-current arcing, produced by high-voltage discharges (up to 3.95 kV), generating currents of several kA to achieve breakdown of both the matrix and TRISO’s layers while protecting the fuel kernel. The results demonstrate that repeated arcing effectively disintegrates the graphite matrix, liberating TRISO particles and inflicting structural damage on subsequent particle layers, achieving the efficient layer separation. Microstructural analysis revealed that fractures preferentially propagate along the TRISO-matrix interface, enhancing liberation efficiency. Further direct arcing on isolated particles breaches the multi-layer coating, fracturing both the outer pyrolytic carbon and the silicon carbide (SiC) containment layer, exposing the inner carbon layers. Each discharge consumed only approximately 1.0 × 10⁻⁴ kWh, demonstrating exceptional energy efficiency. Subsequent visual and material analysis, along with multiple rounds of testing on different fuel pellet samples, confirmed the effectiveness and repeatability of this approach. Findings indicate that this single-step method could significantly simplify future recycling processes and accelerate progress toward sustainable nuclear energy systems.