The development of advanced fuel fabrication technologies is important for developing accident-tolerant fuels and engineering fuels for safer and more effective nuclear energy systems. In this work, commercial-size uranium dioxide (UO2) fuel pellets with a theoretical density of 95% were consolidated by spark plasma sintering (SPS) at 1600°C for 5 min. Systematic investigations suggest uniform densification and stoichiometric UO2 with an ideal fluorite structure across the commercial-size fuel pellet, but with a distributed grain structure because of non-uniform distribution of temperature during sintering. This work demonstrates a great potential of using SPS for fabricating nuclear fuels at a cost-effective manner.