Coated fuel pellets, methods of making and using same

A method of preparing a coated fuel pellet via atomic layer deposition (ALD), the method comprising:

• providing a green compact consisting of a fission material powder selected from uranium silicide, uranium nitride, uranium carbide, and combinations thereof, and gas trapped in pores and/or channels of the green compact, in an atomic layer deposition chamber and pulling a vacuum within the chamber at a rate of about 1 Torr/min to about 10 Torr/min until the atomic layer deposition chamber has a pressure of about 0.1 Torr to about 1.0 Torr thereby releasing the gas trapped in pores and/or channels of the green compact;
• depositing a protective coating on the green compact using atomic layer deposition such that the protective coating infiltrates into and coat the pores and/or channels of the green compact, to provide a protective-coated green compact, wherein the protective coating comprises a metal nitride, molybdenum, or a combination thereof;
• depositing an oxide-based coating on the protective-coated green compact using atomic layer deposition such that the oxide-based coating infiltrates into and coat the protective coating coated pores and/or channels of the protective-coated green compact, thereby providing an oxidation diffusion barrier;
• and,
• sintering the protective-coated green compact with the oxygen diffusion barrier, thereby providing the coated fuel pellet.