[en] Voloxidation is a proposed head-end process to remove tritium from irradiated LWR fuel by roasting the fuel in the presence of oxygen. The process oxidizes UO₂ to a fine U₃O₈ powder with high surface area for dissolution. Small-scale tests with irradiated Robinson, Oconee, and Saxton reactor fuels have been made to determine the dissolution behavior of both voloxidized and nonvoloxidized (UO₂) fuel. No significant technical problems were encountered in batch-dissolving of the U₃O₈ or UO₂ fuel. Dissolution rates were well-controlled in all tests. Significant observations from U₃O₈ dissolution, when compared to UO₂ dissolution, included: (1) reduced tritium and ruthenium (¹⁰⁶Ru) concentration in dissolver solutions, (2) increased weight of insoluble noble metal fission product residue (approximately 2.2X greater), and (3) increased fraction of the total plutonium which remains insoluble and is collected with the fission product residue. The insoluble plutonium was leached easily from the residue by 10M HNO₃ to ensure quantitative plutonium recovery. The weight of the fission product residue collected from both U₃O₈ and UO₂ fuels increased linearly with fuel burnup. A major fraction (> 88%) of the ⁸⁵Kr was evolved from U₃O₈ fuel during dissolution rather than voloxidation. The ⁸⁵Kr evolution rate was an appropriate monitor of fuel dissolution rate. Virtually all of the ¹²⁹I was evolved by air sparging of the dissolver solution during dissolution