Use of Triflic Acid in the Recycling of Thoria from Nuclear Fuel Production Scrap

The complexity in the dissolution of thoria (ThO2) and thorium-based fuels at an industrial scale is one of the limiting factors for the implementation of the thorium fuel cycle. In this study, we investigated the dissolution of unirradiated thoria powder, simulating thoria from nuclear fuel production scrap, in trifluoromethanesulfonic acid (triflic acid) solutions. The dissolution method was compared with the standard thorium uranium extraction (THOREX) dissolution process. The viability of the conversion of thorium(IV) triflate into thoria via oxalic acid precipitation and calcination was demonstrated, and the obtained thorium(IV) oxalate intermediate was characterized. Spent triflic acid could be recycled and reused for dissolution of a new batch of thoria. A triflic acid-based route could hence be considered a viable alternative for the standard THOREX-reagent-based process.status: publishe