The so-called Fluoride Volatility Processes refer to several proposed non-aqueous methods of processing irradiated fuel elements. In each of these methods, the uranium is fluorinated to UF6 and then decontaminated by distillation. One of those methods, involving the direct fluorination of the uranium by bromine trifluoride (BTF), has been under investigation at BNL since 1950. In 1952, it was demonstrated at BNL that uranium, as UF6, could be satisfactorily decontaminated by distillation in small-scale pilot plant equipment; end in 1953, BNL undertook the job of determining the technical feasibility of a continuous dissolver on a pilot-plant scale. The reason for the project was that the economic superiority of the process seemed to depend upon its amenability to continuous operation.

In a third run with the fluorine torch, the settling chamber wells were kept hotter than before (≥ 625°C); the flame was cooled by diluting the fluorine with helium. In the analysis of the products, 99% of the thorium fluoride fed in was accounted for, but only 64% of the protactinium activity. Part of this was carried in the exhaust gases past the cold trap and into the soda line disposal column, where it was detected by survey meters. The stripping of protactinium from the solid was somewhat more efficient than before; 77% of the feed which was recovered from the settling chamber had lost 72% of its original specific activity. About 15% of the input activity was trapped on the cold fingers with very little thorium fluoride.