Treatment of sodium fluoride absorbent contaminated with plutonium - where repeated leaching with nitric acid dissolves part of sodium fluoride so plutonium is conc. in residue

摘要

Part of a contaminated absorbent (I), esp. NaF contg. Pu, is dissolved in a soln. so the latter is satd. with NaF. Further contaminated NaF and more soln. are added, so while most of the NaF is dissolved, the Pu remains in the residual NaF and is thus conc. The residue is then treated to recover the Pu. The pref. process is carried out in numerous stages, so a high concn. of Pu is obtd. in the final residue, which is pref. dissolved in HNO3 contg. Al(NO3)2 and then an organic solvent, e.g. tributyl phosphate, is used to extract the Pu. Used in the dry retreatment of irradiated nuclear fuel elements, NaF contg. Pu as PuNa2F6 is obtd. The invention is used to reclaim the Pu.