BEHAVIOR OF PLUTONIUM(V) IN ALKALINE MEDIA

In alkaline solutions with NaOH concentration below 8 M, Pu(V) has bee n found to be unstable, disproportionating to form Pu(IV) hydrous oxid e precipitate and dissolved Pu(VI). Sorption of Pu(V) on the freshly p recipitating Pu(IV) hydrous oxide and partial reduction of Pu(VI) by w ater alpha-radiolysis products complicate disproportionation of Pu(V). Disproportionation and reproportionation equilibrium constants were m easured in the range 4-8 M NaOH. The yield of disproportionation and r eproportionation reaction products increase with temperature and sharp ly fall with NaOH concentration. (C) 1998 Elsevier Science S.A.