Solubility control of actinide elements leached from Synroc in pH-buffered solutions

Abstract

Actinide-doped Synroc samples were leached in deionized water and buffered solutions (pH 2 to 10) under MCC-1 conditions at 70°C for 28 days. Leachates were filtered through 0.45 µm and colloid filters to determine the α-activity associated with colloids and particulates. The EQ3/6 thermodynamic package was used to calculate whether actinide solubility limits were affecting Synroc dissolution kinetics. For Pu, the solubility in all leachants, except the pH 2 buffer, appeared to control the dissolution kinetics, but for Np and Am, the dissolved actinides were below solubility limits in each case. To avoid Pu saturation effects in MCC tests on Synroc, shorter leaching times will have to be used. ©1992 R. Oldenbourg Verlag,.