A solution containing kilogram quantities of highly radioactive isotopes ofamerícium and curium (Am/Cm) and lanthanide fission products is currentlystored in a process tank at the Department of Energy's Savannah River Site(SRS). This tank and its vital support systems are old, subject todeterioration, and prone to possible leakage. For this reason, a program hasbeen initiated to stabilize this material as a lanthanide borosilicate (LBS) glass.1 The Am/Cm has commercial value and is desired for useby the heavy isotope programs at the Oak Ridge National Laboratory(ORNL).

A recovery flowsheet was demonstrated using a curium-containing glass toextract the Am/Cm from the glass matrix. The procedure involved grinding theglass to less than 200 mesh and dissolving in concentrated nitric acid at110°C. Under these conditions, the dissolution was essentially 100% after 2hours except for the insoluble silicon. Using a nonradioactive surrogate,the expected glass dissolution rate during Am/Cm recovery was bracketed byusing both static and agitated conditions. The measured rates, 0.0082 and0.040 g/hrcm2, were used to develop a predictive model for thetime required to dissolve a spherical glass particle in terms of the glassdensity, particle size, and measured rate. The calculated dissolution timewas in agreement with the experimental observation that the curium glassdissolution was complete in less than 2 hr.