AQUEOUS LEACHABILITY OF LANTHANIDE AND PLUTONIUM TITANATES

The leachabilities of titanate and zircono-titanate solid solutions, C e2Ti2O7, Er1.78Ce0.22Ti2O7, Er1.78Pu0.22Ti2O7 (9.5 wt% Pu) Er1.78Ce0.2 2Ti0.5Zr1.5O7, SrCe2Ti4O12, SrPu2Ti4O12 (50.7 wt% Pu) and Sr2Ce2Ti5O16 , have been investigated in WIPP 'A' brine, 0.1 M NaCl, and 0.1 M HCl solutions using a modified MCC-3 procedure with a duration of 60 days. The concentrations of plutonium leached by the brine were less than 1 ppm. Where cerium was used as a surrogate for plutonium, its concentr ation in WIPP brine was below the limit of detection (10 ppm) establis hed for the inductively coupled plasma (ICP) atomic emission spectrome ter used. Concentrations of strontium leached by WIPP brine from stabl e strontium-containing titanate compounds, considered as possible immo bilizers of both Sr-90 and actinide elements, were on the order of 30- 60 ppm.