Evaluation of SYNROC-C as a second generation waste form

Synroc-C was evaluated as a candidate second generation waste form, relative to 76-68 borosilicate glass, by leach testing both monolithic and powdered samples at 90 degrees Celsius and 150 degrees Celsius in brine and silicate solutions. Additional short term tests were made at low surface area to volume ratios between 90 degrees Celsius and 250 degrees Celsius to estimate forward direction leach rates and activation energies. Dissolution rates of Cs, Mo, Ba and U indicated that Synroc-C generally performed about an order of magnitude better than 76-68 glass. The release of Cs and Mo from Synroc may be from intergranular regions initially. Activation energies for these two elements from glass were about 9 kcal/mol, but less than 3 kcal/mol from Synroc-C