Evaluation of SYNROC-C as a Second Generation Waste Form

Abstract

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 C and 150 degrees C in brine and silicate solutions. Additional short term tests. were made at low surface area to volume ratios between 90 degrees C and 250 degrees C 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.