Evaluation of sodium borate glasses for radioactive waste immobilization applications

Properties of sodium borate glasses, including chemical durability, leaching rate, glass transformation temperature, and melting temperature were analyzed for waste immobilization applications. The lowest dissolution rate (1.6 x 10(-8) g cm(-2) min(-1)) among candidate sodium borate host glasses was achieved in 45Na(2)O center dot 5P(2)O(5)center dot 5PbO center dot 45B(2)O(3). Similarly, the lowest dissolution rate (5.5 x 10(-8) g cm(-2) min(-1)) for simulated waste glass compositions was achieved in 20SrO center dot 80(30Na(2)O center dot 60PbO center dot 10B(2)O(3)). Clear vitrified waste products containing up to 35 mol% SrO and 25 mol% Cs2O were obtained. Low melting temperatures ranging from 222 to 440 A degrees C were achieved in simulated waste glasses.