DIFFUSION OF ACTINIDES IN GLASSES CONTAINING MODEL RADIOACTIVE-WASTES

Diffusion coefficients of Np-237, Pu-239, and Am-241 are determined in two model aluminophosphate and aluminoborosilicate glasses at temperatures slightly lower than their transformation temperatures. The actinides are one of the least mobile elements. In particular, the actinide diffusion coefficients in the aluminophosphate glasses at 673 K are of the order of 10(-18) m2.sec-1; in the aluminoborosilicate glasses at 773 K, of the order of 10(-19) m2.sec-1. Crystallization of the glasses increases the diffusional mobility of Np-237. A rather small amount of water absorbed by the crystallized aluminophosphate glass increases the low-temperature migration of Np-237.