The self-diffusion coefficients of Na in P0798 (SiO2-14.2B2O3-5Al2O3-3Li2O-3CaO-3wt%ZnO) simulated nuclear waste glass were measured (table 174) by using an ion beam sputter-sectioning technique and the radioactive isotope, 22Na. The temperature dependence of the diffusion coefficients below the glass transition temperature Tg could be expressed by:

428-574K:     D (m2/s) = 2.7 x 10-6 exp[-113(kJ/mol)/RT]

Self-Diffusion of 22Na and 137Cs in Simulated Nuclear Waste Glass. K.Nonaka, H.Nakajima, S.Mitsui, J.Echigoya: Materials Transactions, 2002, 43[4], 654-9

Table 174

Diffusion of 22Na in P0798 (SiO2-14.2B2O3-5Al2O3-3Li2O-3CaO-3wt%ZnO) Glass

below the Glass Transition Tempertature

 

Temperature (K)

D (m2/s)

574

4.80 x 10-16

524

3.05 x 10-17

499

7.27 x 10-18

477

6.17 x 10-19

451

2.48 x 10-19

428

2.60 x 10-20