Diffusion of sodium, potassium, calcium, manganese, and radon in tuff and clinoptilolite under leaching

Nuclear physics methods are used to determine the diffusion coefficients of Na, Ca, Mn, K, and $^{222}$Rn in clinoptilolite (Sokirnitsa occurrence, Ukraine) and in natural tuff (Yucca Mountain, Nevada, United States) and in tuff irradiated by $\gamma$-quanta ($E_{\mathrm{max}}$ = 23 MeV) to a dose of 10$^7$ Gy at a leaching temperature of 37$^\circ$C. The diffusion coefficients of sodium and potassium in clinoptilolite are found to differ considerably: 4 $\times$ 10$^{-17}$ and 2 $\times$ 10$^{-20}$ m$^2$/s, respectively. This indicates the influence of aquacomplexes on the cation transfer. The diffusion coefficient of radon in these materials is determined: in clinoptilolite it equals 2.5 $\times$ 10$^{-12}$ m$^2$/s.