In order to examine influences of coexistent hydrogen isotopes on diffusion behavior of tritium in niobium, tracer diffusion coefficients Dtof tritium in alpha phase of hydrogenated and deuterized niobium (α-NbHxTyand α-NbDxTy(x<0,8, y<<x)) have been measured at 473 K, 493 K and 553 K. The data on Dtshow typical hydrogen concentration dependence: Dtof tritium for both α-NbHxTy, and α-NbDxTy, decreases with hydrogen concentration under all experimental conditions. The obtained concentration dependence of Dtof tritium differs from that of Dtof protium in α-NbHxor of deuterium in α-NbHxTy. On the other hand, no appreciable differences in the concentration dependence of Dtof tritium between α-NbHxTy, and α-NbDxTy, are observed: there are no definite isotope effects due to the coexisting hydrogen isotopes. This result suggests that Dtof tritium for a tritiated niobium (α-NbTx) is not very different from that for α-NbHxTyand α-NbDxTy. The chemical diffusion coefficient D* of tritium is also evaluated on the basis of the obtained Dtof tritium and of a literature value of a thermodynamic factor F for Nb-H and Nb-D systems.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Nuclear Energy and Engineering