  Helium bubbles nucleation and growth in metals or metal tritide is a
long-standing problem attracting considerable attention in nuclear industry but
the mechanism remains indistinct and predicting the growth rate of helium
bubble is inexistence still up to new. Here, the rate of helium bubbles
nucleation and growth in metal tritide is developed based on a dynamical model,
which describes the diameter of helium bubbles increasing linearly as t**(1/3)
in titanium tritide at room temperature, agreeing quite well with the
experimental phenomenon. The way of reducing storage temperature from 300 to
225 K or increasing the helium atoms diffusion barrier from 0.81 to 1.1 eV can
effectively restrain bubbles growth and prolong lifetime of titanium tritide
more than 4 times, which provides a useful reference to relevant experiment
exploration and applications. This model also can be used to predict lifetime
of new tritium-storage materials and plasma facing materials in nuclear
industry.
