Kinetics of helium bubble formation in nuclear materials

Kinetics of helium bubble formation in nuclear materials

The formation and growth of helium bubbles due to self-irradiation in plutonium has been modelled by a discrete kinetic equations for the number densities of bubbles having k atoms. Analysis of these equations shows that the bubble size distribution function can be approximated by a composite of: (i) the solution of partial differential equations describing the continuum limit of the theory but...

Nuclear-Charge Screening in Positronium Formation from Helium Atoms

An analytical treatment of the electron screening effect within an active-electron model is given for positronium formation from helium atoms. A first-order distorted wave approximation with correct boundary conditions is applied to evaluate the transition amplitude. In the range of impact energy for which the introduced perturbative approach is valid, both the total and differential cross sect...

Helium bubble formation in nuclear glass by in-situ TEM investigations

The effect of helium implantation fluences in French nuclear borosilicate glass on He bubble nucleation and growth mechanisms was characterised using in-situ TEM experiments. Observations of implanted glass at 143K indicate that a helium concentration of around 3 at.% is required to nucleate a significant density of nanosized bubbles. He bubble growth is observed for He concentration higher tha...

nuclear-charge screening in positronium formation from helium atoms

an analytical treatment of the electron screening effect within an active-electron model is given for positronium formation from helium atoms. a first-order distorted wave approximation with correct boundary conditions is applied to evaluate the transition amplitude. in the range of impact energy for which the introduced perturbative approach is valid, both the total and differential cross sect...

Nuclear Energy Enabling Technology Enhanced Generic Phase-field Model of Irradiation Materials: Fission Gas Bubble Growth Kinetics in Polycrystalline UO2