Modelling of High-energy Radiation Damage in Materials relevant to Nuclear and Fusion Energy.
Abstract
The objective through my PhD has been to investigate radiation damage effects in
materials related to fusion and to safe encapsulation of nuclear waste, using Molecular
Dynamics (MD) methods. Particularly, using MD, we acquire essential information
about the multi-scale phenomena that take place during irradiation of materials, and
gain access at length and time-scales not possible to access experimentally. Computer
simulations provide information at the microscopic level, acting as a bridge to the experimental
observations and giving insights into processes that take place at small time and
length-scales. The increasing computer capabilities in combination with recently developed
scalable codes, and the availability of realistic potentials set the stage to perform
large scale simulations, approaching phenomena that take place at the atomistic and
mesoscopic scale (fractions of m for the first time) in a more realistic way. High-energy
radiation damage effects have not been studied previously, yet it is important to simulate
and reveal information about the properties of the materials under extreme irradiation
conditions. Large scale MD simulations provide a detailed description of microstructural
changes. Understanding of the primary stage of damage and short term annealing (scale
of tens of picoseconds) will lead to better understanding of the materials properties, best
possible long-term use of the materials and, importantly, new routes of optimization of
their use. Systems of interest in my research are candidate fusion reactor structural
materials (iron and tungsten) and materials related to the radioactive waste management
(zirconia). High-energy events require large simulation box length in order for the
damage to be contained in the system. This was a limitation for previous simulations,
which was recently shifted with my radiation damage MD simulations. For the first time
high-energy radiation damage effects were simulated, approaching new energy and length
scales, giving a more realistic view of processes related to fusion and to high-energy ion
irradiation of material
Authors
Zarkadoula, Evangelia.Collections
- Theses [4495]