About this Abstract |
| Meeting |
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Symposium
|
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Presentation Title |
Cluster Dynamics Simulations Using Log-Time Stochastic Algorithms to Study Solute Precipitation and Defect Formation in Alloys Under Irradiation |
| Author(s) |
Rohit Vasav, Thomas Jourdan, Gilles Adjanor, Jérôme Creuze, Manuel Athènes |
| On-Site Speaker (Planned) |
Rohit Vasav |
| Abstract Scope |
Predicting the microstructure evolution and ageing kinetics of out-of-equilibrium alloys is an important objective of material science in industrial and nuclear applications. Cluster dynamics, based on solving differential equations for cluster concentrations, allows us to simulate complex systems using stochastic methods (e.g. Gillespie or kinetic Monte Carlo algorithm for rate equations). Here we formulate and propose new stochastic algorithms to quickly and efficiently simulate cluster dynamics equations for large systems. We bypass the linear complexity of the original algorithm by associating an internal time scale to form independent groups of reactions, using priority queues with binary heaps for highly efficient sorting advances. In sparse systems with a weakly-connected reaction network, we create reaction classes based on the underlying diffusing clusters, while conversely for dense systems with a fully connected reaction network, we use a low-rank approximation of the propensity matrices with rejection sampling to significantly reduce the manipulation costs of the queues. In either case, the resulting algorithm exhibits a log-time complexity, capable of reaching physical times and system sizes that were unattainable for previous simulations (deterministic or stochastic) due to a substantial speed-up of several orders of magnitude (compared to the Gillespie algorithm) with considerably less memory consumption than deterministic simulations. As a physical application, we simulate the time evolution of defect clusters and solute precipitation in a FeCu system under irradiation and thermal ageing. The resulting evolution of the distribution and cluster size of Cu precipitates also matches very well with small-angle neutron scattering experiments and theoretical predictions. |
| Proceedings Inclusion? |
Undecided |