Multi-scale Modelling of bcc-Fe Based Alloys for Nuclear Applications
- RMO, SCK-CEN, Mol (Belgium)
Understanding the basic mechanisms that determine microstructure changes in neutron irradiated steels is vital for a safe lifetime management of existing nuclear reactors and a safe design of future nuclear options. Low-alloyed ferritic steels containing Cu, Ni, Mn and Si as principal solute atoms are used as structural materials for current reactor vessels. The microstructural evolution under irradiation in alloys is decided by the interplay between defect formation and thermodynamic driving forces, together determining the appearance of phase transformations (precipitation, segregation,...) and favouring or delaying the nucleation and growth of point-defect clusters, their diffusion and their mutual recombination or removal at sinks. A reliable description of the production, evolution and accumulation of radiation damage must therefore start from the atomic level and requires being able to describe multicomponent systems for timescales ranging from few picoseconds to years. This goal demands firstly the fabrication of interatomic potentials for alloys that must be both consistent with the thermodynamic properties of the system and capable of reproducing correctly the characteristic solute-point defect interactions, versus ab initio or experimental data. Secondly the performance of extensive molecular dynamics (MD) simulations, to grasp the main mechanisms of defect production, diffusion, mutual interaction, and interaction with solute atoms and impurities. Thirdly, the development of simulation tools capable of describing the microstructure evolution beyond the time-frame and length-scale of MD, while reproducing as much as possible the atomic-level origin of the mechanisms governing the evolution of the system, including phase changes. In this presentation the results of recent efforts made in this direction in the case of Fe-Cu, Fe-Cr and Fe-Ni alloys, as basic model alloys for the description of steels of technological relevance, are highlighted. In particular, advanced techniques to fit interatomic potentials consistent with thermodynamics are proposed and the results of their application to the mentioned alloys are presented. Next, the development of advanced methods, based on the use of artificial intelligence, to improve both the physical reliability and the computational efficiency of kinetic Monte Carlo codes for the study of point-defect clustering and phase changes beyond the scale of MD, is reported. These recent progresses bear the promise of being able, in the near future, of producing reliable tools for the description of the microstructure evolution of realistic model alloys under irradiation. (author)
- Research Organization:
- Materials Research Society, 506 Keystone Drive, Warrendale, PA, 15086-7573 (United States)
- OSTI ID:
- 21091560
- Resource Relation:
- Conference: Symposium on Structural and Refractory Materials for Fusion and Fission Technologies, Boston, MA (United States), 28-30 Nov 2006; Other Information: Country of input: France; Related Information: In: Proceedings of the Symposium on Structural and Refractory Materials for Fusion and Fission Technologies, by Aktaa, J. [ed. Forschungszentrum Karlsruhe GmbH, Institute for Materials Research II, Postfach 3640, 76021 Karlsruhe (Germany)]; Samaras, M. [ed. Paul Scherrer Institute, Nuclear Energy and Safety, CH-5232 Villigen PSI (Switzerland)]; Serrano de Caro, M. [ed. Lawrence Livermore National Laboratory, Chemical Biology and Nuclear Science Division, L-632, P.O. Box 808, Livermore, CA 94550 (United States)]; Victoria, M. [ed. Polytechnic University of Madrid, Instituto de Fusion Nuclear, J. Gutierrez Abascal 2, 28006 Madrid (Spain)]; Wirth, B. [ed. University of California-Berkeley, Nuclear Engineering Dept., Berkeley, CA 94720-1730 (United States)], v. 981E, 112 pages.
- Country of Publication:
- United States
- Language:
- English
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