Fusion materials

Fusion energy is one of the most promising concepts for energy production, for the increasing need for electricity.

By combining two light elements into a heavier one, energy is released. However, in the same interaction, usually the produced particle/particles will receive a high energy. These high energy particles will degrade the wall and structural materials of the power plant itself. This will both decrease the life-time of the power plant and may cause serious hazards if the consequences are not know. This research is carried out mainly under the EUROfusion project.

In order to predict how the irradiation is affecting both the wall materials and the structural materials in such power plants, computer simulations of the defect production can be carried out with atomistic resolution. On surfaces, parameters like energy, incoming ion type and wall materials can be studied to see how these parameters affect the sputtering of that combination. We have studied all of the proposed wall materials, like W, C and Be, under many different conditions, to investigate their suitability for such environments. In addition to the wall getting affected, the high energy ions and neutrons can easily penetrate deep into the structural materials of power plants. These will also cause damage and affect the mechanical properties on the structural material, like becoming brittle when a high enough irradiation dose is reach, which obviously will have detrimental effects. We have studied both the primary damage production for both conventional materials, like Fe and W, but also complex alloys called high-entropy alloys. Factors like temperature, energy and alloy complexity on the defect production have been studied. In addition to the primary damage in one single irradiation event, massively overlapping cascades have been simulated to achieve higher doses.

Results highlights:

K. Nordlund, J. Keinonen, M. Ghaly, and R. S. Averback, Coherent displacement of atoms during ion irradiation, Nature 398, 49 (1999).

S. A. Norris, J. Samela, C. S. Madi, M. P. Brenner, L. Bukonte, M. Backman, F. Djurabekova, K. Nordlund, and M. J. Aziz, MD-Predicted Phase diagrams for Pattern Formation, Nature communications 2, 276 (2011).

F. Granberg, K. Nordlund, M. W. Ullah, K. Jin, C. Lu, H. Bei, L. M. Wang, F. Djurabekova, W. J. Weber, , and Y. Zhang, Mechanism of radiation damage reduction in equiatomic multicomponent single phase alloys, Phys. Rev. Lett. 116, 135504 (2016), http://www.acclab.helsinki.fi/~knordlun/pub/Gra15andsupplementary.pdf.

K. Nordlund, S. J. Zinkle, A. E. Sand, F. Granberg, R. S. Averback, R. Stoller, T. Suzudo, L. Malerba, F. Banhart, W. J. Weber, F. Willaime, S. Dudarev, and D. Simeone, Improving atomic displacement and replacement calculations with physically realistic damage models, Nature communications 9, 1084 (2018), http://www.acclab.helsinki.fi/~knordlun/pub/Nor17b.pdf.

Senior people involved in this research line:
Prof. Kai Nordlund

Prof. Flyura Djurabekova

Doc. Tommy Ahlgren

Dr. Fredric Granberg

Dr. Alvaro Lopez-Cazalilla

Dr. Jesper Byggmästar