Title: High entropy alloys as plasma facing components in tokamak fusion reactors
Abstract: In the quest for clean energy production, the design and development of safe and reliable thermonuclear experimental systems like ITER, a multi-billion fusion project currently being developed in France, has become paramount to unlocking the immense potential of fusion power as a sustainable and abundant energy source. A critical component in the ITER reactor, the divertor, will face the extraordinary task of extracting the byproducts of fusion, including fast neutrons (14 MeV) and low-energy He+ ions (3.5 MeV), posing unique engineering challenges to overcome.
In this regard, new advanced structural materials with superior irradiation resilience and outstanding tolerance to high heat fluxes (>700°C) should be proposed and developed to preserve the structural integrity and ensure the safe operation of tokamaks. While tungsten (W) is currently the leading plasma-facing candidate, possessing suitable properties such as a high melting point, low tritium (T) retention, and favorable mechanical response, it also comes with inherent challenges. These challenges include intergranular brittle failure due to accumulated He bubbles and the subsequent He bubbles’ growth, susceptibility to neutron-induced swelling and embrittlement, as well as the potential release of tritiated tungsten nanoparticles into the plasma.
Therefore, ongoing research is focused on addressing these limitations and exploring alternative materials. In this study, high entropy alloys (HEAs), a novel class of materials, have been fabricated and tested to mitigate the limitations faced by conventional alloys and pure metals like tungsten in terms of their irradiation response. Due to their unique multicomponent composition that can be tailored to exhibit specific properties coupled with high entropy effect, cocktail effect, as well as sluggish diffusion and lattice distortion effect, high entropy alloys show significant promise for use as plasma-facing components in tokamak fusion reactors.
Biography: Maryna Bilokur is a postdoctoral fellow in the School of Physics at ANU and conducts research on the plasma-facing materials for application in the first wall of the ITER fusion reactor. Her current contributions to the field include the search for new materials with a focus on high entropy alloys resilient to radiation damage when exposed to fusion-like conditions. This project is funded by the Australian Research Council and run by the primary investigator A/Prof Cormac Corr, represents a pathway for Australia to engage with the multi-billion dollar ITER program and enhance the profile of Australia’s nuclear fusion research efforts in pursuit of unlimited clean energy.
In addition to her role at ANU, Maryna serves as a Research Visiting Fellow in the School of Photovoltaics and Renewable Energy Engineering at UNSW. Since joining the team as a postdoctoral fellow in April 2021, she has been involved in research focusing on passive radiative cooling of PV modules.
Maryna Bilokur is recognised as an interdisciplinary researcher. She made significant contributions across different fields, including radiative light transfer, nano-photonics, microfluidics, and materials science. During her tenure at Lawrence Berkeley National Laboratory (Berkeley Lab) in the US in 2020, she focused on modeling and measuring optically scattering systems. During her time in Berkeley Lab, Maryna was one of the pioneers of “Coffee With Postdocs”, which aimed to promote early career researchers. She also served as a Berkeley Lab Science Ambassador, engaging with underrepresented communities to support physics education for primary and high school students.
Maryna earned her B.Sc. (2013) and M.Sc. (2014) Physics and Materials Engineering degrees from Sumy State University in Ukraine. Subsequently, she pursued her Ph.D. studies at the University of Technology Sydney (2015-2019), specializing in novel spectrally selective solar absorbing surfaces for concentrated solar thermal applications. Following the completion of her Ph.D., Maryna joined the nano-photonics team at the University of Technology Sydney (UTS), focusing on the design and fabrication of nano-scale diamond-based optoelectronic devices.
Throughout her career, Maryna has been the recipient of numerous grants and awards, including the ANU Major Equipment Grant (MEC), ANU ICEDs SEED Funding (Institute for Climate, Energy and Disaster Solutions), SPIE PhD candidate travel grant, Study Tours to Poland scholarship (Polish-American Freedom Foundation program), FameLab Australia semifinalist, ARC Discovery PhD Scholarship, UTS PhD President’s scholarship, Academic Scholarship of the President of Ukraine, and DAAD fellowship, enabling her to conduct research in microfluidics at TU Ilmenau in Germany.
11:30 am to 12:30 pm Talk
12:30 pm to 1:00 pm Networking and Light Refreshement
Acknowledgement: This seminar is supported by the Australian Research Council (ARC). The ARC Training Centre in Surface Engineering for Advanced Materials, SEAM, has been funded under Award IC180100005. The additional support from industrial, university and other partners is critical for our success.