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The Group

Steven Zinkle
Governors Chair Professor

Steve Zinkle joined the University of Tennessee as a Governor’s Chair Professor in October, 2013. He previously worked at Oak Ridge National Laboratory in a variety of research and technical management positions. His research interests are centered on the design and advanced manufacturing of structural materials, microstructural evolution and radiation effects in metallic and ceramic materials for fusion and fission energy systems, deformation mechanisms in structural materials, space nuclear reactor materials, and plasma-materials interactions in fusion energy systems. His hobbies include jogging and basketball.

Research Scientists

Shradha Agarwal

Shradha Agarwal received a PhD in nuclear material science from the French Energy Atomic Commission (CEA-Saclay) based near Paris, France in 2014. In 2015, she joined Tata Steel R&D at UK as a staff scientist where she worked on various steel metallurgy industrial research projects and also led the national level R&D project on ‘identifying the application of steels for future energy plants in UK’. In 2017, she returned to academics and is now working as Research Scientist in the Department of Nuclear Engineering, UT-Knoxville. Her main research interests include studying radiation effects in metallic and ceramic materials for fusion and fission reactor applications using state-of art experimental tools. In her personal time, she enjoys swimming and traveling. 

Postdoctoral Research Associates



Siwei Chen joined the University of Tennessee as a Post-Doctoral Research Associate in September, 2022. She previously worked at Central Research Institute of Electric Power Industry as a Visiting Researcher. She received a Ph.D. in the field of materials science and engineering from Hokkaido University in 2014. Her research interests include irradiation damage of structural materials in fission and fusion energy systems, advanced electron microscopy techniques, and atom probe tomography techniques. Outside of working, she likes spending time outdoor with family and friends.

Graduate Researchers



Ty Austin

Ty grew up in a small town in Missouri. He received his bachelor’s degree from the University of Arkansas in Chemical Engineering. His research focuses on how precipitate-strengthened iron alloys are produced using advanced manufacturing techniques with a focus on additive manufacturing. Ty’s hobbies include playing board games with friends and family and being a whiskey and craft beer geek.

Kacie Breeding

Kacie is from a small town in rural Middle Tennessee. She graduated with her bachelor’s degree in Nuclear Engineering from the University of Tennessee in 2017. She is currently working towards her Ph.D in Nuclear Engineering/Material Science at University of Tennessee in Dr. Zinkle’s research group. Her research focuses on hydrogen isotope permeability in materials for potential use in tritium extraction devices for fusion reactors. Outside of academics, she loves music and concerts, videogames, and her pet cats and reptiles.


Qinyun Chen

Qinyun Chen grew up in Shanghai, China. She received her Bachelor’s degree in Nuclear Engineering from Fudan University. She is interested in the radiation effects in structural materials. She works on the radiation induced disorder and amorphization of intermetallics recently. In her spare time, she loves to watch romantic TV shows.

Zehui Qi

Zehui Qi is from Shanghai, the most populous city in China. She got her Bachelor’s degree in nuclear science and technology from Fudan University. She is interested in radiation effects in metals and ceramics such as microstructural evolution in irradiated SiC/SiC composites. In her spare time, she enjoys hiking and music

Emily Proehl

A Wisconsin native, Emily obtained a Bachelor’s degree in Materials Science and Engineering (MSE) from the University of Wisconsin-Madison in 2019. Emily joined Dr. Zinkle’s group to pursue a Ph.D. in MSE and explore the intersection of materials with nuclear power. Her primary research interests are radiation damage and mechanical properties, and she looks forward to generating a thesis topic. In her free time, Emily enjoys baking, knitting, and the great outdoors. 

Ryan TheirRyan Thier

Ryan Thier is a PhD student from the Chicago area. After graduating from the University of Illinois with a B.S. in Materials Science and Engineering in 2016, he worked as a metallurgist in the aerospace industry before joining Nuclear Engineering at Tennessee. He is interested in structural alloy development for both fission and fusion applications. He enjoys hiking and reading, and is a member of Citizen’s Climate Lobby

Mediha Merve Karatas

Mediha Merve Karatas is a PhD student in the Nuclear Engineering Department at the University of Tennessee, Knoxville. Before joining Prof. Zinkle’s group, she received her Bachelor’s of Science in Physics from Middle East Technical University (METU), Turkey. She received Master of Science Degree in Metallurgical and Materials Engineering from METU. She also received Master of Science Degree in Nuclear Engineering and Engineering Physics from University of Wisconsin, Madison. She was interested in physical metallurgy and studied in Novel Alloys Design and Development Laboratory (NOVALAB) in METU. Her thesis title is ”Synthesis and Characterization of Bulk Amorphous/Nanocrystalline Soft Magnetic Materials”. In UW, Madison, her graduate research focused on characterization capabilities using XRD/EDS/SEM tools to explore the many compositions of High Entropy Alloys for nuclear reactors, especially the ones being generated by high-throughput synthesis.

Sydney Copp

While Sydney was born and raised in Vancouver, Canada, her family now resides just outside of Washington DC. Sydney recently graduated from the University of Tennessee with a B.S. in nuclear engineering in May 2021, and is joining Dr. Zinkle’s research group to pursue her Ph.D. in the same. Sydney is most interested in radiation effects in materials for advanced reactors. When she is not working, she enjoys reading, baking, and indoor cycling.

July Reyes Zacarias

July was born and raised in the Dominican Republic, where she earned her bachelor’s degree in physics from the Autonomous University of Santo Domingo (UASD). Before joining Dr. Zinkle’s research group, she worked in the education and nuclear sector. Now, she is pursuing a Ph.D. in Nuclear Engineering and a Master’s degree in Materials Science and Engineering at the University of Tennessee. Her current research is on additive manufacturing techniques for extreme environmental conditions such as nuclear power. Outside of work, July enjoys spending time with her loved ones and traveling. She also knows three languages and is learning the fourth one.

Alex Nadermann

Alex Nadermann grew up in Redmond, Oregon, a small town in Central Oregon. He received a B.S. in Engineering and B.S. in Physics at Northwest Nazarene University in Nampa, Idaho, while competing in the NCAA Division II Men’s Soccer program. He joins Dr. Steven Zinkle‘s group in the Fall of 2022 as a Ph.D. student. His interests include fuel materials for nuclear thermal propulsion and small modular reactor technologies. His hobbies include hiking, fishing, and spending time outdoors with his wife and their golden retriever.

Jonas Kessing

Jonas Kessing graduated from North Carolina State University with a B.S. in Mechanical Engineering. He worked as a Reactor Operations Engineer for the Naval Nuclear Laboratory and a Fuel Process Engineer for Nuclear Fuel Services (BWXT) before joining Dr. Zinkle’s group to pursue a Ph.D. in Nuclear Engineering and a Master’s degree in Materials Science and Engineering. He is interested in fuel materials used for nuclear thermal propulsion and next-generation reactors. He enjoys playing basketball, cooking, and spending time with his wife and daughter.


Thomas Siggillino

Thomas is a PhD student from Pennington, New Jersey. He received his BS and MS in Materials Science & Engineering from Lehigh University before joining Dr. Zinkle’s group in the Fall of 2022. He is interested in materials tolerant of intense radiation and other extreme environments relevant to advanced fission reactors, particularly those that can be additively manufactured. Outside of work he enjoys learning languages, baking, rock climbing, and choral singing. 


Maegan Lenertz

Maegan Lenertz is a PhD student pursuing an Energy Science and Engineering degree in the UTK Bredesen Center for Interdisciplinary Research. Maegan obtained her undergraduate degree from Embry-Riddle Aeronautical University in 2023, studying Mechanical Engineering with a specialty in Robotics. Maegan’s research in the Zinkle group will be focused on irradiation effects in next-gen reactor alloys manufactured with additive methods. In her free time, Maegan enjoys doing just about anything outdoors, especially hiking and horseback riding. She also enjoys spending her time drawing, painting, and embroidering.

Luke Hansen

Luke Hansen graduated from Louisiana Tech University with a B.S in Mechanical Engineering. He worked as a Mechanical Design Engineer testing subsea equipment with Schlumberger for 3 years before joining Dr. Zinkle’s group in the Fall of 2023. Luke’s research interests lie in creating nuclear materials for extreme environments such as Nuclear Thermal Propulsion, and he is pursuing a Ph.D. in Nuclear Engineering with a Master’s in Material Science. Some of Luke’s hobbies include triathlons, hiking, learning music, reading biographies, writing, and game nights with friends.

Ethan Payne

Ethan Payne graduated from Wake Forest University with a B.S. in Physics, and joined Dr. Zinkle’s group in the fall of 2023 to pursue a PhD in Nuclear Engineering and a Master’s Degree in Materials Science and Engineering after gaining interest in the fields while researching radiation and spaceflight effects on biological tissue in undergrad. He is interested in nuclear fuels and materials for application in nuclear thermal propulsion. Outside research and classes, he enjoys exploring the outdoors, reading, and finding a good coffee shop. 

Josina “Wilna” Geringer

Josina Geringer, or “Wilna” as everyone knows her, is a PhD student in the Nuclear Engineering Department at the University of Tennessee. She grew up in South Africa, where she obtained a Bachelor’s degree in Industrial Engineering at the University of Pretoria as well as a Master’s degree in Nuclear Engineering at North-West University in Potchefstroom. As a junior engineer she started her career working on South Africa’s Pebble Bed Modular Reactor (PBMR), a high temperature reactor concept. This triggered her research interest in advanced reactors. Her more recent experience involves managing HFIR irradiations programs, where she is involved with fusion reactor and materials research. Her current interest and focus is on advanced nuclear materials under extremes. Besides travelling and spending time with loved ones, she enjoys the outdoors and quiet time in nature.

Maxx Jackson

Maxx Jackson is an R&D Scientist with a background focused on researching and developing manufacturing solutions for nuclear and nuclear related materials. He spent six years exploring various processing and fabrication methods of refractory ceramics and metals for pilot and demonstration scale applications in the nuclear security enterprise at the Y-12 National Security Complex and two years working with TRISO-X, LLC to help improve their fuel element fabrication capabilities. He holds a B.S. in Biochemistry from Claflin University, and an M.S. in Physics, concentrating in Materials Science from Alabama Agricultural and Mechanical University. His pastimes include spending time with his wife and their children, listening to formal debates, playing the violin, producing music, star gazing, and learning about anything dealing with space. His favorite quotes are “To whom much is given, much will be required.” (Luke 12:48) and “You can’t solve a problem you’re not willing to have” – Dave Evans. Maxx is currently interested in the irradiation effects of radiation resistant materials and developing advanced materials that can be used under extreme conditions.