In a nutshell:
After completing her undergraduate degree in South Korea, Suneui (Soni) moved to Japan to pursue an advanced degree in fusion energy technology. After receiving her PhD, she began work at Kyoto Fusioneering (KF) in April 2023 and is now working on developing storage systems for our fusion fuel cycle systems.
Can you tell us more about your work at Kyoto Fusioneering (KF)?
I’m part of the Tritium Technologies Team in the Fuel Cycle Department, where we focus on fusion fuel cycle system R&D.
I’m mainly working on a “storage system” designed to safely store deuterium and tritium (D-T), which serve as the fuel for fusion reactions. I’m also looking into hydrogen storage alloys.
For fusion projects like ITER (International Thermonuclear Experimental Reactor), uranium is typically used for storage. Since using uranium means a stringent compliance protocol and detailed reporting procedures, KF is exploring the possibility of using a zirconium-cobalt (ZrCo) alloy instead. That said, ZrCo-based storage systems face a unique challenge compared to uranium: their crystalline structure becomes deformed and deteriorates when used.
My experiments focus on finding a viable solution by developing a storage system that optimizes ZrCo’s unique properties. It’s an ongoing process of trial and error to develop a more durable, high-performing storage system.
As you research hydrogen storage technologies, what challenges have you faced, and what keeps you motivated?
One of the biggest challenges is creating the right experimental conditions. To accurately compare experimental results, we need to ensure similar conditions across all elements except the one being studied.
Since fusion fuel cycle system is incredibly intricate, with multiple interconnected devices, we need to find a way to ensure compatibility between components and carefully consider their placement within the experimental setup. Even minor differences, like the angle or height of equipment, can lead to significant variations in results.
At first, I would often spend too much time preparing for an experiment. That said, as I gained experience, I started picking up tips and hacks, like how to attach gaskets easily or how to ensure the optimal height and angle for certain pipes.
This has made preparations smoother, giving me more time to focus on the actual experiments. I feel a sense of satisfaction when I see how I’ve grown through this process.
Another highlight came in November last year when I presented my experimental findings on storage systems at the 41st Annual Conference of “The Japan Society of Plasma Science and Nuclear Fusion Research.”
It was really gratifying to discuss ZrCo-based R&D with a professor who mentored me in graduate school. I felt really proud to be able to showcase how much I’ve grown at KF. I also received very helpful advice on experimental methods from other professors, making it a truly memorable experience.
Looking back on your studies into fusion energy, what inspired you to leave South Korea for Japan?
I’ve always been interested in chemistry, particularly the energy sector. In school, I spent time exploring different ways to produce energy and started wondering, “Is there a way to generate abundant energy with minimal risk?”
Around that time, I met a fusion energy researcher by chance at a kendo martial arts studio where I often practiced. He explained the principles and potential of fusion energy, which instantly captured my interest because it would be the answers to the questions I had.
Through these conversations, I learned that research on fusion fuels is highly dynamic and promising, and Japan has excellent graduate programs specializing in this area.
Since I love taking on new challenges, I decided there and then to pursue my graduate studies in Japan. While I hesitated a little to leave my family to study abroad, my curiosity far outweighed my fears. At the time, I wasn’t fluent in Japanese, so I joined introductory Japanese language classes with younger students at my university.
Although the deadline was tight, thanks to the support of my professors and hard work, I managed to reach the required language proficiency needed to submit my application.
What did you research at grad school?
During my master’s and doctoral programs, I worked on a project related to ITER: “Tritium distributions in castellated structures of Be limiter tiles in JET-ITER-like wall vacuum vessels.” As part of the project, I analyzed the relationship between materials and tritium levels using components from The Joint European Torus (JET) (more details can be found in this blog post in Japanese).
This project gave me key foundational knowledge on fusion fuels that I can now leverage at KF as I develop fusion fuel cycle system.
Since the ITER components contained tritium, we needed to visit specialized facilities, like the ITER-BA facilities in Aomori (northeast Japan) and VTT Technical Research Centre in Espoo, Finland. I was fortunate to be able to travel frequently and collaborate with researchers worldwide. While communicating with others from different cultures and backgrounds was sometimes challenging, it was also a great learning opportunity. These experiences have proven helpful when working with team members across five global locations with diverse backgrounds at KF.
What motivated you to join KF?
Fusion energy research has always been deeply fulfilling for me, so I wanted to remain in Japan after earning my PhD and find work in this field.
While looking into labs and startups focused on fusion energy, my professor suggested KF since I would be able to work in a dynamic, multinational environment.
As I started to look into KF more, I discovered that researchers who I really respected, like Dr. Konishi our CEO and Dr. Mukai, work at KF. The fact that these experts in fusion energy were at KF convinced me that this would be the ideal place to gain expertise and build my career, so I applied through the company’s website.
I was excited to receive the offer and to think about the many opportunities that awaited me at KF.
Since you started working at KF, has the organization met your expectations as a place to develop and grow as a researcher and professional?
Absolutely. In my team, many of my colleagues are experienced engineers and researchers, and I’ve learned a great deal from them through my day-to-day work.
Everyone here leverages their strengths to advance fusion fuel cycle technologies while actively sharing their expertise. This collaborative spirit extends beyond our team—it’s in the DNA of our Plant Technology Division and a key part of KF’s company-wide culture.
Since fusion fuel cycle system encompasses interconnected systems, such as exhaust systems (divertors, pumps, DIR systems) and separation technologies (impurity removal, isotope separation), sharing knowledge across teams ensures that we optimize our experiments to better align with other systems, which I find incredibly helpful.
KF has recently opened its second R&D facility to conduct experiments on individual components and systems related to the Fusion Fuel Cycle System. How do you think this will change your work?
Previously, fuel cycle R&D was spread across multiple locations. By consolidating research at the “Tokyo Ryutsu Center (TRC)”, we’ve brought all system components under one roof.
Through this new R&D facility, we can conduct more integrated experiments and accelerate technological development by testing the interaction between systems, such as connecting a Pd diffuser to a vacuum pump to transport hydrogen and impurities. Having team members work together in one location enhances collaboration and efficiency, thereby creating a more productive environment for R&D
Last question…what do you hope to achieve at KF?
This year, I’ll start simulating transport systems surrounding the storage system I’ve been working on. Through these simulations, I hope to finalize an efficient design for fuel storage systems. I’m really looking forward to taking on this new challenge.
In the long term, I plan to contribute to other aspects of fusion fuel cycle system and further expand my expertise. Ultimately, I’d like to use my technical knowledge and skill set to build an actual fusion power plant and make a meaningful impact in this field.
