Nearly two decades ago, Dionysios Chionis first encountered the fundamentals of nuclear energy in a lecture hall at the National Technical University of Athens. What began as an academic interest has since evolved into a clear mission: to reposition nuclear energy not just as a technical solution but as a strategic pillar for Greece’s clean energy transition.

Chionis, with academic credentials from both Greece and Switzerland and experience in the international nuclear sector, isn’t following the trends — he is working to set them. As co-founder of Athlos Energy, he is championing a bold vision: harnessing next-generation nuclear technology not only to power grids but also to decarbonise ships, data centres, islands, and industry, transforming how Greece and Europe think about energy resilience.

In this interview, Chionis discusses bridging research and industry, the overlooked applications of nuclear energy, and why Greece’s unique geopolitical position could turn it into a leader in the energy game — not by following legacy models but by daring to innovate.

What sparked your interest in nuclear energy and led you to reactor physics?

Almost 20 years ago, during my bachelor studies at the National Technical University of Athens, I had the opportunity to hear for the first time the basic principles of nuclear energy. It was at the beginning a simple interest which turned into a real passion. My fascination with nuclear energy began with a deep curiosity about the fundamental forces that shape our universe, but it matured into a mission when I realized nuclear power’s unique potential to deliver large-scale, carbon-free energy. Nuclear technology offers the perfect combination of scientific depth and real-world application.

It is where advanced mathematics and nuclear physics meet the urgent challenge of climate change. During my academic journey both in Greece and Switzerland and later in the international nuclear industry, I was convinced that nuclear energy should and must play a leading role in our energy transition. That conviction ultimately led to co-founding Athlos Energy with Stathis Vlassopoulos, who shares the same urgency and strategic mindset in pushing Greece and Europe toward a more resilient and clean energy future.

You bridge research, industry, and strategy — how do these areas inform each other in your work?

They are inseparable. Research without industrial support can become irrelevant. Industry without innovation stagnates and has no future. And strategy without both lacks vision. At Athlos Energy, we try to connect the continuous developments of new nuclear designs with the strategic needs for clean energy in Greece. People often think that nuclear energy can only be applied on the electrification of the national grid. This is an important aspect, however, nuclear energy can play a vital role in the decarbonization of the maritime sector, in the electrification of data centers and islands, in the desilication of water and last but not list in the clean hydrogen production. All these sectors are relevant for Greece, a small country on the corner of Europe but with a strong geopolitical role. With our initiative, Stathis and myself, open a new market for Greece with great potential for the research communities and industrial sectors.

What’s the biggest public misconception about nuclear energy today?

The most persistent misconception is that nuclear energy is inherently unsafe and outdated. In reality, nuclear energy is among the safest energy sources, statistically and technologically. People often equate nuclear energy with past accidents and nuclear weapons development, ignoring decades of the excellent performance of hundreds of nuclear reactors worldwide and the constant safety evolution behind the design of modern reactors. The other major misconception is that nuclear is too slow or expensive to be part of the climate solution — yet Small Modular Reactors (SMRs) and advanced reactors are designed precisely to address these concerns.

Public perception is changing, but we need to accelerate that shift through better communication and education. This public opinion has also been observed in Greece. The latest survey in 2024 by the European Commission indicates that 43% of the Greek public shares positive opinions about the effect of nuclear energy on energy production. This is a change that we have also observed personally at Athlos Energy by participating actively in various workshops and events over the last months.

People with different backgrounds and beliefs approach us and express their interest in nuclear energy and very often state a very simple question; “Why Greece doesn’t yet have a nuclear energy program?”. With Stathis we took the initiative to create Athlos Energy to inform the Greek public about the advantages and challenges of nuclear energy and to answer this key question from the public. We are formed with the clear goal to plan, initiate and execute the first Greek nuclear project.

How close are we to seeing Small Modular Reactors deployed at scale?

Closer than many think — but challenges remain. Some SMR designs are under regulatory review, while others are already approved or under construction in North America, Europe, and Asia. In the Western, we might see the first SMR constructed by General Electric operational in Ontario before the end of this decade. If this first example is successful in terms of time schedule and cost prediction, then I believe that the SMR market will phase a significant acceleration in the US and Europe in the next decade.

What we need now is a coordinated political will, streamlined and harmonised licensing across the different regulators, and integrated financing models. In Greece, we are advocating for the creation of a nuclear roadmap that includes SMRs, among other options, as a strategic solution for decarbonising the industry and securing our grid flexibility. Deployment at scale could happen within the next 5–10 years, but only if governments act now to prepare the ground.

How can international collaboration enhance nuclear innovation and energy security?

The nuclear industry has a long history of several decades. When we look back, we can easily understand why our industry had its glory days in the 70s and 80s because of cooperation. No single country holds all the expertise, and global challenges require shared solutions. Today, we need the same recipe to succeed. Through partnerships in research and development, joint licensing frameworks, and structured supply chains, collaboration accelerates innovation while lowering risks for the investors. Greece, for example, could embark on nuclear by partnering with countries already developing SMRs or advanced reactors. Alternatively, Greece could collaborate with our neighbours who are very active in the nuclear industry, such as Italy, Bulgaria, Turkey, Romania, and very recently, Egypt and Serbia.

At Athlos, we are actively engaging with global players and international stakeholders to build these bridges. Energy security today is about alliances — not isolation and willingness to explore all possible solutions. Without any doubt, we must very consciously have the courage to put the nuclear topic on the table of discussion. We should not lose the momentum of the global nuclear renaissance for the second time and remain isolated from this technology.

Where does nuclear best fit within national clean energy strategies, especially in renewable-heavy countries?

Nuclear complements renewables. If we want to succeed, we have to use all clean energy sources to achieve the national and global energy and climate goals. While solar and wind are vital, they are intermittent by nature. Nuclear provides the stable, low-carbon baseload that fills the gaps — and does so without emitting CO₂ or any other greenhouse gases. In countries like Greece that enjoy high solar potential, nuclear ensures energy sovereignty during nights or winters. It also enables the decarbonisation of hard-to-electrify sectors like heavy industry or shipping through clean hydrogen and heat applications. The future energy mix must be diverse, and nuclear is the anchor that makes it work reliably.

The first step to start exploring the option of nuclear energy is for the Greek government to add nuclear energy as an option in its National Plan for Energy and Climate until 2050. This is our greatest milestone for the next few years: to launch a comprehensive analysis highlighting the advantages of nuclear energy for the Greek State, with the aim of convincing the Greek Government to reconsider its energy strategy.

Tell us about your current role and how your company contributes to advancing nuclear energy.

Athlos Energy is the first Greek start-up in the nuclear energy industry, which was formed in September 2024 by Stathis Vlassopoulos and me. Both we are Greek nationals with studies in mechanical engineering and nuclear physics in Greece and Switzerland. We have a long experience in the international nuclear industry and we have developed a very strong global network, which position us at a focal point for the development of the first nuclear project in our home country. Our initiative is purpose driven; we want to help our country achieving its energy and climate ambitious goals by exploring the alternative solution of nuclear energy.

Together with Stathis, we are very vocal, trying to inform the public about nuclear energy and how this technology can support the Greek community and the Greek economy. We work on feasibility studies, technology assessments, and ecosystem-building efforts with global developers and Greek stakeholders. Our role is to unlock political, economic, and social momentum for a nuclear-inclusive future. In this journey, we search for partners who share the same concept and want to contribute to achieving a greater goal.

What’s your vision for the future of nuclear energy in Greece? Do you see realistic pathways for its development?

Absolutely. Greece has all the prerequisites: a high-tech industrial base, growing energy demands, geopolitical position, and a strong academic tradition with exceptionally bright people. Our vision is for Greece to establish its first nuclear program while creating a completely new market. With the right alliances and strategic vision, we can have operational nuclear capacity within a decade. This is not science fiction — it’s a national opportunity. But it requires decisive steps today: regulatory preparation, public engagement, and political alignment.

Let me highlight that we are not global pioneers; the Estonian start-up company Fermi Energia started the same journey five years ago, and very soon, they will be ready to construct the first-ever nuclear reactor in their country.

Are current regulations keeping up with nuclear innovation? What needs to change?

Unfortunately, not fast enough. Many regulatory frameworks were designed decades ago for large, conventional reactors and, in some areas, are not already applicable for SMRs or further advanced reactor concepts. On an international level, there is great work to harmonise and standardise the regulatory regimes of the new technologies. There is open communication between the nuclear technology developers and the regulatory bodies. At Athlos Energy, we have the opportunity to regularly exchange information about the progress of our project with the Greek Atomic Energy Commission by understanding what the necessary steps are for them if Greece decides to enter the nuclear era. At the same time, in April 2024, we had the unique chance to visit the International Atomic Energy Agency in Vienna and learn the best practices allowing the regulatory bodies to be ready for nuclear innovation, especially for new nuclear-embarking countries.

What role do AI and digital tools play in reactor safety and efficiency?

Artificial Intelligence has been transforming the nuclear industry since the beginning of this decade. From predictive maintenance to real-time anomaly detection and digital twins for virtual reactor modelling, these tools drastically improve both safety and efficiency. Many operational nuclear reactors introduce AI tools in their daily work, and new SMR designers use AI to help automate control systems, reduce human error, and streamline plant diagnostics. Today, digital technologies is a way making nuclear more accessible and cost-competitive. Combining physics-based models with machine learning techniques could be one of the next great breakthroughs in the field.

What advice would you give to young professionals entering the nuclear field?

Stay curious, stay bold and think systemically. Stathis and myself had the great opportunity to learn the first principles of nuclear physics alongside talented Professors at the National Technical University of Athens who shaped our characters. We decided to move to Switzerland to advance our knowledge by knowing that to follow our dream, we would have to leave our country and our families. In the nuclear sector you will find always professionals which are purpose driven and they want to contribute with their work to a better future for our planet and for our kids.

The nuclear sector doesn’t need only physicists and engineers but also communicators, economists, software developers, advocates and policymakers. The next generation of nuclear leaders will be interdisciplinary, mission-driven, and globally minded. Build a strong foundation in science, but never lose sight of the broader societal impact.

Together with Stathis we made a bold decision to initiate a dialogue about a topic which was out of the question for decades. It needs some courage to make the first steps toward something greater than us.