Amsterdam, March 18th, 2026 Thorizon, a European deep-tech scale-up developing next generation molten salt reactor technology, today announced the appointment of Antoine Claisse as Chief Technology Officer. His appointment strengthens the company’s technical leadership as Thorizon accelerates reactor design, validation and licensing. Founder Sander de Groot will transition to Chief Science Officer, focusing on R&D partnerships, intellectual property and key technology challenges.

Technology Leadership for the Next Phase of Reactor Development

As Chief Technology Officer, Antoine Claisse will lead Thorizon’s core technical disciplines including reactor physics, mechanical engineering, chemistry and reactor architecture, while overseeing the company’s technology validation program. He will guide the technical analyses and validation activities that underpin the reactor design and its progression toward licensing.

Antoine brings deep experience from complex nuclear programs, including responsibility for nuclear safety and licensing activities at the ITER fusion project, and from roles at leading nuclear institutions such as CEA and IRSN. He is known for his structured systems thinking and pragmatic approach to engineering tradeoffs, helping multidisciplinary teams make technical decisions clear and actionable.

“Antoine is one of the most structured and driven leaders I have worked with,” said Kiki Lauwers, CEO of Thorizon. “He combines exceptional technical depth with a rare ability to bring clarity and structure to complex engineering challenges. In a first of a kind nuclear program, where technical decisions directly influence licensing, timelines and cost, that ability is invaluable. I am incredibly excited to have him leading our technology organization.”

“I am very pleased to take on this role at such an important moment for Thorizon. Molten salt reactors will play a key role in the future energy system, thanks to the advantages they offer in terms of safer energy production and their potential to play a major role in the nuclear fuel cycle. And Thorizon’s innovative cartridge concept is the key factor in ensuring the rapid development of this game-changing technology. Turning that potential into a deployable technology requires rigorous engineering and close collaboration across disciplines. After my first two years here at Thorizon, I know that Thorizon brings together the strong scientific expertise, the pragmatic engineering approach and the perfectly suited team to make this technology a reality. And it is a real honor to be part of this journey in this role,” said Antoine Claisse, Chief Technology Officer of Thorizon.

Founder Focus on R&D and Partnerships

Sander de Groot, founder of Thorizon, will transition to the role of Chief Science Officer. Sander is the inventor of Thorizon’s molten salt reactor concept and author of the core patents that underpin the technology. Since founding the company as a spin off from NRG, he has laid the groundwork for the development of a new generation of molten salt reactors.

As Chief Science Officer, Sander will focus on advancing the technology and strengthening collaborations with leading research institutes, universities and international partners. He will continue to develop Thorizon’s intellectual property and tackle the toughest technical questions behind the reactor concept, areas where the team regularly turns to his expertise. In this position he will also play a leading role in engaging with investors, partners and the broader nuclear community, sharing the vision behind molten salt reactors.

“Sander is the inventor of the reactor concept at the heart of Thorizon and one of the deepest experts in molten salt reactors,” said Kiki Lauwers, CEO of Thorizon. “His ability to crack the most complex technical and scientific challenges and turn them into practical solutions has been fundamental to building the company. As Chief Science Officer he will be able to focus even more on advancing the science, strengthening R&D partnerships and sharing the vision behind this technology with partners, investors and the broader nuclear community.”

“It has been incredibly rewarding to see the reactor concept grow from an idea into a company with such a talented team working on it,” said Sander de Groot, Founder and Chief Science Officer at Thorizon. “I am excited to spend more time on the toughest technical challenges behind the concept and on the partnerships that will help bring molten salt reactors to reality. I look forward to continuing to support the team and sharing the potential of this technology with the broader nuclear community.”

Building a future proof Technology Organization

The strengthened leadership structure reflects Thorizon’s transition toward a more integrated engineering and design phase, working closely with industrial partners and leading R&D institutes and academia. In their respective roles, Laure Claquin as COO, Antoine Claisse as CTO and Sander de Groot as CSO will ensure strong alignment between engineering development, system and safety analyses, validation and external partnerships.

By combining deep nuclear expertise with pragmatic engineering and strong industrial collaboration, Thorizon is building the capabilities needed to bring a new generation of nuclear technology from concept to deployment in Europe.