Thorizon and TNO Launch Materials Programme for Molten Salt Reactors

The programme will directly support the licensing of Thorizon’s PIONEER demonstrator in Petten and the commercial rollout of Thorizon One. Thorizon and TNO plan to collaborate with other organisations in the Dutch nuclear sector, including Delft University of Technology and NRG PALLAS. They also aim to involve international partners, such as the French Alternative Energies and Atomic Energy Commission (CEA) and the European Commission’s Joint Research Centre (JRC).

Why the next generation of nuclear matters

Europe needs clean electricity around the clock. Electrification, industrial growth and AI infrastructure are increasing demand on grids that are already under pressure. Wind and solar will supply a large share of Europe’s electricity, but reliable sources that operate day and night will also be needed. The Netherlands plans to develop 7 GW of nuclear capacity by 2050, including small modular reactors that can supply industrial sites and data centres directly.

Molten salt reactors are a promising new reactor technology, offering low-pressure operation, enhanced safety, efficient fuel use and the potential to reduce long-lived radioactive waste. Turning that potential into operating reactors, however, requires robust evidence of how materials behave in molten salt at high temperatures over time. This evidence is needed to support licensing, determine reactor lifetimes and enable commercial deployment.

Solving the materials challenge by design

A central challenge for molten salt reactors is ensuring that structural materials can withstand hot, corrosive salt and radiation for many years. Thorizon addresses this challenge through its cartridge design. The fuel salt is contained in sealed cartridges that are replaced after five to ten years, limiting the exposure of key components to the salt and enabling their inspection and replacement during scheduled cartridge changes.

The design provides a practical way to manage material degradation, but it must be supported by evidence. Regulators and operators need to know how materials behave under the temperatures, chemical conditions and radiation found inside the reactor. This programme will generate the data and models needed to confirm design choices, determine cartridge lifetime and monitor materials during operation.

From laboratory to industrial qualification

TNO has extensive experience in materials research, testing and modelling. Its work includes material characterisation, corrosion testing, failure analysis, coatings and lifetime prediction. TNO investigates whether the chosen materials are suitable for use in reactors.

The partners have begun defining the research and testing plan. This will be followed by an extensive programme of materials characterisation, corrosion testing, modelling and validation. Initial work is under way at Thorizon’s facilities in Amsterdam and TNO’s laboratories in Petten, directly supporting Thorizon’s reactor design, material selection and licensing process.

A Dutch programme with international reach

Thorizon and TNO plan to work with other organisations in the Dutch nuclear sector, including Delft University of Technology and NRG PALLAS. They also aim to involve international partners, such as the French Alternative Energies and Atomic Energy Commission (CEA) and the European Commission’s Joint Research Centre (JRC). These organisations could contribute expertise in materials, molten salt chemistry, irradiation, modelling, reactor engineering and licensing.

The programme comes as the Dutch government increases its support for nuclear energy, including funding for advanced reactors through the nuclear IPCEI. It will connect Dutch research institutes, universities and industry with European partners, building the knowledge and testing capacity needed to bring advanced reactors to market.