NAAREA: Integrating the molten salt fuel cycle into the development and industrialization of the XAMR® microreactor
NAAREA is developing a fast-spectrum reactor technology that uses molten salt-based liquid fuel. Its approach is based on mastering the entire fuel cycle, from salt fabrication to waste transport and management, through to recycling. To help build a dedicated chain, the company is leveraging expertise in chemistry, process engineering, reactor physics and nuclear engineering.
A comprehensive approach to the fuel cycle and related skills
The functioning of molten salt reactors entails a specific supply and processing chain, requiring various technical skills at each stage:
- Fabrication of the coolant salt and fuel salt
This stage relies on experts in molten salts chemistry and process engineering. It involves producing and purifying specific salts, such as sodium chloride (NaCl), magnesium chloride (MgCl₂) or mixtures containing actinides such as plutonium (Pu) and uranium (U) in chloride form. NAAREA is also working on the supply of chlorine‑37 (Cl‑37), an isotope used to reduce the presence of chlorine‑36 (Cl‑36), an approach that aims to limit the production of long-lived waste while improving the reactor’s efficiency.
- Transport and storage of liquid fuel
This phase requires skills in materials engineering, nuclear safety and the logistics of transporting radioactive materials. The storage of molten salts before processing involves specific requirements due to their residual temperature.
- Recycling and management of by-products
The recycling of fuel requires specialists in pyro- and hydrometallurgy processing, capable of extracting reuseable elements while managing final waste.
To structure and optimize the molten salt fuel cycle developed by NAAREA, David Lambertin, Head of the Fuel Cycle Department, oversees several strategic teams:
- Materials, led by Aline Dressler
- Transport, led by Eric Pernice
- Gas and Waste, led by Adrien Rooses Rooses
- Salt Processes, led by Samuel Appert
- Chemistry, led by David Lambertin
- Fuel Project Manager, Raphaele Neveu
A joint laboratory to advance research in molten salts chemistry
NAAREA , the CNRS (the French National Centre for Scientific Research) and Paris-Saclay University joined forces to create a joint laboratory dedicated to molten salt chemistry research: Innovation Molten Salt Lab (IMS Lab). This partnership brings together the expertise of IJCLab (Laboratoire de Physique des 2 Infinis Irène Joliot-Curie), one of the leading European research centres for nuclear physics, and NAAREA’s technological skills to enhance the understanding and development of molten salts applied to fourth-generation reactors.
IMS Lab is part of NAAREA’s efforts to advance applied research in support of the fuel cycle it is developing. The lab’s work focuses on several strategic areas: the synthesis and recycling of fuel salts, purification, the characterization of fission products, and molecular modelling and thermodynamic calculations. Optimizing the operating conditions for the XAMR® microreactor also relies on knowledge in salt chemistry and the behaviour of fission products, in order to refine the design of the reactor and ensure its safety.
The laboratory’s work is carried out in collaboration with Sylvie Delpech and a NAAREA team holding PhDs in molten salt chemistry, all from Paris-Saclay University, and who completed their theses on the subject in Orsay. This expertise is contributing to improving knowledge of the behaviour of salts.
IMS Lab furthermore has specific equipment for conducting experiments, including glove boxes for working with uranium, advanced analysis techniques such as x-ray diffraction (XRD) and inductively coupled plasma (ICP) spectrometry to characterize salts, as well as electrochemical techniques.
Expertise in connection with international developments
NAAREA is developing its expertise in molten salt chemistry through collaborations in the United Kingdom, Germany, Belgium and the United States. These partnerships focus on fuel salts and material behaviour, as well as the specific safety and regulatory issues concerning molten salt reactors. In addition, NAAREA participates in the work of the International Atomic Energy Agency (IAEA) and the OECD Nuclear Energy Agency (NEA), which contribute to structuring the regulatory and technical frameworks for these technologies at an international level. These interactions advance knowledge sharing and the emergence of shared standards for the development of molten salt reactors.
Structuring the molten salt fuel cycle
NAAREA is working to build an industrial sector dedicated to the molten salt fuel cycle, including production, transport, operation and recycling. This process relies on a range of complementary skills in the fields of chemistry, process engineering, reactor physics and nuclear engineering. IMS Lab, the joint laboratory with the CNRS and Paris-Saclay University, contributes essential expertise in salt chemistry and the optimization of salts for industrial applications. In addition, through international collaborations and dialogue within standard-setting bodies, this work is contributing to the development of the sector on a broader level. By developing a comprehensive approach to the fuel cycle, NAAREA is laying the foundations for a sector structured around molten salt reactors and their deployment on an industrial scale.
Photos: Molten Salt Lab (IMSLab) (Source: Lucille Pellerin / Agence Réa)
