France-based nuclear start-up Naarea (Nuclear Abundant Affordable Resourceful Energy for All) has been working with the European Commission’s Joint Research Centre (JRC) since 2024 on the synthesis of sodium chloride-plutonium trichloride (NaCl-PuCl3) salt to look at safety in the development of liquid fuel for molten salt reactors.
Naarea, founded in 2020 by Jean-Luc Alexandre and Ivan Gavriloff, is developing the XAMR (eXtrasmall Advanced Modular Reactor), a molten salt fast neutron micro-generator (40 MWe or 80 MWt). The company has received support from the French Alternative Energies & Atomic Energy Commission (CEA) and the French National Centre for Scientific Research (CNRS – Centre national de la recherche scientifique) as well as industry players such as Assystem, Dassault Systèmes, Orano and Framatome.
The XAMR design uses sodium chloride (NaCl), in which actinides in the form of plutonium chloride and uranium chloride are dissolved. Naarea says that, in the absence of an industrial sector to supply fuel for these innovative technologies, the synthesis of fuel salt is a key step for validating the project’s feasibility. This involves developing a reproducible synthesis method to produce a pure fuel salt containing fissile materials.
Since 2024, through the Innovation Molten Salt Lab (IMSLab) – a joint laboratory with the CNRS and Paris-Saclay University – Naarea has been working with the European Commission’s Joint Research Centre (JRC) on the synthesis of NaCl-PuCl3. The JRC is the science and knowledge service of the European Commission.
The focus of this collaboration is on validating a proliferation-resistant method of synthesising NaCl PuCl3 salt from plutonium oxide (PuO2), using a pyrochemical process, as well as experimentally determining fundamental data related to this fuel. This method is based on a process that involves bubbling gas through a mixture of NaCl and plutonium dioxide (PuO2), brought to a high temperature using experimental equipment developed and operated by the JRC.
Naarea said that, at laboratory scale, this work demonstrated that bubbling a gas through a mixture of NaCl and PuO2 made it possible to quantitatively dissolve the plutonium oxide and thus form a plutonium chloride-based salt. Additional characterisation stages will follow to confirm the purity of the fuel salt and determine its fundamental properties.
This experimental validation work with plutonium represents an initial step in the fuel cycle strategy, validating the synthesis method’s feasibility and potential. Process engineering and scale-up tests will be carried out, in particular in the short term on simulants of radioactive materials in the experimental facilities of the I-Lab, Naarea’s test facility opened in February in Cormeilles-en-Parisis.
