LNER Research Activities

Nanomaterials for nuclear energy

Recent advances in the synthesis of textured materials have been used to develop specific materials with typical sizes of a few nanometers to hundreds of nanometers. It was thus possible to show that the properties of these materials were modified and, in some cases, improved. We find these nanomaterials in many fields of research (such as catalysis, sensors). The tasks of this lab are exploring this path for future nuclear materials, and to characterize its nature, reactivity, and evolution in time.

The objective of this research is to use the knowledge gained on matter self-transformation at all scales and associated physicochemical changes to design innovative functional materials for future energy, and nuclear power in particular. A key point to understand these behaviors is based on the development of methods capable of correlating and expand our knowledge of phenomena at the interface to the properties at mesoscopic and macroscopic scales.

These skills can be applied in several topics:

  • For instance, the emergence of matrices with organized meso / nanostructure is very attractive for waste conditioning topic. Indeed, the development of new forms of radionuclides storage by nanoscale encapsulation (as mesoporous materials, nanocomposite and / or multiphasic aggregates), in alternative to the atomic substitution in the common ceramic or glass matrices is studied in this team.
  • This approach can also be applied to the case of developing innovative solutions for the extraction of actinides or for the decontamination of radioactive effluents. In this case it is the use of nanostructured hybrid materials made of inorganic porous support functionalized with specific complexing agents of the element to extract that lead to the elaboration of high-performance materials.
  • This approach can also be applied to the development of new generation fuels or nitride, carbide or even mixed actinide oxide – carbide type transmutation targets. The use of composite materials and / or hybrids combining, in nanoscale, lanthanides and ultimately, actinides (molecular form or oxide) and an "organic" matrix based on carbon or carbon nitrides can lead to the synthesis of meso-structured carbides or nitrides. In this context, one of the goals of this team is to understand the irradiation defects behavior in nanostructured materials.

 

Mesostructured materials under irradiation

Mesoporous materials have some attractive characteristics for nuclear topics as fuel materials with controlled porosity, or for separation / decontamination, and even for waste conditioning purposes. In this perspective, it is necessary to know more about their behavior under irradiation. Their attractiveness toward this issue can be resumed by the combination two remarkable properties: the organization at the nanoscale, and the curvature of the interfaces. Indeed, the volume of defects generated by the interaction between incident particles (ions, neutron) and the material is typically of the order of one nanometer to about ten nanometers. We can assume that in a material that is organized at the nanoscale, the defects caused by the interaction can be more easily annihilated in the holes that are the interfaces (grain boundary, pore-solid interface) compared to a material with micrometric grain size for which the diffusion distance to the interface is much greater. In addition the curvature of the interface is a favorable factor for the recombination of defects created by irradiation due to the excess energy produced.