Doping UO2 with aliovalent transition metals to increase grain size during sintering. The dopants segregates to grain boundaries (GBs) which cause local restructuring of GBs due to defects compensating mechanisms for charge balancing.

3D reconstructed microstructure (top row) and segmented porosity (bottom row) from X-ray tomography of U-10Zr fuel samples extracted at increasing radial distances: Center, Middle, Edge, and Fuel–Cladding interface. Each cube represents a 50 μm field of view. Segmented pore volumes (in blue) reveal changes in pore morphology and connectivity from the fuel center to the outer cladding interface, where larger, more interconnected porosity is observed near the edge and cladding.

Evolution of a Ni microcrystal’s Bragg peak during PWR coolant simulation. (A) Bragg peak cross sections are shown perpendicular to each axis. (B) First row: 3D phase isosurface evolution as visualized in ParaView. Second and third rows: Phase evolution at midsection slices in the ZX and YX planes, respectively. Dislocations are marked C–E with arrows indicating the direction of the phase spiral. An isometric view of the phase isosurface at 32.5 h is shown to the right of the phase plot, as rendered in ParaView.

Nickel microcrystal on SiO2/Si(001) support. Strain relaxation from X-ray beam exposure in reciprocal (top) and real (middle) space. The strain field energy (bottom) presents a quantitative decrease of the strain field inside the crystal.

Time evolution of a NiCo microcrystal in PWR coolant chemistry. A screw dislocation is observed starting at 6 hours of exposure.

Jossou Research Group Research Overview

The Jossou Research Group at MIT studies advanced materials for next-generation nuclear reactors. Because nuclear energy plays a growing role in decarbonizing the world's economy, engineers need reactors that can run at much higher temperatures and radiation doses than today's light water reactors.

Meeting these demands requires new structural materials and accident-tolerant fuels that perform reliably over a reactor's full lifetime. To address this challenge, our team improves existing materials and engineers new ones. We combine experiments, atomistic simulations, and data science to build a detailed, atomic-to-mesoscale picture of how materials behave.

This approach lets the Jossou Research Group uncover the mechanisms driving material performance under both normal and off-normal reactor conditions. For example, we study fuel and cladding materials proposed for the advanced reactor designs tracked by the U.S. Department of Energy's Office of Nuclear Energy. To see specific ongoing projects, visit our Research page, meet the team behind this work on our Team page, or browse recent findings in our Publications.

As a result, the Jossou Research Group continues to expand its work at the intersection of materials science, nuclear engineering, and computational modeling. To learn more about our capabilities, visit our Facilities page.

Diagram of the Jossou Research Group's overall research approach for nuclear materials science
Skip to content