Swelling behavior of high density U₃Si₂ dispersion fuel

Within the framework of the LEU-FOREvER and EU-QUALIFY projects (H2020 Euratom work program), an irradiation test called High Performance research Reactors Optimized Silicide Irradiation Test (HiPROSIT) has been performed to demonstrate the acceptable in pile behavior of the high density U₃Si₂ fuel system. The HiPROSIT test consists of four (4) fuel plates which were irradiated at the BR2 reactor in Mol, Belgium in representative reactor conditions as a first step towards qualification of the fuel for use in high power research reactors (HPRR), primarily aimed at LEU conversions. Each of the fuel plates was designed to have U₃Si₂ fuel with various loadings at 4.8, 5.3, and 5.6 gU/cm³ and fuel meat thicknesses. After successful irradiation, all plates have achieved a local maximum burnup of ∼80 % U²³⁵ or ∼4.3E+21 fission/cm³. A stable and predictable behavior of the fuel is evidenced in the nondestructive and microstructural examinations. Furthermore, it was found that the as-fabricated porosity accommodates the initial swelling of the fuel, which limits the swelling of the plate.