Compaction of a Bed of Fragmentable ${\rm UO}_2$ Particles and Associated Acoustic Emission

The nuclear fuel of light water power reactors is manufactured by powder metallurgy. This method is also used for the production of fuels containing minor actinides which have high activity and long life. Given their radiotoxicity, maximum simplification in the manufacturing process is necessary in order to limit dissemination and retention of matter. In addition to this, the fuel must have a mostly open porosity. Implementation of particles of a few hundred micrometers and controlled cohesion could achieve this dual objective. However, the mechanical strength of compacts before sintering must be sufficient without adding binder. The phenomena which occur during the manufacturing of compacts are thus analyzed and quantified. We show that only a part of the particles breaks upon application of a stress of up to 600 MPa and it is possible to detect this fragmentation by acoustic emission (AE).