Characterization of fresh EMPIrE and SEMPER FIDELIS U(Mo)/Al fuel plates made with PVD-coated U(Mo) particles

The HERACLES group and the US-DOE work jointly to develop dispersed U(Mo)/Al as LEU fuel for conversion of high performance nuclear research reactors. Within this frame, two irradiation programs are in progress. In the first, EMPIrE, mini-plates are tested in the ATR reactor (USA) and in the second, SEMPER FIDELIS, full-size plates are irradiated in BR2 (Belgium). In both experiments, U(Mo)/Al plates with optimized microstructure are tested under high duty conditions. This paper focuses on analyses made at CEA Cadarache on seven fresh plates made of atomized particles, with or without Mo homogenization, and with ZrN coating. Five EMPIrE mini-plates and two SEMPER FIDELIS full-size plates were examined by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). A particular attention is paid to the integrity of the ZrN coating (thickness, cracks…) and to the U(Mo) particles microstructure.