Study of candidate materials for new reactor systems using positron annihilation spectroscopy and Barkhausen noise

This paper is aimed on non-destructive analysis of candidate materials for the New Generation of Nuclear Reactors (GEN IV) and fusion technologies. It presents various construction materials as austenitic steel NF709, ferritic/martensitic (FM) steel EUROFER97 and two oxide dispersion strengthened (ODS) steels ODS EUROFER and MA956. Steels are studied in their base state and after simulated irradiation damage using a linear accelerator at the Laboratory of ion beams of the Slovak University of Technology. The kinetic energy of 2+He ions reached 500 keV, achieving irradiation induced damage roughly 10 dpa, which is relative to 0.1 C/cm2. Temperature during implantation of 2+He ions into the samples was about 52–60 °C. Applied non-destructive techniques are positron annihilation lifetime spectroscopy (PALS) and Barkhausen noise (BN). Both methods present results concerning different behavior of studied materials. FM steels strengthened by yttrium oxides after simulated irradiation damage, showed negligible change in intensities of positrons trapped in defects whereas in austenitic steel a significant hardening effect was observed. Barkhausen noise which was used as a supplementary method, proved initial hardness of ODS steels, therefore supporting the results acquired from PALS.