EXAFS Study on Irradiated ODS Ferritic Steel

The commercial material PM2000 is investigated as a representative for the material class of Oxide Dispersion Strengthened (ODS) steels. ODS steels are envisaged as substance of structural components in Very High Temperature Reactors (VHTR). The VHTR concept is considered by the Generation IV International Forum, an initiative researching the next generation of nuclear power plants. The chosen ODS is mainly used for non-nuclear applications. In order to justify the applicability of this material within a neutron irradiative environment, the evolution of radiation damage must be investigated. PM2000 samples are therefore exposed to 4He2+ irradiation at different temperatures. The potential structural change is measured as a function of the radiation parameters, using Extended X-Ray Absorption Fine Structure (EXAFS) spectroscopy on the yttrium K-edge and on the iron K-edge. A degradation of the dispersoids or the steel matrix would show the limitation of this material candidate.