Hydrogen-isotope transport in Ti-added reduced activation ferritic/martensitic steel

The Korea Institute of Materials Science has been developing a new reduced activation ferritic/martensitic (RAFM) steel, named Ti-RAFM, in which Ti replaces Ta. It is characterized by higher mechanical strength than RAFM steel with Ta without loss of impact properties. The permeation and trapping of hydrogen, deuterium, and tritium in Ti-RAFM were investigated at temperatures of 160-600 degrees C. The properties of hydrogen and deuterium were determined using the continuous-flow method whereas that of tritium was calculated using a model associated with quantum harmonic approximation. This study reports the first complete datasets of the permeability of hydrogen, deuterium, and tritium in Ti-RAFM and the corresponding datasets for the diffusivity and solubility including the trapping energy and trap density, which were determined from the trapping phenomena observed at low temperatures of 160-300 degrees C. The ratios of hydrogen, deuterium, and tritium for the permeability, diffusivity, and solubility were also estimated. Furthermore, our results for Ti-RAFM were compared with the results for other RAFMs.