With hydrogen rapidly becoming an important vector for renewable energy storage and distribution, the susceptibility of materials for hydrogen related damage becomes increasingly important again. In this context, materials with low susceptibility to hydrogen damage move into focus. These are predominantly fcc materials such as austenitic stainless steels. These materials are much harder to investigate with respect to hydrogen damage, since they have a very low diffusion coefficient for H at room temperature. As a result, the common approach of triggering hydrogen damage with cathodic reactions in aqueous environments is limited here, as the hydrogen simply doesn't diffuse deep enough into the volume of macroscopic specimens at temperatures where water is liquid. In addition, corrosive influences of a liquid medium cannot be excluded. These can influence the results, as it may not be possible to differentiate between a potential corrosion attack and the damaging effect of the hydrogen. These influences can be excluded by using hydrogen gas charges. As a result, gaseous hydrogen charging is a much more suitable method. Here, hydrogen gas at defined pressure and temperature is used to generate a defined thermodynamic state, with a defined concentration profile in the bulk material. To match this to concentration after long-term use in high pressure gas systems, high pressures of 700 bar (vehicle system pressure) and beyond are required, combined with temperatures that ensure full penetration. This can lead to hydrogen embrittlement effects in materials that are currently considered to be hydrogen resistant. In this presentation, we will show results from a new high pressure and high temperature hydrogen autoclave system developed at the Friedrich-Alexander Universität Erlangen Nürnberg. This system allows hydrogen and deuterium pressures of up to 1000 bar (100 MPa) and 300°C. At these conditions, many austenitic steels show significant influence of hydrogen on their mechanical properties. To understand these changes, advanced characterisation methods such as atom probe tomography and secondary ion mass spectrometry can be used. However, these methods often struggle to seperate the hydrogen from the specimen from hydrogen artificially introduced from their vacuum systems. We therefore also integrated the possibility to use deuterium as a tracer, to be distinguished from the artifical hydrogen. This also allows us to study the influence of the different diffusion kinetics of protium and deuterium on the mechanical behaviour e.g. in the slow strain rate test. We will present results from several austenitic steels including mechanical testing, microstructural influences and thermal desorption systems, after high pressure and temperature hydrogen and deuterium charging.