The purpose of this project is to model hydrogen embrittlement in high performance steels. To this end we will utilize an atomistically informed hierarchial multiscale modelling framework, for which we use phase-field modelling. This type of modelling relies on data from the atomic scale, which needs to be established within the present project. Thus we will also perform ad initio and classical atomistic modelling within the project to identify trap sites and migration energies. The computational efforts of the project are computationally intensive, which is why we apply for extensive computational resources.