Progress of the R&D programme to develop a metal foil pump for DEMO

•The paper describes the role and potential of a metal foil pump to improve the DEMO fuel cycle architecture.•The superpermeation process is characterized based on five individual steps, which yields the baseline for the coordination of the pump development.•Coupling of experiments and simulations for the characterization of the cold plasma of the metal foil pump is lined out.•The theoretical background and experimental methods towards the foil material choice and optimal operation are presented.•Several risks for using a metal foil pump in DEMO are addressed next to approaches to investigate and mitigate those.