An Accelerator Driven System (ADS) for transmutation of nuclear waste typically requires a 600 MeV -1 GeV accelerator delivering a proton flux of a few mA for demonstrators, and a few tens of mA for large industrial systems. Such a machine belongs to the category of the high-power proton accelerators, with an additional requirement for exceptional reliability: because of the induced thermal stress to the subcritical core, the number of unwanted beam-trips should not exceed a few per year, a specification that is far above usual performance. This paper describes the reference solution adopted for such a machine, based on a so-called "fault-tolerant" linear superconducting accelerator, and presents the status of the associated R&D. This work is performed within the 6 th Framework Program EC programme EUROTRANS.