Consecutive to the work of the European Technical Working Group on ADS, the Preliminary Design Study of an Experimental ADS was launched in 2001 as a 5th Framework Program EC project. A special working package was dedicated to the accelerator design, and in particular taking into account that the issue of “beam trips” could be a potential “show-stopper” for ADS technology in general. A reference solution, based on a linear superconducting accelerator with its associated doubly achromatic beam line has been worked out up to some detail. For very high reliability, the proposed design is intrinsically fault tolerant, relying especially on highly modular “de-rated” components associated to a fast digital feedback system. A programme for the remaining R&D, focused on experimental reliability demonstration of prototypical components, has been elaborated. This R&D will be performed in the 6th Framework Program EC project EUROTRANS, which presently is just starting