From MYRRHA to XT-ADS: lessons learned and towards implementation

The EUROTRANS project is an integrated project in the 6th European Framework Program in the context of Partitioning and Transmutation. It aims to deliver an advanced design of a small-scale Accelerator Driven System (ADS), XT-ADS, as well as the conceptual design of a European Facility for Industrial Transmutation, EFIT. The comparison between those two machines is described in another contribution. Since 1998, SCK•CEN has been designing a multipurpose ADS for R&D applications – MYRRHA - , which consists of a proton accelerator delivering its beam to a windowless liquid Pb-Bi spallation target that in turn couples to a Pb-Bi cooled, sub-critical fast core. The EUROTRANS partners have accepted the SCK•CEN offer to use MYRRHA as a starting basis for the XT-ADS design. Instead of starting from a blank page, this allowed optimizing an existing design towards the XT-ADS needs within the limits of safety requirements. In this paper we discuss the evolution from MYRRHA to XT-ADS, the lessons we have learned in this process and the perspectives for the future developments starting from the present XT-ADS design.