Decommissioning and PIE of the MEGAPIE spallation target

A key experiment in the Accelerated Driven Systems roadmap, the MEGAwatt PIlot Experiment (MEGAPIE) (1 MW) was initiated in 1999 in order to design and build a liquid lead-bismuth spallation target, then to operate it into the Swiss spallation neutron facility SINQ at Paul Scherrer Institute (PSI) (Ref. 1). The target has been designed, manufactured in ATEA (France) then set-up, fitted with all the ancillary systems, on an Integral test stand in PSI for off-beam tests dedicated to thermohydraulic and operability tests, carried out during the last months of 2005. The system was then moved for the final implementation in the SINQ facility, with the ancillary systems, for irradiation, carried out from August 14th to December 21st, 2006. The irradiation allowed obtaining very important results particularly showing the very good operational behaviour of the target. Moreover a lot of results in the thermal hydraulic and neutronics fields, gas analysis contributed validating the design studies and the models used for that. The decommissioning of the target has been carried out and PSI teams have prepared the samples (760) for post irradiation examination (PIE). The samples have been distributed to the following partner laboratories (CEA, KIT, PSI, SCK·CEN and US-LANL). CNRS and ENEA will also contribute to the PIE, respectively in SCK-Mol and PSI hot Laboratories. The goal is to study the structural material properties changes due to the harsh environment of high temperatures, contact with flowing liquid metal (LBE) and proton irradiation. After presenting an overview of the project history, we describe the target decommissioning, PIE sample preparation and distribution and highlight first results that have been obtained.