The Collaborative EC Project ReCosy

The Collaborative Project (CP) ReCosy (Redox Controlling Systems) was established in 2008. It falls within the EURATOM program and is implemented within the European Commission’s 7^th Framework Program. Main objectives of CP ReCosy are the sound understanding of redox phenomena controlling the long-term release/retention of radionuclides in nuclear waste disposal and providing tools to apply the results to Performance Assessment/Safety Case. Although redox is not a new geochemical problem, different questions are still not resolved and thus raised by implementers and scientists. Radionuclide redox transformations on minerals are considered to be decisive scenarios in various FEP lists. 32 institutions from 13 European countries contribute to the 4-years CP by i) development of advanced analytical tools, ii) investigations of processes responsible for redox control (thermodynamically and kinetically controlled processes, surface reactions and microbial processes), iii) provision of required data on redox controlling processes, and iv) response of the disposal systems to external/internal disturbances. Systems which are investigated comprise simple very well defined ones under controlled laboratory conditions, complex laboratory systems, near-natural systems in the laboratory, real systems, and near-field systems controlled spent nuclear fuel. The scientific results of the CP ReCosy are reported during annual workshops (AW). The first AW took place in February 10–12, 2009. The scientific contributions underwent a peerreview and are published in the form of workshop proceedings together with scientific-technical overview papers of the different project workpackages. The present paper summarizes the main results obtained after the first year of ReCosy. The status during the project preparation phase of the CP ReCosy is published elsewhere [1].