The third phase of the OECD/NEA TDB project: TDB III

In 2003 with a foreseen duration of four years. The main objective of this new phase is to extend the existing critically reviewed database for elements of relevance in radioactive waste management, paying attention to the needs of the various national programmes. Following the decision by the Project Management Board (integrated by representatives of 16 organisations with responsibilities in radioactive waste management in 12 OECD member countries) the elements contemplated in this new phase are Th, Sn and Fe, with a higher priority being allocated to inorganic species and compounds. In addition to the corresponding review teams for these elements, an additional expert team has been constituted to prepare guidelines for the evaluation of thermodynamic data for solid solutions. As was the case in TDB Phase II, the basic project review methodology remains unaltered in TDB III. The Figure illustrates the relationship between the various TDB bodies, with an International Organisation, the OECD NEA, acting as Project Coordinator and linking the independent scientific teams and the project governing bodies. This organizational paradigm has proven successful with the recent completion of the five Phase II Reviews (Update, Ni, Se, Zr and Organic Ligands). The review and expert team activities were started in 2004 (except for Fe, being started in 2005) following an initiation stage. This preliminary stage was designed in order to tailor the team compositions to the existing literature for each element. The first reviews stemming from TDB III are scheduled to appear in published form in 2007. The successful completion of these objectives will add three further reports to the current series of nine volumes (dealing with the chemical thermodynamics of U, Np, Pu, Am, Tc, Ni, Se, Zr and compounds and complexes of these elements with oxalate, citrate, EDTA and isa). (authors)