Understanding the evolution of the repository and the olkiluoto site

Posiva Safety Case is organised in a portfolio including ten main reports: Site, Spent Fuel Characteristics and Inventories, Canister Design, Repository Design, Process, Evolution of the Repository and the Site, Biosphere Assessment, Radionuclide Transport, Complementary Evaluations of Safety, and Summary. This portfolio constitutes the basis of the Preliminary Safety Assessment Report, which will be presented to the authorities in 2012 as part of the repository construction license application. The Evolution report [1], which is the focus of this paper, is the main advance in the Safety Case portfolio since the implementation of the Safety Case plan [2] in 2005. The report provides the status of current knowledge with respect to the evolution of the site and the engineered barrier system and highlights areas where better understanding is needed. (authors)