PERFORMANCE ASSESSMENT OF THE GEOSPHERE BARRIER OF A DEEP GEOLOGICAL REPOSITORY FOR SPENT FUEL - THE USE OF INTERACTION MATRICES FOR IDENTIFICATION, STRUCTURING AND RANKING OF FEATURES, EVENTS AND PROCESSES

This paper summarises a study where the basic device in the Rock Engin eering Systems (RES) approach, the interaction. matrix, was used to id entify, structure and rank features, events, and processes (FEPs) desc ribing barrier performance and radionuclide behaviour in the far-held of a deep geological repository for spent fuel. The study has shown th at it is feasible to use an interaction matrix both for the structurin g of the process system (PS) and for visualisation of the PS. The deve loped documentation system increases the transparency of the system de scription and makes it possible to trace back the judgements made duri ng the construction of the matrix. This will facilitate review work an d future revisions as well as consistent treatment of different issues in the system. This study is a first step in the application of a sys tematic method based on interaction matrices to establish a structured PS. The next step would be to develop the PS for the remaining parts of the repository system to the;same level as has been done for the fa r-held system. (C) 1997 Elsevier Science S.A.