The development and status of performance assessment in radioactive waste disposal

The development of formal performance assessment in radioactive waste disposal has been in progress for around 10-15 years now. The time is particularly opportune for a review of the state-of-the-art because of current changes in the status of repository planning and implementation world-wide. Several major feasibility-type studies have been completed, the first full site-specific safety analyses are being performed for engineered underground disposal facilities for L/ILW, and - for HLW - the die are now being cast by implementers and regulators determining how the safety analyses for licensing are to be performed and assessed. This introductory paper reviews the development of performance assessment, including a reiteration of the aims and a recapitulation of the technical progress and achievements to date. The most important purpose, however, is to identify some key issues occupying safety analysts and regulatory reviewers involved in waste disposal today. The objective is to present the generally accepted consensus on the state of the art in performance assessment. 40 refs., 2 figs