Disposal of long-lived radioactive waste in engineered facilities, or repositories, located deep underground in suitable geological formations, is being investigated world wide in order to protect humans and the environment both now and in the future. In the specific field of safety, the modern concept of the safety case for deep disposal was developed in the 1990s and first presented in the NEA report Confidence in the Long-term Safety of Deep Geological Repositories: Its Development and Communication.
Recently, there has been notable convergence in documents published nationally and internationally on the understanding and development of long-term safety cases for deep disposal. The NEA brochure Post-closure Safety Case for Geological Repositories (2004) defines and discusses the purpose and general contents of such studies. Similar concepts are presented in the IAEA Safety Standards Series No.WS-R-4, co-sponsored by NEA. Following these developments, and more than 15 years after the OECD international symposium of 1989, it was appropriate to take stock of progress to date in member country programmes.
The symposium provided a point of reference for those involved in the development, presentation, and review of long-term safety cases. It also proved valuable experience to any person with responsibility for, or interest in, decision making in radioactive waste management.
The aims of the symposium were: