Regulatory reviews of safety assessments of deep geologic repositories

The safety of underground repositories for radioactive waste must be demonstrated to the satisfaction of the implementing organisations, the regulatory bodies, the wider scientific and technical community, political decision makers and the general public. In particular, convincing arguments are required that engender confidence in the safety of the proposed repositories, taking into account the uncertainties that inevitably exist in forecasting the behaviour of complex natural and engineered systems over long periods. During the development of repositories, integrated performance assessments (IPAs) are normally carried out at key stages by the implementing organisation and reviewed by the regulatory authorities. The NEA 'IPAG-2' study was carried out in order to examine the experience of peer reviews of IPAs, and especially reviews performed in support of regulatory assessments, from both the implementer and regulator points of view. Seventeen organisations, representing a wide spectrum of national programmes and stages in repository development (see table), participated. The results of the study were published this year under the title Regulatory Reviews of Assessments of Deep Geologic Repositories: Lessons Learnt. Summary observations and recommendations of the study are presented below. (authors)