Safety Evaluation of a Geological Repository

The Law of 30 December 1991 [1] confers to Andra the mission of assessing the feasibility of a repository of high-level and long-lived (HLLL) waste in a deep geological formation.

The present volume describes the result of all the studies which were conducted within Andra to assess this feasibility from the viewpoint of safety. As such, it complements the volumes entitled « architectures and management of the geological repository »and « phenomenological evolution of the geological repository » in that it uses the results obtained from studies given in these volumes in a safety-oriented perspective. Therefore, it reviews generally in an abridged fashion with respect to the developments contained in the two other volumes the main knowledge acquired from the engineering studies and the research work. It describes also part of the work not dealt with in the other volumes (particularly, the results obtained from the performance assessments).

Since safety is not an independent topic, but is closely related to the other work conducted on geological repository, it seems indispensable to recall the results already presented in other documents, explaining how the search for the best level of safety led to the retained options and to certain research rather than others. The two other volumes are based on a more subject oriented approach of their respective fields. Consequently, the two other volumes are not a prerequisite to read this volume. However, the reader interested in a more detailed view of the result of the studies or in more complete justifications about some points should refer to the other volumes or to documents which offer much more detail. In fact, it was not considered possible or advisable to try to account for all the work in the present volume because it would have compromised readability.

Chapter 1 of this volume presents the basic approach adopted to assess feasibility from a safety viewpoint within the context of a clay site based on the characteristics of the Meuse / Haute-Marne (MHM) laboratory site. It is an introduction to the rest of the analysis, which is intended to establish the framework for safety assessments, present the adopted approach and globally serve as a reader’s guide for the remainder of the present volume.