Reversibility of decisions is an important consideration in the step-wise decision-making process that is foreseen for engineered geologic disposal of radioactive waste. The implications of favouring retrievability of the waste within disposal strategies and the methods to implement it are also being considered by NEA Member countries.

This report reviews the concepts of reversibility and retrievability as they may apply to the planning and development of engineered geologic repositories. The concepts span technical, policy and ethical issues, and it is important that a broad understanding is developed of their value and implications. Furthermore, improved comprehension and communication of these issues will clarify the value of flexible, step-wise decision making in repository development programmes and may help to generate a climate conducive to the further progress of such programmes.