1.3. The safety case2 is the collection of scientific, technical, administrative and managerial arguments and evidence in support of the safety of a disposal facility, covering the suitability of the site and the design, construction and operation of the facility, the assessment of radiation risks and assurance of the adequacy and quality of all of the safety related work associated with the disposal facility. Safety assessment, an integral part of the safety case, is driven by a systematic assessment of radiation hazards and is an important component of the safety case. The latter involves quantification of radiation dose and radiation risks that may arise from the disposal facility for comparison with dose and risk criteria, and provides an understanding of the behaviour of the disposal facility under normal conditions and disturbing events, considering the time frames over which the radioactive waste remains hazardous. The safety case and supporting safety assessment provide the basis for demonstration of safety and for licensing. They will evolve with the development of the disposal facility, and will assist and guide decisions on siting, design and operations. The safety case will also be the main basis on which dialogue with interested parties will be conducted and on which confidence in the safety of the disposal facility will be developed. @@2) The concept of developing a safety case for disposal facilities, as outlined in this publication, is used in many States. The terminology used is different, though, in some States. For example, in the United States of America the term ‘total system performance analysis’ is used (together with the regulations relevant to the specific disposal method), covering all aspects of the safety case as described in this Safety Guide. In France, the term ‘dossier’ is used to describe the safety case. In Germany and Switzerland, the term ‘Sicherheitsnachweis’ is used. In Spain, the term ‘estudio de seguridad’ is used to describe the safety case.