The initial license application of a repository concept for disposal of radioactive waste is based on extensive site characterization, baseline monitoring, development of disposal designs and engineered barriers, test data on engineered barriers, and the integration of a series of models representing processes controlling the containment, release and migration of radionuclides from the repository to the accessible surface environment.
This information allows an initial assessment of safety-significant feature of the repository concept to be made. The multi-decade, pre-closure period of repository construction, operations, and waste emplacement, however, presents an extended, additional opportunity to seek and obtain further confirmation of the performance, effectiveness, and reliability of the repository concept. Such an extended program can be called “performance confirmation”, defined here as a program of activities to be conducted during the pre-closure construction and operational period to further test and augment the information, analyses and results of the initial construction license application (CLA). While there is no specific mention or requirement for ‘performance confirmation’ in Swedish regulations, SSMFS 2008:1 Chapter 2, Section 10 states requirements on a safety program that calls for a continuous systematic assessment of the facility’s safety and to safety improvement measures, which closely aligns with the motivation and goals of performance confirmation.