A review of factors influencing underground construction quality and the performance of engineered features

This report describes research to identify and rank the factors that should be considered for an assessment of the radioactive containment capability of repository engineered features. Containment is to be achieved through the use of multiple barriers to radionuclide movement, including the waste, waste container, repository structures and backfill, and repository seals. A review of the literature is used to identify radionuclide mobilisation and transport processes for the anticipated environmental conditions, and to compile a data base of repository design features, functional requirements, and design objectives. For selected design components, the report identifies alternative designs and factors contributing to design, focusing on the requirements for a design process, design specifications, construction requirements, and quality assurance requirements for the both design and construction. Existing practice in large, underground civil construction projects is used as a part of comparison, in conjunction with reported performance assessments, to determine those areas in which the repository developer will need to provide additional data, justification, and documentation prior to construction to ensure that performance requirements can be achieved. (Author)