[en] Chapter 6 discusses the repository design features and operating procedures that will be used to ensure compliance with regulatory limits for preclosure releases, performance objectives for waste retrieval, and performance objectives for postclosure or long-term waste isolation. Chapter 7 discusses the analyses that were conducted in developing the repository design and the impacts of various external factors on the design of repository elements and the repository as a whole. Chapter 8 discusses the engineering design information needs that were identified during conceptual design as necessary to advance the current conceptual design to License Application Design (LAD). The quality assurance (QA) program applicable to the Architect/Engineer (A/E) activities during the repository conceptual design effort is defined in Chapter 9. 146 refs., 44 figs., 21 tabs