RSC-Programme - Interim Report. Approach and Basis for - Posiva

5The aim of the RSC is to develop a classification scheme to be applied for the repositorydesign and construction. This scheme includes definition of rock volumes suitable forthe repository panels, assessment of whether deposition tunnels or tunnel sections aresuitable for locating deposition holes and acceptance of a deposition hole for disposalbased on the rock properties. The developed criteria should be based on observable andmeasurable properties of the host rock. Together with interpretation, modelling andgeneral understanding of site properties, the criteria can then be used to show thatrequirements set on the rock can be fulfilled. By applying the classification scheme, theaim is to avoid features of the rock that may be detrimental for safety of the repository.The focus of these investigations has been on the reference concept KBS-3V withvertical deposition holes. Related work was also done for the alternative conceptKBS-3H with horizontal deposition drifts, although its emphasis has been on adeposition drift scale and the engineered barrier design.The RSC-programme is divided into three sub-projects which in turn include severaltasks:Definition of the performance targets on the host rock (TARGET)Development and testing of the criteria (DETECT)Definition of the engineering targets on the host rock (DESIGN)Sub-project TARGET is responsible for defining performance targets i.e. requirementson rock properties arising from the long-term safety. These are the basis for the practicalcriteria. It includes the tasks of reviewing proposed criteria against the performancetargets, and of evaluating how application of suggested criteria will contribute to thesafety case. Application of the rock suitability criteria will define the potential range ofinitial conditions for the host rock and forms thus basis also for the assessment of theconditions in the canister near field during repository and site evolution. Sub-projectDESIGN considers the engineering requirements and tracks how the criteria are appliedin layout design. Finally, the main work is carried out under sub-project DETECT. It isresponsible for defining the practical criteria based on observable and measurable siteproperties, testing the criteria, and applying the criteria for example in layout planning.The programme was started in 2007 and is planned to continue until 2012. During thePhase 1 of the project, from 2007 until the end of 2009, the focus has been on defininglong-term safety related and engineering requirements, as well as defining volumessuitable for locating panels of several deposition tunnels. However, as the long-termsafety mainly depends on the properties of the near field of the deposition hole and thelong-term safety related requirements mainly consider these properties, also preliminarycriteria for the deposition tunnel and deposition hole scale has been developed. Thefocus during 2010–2012 will be on further development of deposition hole scalecriteria, as well as on testing and demonstrating the use of the criteria in ONKALO.Posterior, specific features related to the KBS-3H alternative will be taken into account.Objectives and scope of the reportThe aim of this report is to summarise the work done so far during Phase 1 (2007-2008)of the RSC programme. Chapter 2 presents background for the RSC-development; theregulatory requirements, the HRC-classification and its testing with ONKALO data, aswell as related work done by SKB and within the KBS-3H project. The general