Strategy for backfilling and sealing deep geological storage facilities for high-level waste in granite

The basic idea of final geological storage is that radioactive waste should be permanently isolated from the environment in very deep geological formations, confined with a series of different barriers acting individually or in combination. Multiple barriers provide a high degree of redundancy preventing radionuclides reaching the biosphere even if one is degraded or fails. Two types of barriers are used: natural (host rock and surrounding geological formations) and engineered (waste, container and backfilling and sealing materials). This paper presents the fill and seal strategy used for storage in granite following general safety principles and technical criteria and requirements for these structures that act as engineered barriers. (Author)