Description
During the construction and operation phases, the repository tunnel system is ventilated and the host rock is exposed to air. This can result in a number of processes that may affect long-term safety, including: formation of an unsaturated zone around the tunnels; potential oxidation of sulphides (pyrite) and organic carbon in the adjacent rock; microbial activity under aerobic conditions; evaporation of porewater and consequent accumulation of solutes (salt); carbonation of cement (access and ILW tunnels) by atmospheric carbon dioxide; and trapping of oxygen after backfilling potentially leading to aerobic corrosion of metals.
OPA Category
Category as used in the OPA assessment
OPA Number
Number as used in the OPA assessment
Waste Relevance
Classes of waste to which this FEP is relevant
NEA V1 IFEP Reference(s)
Related IFEPs from the NEA V1 IFEP list from 1999