Reasoned Argument Why Large-Scale Fracturing Will Not Be Induced by a Deep Geological Repository
Rock Engineering 2009 - Rock Engineering in Difficult Conditions
This paper outlines a reasoned argument that no large-scale fracturing or faulting will be induced in the host rock by a deep geological repository (DGR) for used nuclear fuel waste. Four DGR designs in three possible host rocks, including crystalline and sedimentary rock types, are considered. The reasoned argument draws from results of previously conducted thermal-mechanical analyses and simple scoping calculations using closed-form solutions, along with evidence from experiments conducted in Canada and elsewhere. It is concluded that large-scale fracturing in the far-field is implausible given the expected in situ stress conditions in relation to rock strength. Near-field damage development and fracturing are expected in many of the DGR scenarios in the different rock types, but these near-field effects are not expected to lead to large-scale fracturing that could compromise the integrity of the DGR and surrounding rock mass. Additional analysis and characterization activities are recommended to further validate the reasoned argument. Thermo-poro-elastic loading of the rock mass is identified as one possible driving mechanism that should be studied further.
Nuclear waste disposal, Deep Geological Repository, excavation damage, DGR, large-scale fracturing