Examples of Kemakta’s hydrological, geochemical and reactive transport modelling projects are described below. They relate to the spent fuel repository at Forsmark (SR-site), the deep borehole alternative, and the low/intermediate waste repository for short lived radionuclides (SFR). A PDF version of each report can be accessed by clicking on the title.
Modelling of thermally driven groundwater flow in a facility for disposal of spent nuclear fuel in deep boreholes (2013). SKB P-13-10
Very deep boreholes are being considered as an alternative option for spent fuel disposal in Sweden. In this study, the thermal effects of deep borehole repositories on groundwater flow were modeled for the first time.
Model code: Connectflow.
SR-Site: Oxygen ingress in the rock at Forsmark during a glacial cycle (2010). SKB TR-10-57
The extent of oxygen ingress from the rock surface to repository depth through fractured granitic rock was evaluated for temperate, periglacial and glacial periods. The complex geochemical system involved in O2 consumption (redox reactions, mineral dissolution, regional scale hydrology, glaciation events) was simplified and evaluated using numerical models in PHREEQC, and transparent analytical solutions were developed for cautious (pessimistic) O2 ingress calculations. The model results were used to support the SR‑Site safety assessment
Model code: Matlab, ConnectFlow, PHREEQC
Potential alkaline conditions for deposition holes of a repository in Forsmark as a consequence of OPC grouting. R-12-17
Ordinary Portland Cement (OPC) has been suggested as a grout to hydraulically seal granitic rock fractures adjacent to ramp and shafts at the spent nuclear fuel repository at Forsmark. The propagation of an alkaline plume (alkali disturbed zone, ADZ) downstream from these fractures was therefore evaluated. This involved an extensive study of natural analogue studies as well as complex numerical Phreeqc models. Simplifications were also evaluated to justify their use in transparent analytical calculations.
Model codes: Crunchflow, ConnectFlow, Darcy Tools, Phreeqc, Phast, Matlab