Geofirma Engineering has been responsible for all the detailed flow and transport modelling required for the Postclosure Safety Assessment of the OPG Low & Intermediate Level Waste DGR proposed for the Bruce site.
The NWMO is proposing to construct an underground facility for the management of low- and intermediate-level radioactive waste approximately 680 metres below the ground surface within the Paleozoic sedimentary bedrock of the Michigan basin (Cobourg formation) at the Bruce Nuclear site in Kincardine, Ontario.
A coupled two-phase flow and geomechanical model was used to predict the development of excavation damage around the HG-A tunnel and then model the damaged zone permeability.
T2GGM consists of a gas generation model (GGM), which calculates rates of gas generation and water consumption within a deep geologic repository (DGR) due to corrosion and microbial degradation of the waste packages, integrated with the widely used two-phase flow code TOUGH2.
The baseline characterization program developed and carried out by Geofirma at the Bruce nuclear site is the gold standard of Baseline Groundwater Characterization programs and the results from this program are being used by NWMO as part of their application to begin construction of the Deep Geological Repository for low and intermediate level nuclear waste.
Part of the Eurotom Fate Of Repository GasEs (FORGE) project, the FORGE benchmark modelling examined the transport of gas in a hypothetical repository, with the objective of improving gas migration modelling to support performance assessments at the repository-scale . Nine different groups contributed to the benchmark modelling exercise with different codes and modelling approaches, including Geofirma representing NWMO.
Since 2010 Geofirma has completed a variety of desktop feasibility studies of potential sites for hosting Canada’s Deep Geologic Repository (DGR) for used nuclear fuel, as part of NWMO’s APM program. Tasks included but were not limited to, detailed review of all existing geoscientific information, GIS mapping of any constraints, and structural lineament interpretation.
This modelling project represents one of the first efforts to understand the potential impacts of future glaciations deep geological repositories for radioactive waste. The effects of glaciation were addressed using a three-dimensional (3-D) numerical model of a hypothetical repository in the Canadian Shield, and coupling flow to mechanical loading from a continental glacier.
Bentonite-sand sealing systems are an important component in many proposed deep geological repositories for radioactive waste. To improve our understanding of the hydro-mechanical behaviour of this material, Geofirma was retained by the Canadian Nuclear Safety Commission to develop a model to simulate the SEALEX experiments on sand-bentonite.