HR: 14:45h
AN: IA33A-04    [Abstracts]
TI: Ontario Power Generation's Proposed Deep Geologic Repository, Tiverton, Ontario, Canada
AU: * Jensen, M
EM: m.jensen@nwmo.ca
AF: Nuclear Waste Management Organization, 22 St. Clair Ave. East (6th Floor), Toronto, ON M4T 2S3, Canada
AB: Ontario Power Generation is proposing to develop a Deep Geologic Repository (DGR) for the long-term management of its Low and Intermediate Level Radioactive Waste (L&ILW) at the Bruce site located near Tiverton, Ontario, 225 km northwest of Toronto. The shaft accessed repository, as envisioned, would accommodate 200,000 m³ (as packaged) of L&ILW in emplacement rooms excavated at a depth of 680 m within the Ordovician age argillaceous limestone Cobourg Formation. The Bruce site is underlain by an approximate 860 m thick Paleozoic sedimentary sequence comprised of near horizontally bedded carbonates, shales, evaporates and sandstones, Devonian to Cambrian in age, overlying crystalline basement rocks. Regional and site-specific geoscientific studies to verify the suitability of the Bruce site to host the DGR were initiated in 2006. The focus for the geoscientific investigations has been on gathering data to develop and test an understanding of the evolution and stability of the geologic, hydrogeologic, hydrogeochemical and geomechanical environ as it relates to demonstrating repository safety. Scheduled for completion in 2010, the interim results, which have included the drilling, coring and testing of 4 deep boreholes, are providing evidence of a predictable geosphere with a deep seated (>400 m), low permeability (K < 10^-13 m sec^-1), low porosity (0.01-0.08), saline (TDS > 250 gm l^-1) groundwater regime that is ancient and resilient to external perturbations (e.g. glaciation). Work program activities in this regard have included, among others, detailed studies of rock core lithology, mineralogy and petrophysics, rock matrix pore fluid and groundwater characterisation, in-situ rock mass hydraulic testing, geomechanical rock core testing, 2-D seismic reflection surveys and long-term hydraulic borehole instrumentation. These data, in addition to regional and site-scale hydrogeologic modelling of the sedimentary sequence that among other aspects is examining groundwater system evolution through an understanding of long-term environmental tracer migration and observed abnormally elevated and depressed formation pore pressures, are to be integrated as part of a Geosynthesis document for the project supporting a case for safety. This presentation will provide an overview of the DGR program and the role of geoscience as it is contributing to an understanding of far-field barrier performance and long-term DGR safety.
DE: 1832 Groundwater transport
SC: International Association of Hydrogeologists, Canadian National Chapter [IA]
MN: 2009 Joint Assembly