Postclosure Safety Assessment: Data

Ontario Power Generation (OPG) is proposing to build a Deep Geologic Repository (DGR) for Low and Intermediate Level Waste (L&ILW) near the existing Western Waste Management Facility at the Bruce nuclear site in the Municipality of Kincardine, Ontario. The Nuclear Waste Management Organization, on behalf of OPG, is preparing the Environmental Impact Statement (EIS) and Preliminary Safety Report (PSR) for the proposed repository. The postclosure safety assessment (SA) evaluates the long-term safety of the proposed facility and provides supporting information for the EIS and PSR. The present report provides a collation of reference information for the assessment of the Normal Evolution Scenario in a clear and well-documented manner. The report includes waste, repository, geosphere, biosphere and exposure data. The data presented in this report are the reference data for the Normal Evolution Scenario. Data specific to Disruptive Scenarios are presented in the reports where those scenarios are assessed. The assessment has adopted scientifically informed, physically realistic point values for data that can be justified on the basis of the results of research and investigation. Where there are high levels of uncertainty and/or variability associated with data, conservative but physically plausible assumptions have been adopted to allow the impacts of uncertainties/variability to be bounded. Uncertainties and variability in data for some parameters are accounted for through the use of probability distribution functions (PDFs). The biosphere model adopts a deterministic approach, based on 95th percentile characteristics of the critical group consistent with the guidance from the Canadian Standards Association. While a wide range of data sources has been used to populate the report, key data compilations have been used for each component of the DGR system, including: -Waste data from the Inventory report for L&ILW; -Repository data from the preliminary design given in the PSR; -Geosphere data from the Geosynthesis and Descriptive Site Model reports; and -Biosphere and exposure data from the latest relevant Bruce nuclear site environmental assessment and derived release limit reports