Climate forcing impacts upon uncertainties in boundary conditions of a repository for spent nuclear fuel caused by a re-glaciation of the Canadian shield

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In the Province of Ontario fully 50% of electrical power is provided by nuclear reactors which provide power that is free of accompanying greenhouse gas emissions. An unfortunate byproduct of nuclear power generation is that it leads to the production of waste in the form of long lived radio nucleides which, if they were to be released into the environment, could cause substantial harm to all components of the biosphere. It is therefore imperative that this waste be stored in a way that insolates it from biospheric escape. Radioactive waste disposal is a problem that is currently being addressed by all countries internationally which depend upon nuclear energy to power some fraction of their requirements. The solution of choice involves the development of a Deep Geological Repository (DGR) consisting of a vault constructed many hundreds of meters below Earth's surface in which the waste is stored in canisters designed to prevent escape. The development of such a repository for Canada must face the question as to how vulnerable such a repository might be to an episode of re-glaciation. Since the entire country has been glaciated and deglaciated approximately 9 times during the past 900,000 years, and since the half lives of many of the radio-nucleides of which the waste is composed may exceed 100,000 years, the issue of repository vulnerability in the event of such a re-glaciation event is potentially serious. The goal of this proposal is to provide an analysis of the uncertainties associated with previous analyses of the boundary conditions to which such a repository would be subject if a further such episode of glaciation were to occur. The most significant contributor to this uncertainty is expected to be that associated with the nature of the climate forcing that is responsible for the re-glaciation episode and it is upon this issue that this proposal is focused. To this end very recent advances in the modeling of the last such glaciation event are employed in which the associated surface boundary conditions are fully coupled to a modern coupled atmosphere-ocean climate model in order to assess the validity of the forcing conditions previously employed to infer the ice thickness variations in previous glaciation boundary condition analyses.