Carbon-14 Project Phase 2 - Formation of a Gas Phase and its Migration.

Carbon-14 is a key radionuclide in the assessment of the safety of a geological disposal facility (GDF) for radioactive waste, because of the potential radiological impact of gaseous carbon-14 bearing species. RWM has established a project team, in which the partners work together to develop an holistic approach to carbon-14 management in a geological disposal system. This report is part one a suite of reports produced as part of the project. This report is concerned with work to understand the likely formation of a gas phase, and its subsequent migration through the near and far field. In the absence of (i) a site for geological disposal of radioactive wastes and (ii) detailed information on the GDF design, it is not possible to develop a single conceptual model for how carbon-14 bearing gases might migrate from a GDF to the biosphere. Rather, at this generic stage, it is appropriate to consider a range of behaviours. A set of illustrative, post-closure cases is defined, which can be used to link the generation rates of carbon-14 bearing gases to radiological risk