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| Main Authors: | , , , |
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| Format: | Recurso digital |
| Language: | |
| Published: |
Zenodo
2020
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| Subjects: | |
| Online Access: | https://doi.org/10.5281/zenodo.18694435 |
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Table of Contents:
- The Geosphere of the Accra Plains, made up of the very low permeable Togo and Dahomeyan rocks is a potential site to host a disposal facility for disused radioactive sources generated in Ghana. The geosphere constitutes a natural barrier for the possible leakage of radionuclides from the proposed disposal facility. This study assessed the migration of radioactive contaminant through the geosphere to the biosphere, from a hypothetical radioactive waste disposal facility sited in the Accra Plains. Lithologies of thirty-one (31) boreholes in the Plains were compiled and compared to determine a representative lithology of the Plains to develop the conceptual geological model. The geosphere between the near field of the disposal facility and an abstraction borehole situated down the hydraulic gradient from the disposal facility was discretised into sixty (60) compartments consisting of a rock matrix with a single planar fracture in water saturated porous rock. Transport in the fracture is assumed to obey an advection-diffusion equation, while molecular diffusion is considered the dominant mechanism of transport in porous matrix. The processes that have the potential to move contaminants around the system were represented as transfers between those compartments. This was implemented in the AMBER software. Radiation exposure of humans is an estimated effective dose to an adult from ingestion of well water from an abstraction borehole. The study considered abstraction boreholes located 100m, 500m, 2km and 5km from the disposal facility. The predicted results for liquid releases in terms of the calculated peak total dose in all cases were significantly lower than the dose constraint of 0.3mSv/y. The results thus indicate that the Accra Plains is capable of hosting a disposal facility for Ghana's disused radioactive sources.