Simplified heat transfer model for highly active raffinate contained in buffer storage tanks

The research develops a simplified heat transfer model that allows prediction of the temperature response of the radioactive contents of a buffer storage tank at Sellafield, UK. The model emanates from an energy balance around a singular tank with comprehensive analysis of the heat transfer phenomena. A converged solution has been demonstrated by comparing different numerical solution techniques. The model has been validated using measurements made at Sellafield indicating strong agreement in trends. The results indicate, whilst storing a full tank of radioactive liquor, the vessel contents will not reach its boiling point of 95 °C but will instead reach an equilibrium temperature of 89 °C. The results also indicate that the model provides more accurate predictions compared with current operational assessments. Simulations from the model revealed the tanks can safely store material for approximately 67% longer than is predicted by current practice. The model has been developed in Microsoft Excel ® and can be run with minimal computational power on any machine. It includes a user-friendly interface allowing operators to generate results from a range of scenarios by running simulations within minutes, and provide operations personnel with more information to influence decisions surrounding industrial-scale problems.