Thermal analysis for ion-exchange column system

•The column using one central and four coolant tubes provides an efficient cooling.•With 5 gpm (19 lpm) column flow, the maximum temperature increase should be below 5 °C.•The column temperature exceeds 100 °C within 24 h for the air-filled column.•A hemispherical shape is the worst, leading to the highest tank floor temperature.•Large CST volumes in a flat layer do not result in significant floor heating.

Models have been developed to simulate the thermal characteristics of crystalline silicotitanate ion exchange media fully loaded with radioactive cesium either in a column configuration or distributed within a waste storage tank. This work was conducted to support the design and operation of a waste treatment process focused on treating dissolved, high-sodium salt waste solutions for the removal of specific radionuclides. Normal operating conditions and accident scenarios (including loss of solution flow, inadvertent drainage, and loss of active cooling) were evaluated for the ion exchange column using bounding conditions to establish the design safety basis. The modeling results demonstrate that the baseline design using one central and four outer cooling tubes provides a highly efficient cooling mechanism for reducing the maximum column temperature. In-tank modeling results revealed that an idealized hemispherical mound shape leads to the highest tank floor temperatures. In contrast, even large volumes of CST distributed in a flat layer with a cylindrical shape do not result in significant floor heating.