Thermal Modeling Analysis of CST Media in the Small Column Ion Exchange Project

Three-Dimensional Thermal Modeling Analysis of CST Media for the Small Ion Exchange Project

“…The governing equations defined by the computational grid were solved by an iterative solution method. The detailed solution methodology was described in the previous work [2,3].…”

“…-22 - The waste tank was considered full (330 inches) of stagnant 6 M Na + supernate with the mixing pumps turned off so that the primary cooling mechanism was natural convection due to buoyancy effects in the tank fluid with the tank cooling system serving as the primary heat transfer pathway. (Note: Previous analysis considered other tank supernate volumes [2]. )…”

“…As specified in the associated Technical Task Plan [1], one objective of the present work was to compute temperature distributions within the ion exchange column module under accident scenarios including loss of salt solution flow through the bed and loss of coolant system flow. The column modeling domain and the scope of the calculations in this case were broadened relative to previous two-dimensional calculations [2] to include vertical temperature distributions within the packed bed of ion exchange media as well as the upper column plenum region containing only fluid. The baseline design conditions and in-column modeling domain for the ion-exchange column module are shown in Figure 1.…”

“…This shape is believed to be most representative of the actual mound shape formed in the tank, given that submersible mixing pumps will be available for media dispersion. Alternative configurations involving other geometrical shapes for the CST mound were evaluated in the previous work [2]. Sensitivity analysis for the in-tank region was performed for different amounts of CST media.…”

“…The calculations were conducted to ensure conservative predictions for the maximum temperatures achievable using the current baseline design. The degree of conservatism was reduced for in-column calculations relative to the previous work [2,3] by using a three-dimensional modeling approach and selecting parameters which were nearer to expected conditions. The degree of conservatism for the in-tank calculations was also reduced by lowering the soil penetration depth below the tank from 150 to 20 feet.…”