Heel Removal Analysis for Mixing Pumps of Tank 8

Abstract

Computational fluid dynamics methods were used to recommend a slurry pump operational strategy for sludge heel removal in Tank 8. Flow patterns calculated by the model were used to evaluate the performance of various combinations of operating pumps and their orientation. The models focused on removal of the sludge heel located at the east side of Tank 8 using the four existing slurry pumps. The models and calculations were based on prototypic tank geometry and expected normal operating conditions as defined by Waste Removal Closure (WRC) Engineering. The calculated results demonstrated that for pump speeds higher than 1800 rpm and at a 130 inch liquid level, a recommended orientation of the slurry pumps could be provided, based on a minimum sludge suspension velocity of 2.27 ft per sec. Further results showed that the time to reach a steady-state flow pattern was affected by both the tank level and the pump speed. Sensitivity studies showed that for a given pump speed, a higher tank level and a lower pump nozzle elevation would result in better performance in suspending and removing the sludge. The results also showed that the presence of flow obstructions were advantageous for certain pump orientations.