(128b) Erosion and Mobilisation of Highly ACTIVE Simulant Suspensions with Impinging Vertical Jets

Based on the nuclear industry in the U.K., storage of nuclear waste poses a particularly complex risk. Part of the waste during storage before being disposed of begins to form colloidal particles. These particles begin to settle out, and can compromise the integrity of their storage container. Using an Impinging vertical liquid jet is the means to prevent this. However the operational effectiveness of these jets is unknown due to the nature of the containers. Reduced scale modelling is required to assess their efficacy, and understand the dimensionless results as they allow systems of scale to be compared. This is of particular interest due to the wide reaching applications to all industries that may require utilisation of impinging jets, or require mass transfer, or even heat transfer.

An experimental rig of 0.5 m³ has been used to model the central jet of the storage tank system. A Honite simulant (SiO₂, glass spherical particles) of varying size distributions has been used for the initial non-cohesive particle testing, and modelling. Each experiment uses 10 different jet diameters. Data is collected with an Ultrasonic Velocity Profiler, which scans the simulant bed in real time under impingement utilising an automated traverse. Acoustic backscatter data was recorded to yield a dynamic scour depth, and dynamic crater radius to allow dimensionless analysis of the erosion for each size distribution. Dimensionless analysis takes the form of the Erosion Parameter, E_c, which allows comparison for systems of scale and a means of correlating multiple simulants against one another, so patterns are easily identifiable. Part of the dimensionless analysis was also to deduce the Shield’s Parameter from vane viscometry to allow for a comparison of erosion behaviours taking into account particle properties, flow properties and the overall influence these have on the erosion profile.