Monitoring Mixing – Pulse Jet Mixer (PJM) efficiency in the Hanford Double Shell Tanks
At the Hanford site (USA) the ability to effectively mix and transport consistent batches of nuclear High Level Waste (HLW) slurry from the Double Shell Tanks (DST) to the Waste Treatment Plant (WTP) presents a significant operational risk, with impacts on operation length and the quantity of treated product produced. The DSTs utilise rotating PJM assemblies which need to be monitored to ensure consistent feed.
A International nuclear services company secured a bid for a project based on monitoring PJM mixing at two different lab scales to better understand the behaviour of the PJMs in the Hanford DSTs. The two scaled tanks are 110 cm (43.2)” and 305 cm (120”) diameter clear acrylic test vessels, each equipped with two scaled PJM assemblies. The only way to accurately assess the action of the PJMs at different scales is to compare behaviour of the slurry live, in-line, and at both scales which, until recently, would be an extremely difficult task. To achieve this goal, the Nuclear Services company rely on the groundbreaking p2+ ERT platform supplied by ITS – the technology is volumetric (ie not point-based), and can be engineered into almost any vessel geometry.
ITS provides Electrical Resistance Tomography instrumentation that is robust, scalable, accurate, and volumetric, and can be used to accurately assess PJM behaviour (with respect to solids concentration, location, and homogeneity across the operational volume) in both two and three dimensions.