Scaling for integral simulation of mixing in large, stratified volumes Original Research Article

In this paper we develop scaling relationships for mixing in large stratified volumes, both for steam/nitrogen mixtures in containment compartments and for water in suppression pools. The results apply to scaling for integral tests of passive reactor containment systems. Buoyant jets from injected fluids and buoyant wall jets generated by hot and cold surfaces provide the primary mixing in these passive systems. The buoyant jets entrain and transport the stratified fluid, mixing the fluid and reducing the vertical temperature and concentration gradients. We show that scaling for mixing can be satisfied simultaneously with scaling for two-phase natural circulation. The scaling requires a reduced height, accelerated time facility. Accelerated time scaling is advantageous for studying long-term behavior of interest in passive systems, while reduced height improves long-term heat loss, decreases power requirements, and makes simulation of blow-down mixing feasible.