PNNL

Abstract

The goal of this study is to fit model parameters to changes in waste level in response to barometric pressure changes in underground storage tanks at the Hanford Site. This waste compressibility is a measure of the quantity of gas, typically hydrogen and other flammable gases that can pose a safety hazard, retained in the waste. A one-dimensional biconical-pore-network model for compressibility of a bubbly slurry is presented in a companion paper. Fitting these results to actual waste level changes in the tanks implies that bubbles are long in the slurry layer and the ratio of pore-body radius to pore-throat radius is close to one; unfortunately, capillary effects can not be quantified unambiguously from the data without additional information on pore geometry. Therefore determining the quantity of gas in the tanks requires more than just slurry volume data. Similar ambiguity also exists with two other simple models: a capillary-tube model with contact angle hysteresis and spherical-pore model.