Retained Gas Sampling Results for the Flammable Gas Program

Data Observations on Double Shell Tank (DST) Flammable Gas Watch List Tank Behavior

“…The VFI obtained several measurements in the crust on June 29, 1998, and September 11, 1998, that show void fractions exceeding 40% near the base. Several RGS segments were obtained from the crust layer in November and December 1998 that confirmed these values Mahoney et al 1999). …”

An Approach to Understanding Cohesive Slurry Settling, Mobilization, and Hydrogen Gas Retention in Pulsed Jet Mixed Vessels

“…Hydrogen is known to be only a portion of the gas that is generated within the waste, and for predictions using holdup correlations, we follow Stewart et al (2007) and assume that hydrogen is 25 vol% of the total generated gas. In a study of the retained gas composition in Hanford tank waste, Mahoney et al (1999) concluded that the gas retained in the convective layer of the waste was less than or equal to 25 mol%, which is equivalent to 25 vol%, hydrogen. Mahoney also noted that the gas in the nonconvective (sediment) layer had consistently higher hydrogen, so the value of 25% hydrogen is not a bounding value.…”

Material Balance Assessment for Double-Shell Tank Waste Pipeline Transfer

“…Extensive studies have been conducted to explain and quantify the gas content (e.g., Mahoney et al 1999). The effect of this gas content on the waste density (and therefore waste volume) during a transfer scenario can be determined by:…”

“…The supernatant liquid in AN-105 also contains gas at 2x10 -5 % (±1x10 -5 %) by volume (Mahoney et al 1999). It was assumed that this gas is all released, partially released, or completely retained after the transfer.…”