Modeling CST Ion Exchange for Cesium Removal From Scix Batches 1 - 4

Abstract

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Triplicate Sodium Iodide Gamma Ray Monitors for the Small Column Ion Exchange Program

“…Equilibrium will be maintained between the two radionuclides until this point, giving the excess 137m Ba less time to decay before arriving at the gamma monitors. Figure 4.3 shows the cesium column loading profile as predicted by ZAM modeling at the end of a typical SCIX batch 3 . In this scenario, the lead column is completely loaded with 137 Cs and the lag column is 30% loaded.…”

“…During production, the columns will each contain 440 gallons of CST resin with a 137 Cs loading capacity of up to 2300 Ci/gal, thus a fully loaded IXC can contain a total of 1.0 × 10 6 Ci of activity 1 . The DSS effluent from SCIX can have an average 137 Cs content of no more than 6 nCi/g (0.028 mCi/gal) 3 . The conversion between nCi/g and mCi/gal is based on a DSS density of 1.25 g/mL.…”

“…Before the DSS stream reaches an average 137 Cs concentration of 6 nCi/g, the spent CST will be sluiced out from the lead column to the Spent Resin Disposal (SRD) unit, ground, and sent to Tank 40, the DWPF feed tank. The column will then be refilled with fresh CST and the role of lead and lag column will be switched 3 . A diagram outlining the SCIX process may be found in Figure 1.1.…”

Three-Dimensional Thermal Modeling Analysis of CST Media for the Small Ion Exchange Project

“…Although the present analysis used 43.2 % void fraction as the nominal value, sensitivity analysis for 50% porosity was performed since the void volume fraction of the packed bed has a substantial impact on estimations of the thermal conductivity of a composite mixture. The previous work [8] used 50 % void fraction as an upper bounding estimate of the cesium loading inside the bed.…”

“… The bounding heat source term used of 600 Ci/L of packed bed is 123 % of the nominal cesium loading of 488.8 Ci/L predicted for the various SRS waste compositions recently considered for SCIX processing [8]. The heat source was calculated assuming secular equilibrium involving 137 Cs and 137m Ba decay.…”