Tank 41H Post-Dissolution Saltcake Core and Supernate SampleAnalysis

This report provides analyses of the samples from Tank 41H. The characterization also includes supernate samples pulled from the surface (347 inch) and 250 inch levels of the salt supernate. The three saltcake samples (HTF-E-03-145, 146, and 147) were filled to nearly their capacity with saltcake and free liquid, with an average saltcake bulk density of 2.06 g/cm3. The undrained saltcake from the bottom of the middle sample (HTF-E-03-146) had a water content of 4.1 percentage weight, a 137Cs activity of 0.14 Ci per gallon of saltcake, and an alpha content of 1.4E+4 pCi/g. The undrained saltcake from the bottom of the bottom sample (HTF-E-03-147) had a water content of 8.5 percentage weight, a 137Cs activity of 0.17 Ci per gallon of saltcake, and an alpha content of 3.0E+4 pCi/g. Interstitial liquid drained from the middle sample (HTF-E-03-146) had a density of 1.43 g/cm3, a soluble solids content of 45.4 percentage weight, a 137Cs activity of 0.78 Ci per gallon of interstitial liquid, a nd an alpha content of 1.1E+4 pCi/mL. An analysis of material from the top of the top sample (HTF-E-03-145) is provided in support of Nuclear Criticality Safety Evaluations. The as-received saltcake and the residual insoluble solids had a uranium-235 enrichment of approximately 12.2 per cent. Characterization focused on providing information on fissile radionuclides, potential neutron poisons, and other potential diluents. Supernate samples pulled from the surface and from the 250 in. levels of the C1 and C3 risers yielded information on the vertical and lateral tank supernate homogeneity. The 137Cs content of these Tank 41H samples averaged 0.56 Ci/gal for the C3 riser and 0.65 Ci/gal for the C1 riser. The 238Pu content of the four unfiltered samples ranged from 1.41E+4 pCi/mL to 2.21E+4 pCi/mL. Scanning electron microscopy of saltcake from sample HTF-E-03-146 revealed several features consistent with mineral dissolution: sub-rounded appearance of grains, lack of coatings by secondary precipitates, and crevices and indentations in some grains