Final Report of Tank 241-C-105 Dissolution, the Phase 2 Study
Three clamshell grab samples were taken from Tank 241-C-105 in October 2015 in accordance with RPP-PLAN-60011. Analytical results of those samples were issued in the report RPP-RPT-59115 by Wastren Advantage, Inc., Hanford Laboratory. Solid phase characterization results were reported separately in LAB-RPT-15-00011 and in RPP-RPT-59147. The major solid phases reported to be present were dawsonite [NaAlCO 3 (OH) 2 ], trona [Na 3 (HCO 3 )(CO 3 )·2H 2 O], cejkaite [Na 4 (UO 2 )(CO 3 ) 3 ], and an unidentified organic solid, with minor amounts of gibbsite [Al(OH) 3 ], natrophosphate [Na 7 F(PO 4 ) 2 ·19H 2 O], and traces of unidentified iron-rich and manganese-rich phases. Note that the presence of dawsonite, trona, and cejkaite requires a relatively low pH, likely around pH 9 to 10. One aliquot of each grab sample was provided to 222-S Laboratory Process Chemistry for dissolution studies. Phase 1 of the dissolution testing followed the approved test plan, WRPS-1404813, Rev. 3, and examined the behavior of the Tank 241-C-105 solids treated with water, 19M sodium hydroxide, 2M nitric acid, and 0.5M oxalic acid/2M nitric acid. Phase 2 of the testing was conducted in accordance with instructions from the client and emphasized treatment with 19M sodium hydroxide followed by water washing. This is the report of the Phase 2 testing.