The Dissolution of Desicooler Residues in H-Canyon Dissolvers

Gray, J.H.

Savannah River Site (S.C.)

关键词: Aluminium;    Uranium;    12 Management Of Radioactive Wastes, And Non-Radioactive Wastes From Nuclear Facilities;    Feasibility Studies;    Radioactive Waste Processing;   

DOI  :  10.2172/812070
RP-ID  :  WSRC-TR-2003-00171
RP-ID  :  AC09-96SR18500
RP-ID  :  812070

美国|英语

来源: UNT Digital Library

【 摘 要 】

A series of dissolution and characterization studies has been performed to determine if FB-Line residues stored in desicooler containers will dissolve using a modified H-Canyon processing flowsheet. Samples of desicooler materials were used to evaluate dissolving characteristics in the low-molar nitric acid solutions used in H-Canyon dissolvers. The selection for the H-Canyon dissolution of desicooler residues was based on their high-enriched uranium content and trace levels of plutonium. Test results showed that almost all of the enriched uranium will dissolve from the desicooler materials after extended boiling in one molar nitric acid solutions. The residue that contained uranium after completion of the extended boiling cycle consisted of brown solids that had agglomerated into large pieces and were floating on top of the dissolver solution. Addition of tenth molar fluoride to a three molar nitric acid solution containing boron did not dissolve remaining uranium from the brown solids. Only after boiling in an eight molar nitric acid-tenth molar fluoride solution without boron did remaining uranium and aluminum dissolve from the brown solids. The amount of uranium associated with brown solids would be approximately 1.4 percent of the total uranium content of the desicooler materials. The brown solids that remain in the First Uranium Cycle feed will accumulate at the organic/aqueous interface during solvent extraction operations. Most of the undissolved white residue that remained after extended boiling was aluminum oxide containing additional trace quantities of impurities. However, the presence of mercury used in H-Canyon dissolvers should complete the dissolution of these aluminum compounds.