Water Solubility of Plutonium and Uranium Compounds and Residues at TA-55

Reilly, Sean Douglas¹  Smith, Paul Herrick¹  Jarvinen, Gordon D.¹  Prochnow, David Adrian¹  Schulte, Louis D.¹  DeBurgomaster, Paul Christopher¹  Fife, Keith William¹  Rubin, Jim¹  Worl, Laura Ann¹ 

[1] Los Alamos National Lab. (LANL), Los Alamos, NM (United States

关键词: URANIUM OXIDES U3O8;    URANIUM DIOXIDE;    ASHES;    PLUTONIUM PHOSPHATES;    URANIUM CARBIDES;    URANIUM NITRATES;    MOLTEN SALTS;    PLUTONIUM CHLORIDES;    WATER;    SOLUT;   

DOI  :  10.2172/1257103
RP-ID  :  LA-UR--16-24113
PID  :  OSTI ID: 1257103
Others  :  TRN: US1601490

美国|英语

来源: SciTech Connect

【 摘 要 】

Understanding the water solubility of plutonium and uranium compounds and residues at TA-55 is necessary to provide a technical basis for appropriate criticality safety, safety basis and accountability controls. Individual compound solubility was determined using published solubility data and solution thermodynamic modeling. Residue solubility was estimated using a combination of published technical reports and process knowledge of constituent compounds. The scope of materials considered includes all compounds and residues at TA-55 as of March 2016 that contain Pu-239 or U-235 where any single item in the facility has more than 500 g of nuclear material. This analysis indicates that the following materials are not appreciably soluble in water: plutonium dioxide (IDC=C21), plutonium phosphate (IDC=C66), plutonium tetrafluoride (IDC=C80), plutonium filter residue (IDC=R26), plutonium hydroxide precipitate (IDC=R41), plutonium DOR salt (IDC=R42), plutonium incinerator ash (IDC=R47), uranium carbide (IDC=C13), uranium dioxide (IDC=C21), U₃O₈ (IDC=C88), and uranium filter residue (IDC=R26). This analysis also indicates that the following materials are soluble in water: plutonium chloride (IDC=C19) and uranium nitrate (IDC=C52). Equilibrium calculations suggest that PuOCl is water soluble under certain conditions, but some plutonium processing reports indicate that it is insoluble when present in electrorefining residues (R65). Plutonium molten salt extraction residues (IDC=R83) contain significant quantities of PuCl₃, and are expected to be soluble in water. The solubility of the following plutonium residues is indeterminate due to conflicting reports, insufficient process knowledge or process-dependent composition: calcium salt (IDC=R09), electrorefining salt (IDC=R65), salt (IDC=R71), silica (IDC=R73) and sweepings/screenings (IDC=R78). Solution thermodynamic modeling also indicates that fire suppression water buffered with a commercially-available phosphate buffer would significantly reduce the solubility of PuCl₃ by the precipitation of PuPO₄.