Chemical Disposition of Plutonium in Hanford Site Tank Wastes

Abstract

This report examines the chemical disposition of plutonium (Pu) in Hanford Site tank wastes, by itself and in its observed and potential interactions with the neutron absorbers aluminum (Al), cadmium (Cd), chromium (Cr), iron (Fe), manganese (Mn), nickel (Ni), and sodium (Na). Consideration also is given to the interactions of plutonium with uranium (U). No consideration of the disposition of uranium itself as an element with fissile isotopes is considered except tangentially with respect to its interaction as an absorber for plutonium. into plutonium and absorber element behavior under alkaline and plant process conditions. Three external reviewers, Scott Barney, independent consultant, and David Hobbs and Tracy Rudisill of the Savannah River National Laboratory examined the near-complete document and provided insightful, germane, and complementary comments. We thank Reid Peterson (PNNL) for project oversight and Lisa Staudinger (PNNL) for her attention and care in formatting and technically editing this manuscript. Finally, we gratefully acknowledge the fundamental and applied research into the chemistry of plutonium and other transuranic elements in alkaline media conducted by scientists and technicians of the Institute of Physical Chemistry of the Russian Academy of Sciences. In particular we note the scientific leadership of Professors

Evaluations of Mechanisms for Pu Uptake and Retention within Spherical Resorcinol-Formaldehyde Resin Columns

“…As summarized by Delegard and Jones (2015) 2-, at low and high pH, respectively, and B, as boric acid and sodium borate salts at low and high pH, have relatively high molar solubilities.…”

Recognition and Extraction of Cesium Hydroxide and Carbonate by Using a Neutral Multitopic Ion‐Pair Receptor

“…[1] Much of this is highly basic (pH>13; [OH − ] = 0.02 – 8.1 M; [CO 3 2− ] = 0.005 – 1.4 M). [2] Finding ways to lower the pH of this waste by removing the basic anions (e.g., OH − and CO 3 2− ), rather than adding a Brønsted acid, could prove advantageous. The same might be true in a variety of chemical process settings.…”

Characterization of wastes pertaining to naturally occurring radioactive materials (NORM) and the nuclear fuel cycle

“…There is approximately 8700 metric tons of aluminum present in the Hanford waste for a total of 3.2x10 8 moles. 46 The large quantity of Al 3+ in the tank waste is due to the prevalence in aluminum nitrate as a component of the separation processes and the inclusion of aluminum metal in early uranium fuel cladding materials (1956)(1957)(1958)(1959)(1960)(1961)(1962)(1963)(1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972). 46 Some of these tanks have a total concentration of 3 M aluminum, presumably mostly in the form of aluminate, as the pH resides around pH 12.…”

“…46 Some of these tanks have a total concentration of 3 M aluminum, presumably mostly in the form of aluminate, as the pH resides around pH 12. 46 The large quantities of organics and metals,…”

“…Metal oxides and hydroxides, in particularly Al and Fe, are present in numerous waste streams, including that of nuclear weapons production. Notably, the Hanford Site in Washington State, U.S., is the home of the first full-scale plutonium (Pu) production facility for nuclear-weapons purposes 4,46. To create the Pu metal needed for nuclear weapons, significant separation and purification processes were utilized that produced a large amount of nuclear waste.…”