Size Determinations of Plutonium Colloids Using Autocorrelation Photon Spectroscopy

Actinide Environmental Chemistry

“…This value is close to that measured for Pu(OH) 4 [73,74], The solubility of the colloid appears to be between that of amorphous Pu(0H) 4 and Pu0 2 , however, the exact value depends on the degree of aging, i.e., crystallinity [75], Interestingly, the predominant solution species in equilibrium with the colloid under oxidizing conditions was found to be Pu(V) [76], Rai and Seme found that, if the Pu solution concentration at a given pH falls above the Pu(OH) 4 not form [77], The pH dependent solubility curves for the oxide, hydroxide and colloid are shown in Figure 17 [77], From these curves, it should be possible to estimate the concentration of Pu required for intrinsic colloid formation. The size of the Pu(IY) intrinsic colloids have been studied by ultracentrifugation [78] and autocorrelation photon spectroscopy [79,80]. They can vary in size from one to several hundred nanometers.…”

Formation of uranium(IV)-silica colloids at near-neutral pH

“…The tendency of tetravalent actinides to form colloids has been a topic in actinide research for more than a decade (Triay et al, 1991;Silva and Nitsche, 1995;Kersting et al, 1999;Silver, 2001). Repeatedly there have been hypotheses that actinide behavior in geochemical field experiments or site-specific simulation experiments are influenced by An(IV) colloids.…”

Technical Basis for Safe Operations with Pu-239 in NMS and S Facilities (F and H Areas)

“…He also found that, in the 1 g/L -15 g/L Pu solution range, polymerization begins at higher acidity and is more extensive at the higher Pu concentrations. Costanzo,et al,[8][9][10][11][12][13][14][15][16][17][18][19].1 g/L Pu at 25°C found similar trends. No polymer formed when the initial acidity was 0.1 M, but the degree of polymerization continuously increased as the acidity was lowered and was almost quantitative at 0.04 M. More recent systematic studies,20 most notably by Miles2 Lat higher Pu concentrations, confii these trends.…”