Plutonium solubility additives effect

The effect of fluoride was further demonstrated by the increase in plutonium solubility in deionized water from about 11 percent to essentially 100 percent by addition of sufficient NaF to raise the fluoride concentration to that of basalt ground water. It is likely that the enhanced solubility of plutonium in waters containing high fluoride concentrations is the result of stabilization of Pu(IV) in solution by formation of fluoride complexes. Normally Pu(IV) is the least soluble of the four... 

In the presence of high concentrations of both sulfate and fluoride, the speciation results are somewhat more difficult to interpret. Generally, the effect of fluoride predominates over that of sulfate, but not always. In deionized water containing added fluoride and sulfate to equal the concentrations of these two anions in basalt and shale ground waters, respectively, essentially all the plutonium was soluble—similar to its behavior in deionized water containing only added fluoride. Also, addition of sodium sulfate to basalt ground water to increase its concentration to that of shale ground water had no appreciable effect on plutonium solubility. 

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