Plutonium conversion chemistry

The complete chemistry of plutonium 1 iquid-to-solid conversion processes, especially peroxide and oxalate precipitation, should be further studied. Research and development of direct thermal denitration methods should also be pursued. 

The following pages will describe several examples of pyrochemical processing as applied to the recycle of plutonium, and will briefly review the fundamental chemistry of these processes. We shall review the conversion of plutonium oxide to plutonium metal by the direct oxide reduction process (DOR),the removal of americium from metallic plutonium by molten salt extraction (MSE), and the purification of metallic... 

Radiation chemistry also made it possible to prepare radicals and ions of interest and study their properties. With the advent of pulse radiolysis, it was possible to directly explore the reactivity of such intermediates. In fact, many reactions that were suggested to be of importance in solar energy conversion could be more cleanly studied using radiation chemistry. Similarly, questions about the mobility of actinide species in the biosphere often depended on the reactivity of different oxidation states of materials such as plutonium. Thus, it was possible to show that plutonium oxides were unlikely to move quickly through water in the earth, because the soluble oxides were very reactive and the equilibrirrm values were far to the side of the insoluble compounds. 

Complicating the development of ISEs for higher actinide ions is their inherent radioactivity. They also have chemistry tiiat often differs from that of the uranyl cation. Actinides from americium to lawrencium display solution-phase chemical features that resemble those of the trivalent lanthanides. Conversely, in certain oxidation states, the early actinides (thorium through neptunium) often mimic transition metals. Also, as mentioned above, many of the actinides can exist in a large number of oxidation states. For instance, in the case of plutonium, four oxidation states can exist simultaneously in aqueous solution. Finally, as true for the lanthanides, complex salts with hydroxide, halogens, perchlorates, sulfates, carbonates, and phosphates are well known for most of the actinides. 

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