Neptunium Recovery in Reprocessing

This section describes processes for recovering neptunium from irradiated uranium. Neptunium is an example of one of the numerous elements in irradiated fuel that could be recovered as by-products of extraction of uranium and plutonium in the Purex process, 

In fast reactors, the reaction predominates. Typical concentrations of Np in 

Neptunium concentration in fuel from thermal reactors could be increased by recycling uranium containing U. 

Comparison of the potentials for the two neptunium couples with those for plutonium 

Because the distribution coefficient in TBP of hexavalent neptunium is higher than tetravalent, the hexavalent form is preferred for the first extraction from fission products. The first part of Table 10.22 gives equations for the concentration ratio of hexavalent to pentavalent neptunium calculated for the three oxidants listed there, with the coefficient evaluated from exp(-38.93 A °). 

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