An Alternative Solvent Extraction Flowsheet for Separating ²³⁷Np from ²³⁸Pu for Space Power Applications

ABSTRACT

The production of ²³⁸Pu from ²³⁷Np, to the specifications required for space flight, requires the separation of plutonium from neptunium and a range of fission products. The valuable neptunium is then recycled into targets for further irradiation. At Oak Ridge National Laboratory (ORNL), a solvent extraction process has been developed to separate neptunium and plutonium that uses sodium nitrite to control the neptunium oxidation. This results in a neptunium product contaminated with sodium, which needs to be removed prior to recycling. We have developed a separation process that results in a sodium-free neptunium product with very low levels of plutonium contamination, there by reducing the number of purification steps and thus simplifying the process.

KEYWORDS:

• Neptunium
• plutonium solvent extraction
• hydroxylamine
• kinetics
• modelling

Supplemental data

Supplemental data for this article can be accessed on the publisher’s website.

Acknowledgments

The authors are grateful to NNL for internal research funding under the Advanced Recycle and Isotope Separations (ARIS) core science theme and to ORNL for helpful discussions.

Disclosure statement

No potential conflict of interest was reported by the authors.