Beyond U/Pu separation: Separation of americium from the highly active PUREX raffinate

This review provides a comprehensive overview of published hydrometallurgical chemical processes capable of separating americium from curium and the lanthanides. A search for highly selective and robust americium separation methods is motivated by the fact that americium isotopes contribute significantly to the long-term heat load and residual radiotoxicity of high level waste originating from the PUREX process, nowadays still the key reprocessing technology to recycle uranium and plutonium from spent nuclear fuel. The separation (partitioning) and subsequent nuclear transmutation (or burning) of americium would allow a substantial improvement in the construction of an underground final repository and provide safety benefits – highly relevant for the exploitation of such a facility over extended periods of time. Besides the discussion of basic properties of the various separation methods, an evaluation of their compatibility with upstream and downstream processes as well as the treatment of secondary waste streams is also provided.