Practicality of a plasma mass filter for nuclear fuel reprocessing: Separating lanthanides from actinides

There is a growing recognition [1,2] of the need for used nuclear fuel recycling technologies that are more proliferation-resistant alternatives to the Plutonium/Uranium refining by extraction (PUREX). However, the implementation of a closed fuel cycle, and more precisely of the minor actinides transmutation step, requires removing a priori the lanthanides. The chemical separation options remain limited because of the chemical similarity of americium with the lanthanides fission products. Separating lanthanides from actinides has therefore been labeled as one of the most difficult challenge in separation science [3]. Plasma filters offer an advantage over chemical solutions in that elements are dissociated. Each element can consequently be filtered without regard to chemical form. Thus, plasma mass filters have been recently proposed with the objective of nuclear waste remediation [4,5]. In particular, the capability of a new mass called the magnetic centrifugal mass filter has been studied in this context [6], highlighting the potential of plasma mass filters for nuclear waste remediation. Here we analyze how such plasma filters could be helpful in separating lanthanides from actinides. More specifically, the influence of the elements mass shift as compared to the ones considered for nuclear waste remediation is investigated, with special care given to the modifications induced on the achievable plasma parameters. Estimations of achievable separation factor are obtained by means of numerical modeling.