Use of cyanex-301 for separation of Am/Cm from lanthanides in an advanced nuclear fuel cycle

As part of the Advanced Fuel Cycle Initiative (AFCI), technologies for advanced aqueous processing of spent LWR fuel are being developed. Included in this program is the separation of Am and Cm from the lanthanides. This separation would allow the Am/Cm to be fabricated into a target and recycled to a reactor and the lanthanides to be disposed of with the raffinates from the process. A Laboratory Directed Research and Development (LDRD) Project at the INEEL is investigating the use of the active extradant in the Cyanex-301 reagent, bis(2,4,4-trimethylpentyl)dithiophosphinic acid, as a potential method to accomplish this separation. Specifically, the extractant is being developed based on an ammonium acetate/acetic acid buffered feed to the process which can be used to strip the actinides and lanthanides from a preceding transuranic separation process. The extraction and scrub distribution coefficients of Am and Eu with this extractant, as a function of total acetate concentration and pH, have been measured. Additionally, the extraction behavior of several additional lanthanides are compared. The potential for developing a Cyanex-301 process for the separation of Am/Cm from lanthanides to support an advanced nuclear fuel cycle is discussed.