Gamma radiolytic stability of CyMe4BTBP and the effect of nitric acid

Within international research in partitioning and transmutation (P&T), the separation of trivalent actinides (An(III)) from the chemical similar trivalent lanthanides (Ln(III)) is a main task that was comprehensively studied within the last two decades [1–3]. The investigated solvent extraction processes often follow the plutonium uranium reduction extraction (PUREX) process, in which uranium and plutonium are recycled from dissolved spent nuclear fuel solutions. For An(III) separation, a two-cycle concept, the so-called DIAMEX-SANEX concept, was developed [4]. In the fi rst cycle the trivalent actinides were co-separated together with the lanthanides in the diamide extraction (DIAMEX) process [5, 6]. In the subsequent selective actinide extraction (SANEX) process, An(III) were selectively partitioned using the highly selective nitrogen donor ligand CyMe4BTBP (6,6-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo[1,2,4]-triazin-3-yl)-[2,2]-bipyridine) (Fig. 1) [7, 8]. A hot SANEX process demonstration was conducted using a genuine feed solution containing Ln(III) as well as Am(III) and Cm(III). Those An(III) were selectively extracted, whereas the lanthanides were routed to the raffi nate stream [9]. In further work this SANEX process was modifi ed to be able to extract the actinides directly from PUREX raffi nate [10–12]. Gamma radiolytic stability of CyMe4BTBP and the effect of nitric acid Holger Schmidt, Andreas Wilden, Giuseppe Modolo, Jaroslav Švehla, Bohumir Grüner, Christian Ekberg