Reprocessing of spent nuclear fuel (SNF) has been, for a half-century, playing a central role in an enhanced utilization of nuclear energy. In the rst generation of reprocessing, about 7.5-8.0 × 105 t of low burn-up uranium was processed during the Cold War era to recover ca. 300 t weapon-grade plutonium. In the second generation, on the contrary, reprocessing has been used to improve the peaceful utilization of nuclear energy, and ca. 1.0 × 105 t of civil high burn-up fuel, which is almost one-third of the total civil SNF evolved worldwide, has been reprocessed mostly in Europe by now (1-3).