Chemical pretreatment of nuclear wastes refers back to the series of separations approaches used to partition such wastes right into a small quantity of high-level waste for deep geologic disposal and a bigger quantity of low-level waste for disposal in a near-surface facility. Pretreatment of nuclear wastes now saved at numerous U. S. division of strength websites levels from basic solid-liquid separations to extra complicated chemical steps, similar to dissolution of sludges and removing of chosen radionuclides, e. g. , 90Sr, 99Tc, 137CS, and TRU (transuranium) parts. the driver for improvement of chemical pretreatment procedures for nuclear wastes is the commercial good thing about waste minimization as mirrored in decrease bills for near-surface disposal in comparison to the excessive rate of doing away with wastes in a deep geologic repository. This latter subject is expertly and authoritatively mentioned within the introductory paper via J. and L. Bell. Seven papers during this quantity describe numerous separations approaches built or being constructed to pretreat the massive quantity of nuclear wastes kept on the US DOE Hanford and Savannah River websites. those papers contain descriptions of the sort and quantity of significant nuclear wastes saved on the Hanford and Savannah River websites in addition to shortly anticipated innovations for his or her therapy and ultimate disposal. A paper via Strachan et al. discusses chemical and radiolytic mechanisms for the formation and unencumber of probably explosive hydrogen fuel in Tank 241-SY-101 on the Hanford site.