= Solution
\b[Conceptual scope:] the safe account below describes the functions of <spent nuclear fuel> management and the chemical basis of partitioning. It does not supply an ordered fissile-separation flowsheet, reagents, process conditions or purification instructions. In particular, the requested operational eight-step separation scheme is outside this answer's scope.
Eight useful functional objectives are: receiving and identifying the <spent nuclear fuel>; managing residual <decay heat>; providing <radioactive material confinement> and <radiation shielding>; establishing the chemical and radiological inventory; partitioning reusable constituents from waste at a conceptual level; maintaining accountable control of recovered materials; conditioning solid and liquid wastes; and retaining or treating <radioactive effluents>. These are \b[management and containment functions], not a claim that the question specifies one universal eight-stage plant design. Several occur throughout a facility's operation rather than sequentially.
The chemical principle of <uranium>/<plutonium> partitioning is that an element's <oxidation state> and <complexation> affect its <chemical speciation>, <solubility> and relative affinity for immiscible phases. <solvent extraction> can therefore separate elements whose chemistry differs, even though it does not distinguish <uranium> <isotopes> by this chemical selectivity. A recovery operation must account for the accompanying <fission products>, contaminated process materials and secondary wastes; the recovered material is only one output. <radioactive material confinement>, remote handling and <nuclear material accountancy> remain necessary because chemical partitioning redistributes both radioactive and fissile inventories.
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