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Chemical treatment of spent nuclear fuel to partition reusable constituents from wastes. Recovery does not eliminate the need for waste conditioning and disposal. This article concerns concepts and material accounting, not operational fissile-separation procedures.

A once-through fuel cycle in which spent nuclear fuel is managed without recovering its constituents for a further fuel irradiation.

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 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.

A useful three-product account is a demonstrated site end state, recovered materials, and wastes requiring disposal or continuing management. It keeps the land outcome distinct from the material streams.

The first product is the land and any retained buildings in the specified nuclear decommissioning end state. Characterisation and final surveys must show that the remaining inventory is consistent with the intended reuse and any retained restrictions. Demolition is a possible means of reaching that state, not its definition. The associated records and final radiological evidence are part of the handover.

The second product is reusable or recyclable material and equipment. Segregation and, where appropriate, decontamination prevent clean bulk material from being unnecessarily mixed with contaminated material. Release from radiological control requires demonstrated radiological clearance; conventional chemical hazards still need their own management.

The third product is waste: both ordinary unrecoverable demolition debris and radioactive waste that remains under control. Activated structures, contaminated components and secondary cleaning wastes may require different treatment and packages. spent nuclear fuel, if still present, requires its own inventory and management route rather than being counted as ordinary scrap. Thus the material outputs can alternatively be tabulated as reusable material, conventional waste and radioactive waste, while the restored site is the overarching project deliverable. The source does not define a unique named three-product taxonomy.^[ref]

uranium recovered from spent nuclear fuel. Its isotopic composition differs from natural uranium; uranium-236 can impose an additional fuel-performance penalty.