The fission products of technetium and zirconium have historically been problematic in the reprocessing of spent nuclear fuel by solvent extraction using tributyl phosphate (TBP) containing solvents. One of the reasons for this is that the routing of zirconium and technetium becomes difficult to control due to co-extraction mechanisms with other elements/species in the dissolved spent fuel liquors and through alternative extraction pathways that can occur with the presence of solvent degradation products. Consequently, solvent extraction processes based on the PUREX (Plutonium Uranium Redox EXtraction) process incorporate various strategies to ensure these fission products are not present in the final product streams, increasing plant footprints and operational costs. Next generation spent nuclear fuel reprocessing should minimise the need for such scrubbing operations by applying a complete and thorough understanding of the distribution behaviour of technetium and zirconium to optimise the separations chemistry for higher burn up spent fuels from advanced reactor systems that contain higher inventories of fission products. A substantial body of work exists regarding the distribution behaviour of technetium and zirconium with phosphorus based extractants, but studies have tended to be fragmented using various extraction conditions and approaches. This review collates and reviews these data, supporting the development of predictive process models whilst making recommendations for improved control of technetium and zirconium in an advanced PUREX process. Key findings from this review include the significant increase of technetium distribution ratios by coextraction with zirconium. The distribution ratios of zirconium are also seen to increase with increasing technetium concentrations when zirconium is present with technetium through a synergistic effect. To achieve full decontamination of the U/Pu product stream, significant process modifications are required, which can be achieved by the introduction of scrubbing steps or the saturation of the organic phase with uranium. The use of holdback reagents may improve decontamination factors, but further experimental research is required. High acid scrubs to reject technetium are established options and already used at the industrial scale at La Hague (France).

锝和锆的裂变产物历来在乏核燃料的后处理中一直存在问题，即使用含有溶剂的磷酸三丁酯 (TBP) 进行溶剂萃取。造成这种情况的原因之一是锆和锝的路线变得难以控制，这是由于与溶解的乏燃料液中的其他元素/物种的共提取机制以及通过存在溶剂降解产物时可能发生的替代提取途径. 因此，基于 PUREX（钚铀氧化还原萃取）工艺的溶剂萃取工艺采用了各种策略，以确保这些裂变产物不存在于最终产品流中，从而增加了工厂占地面积和运营成本。下一代乏核燃料后处理应通过对锝和锆分布行为的全面和透彻了解来优化分离化学，以从含有较高裂变存量的先进反应堆系统中获得较高燃耗的乏燃料，从而最大限度地减少对此类洗涤操作的需求产品。关于锝和锆在磷基萃取剂中的分布行为方面存在大量工作，但使用各种萃取条件和方法的研究趋于零散。本次审查整理和审查这些数据，支持预测过程模型的开发，同时提出改进先进 PUREX 过程中锝和锆控制的建议。本次审查的主要发现包括通过与锆共萃取显着增加锝分布比。当锆与锝通过协同效应存在时，锆的分布比也随着锝浓度的增加而增加。为了实现 U/Pu 产品流的完全净化，需要对工艺进行重大修改，这可以通过引入洗涤步骤或用铀饱和有机相来实现。使用滞留试剂可能会提高去污因子，但需要进一步的实验研究。去除锝的高酸洗涤是既定的选择，并已在拉海牙（法国）以工业规模使用。当锆与锝通过协同效应存在时，锆的分布比也随着锝浓度的增加而增加。为了实现 U/Pu 产品流的完全净化，需要对工艺进行重大修改，这可以通过引入洗涤步骤或用铀饱和有机相来实现。使用滞留试剂可能会提高去污因子，但需要进一步的实验研究。去除锝的高酸洗涤是既定的选择，并已在拉海牙（法国）以工业规模使用。当锆与锝通过协同效应存在时，锆的分布比也随着锝浓度的增加而增加。为了实现 U/Pu 产品流的完全净化，需要对工艺进行重大修改，这可以通过引入洗涤步骤或用铀饱和有机相来实现。使用滞留试剂可能会提高去污因子，但需要进一步的实验研究。去除锝的高酸洗涤是既定的选择，并已在拉海牙（法国）以工业规模使用。需要对工艺进行重大修改，这可以通过引入洗涤步骤或用铀饱和有机相来实现。使用滞留试剂可能会提高去污因子，但需要进一步的实验研究。去除锝的高酸洗涤是既定的选择，并已在拉海牙（法国）以工业规模使用。需要对工艺进行重大修改，这可以通过引入洗涤步骤或用铀饱和有机相来实现。使用滞留试剂可能会提高去污因子，但需要进一步的实验研究。去除锝的高酸洗涤是既定的选择，并已在拉海牙（法国）以工业规模使用。