Nuclear fuel reprocessing, Purex process

RADIATION EFFECTS IN SPENT NUCLEAR FUEL REPROCESSING 2.1. Purex Process... 

Birkett, J.E. Carrott, M.J. Fox, O.D. Jones, C.J. Maher, C.J. Roube, C.V. Raylor, R.J. Woodhead, D.A. Recent developments in the Purex process for nuclear fuel reprocessing Complexant based stripping for uranium/plutonium separation, Chimia 59 (2005) 898-904. 

In fact, the first description of such a scheme, involving the application of SFE to spent nuclear fuel reprocessing, appeared shortly after publication of these results. Specifically, Smart et al.43 outlined two possible approaches to SC-C02-based reprocessing. In the first, dubbed the wet SF-PUREX process, SC-C02 merely serves as a replacement for the organic solvent (i.e., a normal paraffinic hydrocarbon) used in... 

HNA was incorporated into many nuclear fuel reprocessing plants in the early 1970s replacing the ferrous sulfamate and hydroxylamine sulfate for plutonium reduction because it possessed the proper Pu(IV) to Pu(III) reduction attributes and the gaseous reaction products N2, N2O, and water contributed to the minimization of the volume of solid wastes produced. The French PUREX process at the La Hague site safely uses a mixture of HNA and nitric acid for the reductive stripping phase of plutonium. The British also used HNA in the thermal oxide reprocessing plant (THORP) for over several years (Barney, 1998). 

Herbst, R.S., P.Baron, and M. Nilsson. 2011. Standard and advanced separation Purex processes for nuclear fuel reprocessing. In Kenneth Nash and Greg Lumetta (eds.). Advanced Techniques for Nuclear Fuel Reprocessing and Radioactive Waste Treatment, Chapter 6, pp. 141-175, Woodland Publishing Series in Energy, London, UK. 

FIGURE 2.11 Generic description of the PUREX process. (Based on NBA, Spent nuclear fuel reprocessing flowsheet, OECD Nuclear Energy Agency, Paris, France, NEA/NSC/ WPEC/DOC(2012)15, 2012.)... 

The solvent extraction process that uses TBP solutions to recover plutonium and uranium from irradiated nuclear fuels is called Purex (plutonium uranium extraction). The Purex process provides recovery of more than 99% of both uranium and plutonium with excellent decontamination of both elements from fission products. The Purex process is used worldwide to reprocess spent reactor fuel. During the last several decades, many variations of the Purex process have been developed and demonstrated on a plant scale. 

Reprocessing is based on liquid-liquid extraction for the recovery of uranium and plutonium from used nuclear fuel (PUREX process). The spent fuel is first dissolved in nitric acid. After the dissolution step and the removal of fine insoluble solids, an organic solvent composed of 30% TriButyl Phosphate (TBP) in TetraPropylene Hydrogenated (TPH) or Isopar L is used to recover both uranium and plutonium the great majority of fission products remain in the aqueous nitric acid phase. Once separated from the fission products, back-extraction combined with a reduction of Pu(I V) to Pu(III) allows plutonium to be separated from uranium these two compounds can be recycled.2... 

The centrifugal contactor was first used to reprocess spent nuclear fuel at the SRS in 1966 (Webster et al., 1969). For almost 40 years, this 18-stage 25-cm SRL contactor was used for the extraction and scrub sections (the A-bank) of the PUREX (plutonium-uranium extraction) process at the SRS. Contactor operation stopped when the facility in which they were housed was shut down in 2003. This 18-stage contactor replaced a 24-stage mixer-settler. Mixer-settlers continued to be used for the rest of the processing, as most of the radiation was removed in the A-bank. The ability to... 

The CTH actinide separation process was developed as a possible means to reduce the expected long term dose to man from a geologic repository containing solidified radioactive waste from the reprocessing of spent nuclear fuel The distribution data for the elements present in significant amounts in the high level liquid waste (HLLW) from a Purex plant, the general principles and the flowsheet have been described in detail elsewhere A... 

Reprocessing of nuclear fuel by the Purex process leads to the following amounts of waste per ton of U 1 m HLW (fission products and actinides in HNO3 solution), 3 m MLW as organic solution, 17m MLW as aqueous solution, 90m LLW (aqueous solution). By further processing a volume reduction is achieved 0.1m HLW, 0.2m MLW (organic), 8m MLW (aqueous), 3m LLW (aqueous). 

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