Actinides from nuclear fuel waste

Mclsaac, L. D. and Schulz, W. W. Removal of Actinides from Nuclear Fuel Reprocessing Waste Solution with Bidentate Organophosphorus Extractants in "Transplutonium 1975,"... 

Separation of Actinides from High-level Waste (HLW). From the point of view of seeking a possible approach to the ultimate disposal of the HLW from the reprocessing of spent nuclear fuels, processes of solvent extraction and ion-exchange techniques have been studied to recover both americium and lanthanides from the HLW and to separate those subsequently. 

Haug, H. 0., "Production, Disposal, and Relative Toxicity of Long-Lived Fission Products and Actinides in the Radioactive Wastes from Nuclear Fuel Cycles," (in German), KFK-2022, translated as 0RNL-tr-it302, Oak Ridge National Laboratory,... 

There are many examples of the studies on SLM for nuclear applications in the literature. SLMs were tested for high-level radioactive waste treatment combined with removal of actinides and other fission products from the effluents from nuclear fuel reprocessing plants. The recovery of the species, such as uranium, plutonium, thorium, americium, cerium, europium, strontium, and cesium, was investigated in vari-ons extracting-stripping systems. Selective permeation... 

Nuclear Waste Reprocessing. Liquid waste remaining from processing of spent reactor fuel for military plutonium production is typically acidic and contains substantial transuranic residues. The cleanup of such waste in 1996 is a higher priority than military plutonium processing. Cleanup requires removal of long-Hved actinides from nitric or hydrochloric acid solutions. The transuranium extraction (Tmex) process has been developed for... 

The counting techniques described in this paper are also readily applicable to studies of "hot radioactive waste (z.e.j radioactive waste from reprocessed nuclear fuel). With this type of material, the cesium can be analyzed as 30-y (662-keV y), the RE as 13-y Eu (964-keV and 1408-keV y), strontium as 28-y Sr (after chemical separation and beta counting), and the actinides by group separation and alpha counting. 

The major repository of transuranic elements entering aquatic systems is the bed sediment (1-4). A significant portion is thought to arrive at the bed sediment surface as a result of association with, and subsequent settling of, suspended particulate matter. Concentrations of plutonium and americium in sediments relative to those in water reportedly range from 1 x IO" to 3 X 10 (32,33,34). Little information is currently available for other actinides of interest relative to nuclear fuel cycle wastes (Th, U, Cm and Np). 

As no technology can selectively transmute minor actinides to a degree meaningful for waste management while they are contained in the spent nuclear fuel, these elements must be separated from the neutron-absorbing elements before being properly transmuted. In the case of trivalent minor actinides, this preliminary step is further necessary because of the following reasons ... 

Solvent extraction separates heavy metals (in particular, the actinides) from lighter metals and from each other and has been an important tool for nuclear chemistry over the last 60 years. As seen in the other chapters of this book, solvent-extraction chemistry remains of vital interest for nuclear fuel reprocessing and for the cleanup and segregation of nuclear waste. 

The third fact is that spent nuclear fuel is not waste. Spent nuclear fuel contains 2% to 3% waste, but is about 97% recoverable uranium and plutonium. Each bundle has the potential electric energy equivalent of more than 10 million barrels of oil. High-level nuclear wastes consist of fission products and actinides that are extracted from spent fuel, but not saved for commercial use or research. Spent fuel may be temporarily stored until it is reprocessed to separate the waste from the valuable plutonium and uranium. The remaining glassified waste will then be permanently entombed. 

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... 

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