High-level nuclear waste liquids

Horwitz, E. P., Dietz, M. L., Chiarizia, R., Diamond, H., Maxwell, S. L., and Nelson, M. R., Separation and preconcentration of actinides by extraction chromatography using a supported liquid anion exchanger Application to the characterization of high-level nuclear waste solutions, Anal. Chim. Acta, 310, 63-78, 1995. 

Ansari, S.A., Mohapatra, P.K., Raut, D.R., Seshagiri, T.K., Rajeswari, B., and Manchanda, V.K. 2009. Performance of actinide partitioning extractants in hollow fiber supported liquid membrane for the transport of actinides and lanthanides from high level nuclear waste. J. Membr. Sci. 337 304-309. 

Nuclear Waste. NRC defines high level radioactive waste to include (/) irradiated (spent) reactor fuel (2) liquid waste resulting from the operation of the first cycle solvent extraction system, and the concentrated wastes from subsequent extraction cycles, in a facility for reprocessing irradiated reactor fuel and (3) solids into which such liquid wastes have been converted. Approximately 23,000 metric tons of spent nuclear fuel has been stored at commercial nuclear reactors as of 1991. This amount is expected to double by the year 2001. 

In nuclear technology, microfiltration is used either for pretreatment purposes or for concentration of coarse particles after precipitation process. For high-level radioactive wastes the ceramic filters are used, giving for some types of effluents high decontamination and concentration factors. The MF facilities used in nuclear industry to treat liquid radioactive wastes are summarized in Table 30.12. 

High-level radioactive waste— The radioactive material resulting from spent nuclear fuel reprocessing this can include liquid waste directly produced in reprocessing or any solid material derived from the liquid wastes having a sufficient concentration of fission products. 

Nigond, L. Musikas, C Cuillerdier, C. Solv. Extr. Ion Exch., 1994, 12, 297. Madic, C. Hudson, M. J. High Level Liquid Waste Partitioning by Means of Completely Incinerable Extractants, European Commission, Nuclear Science and Technology, EUR18038 EN 1998 p. 208. 

High-level waste (HLW), intermediate-level waste (ILW), and low-level waste (LLW) are produced at all stages of the nuclear fuel cycle as well as in the non-nuclear industry, research institutions, and hospitals. The nuclear fuel cycle produces liquid, solid, and gaseous wastes. Moreover, spent nuclear fuel (SNF) is considered either as a source of U and Pu for re-use or as radioactive waste (Johnson Shoesmith 1988), depending on whether the closed ( reprocessing ) or the open ( once-through ) nuclear fuel cycle is realized, respectively (Ewing, 2004). 

Madic, C., Hudson, C. 1998. High level liquid waste partitioning by means of completely incinerable extractants. EUR 18038 EN. European Commission on Nuclear Science and Technology, Luxembourg. 

Manohar, S., Sharma, J.N., Shah, B.V., Wattal, P.K. 2007. Process development for bulk separation of trivalent actinides and lanthanides from radioactive high-level liquid waste. Nuclear Science and Engineering 156 96-102. 

The INET annular centrifugal contactors are being used to partition high-level liquid waste so that the back end of the nuclear fuel cycle can be simplified. In particular, the TRPO process has been developed at INET for this application (Song, 2000), where TRPO is the extractant in the process solvent. Also known as Cyanex 923, TRPO is a trialkyl phosphine oxide that is made commercially by Cytec Industries (formerly American Cyanamid). It has a high affinity for the actinides. Further... 

High-level waste thus includes the concentrated wastes that arise from reprocessing of commercial or defense nuclear fuel that contain virtually all the fission products and transuranium radionuclides (except plutonium) in spent fuel. However, the definition does not mention the constituents of the waste, and it is only qualitative because concentrated is not quantified and the minimum fuel burnup that would yield high-level waste is not specified. Although the definition given above referred only to liquid (aqueous) waste, it is clear from further discussions in 10 CFR Part 50, Appendix F (AEC, 1970), that AEC intended that high-level waste also would include concentrated solid waste derived from liquid high-level waste that was suitable for permanent disposal. 

High-level waste is the primary waste (either liquid or solid) that arises from chemical reprocessing of spent nuclear fuel. 

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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