Fast Reactors and Accelerator Driven Systems Knowledge Base

Conference Article: Chemical separations technologies for the US accelarator transmutation of waste programme

J.J. Laidler

Abstract

Management of the spent nuclear fuel generated by the operating commercial reactors in the United States is entering a new phase because it is clear that the continued rate of accumulation of spent fuel is such that the spent fuel inventory will soon exceed the legislated capacity of the proposed Yucca Mountain repository. An integrated chemical separations system has been conceived for the partitioning of this fuel preparatory to transmutation of transuranic elements and long-lived fission products in an accelerator-driven transmuter reactor. A hybrid aqueous/pyrochemical separations system is being developed, with the initial separation done with an aqueous solvent extraction process called UREX. The UREX process extracts uranium, technetium and iodine and directs the transuranic elements and other fission products to the liquid waste stream. The uranium is sufficiently pure that it can be disposed as a low-level waste, while the technetium and iodine are converted into targets for transmutation to stable isotopes. The liquid waste stream containing the transuranics is converted to solid oxide form and the transuranics are separated from the fission products by electrorefining after having been converted to the metallic state. Demonstrations of the process with actual LWR spent fuel are in progress.

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key words: Fast Neutron Spectrum Systems, Nuclear Technology
Reference:
Proceedings of a Committee Meeting (TCM) on “Core Physics and Engineering Aspects of Emerging Nuclear Energy Systems for Energy Generation and Transmutation” held in Argonne, Illinois, U.S.A., 28 November - 1 December 2000
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--1356, pp:164-167