Thesis (Ph. D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (March 2, 2007) Vita. Includes bibliographical references.

Spent nuclear fuel (SNF) resultant from the generation of nuclear power is a chemically and radiologically diverse system which is advantageous to chemically process prior to geologic disposal. Hydrometallurgy is the primary technology for chemical processing for light water reactor spent fuels, where spent fuel is dissolved in an acid for liquid based separations. The primary means for recovery of desired metals from the SNF solution is liquid-liquid extraction which is based on distribution (partitioning) of the metal ions between two immiscible phases based on thermodynamic favorability. One of the means of increasing this favorability is by designing extractant molecules to be either "harder" or "softer" bases, which will more preferentially extract harder or softer metal ions respectively. This technique is used in designing extractant molecules for targeted extraction as actinides are slightly softer than lanthanides, and precious metals produced in significant quantities from the fission process are especially soft metals. The work performed in this thesis involved the synthesis of a novel soft electron donor organic extractant molecule for testing of targeted soft metal extraction. The molecule synthesized was bis-dibutanethiolthiophosphinato-methane, or S6, a bidentate neutral extractant molecule with significant thiolysis for a softer electron environment. The synthesis technique was refined and the molecule composition and structure was confirmed by ¹H NMR, ³¹P NMR, and elemental analysis. Two metal groups, f-elements (actinides and lanthanides) and soft transition metals were tested for their extractability from nitric acid solutions into an S6 solution in n-dodecane. Aqueous solutions of nitric acid and n-dodecane as an organic diluent are typical liquid-liquid extraction conditions in spent nuclear fuel reprocessing. As extraction experiments were performed with radiotracers, for the soft metal extraction experiment, a mixture of the selected metals was neutron-activated in the OSU TRIGA reactor, as was europium to create a lanthanide radiotracer. Actinides and lanthanides were not seen to effectively extract into the organic or form a precipitate at all, making their partitioning with this extractant seemingly ineffective. Through gamma spectroscopy of an irradiated metal solution post-extraction, it is seen that only silver and palladium preferentially complex in the mixed metal samples into an insoluble organic ligand, dropping out of solution. This effect was more pronounced at higher acid concentrations, but silver was seen to slightly extract to the organic phase at all acid concentrations as well. This testing has shown that the S6 extractant can be used to recover silver and palladium from a mixed metal aqueous solution, such as one resultant from advanced spent nuclear fuel reprocessing operations. This result shows promise for future development of sulfur based organophosphate ligands for targeted extraction of precious metals from solutions. / Graduation date: 2013

A series of fuel cycle simulations were performed using CEA's reactor physics code ERANOS 2.0 to analyze the transmutation performance of the Subcritical Advanced Burner Reactor (SABR). SABR is a fusion-fission hybrid reactor that combines the leading sodium cooled fast reactor technology with the leading tokamak plasma technology based on ITER physics. Two general fuel cycles were considered for the SABR system. The first fuel cycle is one in which all of the transuranics from light water reactors are burned in SABR. The second fuel cycle is a minor actinide burning fuel cycle in which all of the minor actinides and some of the plutonium produced in light water reactors are burned in SABR, with the excess plutonium being set aside for starting up fast reactors in the future. The minor actinide burning fuel cycle is being considered in European Scenario Studies. The fuel cycles were evaluated on the basis of TRU/MA transmutation rate, power profile, accumulated radiation damage, and decay heat to the repository. Each of the fuel cycles are compared against each other, and the minor actinide burning fuel cycles are compared against the EFIT transmutation system, and a low conversion ratio fast reactor.

No description available.

Thesis (doctoral)--Delft University of Technology, 2007. / "Proefschrift ter verkrijging van de graad van doctor aan de Technische Universiteit Delft." Includes bibliographical references (p. 120-128) and index.

Thesis (doctoral)--Delft University of Technology, 2007. / "Proefschrift ter verkrijging van de graad van doctor aan de Technische Universiteit Delft." Includes bibliographical references (p.120-128) and index.

Thesis (doctoral)--Delft University of Technology, 2007. / "Proefschrift ter verkrijging van de graad van doctor aan de Technische Universiteit Delft." Includes bibliographical references (p.120-128) and index.

In the late 1970's, emphasis on non-proliferation forced suspension of all commercial spent-fuel reprocessing. The spent-fuel storage problem plaguing the nuclear industry can be alleviated by reprocessing. For commercial spentfuel reprocessing to again become a reality, a process is needed to reform reprocessing operations such that non-proliferation goals are satisfied. To satisfy these goals, the existing process which generates plutonium-nitrate solution must be altered to generate plutonium-uranium oxide powder. The COPRECAL process is designed to produce this solid. The COPRECAL process allows uranium and plutonium to be extracted from spent-fuel for reuse in commercial lightwater reactors. The COPRECAL process is unique in that no pure plutonium is ever present throughout the process, whether the COPRECAL process is intrinsically vulnerable to plutonium diversion is the object of this work. A simulation model of the COPRECAL process is presented which employs state-of-the-art instrumentation to measure in-process plutonium through the simulated passage of time. Plutonium diversion schemes are incorporated into the model. After simulated thefts, model output statistics are plotted on control charts and analyzed. Results show need for major design changes in the COPRECAL process. / Master of Science / incomplete_metadata

Thesis: M.S., Massachusetts Institute of Technology, Department of Nuclear Engineering, 1977 / Includes bibliographical references. / M.S. / M.S. Massachusetts Institute of Technology, Department of Nuclear Engineering

Call number: LD2668 .T4 1985 M66 / Master of Science