Global efforts to support non-uranium approaches for 99Mo production, due to the proliferation risks associated with 235U fission-based production methods, have recently taken huge strides towards fruition. Several linear accelerator-based methods are currently in late-stage development that can produce low specific activity 99Mo from enriched 98/100Mo targets. The development of...
Used Nuclear Fuel (UNF) contains transuranic (TRU) elements and numerous fission products as a result of the uranium fission process and neutron activation that occur in commercial light water power reactors. Recent environmental and nuclear proliferation concerns have spawned the development of advanced reprocessing techniques to close the nuclear fuel...
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...
Nowadays selective separation processes are sought after more than ever before. They are indispensable to meet the growing demand for individual rare earth elements, minor actinides partitioned from fission-produced lanthanides, as well as, overall, more concentrated and high-purity products. This research focuses on such separation techniques as solvent extraction which...
Industrial reprocessing of irradiated nuclear fuel (INF) is one of the most complex procedures performed on a large scale; the process is intricate due to the mix of radionuclides present in INF. As a global trend for nuclear power and reprocessing continues, research is geared toward optimizing the extraction of...
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Alena Paulenova
Industrial reprocessing of irradiated nuclear fuel (INF) is one of the
Production of 89Zr serves as a crucial preliminary step for exploring Zr-chelates, determining their stability constants, and advancing radiolabeling methodologies for monoclonal antibody based theranostics. 89Zr is typically produced by the irradiation of natural yttrium targets, a process extensively documented in scientific literature. Two primary methods are employed: the 89Y(p,n)89Zr...
This study investigated gel dosimetry with X-ray CT imaging as a possible means for extracting dose information from a 3D gel dosimeter. Currently Optical CT and MRI are the popular means of dose extraction, but X-ray CT imaging has the advantage of being more convenient and cost effective. The dosimetric...
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Alena Paulenova
This study investigated gel dosimetry with X-ray CT imaging as a
Neptunium, with its rich redox chemistry, has a special position in the chemistry of actinides. With a decades-long history of development of aqueous separation methods for used nuclear fuel (UNF), management of neptunium remains an unresolved issue because of its not clearly defined redox speciation. Neptunium is present in two,...
Uranium dioxide has been used in industry both as a fuel for power reactors and as a target for the production of radioisotopes. One of the most important radioisotopes produced using these targets is molybdenum-99 (Mo-99, 65.94hr half-life), which is the parent isotope to technetium-99m (Tc-99m, 6.01hr half-life), a radioisotope...
Microstructure changes in uranium and uranium/metal alloys due to radiation damage are of great interest in nuclear science and engineering. Titanium has attracted attention because of its similarity to Zr. It has been proposed for use in the second generation of fusion reactors due to its resistance to radiation-induced swelling....
In this work, three isomeric forms of N, N'-diethyl, N, N'-ditolyldipicolinamide (EtTDPA) were synthesized. The elements thorium through americium, which make up a significant portion of the actinides in used nuclear fuel (with the exception of curium), and two fission products, molybdenum and technetium, were tested for their ability to...
Iodine-129 is a key risk driver at sites where nuclear materials have been fabricated or processed, and it is a predominant isotope of concern in long-term waste storage strategies. I-129 exists primarily as iodate in the subsurface at the Hanford Site in south-central Washington State. Between 15 and 40% of...
Carboxylic acids have played an important role in the field of actinide (An) and lanthanide (Ln) separations and the reprocessing of irradiated nuclear fuel. Recent bench-scale experiments have demonstrated that 3-carboxy-3-hydroxypentanedioic acid (citric acid) is a promising aqueous complexant that can effectively aid in the separation of transition metals from...
Chitosan is a biopolymer resulting from the deacetylation of chitin, the second most abundant biopolymer in nature. Chitosan has been successfully used in systems to remove metal ions and other pollutants from wastewater. Chitosan has shown promise as a sorbent for radionuclides in some aqueous waste streams.
The sorption of...
Effective separation of lanthanides (Ln) from the minor actinides (MA) is a crucial technical challenge to closing the nuclear fuel cycle. This separation is a necessary prerequisite to transmute long-lived isotopes of Am and Cm, which will allow a reduction of the repository volume, thermal load, and radiological toxicity of...
Partitioning of trivalent actinides (in particular, americium and curium) from the
fission produced light lanthanides is a major concern of used nuclear fuel reprocessing for
the purposes of waste disposal. Several solvent extraction processes have been developed
to address these chemically difficult separations. The historically employed TALSPEAK
Process utilizes di-2-ethylhexyl...
Pyroprocessing is an advanced technology for recycling used nuclear fuel. Pyrochemical processes encompass a wide range of chemical, physical, and electrochemical methods to partition fission products and other components from used nuclear fuel, which allows for the reuse of the actinides in nuclear fuel. This dissertation investigates two chemical systems...
This thesis presents an approach to develop innovative methods for decontamination and surface protection applicable to naval nuclear ships and potentially, personnel, replacing antiquated techniques. To accomplish this goal, two products manufactured by CBI Polymers, LLC., DeconGel™ 1101 (1101) and a shampoo, DeconGel™ "prototype" (prototype), were tested.
The prototype was...
An alternative extractant for the TRUEX/UNEX process was investigated in solid phase extraction chromatography. The para and ortho isomers of diamides derivatives of dipicolinic acid (N,N'-diethyl-N,N'-ditolyl-dipicolinamide, EtTDPA) have been found in the past to effectively separate actinides from lanthanides in solvent extraction and were successfully impregnated on two uncoated, inert...
The goal of Advanced Fuel Cycle Initiative program is to efficiently separate and recover actinides in attempts to reprocess irradiated nuclear fuel and reduce the necessary storage volume. In order to facilitate large-scale industrial
applications of liquid-liquid separation processes, knowledge of the thermodynamic constants associated with the distribution of metal...