Tracer studies plutonium

Livingstone et al. [87] carried out double tracer studies to optimise conditions for the radiochemical separation of plutonium from large volumes of seawater. 

Since 1958, more than 20 nuclides of actinides ranging from neptunium to einsteinium were identified and prepared for tracer studies. From neutron-irradiated uranium samples 2 9Np was adjusted to the pentavalent state and separated by TBP extraction from perchloric acid media. Plutonium-239 was separated by TBP extraction from nitric acid solution followed by anion exchange in a system of Dowex-1 resin and nitric acid. Neptunium-237 was separated from a spent fuel solution of JRR-1 (Japan Research Reactor -1) using anion exchange and TBP extraction. The TBP extraction in the hydrochloric acid medium is a simple and effective technique to purify neptunium from plutonium contamination. On the other hand, both anion exchange and solvent extraction with HDEHP could be used to separate tracer scale plutonium from irradiated neptunium targets. 

Applicability of radioactive tracer tests to actual radionuclide measurements is always in question because the radionuclide in the sample may be in a different chemical or physical form. If the radionuclide has multiple oxidation states in nature, e.g., iodine or plutonium, a tracer study will be applicable only if the initial step in the procedure provides for the interchange of all possible oxidation states, or if tracers have been used in all possible oxidation states. Tests can become even more elaborate if the radionuclide of interest is an integral part of a solid sample matrix, e.g., biological material or soil. 

Some work has also been reported on a californium dipivaloylmethanato complex, where the volatility of the complex was compared to complexes of other lanthanides and actinides [151]. These tracer studies suggested that the californium complex deposited at lower temperatures than the americium or plutonium complexes. 

Although the outline of a chemical separation process could be obtained by tracer-scale investigations, the process could not be defined with certainty until study of it was possible at the actual separation plants. Therefore, the question in the summer of 1942, was as follows How could any separations process be tested at the concentration of plutonium that would exist several years later in the production plants when, at this time, there was not even a microgram of plutonium available This problem was solved through an unprecedented series of experiments encompassing two major objectives. First, it was decided to attempt the production... 

Studies of ligands which might provide specificity in binding to various oxidation states of plutonium seems a particularly promising area for futher research. If specific ion electrodes could be developed for the other oxidation states, study of redox reactions would be much facilitated. Fast separation schemes which do not change the redox equilibria and function at neutral pH values would be helpful in studies of behavior of tracer levels of plutonium in environmental conditions. A particularly important question in this area is the role of PuOj which has been reported to be the dominant soluble form of plutonium in some studies of natural waters (3,14). 

Pu-242 samples are available in enrichments ranging from 99.9+% to 95% production-grade material ranges from 85% to 95%. Uses are for the study of plutonium physical properties and as a mass spectroscopy tracer and standard. 

From our tracer experiments, the distribution coefficient of Pu(IV) is directly proportional to [HDEHP]2 and is inversely proportional to [H+]2. The capacity experiments show that there are four molecules of HDEHP and one plutonium ion in a molecule of extracted compound. From this, we conclude that HDEHP is a dimer in the concentration range studied. The proposed extraction mechanism is as follows ... 

Dogs exposed to radium to establish coefficients for plutonium produced data that showed the best way to translate data to humans was to use a two-mutation model to calculate radiation risks to supplement published risk estimates (Bijwaard, 2006 Bijwaard and Dekkers, 2007). The total exposure resulting from a 5 mGi administration of 18F fluoroethyl cyanophenoxy methyl piperidine 18F SFE as a tracer show it to be safe in human positron emission tomography (PET) imaging studies (Waterhouse et al, 2006). 

Although the existence of a volatile higher fluoride of plutonium had been surmised from tracer experiments, positive evidence of the existence of PuF6 was obtained by Florin (31) who first prepared the compound. An investigation of the preparation and properties of PuF6 was also conducted by Mandleberg et al. (58). but in recent years the compound has been most intensively studied by Weinstock and his collaborators. Plutonium hexafluoride can be prepared by a variety of procedures similar to those used for the preparation of uranium hexafluoride. The most widely used method consists in the fluorination of plutonium tetrafluoride with elemental fluorine. Whereas uranium hexafluoride can be prepared by the analogous reaction at 300°, and neptunium hexafluoride at 500°, the preparation of plutonium hexafluoride by this reaction appears to require a... 

Radioactive heavy elements such as uranium, thorium, or plutonium are used as nuclear fuel radium is used in the radiography of metals and radon is used as a surface label to study surface reactions, as well, in the determination of radium or thorium. Among the lighter isotopes, Ni is used in electron capture detectors for GC analysis, in radiocarbon dating and as a tracer, and tritium in nuclear fusion and as a tracer in the studies of reactions. Many radioactive elements are used as a source of radiation, in medicine to diagnose disease, and for treatment. 

Laboratory. The isotope produced was the 20-hour Fm. During 1953 and early 1954, while discovery of elements 99 and 100 was withheld from publication for security reasons, a group from the Nobel Institute of Physics in Stockholm bombarded with O ions, and isolated a 30-min a-emitter, which they ascribed to 100, without claiming discovery of the element. This isotope has since been identified positively, and the 30-min half-life confirmed. The chemical properties of fermium have been studied solely with tracer amounts, and in normal aqueous media only the (III) oxidation state appears to exist. The isotope and heavier isotopes can be produced by intense neutron irradiation of lower elements such as plutonium by a process of successive neutron capture interspersed with beta decays until these mass numbers and atomic numbers are reached. Twenty isotopes and isomers of fermium are known to exist. Fm, with a half-life of about 100.5 days, is the longest lived. °Fm, with a half-life of 30 min, has been shown to be a product of decay of Element 102. It was by chemical identification of Fm that production of Element 102 (nobelium) was confirmed. Fermium would probably have chemical properties resembling erbium. 

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