Depleted uranium properties

Miller, A.C. (2007). Depleted Uranium Properties, Uses and Health Consequences. Boca Raton, FL Taylor Francis/CRC Press. 

One of the most significant sources of change in isotope ratios is caused by the small mass differences between isotopes and their effects on the physical properties of elements and compounds. For example, ordinary water (mostly Ej O) has a lower density, lower boiling point, and higher vapor pressure than does heavy water (mostly H2 0). Other major changes can occur through exchange processes. Such physical and kinetic differences lead to natural local fractionation of isotopes. Artificial fractionation (enrichment or depletion) of uranium isotopes is the basis for construction of atomic bombs, nuclear power reactors, and depleted uranium weapons. 

Depleted Uranium. In the natural state U is a mixt of isotopes from which two, U23s and U238> are extracted for use in nuclear reactors and weapons. What remains after the extraction is known as depleted uranium which now exists in large quantities and for which few uses have so far been found. One property of U is its high d -it is heavier than Pb — and this has led to the investigation of its military applications... 

Another military use of the actinide metals is in tank armor and armor piercing projectiles. Depleted uranium metal is an extremely dense material, for example, density of a-phase U is 19 g cm, and is only mildly radioactive, half-life of is 4.5 X 10 years. When this metal is incorporated into a projectile, the density and metallic properties allow it to penetrate deeply into heavily armored vehicles. 

Depleted uranium is an excellent metallic substrate for radiation shielding and for armor and ammunition by the military due to its density and pyrophoric properties. Furthermore, the unique ability of uranium-based ammunitions to sharpen themselves upon impact, allowing for deeper penetration of the ammunitions, also makes DU a better substrate for weapons of mass destruction. As such, it is not suprising that the use of DU in military applications is expected to grow. This increased use will no doubt be bolstered by recent scientific studies showing that DU exposure has relatively low adverse health effects, contrary... 

Bleise, A., Danesi, P.R., Burkart, W. (2003). Properties, use and health effects of depleted uranium (DU) a general overview. J. Environ. Radioact. 64 93-112. 

Mitchel, R.E., Sunder, S. (2004). Depleted uranium dust Ifom fired munitions physical, chemical and biological properties. Health Phys. 87 57-67. 

The objective of Materials Chemistry is to provide an overview of the various types of materials, with a focus on synthetic methodologies and relationships between the structure of a material and its overall properties. Each chapter will feature a section entitled Important Materials Applications that will describe an interesting current/future application related to a particular class of material. Topics for these sections include fuel cells, depleted uranium, solar cells, self-healing plastics, and molecular machines e.g., artificial muscles). 

Chemically, natural and depleted uranium are identical. Therefore, the MRLs calculated for chemical effects, based on studies that tested natural uranium, are applicable to the chemical actions of depleted uranium because the nature and extent of chemical toxicity are determined only by chemical properties. 

Bleise a, Danes PR and Burkart W (2003) Properties, Use and Health Effects of Depleted Uranium (DU) — A General Overview. J Env Radioactivity 64 121 — 131... 

Table III shows the properties of the liquid products from the hydrogasification experiments with depleted uranium catalyst. Sulfur percentages in the liquid products were considerably lower than the percentage in the feed, but nitrogen percentages were high. The naphthas became aromatic as the operating temperature was raised from 880° to 1102°F.

Cobalt Molybdate Catalyst. Yields of products from hydrogasifying crude shale oil over cobalt molybdate catalyst at a space velocity of 1.0 volume of oil per volume of catalyst per hour are shown in Table IV, and properties of the liquid products are shown in Table V. The average reaction temperatures from 974° to 1183°F. were higher than those used with depleted uranium catalyst. Consequently, greater gas yields were obtained. However, similar trends were shown in the results obtained with both catalysts. 

Uranium can also be used for mechanical properties, not just the radioactive properties. Depleted uranium is a form of uranium that has no radioactivity, or at least, has negligible radioactivity. The atom is very dense so any material made using this can be mechanically very strong. It has found favor for many military applications such as the skin of tanks. The depleted uranium can re-enforce the metal making it resistant to artillery fire. It can also be used as ballasts on ships, too. 

To simulate the nuclear waste, U02(N03)2 6H20 dissolved in nitric acid solution was used. U02(N03)2 6H20 is a yellow crystalline solid. It contains nitric acid and is mildly chemically toxic. It is non-fissile (depleted) uranium, containing less than 1.0 % U-235, which means that it cannot sustain a nuclear chain reaction. It is radioactive, but chemically stable. Some of the properties are presented in Table 3.4. At all experiments the initial concentration of dioxouranium(VI) in the nitric acid solutions was 0.05 M. The concentration of IJ02 in the two phases was detected by a UV-Vis spectrometer (USB2000+, from Ocean Optics). 

As mentioned earlier, specifications for DU whether it is intended for use in munitions, radiation shielding, or aircraft ballast are difficult to find. In any case, the analytical procedures for its characterization, described earlier for other uranium compounds, are valid also for DU. Dissolution of the metal samples in concentrated nitric acid (HF may be added if residues remain) is required for meticulous analysis of impurities by ICP-OES, ICP-MS, or/and other suitable analytical method. Conversion to UjO in a muffle furnace with steam for impurity determination by DC-arc is also an option. Determination of the H, C, N, O, and S content with dedicated instrumentation may also be carried out. On the other hand, the impurity requirements for DU are not as strictly controlled as they are for other nuclear materials. If the depleted uranium is alloyed, as mentioned earlier to improve the mechanical properties, the concentration of the alloying element must be determined according to specifications. 

Uranium is a heavy metal that forms compounds and complexes of different varieties and solubilities. The chemical action of all isotopes and isotopic mixtures of uranium is identical, regardless of the specific activity (i.e., enrichment), because chemical action depends only on chemical properties. Thus, the chemical toxicity of a given amount or weight of natural, depleted, and enriched uranium is identical. 

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