The phase equilibria of dilute aqueous solutions are treated separately from those of dilute organic systems due to water's unique structure and hydrogen-bonding characteristics. As a result, traditional predictive methods (UNIFAC, ASOG, etc.) tend to be only moderately successful. In addition to inverse solubility measurements, we describe new direct and indirect techniques for precisely measuring these values which are more accurate. A database is compiled from data measured by using these techniques. The data were evaluated and suspect points removed. The data were correlated linearly with the solute solvatochromic R, , and π*, solute and solvent molar volume, solute vapor pressure, and the solute gas-liquid partition coefficient between hexadecane and an inert gas phase, log L 16 . The correlation fits the data to within an average absolute deviation of 0.294 ln units. The correlation provides a direct and relatively accurate method for estimating Henry's constants and thus limiting activity coefficients of nonelectrolytes in water.
A process for capturing CO 2 from the atmosphere was recently proposed. This process uses a closed cycle of sodium and calcium hydroxide, carbonate, and oxide transformations to capture dilute CO 2 from the atmosphere and to generate a concentrated stream of CO 2 that is amenable to sequestration or subsequent chemical transformations. In one of the process steps, a fossilfueled lime kiln is needed, which reduces the net CO 2 capture of the process. It is proposed to replace the fossil-fueled lime kiln with a modified kiln heated by a high-temperature nuclear reactor. This will have the effect of eliminating the use of fossil fuels for the process and increasing the net CO 2 capture. Although the process is suitable to support sequestration, the use of a nuclear power source for the process provides additional capabilities, and the captured CO 2 may be combined with nuclear-produced hydrogen to produce liquid fuels via Fischer-Tropsch synthesis or other technologies. Conceivably, such plants would be carbon-neutral, and could be placed virtually anywhere without being tied to fossil fuel sources or geological sequestration sites.
At present, most 99 Mo is produced in research, test, or isotope production reactors by irradiation of highly enriched uranium targets. To achieve the denser form of uranium needed for switching from high to low enriched uranium (LEU), targets in the form of a metal foil (~125-150 µm thick) are being developed. The LEU High Density Target Project successfully demonstrated several iterations of an LEU-fission-based Mo-99 technology that has the potential to provide the world's supply of Mo-99, should major producers choose to utilize the technology. Over 50 annular high density targets have been successfully tested, and the assembly and disassembly of targets have been improved and optimized. Two target front-end processes (acidic and electrochemical) have been scaled up and demonstrated to allow for the high-density target technology to mate up to the existing producer technology for target processing. In the event that a new target processing line is started, the chemical processing of the targets is greatly simplified. Extensive modeling and safety analysis has been conducted, and the target has been qualified to be inserted into the High Flux Isotope Reactor, which is considered above and beyond the requirements for the typical use of this target due to high fluence and irradiation duration. FIGURE 1.3 (A) Target Insertion Rig and (B) Target Insertion Rig with Target Showing Cooling Channel on Inside of Target. Up to Three Targets Can Be Placed on Each Rig.
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