Improved inorganic ion exchange membranes

New method makes solid ion exchange membrane electrolytes for use in hydrocarbon-oxygen and hydrogen-oxygen fuel cells. The membrane is a sintered composite of zirconia, phosphoric acid, and zeolite

Progress in evaluation of radionuclide geochemical information developed by DOE high-level nuclear waste repository site projects. Annual report, October 1984-September 1985. Volume 4

Information pertaining to the potential geochemical behavior of radionuclides at candidate sites for a high-level radioactive waste repository, which is being developed by projects within the Department of Energy (DOE), is being evaluated by Oak Ridge National Laboratory for the Nuclear Regulatory Commission (NRC). During this report period, emphasis was placed on the evaluation of information pertinent to the Hanford site in southeastern Washington. Results on the sorption/solubility behavior of technetium, neptunium, and uranium in the basalt/water geochemical system are summarized and compared to the results of DOE. Also, summaries of results are reported from two geochemical modeling studies: (1) an evaluation of the information developed by DOE on the native copper deposits of Michigan as a natural analog for the emplacement of copper canisters in a repository in basalt, and (2) calculation of the solubility and speciation of radionuclides for representative groundwaters from the Yucca Mountain site in Nevada

Structure-Function Analysis of Human TYW2 Enzyme Required for the Biosynthesis of a Highly Modified Wybutosine (yW) Base in Phenylalanine-tRNA

Posttranscriptional modifications are critical for structure and function of tRNAs. Wybutosine (yW) and its derivatives are hyper-modified guanosines found at the position 37 of eukaryotic and archaeal tRNAPhe. TYW2 is an enzyme that catalyzes α-amino-α-carboxypropyl transfer activity at the third step of yW biogenesis. Using complementation of a ΔTYW2 strain, we demonstrate here that human TYW2 (hTYW2) is active in yeast and can synthesize the yW of yeast tRNAPhe. Structure-guided analysis identified several conserved residues in hTYW2 that interact with S-adenosyl-methionine (AdoMet), and mutation studies revealed that K225 and E265 are critical residues for the enzymatic activity. We previously reported that the human TYW2 is overexpressed in breast cancer. However, no difference in the tRNAPhe modification status was observed in either normal mouse tissue or a mouse tumor model that overexpresses Tyw2, indicating that hTYW2 may have a role in tumorigenesis unrelated to yW biogenesis

Geochemical information for sites contaminated with low-level radioactive wastes: I. Niagara Falls Storage Site

The Niagara Falls Storage Site (NFSS) became radioactively contaminated as a result of wastes that were being stored from operations carried out to recover uranium from pitchblende ore in the 1940s and 1950s. The US Department of Energy (DOE) is considering various remedial action options for the NFSS. This report describes the results of geochemical investigations performed to help provide a quantitative evaluation of the effects of various options. NFSS soil and groundwater samples were characterized; and uranium and radium sorption ratios, as well as apparent concentration limit values, were measured in site soil/groundwater systems by employing batch contact methodology. The results suggest that any uranium which is in solution in the groundwater at the NFSS may be poorly retarded due to the low uranium sorption ratio values and high solubility measured. Further, appreciable concentrations of uranium in groundwater could be attained from soluble wastes. Release of uranium via groundwater migration could be a significant release pathway. Solubilized radium would be expected to be effectively retarded by soil at the NFSS as a result of the very high radium sorption ratios observed. The addition of iron oxyhydroxide to NFSS soils resulted in much higher uranium sorption ratios. Additional field testing of this potential remedial action additive could be desirable. 10 references

Geochemical information for sites contaminated with low-level radioactive wastes. III. Weldon Spring Storage Site

The Weldon Spring Storage Site (WSSS), which includes both the chemical site and the quarry, became radioactively contaminated as the result of wastes that were being stored from operations to recover uranium from pitchblende ores in the 1940s and 1950s. The US Department of Energy (DOE) is considering various remedial action options for the WSSS. This report describes the results of geochemical investigations carried out at Oak Ridge National Laboratory (ORNL) to support these activities and to help quantify various remedial action options. Soil and groundwater samples were characterized, and uranium and radium sorption ratios were measured in site soil/groundwater systems by batch contact methodology. Soil samples from various locations around the raffinate pits were found to contain major amounts of silica, along with illite as the primary clay constituent. Particle sizes of the five soil samples were variable (50% distribution point ranging from 12 to 81 ..mu..m); the surface areas varied from 13 to 62 m/sup 2//g. Elemental analysis of the samples showed them to be typical of sandy clay and silty clay soils. Groundwater samples included solution from Pit 3 and well water from Well D. Anion analyses showed significant concentrations of sulfate and nitrate (>350 and >7000 mg/L, respectively) in the solution from Pit 3. These anions were also present in the well water, but in lower concentrations. Uranium sorption ratios for four of the soil samples contacted with the solution from Pit 3 were moderate to high (approx. 300 to approx. 1000 mL/g). The fifth sample had a ratio of only 12 mL/g. Radium sorption ratios for the five samples were moderate to high (approx. 600 to approx. 1000 mL/g). These values indicate that soil at the WSSS may show favorable retardation of uranium and radium in the groundwater. 13 references, 13 figures, 10 tables

Geochemical information for sites contaminated with low-level radioactive wastes: II. St. Louis Airport Storage Site

The St. Louis Airport Storage Site (SLASS) became radioactively contaminated as a result of wastes that were being stored from operations to recover uranium from pitchblende ores in the 1940s and 1950s. The US Department of Energy is considering various remedial action options for the SLASS under the Formerly Utilized Site Remedial Action Program (FUSRAP). This report describes the results of geochemical investigations, carried out to support the FUSRAP activities and to aid in quantifying various remedial action options. Soil and groundwater samples from the site were characterized, and sorption ratios for uranium and radium and apparent concentration limit values for uranium were measured in soil/groundwater systems by batch contact methodology. The uranium and radium concentrations in soil samples were significantly above background near the old contaminated surface horizon (now at the 0.3/sup -/ to 0.9/sup -/m depth); the maximum values were 1566 ..mu..g/g and 101 pCi/g, respectively. Below about the 6/sup -/m depth, the concentrations appeared to be typical of those naturally present in soils of this area (3.8 +- 1.2 ..mu..g/g and 3.1 +- 0.6 pCi/g). Uranium sorption ratios showed stratigraphic trends but were generally moderate to high (100 to 1000 L/kg). The sorption isotherm suggested an apparent uranium concentration limit of about 200 mg/L. This relatively high solubility can probably be correlated with the carbonate content of the soil/groundwater systems. The lower sorption ratio values obtained from the sorption isotherm may have resulted from changes in the experimental procedure or the groundwater used. The SLASS appears to exhibit generally favorable behavior for the retardation of uranium solubilized from waste in the site. Parametric tests were conducted to estimate the sensitivity of uranium sorption and solubility to the pH and carbonate content of the system

Geochemical information for the West Chestnut Ridge Central Waste Disposal Facility for low-level radioactive waste

Geochemical support activities for the Central Waste Disposal Facility (CWDF) project included characterization of site materials, as well as measurement of radionuclide sorption and desorption isotherms and apparent concentration limit values under site-relevant laboratory test conditions. The radionuclide sorption and solubility information is needed as input data for the pathways analysis calculations to model expected radioactivity releases from emplaced waste to the accessible environment under various release scenarios. Batch contact methodology was used to construct sorption and desorption isotherms for a number of radionuclides likely to be present in waste to be disposed of at the site. The sorption rates for uranium and europium were rapid (> 99.8% of the total radionuclide present was adsorbed in approx. 30 min). With a constant-pH isotherm technique, uranium, strontium, cesium, and curium exhibited maximum Rs values of 4800 to > 30,000 L/kg throughout the pH range 5 to 7. Sorption ratios were generally lower at higher or lower pH levels. Retardation factors for uranium, strontium, and cesium, explored by column chromatographic tests, were consistent with the high sorption ratios measured in batch tests for these radionuclides. The addition of as little as 0.01 M organic reagent capable of forming strong soluble complexes with metals (e.g., ethylenediaminetetraacetic acid (EDTA) or citric acid) was found to reduce the sorption ratio for uranium by as much as two orders of magnitude. Substitution of an actual low-level waste site trench water for groundwater in these tests was found to give a similar reduction in the sorption ratio

Evaluation of DOE Radionuclide Solubility Data and Selected Retardation Parameters: Description of Calculational and Confirmatory Experimental Activities

An experimentally oriented program has been initiated to support the NRC analysis and licensing activities related to high-level nuclear waste repositories. The program will allow the NRC to independently confirm key geochemical values used in the site performance assessments submitted by the DOE candidate repository site projects. Key radionuclide retardation factor values, particularly radionuclide solubility and sorption values under site specific geochemical conditions, are being confirmed. The initial efforts are being directed toward basalt rock/groundwater systems relevant to the BWIP candidate site in the Pasco Basin. Future work will consider tuff (NNWSI candidate site in Yucca Mountain) and salt (unspecified ONWI bedded or domal salt sites) rock/groundwater systems. Initial experimental results with technetium have confirmed the BWIP values for basalt/groundwater systems under oxic redox conditions: high solubility and no sorption. Under reducing redox conditions, however, the experimental work did not confirm the proposed technetium values recommended by BWIP. In the presence of hydrazine to establish reducing conditions, an apparent solubility limit for technetium of about 5E-7 mol/L was encountered; BWIP recommended calculated values of 1E-12 or greater than or equal to 1E-14 mol/L. Experimental evidence concerning sorption of reduced technetium species is incomplete at this time. Equilibrium speciation and saturation indices were calculated for well water data sets from BWIP using the computer code PHREEQUE. Oversaturation was indicated for hematite and quartz in all data sets. Near surface samples were undersaturated with respect to calcite, but most deep samples were oversaturated with respect to calcite and other carbonate minerals