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Coupling Sorption to Soil Weathering During Reactive Transport: Impacts of Mineral Transformation and Sorbent Aging on Contaminant Speciation and Mobility

Description: This project aimed for a predictive-mechanistic understanding of the coupling between mineral weathering and contaminant (Cs, Sr, I) transport/fate in caustic waste-impacted sediments. Based on our prior studies of model clay mineral systems, we postulated that contaminant uptake to Hanford sediments would reflect concurrent adsorption and co-precipitation effects. Our specific objectives were: (1) to assess the molecular-scale mechanisms responsible for time-dependent sequestration of contaminants (Cs, Sr and I) during penetration of waste-induced weathering fronts; (2) to determine the rate and extent of contaminant release from the sorbed state; (3) to develop a reactive transport model based on molecular mechanisms and macroscopic flow experiments [(1) and (2)] that simulates adsorption, aging, and desorption dynamics. Progress toward achieving each of these objectives is discussed below. We observed unique molecular mechanisms for sequestration of Sr, Cs and I during native silicate weathering in caustic waste. Product solids, which included poorly crystalline aluminosilicates and well-crystallized zeolites and feldspathoids, accumulate contaminant species during crystal growth.
Date: October 30, 2009
Creator: Chorover, J.; Mueller, K. T.; O'Day, P. A.; Serne, R. J. & Steefel, C. I.
Partner: UNT Libraries Government Documents Department

TECHNETIUM SORPTION MEDIA REVIEW

Description: This report presents information and references to aid in the selection of 99Tc sorption media for feasibility studies regarding the removal of 99Tc from Hanford's low activity waste. The report contains literature search material for sorption media (including ion exchange media) for the most tested media to date, including SuperLig 639, Reillex HPQ, TAM (Kruion), Purolite A520E and A530E, and Dowex 1X8. The U.S. Department of Energy (DOE), Office of River Protection (ORP) is responsible for management and completion of the River Protection Project (RPP) mission, which comprises both the Hanford Site tank farms and the Waste Treatment and Immobilization Plant (WTP). The RPP mission is to store, retrieve and treat Hanford's tank waste; store and dispose of treated wastes; and close the tank farm waste management areas and treatment facilities in a safe, environmentally compliant, cost-effective and energy-effective manner.
Date: August 25, 2011
Creator: JB, DUNCAN; SE, KELLY; RA, ROBBINS; RD, ADAMS; MA, THORSON & CC, HAASS
Partner: UNT Libraries Government Documents Department

LABORATORY REPORT ON THE REMOVAL OF PERTECHNETATE FROM TANK 241-AN-105 SIMULANT USING PUROLITE A530E

Description: This report documents the laboratory testing and analyses as directed under the test plan, LAB-PLN-11-00010, Evaluation of Technetium Ion Exchange Material against Hanford Double Shell Tank Supernate Simulate with Pertechnetate. Technetium (Tc-99) is a major fission product from nuclear reactors, and because it has few applications outside of scientific research, most of the technetium will ultimately be disposed of as nuclear waste. The radioactive decay of Tc-99 to ruthenium 99 (Ru-99) produces a low energy {beta}{sup -} particle (0.1 MeV max). However, due to its fairly long half-life (t{sub 1/2} = 2.13E05 years), Tc-99 is a major source of radiation in low-level waste (UCRL-JRNL-212334, Current Status of the Thermodynamic Data for Technetium and its Compounds and Aqueous Species). Technetium forms the soluble oxy anion, TcO{sub 4}{sup -} under aerobic conditions. This anion is very mobile in groundwater and poses a health risk (ANL, Radiological and Chemical Fact Sheets to Support Health Risk Analyses for Contaminated Areas). It has been demonstrated that Purolite{reg_sign} A530E is highly effective in removing TcO{sub 4}{sup -} from a water matrix (RPP-RPT-23199, The Removal of Technetium-99 from the Effluent Treatment Facility Basin 44 Waste Using Purolite A-530E, Reillex HPQ, and Sybron IONAC SR-7 Ion Exchange Resins). Purolite{reg_sign} A530E is the commercial product of the Oak Ridge National Laboratory's Biquat{trademark} resin (Gu, B. et. ai, Development of Novel Bifunctional Anion-Exchange Resins with Improved Selectivity for Pertechnetate Sorption from Contaminated Groundwater). Further work has demonstrated that technetium-loaded A530E achieves a leachability index in Cast Stone of 12.5 (ANSI/ASN-16.1-2003, Measurement of the Leachability of Solidified Low-Level Radioactive Wastes by a Short-term Test Procedure) as reported in RPP-RPT-39195, Assessment of Technetium Leachability in Cement-Stabilized Basin 43 Groundwater Brine. This effort falls under the technetium management initiative and will provide data for those who will make decisions on the handling and ...
Date: April 17, 2012
Creator: JB, DUNCAN; HAGERTY KJ, MOORE WP & JM, JOHNSON
Partner: UNT Libraries Government Documents Department

Recent International R&D Activities in the Extraction of Uranium from Seawater

Description: A literature survey has been conducted to collect information on the International R&D activities in the extraction of uranium from seawater for the period from the 1960s till the year of 2010. The reported activities, on both the laboratory scale bench experiments and the large scale marine experiments, were summarized by country/region in this report. Among all countries where such activities have been reported, Japan has carried out the most advanced large scale marine experiments with the amidoxime-based system, and achieved the collection efficiency (1.5 g-U/kg-adsorbent for 30 days soaking in the ocean) that could justify the development of industrial scale marine systems to produce uranium from seawater at the price competitive with those from conventional uranium resources. R&D opportunities are discussed for improving the system performance (selectivity for uranium, loading capacity, chemical stability and mechanical durability in the sorption-elution cycle, and sorption kinetics) and making the collection of uranium from seawater more economically competitive.
Date: March 15, 2010
Creator: Rao, Linfeng
Partner: UNT Libraries Government Documents Department

The Effect of Organic Ligands on the Sorption of Neodymium, Gadolinium and Uranium onto Nontronite and Goethite

Description: The sorption of the rare earth elements (REE) Nd(III) and Gd(III) onto goethite in the presence of Suwannee River fulvic acid in 0.1 m NaCl solutions at 25 ºC was investigated quantitatively. The experiments involved batch titrations whereby the concentrations of REE and/or fulvic acid remaining in solution were determined as a function of pH. In the absence of fulvic acid, removal of REE from solution is enhanced in the presence of goethite over the pH range from 6 to 8, compared to the unary system (REE only) in which precipitation of an amorphous hydroxide occurred at pH greater than or equal to 8. In the absence of REE, removal of fulvic acid from solution is enhanced in the presence of goethite in the pH range from 2 to 8 at least 9, compared to a unary (fulvic acid only) system. The presence of fulvic acid at concentrations from 10 to 50 ppm enhanced REE sorption onto goethite slightly at pH less than 7, but had no discernable effect at higher pH values. Fulvic acid at a concentration of 100 ppm exhibited a greater enhancement of REE sorption at pH < 7, but inhibited REE sorption slightly at pH > 7. Experiments investigating the effect of sorption of REE onto goethite by citrate were also performed. However, these studies were not completed owing to experimental difficulties. The results obtained in this study represent an important contribution to the ultimate goal of predicting the mobility of trivalent REE (and analogous trivalent actinides) in the presence of natural organic matter and goethite.
Date: June 12, 2007
Creator: Wood, Scott A.
Partner: UNT Libraries Government Documents Department

Actinide Sorption in Rainier Mesa Tunnel Waters from the Nevada Test Site

Description: The sorption behavior of americium (Am), plutonium (Pu), neptunium (Np), and uranium (U) in perched Rainier Mesa tunnel water was investigated. Both volcanic zeolitized tuff samples and groundwater samples were collected from Rainier Mesa, Nevada Test Site, NV for a series of batch sorption experiments. Sorption in groundwater with and without the presence of dissolved organic matter (DOM) was investigated. Am(III) and Pu(IV) are more soluble in groundwater that has high concentrations of DOM. The sorption K{sub d} for Am(III) and Pu(IV) on volcanic zeolitized tuff was up to two orders of magnitude lower in samples with high DOM (15 to 19 mg C/L) compared to samples with DOM removed (&lt; 0.4 mg C/L) or samples with naturally low DOM (0.2 mg C/L). In contrast, Np(V) and U(VI) sorption to zeolitized tuff was much less affected by the presence of DOM. The Np(V) and U(VI) sorption Kds were low under all conditions. Importantly, the DOM was not found to significantly sorb to the zeolitized tuff during these experiment. The concentration of DOM in groundwater affects the transport behavior of actinides in the subsurface. The mobility of Am(III) and Pu(IV) is significantly higher in groundwater with elevated levels of DOM resulting in potentially enhanced transport. To accurately model the transport behavior of actinides in groundwater at Rainier Mesa, the low actinide Kd values measured in groundwater with high DOM concentrations must be incorporated in predictive transport models.
Date: December 17, 2007
Creator: Zhao, P.; Zavarin, M.; Leif, R.; Powell, B.; Singleton, M.; Lindvall, R. et al.
Partner: UNT Libraries Government Documents Department

TMVOC, A Numerical Simulator for Three-Phase Non-isothermal Flowsof Multicomponent Hydrocarbon Mixtures in Variably SaturatedHeterogeneous Media

Description: TMVOC is designed for studying subsurface contamination by volatile organic compounds (VOCs), such as hydrocarbon fuels and industrial solvents. It can model the one-, two-, or three-dimensional migration of non-aqueous phase liquids (NAPLs) through the unsaturated and saturated zones, the formation of an oil lens on the water table, the dissolution and subsequent transport of VOCs in groundwater, as well as the vaporization and migration of VOCs in the interstitial air of the unsaturated zone, and the reversible sorption of VOCs on the rock matrix of a porous medium. TMVOC accounts for differences in aqueous solubility and volatility of different VOCs that may be present in a NAPL. Thermal remediation treatments such as steam injection or electric resistance heating and associated phase change and flow effects can also be modeled. A simple half-life model for biodegradation is included as well.
Date: August 20, 2005
Creator: Pruess, Karsten & Battistelli, Alfredo
Partner: UNT Libraries Government Documents Department

Geochemical Data Package for Performance Assessment Calculations Related to the Savannah River Site

Description: The Savannah River Site disposes of certain types of radioactive waste within subsurface-engineered facilities. One of the tools used to establish the capacity of a given site to safely store radioactive waste (i.e., that a site does not exceed its Waste Acceptance Criteria) is the Performance Assessment (PA). The objective of this document is to provide the geochemical values for the PA calculations. This work is being conducted as part of the on-going maintenance program that permits the PA to periodically update existing calculations when new data becomes available. Because application of values without full understanding of their original purpose may lead to misuse, this document also provides the geochemical conceptual model, approach used for selecting the values, the justification for selecting data, and the assumptions made to assure that the conceptual and numerical geochemical models are reasonably conservative (i.e., reflect conditions that will tend to predict the maximum risk to the hypothetical recipient). The geochemical parameters describe transport processes for 38 elements (&gt;90 radioisotopes) potentially occurring within eight disposal units (Slit Trenches, Engineered Trenches, Low Activity Waste (LAW) Vault, Intermediate Level (ILV) Vaults, TRU-Pad-1, Naval Reactor Waste Pads, Components-in-Grout Trenches, and Saltstone Facility). This work builds upon well-documented work from previous PA calculations (McDowell-Boyer et al. 2000). The new geochemical concepts introduced in this data package are: (1) In the past, solubility products were used only in a few conditions (element existing in a specific environmental setting). This has been expanded to &gt;100 conditions. (2) Radionuclide chemistry in cementitious environments is described through the use of both the Kd and apparent solubility concentration limit. Furthermore, the solid phase is assumed to age during the assessment period (thousands of years), resulting in three main types of controlling solid phases, each possessing a unique set of radionuclide sorption parameters (Kd and ...
Date: February 28, 2006
Creator: Kaplan, D
Partner: UNT Libraries Government Documents Department

SODIUM ALUMINOSILICATE SOLIDS AFFINITY FOR CESIUM AND ACTINIDES

Description: Washed sodium-aluminosilicate (NAS) solids at initial concentrations of 3.55 and 5.4 g/L sorb or uptake virtually no cesium over 288 hours, nor do any NAS solids generated during that time. These concentrations of solids are believed to conservatively bound current and near-term operations. Hence, the NAS solids should not have affected measurements of the cesium during the mass transfer tests and there is minimal risk of accumulating cesium during routine operations (and hence posing a gamma radiation exposure risk in maintenance). With respect to actinide uptake, it appears that NAS solids sorb minimal quantities of uranium - up to 58 mg U per kg NAS solid. The behavior with plutonium is less well understood. Additional study may be needed for radioactive operations relative to plutonium or other fissile component sorption or trapping by the solids. We recommend this testing be incorporated in the planned tests using samples from Tank 25F and Tank 49H to extend the duration to bound expected inventory time for solution.
Date: July 31, 2007
Creator: Peters, T; Bill Wilmarth, B & Samuel Fink, S
Partner: UNT Libraries Government Documents Department

Monitored Natural Attenuation of ino9rganic Contaminants Treatability Study Final Report

Description: The identification and quantification of key natural attenuation processes for inorganic contaminants at D-Area is detailed herein. Two overarching goals of this evaluation of monitored natural attenuation (MNA) as a remediation strategy were (1) to better define the availability of inorganic contaminants as potential sources for transport to groundwater and uptake by environmental receptors and (2) to understand the site-specific mechanisms controlling attenuation of these inorganic contaminants through tandem geochemical and biological characterization. Data collected in this study provides input for more appropriate site groundwater transport models. Significant natural attenuation is occurring at D-Area as evidenced by relatively low aqueous concentrations of constituents of concern (COCs) (Be, Ni, U, and As) at all locations characterized and the decrease in groundwater concentrations with increasing distance from the source. The observed magnitude of decrease in groundwater concentrations of COCs with distance from the D-Area Coal Pile Runoff Basin (DCPRB) could not be accounted for by the modeled physical attenuation processes of dilution/dispersion. This additional attenuation, i.e., the observed difference between the groundwater concentrations of COCs and the modeled physical attenuation, is due to biogeochemical processes occurring at the D-Area. In tandem geochemical and microbiological characterization studies designed to evaluate the mechanisms contributing to natural attenuation, pH was the single parameter found to be most predictive of contaminant attenuation. The increasing pH with distance from the source is likely responsible for increased sorption of COCs to soil surfaces within the aquifer at D-Area. Importantly, because the sediments appear to have a high buffering capacity, the acid emanating from the DCPRB has been neutralized by the soil, and these conditions have led to large Kd values at the site. Two major types of soils are present at D-Area and were evaluated in this study: upland subsurface soils associated with a low pH/high sulfate/metals plume ...
Date: May 19, 2004
Creator: Crapse, K
Partner: UNT Libraries Government Documents Department

DESORPTION BEHAVIOR OF TRICHLOROETHENE AND TETRACHLOROETHENE IN U.S. DEPARTMENT OF ENERGY SAVANNAH RIVER SITE UNCONFINED AQUIFER SEDIMENTS

Description: Sorption is governed by the physico-chemical processes that partition solutes between the aqueous and solid phases in aquifers. For environmental systems, a linear equilibrium relationship between the amount of contaminant in the alternative phases is often assumed. In this traditional approach, the distribution coefficient, or K{sub d}, is a ratio of contaminant associated with the solid phase to the contaminant in the water phase. Recent scientific literature has documented time-dependant behaviors in which more contaminant mass is held in the solid phase than predicted by the standard model. Depending on the specific conceptualization, this has been referred to as nonlinear sorption, time-variable sorption, or ''irreversible sorption''. The potential impact of time-variable sorption may be beneficial or detrimental depending on the specific conditions and remediation goals. Researchers at the Pacific Northwest National Laboratory (PNNL) have been studying this process to evaluate how various soil types will affect this process for sites contaminated with chlorinated solvents. The results described in this report evaluate sorption-desorption of trichloroethylene (TCE) and tetrachloroethylene (PCE) in Savannah River Site (SRS) soils. The results of this study will be combined with ongoing PNNL research to provide a more comprehensive look at this process and its impact on contaminant plume stability and sustainability. Importantly, while the results of the study documented differences in sorption properties between two tested SRS soils, the data indicated that ''irreversible sorption'' is not influencing the sorption-desorption behaviors of TCE and PCE for these soils.
Date: January 10, 2007
Creator: Vangelas, K; Robert G. Riley, R; James E. Szecsody, J; A. V. Mitroshkov, A; C. F. Brown, C & Brian02 Looney, B
Partner: UNT Libraries Government Documents Department

Determination of Fissile Loadings onto Monosodium Titanate (MST) under Conditions Relevant to the Actinide Removal Process Facility

Description: This report describes the results of an experimental study to measure the sorption of fissile actinides on monosodium titanate (MST) at conditions relevant to operation of the Actinide Removal Process (ARP). The study examined the effect of a single contact of a large volume of radionuclide-spiked simulant solution with a small mass of MST. The volume of simulant to MST (8.5 L to 0.2 g of MST solids) was designed to mimic the maximum phase ratio that occurs between the multiple contacts of MST and waste solution and washing of the accumulated solids cycle of ARP. This work provides the following results. (1) After a contact time of {approx}2 weeks, we measured the following actinide loadings on the MST (average of solution and solids data), Pu: 2.79 {+-} 0.197 wt %, U: 14.0 {+-} 1.04 wt %, and Np: 0.839 {+-} 0.0178 wt %. (2) The plutonium and uranium loadings reported above are considerably higher than previously reported values. The higher loading result from the very high phase ratio and the high initial mass concentrations of uranium and plutonium. A separate upcoming document details the predicted values for this system versus the results. (3) The strontium DF values measured in these tests proved much lower than those reported previously with simulants having the same bulk chemical composition. The low strontium DF values reflect the very low initial mass concentration of strontium in this simulant (&lt;100 {micro}g/L) compared to that in previous testing (&gt; 600 {micro}g/L).
Date: November 15, 2005
Creator: Peters, T
Partner: UNT Libraries Government Documents Department

Fate of Uranium during Sodium Aluminosilicate Formation under Waste Tank Conditions

Description: Experiments have been conducted to examine the fate of uranium during the formation of sodium aluminosilicate (NAS) when wastes containing high aluminate concentrations are mixed with wastes of high silicate concentration. Testing was conducted at varying degrees of uranium saturation. Testing examined typical tank conditions, e.g., stagnant, slightly elevated temperature (50 C). The results showed that under sub-saturated conditions uranium is not removed from solution to any large extent in both simulant testing and actual tank waste testing. There are data supporting a small removal due to sorption of uranium on sites in the NAS. Above the solubility limit the data are clear that a reduction in uranium concentration occurs with the formation of aluminosilicate. This uranium precipitation is fairly rapid and ceases when uranium reaches its solubility limit. At the solubility limit, it appears that uranium is not affected, but further testing might be warranted. Lastly, analysis of the uranium speciation in a Tank 49H set of samples showed the uranium to be soluble. Analysis of the solution composition and subsequent use of the Hobb's uranium solubility model indicated a uranium solubility limit of 32 mg/L. The measured value of uranium in the Tank 49H matched the model prediction.
Date: June 22, 2005
Creator: Wilmarth, B
Partner: UNT Libraries Government Documents Department

Perrhenate and Pertechnetate Behavior on Iron and Sulfur-Bearing Compounds.

Description: Investigations on the behavior of the radioactive element technetium frequently use a stable isotope of rhenium as an analogue. This is justified by citing the elements similar radii and major oxidation states of +7 and +4. However, at least one study [1] has shown this analogy to be imperfect. Therefore, one goal of our study is to compare the adsorption behavior of perrhenate and pertechnetate (the major forms of Re and Tc in natural waters) on a number of different mineral surfaces. Quantum mechanical calculations were performed on the adsorption of these two anions on a series of iron oxides and sulfides. With these calculations, we gain insight into any differences between the anions adsorption behavior, including geometry, adsorption energies, and electronic structure such as density of states and orbital shapes and energies at the adsorption site. Differences between interactions on terraces and step edges, the effects of co-adsorbates such as Na{sup +} or H{sup +}, and possible reduction mechanisms are also explored. The influence of water was calculated using homogeneous dielectric fluids and explicit water molecules. As a complement to the calculations, batch sorption tests are in progress involving ReO{sub 4}{sup -}/TcO{sub 4}{sup -} solution in contact with Fe metal, 10% Fe-doped hydroxyapatite, goethite, hematite, magnetite, pyrite, galena, and sphalerite.
Date: September 15, 2006
Creator: Anderson, B. E.; Becker, U.; Helean, K. B. & Ewing, R. C.
Partner: UNT Libraries Government Documents Department

Chemical Speciation of Sr, Am and Cm in high Level Waste: predictive modeling of phase partitioning during tank processing

Description: During this contract period, a number of papers were published. The papers prior to this report have been reported in earlier annual reports. This final report covers the 2005 & 2006 publications which have been published as well as the last few which have been submitted, but are still under review for acceptance for publication. The titles and abstracts of the papers are presented in section A, and the full published papers in Section B.
Date: December 20, 2006
Creator: Choppin, Gregory R.
Partner: UNT Libraries Government Documents Department

Characterization of U(VI) Sorption-Desorption Processes and Model Upscaling

Description: The objectives of the overall collaborative EMSP effort (with which this project is associated) were to characterize sorption and desorption processes of U(VI) on pristine and contaminated Hanford sediments over a range of sediment facies and materials properties and to relate such characterization both to fundamental molecular-scale understanding and field-scale models of geochemistry and mass transfer. The research was intended to provide new insights on the mechanisms of U(VI) retardation at Hanford, and to allow the development of approaches by which laboratory-developed geochemical models could be upscaled for defensible field-scale predictions of uranium transport in the environment. Within this broader context, objectives of the JHU-based project were to test hypotheses regarding the coupled roles of adsorption and impermeable-zone diffusion in controlling the fate and transport of U(VI) species under conditions of comparatively short-term exposure. In particular, this work tested the following hypotheses: (1) the primary adsorption processes in the Hanford sediment over the pH range of 7 to 10 are surface complexation reactions of aqueous U(VI) hydroxycarbonate and carbonate complexes with amphoteric edge sites on detrital phyllosilicates in the silt/clay size fraction; (2) macroscopic adsorption intensity (at given aqueous conditions) is a function of mineral composition and aquatic chemistry; and (3) equilibrium sorption and desorption to apply in short-term, laboratory-spiked pristine sediments; and (4) interparticle diffusion can be fully understood in terms of a model that couples molecular diffusion of uranium species in the porewater with equilibrium sorption under the relevant aqueous conditions. The primary focus of the work was on developing and applying both models and experiments to test the applicability of "local equilibrium" assumptions in the modeling interpretation of sorption retarded interparticle diffusion, as relevant to processes of U(VI) diffusion in silt/clay layers. Batch isotherm experiments were first used to confirm sorption isotherms under the intended test conditions ...
Date: October 12, 2006
Creator: Bai, Jing; Dong, Wenming & Ball, William P.
Partner: UNT Libraries Government Documents Department

Optimizing the Binding Energy of Hydrogen on Nanostructured Carbon Materials through Structure Control and Chemical Doping

Description: The DOE Hydrogen Sorption Center of Excellence (HSCoE) was formed in 2005 to develop materials for hydrogen storage systems to be used in light-duty vehicles. The HSCoE and two related centers of excellence were created as follow-on activities to the DOE Office of Energy Efficiency and Renewable Energy’s (EERE’s) Hydrogen Storage Grand Challenge Solicitation issued in FY 2003. The Hydrogen Sorption Center of Excellence (HSCoE) focuses on developing high-capacity sorbents with the goal to operate at temperatures and pressures approaching ambient and be efficiently and quickly charged in the tank with minimal energy requirements and penalties to the hydrogen fuel infrastructure. The work was directed at overcoming barriers to achieving DOE system goals and identifying pathways to meet the hydrogen storage system targets. To ensure that the development activities were performed as efficiently as possible, the HSCoE formed complementary, focused development clusters based on the following four sorption-based hydrogen storage mechanisms: 1. Physisorption on high specific surface area and nominally single element materials 2. Enhanced H2 binding in Substituted/heterogeneous materials 3. Strong and/or multiple H2 binding from coordinated but electronically unsatruated metal centers 4. Weak Chemisorption/Spillover. As a member of the team, our group at Duke studied the synthesis of various carbon-based materials, including carbon nanotubes and microporous carbon materials with controlled porosity. We worked closely with other team members to study the effect of pore size on the binding energy of hydrogen to the carbon –based materials. Our initial project focus was on the synthesis and purification of small diameter, single-walled carbon nanotubes (SWNTs) with well-controlled diameters for the study of their hydrogen storage properties as a function of diameters. We developed a chemical vapor deposition method that synthesized gram quantities of carbon nanotubes with average diameter size at less than 1 nm. However, initial tests performed at our ...
Date: February 1, 2011
Creator: Liu, Jie
Partner: UNT Libraries Government Documents Department

Sorption Behavior and Morphology of Plutonium in the Presence of Goethite at 25 and 80C

Description: In this study, we examined the sorption behavior of Pu at elevated temperatures in the presence of one relevant mineral, goethite ({alpha}-FeOOH), over a range of concentrations that span solubility-controlled to adsorption-controlled concentrations. We focused on the sorptive behavior of two common forms of Pu: aqueous Pu(IV) and intrinsic Pu(IV) nano-colloids at 25 and 80 C in a dilute pH 8 NaCl/NaHCO{sub 3} solution. The morphology of Pu sorbed to goethite was characterized using transmission electron microscopy (TEM). We examined the relative stability of PuO{sub 2} precipitates, PuO{sub 2} nano-colloids, Pu{sub 4}O{sub 7} surface precipitates, and monomeric sorbed Pu as a function of temperature and over a time scale of months.
Date: June 11, 2012
Creator: Zavarin, M.; Zhao, P.; Dai, Z.; Carroll, S. A. & Kersting, A. B.
Partner: UNT Libraries Government Documents Department

Summary of FY 2010 Iodine Capture Studies at the INL

Description: Three breakthrough runs using silver mordenite sorbents were conducted and a dynamic sorption capacity estimated based on MeI analysis from a 2" bed. However, it is now believed the data for the first 2 runs is incomplete because the contributions from elemental iodine were not included. Although the only source of iodine was MeI, elemental iodine was generated within the sorbent bed, presumably from a recombination reaction likely catalyzed by silver mordenite. On-line effluent analysis with a GC was only capable of analyzing MeI, not I2. Scrub samples drawn during Run #3, which are specific for I2, show significant levels of I2 being emitted from a partially spent Ag-mordenite bed. By combining MeI and I2 analyses, a well defined total iodine breakthrough curve can be generated for Run #3. At the conclusion of Run #3 (IONEX Ag-900 was the sorbent) the effluent level from Bed 2 was approaching 70% of the feed concentration. The leading bed (Bed 1) had an estimated average loading of 66 mg I/g sorbent, Bed 2's was 52 mg I/g. The corresponding silver utilizations (assuming formation of AgI) were about 59% and 46%, respectively. The spent sorbents are being sent to Sandia National Laboratories for confirmatory analysis of iodine and silver utilization as well as source material for waste form development.
Date: August 1, 2010
Creator: Haefner, Daryl R.; Watson, Tony L. & Jones, Michael G.
Partner: UNT Libraries Government Documents Department

Evaluation of Groundwater Impacts to Support the National Environmental Policy Act Environmental Assessment for the INL Remote-Handled Low-Level Waste Disposal Project

Description: The groundwater impacts have been analyzed for the proposed RH-LLW disposal facility. A four-step analysis approach was documented and applied. This assessment compared the predicted groundwater ingestion dose to the more restrictive of either the 25 mrem/yr all pathway dose performance objective, or the maximum contaminant limit performance objective. The results of this analysis indicate that the groundwater impacts for either proposed facility location are expected to be less than the performance objectives. The analysis was prepared to support the NEPA-EA for the top two ranking of the proposed RH-LLW sites. As such, site-specific conditions were incorporated for each set of results generated. These site-specific conditions were included to account for the transport of radionuclides through the vadose zone and through the aquifer at each site. Site-specific parameters included the thickness of vadose zone sediments and basalts, moisture characteristics of the sediments, and aquifer velocity. Sorption parameters (Kd) were assumed to be very conservative values used in Track II analysis of CERCLA sites at INL. Infiltration was also conservatively assumed to represent higher rates corresponding to disturbed soil conditions. The results of this analysis indicate that the groundwater impacts for either proposed facility location are expected to be less than the performance objectives.
Date: August 1, 2011
Creator: Schafer, Annette; Rood, Arthur S. & Sondrup, A. Jeffrey
Partner: UNT Libraries Government Documents Department

Evaluation of Groundwater Impacts to Support the National Environmental Policy Act Environmental Assessment for the INL Remote-Handled Low-Level Waste Disposal Project

Description: The groundwater impacts have been analyzed for the proposed RH-LLW disposal facility. A four-step analysis approach was documented and applied. This assessment compared the predicted groundwater ingestion dose to the more restrictive of either the 25 mrem/yr all pathway dose performance objective, or the maximum contaminant limit performance objective. The results of this analysis indicate that the groundwater impacts for either proposed facility location are expected to be less than the performance objectives. The analysis was prepared to support the NEPA-EA for the top two ranking of the proposed RH-LLW sites. As such, site-specific conditions were incorporated for each set of results generated. These site-specific conditions were included to account for the transport of radionuclides through the vadose zone and through the aquifer at each site. Site-specific parameters included the thickness of vadose zone sediments and basalts, moisture characteristics of the sediments, and aquifer velocity. Sorption parameters (Kd) were assumed to be very conservative values used in Track II analysis of CERCLA sites at INL. Infiltration was also conservatively assumed to represent higher rates corresponding to disturbed soil conditions. The results of this analysis indicate that the groundwater impacts for either proposed facility location are expected to be less than the performance objectives.
Date: December 1, 2011
Creator: Schafer, Annette; Rood, Arthur S. & Sondrup, A. Jeffrey
Partner: UNT Libraries Government Documents Department

Single Component Sorption-Desorption Test Experimental Design Approach Discussions

Description: A task was identified within the fission-product-transport work package to develop a path forward for doing testing to determine behavior of volatile fission products behavior and to engage members of the NGNP community to advise and dissent on the approach. The following document is a summary of the discussions and the specific approaches suggested for components of the testing. Included in the summary isare the minutes of the conference call that was held with INL and external interested parties to elicit comments on the approaches brought forward by the INL participants. The conclusion was that an initial non-radioactive, single component test will be useful to establish the limits of currently available chemical detection methods, and to evaluated source-dispersion uniformity. In parallel, development of a real-time low-concentration monitoring method is believed to be useful in detecting rapid dispersion as well as desorption phenomena. Ultimately, the test cycle is expected to progress to the use of radio-traced species, simply because this method will allow the lowest possible detection limits. The consensus of the conference call was that there is no need for an in-core test because the duct and heat exchanger surfaces that will be the sorption target will be outside the main neutron flux and will not be affected by irradiation. Participants in the discussion and contributors to the INL approach were Jeffrey Berg, Pattrick Calderoni, Gary Groenewold, Paul Humrickhouse, Brad Merrill, and Phil Winston. Participants from outside the INL included David Hanson of General Atomics, Todd Allen, Tyler Gerczak, and Izabela Szlufarska of the University of Wisconsin, Gary Was, of the University of Michigan, Sudarshan Loyalka and Tushar Ghosh of the University of Missouri, and Robert Morris of Oak Ridge National Laboratory.
Date: September 1, 2011
Creator: WInston, Phil
Partner: UNT Libraries Government Documents Department