bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogeochemical Investigation of Groundwater in the Tono Area, Japan
Authors: Iwatsuki T. , Sato K. , Seo T. , Hama K. 
Published: April 2011

AbstractMeasurements of chemical compositions of groundwaters, carbon isotope analysis of dissolved inorganic carbon and batch experiments on water-rock interaction have been carried out in order to evaluate the chemical evolution of groundwater in the sedimentary rocks of the Tono area, Japan. The activities of Na and Ca ions in the groundwater plotted along the boundary between Na- and Ca-montmorillonite stability fields on a diagram of 2pH+log[Ca2+] vs. pH+log[Na+], which indicates that the two mineral phases are in equilibrium. Groundwater samples, rich in Ca ions (14.8 ppm Ca ions and 16.3 ppm Na ions), were collected from the shallow zone of the Tono area, and were reacted with the sedimentary rocks in the batch experiments. The experiments have revealed that ion exchange occurs between Na ions in the rock samples and Ca ions in the groundwater samples, and the final solutions became rich in Na ions (1.2 ppm Ca ions and 35.2 ppm Na ions). The results of the batch experiments are in agreement with the variation of Na and Ca concentrations in the groundwater in the sedimentary rocks. The carbon isotope data showed that the fraction of HCO3 derived from the dissolution of calcite increases from 25% to 75% of the total HCO3 content with increasing depth. The molality of Na ions in the groundwater was measured to be twice that of HCO3 ions derived from calcite, which supports the Na and Ca ion exchange in the groundwater. The results suggest that the chemical evolution of the groundwater is characterized by the variation in Na, Ca and HCO3 concentrations, and that ion exchange and dissolution of calcite are dominant reactions in the evolution of groundwater in the Tono area.
Application of a Selective Phase Extraction Procedure to Samples from the Adamello Contact Aureole (Italy)
Authors: Payne T. E. , Lumpkin G. R. , McGlinn P. J. , Hart K. P. 
Published: April 2011

AbstractHydrothermal veins, rich in Ti, Zr, rare earth elements (REE’s), and actinides, occur in the pure dolomitic marbles of the Adamello contact metamorphic aureole. A selective phase extraction using 9M HC1 was applied to samples from within and near these veins to chemically separate acid-soluble phases from residual phases, and to study the associations of U, Th, and REE’s with these phases. The samples were from the phlogopite, titanian clinohumite, and forsterite vein zones, and from the country rock. The effects of the extraction were studied by SEM/EDS and by chemical analysis. Isotopes of U and Th were analysed by alpha-spectrometry.The chemical data and SEM/EDS results indicated that dolomite, calcite, apatite, and much of the pyrrhotite were dissolved by the 9M HC1, whereas spinel, phlogopite, titanite, chal copy rite, and zirconolite were among the acid-resistant phases. In all vein samples, the REE-patterns of acid-soluble phases were consistent with the dissolution of REE-rich apatite. In samples from the phlogopite zone, the majority of U, Th, and REE’s were in residual phases, and the REE pattern of the residue was similar to that of REE-rich titanite. In the titanian clinohumite zone, a substantial proportion of these elements were in acid-soluble phases, and the REE pattern of the residual phases resembled that of zirconolite. Clinohumite was partially dissolved by the HC1 treatment. The sample from the forsterite zone contained substantial amounts of REE's in acid-soluble phases, whereas Th and U were mostly in residual phases. The dolomite (country rock) samples contained small amounts of an acid-resistant, uranium-rich phase which, while only comprising about 0.2% of the mass, accounted for 40–60% of the uranium present.
Extraction of Lanthanide(III) and Uranyl(VI) from Nitric Acid Solution by Malonamides
Authors: Nakamura Takashi , Matsuda Yuki , Miyake Chie 
Published: April 2011

AbstractThe extractive properties of two malonamide extractants, DMDBO3NPDA and DMDBMA were investigated for the extraction of lanthanide(III) and uranyl(VI) ions in benzene-nitric acid systems. It was found that DMDBO3NPDA has a higher extractive capacity than DMDBMA. The difference in their extracting capacities is discussed, based on the enthalpy changes for the extraction reactions and IR data for complexes of metal nitrates with malonamides. In addition, the applicability of a mixed solvent of n-dodecane and some aliphatic alcohols as a diluent for DMDBO3NPDA was examined. The longer the carbon chain and the higher the concentration of the aliphatic alcohol, the more the phase compatibility improves. The distribution ratios of neodymium(III) ion increase with an increase in the carbon chain length of linear aliphatic alcohol and with a decrease in its concentration.
Diffusion Rate of Na+ and Cs+ in Hydrous Titanium(iv) Oxide
Authors: Kasuga Fuminori , Yamazaki Hiromichi , Inoue Yasushi 
Published: April 2011

AbstractThe diffusion rates of Na+ and Cs+ in two types of hydrous titanium(IV) oxide, precipitated at pH 6 (exchanger A) and pH 13 (exchanger B), were determined radiochemically. The rate of Cs+ in exchanger A is faster than that of Na+; diffusion coefficients are 4.9xl0-11 and 1.9xl0-11 m2 s-1 for Cs+ and Na+, respectively (pH 12, 5.0 °C). The activation energy for Cs+ diffusion is 21 kJ mol-1 and slightly smaller than that for Na+ diffusion, 29 kJ mol-1. The rates of these ions in exchanger B are much slower than those in exchanger A, and can be explained by assuming the existence of two kinds of independently diffusing ions (fast and slow species) in the exchanger. The diffusion coefficients are of the order of 10-12 and 10-13 m2 s-1 for the fast and the slow species, respectively. The activation energies are 48–60 kJ mol-1 for Na+ diffusion and 32–33 kJ mol-1 for Cs+ diffusion (pH 12). The marked difference in kinetics between two exchangers was interpreted in terms of the difference in the acid-base property and in the microstructure of the matrix.
Study of Processing Hllw by Super High Temperature Method. Part II*. Reducing Reactions and Formation of Complex Oxides in the Simplified Hllw
Authors: Uno Masayosi , Kadotani Youji , Miyake Chie , Horie Misato 
Published: April 2011

AbstractThe reducing reactions of platinum metal oxides and the formation of the complex oxides were studied to estimate the process at high temperatures. Heat treatment of Re207 with TiN causes reduction up to the sublimation point of Re207 and exhibits the highest value of the recovery among the reducing agents used in the present study. Reducing reactions of the platinum metal oxides with the reducing agents lower the melting temperature. The simplified complex oxides contain the complex oxides of the representative elements of FP and the metallic elements of the reducing agents, which contribute to a decrease of melting temperature, neodymium zirconium oxides and neodymium barium oxide which may transform to the other phases during heating. Uranium may dissolve in the phases in which uranium is identified by EPMA but cannot detected by X-ray diffraction.
Behaviour of Iodine-129 in Rice Paddy Fields
Authors: Uchida Shigeo , Muramatsu Yasuyuki 
Published: April 2011

AbstractTransfer factors of iodine from soil to rice were obtained by laboratory experiments using125I tracer. Two typical soil types in Japan, Andosol and Gray lowland soil, were used. The transfer factor (TF) is defined as ’concentration of the nuclide in a plant organ at harvest’ divided by ’concentration of the nuclide in dry soil’. The TFs for brown (hulled) rice were 0.006 for Andosol and 0.002 for Gray lowland soil. The TFs for different organs of rice plants decreased in the order of blade > stem > rachis > unhulled rice >> brown rice.The concentration of iodine in soil solution under flooded conditions varied with time during cultivation. The iodine concentration in rice plants seemed to be influenced by the soil solution.The effect of removal of 1–129 from paddy fields by harvesting rice plants was also modelled. Even assuming continuous deposition of 1–129 onto the field, annual harvesting of the blades and stems of rice plants could effectively reduce the amount of the nuclide in the root zone.
Experimental Determination of Chlorite Dissolution Rates
Authors: Rochelle Christopher A. , Bateman Keith , MacGregor Robert , Pearce Jonathan M. , Savage David , Wetton Paul D. 
Published: April 2011

AbstractCurrent concepts of the geological disposal of low- and intermediate-level radioactive wastes in the UK envisage the construction of a mined facility (incorporating cementitious engineered barriers) in chlorite-bearing rocks. To model accurately the fluid-rock reactions within the ‘disturbed zone’ surrounding a repository requires functions that describe mineral dissolution kinetics under pH conditions that vary from near neutral to highly alkaline.Therefore, an experimental study to determine the dissolution rates of Fe-rich chlorite has been undertaken as part of the Nirex Safety Assessment Research Programme. Four experiments have been carried out at 25 °C and four at 70 °C, both sets using a range of NaCl/NaOH solutions of differing pH (of nominal pH 9.0,10.3, 11.6 and 13.0 [at 25 °C]).Dissolution rates have been calculated and were found to increase with increasing pH and temperature. However, increased pH resulted in non-stoichiometric dissolution possibly due to preferential dissolution of part of the chlorite structure relative to another, or reprecipitation of some elements as thin hydroxide or oxyhydroxide surface coatings on the chlorite.These results also show that chlorite dissolution is appreciably slower than that of albite and quartz at both 25 and 70 °C, but slightly faster than that of muscovite at 70 °C.
Coupled Chemical and Diffusion Model for Compacted Bentonite
Authors: Olin M. , Lehikoinen J. , Muurinen A. 
Published: April 2011

AbstractA chemical equilibrium model has been developed for ion-exchange and to a limited extent for other reactions, such as precipitation or dissolution of calcite or gypsum, in compacted bentonite water systems. The model was successfully applied to some bentonite experiments, especially as far as monovalent ions were concerned. The fitted log-binding constants for the exchange of sodium for potassium, magnesium, and calcium were 0.27, 1.50, and 2.10, respectively.
In addition, a coupled chemical and diffusion model has been developed to take account of diffusion in pore water, surface diffusion and ion-exchange. The model was applied to the same experiments as the chemical equilibrium model, and its validation was found pardy successful. The above values for binding constants were used also in the coupled model. The apparent (both for anions and cations) and surface diffusion (only for cations) constants yielding the best agreement between calculated and experimental data were 3.0×10-11 m2/s and 6.0×10-12m2/s, respectively. These values are questionable, however, as experimental results good enough for fitting are currently not available.
Estimation of Effective Diffusivity in Compacted Ben Tonite
Authors: Kato H. , Muroi M. , Yamada N. , Ishida H. , Sato H. 
Published: April 2011

AbstractEffective diffusivities of radioactive nuclides in compacted bentonite were calculated theoretically by using an electric double layer theory. Comparison between calculated diffusivities and measured ones show good agreements.The effective diffusivity is dominated by pore structure and pore diffusivity Dp. The pore structure can be characterized by effective porosity ε eff, constrictivity δ, and tortuosity Γ. The δ was assumed to be unity. The ε eff and the Γ were determined experimentally. The Dp was estimated by means of the electric double layer theory. In the estimation, smectite interlayer was assumed the space between parallel plane sheets of smectite crystal lattice.Diffusion experiments were carried out by using Cs+ for monovalent cation, C1- and Tc04- for monovalent anion, and tritiated water for neutral molecule. The measured and calculated effective diffusivities in different densities showed the same tendency of cation > neutral > anion. The dry density of bentonite became higher, the discrepancy between the estimated and the measured diffusivities became larger. The calculation was limited by the applicability of the electric double layer theory in the near surface region of smectite.
Radiation Resistance of the Natural Microbial Population in Buffer Materials
Authors: Stroes-Gascoyne S. , Lucht L. M. , Borsa J. , Delaney T. L. , Haveman S. A. , Hamon C. J. 
Published: April 2011

AbstractThe radiation sensitivity of naturally occurring microorganisms in buffer materials vas investigated as veil as the sensitivity ofBacillus subtilisspores andAcinetobacter radioresistensin a buffer matrix. The D10values obtained in our radiation experiments varied from 0.34 to 1.68 kGy and it vas calculated that the surface of a nuclear fuel vaste container vould be sterilized in 9 to 33 d after emplacement, depending on the type of container, and the initial bioburden. This suggests that formation of biofilms and microbially influenced corrosion vould not be of concern for some time after emplacement. The results also indicated that sterilization throughout a 25 cm thick buffer layer is unlikely and that repopulation of the container surface after some time is a possibility, depending on the mobility of microbes in compacted buffer material.
Numerical Relationship between Surface Deformation and a Change of Groundwater Table Before and after an Earthquake
Authors: AKAO Yoshihiko 
Published: April 2011

AbstractThe purpose of this study is to estimate the effect of earthquakes upon a groundwater flow around a repositories for high-level radioactive wastes. Estimation of a groundwater flow change before and after an earthquake or a volcanic eruption is one of the issues for a long-term safety assessment of the repositories. However, almost any systematic investigation about the causality between a groundwater flow change and an earthquake or an eruption was not found, and as well no estimation formula has been published. We succeeded to obtain a primitive relationship between a groundwater change and an earthquake in this study.Our study consists of three stages. First, several survey reports which describe field observation results of groundwater anomalies caused by earthquakes or eruptions have been collected. The necessary data have been read from the literature and systematically arranged. Second, source mechanisms of the corresponding earthquakes were inspected and static displacements at the well positions were calculated by the dislocation theory in the seismology. Third, parametric studies among the parameters of groundwater anomalies and earthquakes were carried out to find a numerical relationship between a couple of them. Then, a preliminary relationship between water table change in a well and static displacement at the well position was found.We can conclude that temporary change of water table seems to depend on the norm of displacement vector. In this relationship, the maximum value of water table change would be approximately one hundred times of the displacement.
Near-Field Transport of 129I from a Point Source in an In-Room Disposal Vault
Authors: Kolář Miroslav , Leneveu Dennis M. , Johnson Lawrence H. 
Published: April 2011

AbstractA very small number of disposal containers of heat generating nuclear waste may have initial manufacturing defects that would lead to pin-hole type failures at the time of or shortly after emplacement. For sufficiently long-lived containers, only the the initial defects need be considered in modelling of release rates from the disposal vault. Two approaches to modelling of near-field mass transport from a single point source within a disposal room have been compared: the finite-element code MOTIF (A Model Of Transport In Fractured/porous media) and a boundary integral method (BIM). These two approaches were found to give identical results for a simplified model of the disposal room without groundwater flow. MOTIF has been then used to study the effects of groundwater flow on the mass transport out of the emplacement room.
Examination and Testing of an Active Glass Sample Produced by Cogema
Authors: Cheron P. , Chevalier Ph. , Do Quang R. , Tanguy G. , Sourrouille M. , Woignier S. , Senoo M. , Banba T. , Kuramoto K. , Yamaguchi T. , Shimizu K. , Fillet C. , Jacquet-Francillon N. , Godard J. , Dussossoy J. L. , Pacaud F. , Charbonnel J. G. 
Published: April 2011

AbstractThis paper presents the results of analyses and measurements performed on an active glass sample taken from the French vitrification facility R7.
Corrosion Behavior of Spent MTR Fuel Elements in a Drowned Salt Mine Repository
Authors: Brodda Bert-G. , Fachinger J. 
Published: April 2011

AbstractSpent MTR fuel from German Material Test Reactors will not be reprocessed, but stored in a final salt repository in the deep geologic underground. Fuel elements will be placed in POLLUX containers, which are assumed to resist the corrosive attack of an accidentally formed concentrated salt brine for about 500 years. After a container failure the brine would contact the fuel element, corrode the aluminum plating and possibly leach radionuclides from the fuel.A source term for the calculation of radionuclide mobilization results from the investigation of the behavior of MTR fuel in this scenario, which has to be considered for the long- term safety analysis of a deep mined rock salt repository.Experiments with the different plating materials show that the considered aluminum alloys will not resist the corrosive attack of a brine solution, especially in the presence of iron, under the conditions in a drowned salt mine repository. Although differences in the corrosion rates of about two orders of magnitude were observed when applying different parameter sets, the deterioration must be considered to be almost instantaneous in geological terms.Radionuclides are mobilized from irradiated MTR fuel, when the “meat” of the fuel element becomes accessible to the brine solution. It seems, however, that the radionuclides are effectively trapped by the aluminum hydroxide formed, as the activity concentrations in the brine solution soon reach a constant level with the progressing corrosion of the cladding aluminum. In the presence of iron a more significant initial release was observed, but also in this case an equilibrium activity seems to be reached as a consequence of radionuclide trapping.
The Assessment of the Long-Term Evolution of the Spent Nuclear Fuel Matrix by Kinetic, Thermodynamic and Spectroscopic Studies of Uranium Minerals.
Authors: Bruno Jordi , Casas I. , Cera E , Ewing R. C. , Finch R. J. , Werme L. O. 
Published: April 2011

AbstractThe long term behaviour of spent nuclear fuel is discussed in the light of recent thermodynamic and kinetic data on mineralogical analogues related to the key phases in the oxidative alteration of uraninite. The implications for the safety assessment of a repository of the established oxidative alteration sequence of the spent fuel matrix are illustrated with Pagoda calculations. The application to the kinetic and thermodynamic data to source term calculations indicates that the appearance and duration of the U(VI) oxyhydroxide transient is critical for the stability of the fuel matrix.
Prediction of Unknown Uranyl Oxide Hydrate Structure Types: Comparison of Calculated and Measured XRD Powder Patterns
Authors: Finch R. J. , Hawthorne F. C. , Ewing R. C. 
Published: April 2011

AbstractThe accurate identification of uranium-bearing corrosion products from spent fuel leaching studies is often difficult because the XRD powder patterns for many U(VI) phases are closely similar. Standard pattern-matching techniques commonly used for phase identification (e.g., JCPDS) make confident phase identification difficult and can oversimplify complex mixtures of UOHs. Refinement methods that fit the full XRD powder pattern, such as Rietveld, may be the only methods for accurate UOH identification, especially for data from sample mixtures. Rietveld refinement of XRD powder data for uranium oxides can be accomplished for phases whose structures are well defined. Unfortunately, many of the uranyl oxide hydrates are still ill-defined, both structurally and compositionally. The uranyl oxide hydrates have large unit cells and relatively low symmetries, as well as close structural similarities, all of which complicates the simultaneous refinement of mixed UOH phases. Modeling peak shape profiles can also hamper refinements of mixed-UOH samples due to extreme peak overlap. Because of these difficulties, Rietveld structuredeterminationfor UOHs from sample mixtures remains intractable, although structure determination may be possible for fine-grained, single-phase samples. Nonetheless, Rietveld refinement is the most promising method for accurately identifying the component phases in a mixture, but the unknown UOH structures must be determined before this technique can be applied successfully.
Impact of Thermal Loading on Waste Package Material Performance
Authors: Stahl D. , McCoy J. K. , McCright R. D. 
Published: April 2011

AbstractThis report focuses on the prediction of materials performance for the carbon steel corrosion-allowance container as a function of thermal loading for the potential repository at Yucca Mountain. Low, intermediate and high thermal loads were evaluated as to their performance given assumptions regarding the temperature and humidity changes with time and the resultant depth of corrosion penetration. The reference case involved a kinetic relation for corrosion that was utilized in a sensitivity analysis to examine the impacts of time exponent, pitting, and microbiologically-influenced corrosion. As a result of this study, the high thermal load appears to offer the best corrosion performance. However, other factors must be considered in making the final thermal loading decision.
Stochastic Modeling of the Influence of Environment on Pitting Corrosion Damage of Radioactive-Waste Containers
Authors: Henshall Gregory A. 
Published: April 2011

AbstractA physically-based, phenomenological stochastic model for pit initiation and growth is presented as a potential tool for predicting the degradation of high-level radioactive-waste containers by aqueous pitting corrosion. Included in the model are simple phenomenological equations describing the dependence of the controlling stochastic parameters on the applied (or corrosion) potential, chloride ion concentration, and absolute temperature. Results from this model are presented that demonstrate its ability to simulate several important environmental effects on pitting.
Durability of High-Level Waste Glass in Flowing Groundwater Under Gamma-Irradiation
Authors: Kamizono Hiroshi , Hashimoto Masa-Aki , Tamura Yukito , Sagawa Tamio , Matsumoto Sei-Ichiro 
Published: April 2011

AbstractDurability of simulated high-level waste glass in continuously-flowing J-13 tuff groundwater has been examined at 90°C under gamma-irradiation. The results obtained are compared with those without gamma-irradiation. The effects of groundwater radiolysis on the glass durability are discussed based on the Eh-pH excursion obtained in the present system. It is found that the groundwater tends to be reduced under gamma-irradiat ion, however, this may not influence the solubility of multivalent cations leached from the glass.