bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancement of Zirconolite Dissolution Due to Water Radiolysis
Authors: Toulhoat Nelly , Toulhoat Nelly , Moncoffre Nathalie , Toulhoat Pierre , Jegou Christophe , Corbel Catherine , Bardez Isabelle , Leturcq Gilles 
Published: October 2011

AbstractZirconolite is a candidate host material for conditioning minor tri- and tetra-valent actinides arising from enhanced nuclear spent fuel reprocessing and partitioning, in the case of disposal of the nuclear waste. Its chemical durability has been studied here under charged particle-induced radiolysis (He2+ and proton external beams) to identify the possible effects of water radiolysis on the dissolution rates in pure water and to describe the alteration mechanisms. Two experimental geometries have been used in order to evaluate the influence of the following parameters: solid irradiation, water radiolysis. In the first geometry the beam gets through the sample before stopping at the surface/water interface. In the second one the beam stops before the surface/water interface. Results on the elemental releases due to the enhanced dissolution of the zirconolite surface during charged particle-induced irradiation of water are presented. Under radiolysis, an increase of one order of magnitude is observed in the Ti, Zr and Nd elemental releases. No difference in the total elemental releases can be noticed when the solid is also irradiated.
Characterisation of Plasma Vitrified Simulant Plutonium Contaminated Material Waste
Authors: Hyatt Neil Christian , Morgan Suzy , Stennett Martin C. , Scales Charlie R. , Deegan David 
Published: October 2011

AbstractThe potential of plasma vitrification for the treatment of a simulant Plutonium Contaminated Material (PCM) was investigated. It was demonstrated that the PUO2 simulant, CeO2, could be vitrified in the amorphous calcium iron aluminosilicate component of the product slag with simultaneous destruction of the organic and polymer waste fractions. Product Consistency Tests conducted at 90ºC in deionised water and buffered pH 11 solution show the PCM slag product to be durable with respect to release of Ce.
Simulation of Self-Irradiation of High-Sodium Content Nuclear Waste Glasses
Authors: Ojovan Michael I. , Batyukhnova Olga G. , Ojovan Michael I. , Lee William E. 
Published: October 2011

AbstractAlkali-borosilicate glasses are widely used in nuclear industry as a matrix for immobilisation of hazardous radioactive wastes. Durability or corrosion resistance of these glasses is one of key parameters in waste storage and disposal safety. It is influenced by many factors such as composition of glass and surrounding media, temperature, time and so on. As these glasses contain radioactive elements most of their properties including corrosion resistance are also impacted by self-irradiation.The effect of external gamma-irradiation on the short-term (up to 27 days) dissolution of waste borosilicate glasses at moderate temperatures (30¢X to 60¢XC) was studied. The glasses studied were Magnox Waste glass used for immobilisation of HLW in UK, and K-26 glass used in Russia for ILW immobilisation. Glass samples were irradiated under ×-source (Co-60) up to doses 1 and 11 MGy. Normalised rates of elemental release and activation energy of release were measured for Na, Li, Ca, Mg, B, Si and Mo before and after irradiation. Irradiation up to 1 MGy results in increase of leaching rate of almost all elements from both MW and K-26 with the exception of Na release from MW glass. Further irradiation up to a dose of 11 MGy leads to the decrease of elemental release rates to nearly initial value. Another effect of irradiation is increase of activation energies of elemental release.
Porous Alumina Silicate Matrix Gubka for Solidification of 137Cs Strip Product
Authors: Aloy Albert , Strelnikov Alexander , Essimantovskiy Vyacheslav 
Published: October 2011

AbstractSeparated liquid highâlevel radioactive waste (HLW) fractions, in particular, about 100 l of 137Cs strip product with activity up to ∼ 100 Ci/l (3.7 TBq/l) have been produced during the development and testing of partitioning technology and temporary stored at “V.G. Khlopin Radium Institute” (SaintâPetersburg, Russia). The benchâscale experimental unit designed for operation in the hot cell was developed for 137Cs strip product solidification with using of alumina silicate porous inorganic material (PIM) called Gubka.Conditions of saturation, drying and calcinations of the salts into Gubka pores were optimized and the operations under remote control regime were executed during tests with using of simulated strip product doped with 137Cs. The volume reduction coefficients were equal by a factor of 3.2â3.9 and 137Cs discharge into offâgas system was not detected. 137Cs leach rates from Gubka blocks after calcination at 800 Â°C were 1.0â1.5*10-3 g/m2*day.
Effects of Compaction and Temperature on Sorption and Diffusion of Cs and HTO in Compacted Bentonite Saturated with Saline Water
Authors: Suzuki Satoru , Haginuma Masashi , Suzuki Kazunori 
Published: October 2011

AbstractThe sorption and diffusion of Cs and HTO in compacted bentonite was investigated at temperatures from 30 to 60°C. The apparent (Da) and effective (De) diffusion coefficients were determined by in-diffusion and through-diffusion experiments with a constant boundary concentration maintained. The temperature dependence of De and Da obeyed an Arrhenius-type equation, allowing determination of the activation energy for diffusion of Cs and HTO. The De value of Cs was three times the De of HTO, which is considered to be a result of surface-excess diffusion. Cs may be concentrated near the surface of the negatively charged clay, thus giving a large diffusive flux. The activation energies for Cs diffusion were 21.4×2.8 kJ/mol and 37.3×1.5 kJ/mol as determined based on De and Da, respectively. This difference was due to the temperature dependence of the distribution coefficient Kd of Cs.
Modeling Studies on Microbial Effects on Groundwater Chemistry
Authors: Tochigi Yoshikatsu , Yoshikawa Hideki , Yui Mikazu 
Published: October 2011

AbstractThe overall goal of this project is to develop a model to predict microbial effects on the performance of a high-level radioactive waste (HLW) repository. As a first step, the effects of microbes on groundwater chemistry have been evaluated with the numerical code 'MINT', using data collected from the borehole HDB-6 in the Horonobe underground research laboratory (URL) in Japan. The MINT code models biochemistry and geochemical equilibrium, with consideration of transport of solute and microbial activity. The MINT code simulates the activities of 6 major groups of microbes, classified by their metabolism as 'aerobic', 'denitrifying', 'manganese reducing', 'iron reducing', 'sulfate reducing' and 'methanogenic'. The specific activity of each of these groups will depend on the redox potential (Eh) of the groundwater.Sensitivity analyses were performed to investigate the consequences of changes in groundwater composition on the effects of microbial activity. This indicates that the activities of Sulfate Reducing Bacteria (SRB) and methanogens are relatively high. The concentration of dissolved methane produced by such microbial activity is seen to be influenced by sulfate concentration. Based on the observed data from Horonobe URL, the concentration in oxygen is relatively high and the activity of denitrifying bacteria is the highest of the major 6 groups of microbes. This can, however, be attributable to chemical / microbial contamination of the groundwater during sampling. The modeling results indicate that the concentration of dissolved oxygen and nitrate ion should be quickly reduced by microbial metabolism, reducing the redox potential to a level low enough for active methanogenesis to commence. Such assessment can be important to evaluate the reliability of sampling and measurement techniques for sensitive geochemical parameters in general - and microbiology in particular.
Permeability Change of Crystalline Silicate Mineral-Packed Bed Column by Highly Alkaline Plume
Authors: Usui Hideo , Niibori Yuichi , Tochiyama Osamu , Mimura Hitoshi 
Published: October 2011

AbstractFor the construction of the geological disposal system, the use of the cementitious material may affect the permeability change of the natural barrier around the repository. In practice, the construction requires a large amount of cement to maintain the mechanical stability of the repository system, particularly in Japan. Since such material alters the pH of ground water to highly alkaline region, also the permeability change of natural barrier is one of the notable factors for the performance assessments of geological disposal system.In the high pH region, the solubility of silicic acid is very high compared to that in the natural pH (around 8). Therefore, the highly alkaline groundwater would dissolve and alter a part of rock surface. Usui et al. (2005) reported that the change of the pore structure due to the chemical reaction is the key factor to consider the change of the permeability. Moreover, such a change of the pore structure was considered as the result of the spatial heterogeneity of chemical composition. Since such spatial heterogeneity exists also in the sedimentary rocks consisted of crystalline minerals such as quartz and feldspar, we need to examine natural rock, in order to obtain more reliable understanding about the change of permeability induced by the highly alkaline groundwater (plume).In this study, as crystalline mineral, silica sand was packed in the column, and the effect of dissolution induced by the highly alkaline plume on the permeability-change was examined. The silica sand particles mainly consist of SiO2 partially including Al2O3, CaO, Na2O3, and K2O. The volumetric flow rate and the pressure difference between the inlet and outlet of the column were measured, and the permeability was calculated. At the same time, the concentration of elements in the fluid was measured by the ICP-AES.The experimental result showed that permeability decreased gradually, although the silica sand was continuously dissolved in the column. The behavior of the permeability is considered to be the result from the rearrangement of the particles. In the column test using the silica sand as packed mineral, the flow-path seems to be clogged by the rearrangement of the particles rather than the increase of the pore between the particles.
Determination of Granites' Mineral Specific Porosities by PMMA Method and FESEM/EDAX
Authors: Siitari-Kauppi Marja , Penttinen L. , Siitari-Kauppi M. , Alanso U. , Garcia-Gutierrez M. , Missana T. , Patelli Alessandro 
Published: October 2011

AbstractOver extended periods, long-lived radionuclides (RN) or activation products within geologic disposal sites may be released from the fuel and migrate to the geo/biosphere. In the bedrock, contaminants will be transported along fractures by advection and retarded by sorption on mineral surfaces and by molecular diffusion into stagnant pore water in the matrix along a connected system of pores and micro-fissures.The objective of this paper was to determine the connective porosity and mineral-specific porosities for three granite samples by 14C methylmethacrylate (14C-PMMA) autoradiography. Scanning electron microscopy and energy-dispersive X-ray analyses (FESEM/EDAX) were performed in order to study the pore apertures of porous regions in greater detail and to identify the corresponding minerals. Finally, the porosity results were used to evaluate the diffusion coefficients of RNs from previous experiments which determined apparent diffusion coefficients for the main minerals in three granite samples by the Rutherford Backscattering technique.The total porosity of the Grimsel granite (0.75%) was significantly higher than the porosities of the El Berrocal and Los Ratones granites (0.3%). The porosities of the Grimsel granite feldspars were two to three times higher than the porosities of the El Berrocal and Los Ratones granites' feldspars. However, there was no significant difference between the porosities of the dark minerals. A clear difference was found between the various quartz grains. Quartz crystals were nonporous in the El Berrocal and Los Ratones granites when measured by the PMMA method, but the quartz crystals in the Grimsel granite showed 0.5% intra granular porosity. The apparent diffusion coefficients calculated for uranium diffusion within Grimsel granite on different minerals were very similar (210-13 ± 0.5 m2/s), but differences within both Spanish granites were found from one mineral to another (9 ± 110-14 m2/s in feldspars and 4.5 ± 0.510-14 m2/s in quartz) - always presenting lower diffusion values than in the Grimsel granite.
Aqueous Dissolution of Silver Iodide and Associated Iodine Release under Reducing Conditions with Sulfide<B>
Authors: Inagaki Yaohiro , Imamura Toshitaka , Idemitsu Kazuya , Arima Tatsumi , Kato Osamu , Asano Hidekazu , Nishimura Tsutomu 
Published: October 2011

AbstractAqueous dissolution tests of AgI were performed in Na2S solutions in order to evaluate, empirically, dissolution of AgI to release iodine under reducing conditions with sulfide. The results indicated that AgI dissolves to release iodine being controlled by mainly precipitation of Ag2S. However, the dissolution of AgI can be depressed to proceed, and the thermodynamic equilibrium cannot be attained easily. Solid phase analysis for the reacted AgI suggested that a thin layer of solid silver forming at AgI surface may evolve to be protective against transportation of reactant species, which can lead to the depression in the dissolution of AgI.
Chemistry of Water Collected from an Unventilated Drift, Yucca Mountain, Nevada
Authors: Marshall Brian D , Oliver Thomas A. , Peterman Zell E. 
Published: October 2011

AbstractWater samples (referred to as puddle water samples) were collected from the surfaces of a conveyor belt and plastic sheeting in the unventilated portion of the Enhanced Characterization of the Repository Block (ECRB) Cross Drift in 2003 and 2005 at Yucca Mountain, Nevada. The chemistry of these puddle water samples is very different than that of pore water samples from borehole cores in the same region of the Cross Drift or than seepage water samples collected from the Exploratory Studies Facility tunnel in 2005. The origin of the puddle water is condensation on surfaces of introduced materials and its chemistry is dominated by components of the introduced materials. Large CO2 concentrations may be indicative of localized chemical conditions induced by biologic activity.
Geochemistry of Natural Components in the Near-Field Environment, Yucca Mountain, Nevada
Authors: Peterman Zell E. , Oliver Thomas A. 
Published: October 2011

AbstractThe natural near-field environment in and around the emplacement drifts of the proposed nuclear waste repository at Yucca Mountain, Nevada, includes the host rock, dust, seepage, and pore water. The chemical compositions of these components have been analyzed to provide a basis for assessing possible chemical and mineralogical reactions that may occur after nuclear waste is emplaced. The rock unit hosting the proposed repository has a relatively uniform chemical composition as shown by samples with a mean coefficient of variation (CV) of 9 percent for major elements. In contrast, compositional ranges of underground dust (bulk and water-soluble fractions), pore water, and seepage water are large with mean CVs ranging from 28 to 64 percent for major constituents.
Status of the French Research on Partitioning and Transmutation
Authors: Warin Dominique 
Published: October 2011

AbstractThe global energy context pleads in favour of a sustainable development of nuclear energy since the demand for energy will likely increase, whereas resources will tend to get scarcer and the prospect of global warming will drive down the consumption of fossil fuel sources.How we deal with radioactive waste is crucial in this context. The production of nuclear energy in France has been associated, since its inception, with the optimization of radioactive waste management, including the partitioning and the recycling of recoverable energetic materials. The public's concern regarding the long-term waste management made the French Government to prepare and pass the December 1991 Law, requesting in particular the study for fifteen years of solutions for still minimizing the quantity and the hazardousness of final waste, via partitioning and transmutation.At the end of these fifteen years of research, it is considered that partitioning techniques which have been validated on real solutions are at disposal. Indeed, aqueous process for separation of minor actinides from the PUREX raffinate has been brought to a point where there is reasonable assurance that industrial deployment can be successful. A key experiment has been the kilogram scale successful trials in the CEA-Marcoule Atalante facility in 2005 and this result, together with the results obtained in the frame of the successive European projects, constitutes a considerable step forward. For transmutation, CEA has conducted programmes proving the feasibility of the elimination of minor actinides and fission products: fabrication of specific targets and fuels for transmutation tests in the HFR and Phénix reactors, neutronics and technology studies for critical reactors and ADS developments. Scenario studies have also allowed assessing the feasibility, at the level of cycle and fuel facilities, and the efficiency of transmutation in terms of the quantitative reduction of the final waste inventory depending of the reactor fleet (PWR-FR-ADS).Important results are now available concerning the possibility of significantly reducing the quantity and the radiotoxicity of long-lived waste in association with a sustainable development of nuclear energy. As France has confirmed its long-term approach to nuclear energy, the most effective implementation of P and T of minor actinides relies on the fast neutron GEN IV systems which are designed to recycle and manage their own actinides. The perspective to deploy a first series of such systems around 2040 supports the idea that progress is being made: the long-term waste would only be made up of fission products, with very low amounts of minor actinides.In this sense, the new waste management Law passed by the French Parliament on June 28, 2006, demands that P and T research continues in strong connection to GEN IV systems and ADS development and allowing to assess the industrial perspectives of such systems in 2012 and to put into operation a transmutation demo facility in 2020.
Transmutation and the Global Nuclear Energy Partnership
Authors: Bresee James 
Published: October 2011

AbstractIn the January 2006 State of the Union address, President Bush announced a new Advanced Energy Initiative, a significant part of which is the Global Nuclear Energy Initiative. Its details were described on February 6, 2006 by the U.S. Secretary of Energy. In summary, it has three parts: (1) a program to expand nuclear energy use domestically and in foreign countries to support economic growth while reducing the release of greenhouse gases such as carbon dioxide. (2) an expansion of the U.S. nuclear infrastructure that will lead to the recycling of spent fuel and a closed fuel cycle and, through transmutation, a reduction in the quantity and radiotoxicity of nuclear waste and its proliferation concerns, and (3) a partnership with other fuel cycle nations to support nuclear power in additional nations by providing small nuclear power plants and leased fuel with the provision that the resulting spent fuel would be returned by the lessee to the lessor. The final part would have the effect of stabilizing the number of fuel cycle countries with attendant non-proliferation value. Details will be given later in the paper.
ECD Management in a Middle East well with the aid of Formation Pressure While Drilling
Authors: Janjua Inamullah , Faizal Syed Abu , Al Dabyah Ali 
Published: October 2011

Abstract
One of the main challenges that today’s drilling operation faces is uncertainty in formation pressures. Excessive overbalance between the Equivalent Circulating Density (ECD) and formation pressure causes unnecessary, often detrimental formation breakdown, while underbalance drilling increases the risk of drilling kicks which can lead to catastrophic blowouts at the worst case scenario. Due to the uncertainty in formation pressures, managing the ECD becomes quite challenging and difficult. The ECD presents a significant drilling parameter particularly in wells that have a narrow window between the fracture gradient and pore-pressure gradient. Therefore, as early as possible knowledge of pore pressures, is highly sought after by the operating company.
Formation pressure while drilling (FPWD) technology has proved over the past few years to provide accurate formation pressures during drilling. Apart from the use of formation pressures to calculate fluid gradients, mobilities and identify tight zones, it has also found its usefulness in ECD management.
This paper presents a case study from an onshore horizontal well in the Middle East, which discusses the successful application of FPWD in ECD management. Due to the lack of reservoir formation pressure data, a heavier mud than necessary was used to drill the reservoir section to avoid risk of formation fluid influx. However, accurate measurements of pore pressures in real time recorded from a FPWD tool indicated lower pore pressures than expected. Consequently, based on that real time data, decision was made to significantly reduce the ECD, which resulted in improved hole cleaning, performance, increased rate of penetration, among other benefits.
Is There an Association between Earnings Management and Auditor-Provided Tax Services?
Authors: Krishnan Gopal V. , Visvanathan Gnanakumar 
Published: October 2011

ABSTRACT
The issue of whether auditor-provided nonaudit services enhance or exacerbate financial reporting quality has been intensely debated among regulators, auditors, investors, academic researchers, and the media. In 2006, the SEC approved the rules proposed by the PCAOB limiting the tax services that incumbent auditors can offer to their clients. We contribute to this debate by examining whether auditor-provided tax services mitigate earnings management. We find a negative and significant relation between earnings management (loss avoidance) and tax fee paid to the incumbent auditor. Our results are consistent with knowledge spillover, i.e., when the same audit firm provides both audit and tax services, insight learned from providing tax services can contribute to audit quality.
Approximate Calculation of Capacitance of Lines with Multilayer Medium
Authors: Milovanović Alenka , Bjekić Miroslav 
Published: October 2011

Approximate Calculation of Capacitance of Lines with Multilayer MediumIn this paper calculations of the capacitance per unit length of one or multilayer dielectric lines are presented. Special attention is given to the calculations of the capacitance per unit length of lines with rectangular cross sections, whose electrodes may be in different or the same layers of a two layer dielectric line. For the purpose of performing the above, several numerical methods are used and simple approximate expressions are proposed.
L'invention du for intérieur
Authors: Neyraut Michel 
Published: October 2011

Résumé For intérieur vient de forum, marché, place publique, tribunal. Le concept d’intériorité apparaît tardivement dans la pensée occidentale. Une étude de saint Augustin souligne les impératifs d’un langage de la prière. Ses prolongements chez Lacan. L’espace intérieur dessiné par Nicolas de Cues relance le procès des miroirs comme illustrant celui de la causalité psychique. Une application technologique récente permet à un individu de transporter les données de son code génétique.