Long-term aqueous alteration kinetics of an alpha-doped SON68 borosilicate glass

2013 ◽  
Vol 1518 ◽  
pp. 9-14 ◽  
Author(s):  
Magaly Tribet ◽  
Séverine Rolland ◽  
Sylvain Peuget ◽  
Magali Magnin ◽  
Véronique Broudic ◽  
...  
Keyword(s):  
Radiation Effects ◽  
Chemical Reactivity ◽  
Pure Water ◽  
High Surface ◽  
Protective Layer ◽  
Chemical Oxidation ◽  
Alpha Radiation ◽  
Sem And Tem ◽  
Static Conditions

ABSTRACTThe long-term behavior of nuclear glass subjected to alpha radiation by minor actinides must be investigated with a view to geological disposal. This study focuses on the effect of alpha radiation on the chemical reactivity of R7T7 glass with pure water, mainly on the residual alteration rate regime. A glass specimen doped with 0.85 wt% 239PuO2 (α emitter) is leached under static conditions in argon atmosphere at 90°C and at a high surface-area-to-volume ratio (S/V = 20 cm−1). The alteration rate is monitored by the release of glass alteration tracer elements (B, Na and Li). Radiation effects on the leached glass and its gel network are characterized by SEM and TEM analyses. Plutonium release is also measured by radiometry and its chemical oxidation state is assessed by measuring the pH and redox potential of the leachates. The results do not highlight any significant effect of alpha radiation on the residual alteration of this doped glass. This observation is consistent with SEM and TEM characterizations, which show that a protective layer can be formed under alpha radiation. Very low concentrations of soluble plutonium are measured in the leachate. These Pu releases are three orders of magnitude lower than the boron release, indicating strong plutonium retention.

scholarly journals Alpha dose rate and decay dose impacts on the long-term alteration of HLW nuclear glasses

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Magaly Tribet ◽  
Caroline Marques ◽  
Sarah Mougnaud ◽  
Véronique Broudic ◽  
Christophe Jegou ◽  
...  
Keyword(s):  
Dose Rate ◽  
Chemical Reactivity ◽  
Alpha Decay ◽  
Glass Block ◽  
Alpha Radiation ◽  
Wide Range ◽  
High Level ◽  
Static Conditions ◽  
Doped Glass

AbstractIn the prospect of deep geological disposal, the long-term behavior of high-level nuclear glasses has to be investigated regarding alpha radiation induced by long-life minor actinides. The present study focuses on the effects of alpha radiation on the long-term chemical reactivity of R7T7-type glasses, by separately considering the alpha dose rate and the alpha decay dose. Old SON68 glasses doped with 238/239PuO2 or 244CmO2 were studied to simulate high alpha dose rates corresponding to an early water ingress and a high level of alpha decay doses corresponding to long-term disposal conditions. A part of the 238/239Pu-doped glass block was annealed to fully recover the irradiation-induced damage accumulated since the glass was fabricated and to dissociate the effect of the alpha dose rate from that of the alpha decay dose. The glasses were then leached under static conditions at 90 °C for several years. The results showed that the residual alteration rate is not affected by the alpha dose rate over a wide range of dose rate values expected under disposal conditions: this glass remained relatively insensitive to the alpha radiolysis phenomena at the glass–water interface. However, over the duration of the experiments, the residual alteration rate of the damaged 238/239Pu-doped glass was enhanced compared to that of the annealed glass. This result is in agreement with those obtained on the 244Cm-doped glass and with reported values in the literature on simplified externally irradiated glasses, indicating that the ballistic effects of the recoil nuclei are responsible for this increase in the residual alteration rate.

Preparation, Characterization and Performance of Polyethersulfone(PES) – Polyaniline(Pani) Blended Membrane

2011 ◽  
Vol 233-235 ◽  
pp. 3018-3022 ◽  
Author(s):  
Nor Faizah Binti Razali ◽  
Abdul Wahab Mohammad ◽  
Sulaiman Al Fadul
Keyword(s):  
Conducting Polymers ◽  
Pure Water ◽  
High Surface ◽  
Water Flux ◽  
Chemical Properties ◽  
Chemical Oxidation ◽  
Environmental Stability ◽  
Hydrophilic Property ◽  
Wide Range ◽  
Blended Membrane

Polyaniline nanoparticle was synthesized via the chemical oxidation of aniline with ammonium persulphate in aqueous hydrochloric acid where the polyaniline particle size obtained was in the range of 22-53 nm. Polyaniline is one type of conducting polymers, where this polymer exhibit high electrical conductivity and have a wide range of interesting application due to its light weight, conductivity and chemical properties. Amongst the family of conducting polymers, polyaniline is unique due to ease of synthesis, environmental stability, simple doping/dedoping chemistry and relatively inexpensive cost. Polyaniline has been used to improve hydrophilic property and permeability of substrate membrane. It is used to obtain superhydrophilic surface because of their high surface energy and hydrophilic property. In this research, these nanoparticles have been used to improve hydrophilic property and permeability of polyethersulfone membrane. The blended membrane was characterized using pure water flux, Scanning Electron Microscope (SEM), and contact angle. As a result, polyaniline can distribute stably in polyaniline membrane to produce stable structure and preferable performance.

The Long-Term Corrosion and Modelling of Two Simulated Belgian Reference High-Level Waste Glasses - Part II

1989 ◽  
Vol 176 ◽  
Author(s):  
J. Patyn ◽  
P. Van Iseghem ◽  
W. Timmermans
Keyword(s):  
Pure Water ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
High Level Waste ◽  
Final State ◽  
Leach Rate ◽  
Enhanced Dissolution ◽  
High Level

ABSTRACTThe long term corrosion of two reference Belgian high-level waste glasses (SAN60 and SM58) were investigated in pure water. The corrosion was studied using powdered glass at a high surface area to volume ratio and temperatures of 90 and 120°C. The experimental data at 90°C reveal a “final” leach rate which decreases with time. At 120°C this “final” state is transient and followed by an enhanced dissolution, which was correlated with extensive surface crystallization. Modelling using the PHREEQE and GLASSOL computer codes described the initial corrosion, but was unable to account for the enhanced dissolution at 120°C.

Protective Effect of the Alteration Gel: A Key Mechanism in the Long-Term Behavior of Nuclear Waste Glass

2000 ◽  
Vol 663 ◽  
Author(s):  
S. Gin
Keyword(s):  
Diffusion Barrier ◽  
Pure Water ◽  
Barrier Properties ◽  
Residual Rate ◽  
Protective Properties ◽  
Experimental Alteration ◽  
Glass Specimen ◽  
Static Conditions ◽  
Long Term Behavior

ABSTRACTExperimental alteration results are presented in which a French SON 68 (R7T7-type) nuclear containment glass specimen was first altered under static conditions for 600 days at an S/V ratio of 5000 m−1 before transferring it to pure water. The experiment was designed to assess the diffusion barrier properties of the gel formed during the preliminary alteration phase. Contrary to predictions by kinetic models based only on chemical affinity, the renewed alteration of the specimen in pure water was very limited. Measurements at close intervals showed that the maximum alteration rate under these conditions was 7 ×10−3 g·m−2d−1, or about r0/300, whereas a pristine glass coupon in contact with pure water is altered at r0.The renewed alteration behavior is attributed to partial (5–10%) dissolution of the existing gel, resulting in a slight degradation of its protective properties. Saturation conditions, at a different level than in the preliminary phase, were reached within a few days. The saturation of the solution with respect to silicon, generally interpreted as a glass/solution (Grambow) or gel/solution (Bourcier) equilibrium, is shown to depend not only on the alteration conditions, but also on the specimen leaching history, and is thus not an inherent glass property.This experiment confirms the idea that the gel formed under saturation conditions controls the kinetics of SON 68 glass alteration by means of a diffusion barrier effect. It also raises a number of issues concerning the concept of a “residual rate” and the possible relations between the quasi steady-state Si concentrations observed in solution and the protective properties of the gel.

Relationships Between Soluble and Sediment Nutrient Losses, Land Use and Types of Soil in Agricultural Watersheds

1977 ◽  
Vol 12 (1) ◽  
pp. 121-134 ◽  
Author(s):  
G.H. Neilsen ◽  
A.F. Mackenzie
Keyword(s):  
Land Use ◽  
Inorganic Nitrogen ◽  
High Surface ◽  
Sediment Concentration ◽  
Chemical Oxidation ◽  
Nutrient Loss ◽  
Potassium Sulfate ◽  
Agricultural Watersheds ◽  
Nutrient Losses ◽  
Calcium Magnesium

Abstract Seven agricultural watersheds in southwestern Quebec and southeastern Ontario, ranging in area from 2,000 to 20,000 hectares, were monitored systematically during 1973–75 for soluble inorganic nitrogen, total soluble phosphorus, calcium, magnesium, potassium, sulfate-sulfur, chemical oxidation demand, discharge, suspended sediment concentration, sediment Kjeldahl nitrogen, Bray extractable phosphorus, and ammonium acetate extractable calcium, magnesium and potassium. For 1974–75, annual Kg/ha, loss rates were calculated for the soluble and sediment associated nutrients. Losses varied with nutrient and watershed, with volume of runoff being an important control of nutrient loss variation. Significant amounts of SO4−S in precipitation were suggested by an average watershed soluble N:P:S loss ratio of 10:1:92. Sediment nutrient losses were especially important for N and P, comprising over 40% of their total loss. The importance of spring snow-melt runoff was demonstrated by the high proportion of all nutrients lost at this time. Correlations of nutrient loss, land use and soils suggested that certain land uses resulted in increased stream nutrient losses while increased watershed area of soils with a high surface runoff potential was particularly conducive to increased soluble nutrient and sediment losses.

Atomic Layer Deposition of a Nanometer-Thick Li3PO4 Protective Layer on LiNi0.5Mn1.5O4 Films: Dream or Reality for Long-Term Cycling?

2021 ◽  
Vol 13 (13) ◽  
pp. 15761-15773
Author(s):  
Maxime Hallot ◽  
Borja Caja-Munoz ◽  
Clement Leviel ◽  
Oleg I. Lebedev ◽  
Richard Retoux ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Protective Layer ◽  
Atomic Layer ◽  
Layer Deposition

scholarly journals Novel Surfactant-Free Water Dispersion Technique of TiO2 NPs Using Focused Ultrasound System

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 427
Author(s):  
Seon Ae Hwangbo ◽  
Minjeong Kwak ◽  
Jaeseok Kim ◽  
Tae Geol Lee
Keyword(s):  
Tio2 Nanoparticles ◽  
Focused Ultrasound ◽  
Pure Water ◽  
Free Water ◽  
Dispersion Stability ◽  
Renewable Energy Resources ◽  
Water Dispersion ◽  
Dispersion State ◽  
Dispersion Technique

Titanium dioxide (TiO2) nanoparticles are used in a wide variety of products, such as renewable energy resources, cosmetics, foods, packaging materials, and inks. However, large quantities of surfactants are used to prepare waterborne TiO2 nanoparticles with long-term dispersion stability, and very few studies have investigated the development of pure water dispersion technology without the use of surfactants and synthetic auxiliaries. This study investigated the use of focused ultrasound to prepare surfactant-free waterborne TiO2 nanoparticles to determine the optimal conditions for dispersion of TiO2 nanoparticles in water. Under 395–400 kHz and 100–105 W conditions, 1 wt% TiO2 colloids were prepared. Even in the absence of a surfactant, in the water dispersion state, the nanoparticles were dispersed with a particle size distribution of ≤100 nm and did not re-agglomerate for up to 30 days, demonstrating their excellent dispersion stability.

scholarly journals Development of a Water Matrix Certified Reference Material for Volatile Organic Compounds Analysis in Water

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4370
Author(s):  
Liping Fang ◽  
Linyan Huang ◽  
Gang Yang ◽  
Yang Jiang ◽  
Haiping Liu ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Reference Material ◽  
Organic Compounds ◽  
Certified Reference Material ◽  
Pure Water ◽  
Term Stability ◽  
Long Term Stability ◽  
Water Matrix ◽  
Volatile Organic

Water matrix certified reference material (MCRM) of volatile organic compounds (VOCs) is used to provide quality assurance and quality control (QA/QC) during the analysis of VOCs in water. In this research, a water MCRM of 28 VOCs was developed using a “reconstitution” approach by adding VOCs spiking, methanol solution into pure water immediately prior to analysis. The VOCs spiking solution was prepared gravimetrically by dividing 28 VOCs into seven groups, then based on ISO Guide 35, using gas chromatography-mass spectrometry (GC-MS) to investigate the homogeneity and long-term stability. The studies of homogeneity and long-term stability indicated that the batch of VOCs spiking solution was homogeneous and stable at room temperature for at least 15 months. Moreover, the water MCRM of 28 VOCs was certified by a network of nine competent laboratories, and the certified values and expanded uncertainties of 28 VOCs ranged from 6.2 to 17 μg/L and 0.5 to 5.3 μg/L, respectively.

Tailored Mesoporous Silicas: From Confinement Effects to Catalysis

2009 ◽  
Vol 1217 ◽  
Author(s):  
A. C. Buchanan, III ◽  
Michelle K. Kidder
Keyword(s):  
Chemical Reactivity ◽  
High Surface ◽  
High Surface Area ◽  
Mesoporous Silicas ◽  
Surface Immobilization ◽  
Product Selectivity ◽  
Aryl Ether ◽  
Ether Linkage ◽  
Synthetic Methodologies ◽  
The Impact

AbstractOrdered mesoporous silicas continue to find widespread use as supports for diverse applications such as catalysis, separations, and sensors. They provide a versatile platform for these studies because of their high surface area and the ability to control pore size, topology, and surface properties over wide ranges. Furthermore, there is a diverse array of synthetic methodologies for tailoring the pore surface with organic, organometallic, and inorganic functional groups. In this paper, we will discuss two examples of tailored mesoporous silicas and the resultant impact on chemical reactivity. First, we explore the impact of pore confinement on the thermochemical reactivity of phenethyl phenyl ether (PhCH2CH2OPh, PPE), which is a model of the dominant β-aryl ether linkage present in lignin derived from woody biomass. The influence of PPE surface immobilization, grafting density, silica pore diameter, and presence of a second surface-grafted inert “spacer” molecule on the product selectivity has been examined. We will show that the product selectivity can be substantially altered compared with the inherent gas-phase selectivity. Second, we have recently initiated an investigation of mesoporous silica supported, heterobimetallic oxide materials for photocatalytic conversion of carbon dioxide. Through surface organometallic chemistry, isolated M-O-M’ species can be generated on mesoporous silicas that, upon irradiation, form metal to metal charge transfer bands capable of converting CO2 into CO. Initial results from studies of Ti(IV)-O-Sn(II) on SBA-15 will be presented.

scholarly journals Effects of radiative heat transfer on the structure of turbulent supersonic channel flow

2011 ◽  
Vol 677 ◽  
pp. 417-444 ◽  
Author(s):  
S. GHOSH ◽  
R. FRIEDRICH ◽  
M. PFITZNER ◽  
CHR. STEMMER ◽  
B. CUENOT ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Radiation ◽  
Radiative Heat Transfer ◽  
Radiation Effects ◽  
Radiative Heat ◽  
Pure Water ◽  
Molecular Transport ◽  
Working Fluid ◽  
Mean Flow ◽  
Total Energy Balance

The interaction between turbulence in a minimal supersonic channel and radiative heat transfer is studied using large-eddy simulation. The working fluid is pure water vapour with temperature-dependent specific heats and molecular transport coefficients. Its line spectra properties are represented with a statistical narrow-band correlated-k model. A grey gas model is also tested. The parallel no-slip channel walls are treated as black surfaces concerning thermal radiation and are kept at a constant temperature of 1000 K. Simulations have been performed for different optical thicknesses (based on the Planck mean absorption coefficient) and different Mach numbers. Results for the mean flow variables, Reynolds stresses and certain terms of their transport equations indicate that thermal radiation effects counteract compressibility (Mach number) effects. An analysis of the total energy balance reveals the importance of radiative heat transfer, compared to the turbulent and mean molecular heat transport.

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