Tc Behavior in the Basalt-Synthetic Groundwater System as a Function of Temperature and Initial Oxygen Content

1986 ◽  
Vol 84 ◽  
Author(s):  
M. I. Wood ◽  
L. L. Ames ◽  
J. E. Mcgarrah
Keyword(s):  
Near Field ◽  
Free Oxygen ◽  
Waste Package ◽  
Anoxic Conditions ◽  
Initial Oxygen Content ◽  
Initial Oxygen ◽  
Synthetic Groundwater ◽  
Hydrothermal Environment ◽  
Increasing Temperature

AbstractExperiments have been completed in the basalt-Tc-doped groundwater sys- tem to quantify the mobility of Tc in the waste package and near field envion- ment in a repository located in basalt. The experiments were completed using a batch sorption technique in which 8 rushed basalt and Tc-doped groundwater were reacted at 85, 100, 125 and 150 °C for periods of time up to 118 days. The water to rock ratio was 10:1 ml/g. In another set of experiments, basalt crushed under anoxic conditions and Tc-doped groundwater were reacted at 85°C at different water to rock ratios (10:3, 20:3, 40:3 and 80:3 ml/g).The rate and percentage of Tc removed from solution increased with increasing temperature and decreasing water to rock ratio. Also, basalt crushed under anoxic conditions removed >87% of Tc from solution at 85°C in 7 days while no Tc was removed from solution with basalt crushed in air at the same temperature after 118 days. These results are consistent with the hypothesis that (1) ferrous iron in basalt phases preferentially consumes oxygen and will not reduce Tcuntil all free oxygen in the system is consumed. Once oxygen is consumed, reduction of Tc is quite rapid. These data indicate that the potential exists in a basalt hydrothermal environment to satisfactorily immobilize Tc. Reliable application of these data will depend on experimental and theoretical estimates of oxygen consumption with time in the waste package environment following repository closure, subsequent saturation and long term hydrothermal reactions.

Pitting Studies Under Anoxic Conditions on Candidate Container Materials AISI 316L hMo and UHB 904L for The Disposal of HLW in Argillaceous Formations

2003 ◽  
Vol 807 ◽  
Author(s):  
Bruno Kursten ◽  
Frank Druyts
Keyword(s):  
Stainless Steel ◽  
Stainless Steels ◽  
Near Field ◽  
Austenitic Stainless Steels ◽  
Aisi 316L ◽  
Progressive Change ◽  
Anoxic Conditions ◽  
The Impact ◽  
Container Material

ABSTRACTStainless steel is being envisaged as the primary candidate container material for the final disposal of vitrified HLW in deep geological argillaceous formations in Belgium. The impact of an evolving underground repository environment, i.e. a progressive change from oxic to anoxic conditions (due to the consumption of entrapped oxygen), on the pitting behaviour of austenitic stainless steels AISI 316L hMo and UHB 904L was studied. CPP-experiments were performed in synthetic solutions, which are representative for the near-field chemistry of an underground repository. The solutions contained various amounts of Cl- (100–50,000 mg/L) at near-neutral pH. Experiments were conducted at 16 and 90°C.AISI 316L hMo and UHB 904L will not be subjected to immediate pitting problems neither under oxic, nor under anoxic conditions. However, AISI 316L hMo could present long-term pitting problems under oxic conditions. Pits are much easier initiated on AISI 316L hMo, for both oxic and anoxic conditions. The pits propagate in a rather similar manner under oxic conditions for both alloys, whereas under anoxic conditions the pits formed on AISI 316L hMo are much deeper. AISI 316L hMo is more susceptible to crevice attack.

Development, Application and Validation Of Models for Waste Package Long-Term Performance; Current Trends

1986 ◽  
Vol 84 ◽  
Author(s):  
Lars O. Werme ◽  
Bernd Grambow
Keyword(s):  
Spent Nuclear Fuel ◽  
Near Field ◽  
Relative Importance ◽  
Waste Package ◽  
Current Trends ◽  
Waste Forms ◽  
Long Term Performance ◽  
Term Performance ◽  
Development Application

AbstractCurrent trends in modelling waste package performance are reviewed mainly from the perspective of the Swedish SKB studies. Examples are given, which illustrate the approaches for modelling different waste forms, i.e. HLW glass and spent nuclear fuel, and candidate canister materials, such as copper and steel. The relative importance of thermodynamics, reaction kinetics and near-field transport are discussed.

The Spread of Pollutants from Harbour Sludge Depots

1984 ◽  
Vol 16 (3-4) ◽  
pp. 623-633
Author(s):  
M Loxham ◽  
F Weststrate
Keyword(s):  
Time Scales ◽  
Molecular Diffusion ◽  
Near Field ◽  
Parameter Analysis ◽  
Migration Patterns ◽  
Long Time ◽  
Dilution Effects ◽  
Short Time ◽  
Harbour Sludge

It is generally agreed that both the landfill option, or the civil techniques option for the final disposal of contaminated harbour sludge involves the isolation of the sludge from the environment. For short time scales, engineered barriers such as a bentonite screen, plastic sheets, pumping strategies etc. can be used. However for long time scales the effectiveness of such measures cannot be counted upon. It is thus necessary to be able to predict the long term environmenttal spread of contaminants from a mature landfill. A model is presented that considers diffusion and adsorption in the landfill site and convection and adsorption in the underlaying aquifer. From a parameter analysis starting form practical values it is shown that the adsorption behaviour and the molecular diffusion coefficient of the sludge, are the key parameters involved in the near field. The dilution effects of the far field migration patterns are also illustrated.

Autonomous near-field communication (NFC) sensors for long-term preventive care of fine art objects

2019 ◽  
Vol 285 ◽  
pp. 456-467 ◽  
Author(s):  
Matthew D. Steinberg ◽  
Christine Slottved Kimbriel ◽  
Lieve S. d'Hont
Keyword(s):  
Preventive Care ◽  
Near Field ◽  
Fine Art ◽  
Near Field Communication ◽  
Art Objects

scholarly journals Studying of 2D Titanium Carbide Structure by Raman Spectroscopy after Heat Treatment in Argon and Hydrogen Atmospheres

2017 ◽  
Vol 19 (2) ◽  
pp. 181 ◽  
Author(s):  
Olzhas Kaipoldayev ◽  
Ye. Mukhametkarimov ◽  
Renata Nemkaeva ◽  
G. Baigarinova ◽  
Madi Aitzhanov ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Raman Spectroscopy ◽  
Titanium Carbide ◽  
Functional Groups ◽  
Optimal Regime ◽  
Heat Treated ◽  
Initial Oxygen Content ◽  
Initial Oxygen ◽  
Tio2 Rutile ◽  
Total Disappearance

Herein we show the effect of heat treatment of two dimensional layered titanium carbide structure (Ti3C2Tx), so called MXene. As prepared MXene has functional groups -OH, -F, -Cl. In order to remove the functional groups we heat treated the MXene in Ar (with 0.01% O2) and H2 (with 0.01% H2O) atmospheres. We discovered the significant decrease in the amount of functional groups (-F and -Cl) and increase in the -O content, which refers to the oxidation of the material. Also we determined the optimal regime for Raman spectroscopy in order to avoid any changes in the structure of the material. We revealed that titanium carbide changes its structure at 700 °C and 900 °C into two different titanium dioxide modifications like rutile and anatase in Ar (with 0.01% O2) atmosphere. Also there are small changes occurred in Ti3C2Tx structure and formation of amorphous carbon after 700 °C treatment in H2 (with 0.01% H2O) atmosphere and formation of TiO2 (rutile) at 900 °C. Energydispersive X-ray spectroscopy (EDX) revealed the reduction of functional groups at 700 °C in both atmospheres and total disappearance of –F and –Cl and increasing the oxygen at 900 °C. The huge increase of oxygen by atomic percent, can be explained by the initial oxygen content in argon and hydrogen gases.

The Importance of Variables and Parameters in Radiolytic Chemical Kinetics Modeling

1988 ◽  
Vol 127 ◽  
Author(s):  
M. G. Piepho ◽  
P. J. Turner ◽  
P. W. Reimus
Keyword(s):  
Chemical Kinetics ◽  
Rate Constants ◽  
Transient Species ◽  
Geologic Repository ◽  
Species Concentration ◽  
Waste Package ◽  
Long Term Performance ◽  
Term Performance ◽  
Over Time

ABSTRACTRadiolysis may significantly affect the long-term performance of nuclear waste packages in a geologic repository. Radiolysis of available moisture and air in an unsaturated or saturated environment will create transient species that can significantly change the pH and/or Eh of the available moisture. These changes can influence rates of containment corrosion, waste form dissolution, and radionuclide solubilities and transport.Many of the pertinent radiochemical reactions are not completely understood, and most of the associated rate constants are poorly characterized. To help identify the important radiochemical reactions, rate constants, species, and environmental conditions, an importance theory code, SWATS (Sensitivity With Adjoint Theory-Sparse version)-LOOPCHEM, has been developed for the radiolytic chemical kinetics model in the radiolysis code LOOPCHEM. The LOOPCHEM code calculates the concentrations of various species in a radiolytic field over time. The SWATS-LOOPCHEM code efficiently calculates: 1) the importance (relative to a defined response of interest) of each species concentration over time, 2) the sensitivity of each parameter of interest, and 3) the importance of each equation in the radiolysis model. The calculated results will be used to guide future experimental and modeling work for determining the importance of radiolysis on waste package performance. A demonstration (the importance of selected concentrations and the sensitivities of selected parameters) of the SWATS-LOOPCHEM code is provided for illustrative purposes, and no attempt is made at this time to interpret the results for waste package performance assessment purposes.

Materials Interactions Relating to Long-Term Geologic Disposal of Nuclear Waste Glass

1986 ◽  
Vol 84 ◽  
Author(s):  
Ned E. Bibler ◽  
Carol M. Jantzen
Keyword(s):  
Nuclear Waste ◽  
Review Paper ◽  
Waste Glass ◽  
Waste Form ◽  
Glass Waste ◽  
Waste Package ◽  
Geologic Disposal ◽  
Nuclear Waste Glass ◽  
Backfill Materials

AbstractIn the geologic disposal of nuclear waste glass, the glass will eventually interact with groundwater in the repository system. Interactions can also occur between the glass and other waste package materials that are present. These include the steel canister that holds the glass, the metal overpack over the canister, backfill materials that may be used, and the repository host rock. This review paper systematizes the additional interactions that materials in the waste package will impose on the borosilicate glass waste form-groundwater interactions. The repository geologies reviewed are tuff, salt, basalt, and granite. The interactions emphasized are those appropriate to conditions expected after repository closure, e.g. oxic vs. anoxic conditions. Whenever possible, the effect of radiation from the waste form on the interactions is examined. The interactions are evaluated based on their effect on the release and speciation of various elements including radionuclides from the glass. It is noted when further tests of repository interactions are needed before long-term predictions can be made.

scholarly journals Phosphorus Inactivation in Lake Sediments Using Calcite Materials and Controlled Resuspension—Mechanism and Efficiency

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 223
Author(s):  
Agnieszka Bańkowska-Sobczak ◽  
Aurelia Blazejczyk ◽  
Elisabeth Eiche ◽  
Uwe Fischer ◽  
Zbigniew Popek
Keyword(s):  
Adsorption Capacity ◽  
Soluble Reactive Phosphorus ◽  
High Dose ◽  
Eutrophic Lakes ◽  
Precipitated Calcium Carbonate ◽  
Anoxic Conditions ◽  
P Fraction ◽  
Reactive Phosphorus ◽  
High Doses

The efficiency and mechanism of orthophosphate—soluble reactive phosphorus (SRP)—inactivation in eutrophic lakes using controlled resuspension and calcite application into the sediment were investigated in this study. Two calcite materials, industrially produced precipitated calcium carbonate (PCC) and natural ground limestone (GCC), were tested in short-term batch experiments and long-term sediment incubations under oxic and anoxic conditions. Maximum SRP adsorption capacity calculated using Langmuir model for PCC (3.11 mg PO43− g−1) was 6 times higher than of GCC (0.43 mg PO43− g−1), reflecting substantial difference in the surface area of calcite materials (12.36 and 1.72 m2 g−1, respectively). PCC applied into the sediment during controlled resuspension reduced SRP release by 95% (oxic) and 78% (anoxic incubation) at medium dose (0.75 kg m−2) and suppressed it completely at high dose (1.5 kg m−2) for at least 3 months, irrespectively of incubation conditions. The maximum achieved reduction of SRP release using GCC was also meaningful: 78% under oxic and 56% under anoxic conditions, but this required very high doses of this material (6 kg m−2). Mechanisms of SRP inactivation by calcites were: (1) adsorption of SRP during application into the resuspended sediment and (2) precipitation of calcium-phosphate compounds (Ca-PO4) during subsequent incubation, which was reflected in a substantial increase in the HCl-P fraction (phosphorus extractable in 0.5 M HCl) in sediments enriched with calcite, irrespectively of oxygen presence. However, anoxia strongly promoted the formation of this fraction: the rise of HCl-P was 2–6 times higher in anoxic than in oxic conditions, depending on the dose and form of calcite applied. The results showed that SRP inactivation using the controlled resuspension method is only successful if highly efficient reactive materials are used, due to large amount of SRP being released from sediment during resuspension. Thus, calcite materials exhibiting high adsorption capacity should be used in this lakes’ restoration technology to ensure fast and sufficient SRP inactivation. The rise in the HCl-P fraction in sediment suggests SRP inactivation through precipitation of relatively stable Ca-PO4 minerals, which makes calcite a suitable agent for sustainable, long term SRP inactivation. As anoxic conditions promoted formation of these compounds, calcite seems to be a promising SRP inactivation agent in highly reductive sediments.

scholarly journals Near-Field Measurement of Six Degrees of Freedom Mining-Induced Tremors in Lower Silesian Copper Basin

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6801
Author(s):  
Krzysztof Fuławka ◽  
Witold Pytel ◽  
Bogumiła Pałac-Walko
Keyword(s):  
Seismic Wave ◽  
Degrees Of Freedom ◽  
Seismic Waves ◽  
Near Field ◽  
High Energy ◽  
Rotational Component ◽  
Empirical Formulas ◽  
Six Degrees Of Freedom ◽  
The Impact

The impact of seismicity on structures is one of the key problems of civil engineering. According to recent knowledge, the reliable analysis should be based on both rotational and translational components of the seismic wave. To determine the six degrees of freedom (6-DoF) characteristic of mining-induced seismicity, two sets of seismic posts were installed in the Lower Silesian Copper Basin, Poland. Long-term continuous 6-DoF measurements were conducted with the use of the R-1 rotational seismometer and EP-300 translational seismometer. In result data collection, the waveforms generated by 39 high-energy seismic events were recorded. The characteristic of the rotational component of the seismic waves were described in terms of their amplitude and frequency characteristics and were compared with translational measurements. The analysis indicated that the characteristic of the rotational component of the seismic wave differs significantly in comparison to translational ones, both in terms of their amplitude and frequency distribution. Also, attenuation of rotational and translational components was qualitatively compared. Finally, the empirical formulas for seismic rotation prediction in the Lower Silesian Copper Basin were developed and validated.

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