scholarly journals Hydrothermal Interaction of Topopah Spring Tuff With J-13 Water as a Function of Temperature

1984 ◽  
Vol 44 ◽  
Author(s):  
Kevin G. Knauss ◽  
J. M. Delany ◽  
W. J. Beiriger ◽  
D. W. Peifer
Keyword(s):  
Geochemical Modeling ◽  
Near Field ◽  
Secondary Phases ◽  
Accelerated Tests ◽  
Short Term ◽  
Nuclear Waste Storage ◽  
Waste Storage ◽  
J 13 ◽  
Modeling Code

AbstractIn support of the Nevada Nuclear Waste Storage Investigations Project experiments were conducted to study the hydrothermal interaction of rock and water representative of a potential repository in tuff. These experiments provided data relevant to near-field repository conditions that can be used to: assess the ability to use “accelerated” tests based on the SA/V (surface area/volume) parameter and temperature; allow the measurement of chemical changes in phases present in the tuff before reaction as well as the identification and chemical analysis of secondary phases resulting from hydrothermal reactions; and demonstrate the usefulness of geochemical modeling in a repository environment using the EQ3/6 thermodynamic/kinetic geochemical modeling code. Crushed tuff and polished wafers of tuff were reacted with a natural ground water in Dickson-type gold-cell rocking autoclaves which were periodically sampled under insitu conditions. Results were compared with predictions based on the EQ3/6 geochemical modeling code. Eight short-term experiments (2 to 3 months) at 150°C and 250°C have been completed using tuff from both drillcore and outcrop. Long-term experiments at 90°C and 150°C using drillcore polished wafers are in progress. This paper will focus on the results of the 150°C and 250°C experiments using drillcore polished wafers.

scholarly journals Selection of Barrier Metals for a Waste Package in Tuff

1983 ◽  
Vol 26 ◽  
Author(s):  
E. W. yyRussell ◽  
R. D. McCright ◽  
W. C. O'Neal
Keyword(s):  
Nuclear Waste ◽  
Lawrence Livermore National Laboratory ◽  
Near Field ◽  
National Laboratory ◽  
Test Site ◽  
Management Program ◽  
Nuclear Waste Storage ◽  
Waste Storage ◽  
High Level ◽  
Selection Of

ABSTRACTThe Nevada Nuclear Waste Storage Investigations (NNWSI) project under the Civilian Radioactive Waste Management Program is planning a repository at Yucca Mountain at the Nevada Test Site for isolation of high-level nuclear waste. Lawrence Livermore National Laboratory is developing designs for an engineered barrier system containing several barriers such as the waste form, a canister and/or an overpack, packing, and near field host rock. In this paper we address the selection of metal containment barriers.

scholarly journals Reactive transport modelling of long-term interactions between iron and MX-80 bentonite

2021 ◽  
Vol 1 ◽  
pp. 169-170
Author(s):  
M. Carme Chaparro ◽  
Nicolas Finck ◽  
Volker Metz ◽  
Horst Geckeis
Keyword(s):  
Carbon Steel ◽  
Numerical Model ◽  
Reactive Transport ◽  
Transport Model ◽  
Corrosion Products ◽  
Mineral Dissolution ◽  
Secondary Phases ◽  
Short Term ◽  
Complexation Reactions

Abstract. The geological disposal in deep bedrock repositories is the preferred option for the management of high-level radioactive waste. In some of these concepts, carbon steel is considered as potential canister material and bentonites are planned as backfill material to protect metal waste containers. Therefore, a 1D radial reactive transport model has been developed in order to better understand the processes occurring during the long-term iron–bentonite interaction. The conceptual model accounts for diffusion, chemistry of the porewater and aqueous complexation reactions, mineral dissolution/precipitation and absorption, at a constant temperature of 25 ∘C under anoxic conditions. The geometry of the axisymmetric model reflects the canister–bentonite interface and the bentonite. The primary phases considered are montmorillonitic smectite, quartz, muscovite, albite, illite, pyrite and calcite. We assume that carbon steel is composed only of iron. The potential secondary phases considered are from reported experiments, such as magnetite, nontronitic smectite, greenalite, cronstedtite and siderite. The numerical model results suggest that at the iron–bentonite interface, Fe is adsorbed at the smectite surface via ion exchange in the short term and it is consumed by formation of the secondary phases in the long term. Furthermore, calcite precipitates are due to cation exchange in the short term and due to montmorillonitic smectite dissolution in the long term. The numerical model predicts the precipitation of nontronitic smectite, magnetite and greenalite as corrosion products. Results further reveal a significant increase in pH in the long term, whereas dissolution/precipitation reactions result in limited variations of the porosity. Progressing bentonite dissolution owing to the rising pH and concomitantly increasing silicate concentrations in the porewater induce formation of Fe-silicates as corrosion products at the expense of magnetite. A sensitivity analysis has also been performed to study the effect of selected parameters, such as corrosion rate, diffusion coefficient and composition of the porewater, on the corrosion products. Overall, outcomes suggest that pH and concentration of dissolved Si play an important role in corrosion mechanisms. The predicted main secondary phases in the long term are Fe-silicate minerals. Thus, such phases deserve further attention as possible chemical barriers for radionuclide migration in the repository near-field.

Feasibility of polyetherketone (PEK) composites: a solution for long-term nuclear waste storage

2016 ◽  
Vol 10 (3) ◽  
pp. 257 ◽  
Author(s):  
G. Ajeesh ◽  
Shantanu Bhowmik ◽  
Venugopal Sivakumar ◽  
Lalit Varshney ◽  
Virendra Kumar ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Nuclear Waste Storage ◽  
Waste Storage

scholarly journals Gas discrimination by simultaneous sound velocity and attenuation measurements using uncoated capacitive micromachined ultrasonic transducers

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Luis Iglesias Hernandez ◽  
Priyadarshini Shanmugam ◽  
Jean-François Michaud ◽  
Daniel Alquier ◽  
Dominique Certon ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Ultrasonic Transducers ◽  
Multiple Reflections ◽  
Nuclear Waste Storage ◽  
Capacitive Micromachined Ultrasonic Transducers ◽  
Long Term Stability ◽  
Waste Storage ◽  
Potential Applications ◽  
Hazardous Gases

AbstractChemically functionalized or coated sensors are by far the most employed solution in gas sensing. However, their poor long term stability represents a concern in applications dealing with hazardous gases. Uncoated sensors are durable but their selectivity is poor or non-existent. In this study, multi-parametric discrimination is used as an alternative to selectivity for uncoated capacitive micromachined ultrasonic transducers (CMUTs). This paper shows how measuring simultaneously the attenuation coefficient and the time of flight under different nitrogen mixtures allows to identify hydrogen, carbon dioxide and methane from each other and determine their concentration along with identification of temperature and humidity drifts. Theoretical comparison and specific signal processing to deal with the issue of multiple reflections are also presented. Some potential applications are monitoring of refueling stations, vehicles and nuclear waste storage facilities.

scholarly journals Development, characterization, and first application of a resonant laser secondary neutral mass spectrometry setup for the research of plutonium in the context of long-term nuclear waste storage

2021 ◽  
Author(s):  
Daniela Schönenbach ◽  
Felix Berg ◽  
Markus Breckheimer ◽  
Daniel Hagenlocher ◽  
Pascal Schönberg ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Spatial Resolution ◽  
Nuclear Waste ◽  
Heterogeneous Materials ◽  
Nuclear Waste Repository ◽  
Nuclear Waste Storage ◽  
Waste Storage ◽  
Tof Sims ◽  
Resonant Laser

AbstractPlutonium is a major contributor to the radiotoxicity in a long-term nuclear waste repository; therefore, many studies have focused on interactions of plutonium with the technical, geotechnical, and geological barriers of a possible nuclear waste storage site. In order to gain new insights into the sorption on surfaces and diffusion of actinides through these complex heterogeneous materials, a highly sensitive method with spatial resolution is required. Resonant laser secondary neutral mass spectrometry (Laser-SNMS) uses the spatial resolution available in time-of-flight secondary ion mass spectrometry (TOF-SIMS) in combination with the high selectivity, sensitivity, and low background noise of resonance ionization mass spectrometry (RIMS) and is, therefore, a promising method for the study and analysis of the geochemical behavior of plutonium in long-term nuclear waste storage. The authors present an approach with a combined setup consisting of a commercial TOF-SIMS instrument and a Ti:sapphire (Ti:Sa) laser system, as well as its optimization, characterization, and improvements compared to the original proof of concept by Erdmann et al. (2009). As a first application, the spatial distributions of plutonium and other elements on the surface of a pyrite particle and a cement thin section were measured by Laser-SNMS and TOF-SIMS, respectively. These results exemplify the potential of these techniques for the surface analysis of heterogeneous materials in the context of nuclear safety research.

scholarly journals Transport and Reaction Kinetics at the Glass:Solution Interface Region: Results of Repository-Oriented Leaching Experiments

1986 ◽  
Vol 84 ◽  
Author(s):  
Teofilo A. Abrajano ◽  
John K. Bates
Keyword(s):  
Interdiffusion Zone ◽  
Savannah River ◽  
Nuclear Waste Storage ◽  
Γ Radiation ◽  
Waste Storage ◽  
Leachate Solution ◽  
Leaching Experiments ◽  
Low Solubility ◽  
Water Species

AbstractRepository-oriented leaching experiments involving Savannah River Laboratory (SRL) 165 type glass under a γ-radiation field (1= 0.2 × 104 R/h) have been performed by the Nevada Nuclear Waste Storage Investigations (NNWSI) project. In this communication, we discuss glass surface analyses obtained by SEM, nuclear resonance profiling, and SIMS together with leachate solution data in relation to a mechanism that couples diffusion, hydrolysis (etching and gelation), and precipitation to qualitatively describe the release of different glass components to the leachant solutions. The release of mobile (e.g., Li) and partly mobile (e.g., B) species is controlled primarily by interdiffusion with water species across the interdiffusion zone. Glass components that are immobile in the interdiffusion zone are released to the solution by etching. For prediction of long-term steady-state concentrations of glass components with low solubility, the relative rates of release from the glass and secondary mineral precipitation must be taken into account.

Zeolitization of Glassy Topopah Spring Tuff Under Hydrothermal Conditions

1986 ◽  
Vol 84 ◽  
Author(s):  
Kevin G. Knauss
Keyword(s):  
Nuclear Waste ◽  
Geochemical Modeling ◽  
Nuclear Waste Repository ◽  
Hydrothermal Conditions ◽  
Nuclear Waste Storage ◽  
Model Calculations ◽  
Geochemical Model ◽  
Waste Storage ◽  
Lower Temperature ◽  
Term Performance

AbstractIn support of the Nevada Nuclear Waste Storage Investigations Project experiments were conducted to study the effects of heat generated by a nuclear waste repository in densely welded, devitrified tuff on the underlying, compositionally-equivalent glassy tuff at Yucca Mtn. Solid wafers of glassy tuff were reacted with a dilute ground water for several months at 150°C and 250°C at 100 bars pressure in Dickson-type, gold-bag rocking autoclaves. The in-situ chemistry of the hydrothermal fluids was modeled and the chemical affinities for all possible mineral precipitation reactions (contained within the extensive database) were calculated using the EQ3/6 program.In the 250°C experiment the calculations suggest that a zeolite mineral would be expected to form. Analyses of the run products showed that not only had the wafer been extensively corroded and the glass shards replaced by clinoptilolite, but pure clinoptilolite had precipitated directly from solution. In the 150°C experiment, although clay minerals were thermodynamically favored to form in the first half of the experiment, by the end of the run a zeolite mineral was predicted to form. Analyses of the run products showed no well-formed secondary minerals (clays or zeolites) had formed. At the lower temperature the effects of precipitation kinetics may preclude the formation of the zeolite within the time span of this experiment. In general the observations are in relatively good agreement with the geochemical model calculations. This type of study demonstrates the interpretive/predictive capabilities of a combined experimental/geochemical modeling approach to studies of nuclear waste isolation. This combined approach will aid in satisfying licensing requirements to assure long-term performance.

Sign in / Sign up

Export Citation Format

Share Document