A scaling approach for retention properties of crystalline rock: Case study of the in‐situ long‐term sorption and diffusion experiment (LTDE‐SD) at the Äspö Hard Rock Laboratory in Sweden

2021 ◽  
Author(s):  
Yukio Tachi ◽  
Tsuyoshi Ito ◽  
Björn Gylling
Keyword(s):  
Hard Rock ◽  
Crystalline Rock ◽  
Diffusion Experiment ◽  
Rock Laboratory ◽  
And Diffusion

Modeling of an in-situ diffusion experiment in granite at the Grimsel Test Site

2014 ◽  
Vol 1665 ◽  
pp. 85-91 ◽  
Author(s):  
Josep M. Soler ◽  
Jiri Landa ◽  
Vaclava Havlova ◽  
Yukio Tachi ◽  
Takanori Ebina ◽  
...  
Keyword(s):  
Effective Diffusion ◽  
Test Site ◽  
Diffusion Experiment ◽  
Bulk Rock ◽  
Disturbed Zone ◽  
Mean Grain Size ◽  
Grimsel Test Site ◽  
In Situ Diffusion

ABSTRACTMatrix diffusion is a key process for radionuclide retention in crystalline rocks. Within the LTD project (Long-Term Diffusion), an in-situ diffusion experiment in unaltered non-fractured granite was performed at the Grimsel Test Site (www.grimsel.com, Switzerland). The tracers included 3H as HTO, 22Na+, 134Cs+ and 131I- with stable I- as carrier.The dataset (except for 131I- because of complete decay) was analyzed with different diffusion-sorption models by different teams (NAGRA / IDAEA-CSIC, UJV-Rez, JAEA, Univ. Poitiers) using different codes, with the goal of obtaining effective diffusion coefficients (De) and porosity (ϕ) or rock capacity (α) values. A Borehole Disturbed Zone (BDZ), which was observed in the rock profile data for 22Na+ and 134Cs+, had to be taken into account to fit the experimental observations. The extension of the BDZ (1-2 mm) was about the same magnitude as the mean grain size of the quartz and feldspar grains.De and α values for the different tracers in the BDZ are larger than the respective values in the bulk rock. Capacity factors in the bulk rock are largest for Cs+ (strong sorption) and smallest for 3H (no sorption). However, 3H seems to display large α values in the BDZ. This phenomenon will be investigated in more detail in a second test starting in 2013.

scholarly journals ENVIRONMENTAL POLLUTION BY WASTEWATER FROM BROWN COAL PROCESSING ¬ A REMEDIATION CASE STUDY IN GERMANY

2014 ◽  
Vol 22 (1) ◽  
pp. 71-83 ◽  
Author(s):  
Arndt Wiessner ◽  
Jochen A. Müller ◽  
Peter Kuschk ◽  
Uwe Kappelmeyer ◽  
Matthias Kästner ◽  
...  
Keyword(s):  
Environmental Pollution ◽  
Large Scale ◽  
Pilot Scale ◽  
Wastewater Disposal ◽  
Interdisciplinary Approaches ◽  
Phenolic Wastewater ◽  
Term Monitoring

The large scale of the contamination by the former carbo-chemical industry in Germany requires new and often interdisciplinary approaches for performing an economically sustainable remediation. For example, a highly toxic and dark-colored phenolic wastewater from a lignite pyrolysis factory was filled into a former open-cast pit, forming a large wastewater disposal pond. This caused an extensive environmental pollution, calling for an ecologically and economically acceptable strategy for remediation. Laboratory-scale investigations and pilot-scale tests were carried out. The result was the development of a strategy for an implementation of full-scale enhanced in situ natural attenuation on the basis of separate habitats in a meromictic pond. Long-term monitoring of the chemical and biological dynamics of the pond demonstrates the metamorphosis of a former highly polluted industrial waste deposition into a nature-integrated ecosystem with reduced danger for the environment, and confirmed the strategy for the chosen remediation management.

scholarly journals Can post-mortem MRI be used as a proxy for in vivo? A case study

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Baayla D C Boon ◽  
Petra J W Pouwels ◽  
Laura E Jonkman ◽  
Matthijs J Keijzer ◽  
Paolo Preziosa ◽  
...  
Keyword(s):  
White Matter ◽  
Rating Scales ◽  
Brain Volume ◽  
Brain Mri ◽  
Post Mortem ◽  
Early Onset Alzheimer’S Disease ◽  
And Diffusion

Abstract Post-mortem in situ MRI has been used as an intermediate between brain histo(patho)logy and in vivo imaging. However, it is not known how comparable post-mortem in situ is to ante-mortem imaging. We report the unique situation of a patient with familial early-onset Alzheimer’s disease due to a PSEN1 mutation, who underwent ante-mortem brain MRI and post-mortem in situ imaging only 4 days apart. T1-weighted and diffusion MRI was performed at 3-Tesla at both time points. Visual atrophy rating scales, brain volume, cortical thickness and diffusion measures were derived from both scans and compared. Post-mortem visual atrophy scores decreased 0.5–1 point compared with ante-mortem, indicating an increase in brain volume. This was confirmed by quantitative analysis; showing a 27% decrease of ventricular and 7% increase of whole-brain volume. This increase was more pronounced in the cerebellum and supratentorial white matter than in grey matter. Furthermore, axial and radial diffusivity decreased up to 60% post-mortem whereas average fractional anisotropy of white matter increased approximately 10%. This unique case study shows that the process of dying affects several imaging markers. These changes need to be taken into account when interpreting post-mortem MRI to make inferences on the in vivo situation.

scholarly journals Permeability Enhancement and Fracture Development of Hydraulic In Situ Experiments in the Äspö Hard Rock Laboratory, Sweden

2018 ◽  
Vol 52 (2) ◽  
pp. 495-515 ◽  
Author(s):  
Günter Zimmermann ◽  
Arno Zang ◽  
Ove Stephansson ◽  
Gerd Klee ◽  
Hana Semiková
Keyword(s):  
Hard Rock ◽  
Permeability Enhancement ◽  
Rock Laboratory ◽  
Fracture Development ◽  
In Situ Experiments

scholarly journals Comparison between in situ and laboratory diffusion studies of HTO and halides in Opalinus Clay from the Mont Terri

2004 ◽  
Vol 92 (9-11) ◽  
Author(s):  
Etienne Tevissen ◽  
J. M. Soler ◽  
P. Montarnal ◽  
A. Gautschi ◽  
Luc R. Van Loon
Keyword(s):  
Tritiated Water ◽  
Opalinus Clay ◽  
Diffusion Experiment ◽  
Diffusion Technique ◽  
Diffusion Studies ◽  
Through Diffusion ◽  
Mont Terri

SummaryA long-term single-borehole diffusion experiment (DI) using tritiated water (HTO) and stable iodide (All HTO results obtained with a through diffusion technique are within the same range as those obtained in the

scholarly journals Measurement report: Changing characteristics of atmospheric CH<sub>4</sub> in the Tibetan Plateau: records from 1994 to 2019 at the Mount Waliguan station

2021 ◽  
Vol 21 (1) ◽  
pp. 393-413
Author(s):  
Shuo Liu ◽  
Shuangxi Fang ◽  
Peng Liu ◽  
Miao Liang ◽  
Minrui Guo ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Atmospheric Methane ◽  
Continuous Increase ◽  
Northern India ◽  
Source Regions ◽  
City Regions

Abstract. A 26-year, long-term record of atmospheric methane (CH4) measured in situ at the Mount Waliguan (WLG) station, the only World Meteorological Organization (WMO) and Global Atmosphere Watch (GAW) global station in inland Eurasia, is presented. Overall, a nearly continuous increase in atmospheric CH4 was observed at WLG, with a yearly growth rate of 5.1±0.1 parts per billion (ppb) per year during 1994–2019, except for some particular periods with near-zero or negative values, e.g., 1999–2000 and 2004–2006. The average CH4 mole fraction was only 1799.0±0.4 ppb in 1994 but increased to about 133 ppb and reached a historic level of 1932.0±0.1 ppb in 2019. The case study in the Tibetan Plateau showed that the atmospheric CH4 increased rapidly. During some special periods, it is even larger than that of city regions (e.g., 6.7±0.2 ppb yr−1 in 2003–2007). Generally, the characteristics of CH4 varied in different observing periods as follows: (i) the diurnal cycle has become apparent and the amplitudes of the diurnal or seasonal cycles increased over time; (ii) the wind sectors with elevated CH4 mole fractions switched from ENE-E-ESE-SE-SSE sectors (wind directions) in early periods to NNE-NE-ENE-E sectors in later years; (iii) the area of source regions increased as the years progressed, and strong sources shifted from northeast (city regions) to southwest (northern India); and (iv) the annual growth rates in recent years (e.g., 2008–2019) were significantly larger than those in the early periods (e.g., 1994–2007).

scholarly journals Assessing the efficiency of a “buried wall” barrier in the establishment of near-surface long-term storage and disposal facilities for RW

2021 ◽  
Vol 14 (1) ◽  
pp. 96-105
Author(s):  
V. V. Suskin ◽  
◽  
I. V. Kapyrin ◽  
F. V. Grigorev ◽  
◽  
...  
Keyword(s):  
Near Surface ◽  
Transfer Processes ◽  
Long Term Storage ◽  
Mass Transfer Processes ◽  
High Degree ◽  
The Impact ◽  
Term Storage

The article evaluates the impact of a “buried wall” barrier on the long-term safety during the long-term storage1 or in-situ disposal of nuclear legacy facilities, in particular, industrial reservoirs, as well as during the development of near-surface disposal facilities for radioactive waste (RWDF). For assessment purposes, filtration and mass transfer processes have been numerically modelled in the GeRa code based on a case study of a reference near-surface facility. The study explores in which way the available covering screen affects the dynamics of contaminant spread. It evaluates the sensitivity of the results to the dispersion parameter commonly characterized by a high degree of uncertainty.

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