State Of the Art Report in the fields of numerical analysis and scientific computing. Final version as of 16/02/2020 deliverable D4.1 of the HORIZON 2020 project EURAD.: European Joint Programme on Radioactive Waste Management

Document information Project Acronym EURAD Project Title European Joint Programme on Radioactive Waste Management Project Type European Joint Programme (EJP) EC grant agreement No. 847593 Project starting / end date 1 st June 2019-30 May 2024 Work Package No. 4 Work Package Title Development and Improvement Of NUmerical methods and Tools for modelling coupled processes Work Package Acronym DONUT Deliverable No. 4.

Structure of Dark Triad Dirty Dozen Across Eight World Regions

The Dark Triad (i.e., narcissism, psychopathy, Machiavellianism) has garnered intense attention over the past 15 years. We examined the structure of these traits’ measure—the Dark Triad Dirty Dozen (DTDD)—in a sample of 11,488 participants from three W.E.I.R.D. (i.e., North America, Oceania, Western Europe) and five non-W.E.I.R.D. (i.e., Asia, Middle East, non-Western Europe, South America, sub-Saharan Africa) world regions. The results confirmed the measurement invariance of the DTDD across participants’ sex in all world regions, with men scoring higher than women on all traits (except for psychopathy in Asia, where the difference was not significant). We found evidence for metric (and partial scalar) measurement invariance within and between W.E.I.R.D. and non-W.E.I.R.D. world regions. The results generally support the structure of the DTDD

Deciphering pore-level precipitation mechanisms

Abstract Mineral precipitation and dissolution in aqueous solutions has a significant effect on solute transport and structural properties of porous media. The understanding of the involved physical mechanisms, which cover a large range of spatial and temporal scales, plays a key role in several geochemical and industrial processes. Here, by coupling pore scale reactive transport simulations with classical nucleation theory, we demonstrate how the interplay between homogeneous and heterogeneous precipitation kinetics along with the non-linear dependence on solute concentration affects the evolution of the system. Such phenomena are usually neglected in pure macroscopic modelling. Comprehensive parametric analysis and comparison with laboratory experiments confirm that incorporation of detailed microscale physical processes in the models is compulsory. This sheds light on the inherent coupling mechanisms and bridges the gap between atomistic processes and macroscopic observations

Zr-containing layered double hydroxides: Synthesis, characterization, and evaluation of thermodynamic properties

Layered doubled hydroxides (LDH), consisting of positively charged octahedral brucite-type layers and interlayer anions, have been widely studied in the last decades because of their ability to control the mobility of various anions and cations in the environment. LDH may be relevant to the safety case of nuclear waste repositories due to their retention potential of anionic radionuclide species, for example 129I or 79Se. So far few studies were dedicated to Zr incorporation into LDH, which might be a relevant secondary phase in the repository environment due to the possible corrosion of Zr-bearing nuclear materials and the presence of 93Zr, a long-lived fission and activation product, in various nuclear waste streams. The focus of our study was to synthesize and characterize Cl-bearing Mg-Al-LDH (MgxAlyZrz(OH)2Cl(2x + 3y + 4z − 2)) with different Zr-content and to evaluate their thermodynamic properties, especially their solubility as a function of temperature. The LDH were synthesized by a coprecipitation method at temperatures between 298.15 and 343.15 K, aiming at Zr/(Zr + Al) ratios of 0.1 and 0.4, respectively. Our analytical techniques combining X-ray diffraction and scanning electron microscopy indicated that up to 5 mol% Zr were incorporated into the brucite layer of the LDH. At higher Zr concentrations the precipitation of an amorphous hydrous Zr-oxide was observed. The structural uptake of Zr was lower than the value reported in literature for CO32– bearing LDH, suggesting that the interlayer anions may play a role with regard to the Zr uptake in the brucite layer. At low Zr contents, well defined crystalline LDH with the composition Mg0.72Al0.22Zr0.025(OH)2Cl0.20 were obtained at all syntheses temperatures. The solubility of this LDH decreases slightly with temperature and the stoichiometric saturation constant was found to satisfy the Van't Hoff equation. The thermodynamic properties of the Zr LDH (Gibbs free energy of formation, ΔG°f) were determined by considering an approach based on solubility data and Gibbs energy minimization and a calorimetric approach. The enthalpy of formation (ΔH°f) and the lattice entropy (S°) of the Zr-LDH were determined using calorimetric measurements to be − 1181.01 ± 4.98 kJ mol− 1 and 83.9 J mol− 1 K− 1 respectively. Considering contribution of the configurational entropy, the standard entropy, S°, was evaluated at 97 ± 7 J mol− 1 K− 1. The ΔG°f for Mg0.72Al0.22Zr0.025(OH)2Cl0.20*0.69H2O obtained from experimental measurements and that predicted by theory were evaluated at − 1046 ± 7 and − 1046 ± 13 kJ mol− 1 respectively. Thus, the combination of solubility data and Gibbs energy minimization can be considered as good alternative for the evaluation of ΔG°f of LDH

Benchmarking of reactive transport codes for 2D simulations with mineral dissolution–precipitation reactions and feedback on transport parameters

Porosity changes due to mineral dissolution–precipitation reactions in porous media and the resulting impact on transport parameters influence the evolution of natural geological environments or engineered underground barrier systems. In the absence of long-term experimental studies, reactive transport codes are used to evaluate the long-term evolution of engineered barrier systems and waste disposal in the deep underground. Examples for such problems are the long-term fate of CO2 in saline aquifers and mineral transformations that cause porosity changes at clay–concrete interfaces. For porosity clogging under a diffusive transport regime and for simple reaction networks, the accuracy of numerical codes can be verified against analytical solutions. For clogging problems with more complex chemical interactions and transport processes, numerical benchmarks are more suitable to assess model performance, the influence of thermodynamic data, and sensitivity to the reacting mineral phases. Such studies increase confidence in numerical model descriptions of more complex, engineered barrier systems. We propose a reactive transport benchmark, considering the advective–diffusive transport of solutes; the effect of liquid-phase density on liquid flow and advective transport; kinetically controlled dissolution–precipitation reactions causing porosity, permeability, and diffusivity changes; and the formation of a solid solution. We present and analyze the results of five participating reactive transport codes (i.e., CORE2D, MIN3P-THCm, OpenGeoSys-GEM, PFLOTRAN, and TOUGHREACT). In all cases, good agreement of the results was obtained