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[en] Pore-scale models represent an appealing approach for obtaining a more accurate and mechanistic description of physical and chemical processes in heterogeneous porous media such as cement-based materials. For this purpose, a coupled code, which is able to calculate reactive transport processes in porous media on the pore scale using the Lattice-Boltzmann approach, is developed. The aim of this coupled code is to simulate chemicallydriven alteration and degradation processes and solute transport in cement-based materials. Geometrical changes of the pore structure due to dissolution and precipitation processes at the microscopic scale can have significant effects on the macroscopic hydrodynamic properties of porous media. In this context, the current development status and the techniques used to simulate precipitation processes on the pore-scale in a realistic way are outlined. A model consisting of a gypsum containing pore leading to ettringite precipitation on monosulfoaluminate is depicted to illustrate the effect of the recent development iteration.
[en] This study is a prior step towards the modelling of real interactions between hydrated OPC and groundwater from Josef Underground Facility (GW Josef) with or without addition of Czech bentonite under in-situ conditions (10°C) and by heating (95°C) performed in cooperation with Czech laboratories (UJV and CTU-CEG) as a part of WP1. In this contribution, bentonite dissolution and formation of new phases in model cement-leach aqueous solution has been studied by geochemical calculations in PhreeqC. Compositions of the Czech commercial Bentonite 75 (denoted as B75) and the hydrated OPC (CEM II A-S 42.5R) taken into consideration by modelling were based on experimental XDR analyses. The lack of OPC in identified phases (no S-phases, no amorphous Na/K-compounds, no quantitative information) led to a simplification of modelled systems. In the systems without bentonite (hydrated OPC contacted with GW Josef) initial concentration of dominant cations Na/K-species has been raised, with the aim to adjust ionic strength and pH, respecting real analysis of cement leachates in liquid phases performed for nine months of interaction. To improve this model, further XRF analysis of hydrated OPC is needed, as the prediction of the C/S ratio is necessary. Influences of phase ratio m : m : m and temperature on dissolution, forming phases or composition of pore water were studied. Despite the simplification of the model, the results (e.g., formation of C-A-S-H and phases based on CaCO) on the boundary of cement and bentonite are in an agreement with experiments.
[en] Cementitious materials behaviour must be predictable through the lifetime of nuclear waste repository to ensure the functionality of the engineered barrier system. Thermodynamic modelling is a useful tool to predict the behaviour of the cementitious materials in extremely long time span. Together with the experimental results, modelling provides potential scenarios of cementitious materials behaviour during the lifetime of the repository. Largest uncertainties that are related to the thermodynamic modelling of the cementitious materials are related to calcium-silicate-hydrates, the main reaction product of cementitious materials. The goal of the current study was to define modelling parameters for calcium-silicate-hydrates that are credible and transparent. Ion activity product and Gibbs formation energies were calculated from various solution compositions. Calculated results enable determination of solubility products and formation energies with varying silicate chain lengths and CaO/SiO-ratios. Dimeric silicate chain lengths were arbitrarily selected for further modelling. Calcium-silicate-hydrates were modelled as a solid solution and the results were compared to the experimentally measured pH, calcium and silicon concentrations. Modelled results were in good agreement with the measured results. In the future, leaching of calcium-silicate-hydrates will be modelled and compared with the experimental results. Silicate chain length and solid solution end-members effects on the modelling will be further investigated.
[en] This book first discusses the role hydrogen can have in energy transition. For this purpose, it proposes an overview of its present economy, markets and actors, of its possible role in economy decarbonization, and of the role of electrolytic hydrogen in public policies. Then, it presents and comments the different systems of production of de-carbonated hydrogen by using water and electricity (thermolysis, photo-catalysis, electrolysis), by using biomass (pyrolysis and gasification, biogas reforming, thermochemical process, biological processes), or by using hydrocarbons with CO2 capture and storage. It addresses the various aspects related to hydrogen packing: safety (standards, regulations), storage (technologies) and distribution (by ducts, road or rail transport, ship transport). After a comparison of the different production processes in terms of energy consumption, CO2 emissions, and costs, the different actual or possible usages of hydrogen are overviewed: for industry, transport and building decarbonization, for electric power production
[en] X-ray tomography has entered the industrial world. The last Nikon XTH450 machine acquired by Sematec Metrology can control the sizes of metal pieces up to a diameter of 400 mm and a length of 600 mm. The accuracy is in the 10, 20 μm range and the spatial resolution reaches 30 at 400 μm. This X-ray digital tomograph will allow Sematec Metrology to work on any metal parts made of steel, silver, lead, gold... up to a thickness of several centimeters. (A.C.)
[en] At Cadarache (southern France) the ITER consortium (International Thermonuclear Experimental Reactor) is building piece by piece what could become the very first prototype of tomorrow's power plant. The principle of ITER tokamak is the fusion of hydrogen atoms. This process, common in all stars of the universe, raises considerable scientific and technological challenges to be reproduced on the Earth's ground. If the first tests of ITER are favourable, this prototype will open up the way to the first fusion reactors by 2025, a decisive step towards abundant and clean energy
[en] Highlights: • No universal correlations between SUV and IVIM parameters were found in this study. • PET and IVIM histogram parameters can be used as independent potential biomarkers. • The 10th percentile of D performed better in distinguishing tumour grades. • Histogram-based lower diffusion and higher perfusion percentiles appear useful. Recommended articlesNo articles found.
[en] One of the benefits of regulatory dimensions of sustainability index value to improve the regulation of The Nuclear Power Plant development planning at the level of local government, as well as inputting of Long Term Development Plan Documents (RPJP) in Indonesia. The purpose of the study was to obtain a sustainability index value from the regulatory dimension in the framework of the plan to build NPP in Indonesia along with the industrial revolution 4.0. The study method uses Multi Dimensional Scaling (MDS) analysis by mapping perceptual mapping that relies on Euclidean Distance between one dimensions to the other dimensions. The results of the MDS analysis which included 16 regulations showed a sustainability index of the regulatory dimension of 42.89 (not yet sustainable). As a concrete step, RI Government Regulation No. 61 of 2013 concerning Management of Radioactive Waste with RMS 6.43, and Presidential Decree No. 106 of 2001 concerning Ratification of the Nuclear Safety Confession with RMS 6.18 eligible to be included in planning documents for provincial and regional levels. (author)
[en] Counterfeit and fraudulent items (CFls) are of increasing concern in the nuclear industry and generally throughout the industrial and commercial supply chains. Experience has shown that a lack of control of the processes involved in the sourcing, receipt, use and/or disposal of items can lead to the introduction of counterfeit or fraudulent items into a nuclear facility. This publication is designed to assist Member State organizations to prevent, detect and address CFIs on an ongoing basis. It provides users with recognized good practices for the introduction of a programme to effectively manage CFIs in the nuclear industry.