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.

Three-dimensional evaluation of maxillary sinuses in the Turkmen population, North of Iran

Introduction: Understanding the variation in the size and shape of the paranasal sinuses in detail is a clinically relevant matter for sinusitis patients. This study was performed to determine the right and left maxillary sinus dimensions by computed tomographic (CT) scan based on gender in the Turkmen ethnic groups in Gorgan, northern Iran. Material and Methods: In this descriptive-analytical study, 100 Turkmen subjects (50 males and 50 females) aged 18-45 were measured with 2 mm and 3 mm slices in the coronal and Axial Planes by the CT scanner SOMATOM Emotion of the multi-slice from the SIEMENS model and using the 'Syngo software Siemens.' Results: Maximum width, height, and volume of right and left maxillary sinuses in the Turkmen ethnic group were more in males than females (P < 0.05). In the right maxillary sinus; the mean maximum of width in males and females was 29.6 ± 4.91 mm and 26.53 ± 5.26 mm, respectively (P < 0.05). The mean maximum height in males and females was 40.5 ± 4.27 mm and 38.16 ± 5.96 mm, respectively (P < 0.05). In the left maxillary sinus, the mean maximum width in males and females was 29.61 ± 4.31 mm and 26.79 ± 5 mm, respectively (P < 0.05). The mean maximum height in males and females was 40.46 ± 4.55 mm and 38.03 ± 5.4 mm, respectively (P < 0.05). Discussion and Conclusion: Understanding the dimensions of the maxillary sinuses helps for better diagnosis and treatment of patients with maxillary sinuses diseases. © 2021 Journal of the Anatomical Society of India. All rights reserved

Coupled hydro-chemical-mechanical simulations of an engineered concrete barrier in a deep geological repository for nuclear waste

Decovalex 2023, Troyes, France, 14-16 November 2023.Deep geological disposal is extensively studied for the long-term containment of high-level nuclear waste. A disposal system should guarantee that the waste is not a hazard for the environment and remains isolated over long periods of time (millions or hundreds of thousands of years). Mined repositories are suitable to be implemented, as they rely on the multi-barrier concept to achieve the required degree of isolation. This study focuses on assessing the hydro-chemical-mechanical (HCM) behavior of cementitious materials, mainly used as liners or barrier systems, under repository conditions through the development of predictive models. The objective is to analyze the interaction between a support concrete structure and the surrounding clay rock in a deep waste-disposal facility. The elaborated methodology includes models for the hydro-mechanical (HM) response of materials and the hydro-chemical (HC) interaction at the concrete-rock interface, which will be later integrated into a coupled HCM model. The HM model is developed with the finite element method software CODE_BRIGHT and simulates the response of the concrete structure and surrounding rock. The two-dimensional plane-strain model consists of four stages: equilibration, simulating the excavation and alterations caused by drilling, constructing the support structure, and evaluating the long-term behavior of the system. Displacements, porosity variations and stress distributions are analyzed.The HC modeling focuses on the reactive transport modeling of the concrete-rock system. Retraso- CODE_BRIGHT is used to simulate the geochemical processes. The initial modeling stages considers a simplified one-dimensional system with a restricted number of mineral species involved in the concretesurrounding rock interaction. Data from earlier studies conducted at the Mont Terri Underground Rock Laboratory are used as the basis for the model, regarding the composition of concrete, the rock materials and pore-water compositions. The variation in pH, mineral precipitation/dissolution, volume fraction of minerals and concentrations of elements as a function of time and space are analyzed.The simulation time is 25 years. Preliminary HM results show a generalized compression state of stress, vertical y-displacements of 2 mm and horizontal x-displacements of 0.8 mm in the concrete structure. It is observed that porosity remains invariable because of the geomechanical effect. In the inner region of the lining, the failure limit is exceeded vertically. The excavation damage zone of the host rock extends 10 cm from the concrete-rock interface in the y-direction and 2 m away to the flanks in the x-direction. Preliminary HC results show significant dissolution of portlandite and calcium-silicate-hydrate (C-S-H) phases in the concrete-rock interface region. This results in an increase in the concrete porosity from 0.15 to a maximum value of 0.28 at the concrete-rock interface, and affects the concrete up to a distance of 1 cm from the interface. Future work will focus on determining an appropriate coupling method that integrates both models into an HCM model. Upscaling of concrete degradation with a correlation between porosity variations and changes in the Young’s modulus will be developed, ranging from the aggregate scale to continuum scale. In addition, model results will be compared with the experimental data obtained from the EURADMAGIC project.Peer reviewe

ydro-Chemo-Mechanical behaviour of cementitious materials from the aggregate to the continuum scale.

Peer reviewe

Hydro-Chemo-Mechanical behaviour of cementitious materials from the aggregate to the continuum scale.

Peer reviewe

Hydro-Chemo-Mechanical simulations of an engineered concrete barrier in a deep geological repository for nuclear waste

IDAEA Young Researchers’ Day, Barcelona, 14 December 2023.Deep geological disposal is extensively studied for the long-term containment of high-level nuclear waste, which relies on the multi-barrier concept to achieve the required degree of isolation. This study focuses on assessing the hydro-chemical-mechanical (HCM) behavior of a liner concrete structure under repository conditions through the development of predictive models. We include models for the hydro-mechanical (HM) response of materials and hydro-chemical (HC) interaction at the concrete-rock interface, which will be later integrated into a coupled HCM model. The HM model reveals that porosity changes are negligible due to HM loads, while the altered concrete may affect the liner integrity. The HC model shows that porosity changes are controled by portlandite and calcium-silicate-hidrate (CSH) dissolution and precipitation of a secondary CSH phase. The maximum increased porosity occurs near de interface, reaching 0.23. The length of geochemical affection is 3 cm, with increased porosity from 0.15 to 0.20.Peer reviewe

Development and Improvement of Numerical methods and Tools for Modelling Coupled Processes -State-of-the-Art

International audienceThe Strategic Research Agenda (SRA; https://www.ejp-eurad.eu/publications/eurad-sra) of the European Joint Programme on Radioactive Waste Management (EURAD; https://www.ejp-eurad.eu/) describes the scientific and technical domains and sub-domains and knowledge management needs of common interest between EURAD participant organizations.Theme number 7 is entitled "Performance assessment, safety case development and safety analyses". A list of research and development priorities and activities of common interest to be addressed within EURAD for theme 7 have been established. Amongst others, the Understanding and modelling of multi-physical Thermo-Hydro-Mechanical-Chemical coupled processes (THMC) occurring in radioactive waste disposal is a major and permanent issue to support optimization of design and safety case abstraction. To tackle this challenge a research work package entitled "DONUT : Development and improvement of numerical methods and tools for modelling coupled processes" has been conducted within the EURAD join programming initiative. The purpose of this work package is to improve/develop methods or numerical tools in order to go a step further in development of (i) relevant, performant and cutting-edge numerical methods that can easily be implemented in existing or new tools, in order to carry out high-performance computing to facilitate the study of highly coupled processes in large systems, (ii) numerical scale transition schemes for coupled processes, (iii) innovative numerical methods to carry out uncertainty and sensitivity analyses. In this paper the work carried out within the DONUT work package is put in perspective regarding the existing concept and literature on the field. It does not pretend to be exhaustive but rather to put emphasis on particular issues tackled during the project

State Of the Art Report in the fields of numerical analysis and scientific computing

This document provides an assessment of the current state-of-the-art for the DONUT work package. It is intended as a reference for the involved actors in EURAD and will be updated at the end of the project as new information becomes available. The prupose of this work package is to improve/develop methods or numerical tools in order to go a step further in development of (i) relevant, performant and cutting-edge numerical methods that can easily be implemented in existing or new tools, in order to carry out high-performance computing to facilitate the study of highly coupled processes in large systems. These methods and their implementation in tools will be mainly applied to reactive transport, 2-phase flow, and THM modelling in porous and fractured media; (ii) numerical scale transition schemes for coupled processes (meso1 to macro scale), supporting the study of specific multi-scale couplings such as chemo-mechanics; (iii) innovative numerical methods to carry out uncertainty and sensitivity analyses coupled processes.The readers have to keep in mind that this report is not reviewing all the existing codes, methods or tools that are available in the literature. It is rather written and oriented in the perspective of the research program that will be conducted by the different partners within DONUT. While some general statement are given, the research direction that will be followed by partners are outlined

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.