Nuclear Waste Disposal

Parallel MC Driver This area of work concerns models of radionuclide migration by taking into account the solid-liquid interaction phenomena through the migration process. It has investigated the groundwater transport of nuclides through a multilayer system in one and two dimensions, and has studied the effects of parameters and model assumptions on the predictions of the model. The model concentrates on those model assumptions that relate to the physico-chemical reactions between the liquid and solid phases. In order to weight the impact of different conceptual assumptions, a model has been implemented to describe the liquid phase-solid phase interaction. The uncertainties in model parameters and model assumptions have been investigated by a combination of Monte Carlo methodologies and Bayesian logic, which allows for uncertainty and sensitivity analysis. * * Here p(y * /θ s ,S,x) is the conditional predictive distribution for y * given specific choices for scenario, structure, and parameters, and p(θ s /S,x,D), p(S/x,D), and p(x/D) are posterior distributions for the parameters, structure, and scenario (respectively) given the past data. Each of these posterior distributions

We examine a conceptual framework for accounting for all sources of uncertainty in complex prediction problems, involving six ingredients: past data, future observables, and scenario, structural, parametric, and predictive uncertainty. We apply this framework to nuclear waste disposal using a computer simulation environment -GTNCHEN -which "deterministically" models the one-dimensional migration of radionuclides through the geosphere up to the biosphere. Focusing on scenario and parametric uncertainty, we show that mean predicted maximum doses to humans on the earth's surface due to 1-129, and uncertainty bands around those predictions, are larger when scenario uncertainty is properly assessed and propagated. We also illustrate the value of a new method for global sensitivity analysis of model output called extended FAST. @ 1999 Elsevier Science B.V.

Shales are among the most commonly considered geomaterials in current energy-related geomechanical investigations, as they are involved in engineering applications such as the extraction of natural gas, CO 2 sequestration and nuclear waste storage. A deep understanding of their behaviour with regard to variations in the degree of saturation is of significance for such applications. With the aim to establish a sound protocol for shale retention behaviour analysis, this paper presents an experimental methodology that takes into account the specificities of shales such as small pore size dimensions and the large variations in water potential to be applied to induce significant changes in the degree of saturation. The technique involves the direct control of the shale water content and the subsequent measurement of the suction at equilibrium by a psychrometer. A fluid displacement technique with a non-polar liquid is also used to assess the volume changes of the shale and to compute the degree of saturation. Selected test results are presented for various shale samples that have been cored at different depths. The results indicate that important features of the retention behaviour of geomaterials are fundamental aspects to be considered when analysing the retention behaviour of shales, such as the existence of main wetting and drying paths, the hysteresis domain, and the dependency of the air entry value on the void ratio.

Interaction between metal iron and a variety of natural and synthetic smectites samples with contrasting crystal chemistry was studied by scanning electron microscopy and X-ray diffraction (XRD) from experiments conducted at 80°C. These experiments demonstrate an important reactivity contrast as a function of smectite crystal chemistry. An XRD quantification method involving the use of an internal standard allowed quantification of the relative proportion of smectite destabilized as a function of initial pH conditions as well as of smectite structural parameters. In mildly acidic to neutral pH conditions, a significant proportion of metal iron is corroded to form magnetite without smectite destabilization. Under basic pH conditions, smectite and metal iron are partly destabilized to form magnetite and newly-formed 1:1 phyllosilicate phases (odinite and crondstedtite). Systematic destabilization of both metal iron and smectite is observed for dioctahedral smectites while trioctahedral smectites are essentially unaffected under similar experimental conditions. Smectite reactivity is enhanced with increasing Fe 3+ content and with the presence of Na + cations in smectite interlayers. A conceptual model for smectite destabilization is proposed. This model involves first the release of protons from smectite structure, MeFe 3+ OH groups being deprotonated preferentially and metal iron acting as proton acceptor. Corrosion of metal iron results from its interaction with these protons. Fe 2+ cations resulting from this corrosion process sorb on the edges of smectite particles and lead to induce the reduction of structural Fe 3+ and migrate into smectite interlayers to compensate for the increased layer charge deficit. Interlayer Fe 2+ cations subsequently migrate to the octahedral sheet of smectite because of the extremely large layer charge deficit. At low temperature, this migration is favored by the reaction time and by the absence of protons within the di-trigonal cavity. Smectite destabilization results from the inability of the tetrahedral sheets to accommodate the larger dimensions of the newly formed trioctahedral domains resulting from the migration of Fe 2+ cations. 46

Trends and opportunities for the radioactive waste disposal in the Earth crust This paper deals with the problems of designing and realization of permanent disposal sites for nuclear wastes. It points out the possibilities of the development of new and modern technologies of drilling, mining, or driving of underground works. The paper is primarily aimed at the cuttingof the period of storage building, the reaching of larger depths, the reduction of territory of storage area as well as the increase of its safety.

This paper presents numerical modeling of coupled thermal, hydraulic and mechanical processes in rock salt and crushed salt considering halite solubility constraints. The TOUGH-FLAC simulator is used, with a recently enhanced Equation-Of-State module that includes the thermodynamic properties of aqueous fluids of variable salinity. Laboratory and field scale tests performed on rock salt and crushed salt under temperature gradients are modeled first to evaluate the capabilities of the simulator to reproduce important features, such as porosity changes induced by halite dissolution/precipitation, and brine and heat migration. Since the results are quite satisfactory, the simulator is used to predict the long-term response of a generic salt repository for heat-generating nuclear waste. To evaluate the impacts of halite solubility on the predictions, two simulations that respectively consider or neglect solubility constraints are performed. In the scenario studied, the results are not significantly affected by dissolution/precipitation, and only some differences are observed due to changes in porosity, but the dominating processes remain the same. With the new provisions, TOUGH-FLAC is more complete in terms of processes occurring around a heat-releasing nuclear waste package and can therefore provide more accurate predictions of the long-term performance of a nuclear waste repository in salt formations.

The Cementitious Barriers Partnership (CBP) was initiated to reduce risk and uncertainties in the performance assessments that directly impact U.S. Department of Energy (DOE) environmental cleanup and closure programs. The CBP is supported by the DOE Office of Environmental Management (DOE-EM) and has been specifically addressing the following critical EM program needs: (i) the long-term performance of cementitious barriers and materials in nuclear waste disposal facilities and (ii) increased understanding of contaminant transport behavior within cementitious barrier systems to support the development and deployment of adequate closure technologies. To accomplish this, the CBP has two initiatives: 1) an experimental initiative to increase understanding of changes in cementitious materials over long times (> 1000 years) over changing conditions and 2) a modeling initiative to enhance and integrate a set of computational tools validated by laboratory and field experimental data to improve understanding and prediction of the long-term performance of cementitious barriers and waste forms used in nuclear applications. In FY10, the CBP developed the initial phase of an integrated modeling tool that would serve as a screening tool which could help in making decisions concerning disposal and tank closure. The CBP experimental programs are underway to validate this tool and provide increased understanding of how CM changes over time and under changing conditions. These initial CBP products that will eventually be enhanced are anticipated to reduce the uncertainties of current methodologies for assessing cementitious barrier performance and increase the consistency and transparency of the DOE assessment process. These tools have application to low activity waste forms, high level waste tank closure, D&D and entombment of major nuclear facilities, landfill waste acceptance criteria, and in-situ grouting and immobilization of vadose zone contamination. This paper summarizes the recent work provided by the CBP to support DOE operations and regulatory compliance and the accomplishments over the past 2 years. Impacts of this work include: 1) a forum for DOE-NRC technical exchange, 2) material characterization to support PA predictions, 3) reducing uncertainty in PA predictions, 4) establishing base case performance to improve PA predictions, and 5) improving understanding and quantification of moisture and contaminant transport used in PAs. Additional CBP accomplishments include: sponsorship of a national test bed workshop to obtain collaboration in establishing the path forward in obtaining actual data to support future predictions on cementitious barrier performance evaluations, and participation in an International Atomic Energy Agency (IAEA) Cooperative Research Project on the use of cementitious barriers for low-level radioactive waste treatment and disposal.

BACCHUS2 in situ isothermal wetting experiment has been analysed by means of a coupled flowdeformation approach. Backfill material, a mixture of Boom clay powder and high density pellets, has been extensively tested in the laboratory in order to determine its hydraulic and mechanical properties. Parameters of constitutive equations were derived from this experimental data base. Two mechanical constitutive models have been used in the simulation of the 'in situ' experiment: a state surface approach and an elastoplastic model. Calculations have shown several features of the hydration process which help to understand the behaviour of expansive clay barriers. Predictions using both models have been compared with each other and with actual measurement records. This has allowed a discussion of the comparative mertis of both approaches and the identification of some critical parameters of backfill behaviour. Overall agreement between calculations and field measurements is encouraging and shows the potential of the methods developed to model the behaviour of engineered clay barriers in the context of nuclear waste disposal.

This paper focuses on reconfiguring manufacturing capabilities by aligning know-how and customer focus capabilities in finding manufacturing capabilities mechanism. The methodology applies Newsboy problem to capability transformation and game theory to capture bigger market share. Further, response analysis finds reconfiguration response pattern. The results show that a firm manufacturing strategy should consider know-how and customer focus on their manufacturing capability transformation to get information related to product life cycle and costs of technology and opportunity lost. The proposed approach shows that combination among Newsboy vendor problem, game theory and system dynamic models is suitable to be applied in maintaining the firm competitiveness. An innovated model of 'Newsboy vendor-game theory-system dynamic' shows the novelty of this proposed methodology.

Choosing a project for which benets accrue to all involved agents but brings major costs or additional benets to only one agent is often problematic. Siting a nationwide nuclear waste disposal or hosting a major sporting event are examples of such a problem: costs or benets are tied to the identity of the host of the project. Our goals are twofold: to choose the ecient site (the host with the lowest cost or the highest localized surplus) and to share the cost, or surplus, in a predetermined way so as to achieve redistributive goals. We propose a simple mechanism to implement both objectives. The unique subgame-perfect Nash equilibrium of our mechanism coincides with truthtelling, is ecient, budgetbalanced and immune to coalitional deviations. * HEC Montréal, Institut d'Économie Appliquée and CIRPÉE. † We are grateful for stimulating conversations with Francis Bloch, Lars Ehlers, Hervé Moulin, Nicolas Sahuguet and Bernard Sinclair-Desgagné as well as for feedback from participants of the Montreal Natural Resources and Environmental Economics Workshops and the Economics Workshop of HEC Montréal.

The Brazilian (indirect tensile strength) test is widely adopted for studying the permeability evolution of single localized macro-cracks in concrete samples. In most of these studies, the existence of a threshold crack opening effect on the crack permeability is argued, in particular when permeability measurements are performed on previously cracked samples (i.e., on residual cracks). Based on recent experimental results obtained by Authors, the present contribution aims to show that performing permeability measurements in real-time with the crack opening process (i.e., under loading) ensures improving the results quality and makes their interpretation less ambiguous. It is shown that no threshold crack opening effect is detected in the explored range of crack opening displacement. Although presented results do not allow to conclude concerning the existence of such an effect, they point out several critical aspects concerning the interpretations usually provided. In particular, based on the comparison between present and reference results, it is proposed to interpret literature observations as a direct consequence of some artifacts inherent to standard experimental procedures, such as the impossibility of distinguishing between crack and porous medium contributions to the measured mass flow rate, crack re-closure due to unloading and/or self-healing phenomena, an inaccurate estimation of the crack opening displacement corresponding to flow measurements.

Meso-crack evolution mechanism of shale is a key factor affecting the mechanical properties of shale. In order to explore evolution laws of cracks in shale during loading, a meso-crack monitoring system, loading test equipment and an automatic ultrasonic data acquisition system were set up. On this basis, a set of experimental apparatus simultaneous monitoring multi-parameters of shale micro-crack was designed, and destruction experiments of shale samples with different bedding angles were carried out to find out evolution characteristics of cracks. The results show the following: (1) The designed apparatus can monitor ultrasonic, mechanical and video information simultaneously of crack evolution in the entire process of shale destruction under load to provide information for analyzing acoustic and mechanical characteristic responses of crack propagation at key time nodes. (2) With an increase in load, shale will undergo four stages of destruction: crack initiation, propagation, pen...

In the context of deep geological disposal of high level radioactive wastes, the French National Radioactive Waste Management Agency (Andra) has conducted an extensive characterization of the Callovo-Oxfordian argillaceous rock and surrounding formations in the Eastern Paris Basin. For such characterization, a detailed 3D geological model is needed. This paper shows the procedure used for building the 3D model with depth by combining time-to-depth conversion of seismic horizons, consistent seismic velocity model and elastic impedance in time. It also shows how the 3D model is used for mechanical and hydrogeological studies. The 3D field data example illustrates the potential of the proposed depth conversion procedure for estimating a density model with depth. The geological model shows good agreement with logging data obtained at a reference well, a closest borehole located in the vicinity of the 3D seismic area. Modeling of mechanical parameters such as shear modulus, young modulus, bulk modulus indicates weak variability of these parameters which confirm the homogeneity of the Callovo-Oxfordian clay. 3D modeling of a permeability index (Ik-Seis) computed from seismic attributes (instantaneous frequency, envelope, elastic impedance) and validated at the reference borehole shows promising potential for supporting hydrogeological simulation.

The use of deep boreholes for the disposal of high level radioactive waste is reassessed, emphasizing key enabling technical features and their strong linkage to national and international fuel cycle policy. Emplacement 2 to 4 km deep in widely available granitic continental bedrock, under a 1 km caprock layer of high-integrity bedrock, is shown in this analysis to have the potential to provide sufficiently low host rock permeability to prevent radionuclide escape by transport in waterthe only plausible release mechanism. The modular nature of the concept enables multi-region siting in large user countries, and is especially well-suited for small-user nations. Irretrievability can be built-in to better meet safeguards objectives, and the exceptionally high assurance of confinement makes minor actinide (and troublesome fission product) disposal an attractive alternative to their destruction by transmutation.

D4.15 i Fate of repository gases (FORGE) The multiple barrier concept is the cornerstone of all proposed schemes for underground disposal of radioactive wastes. The concept invokes a series of barriers, both engineered and natural, between the waste and the surface. Achieving this concept is the primary objective of all disposal programmes, from site appraisal and characterisation to repository design and construction. However, the performance of the repository as a whole (waste, buffer, engineering disturbed zone, host rock), and in particular its gas transport properties, are still poorly understood. Issues still to be adequately examined that relate to understanding basic processes include: dilational versus viscocapillary flow mechanisms; long-term integrity of seals, in particular gas flow along contacts; role of the EDZ as a conduit for preferential flow; laboratory to field up-scaling. Understanding gas generation and migration is thus vital in the quantitative assessment of repositories and is the focus of the research in this integrated, multi-disciplinary project. The FORGE project is a pan-European project with links to international radioactive waste management organisations, regulators and academia, specifically designed to tackle the key research issues associated with the generation and movement of repository gasses. Of particular importance are the longterm performance of bentonite buffers, plastic clays, indurated mudrocks and crystalline formations. Further experimental data are required to reduce uncertainty relating to the quantitative treatment of gas in performance assessment. FORGE will address these issues through a series of laboratory and field-scale experiments, including the development of new methods for up-scaling allowing the optimisation of concepts through detailed scenario analysis. The FORGE partners are committed to training and CPD through a broad portfolio of training opportunities and initiatives which form a significant part of the project. Further details on the FORGE project and its outcomes can be accessed at www.FORGEproject.org.

Approaches to model the behaviour of underground disposals for nuclear waste have traditionally assumed perfect contacts between the different materials. However interfaces between the materials may affect significantly the hydration process of the bentonite buffer and later act as preferential pathways for the migration of radionuclides. The paper presents an approach to model interfaces using contact finite elements. The influence of interfaces on the hydration kinetics of a bentonite buffer is highlighted.

The Boom Clay is considered as one of the potential host rock formation in Belgium for radioactive waste repository in deep geological layers. Gallery excavations will induce large hydro-mechanical disturbances around disposal system that need to be well understood and characterised. This study discusses particularly the role of interactions between the lining of the galleries and the host formation in the numerical characterisation of excavations in Boom Clay. The excavation and the convergence of the connecting gallery of the HADES underground research facility in Mol is modelled in a hydromechanical framework. Zero-thickness interface elements are used to manage numerically the contact between the host rock and the lining. Numerical predictions are compared with strains measurements recorded within the concrete segments of the lining in the underground research laboratory in Mol. The study highlights the impact of the anisotropic behavior of the host rock on the response of the model.

Galleries drilling leads to damage propagation, fracturing and properties modifications in the surrounding medium. The prediction of the damaged zone behaviour is an important matter and needs to be properly assessed. To do so the fractures can be modelled using shear strain localisation. The coupled local second gradient model is used under unsaturated conditions to correctly model the strain localisation behaviour. The permeability evolution and the rock desaturation due to air ventilation in galleries are considered. Finally, a hydro-mechanical modelling of a gallery excavation in Callovo-Oxfordian claystone is performed leading to a fairly good representation of the damaged zone.

Approaches to model the behaviour of underground disposals for nuclear waste have traditionally assumed perfect contacts between the different materials. However interfaces between the materials may affect significantly the hydration process of the bentonite buffer and later act as preferential pathways for the migration of radionuclides. The paper presents an approach to model interfaces using contact finite elements. The influence of interfaces on the hydration kinetics of a bentonite buffer is highlighted.

Tunnel excavations in deep rocks provide stress perturbations which initiate diffuse and/or localized damage propagation in the material. This damage phenomenon can lead to significant irreversible deformations and changes in rock properties. In this paper, we propose to model such behavior by considering a micromechanically-based damage approach. The resulting micromechanical model, which also accounts for initial stress, is described and assessed through the numerical analysis of a synthetic tunnel drilling in Opalinus Clay. A particular emphasis is put on the numerical integration of the model. In particular, an appropriate choice of the latter is required to ensure the numerical stability and a confident prediction of excavation damaged zone around tunnels.

The formation of an Excavation Damage Zone (EDZ) is a phenomenon that occurs in the most rock masses as a consequence of underground excavation. The EDZ appears as an area around the underground openings, where geotechnical and hydro-geological properties are altered. The purpose of this paper is the development of a hydro-mechanical model able to reproduce the evolution of permeability during the lifetime of the underground radioactive waste storage. Indeed, in order to propose a design of the geo-structure, the numerical models have to tackle the relevant processes and to predict the behavior of the engineered barrier system. The evolution of the permeability within the EDZ can be directly associated to strain localization or damage . When a rock is damaged, crack networks are created, which constitute preferential flow paths. As a consequence, the rock hydraulic conductivity increases and generally becomes anisotropic . The permeability of crack is usually related to the crack aperture and the key issue is thus to propose a model providing the relationship between rock mass permeability and crack aperture, as well as the evolution of the crack aperture during the excavation. Different approaches exist to tackle this problem, from micro-macro theories to macroscopic (phenomenological) ones . In this paper, we use the latter theories to relate the aperture evolution to the strain tensor . As a starting point of our development, we describe first, in section 2, a long term dilatometer experiment, performed in Mont Terri Rock Laboratory in the context of radioactive waste storage studies. The dilatometer is supposed to sham the bentonite swelling

D4.15 i Fate of repository gases (FORGE) The multiple barrier concept is the cornerstone of all proposed schemes for underground disposal of radioactive wastes. The concept invokes a series of barriers, both engineered and natural, between the waste and the surface. Achieving this concept is the primary objective of all disposal programmes, from site appraisal and characterisation to repository design and construction. However, the performance of the repository as a whole (waste, buffer, engineering disturbed zone, host rock), and in particular its gas transport properties, are still poorly understood. Issues still to be adequately examined that relate to understanding basic processes include: dilational versus viscocapillary flow mechanisms; long-term integrity of seals, in particular gas flow along contacts; role of the EDZ as a conduit for preferential flow; laboratory to field up-scaling. Understanding gas generation and migration is thus vital in the quantitative assessment of repositories and is the focus of the research in this integrated, multi-disciplinary project. The FORGE project is a pan-European project with links to international radioactive waste management organisations, regulators and academia, specifically designed to tackle the key research issues associated with the generation and movement of repository gasses. Of particular importance are the longterm performance of bentonite buffers, plastic clays, indurated mudrocks and crystalline formations. Further experimental data are required to reduce uncertainty relating to the quantitative treatment of gas in performance assessment. FORGE will address these issues through a series of laboratory and field-scale experiments, including the development of new methods for up-scaling allowing the optimisation of concepts through detailed scenario analysis. The FORGE partners are committed to training and CPD through a broad portfolio of training opportunities and initiatives which form a significant part of the project. Further details on the FORGE project and its outcomes can be accessed at www.FORGEproject.org.

D13 9/103 Dissemination level: PU Date of issue of this report: 31/08/10 Geomechanical characteristics Case A Case B Cases C and D Young elastic modulus [MPa] E0 300 300 300 Poisson ratio [-] υ 0.125 0.125 0.125 Specific mass [kg/m³] ρ 2682 2682 2682 Initial cohesion [kPa] c0 300 300 300 Final cohesion [kPa] cf 300 300 100 Softening parameter [-] c

Slow future changes in astronomic phenomena seem to make it likely that Finland nil suffer several cold periods during the next 100,000 years. The paper analyses the characteristics of the periglacial factors that are most likely to influence the long-term safety of high-level radioactive waste disposed of in bedrock. These factors and their influences have been divided into two categories, natural and human. It is concluded that the basically natural phenomena are theoretically better understood than the complicated phenomena caused by man. It is therefore important in future research into periglacial phenomena, as well as of the disposal problem, to emphasize not only the proper applications of the results of natural sciences, but especially the effects and control of mankind's own present and future activities.

I have adapted the nuclear materials storage location to align with mudstone bedrock for either or both above or below sea level tunnels.

Please find a revised scheme to locate a nuclear material storage scheme in mudstone bedrock with the option for both above and below sea level tunnels.

A trial proving tunnel is included to enable characterization to be determined to address risks and experiences tunnelling in the area.

It has significant capacity and can be constructed in stages.
Cumbria Nuclear Material Storage Scheme Constructed in Mudstone Bedrock Proposal
Considering the UK Government has a preference for installing the Nuclear Material Storage tunnels in Mudstone Bedrock the following location is an alternative to locating the work site further from Millom.  The selected area enables the tunnels to be either above sea level or below sea level.  The proposed scheme provides both above and below sea level tunnels to be constructed for the different performances to be assessed.
Each level within the mudstone material area can accommodate up to 11 tunnels each 60 metres apart.  This will enable up to 100 Km of tunnel per level.
The location is suitable for locating a jetty for import of TBMs and materials and export of removed crushed bedrock.
The proposed scheme includes a proving tunnel to enable the characteristics of the sites to be evaluated.  This tunnel will be used to test the logistics, storage methods and trial the equipment and machines required for operating the storage facilities.
The providing tunnel will enable the ground and bedrock and below sea level water movement characteristics and management to be evaluated.
The following images are:
Image 1 Image 1 Proposed Scheme location enabling the construction of on land and offshore tunnels in Mudstone
Image 2 Location of Portals and Storage Footprint
Image 3 Proposed 250m Contour Area
Image 4 Black Combe and Fell Grey Mudstone Area

The EURATOM 7 th EC Framework Program Collaborative Project REdox phenomena Controlling SYstems (RECOSY) started in April 2008 and extends over 4 years. Although redox is not a new geochemical issue, different questions are still not resolved. For this reason, main objectives of RECOSY project are a) the sound understanding of redox phenomena controlling the long-term release/retention of radionuclides in nuclear waste disposal, b) providing tools to apply the result to Performance Assessment/Safety Case, c) training of next generation and d) documentation and communication of the results. To this aim, the project set up a consortium of 32 Beneficiaries/Contractors and presently 6 Associated Groups. The consortium includes key European Research Institutes, Universities, National Waste Management Agencies and SMEs, from 13 EURATOM signatory states, Russia, Japan, Korea, USA and one European Joint Research Centre. The ReCosy concept is innovative in the scientific approach to the redox phenomena. It includes i) advanced analytical tools, ii) investigations of processes responsible for redox control (thermodynamically and kinetically controlled processes, surface reactions and microbial processes,...), iii) provision of required data on redox controlling processes, and iv) response to disturbances in disposal systems. The work program is structured along six RTD workpackages (WP1-6). They cover near-field and far field aspects as well as all relevant host-rocks considered in Europe. In WP1, the scientific state-of-theart and its application to Performance Assessment/Safety Case is documented and regularly up-dated. WP2 focuses on development of redox determination methods. WP3 focuses on redox response of defined and near-natural systems. WP4 studies the redox reactions of radionuclides. WP5 focuses on Redox processes in radionuclide transport and WP6 deals with redox reactions affecting the spent fuel source-term. Specific workpackages on knowledge management, education and training (WP7) and administrative management issues (WP8) are also included in the project The present proceedings document the outcome of the 3 rd Annual Project Workshop and give an overview of the outcome of the 3 rd project year.

Understanding the thermodynamics of multi-principal element alloys (MPEA), also known as high entropy alloys (HEA) is crucial to addressing their synthesis, properties, stability, materials compatibility, and technological applications. While the thermodynamics of binary and ternary alloys are relatively well investigated both experimentally and theoretically in the last five decades, this is not the case for multicomponent (>4 elements) alloys. The classical calorimetric methods (e.g., liquid metal bath, direct reaction, and flux calorimeter) used for binary and trinary alloys will often encounter difficulties for alloys with more than three elements. Thus, a more flexible and general calorimetric approach is needed. The present work introduces a new methodology for measuring the enthalpy of formation from elements of metals based on high-temperature oxidative calorimetry. This technique is based on the well-developed oxide melt solution calorimetry (OMSC). Using this method, the heats of formation of four binary (AlNi, AlFe, AlCo, and AlFe 3 ), four quaternary CrFeCoNi, AlCrCoNi, AlFeCoNi, AlCrFeCo and four quinary, AlCrFeCoNi, Al 0.3 CrFeCoNi, CrMnFeCoNi and AlTiVNbTa alloys were obtained. The values in kJ/(mol atom

Understanding the thermodynamics of multi-principal element alloys (MPEA), also known as high entropy alloys (HEA) is crucial to addressing their synthesis, properties, stability, materials compatibility, and technological applications. While the thermodynamics of binary and ternary alloys are relatively well investigated both experimentally and theoretically in the last five decades, this is not the case for multicomponent (>4 elements) alloys. The classical calorimetric methods (e.g., liquid metal bath, direct reaction, and flux calorimeter) used for binary and trinary alloys will often encounter difficulties for alloys with more than three elements. Thus, a more flexible and general calorimetric approach is needed. The present work introduces a new methodology for measuring the enthalpy of formation from elements of metals based on high-temperature oxidative calorimetry. This technique is based on the well-developed oxide melt solution calorimetry (OMSC). Using this method, the heats of formation of four binary (AlNi, AlFe, AlCo, and AlFe 3 ), four quaternary CrFeCoNi, AlCrCoNi, AlFeCoNi, AlCrFeCo and four quinary, AlCrFeCoNi, Al 0.3 CrFeCoNi, CrMnFeCoNi and AlTiVNbTa alloys were obtained. The values in kJ/(mol atom

**Abstract für das erste Jahr unseres Kalenders**

Dieser Artikel präsentiert die Einführung "UNSERES NEUEN KALENDERS der NEUEN ZEITRECHNUNG", der am 1. April 2025 beginnt und eine bahnbrechende Neugestaltung unserer Zeitrechnung darstellt. Der Kalender basiert auf einer einzigartigen Struktur aus 13 Monaten mit jeweils 28 Tagen, was zu einem Gesamtjahr von 364 Tagen führt. Durch diese innovative Zeitrechnung wird eine tiefere Verbindung zur natürlichen Welt und den kulturellen Rhythmen gefördert.

Im ersten Jahr werden die Monate, Wochentage und die spezifischen Mondphasen (Neumond und Vollmond) detailliert dargestellt, um eine klare und präzise Zeitplanung zu ermöglichen. Darüber hinaus beleuchtet das Dokument die besonderen Merkmale des neuen Kalenders, wie den symbolischen Schuldenerlass am Ende des Göttermonats und die Rückkehr zur verlorenen Zeit.

Der Artikel schließt mit einem Aufruf zur Reflexion über die Beziehung von Mensch und Natur sowie der Bedeutung von Zeit für unser gemeinsames Leben. UNSER NEUER KALENDER zielt darauf ab, eine harmonische und nachhaltige Lebensweise zu fördern und lädt Leser und Interessierte ein, sich aktiv mit der neuen Zeitrechnung auseinanderzusetzen.

Al giorno d’oggi l’espressione “odontoiatria estetica” risulta quasi ridondante, il concetto di estetica è diventato, infatti, intrinseco ed imprescindibile da tale disciplina medica. In un contesto sociale in cui il paziente che “si accontenta” di un risultato accettabile si sta riducendo ed in cui la formazione dell’odontoiatra mira ad attivare competenze e tecniche altamente performanti, questo lavoro si prefigge l’obiettivo di sfruttare quelli che sono i punti di forza di un sistema estetico per sopperire a problematiche di tipo funzionale. I disordini temporo-mandibolari (DTM) sono un insieme di patologie che interessano le articolazioni temporo-mandibolari (ATM), la muscolatura masticatoria e le strutture connesse e che influiscono sulla funzionalità dell’apparato stomatognatico. La terapia di elezione per tali disturbi è costituita da dispositivi mobili (bite) che hanno come prerogativa il ricreare la stabilità a livello articolare, ma che, per i loro limiti di costruzione, r...

The Cs selectivity of several natural zeolitic tufts and synthetic zeolites was measured. Phillipsite-rich tufts from California and Nevada exchanged 13.5 and 23.7%, respectively, of the Cs present in simulated alkaline defense waste containing 0.00025 M CsCl in 5.5 M NaC1-NaOH solution from the Savannah River Plant, Aiken, South Carolina; whereas mordenite-rich tufts from Arizona and Nevada exchanged less than 12.7%. The immobilization or fixation of Cs in phillipsite unlike other zeolites can be achieved by heating the zeolite at 600~ for 4 hr in air and collapsing the silicate (aluminate) tetrahedral tings around the Cs ions to produce a Cs-feldspar-type phase. Treatment of the Cs-exchanged phillipsiterich tuft at 800 ~ to 1000~ resulted in pollucite, CsA1Si206, which also "locks in" the Cs ions in its structure. The fixation of Cs exchanged in phillipsite can also be achieved by the formation of pollucite upon hydrothermal treatment at 300~ and 30 MPa pressure within 12 hr. These results suggest that phillipsite-rich tufts are good candidates for Cs immobilization by heat treatment at low temperatures after they have been used as sorbents in waste decontamination.

Defect production in energetic collision cascades in zircon has been studied by molecular dynamics simulation using a partial charge model combined with the Ziegler-Biersack-Littmark potential. Energy dissipation, defect accumulation, Si-O-Si polymerization and Zr coordination number were examined for 10 keV and 30 keV U recoils simulated in the constant NVE ensemble. For both energies an amorphous core was produced with features similar to that of melt quenched zircon. Disordered Si ions in this core were polymerized with an average degree of polymerization of 1.5, while disordered Zr ions showed a coordination number of about 6 in agreement with EXAFS results. These results suggest that nano-scale phase separation into silica-and zirconia-rich regions occurs in the amorphous core.

Defect production in energetic collision cascades in zircon has been studied by molecular dynamics simulation using a partial charge model combined with the Ziegler-Biersack-Littmark potential. Energy dissipation, defect accumulation, Si-O-Si polymerization and Zr coordination number were examined for 10 keV and 30 keV U recoils simulated in the constant NVE ensemble. For both energies an amorphous core was produced with features similar to that of melt quenched zircon. Disordered Si ions in this core were polymerized with an average degree of polymerization of 1.5, while disordered Zr ions showed a coordination number of about 6 in agreement with EXAFS results. These results suggest that nano-scale phase separation into silica-and zirconia-rich regions occurs in the amorphous core.

From the perspective of a human lifetime, the hazards of some nuclear wastes are permanent, so the warnings we place at contaminated nuclear sites must be permanent too. I address questions of how best to provide one hundred centuries of public warning at the first facility for permanent disposal, the Waste Isolation Pilot Plant in New Mexico. Scenarios of intrusion developed to guide the design of warning markers predicted that most of the changes in the area will be social and cultural. Because blatant and permanent markers will increase, not reduce, the probability of inadvertent intrusion, the most appropriate warning is a "landscape of illusion." Such a landscape needs not permanent surface markers but underground warning devices beneath a soft surface marker. No warnng can guarantee deterrence for lo,ooo years, however.

It is possible in answer to construct a Swedish style configuration in the white area in South Copeland in the mudstone bedrock at same depth as Sweden proposes of-500m below sea level with an additional 200m of top cover, or in the footprint of the igneous rock. These are dependent upon South Copeland and Cumbria consent and the geological/hydrological assessments. These open up the options for different nuclear material storage facilities to be assessed. The white mudstone area is 5Km by 4Km. The second image below is copyright of SKB and World Nuclear News World Nuclear News The Swedish government and SKB unveil a roadmap which envisages the construction of new nuclear generating capacity equivalent to at least two large-scale reactors by 2035, with up to ten new large-scale reactors coming online.

The results of a 21 month sampling program measuring tritium in tree transpirate with respect to local sources are reported. The aim was to assess the potential of tree transpirate to indicate the presence of sub-surface seepage plumes. Transpirate gathered from trees near low-level nuclear waste disposal trenches contained activity concentrations of 3 H that were significantly higher (up to w700 Bq L À1 ) than local background levels (0e10 Bq L À1 ). The effects of the waste source declined rapidly with distance to be at background levels within 10s of metres. A research reactor 1.6 km south of the site contributed significant (p < 0.01) local fallout 3 H but its influence did not reach as far as the disposal trenches. The elevated 3 H levels in transpirate were, however, substantially lower than groundwater concentrations measured across the site (ranging from 0 to 91% with a median of 2%). Temporal patterns of tree transpirate 3 H, together with local meteorological observations, indicate that soil water within the active root zones comprised a mixture of seepage and rainfall infiltration. The degree of mixing was variable given that the soil water activity concentrations were heterogeneous at a scale equivalent to the effective rooting volume of the trees. In addition, water taken up by roots was not well mixed within the trees. Based on correlation modelling, net rainfall less evaporation (a surrogate for infiltration) over a period of from 2 to 3 weeks prior to sampling seems to be the optimum predictor of transpirate 3 H variability for any sampled tree at this site. The results demonstrate successful use of 3 H in transpirate from trees to indicate the presence and general extent of sub-surface contamination at a low-level nuclear waste site.

Matrix diffusion is an important mechanism for solute transport in fractured rock. We recently conducted a literature survey on the effective matrix diffusion coefficient, , a key parameter for describing matrix diffusion processes at the field scale. Forty field tracer tests at 15 fractured geologic sites were surveyed and selected for study, based on data availability and quality. Field-scale values were calculated, either directly using data reported in the literature or by reanalyzing the corresponding field tracer tests. Surveyed data indicate that the effective-matrix-diffusion-coefficient factor e m D e m D D F (defined as the ratio of to the lab-scale matrix diffusion coefficient [ ] of the same tracer) is generally larger than one, indicating that the effective matrix diffusion coefficient in the field is comparatively larger than the matrix diffusion coefficient at the rock-core scale. This larger value could be attributed to the many mass-transfer processes at different scales in naturally heterogeneous, fractured rock systems. Furthermore, we observed a moderate trend toward systematic increase in the e m D m D D F value with observation scale, indicating that the effective matrix diffusion coefficient is likely to be statistically scale dependent. The D F value ranges from 1 to 10,000 for observation scales from 5 to 2,000 m. At a given scale, the D F value varies by two orders of magnitude, reflecting the influence of differing degrees of fractured rock heterogeneity at different sites. In addition, the surveyed data indicate that field-scale longitudinal dispersivity generally increases with observation scale, which is consistent with previous studies. The scaledependent field-scale matrix diffusion coefficient (and dispersivity) may have significant implications for assessing long-term, large-scale radionuclide and contaminant transport events in fractured rock, both for nuclear waste disposal and contaminant remediation.

Groundwaters from the Tithonian/Kimmeridgian, Oxfordian and Upper Dogger aquifers, within the eastern part of the Paris basin (France), were characterised using 3 H, 14 C and 36 Cl, and noble gases tracers, to evaluate their residence times and determine their recharge period. This information is an important prerequisite to evaluating the confinement properties of the Callovo-Oxfordian clay formation sandwiched between the Oxfordian aquifer and the Dogger aquifer, currently being investigated by the French nuclear waste management agency (Andra) for radioactive waste disposal. Data presented in this paper are used to test 4 hypotheses. (1) The Oxfordian limestone is isolated from the overlying Tithonian/Kimmeridgian surface aquifer. This first hypothesis is supported by the presence of measurable 3 H activities in groundwaters from the surface aquifer (6-11 TU), and by its absence in groundwaters derived from deeper aquifers (<3 TU), as well as by geochemical data from earlier studies. (2) The Callovo-Oxfordian clay sequence in the vicinity of the URL serves as an effective barrier to advective flow and transport between the underlying Upper Dogger aquifer and the overlying Oxfordian limestone aquifer. This second hypothesis is supported by relatively low concentrations of Cl (3.5-78 mg L À1 ), Na (15-145 mg L À1 ), Br (0.08-0.4 mg L À1 ) and 4 He rad (0.2-2.3 ccSTP g À1 ) and slightly higher 36 Cl/Cl ratios (2.7-59 Â 10 À15 at at À1 ) in groundwaters from the Oxfordian aquifer, compared to those from the Upper Dogger aquifer (345-4027 mgCl L À1 ; 402-2390 mgNa L À1 , 1.8-22.2 mgBr L À1 , 1.6-37.2 ccSTP He g À1 , 1-5 Â 10 À15 at 36 Cl at À1 Cl). (3) Groundwaters from the Oxfordian aquifer, in the vicinity of URL are pre-Holocene, with residence times exceeding 10 ka. Geochemical and isotopic lines of evidence for this hypothesis include: (a) d 13 C values measured on Oxfordian aquifer waters that are close to d 13 C of the aquifer matrix, reflecting strong isotopic exchange over several thousand years; (b) noble-gas temperatures that indicate recharge temperatures between 3 and 8.6 °C, lower by 2-7 °C than the modern average temperature in this area; (c) radiogenic 4 He concentrations between 0.16 Â 10 À5 and 2.3 Â 10 À5 ccSTP g À1 of water, about 2-3 orders of magnitude greater than the 4 He concentration of air-equilibrated water. (4) Groundwater residence time for the Upper Dogger aquifer in the vicinity of the URL probably exceed several hundred thousand years. Such long residence times are indicated by the accumulation of radiogenic He-up to 37 Â 10 À5 ccSTP g À1 assuming a closed system.

Jabal Huliat Al-Gran (HG) volcano is one of several volcanic eruptions belonging to south Jordanian basaltic eruptions. Thick pyroclastic deposits of volcanic tuff layers alter slowly to complex mineralogical zonations in closed hydrological alkaline environments, and relatively pure deposits can be formed. Hydrological system and temperature are the principal controls over the zeolitization process. This process involves reactions between the vitric silicic volcanic glass and the percolating water in a closed hydrological system to form distinctive zeolite assemblages. Judging from field and experimental data, formation of phillipsite, chabazite and other secondary rock forming minerals probably took place by reaction of percolating water with vitric tuff units. The petrographical, mineralogical and geochemical investigations include thin section, XRD and SEM-EDX to determine the nature, geneses, along with mineralogical and geochemical properties of this new zeolitic occurrence. T...

Deep geological disposal in suitable host rocks is the favoured strategy for the storage and disposal of heat-emitting high level nuclear waste. A rational design of repositories requires a good understanding of the interacting thermo-hydro-mechanical phenomena that occur in the engineered barrier and adjacent rock. To this end, a multiphysical formulation is described that allows the performance of coupled THM analyses capable of reproducing observed phenomena. The formulation and computer code is applied to the simulation of two large scale tests: a mine-by test involving the excavation of a shaft in an argillaceous rock and a large-scale high-temperature heating test in fractured rock. RÉSUMÉ: La stratégie préconisée actuellement pour le stockage et le dépôt de déchets de haute radioactivité émettant de la chaleur est de les disposer dans des couches géologiques profondes appropriées. Un design rationnel des sites de stockage exige une bonne compréhension des phénomènes thermo-hydro-mécaniques interagissant au niveau de la barrière ouvragée et de la roche hôte proche. Pour y parvenir une formulation multiphysique, permettant de réaliser des analyses couplées THM et capable de reproduire les phénomènes observés, est décrite. La formulation est appliquée à la simulation de deux tests à échelle réelle : un essai dit « mine-by-test » concernant l'excavation d'un puits dans une roche argileuse et un test de chauffage à haute température dans une roche fracturée.