We are pleased to announce the release of iCP 1.6!

The new version of iCP is compatible with the newest versions of Comsol (5.4 & 5.5) and inherits their new features and capabilities:

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In this version, the performance is improved and several bug fixes are implemented.

The new features in iCP 1.6 include:

- Gas phase composition, volume, pressure and temperature can now be coupled between Comsol and PhreeqC.
- Kinetically controlled mineral dissolution and precipitation rates can be parametrized with physical variables calculated within Comsol.
- The initialization of iCP simulations and restart from checkpoints has been improved in terms of computational performance.

You can download iCP 1.6 and request an iCP license (if you don’t have one) filling in the registration form. 
More information about the release and installation instructions can be found in the User’s Guide. If you have 
any questions or comments, our team will be happy to answer them in the iCP forum.

We hope you will enjoy the new iCP interface in your reactive transport simulations! 

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We are pleased to announce the release of iCP 1.6!

iCP 1.6 Release

Coinciding with the release of iCP version 1.6, Amphos 21 is organizing an online iCP Training course on 10-12th November 2020.

This three-day course will cover the following topics:

* **1st day (10/11/2020):**

    * iCP overview and installation
    *  Introduction to Reactive Transport Modelling
    * Introduction to Comsol, focus on flow and solute transport in porous media
    * Hands-on iCP example: Cation exchange, part I

* **2nd day (11/11/2020):**

    * Introduction to PhreeqC
    * Hands-on iCP example: Cation exchange, part II
    * Hands-on iCP example: Calcite dissolution

* **3rd day (12/11/2020):**

    * Advanced hands-on iCP example
    * Advanced topics of iCP and on-going developments

The course will be held by expert lecturers in the use of Comsol, PhreeqC and iCP and with vast experience in the application of reactive transport in geosciences:

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<p>Jorge Molinero is the Scientific and Technical Director of Amphos 21. He received his PhD in Civil Engineering (University of A Coruña, Spain), and has 20 years of experience working with reactive transport simulations. Before joining AMPHOS 21 he was Assistant and Associate Professor at the Universities of A Coruña, Santiago de Compostela and UPC-Barcelona Tech.
</p>
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<p>
Elena Abarca is Group Manager in hydrogeology and reactive transport modelling at Amphos 21. She holds a PhD in Hydrogeology by the UPC – Barcelona Tech. Her work focusses in numerical modelling of groundwater flow and transport of (conservative and reactive) contaminants in porous media. Before joining Amphos 21, she was a Post-Doctoral Research Associate at the Auburn University (US) and the Massachusetts Institute of Technology (US).
</p>
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Andrés Idiart is a Civil Engineer with a PhD in Solid Mechanics and works as a Group Manager in engineering materials at Amphos 21. Andrés fields of expertise include geomechanics and the coupling between multiphysics and geochemistry.
</p>
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Emilie Coene is a consultant and iCP developer at Amphos 21 with a Chemical Engineering degree and a Master in Modelling for Science and Engineering. She is an expert in numerical model development and application. As a consultant at Amphos 21, she has been involved in several projects related with nuclear waste management, oil & gas and mining that involved reactive transport and multiphase-flow models.
</p>
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Marcelo Laviña is a consultant of the Modelling Solutions team at Amphos 21 Barcelona since 2016. He develops geomechanical and reactive transport models, specialising in the coupling of hydro-chemo-mechanical (HCM) processes in porous media. Marcelo obtained his Civil Engineering degree and his Master of Science degree from the Technical University of Madrid (UPM). During his last year at UPM, he was granted by the Hydraulics Department of the Civil Engineering School at UPM to perform research related with the modelling of hydro-geomechanical processes in fractured media
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<p>
Diego Sampietro is a consultant in the Modelling Solutions team at Amphos 21 since 2014. He is a Geologist with a postgraduate course in Hydrogeology and a master’s degree in mathematical modelling. Currently, he is doing a PhD thesis about reactive transport modelling in fractured systems. His main field of expertise includes the modelling of hydro-chemical processes in porous and fractured media. He is an advanced user of several modelling softwares such as Comsol Multiphysics or iCP.
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Ed González joined COMSOL Sweden in 2009 as a product manager, where he specializes in nonlinear materials modeling and porous media technology. He received his PhD in physics from LMU Munich.
</p>
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The cost of the course is 1,200 € and covers the lectures, lecture material, one permanent R&D license per participant and a 2h support session. The support session is personalized for each participant and can be used to work on a model of interest the first 15 days after the course.

Course registration is open until the 31st of October 2020. If you have any questions or doubts, please contact image@image-modelling.net. 

Course registration (Available until the 31st of October 2020) 

We look forward to seeing you in November!

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Coinciding with the release of iCP version 1.6, Amphos 21 is organizing an online iCP Training course on 10-12th November 2020.

iCP Training Course, 10-12th November 2020

The Challenge
===========

Physical transport in a heterogeneous porous media and non-uniform distributions of chemical and biological species in the natural subsurface environment exert scaling behavior of reactive transport processes. In most cases the fully characterization of the system is impossible because of the inherent random distribution of the material properties. This has led to the development of reactive transport models across a wide range of spatial scales. Continuum scale models (e.g. Darcy equation for flow) and spatial averaging, smooth out any heterogeneity of a scale comparable or smaller than the representative elementary volume (grid-spacing). The advances in both computational power and the development of new numerical algorithms, have made possible pore-scale calculations including advection and diffusion of reactant in a solid matrix with a complex topology. Pore-scale models are capable of simulating complex interplay and non-linear coupling between surface reactions, flow and diffusive transport as well as ability to solve for the distribution of reactant inside pores. One of such numerical paradigm is the lattice Boltzmann method (LBM) that was developed as an extension to cellular automata models for fluid flows [1,2,3].

Lattice Boltzmann Method
===================
The LBM approaches mass and momentum conservation equations from a kinetic theory standpoint, where the macroscopic variables of interest, the local density (or pressure with an equation of state) and momentum of the fluid are retrieved from the statistical moments of particle distribution functions that follow the evolution of a discrete set of Boltzmann kinetic equations (<b>Figure 1</b>).

<figure className="image">
  <StrapiImage className="mx-auto"  src="/uploads/Lattice_Boltzmann_Phreeqc_1_6e78b3f9e4.png" alt=""/>
  <figcaption><b>Figure 1</b>. Lattice topologies and lattice velocity indexing for the D2Q9 (a) and D2Q5 (b). (c) Schematic illustration of the bounce-back boundary condition at fluid–solid interfaces. The real and effective (numerical) boundaries are shifted by half a node for a straight interface (1st order accuracy) lattices. (d) Phase-field approach to surface reactions. Interface fluid nodes are considered for precipitation and interface solid nodes for dissolution. We use two flag variables, the first one is which corresponds to the type of nodes (solid or fluid dominated) and the second ζ which is null for all site but interface nodes where they can be   -1 depending on there location with respect to the fluid–solid interface [2].</figcaption>
</figure>

A pore-scale reactive transport model based on LBM has been previously developed to study heterogeneous dissolution-precipitation and sorption reactions in a complex porous media [1,2] (<b>Figure 2</b>). The model was successfully validated with analytical solutions of various 1D and 2D reactive transport problems. It uses recent advances in the development of optimal advection-diffusion solvers within the lattice Boltzmann method framework. Another novelty of the model is that the treatment of surface reaction is independent of the fluid-rock interface topology and orientation.

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<iframe width="560" height="315" src="https://www.youtube.com/embed/aDrscAjmYO8" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
  <figcaption><b>Figure 2</b>. Simulating arsenic sorption on various iron minerals (i.e. ferrihydrite, goethite and magnetite). Panel (a) depicts 2D distribution of disolved arsenic in the pore space while panels (b), (c) and (d) illustrates adsorbed arsenic concentrations on ferrihydrite, goethite and magnetite, respectively. Concentrations have been normalized with respect to their inital values.</figcaption>
</figure>

The new coupled LBM-PhreeqcRM model (LAMP) uses flow and transport solver based on the Lattice Boltzmann method with the chemistry solver PhreeqcRM in the pore-scale system. PhreeqcRM is a newly-developed geochemical reaction module designed specifically to perform equilibrium and kinetic reaction calculations for reactive transport simulators that use an operator-splitting approach [4]. It comprises methods to transfer concentrations and other model properties, and retrieve selected outputs. Coupling with PhreeqcRM enables the existing multicomponent pore-scale transport model to be extended to simulate wide range of geochemical reactions.

The coupling procedure includes: initialization of the domain for initial and boundary conditions with PHREEQC; transferring the data to the LBM-based flow and transport solver; performing transport step; transferring the data to PHREEQC and performing the reactions; and update porous media (if dissolution-precipitations occurs) and sending back to transport model until the final convergence and time step is reached.

Results and Discussion
==================
To test the accuracy of the coupling procedure, two verification problems were solved using LAMP: 1) chloride tracer test and 2) ion-exchange. Both scenarios were run in a 2D micro channel and results were compared with the ones obtained from a 1D Darcy-scale PHREEQC model. In the first example a boundary water with a chloride concentration of 0.001 mol/kgw is injected at the inlet of the domain, progressively displacing the initial water with zero concentration of chloride (<b>Figure 3</b>). The cross-section chloride concentration profile resembles the classis parabolic velocity profile in a 2D channel i.e. higher Cl concentration along the centerline of the channel while decreasing as it approaches to the walls. As water continues infiltrating from the inlet, peak of the profile approaches to Cl concentration of 0.001 mol/kgw and once it reaches to the maximum value, the sharp parabolic front flattens as Cl concentrations gradually increase towards the vicinity of the walls.

In the second example, similar physical setup is used while it is assumed that ion-exchange reactions take place along the walls of the channel (<b>Figure 3a</b>). Initially the medium contains an equilibrated potassium-sodium-nitrate solution with cation exchanger. The initial water, then is flushed with boundary water composed of calcium-chloride solution. In order to assess the effect of cation exchanger on the composition of the effluent, two points along the cross section of the channel is chosen: one in the middle of the cross section of the channel and the other in the vicinity of boundary wall. Close to the longitudinal boundary, results show that sodium initially present in the column exchanges with the incoming calcium and its concentration reaches to a fixed value as long as the exchanger contains sodium. In the centerline point, however, sodium is flushed out of the system as cation exchange reaction doesn’t take place. Potassium, close to the wall, is released after sodium because of larger K value in the exchange reaction and reaches a constant concentration after an initial increase. Similar to sodium, potassium is completely displaced by the boundary water along the centerline.

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  <StrapiImage className="mx-auto"  src="/uploads/Lattice_Boltzmann_Phreeqc_3_2db7e086d6.png" alt=""/>
  <figcaption><b>Figure 3</b>.  (a) Micro-channel geometry used for chloride transport and cation-exchange scenarios. In the cation-exchange problem it was assumed that exchanger exists along the longitudinal boundary walls. (b) Chloride front at the cross section of the channel (shown with the red line).</figcaption>
</figure>

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  <figcaption><b>Figure 4</b>. Temporal evolution of the aqueous species concentrations at points close to the boundary walls (where cation exchangers exist) and at the centerline.</figcaption>
</figure>

Acknowledgments
==================
The LBM transport solver was developed at Georgia Institute of Technology in collaboration with Dr. Christian Huber, and Dr. Andrea Parmigiani. Their contributions are gratefully acknowledged.

References:
==================
[1] Shafei, B., Huber, C., Parmigiani, A., 2013. Pore-scale simulation of calcite dissolution and precipitation using lattice Boltzmann method. Mineralogical Magezine 77 (5).

 [2] Huber, C., Shafei, B., Parmigiani, A., 2014. A new pore-scale model for linear and non-linear heterogeneous dissolution and precipitation. Geochimica et Cosmochimica Acta 124, 109-130.

[3] Kang, Q.J., Chen, L., Valocchi, A.J., Viswanathan, H.S., 2014. Pore-scale study of dissolution-induced changes in permeability and porosity of porous media. Journal of Hydrology 517, 1049-1055.

 [4] Parkhurst, D., Wissmeier, L., 2015. PhreeqcRM: A reaction module for transport simulators based on the geochemical model PHREEQC. Advances in Water Resources 83, 176-189.

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In this post, Reza Gooya (University of Copenhagen), Babak Shafei and Fidel Grandia, blog about a recently-developed coupled pore-scale lattice Boltzmann method with PhreeqcRM (LAMP).

A new coupled pore-scale LAttice Boltzmann Method with PhreeqcRM (LAMP)

Background
==============

An interface coupling two standalone codes, the geochemical calculator PHREEQC (Parkhurst and Appelo, 2013) and the multiphysics software COMSOL (COMSOL, 2013), has been developed recently by Amphos 21. The interface, called iCP (Nardi et al., 2013), is able to simulate complex thermo-hydro-mechanical-chemical (THMC) models.

The reactive transport process is solved using the operator-splitting (OS) technique (Strang, 1968) with a sequential non-iterative approach (SNIA). In this method the conservative solute transport is computed in a first step with COMSOL (coupled with other physical processes if desired) while the geochemistry is solved in a second step with PHREEQC.


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  <figcaption>Figure 1. Sequential non-iterative approach scheme of iCP, with the Molal solute transport interface highlighted.</figcaption>
</figure>

Despite COMSOL offers its own conservative solute transport interface, a new interface, “Molal solute transport”, have been developed for the specific needs of iCP. The interface is consistent with the units and the reactive transport formulation used in iCP. 

 Customizing COMSOL
==================
The interface was implemented using the Physic Builder toolkit of COMSOL. Within the Physic Builder environment, users can design customized interfaces through an interactive desktop and without the need of coding. The tailored interfaces can be exported as a plugin that can be added into the plugins folder of COMSOL and loaded every time the program starts. The interface will be, then, available as any other COMSOL module.

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  <figcaption>Figure 2. The Molal solute transport interface development in the Physics Builder environment.</figcaption>
</figure>

In the finite element method the governing equations have to be defined in weak form. Three different ways are available to introduce the weak form in COMSOL. In this case the weak formulation was implemented to allow a variable number of unknowns.

The Molal solute transport interface is able to model transport by advection and diffusion-dispersion. The interface can be used for steady-state and time-dependent analysis and in all kind of geometries supported by COMSOL.

The interface
=============
All features in the interface were tailored to meet the requirements of iCP. For instance, the term “Molal” comes from molality (mol/kg water), the default concentration units in PHREEQC; and the diffusion coefficient is constant for all the dependent variables, because in iCP formulation the transported elements are components and not “real” chemical species. 

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  <figcaption>Figure 3. Example of a model implementation with the Molal solute transport. </figcaption>
</figure>


Three default nodes are added to the Model Builder when using the interface: Conservative Transport (the governing equation), No Flow (the default boundary condition), and Initial Values. Many other boundary conditions can be added: Fixed Concentration, Outflow, Open Boundary and Mass rate.

 The interface has been tested in various models, both reactive and conservative transport, performing similarly to other solute transport codes.

Acknowledgements
================

This work was made possible by the funding from the European Union's through the CO2-ReactMarie Curie Initial Training Program and has been conducted at Amphos 21 in close collaboration with Albert Nardi

References:
================
 

[1] *Parkhurst, D.L. & Appelo, C.A.J.,* 2013.  **Description of input and examples for PHREEQC version 3—A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations. ** U.S. Geological Survey Techniques and Methods, book 6, chap. A43, p.497 p. Available at: http://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/

 

[2] *COMSOL, 2013*. Comsol Multiphysics. Version 4.3a, Available at: www.comsol.com.

 

[3] *Nardi, A., Idiart, A., Trinchero, P., de Vries, L. M. and Molinero, J.* (2013). ** ‘Interface Comsol-PHREEQC (iCP), an efficient numerical framework for the solution of coupled multiphysics and geochemistry’,  **Computers & Geosciences, submitted. Available at: http://image-modelling.net/icp.

 

[4] *Strang, G., *1968. **On the construction and comparison of difference schemes. ** SIAM J Numer Anal, 5, pp.506-17.

 



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In this post, Álvaro Sáinz, Marie Curie PhD student at Amphos 21, blogs about a COMSOL interface he has built to simulate conservative transport in porous media.

Molal solute transport: customized physics interface for iCP

The problem
================
Disposal in a deep underground repository is currently considered by several countries as the preferred option for long-term management of spent nuclear fuel. For regulatory reasons the safety of such a disposal facility must be demonstrated quantitatively through Performance Assessment calculations. One of the factors that have the potential to significantly influence the results of Performance Assessment is the radionuclide release rate from the waste immediately upon contact with groundwater (the so called **Instant Release Fraction**). Performance Assessment calculations indicate that instant release is important for the overall safety assessment of the facility, but there are significant uncertainties about the nature of this phenomenon and how it should be represented in Performance Assessment.

 With the above in mind, the **FIRST-Nuclides** Collaborative Project was funded by the European Commission under the 7th Framework Programme of the European Atomic Energy Community (EURATOM). The project has been initiated to provide better (conceptual and quantitative) understanding of the processes involved in instant release of radionuclides from spent nuclear fuel.

In the context of instant release, the knowledge of the rate of spent fuel saturation with water is key as the release of some radionuclides is contingent upon wetting of the fuel surfaces by water. Therefore, the instant release rate of these radionuclides depends on the rate of spent fuel saturation. An improved understanding of the rate of spent fuel saturation with water will help elucidate radionuclide instant release both under repository conditions and with regard to laboratory experiments conducted under near-room conditions.

Approach
=======

Under repository conditions the exposure of spent fuel to groundwater would be conditional upon the failure of multiple interconnected engineered barriers. The processes involved in such a phenomenon are multiple and coupled, making the system highly complex.

As a point of departure therefore, the saturation of a single idealised spent fuel pellet was considered (henceforth referred to as the *Reference Pellet*). This situation can be thought of as representative of batch laboratory leaching experiments performed on complete or fragmented fuel pellets, which are performed in order to measure radionuclide release rates from spent fuel upon contact with water. The results of modelling of saturation with water of a single spent fuel pellet are directly applicable to the interpretation of laboratory leaching results, but are also the necessary first step towards more complex multiphysics models capable of representing the fate of spent fuel upon wetting under repository conditions.


The conceptual model assumed that the pellet was composed of an impervious to water UO2 matrix and a network of (thermal) cracks, which can be filled with water (Figure 1). By saturation with water of the pellet is therefore understood the process of filling up of these cracks with water.

 

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  <figcaption>Figure 1: The conceptualised Reference Pellet (left – lines indicate intersection of cracks with the pellet’s surface) and the finite element mesh (right) of the idealised crack system. Note that water flow is considered to occur through the cracks only (the fuel matrix is impervious to water). Dimensions shown are in metres.</figcaption>
</figure>

Implementation in Comsol
======================
Water penetration into the interconnected system of cracks was simulated by solving the Richard’s equation (in the pressure-based form). This was implemented in Comsol utilising the Fracture Flow interface (calculation of flow in discrete fractures), which was modified by manually implementing a storage-retention term and a set of constitutive equations (the water retention model) so as to account for variably-saturated flow within the cracks. More details on the conceptual and numerical details of the model can be found in [1].

The primary variable solved for is water pressure, which, through the water retention model, links directly with water saturation. In order to represent the physics of water penetration a negative water pressure (positive capillary suction pressure) was prescribed homogenously within the cracks, while a positive pressure (here corresponding to 5 cm of water column) was applied to all external crack edges. The driving force for water penetration into the cracks is water pressure (capillary suction) gradients (Figure 2), which disappear after the saturation process is complete.

<figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/modelling_saturation_figure_2_070a9e6cf2.png" alt=""/>
  <figcaption>Figure 2: Successive stages of saturation with water (from left to right) of an interconnected system of cracks in a single spent fuel pellet. The colour scale represents effective saturation (-), which varies from the initial value of 0.1 ‰ (deep blue) to unity (red) at full saturation.</figcaption>
</figure>


Insights Gained
=============
The model enables quantification of the time needed to completely saturate a given system of cracks, which may vary depending on the statistical properties of the cracks (e.g. their number, geometry, interconnectivity and aperture), and depending on the initial and boundary conditions used (e.g. representing the presence of partial cladding or depth at which water penetration occurs). This is useful information as it makes it possible to compare the crack system surface wetting rate with the rate of radionuclide release observed in laboratory leaching experiments. Preliminary results of this on-going work indicate that, indeed, the time scales for cracks saturation with water are comparable with those operationally defined for instant/fast release of some radionuclides (hours to weeks).

We are currently working on an implementation of tracer release from the crack surface and transport by diffusion through the crack system towards an external reservoir (experimental batch solution or rock formation water in case of repository conditions). Also, the saturation model is being extended to include two distinct, but interconnected, populations of cracks (of different mean apertures). Ultimately, we intend to include relevant chemical reactions (e.g. dissolution of the fuel matrix at later stages) and upscale the model to the rod assembly scale. Work progress and results obtained in this work will continue to be presented and discussed at this blog.

Acknowledgements
================
The research leading to these results has received funding from the European Union's European Atomic Energy Community's (Euratom) Seventh Framework Programme FP7/2007-2011 under grant agreement n° 295722 (FIRST-Nuclides project). 

This work was carried out with important contributions from Amphos 21 colleagues: Andrés Idiart, Lara Duro and Olga Riba.

References
================
[1] *Pękala et al.* 2012. **Modelling of spent fuel saturation with water – approach, preliminajry results and potential implications. **In: KIT Scientific Reports 7639, 1st Annual Workshop Proceedings of the Collaborative Project “Fast/Instant Release of Safety Relevant Radionuclides from Spent Nuclear Fuel (7th EC FP CP FIRST-Nuclides).

 



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In this post, Marek Pękala describes a recent application of Comsol at Amphos 21 to study the saturation with water of spent nuclear fuel.

Modelling saturation with water of spent nuclear fuel in the context of its geological disposal

Scope and objectives
==================
In the framework of safety assessment studies for depth geological disposal of nuclear waste, important scientific efforts are needed in order to understand the feasibility of the planned repositories. This is precisely the case of Olkiluoto in Finland, where the land uplift, related to the withdrawal of ice from the last glacial Age, plays a pivotal role in the hydrogeological patterns of the site. It is thus very important to improve the knowledge about the past evolution of the hydrogeological and geochemical conditions. In fact, as a result of land uplift, the infiltration of meteoric water could have triggered weathering processes, which, in turn, have impact on key parameters controlling the long-term stability of the planned repository (pH and redox conditions, availability of mineral buffers, etc). Furthermore, the presence of sulphate-rich waters along with bacterial communities and substrate might activate microbial mediated sulphate reduction processes with the related generation of, which is a detrimental agent for the copper canisters where the waste is placed.

<figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/coupled_palaehydrogeological_microbial_figure_1_4d26cbef8c.png" alt=""/>
  <figcaption>Geographical location of Olkiluoto Island and related fractured system object of simulations. It is shown the initial density field in depth.</figcaption>
</figure>

Numerical model
==============
In order to improve the understanding of the effect of the aforementioned events on the current hydrochemical conditions, we have developed a complex three-dimensional palaehydrogeological reactive transport model of the Olkiluoto site. The model consist of four hydrogeological zones of the Well Characterized Area (WCA), namely BFZ100, HZ19A, HZ19B and HZ19C. The Palaeohydrogelogical Reactive Transport (PRT) simulations, which spans 2000 years (from 0AD to present), aim at capturing the mutual interplay of different processes (i.e. land uplift, intrusion of meteoric water, weathering, mixing of waters etc.). The hydrogeological zones are simulated as two-dimensional planes within a three-dimensional domain. 

 <figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/coupled_palaehydrogeological_microbial_figure_2_d60154d447.png" alt=""/>
  <figcaption>Detail of the hydrogeological zones and FE grid</figcaption>
</figure>

The numerical model has been implemented using the Interface COMSOL-PHREEQC (iCP), which has been developed and validated by Amphos 21. To increase the reliability of the PRT simulations, groundwater flow parameters (i.e. residual pressures and density fields) are taken from an existing  palaeohydrogeological flow model (Löfman and Karvonen, 2012)

Some Results
===========
After some preliminary runs, different sets of three-dimensional PRT simulations have been carried out. In each of these simulations the geochemical complexity of the system has been progressively increased by including new processes (e.g. mineral equilibrium → mineral equilibrium and kinetics → mineral equilibrium, mineral kinetics and cation exchange). 

 
 <figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/coupled_palaehydrogeological_microbial_figure_3_0ff817dfc0.png" alt=""/>
  <figcaption>Detail of sulphide distribution in mol/L (x10-5) for 2000 AD</figcaption>
</figure>


 <figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/coupled_palaehydrogeological_microbial_figure_4_ba61628795.png" alt=""/>
  <figcaption>Detail of calcite distribution in mol/Kg for 2000 AD</figcaption>
</figure>

The results of the PRT simulations have been compared with the available field data and the general good agreement of the results has highlighted both the reliability of the model and its potential for the prediction of the  future evolution of the geochemical conditions at Olkiluoto.

 <figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/coupled_palaehydrogeological_microbial_figure_5_b154cae116.png" alt=""/>
  <figcaption>Sulphate distribution in depth for 2000 AD</figcaption>
</figure>

Acknowledgements
=================
This work has been funded by POSIVA. Amphos 21 wants to thank Petteri Pitkänen and Lasse Koskinen for their support and very helpful comments. Miguel Luna also wants to thank the coauthors of this work: Paolo Trinchero and Jorge Molinero.

medium_coupled_palaehydrogeological_microbial_figure_2.png

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A large-scale, long-term simulation of the hydrogeochemical behaviour of fractured rocks is shown in this post. 

Coupled Palaehydrogeological Microbial and Geochemical Reactive Transport Model of the Olkiluoto Site (Finland)

Background
============
Several coupled Hydro-Mechanical-Chemical (HMC) processes are involved during the construction and operation of a heap leach pad. Due to the complexity of the problem, common existing heap leaching models solve the different phenomena in an uncoupled or partially coupled way. Also, often modeling of leaching of copper oxide ores assumes that mineral dissolution/precipitation is described by the diffusion-controlled shrinking core model and the system is composed by a single copper-containing mineral and a single mineral representing the gangue. Although these simplifications help to solve the problem, they could result in poor predictions of the composition of the pregnant solution (PLS) and consequently, an over- or under- estimation of the copper recovery and acid consumption. Further, improving the design of heap leach pads requires performing an integrated analysis of the HMC phenomena. Mechanics stability and mineral recovery efficiency cannot be estimated accurately without considering multiple coupling of the complex chemistry, soil mechanics and hydrodynamics. Here we present a coupled HMC model that accounts for the kinetics of several mineral species and the evolution of a muti-lift heap. Numerical simulations were performed with Comsol-PhreeqC (iCP), an interface that allows solving coupled unsaturated flow, soil mechanics and reactive transport using the Sequential Non Iterative Approach (SNIA).

 

Numerical implementation in iCP
==========================
The HMC governing equations are solved with the numerical interface Comsol-PhreeqC (iCP) (Nardi et al., 2013). iCP is a Java interface that couples the general purpose finite element framework Comsol Multiphysics (www.comsol.com) and the geochemical simulator PHREEQC (Parkhurst and Appelo, 1999; http://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/). In brief, the tool is based on implementing an operator splitting technique for solving the hydro-mechanical problem (a coupled or uncoupled system of partial/ordinary equations and algebraic differential equations) on Comsol and the chemical system of algebraic and differential equations on PHREEQC.

Simulation of a multi-lift heap leach pad
====================================
The present HMC model was applied to simulate the construction and operation of a synthetic copper heap leach pad consisting of five ore layers settled on a terrain with a slope of 2%. Each layer is simulated sequentially, mimicking the sequence of construction and operation of a real heap leach pad. We assumed that the construction of each layer is performed during 10 d, followed by an irrigation period of 90 d at a constant irrigation rate of 7.5 l/h-m2. The stacked ore consists of an artificial mineral mixture made from Chrysocolla (20% w/w), Chalcopyrite (10% w/w), Pyrite (8% w/w), Albite (30% w/w) and K-Feldspar (32% w/w), whose chemical evolution is assumed to be governed by kinetics reactions. Equilibrium precipitation-dissolution reactions of Jarosite-K, Jurbanite, Basaluminite, FeOH3(a) and Schwertmannite were also taken into account.

The figure below shows the evolution of concentrations of selected dissolved species at the output of the drainage system. The evolution of pH shows the arrival of the acidic solution to the liner system in a time of around 60 d (top left). Kinetic dissolution of Chrysocolla and Chalcopyrite are triggered by the infiltration of the acidic solution and, as a result, an increase of Cu concentrations is observed in the outlet flow (top right). The chemical evolution of impurities like Si and Al (bottom) clearly shows that under this low pH conditions kinetic dissolution of alumina-silicates is also favoured. This process is highly dependent on the pH and, over a long period of time, porosity can be significantly modified. As expected, the composition of the PLS responds to the irrigation and drainage rates of the system (shown in grey colour).



<figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/copper_heap_leaching_figure_1_024bc9026d.png" alt=""/>
  <figcaption>Evolution of pH (a) and concentrations of Cu (b), Si (c) and Al (d) in the pregnant leach solution.</figcaption>
</figure>


 

Chrysocolla and oxide minerals leach rapidly under heap leach conditions. Chalcopyrite hardly reacts at all in heap leaching. The video below shows that the Chalcopyrite concentration (middle) practically does not change, while the Chrysocolla (top) is almost completely dissolved at the end of the leaching of each layer. The latter has a major impact on the porosity of the ore bed (bottom).

 
<figure className="image">
<iframe width="560" height="315" src="https://www.youtube.com/embed/vYcgOlo9O_o" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
  <figcaption>Evolution of Chrysocolla (top) and Chalcopyrite (mid) concentrations and porosity due to chemical reactions (bottom).</figcaption>
</figure>
 

The copper recovery and acid consumption curves (see the figure below) directly reflect the different dissolution rates of the mineral species considered in the model, specially the Chrysocolla (fast dissolution rate) and the Chalcopyrite (slow dissolution rate). The first layer provides a copper recovery of about 30%, while the copper recovered from the leaching of subsequent layers is about 8%. At the end of the operation (500 d), approximately the 60% of the copper has been recovered. The copper recovering increases due to the leaching of residual mineral from previous layers, depending on the thickness of the loaded layers and the irrigation times. The competition between Chrysocolla and Chalcopyrite is also evidenced by the acid sulphuric consumption. The acid consumption during the leaching of a new layer is progressively lower than the acid consumption of previous leaching stages. This is because the mass of mineral of the new layer is lower and the impact of acid consumption from previous leached layers is minor.

 
<figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/copper_heap_leaching_figure_3_20d4aa9811.png" alt=""/>
  <figcaption>Predicted copper recovery (top) and acid consumption (bottom).</figcaption>
</figure>

Changes in porosity and permeability due to mineral dissolution/precipitation and irrigation time can affect significantly the hydromechanical behavior of the heap leach pad. First, the hydrodynamics behavior of the system is conditioned by the time that takes the irrigation solution to saturate the heap as it flows to the drainage system. After a short period of time, a quasi-steady state is achieved for every layer. Secondly, the mechanical effects are traduced in an increase in the vertical stress developed mainly on the rock foundation as the layers are progressively loaded. This vertical stress increase also reaches the top of the third layer, where the vertical displacement reaches a maximum. The evolution of liquid saturation, Darcy velocity field and vertical stress is shown in the next video.

<figure className="image">
<iframe width="560" height="315" src="https://www.youtube.com/embed/iM1oiOpNlOI" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
  <figcaption>Evolution of liquid saturation and Darcy velocity field (top) and vertical stress (bottom) in the leach pad.</figcaption>
</figure>
 

There are zones of the ore where the porosity increases due to the mineral dissolution and other zones where the consolidation of the layers leads to a porosity decrease. In the present application case, chemical predominates over hydromechanical effects. The figure below (top) shows the combined hydromechanical and chemical effects on the global porosity at an observation point (white dot in the previous video). The consolidation of the lifts related to the porosity decrease is illustrated in the figure below (bottom) in terms of the vertical displacement at the cross section A-A´ shown in the previous video. The maximum vertical displacement is obtained at mid height, which seems to be in agreement with field observations.

 
<figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/copper_heap_leaching_figure_5_1b37d3a52f.png" alt=""/>
  <figcaption>Evolution of porosity at the centre of the first lift (top) and vertical displacement (bottom) at the cross section A-A’.</figcaption>
</figure>


Conclusions
============
The results show that changes in porosity and permeability due to mineral dissolution/precipitation and irrigation time affect significantly the hydromechanical behavior of a heap leach pad, and vice versa. A strong advantage of the present model is that it can treat multiple chemical species simultaneously, providing solutions that are best for interpreting all the chemical interactions within a leaching system. The stability of the pad and the ore recovery efficiency can be predicted with more accuracy because the model considers the interaction between variable saturated flow, mechanical deformation and chemical reactions during the construction and operation of the heap.

Acknowledgements
============
I would like to express my gratitude and appreciation to Albert Nardi and Mayu Tincopa who laid the foundations for this research. I also want to acknowledge the partners of the iMaGe consortium (www.image-modelling.net) for supporting the iCP development.

References
============
*Nardi, A., Idiart, A., Trinchero, P., de Vries, L. M. and Molinero, J. *(2013). **‘Interface Comsol-PHREEQC (iCP), an efficient numerical framework for the solution of coupled multiphysics and geochemistry’, **Computers & Geosciences, submitted.

*Parkhurst, D. L. and Appelo, C. A. J. *(1999).** ‘User's guide to PHREEQC (version 2)-A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations’, **U.S. Geological Survey Water-Resources Investigations, vol Report 99–4259, 312 p.

thumbnail_copper-heap-leaching_overview.png

copper-heap-leaching_overview.png

Heap leach pads constitute a common practice in the mining industry.

Hydro-mechanical-chemical coupled modeling of copper heap leaching with iCP

The challenge
=============

The Swedish Organization for Radioactive Waste Management, SKB, plans the disposal of spent nuclear fuel in a deep geological repository. Bentonite clay is planned to be used around the cylindrical waste packages as buffer material due to its low permeability and high swelling properties. To assess alternative clay materials, SKB started a field experiment in 2006 [1] where packages of different types of compacted bentonite hollow cylinders were placed and heated (> 100 ºC) from the inside to target values during ~2.5yr (Figure 1). Post-mortem analysis indicated that initially contrasting cation-exchanger compositions between different bentonite blocks significantly homogenized already after 880 days (Figure 2). The question arose of whether these observations can be reasonably well described by our conventional tools and understanding of the underlying processes. 




<figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/modeling_bentonite_figure_01_902f919667.jpg" alt=""/>
  <figcaption>Installation of the package and conceptualization in Comsol model.  </figcaption>
</figure>

 

<figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/modeling_bentonite_figure_02_12c1723b4f.png" alt=""/>
  <figcaption>Initial (before) and final (after the experiment) exchanger composition in terms of unit fraction Na, Ca, Mg and K occupancy (empty: no data available).  </figcaption>
</figure>



 
Comsol: an ideal platform for simple tailored models
=======================================
 

To verify whether a simple reactive transport model coupling diffusion, cation-exchange and temperature evolution can explain the observed homogenisation of cation-exchanger composition, a simplistic geochemical model was implemented in Comsol and coupled to physical processes. The model considers different porewater compositions for each clay material assuming chemical equilibrium and only 5 ionic species: Na+, Ca2+, Mg2+, K+ and Cl-. Fickian diffusion (coupled to temperature evolution based on experimental data) is the only transport process while cation-exchange is the only type of chemical reactions implemented. The implementation of diffusion uses the “Solute Transport” Interface, while cation-exchange is set through a system of coupled non-linear algebraic equations. Transport-Chemistry coupling uses the approach proposed in [2] and solved using Operator Splitting. More details can be found in [3].

 

Results: when modeling meets real experiments
=====================================

In conjunction with a composite boundary type (Figure 3) based on fracture logging measurements, the simple model is capable of reproducing the experimental data with reasonably good accuracy, especially for the dominant cations (Ca and Na). A relatively poorer fit for Mg is observed in the top (although still unclear, it could be due to additional chemical reactions or altered groundwater composition). Thus, we see how a very simple model (Figure 4) can be very useful to gain insight in the experiment evolution and serve as a basis for discussion between experimentalists. The model independently showed that part of the homogenization is most probably due to the higher water renewal in the fractured zone of the deposition hole.

 


<figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/modeling_bentonite_figure_03_d0d83660ea.png" alt=""/>
  <figcaption>Left – schematic representation of the model domain and its boundaries (blue: no-flux, red: constant concentration). Right – final experimental and simulated exchanger compositions (after 880 days) across the package.</figcaption>
</figure>

 

<figure className="image">
  <StrapiImage  className="mx-auto"  src="/uploads/modeling_bentonite_figure_04_9c89975751.png" alt=""/>
  <figcaption>Time evolution of Ca unit fraction on the cation exchanger. From initial 
</figcaption>
</figure>
 

Acknowledgments
==============
This work was made possible by the financial support from SKB and has been conducted at Amphos 21 by Marek Pekala, Andrés Idiart, Albert Nardi, and David Arcos. Their contributions are gratefully acknowledged.

References
=========
[1] *Svensson D. et al.,* 2011. Alternative Buffer Material – **Status of the ongoing laboratory investigation of reference materials and test package **1. SKB TR-11-06.

[2] *Saaltink M. et al., *1998.** A mathematical formulation for reactive transport that eliminates mineral concentrations. **Water Resources Research, 34, 1649-1656.

[3] *Idiart AE, Pękala M, Nardi A, Arcos D,* 2012. **Reactive transport processes in compacted bentonite. Application to a prototype experiment of underground repository for nuclear waste. **Int. Meeting Clays in Natural & Engineered Barriers for Radioactive Waste Confinement, Montpellier, France.



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modeling_bentonite_figure_04.png

This post is about a recent application case of Comsol in the field of thermo-hydro-geochemical behavior of clayey materials 

Modeling reactive transport processes of an in-situ test in compacted bentonite

The safety assessment of deep geological repositories (DGR) for used spent fuel (SF) requires a fundamental understanding of the processes controlling fuel alteration and the release of radionuclides into the geosphere.

The corrosion of the containers in which the spent fuel is stored will eventually lead to container failure and groundwater inflow. Water entering the failed container will be devoid of oxygen due to the corrosion of steels and cast iron, ensuring a low redox potential by the production of H2 and Fe(II). Subsequently, the oxygen depleted water will get in contact with the spent fuel experimenting radiolysis by the effect of alpha radiation (emitting gamma and beta fission products are expected to be decayed at repository times greater than 10.000 years, when failure of the container is expected). Water radiolysis generates both oxidizing and reducing species in solution: H<sup>+</sup>, OH<sup>-</sup>, O<sub>2</sub>, H<sub>2</sub>O<sub>2</sub>, H<sub>2</sub>, HO<sub>2</sub><sup>-</sup>, HO<sub>2</sub>·, O·, O<sup>-</sup>, O<sub>2</sub>-, H·, ·OH and e- [1]. Taking into account that the reducing effect of H<sub>2</sub> is inhibited by its slow kinetics, radiolysis could potentially lead to relatively fast oxidative dissolution despite the bulk reducing environment. However, some fission products contained in the irradiated fuel have shown to be able to activate H<sub>2</sub> through their catalytic effect. We refer to the epsilon particles (Rh, Pd, Ru), whose catalytic effect can result in low H<sub>2</sub> concentrations, suppressing the oxidation of UO<sub>2</sub> [2-4]. The high complexity of the described system is schematically represented in **Figure 1**. 

<figure className="image">
      <StrapiImage
        src="/uploads/euratom_safety_assessment_1_0931a293fb.png"  className="mx-auto" alt=""
      />
  <figcaption><b>Figure 1</b>. Interrelated processes involved in the spent fuel matrix alteration.</figcaption>
</figure>

In the framework of EURATOM Project “DisCo” (modern spent fuel Dissolution and chemistry in failed Container conditions), carried out within the Horizon2020 framework program, Amphos 21 has integrated the processes occurring at the spent fuel surface (see **Figure 1**) with a 1D reactive transport model. The model has been implemented in iCP [5], using the two-way coupling approach shown in **Figure 2**. 

<figure className="image">
      <StrapiImage
        src="/uploads/euratom_safety_assessment_2_0a79e24c73.png"  className="mx-auto" alt=""
      />
  <figcaption><b>Figure 2</b>. Integration in iCP of the different processes involved in the SF alteration.</figcaption>
</figure>

The complete water radiolysis scheme, integrating more than 35 kinetic reactions together with the yields of primary products [1, 6] (included in Appendix 1) has been implemented in COMSOL though a set of ordinary differential equations (ODE) and were coupled with the solute transport equation (Eq. 1) through a source term in Riba et al. (2020) [7].

$$
\phi\frac{\partial c_i}{\partial t}+\mathrm{\nabla}\left(-D_e\mathrm{\nabla}c_i\right)=S_i+\sum_{j} R_{ij} 							$$

The SF matrix has been modelled as amorphous UO2 with a homogeneous chemical composition and containing 1 atom % of Pd, as representative element of the epsilon particles. The kinetic reactions related to the alteration of SF and Fe(s) corrosion are implemented in PhreeqC (see **Figure 2**).

The interrelated processes described above have been implemented in a 1D model with the geometry presented in Figure 3 to simulate a DGR concept where the iron insert of the copper canister is at 10 mm from spent fuel rods [8]. A uniform alpha dose rate of 2.86·10<sup>-2</sup> Gy·s<sup>-1</sup>  affecting the first 13 &mu;m in water adjacent to the SF surface was assumed in the 1D simulation. This uniform alpha dose rate is equivalent to a non-uniform exponential distribution of dose rate affecting 35 μm in water adjacent to the SF surface, in the sense that both produce the same total dose rate [9].

<figure className="image">
      <StrapiImage
        src="/uploads/euratom_safety_assessment_3_5ca2e9d13f.png"  className="mx-auto" alt=""
      />
  <figcaption><b>Figure 3</b>. Geometry (not to scale) considered in the 1D models that consider a geometry comparable to that of the spent fuel in the DGR.</figcaption>
</figure>

**Figure 4** shows the temporal evolution of the total U, U(IV) and Fe<sup>2+</sup> concentration profiles.  The total U concentration is in accordance with the Eh in the different domains and at different simulation times. Notice the sharp increase of both [U] and Eh after 20 days of simulation time. 

<figure className="image">
      <StrapiImage
        src="/uploads/euratom_safety_assessment_4_affde9483b.gif"  className="mx-auto" alt=""
      />
  <figcaption><b>Figure 4</b>. Modelling results considering the geometry detailed in Figure 3 and porous matrix of SF of 4mm.</figcaption>
</figure>

This modelling approach has solved the challenge of coupling the complete water radiolysis system with chemical complexation reactions and dissolution/precipitation processes which occur at very different time scales, often with rates differing by more than 6 orders of magnitude.

The model not only integrates the radiolysis of water but also these two important systems: uranium (as the main element of the fuel) and the iron of the steel-container and metallic insert, having, both of them, a very complex chemistry. Also, it has the flexibility for future inclusions of other chemical processes to account for the complex system of SF, steel container and water chemistry. Therefore, it represents a step forward towards the development of the models needed to assess the performance and the safety of a DGR for spent nuclear fuel.

References
========
[1] *Kelm, M., Bohnert, E. *(2004) **A kinetic model for the radiolysis of chloride brine, its sensitivity against model parameters and a comparison with experiments**, Forschungszentreum Karlsruhe, FZKA 6977.

[2] *Carbol, P. Fors, T.Gouder, K. Spahiu *(2009). **Hydrogen suppresses UO2 corrosion**. Geochimica et Cosmochimica Acta 73 (2009) 4366–4375.

[3] *Trummer, T., M. Jonsson M, J.* (2010). **Resolving the H2 effect on radiation induced dissolution of UO2-based spent nuclear fuel **Nucl. Mater., 396, 163–169.

[4]* Ollila K* (2011). **Influence of Radiolysis on UO2 Fuel Matrix Dissolution Under Disposal Conditions - Literature Study**. Posiva Working Report 2011-27, 64 pp. Posiva Oy, Olkiluoto, Finland.

[5] *Nardi, A., Idiart, A., Trinchero, P., de Vries, L. M., and J. Molinero *(2014). **Interface COMSOL-PHREEQC (iCP), an efficient numerical framework for the solution of coupled multiphysics and geochemistry. **Computers & Geosciences 69: 10-21.

[6] *Eriksen, T. E., Jonsson, M., Merino, J.* (2008). Modelling of time resolved and long contact time dissolution studies of spent nuclear fuel in 10 mM carbonate solution–a comparison between two different models and experimental data. Journal of Nuclear Materials, 375(3), 331-339.

[7] *Riba, O., Coene, E., Silva, O., Duro, L.* (2020). **Spent fuel alteration model integrating processes of different time-scales.** MRS Advances, 5(3), 159-166.

[8] *Raiko *(2012). **Canister design 2012**. Posiva Report 2012-13.

[9] *Wu, L., Beauregard, Y., Qin, Z., Rohani, S., Shoesmith, D. W.* (2012). **A model for the influence of steel corrosion products on nuclear fuel corrosion under permanent disposal conditions**. Corrosion Science, 61, 83-91.

[10] *Christensen, H., Sunder, S., Shoesmith, D. W.* (1994).** Oxidation of nuclear fuel (UO2) by the products of water radiolysis: development of a kinetic model. Journal of alloys and compounds**, 213, 93-99.

[11] *Cera, E., Bruno, J., Duro, L., Eriksen, T. *(2006). **Experimental determination and chemical modelling of radiolytic processes at the spent fuel/wáter interface**. SKB TR 06-07, Svensk Kärnbränslehantering AB.

Appendix A
=========

Kinetic reaction scheme  for water radiolysis [1]

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      <StrapiImage
        src="/uploads/euratom_safety_assessment_appendix_1_8b4339d20d.png"  className="mx-auto" alt=""
      />
</figure>

Yields of primary products (mol·l<sup>-1</sup> x 10<sup>7</sup>) formed on radiolysis of water

<figure className="image">
      <StrapiImage
        src="/uploads/euratom_safety_assessment_appendix_2_875e8e8d0d.png"  className="mx-auto" alt=""
      />
</figure>

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The safety assessment of deep geological repositories (DGR) for used spent fuel (SF) requires a fundamental understanding of the processes controlling fuel alteration 

Spent fuel matrix alteration model under Deep Geological Repository conditions

We are pleased to announce the release of version 2.0 of iCP! iCP 2.0 includes new capabilities such as adding extra dimensions and chemo-mechanical couplings and has been updated for compatibility with the latest releases of Comsol and PhreeqC. 

You can download iCP 2.0 [here](/static/downloads/iCP-v2.0.zip) and you can request license by filling in the [license form](/form/icp-license-request/).

The following list outlines all the new capabilities/improvements added in iCP 2.0: 
- **Extra dimensions** can now be added to your reactive transport models. Extra dimensions extend a standard geometry with additional spatial dimensions and can be used to represent a rock matrix in a fracture-matrix system. The developments carried out in the iCP code allow to include chemical reactions in both domains, the extra dimension representing the matrix and the fracture. The main benefit of this methodology is the possibility to include matrix diffusion in discrete fracture networks (DFNs) of thousands of fractures with complex intersections, see for instance the animation below. It can be challenging or impossible to mesh the fractures and rock matrix with such a complex geometry. In this context, the extra dimensions of COMSOL can be very handy when the matrix has low permeability and transport is diffusion dominated. An example (Example 3) has been added to the examples library to demonstrate how to set up a model with extra dimensions. 

<figure className="image">
      <StrapiImage
        src="/uploads/extradim_dcd8cc3c5a.gif"  className="mx-auto" alt=""
      />
</figure>

- **Mechanical modelling** performed in Comsol can now be coupled with reactive transport with iCP.  These capabilities can be used to model the chemical degradation of concrete and its impact on mechanical properties (see animation below) or to predict the swelling potential of bentonite under different geochemical conditions. Chemo-mechanical coupling is demonstrated with Example 4 in the examples library. 

<figure className="image">
      <StrapiImage
        src="/uploads/mechanics_gif_9d4abcd0ff.gif"  className="mx-auto" alt=""
      />
</figure>

- The amount of exchanger and surface complexes specified in PhreeqC can now be updated from Comsol. This can be used to model variations in number of sites or cation exchange capacity due to mineral dissolution/precipitation. 

- iCP 2.0 is compatible with the latest releases of Comsol: versions 5.4, 5.5 and 5.6. iCP 2.0 by runs Comsol in Standalone mode (without Comsol server) by default, which improves computational performance and memory handling. Note that this option is not available with Comsol 5.5. 

- iCP 2.0 is compatible with Comsol physics that include internal DOFs. This means that physics can now be run with the Compute boundary fluxes option enabled.

- The IPhreeqC library has been updated to the latest version, 3.7.0.

- The default water content used by iCP (when it is not coupled) is now the value specified in the input PhreeqC files. Note that in previous versions this value was overwritten by default by 1 kg of water. 

- Error logging has been improved in iCP 2.0. When an error occurs in the chemical step, iCP now specifies the coordinates at which the error occurred. Also, when an error occurs in the transport step the full error message given by Comsol is displayed.


icp20.png

We are pleased to announce the release of version 2.0 of iCP! iCP 2.0 includes new capabilities such as adding extra dimensions and chemo-mechanical couplings.

iCP v2.0 release

On June 2021, the new version of <a href="/technology/interface-comsol-phreeqc/">iCP</a> (v 2.0) was released. One of the several improvements and capabilities included in this version is the possibility to add extra dimensions to your reactive transport models. Extra dimensions extend a standard geometry with additional spatial dimensions and they make it possible to solve PDEs in any number of independent variables, beyond 3D and time. For fracture-matrix systems, the extra dimension approach included in iCP allows to account for matrix diffusion mechanisms with their geochemical implications without having to represent the matrix explicitly in the finite element mesh. This approach simulates the movement of chemical species trough the fractures and diffusion through the matrix by representing the low permeable matrix as a set of individual 1D elements (lines) connected to the nodes of the fracture (**Figure 1**).

<figure className="image">
      <StrapiImage
        src="/uploads/icp_extradims_1_9155611965.png"  className="mx-auto" alt=""
      />
<figcaption><b>Figure 1</b>. Scheme showing the connectivity between the elements of the extra dimension (blue squares) and the discrete fracture (red).</figcaption>
</figure>

The developments carried out in the iCP code allow to include chemical reactions in both domains, the extra dimension representing the matrix and the fracture. The main benefit of this methodology is the possibility to include matrix diffusion in discrete fracture networks (DFNs) of thousands of fractures with complex intersections where it can be challenging or impossible to mesh the fractures and rock matrix. In this context, the extra dimensions of COMSOL can be very handy when the matrix has low permeability and transport is diffusion dominated. 

This post shows an example of these capabilities.

Model description
==============
A 3D fractured carbonated media formed by calcite with a constant circulation of groundwater that contains magnesium chloride is considered. In this system, magnesium-rich groundwater flows through the fractures leading to calcite dissolution and eventually dolomite formation. The fracture system is based on a discrete fracture network (DFN) formed by 3,531 hexagonal fractures inside a cube of 200 meters of length centered at origin (**Figure 2**). The hydraulic properties of the fractures (hydraulic conductivity, aperture and storativity) are spatially heterogeneous.

<figure className="image">
      <StrapiImage
        src="/uploads/icp_extradims_2_ffa248334a.png"  className="mx-auto" alt=""
      />
<figcaption>
<b>Figure 2</b>. Finite element mesh used for the application test. The grid consists of 240,721 triangular elements.
</figcaption>
</figure>

The chemical composition for the initial and boundary waters considered is illustrated in **Table 1**. The matrix is assumed to initially contain 2 x10<sup>-4</sup> moles/kg<sub>medium</sub> of calcite. In this system, transport is dominated by advection through the fractures. The travel time to through the materials is large enough to assume local chemical equilibria and hence the dissolution/precipitation of calcite and dolomite is assumed to occur in equilibrium. 

<figure className="image">
      <StrapiImage
        src="/uploads/icp_extradims_table_1_46a58d661f.png"  className="mx-auto" alt=""
      />
<figcaption>
<b>Table 1</b>. Solute concentrations for the initial conditions and the inlet of the fracture used in the calculations.
</figcaption>
</figure>


Due to the complexity of the fracture network, the matrix cannot be modelled explicitly, and then it is represented as an extra-dimension by considering a characteristic length of 1 m with one finite element (two nodes). Thus, each node of the fracture is connected to a linear element of the extra dimension according to the scheme of the Figure 1. 
Regarding the boundary conditions, a prescribed hydraulic head (Dirichlet boundary condition) is imposed along the fractures of the east boundary (h = 1 m) and at the west boundary (h = 0 m). The rest of boundaries are assumed as no flow of both solute and water. The groundwater flow is solved to reach the steady state solution. The reactive transport simulation covers a total simulation time of 210 years.

Results
======
Numerical results from the flow simulation show a groundwater gradient from east to west which is focalized on two preferential paths: one in the upper northern part and the other in the lower Southern part (**Figure 3**). These paths are mainly controlled by the largest and most connected structures. The rest of the fractures present lower flow velocities because they have small transmissivities, they are not well-connected or are even disconnected with the two main set of fractures.

<figure className="image">
<StrapiVideo width="725" height="395" src="/uploads/i_CP_extradim_chloride_tracer_8d67d0dc45.mp4" type="video/mp4"/>
  <figcaption>
<b>Figure 3</b>. Normalized chloride distribution in the fractures at the end of the simulation. Grey lines show the finite element mesh.
</figcaption>
</figure>

**Figure 3** shows the concentration of chloride in the fracture-matrix system. Numerical results also show the presence of two preferential paths for solute transport. Thus, at the end of the simulation the chloride-magnesium plume spreads mainly along the upper north part and at the bottom. Also, after 200 years of simulation, the chloride concentration in the matrix at 0.75 meters form the fractures is lower than half of the concentration entering through the boundary (**Figure 4**), indicating a strong retardation effect of matrix diffusion processes.

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      <StrapiImage
        src="/uploads/icp_extradims_5_950bc98ef1.png"  className="mx-auto" alt=""
      />
<figcaption>
<b>Figure 4</b>. Normalized chloride distribution at the end of the simulation for the fractures (left) and the matrix at 0.25 meters of the fractures (centre) and 0.75 meters of the fractures (right).
</figcaption>
</figure>

Reactive transport results show the progressive replacement of calcite by dolomite due to the movement of the enriched chloride-magnesium plume (**Figure 5** and **Figure 6**). Although the incoming water is initially undersaturated in dolomite, the mixing between the boundary water and the initial water in the matrix leads to oversaturation of this mineral at the front of the magnesium-rich plume. Note that dolomite precipitation occurs mainly at a distance of 0.25 m from the contact between matrix and fractures, and only a small amount of dolomite precipitates along the fractures (**Figure 5**). Numerical results also demonstrated that in some areas once calcite is depleted, mixing induces the dissolution of dolomite.

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      <StrapiImage
        src="/uploads/icp_extradims_6_dacbf06589.png"  className="mx-auto" alt=""
      />
<figcaption>
<b>Figure 5</b>. Concentration of calcite (bottom row) and dolomite (upper row) at the end of the simulation for the fractures (left) and the matrix at 0.25 meters of the fractures (centre) and 0.75 meters of the fractures (right).
</figcaption>
</figure>

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<StrapiVideo width="725" height="395" src="/uploads/i_CP_extradim_calcite_dolomite_904af3a615.mp4" type="video/mp4"/>
  <figcaption>
<b>Figure 6</b>. Animation showing the concentration of calcite, tracer and dolomite at the end of the simulation for the fractures.
</figcaption>
</figure>

Summary and conclusions
===================

This example introduces one of the newest capabilities of iCP, the use of extra dimensions. The results show how iCP can deal with complex discrete fracture networks while accounting for the effect of the rock matrix, which is included as an extra dimension. This setup accounts for the diffusion of chemical species from the fractures to the matrix and vice versa and the diffusion of chemical species through the matrix considering geochemical reactions. This example shows that the use of extra dimension is an efficient way to include matrix diffusion processes in complex geometries including DFNs with thousands of fractures. It should be noted, however, that the extra dimension approach can be applied only when the permeability of the matrix is very low and transport is governed by diffusion. 

If you want to know more about the new capabilities of iCP, you can check out <a href="/post/i-cp-v2-0-release/">this post</a>.






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One of the several improvements and capabilities included in iCP 2.0 is the possibility to add extra dimensions to your reactive transport models

Introducing the new extra dimension capabilities available in iCP 2.0

[iCP](/technology/interface-comsol-phreeqc/) (interface Comsol – PhreeqC) is a powerful and flexible reactive transport modelling software developed at Amphos 21 that can be used to simulate a wide variety of geochemical systems in the fields of nuclear waste management, carbon capture and storage, and mining.

The iCP Symposium to be held on November 10th 2021 is an excellent chance to learn more about the capabilities of iCP. Expert users will share their innovative work carried out with this tool and will showcase the different applications it can be used for. The new features added in iCP 2.0, such as [extra dimensions](/post/introducing-the-new-extra-dimension-capabilities-available-in-i-cp-2-0/)  and mechanical modelling, will also be covered in this Symposium.

You can check out the program below and [register](https://www.amphos21.com/event/icp-symposium/) for free now!

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The iCP Symposium to be held on November 10th 2021 is an excellent chance to learn more about the capabilities of iCP. Expert users will share their innovative work...

iCP Symposium 2021

Motivation
=========
In civil engineering, the design of concrete structures needs to consider durability and long-term performance issues more than ever if sustainability is sought. The mechanical performance of concrete structures can be severely affected by the chemical interaction between concrete and the environment. These degradation processes must be accounted for to properly predict the long-term performance of structures during their service life. Accounting for such chemo-mechanical couplings requires robust and efficient numerical tools based on sound knowledge about how to conceptualize such couplings.

In this context, [iCP version 2.0](/post/i-cp-v2-0-release/) offers the possibility of fully coupling chemical (C) and mechanical (M) processes (i.e., C &rarr; M and M &rarr; C) in reactive transport simulations. In this blog post, we show how to simulate the deformation of a concrete sample under the simultaneous action of chemical degradation and mechanical loading using iCP (Nardi et al., 2014).

Model description
==============
Experimental data from Camps (2008) on compression creep tests of concrete samples locally subjected to a 6 M ammonium nitrate solution (NH4NO3) is simulated with a coupled chemo-mechanical model. Sample geometry, boundary conditions and deformation results are summarized in Figure 1. Ammonium nitrate solutions have been used in experiments of concrete leaching in the past because the attack resembles that with pure water but with a kinetic rate which is up to 200 times faster for high enough NH4NO3 concentrations (e.g. Carde et al., 1996). Ammonium nitrate causes dissolution of cement-based materials through the reaction between ammonium nitrate and calcium hydroxide in the cement paste. The reaction is expressed in equation 1.

$$
\tag*{[Eq. 1]}

2{\rm NH}_4{\rm NO}_3\ +\ Ca\left(OH\right)_2\ \rightarrow\ Ca\left({\rm NO}_3\right)_2\ +\ 2{\rm NH}_3\ +\ 2H_2O

$$


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  <StrapiImage className="mx-auto"  src="/uploads/chemo_mechanical_1_765f0e5389.png" alt=""/>
  <figcaption><b>Figure 1</b>. Evolution of longitudinal strains (left) and geometry and loads (right) for a compression creep test of CEM VF concrete sample locally subject to ammonium nitrate leaching. Data extracted from Hu et al. (2014).</figcaption>
</figure>

Following the experimental setup, the model couples reactive transport (RT) processes under water-saturated and isothermal conditions with a solid mechanics model. However, variably saturated and non-isothermal conditions could be easily added in a more general case. The chemical composition of the concrete sample (made with CEM V), its porosity (0.11), and the aggregate volume fraction (0.64) are defined from the data given in Hu et al. (2014). Solute transport is simulated by Fickian diffusion with a single pore diffusivity for all dissolved species to maintain electroneutrality. The effective diffusion coefficient of concrete is modelled as a function of porosity and mechanical damage. The influence of damage is included as an S-shape function (equation 2; Figure 2) following Gérard et al. (1998). The value of the diffusion coefficient in the absence of chemical attack ($D_{e,0}$) is fixed to 1.0·10<sup>-12</sup> m<sup>2</sup>/s, while $D_{max}$ is the diffusivity of a completely cracked material (1.0·10<sup>-10</sup> m<sup>2</sup>/s). n and $d_{cr}$ are model parameters ($n = 4$, $d_{cr} = 0.9$) and d_m is the mechanical damage variable. A tailor-made simple mechanical damage model is implemented for this test. A scalar damage value based on axial compressive strain of the sample is used (equation 3). The current axial strain ($\varepsilon$) is weighed by a strain threshold value ($\varepsilon_0 = 8.7·10-4$). It is noted that in this approach we compute $d_m$ as a post-process of the mechanical behaviour, without any impact on the mechanical constitutive model (equation 3). More realistic damage models can also be implemented in Comsol (as demonstrated here) but the one used here is enough to demonstrate the coupled C-M behaviour.

$$
\tag*{[Eq. 2]}

D_e=D_{e,0}+D_{max}[1-\frac{1}{1+\left(\frac{d_m}{d_{cr}}\right)^n}]

$$

$$
\tag*{[Eq. 3]}

d_m=\frac{\varepsilon-\varepsilon_0}{\varepsilon_0}

$$

Concrete is modelled as a linear elastic material but introducing the effect of chemical damage, $d_c$, as in classical damage mechanics theory (Kachanov, 1986). This simple approach is defined by a Young’s modulus of the intact material, $E_0$, of 43 GPa and a Poisson’s ratio of 0.27. For the sake of simplicity, no creep model is accounted for, which implies that time-dependent deformations are only considered in the model as a result of chemical damage. The chemical damage due to leaching is considered as a scalar variable and affects the Young’s modulus ($E$) as a function of calcium content in the concrete solid skeleton, $Ca_s$ (Gérard et al., 1998; Hu et al., 2014; Figure 2):

$$
\tag*{[Eq. 4]}

\mathbf{E}=\mathbf{E}_\mathbf{0}·\left(1-d_c\right)\text{; with } d_c=d_{c,max}·(1-e^{Ca_s-Ca_{s,0}}) 

$$







<figure className="image">
  <StrapiImage className="mx-auto"  src="/uploads/chemo_mechanical_2_cb50bb336f.png" alt=""/>
  <figcaption><b>Figure 2</b>. Diffusion coefficient (m<sup>2</sup>/s) as a function of mechanical damage (1) as defined in equation 2 (left) and chemical damage variable (1) as a function of the amount of solid Ca content (mol/l<sub>medium</sub>) as defined in equation 4 (blue line) and comparison with experimental results (dots) after Gérard et al., 1998 (right).
</figcaption>
</figure>

Results
=======

The mechanical load applied to the sample is constant and equal to 37.6 MPa, resulting in an instantaneous deformation. If no chemical attack is considered, no further deformations are observed (recall that no creep is considered for simplicity). In contrast, when the exposure to ammonium nitrate is modelled, the mechanical properties of the concrete sample are gradually reduced with solid calcium content being leached. In the latter case, deformations gradually increase in time as the material stiffness decreases (Figure 3-right).

The impact of mechanics on the chemical scheme is shown when comparing the results in the centre of Figure 3 (no coupling of damage on $D_e$) and those on the right (fully coupled model). If this coupling is disregarded, Ca content in the solid skeleton decreases with a lower rate. The temporal evolution of effective diffusion coefficient in the sample is shown in Figure 4 together with the distribution of mechanical damage variable.

Model results are in relatively good agreement with experimental ones (Figure 5), despite the simplicity of the coupled chemo-mechanical model. Deformation after 500 days is doubled for the sample exposed to ammonium nitrate. 



<figure className="image">
  <StrapiVideo width="725" height="395" src="/uploads/chemo_mechanical_merged_Ca_s_0bba68ed46.mp4" type="video/mp4" />
  <figcaption><b>Figure 3</b>. Solid Ca content evolution with time (coloured scale) and sample displacements (geometrical deformation) for the model without (left) and with chemical damage considering (right) or not (centre) the dependence of $D_e$ on mechanical damage.</figcaption>
</figure>

<figure className="image">
  <StrapiVideo width="725" height="395" src="/uploads/chemo_mechanical_d_m_and_Deff_3_D_c0ae814f82.mp4" type="video/mp4" />
  <figcaption><b>Figure 4</b>. Effective diffusion coefficient (log<sub>10</sub>(m<sup>2</sup>/s)) evolution with time (left) as a consequence of mechanical damage evolution (right). </figcaption>
</figure>


<figure className="image">
  <StrapiImage className="mx-auto"  src="/uploads/chemo_mechanical_3_178aa24330.png" alt=""/>
  <figcaption><b>Figure 5</b>. Modelled (in blue) and experimental (in grey) axial strain (10<sup>-6</sup>) evolution results. 
</figcaption>
</figure>

Concluding remarks 
==============
The performance of concrete and other cementitious materials under the simultaneous action of mechanical loading and chemical degradation (ammonium nitrate attack) can be properly modelled by means of fully coupled chemo-mechanical models in iCP version 2.0. A two-way coupled scheme between chemistry to mechanics has been implemented. The presented example shows the capabilities of iCP v2.0 to handle CM fully coupled processes. 

References
==============

Camps G, 2008. **Etude des interactions chemo-mécaniques pour la simulation du cycle de vie d’un élément de stockage en béton**. Ph.D thesis, Paul Sabatier Univ. Toulouse, Toulouse, France (in French).

Carde C, François R, Torrenti J M, 1996. **Leaching of both calcium hydroxyde and C-S-H from cement paste: modeling the mechanical behaviour**, Cement and Concrete Research, 28 (6), 1257-1268. https://doi.org/10.1016/0008-8846(96)00095-6

Gérard B, Pijaudier-Cabot G, Laborderie C, 1998. **Coupled diffusion-damage modelling and the implications on failure due to strain localization**. International Journal of Solids and Structures 35, 4107-4120. https://doi.org/10.1016/S0020-7683(97)00304-1

Kachanov L M, 1986. **Introduction to Continuum Damage Mechanics**. M. Nijhoff, Dordrecht, Boston, MA. https://doi.org/10.1007/978-94-017-1957-5

Nardi A, Idiart A, Trinchero P, de Vries L M, Molinero J, 2014. **Interface COMSOL-PHREQC (iCP), an efficient numerical framework for the solution of coupled multiphysics and geochemistry**. Computers & Geosciences 69, 10-21. https://doi.org/10.1016/j.cageo.2014.04.011

Hu D, Zhou H, Zhang F, Shao J, 2014. Modeling of short- and long-term chemomechanical coupling behavior of cement-based materials. ASCE, Journal of Engineering Mechanics, 206-218. https://doi.org/10.1061/(ASCE)EM.1943-7889.0000639


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 In this blog post, we show how to simulate the deformation of a concrete sample under the simultaneous action of chemical degradation and mechanical loading using iCP.

Chemo-mechanical coupled behaviour of cement-based materials

[iCP](/technology/interface-comsol-phreeqc/) (interface Comsol–PhreeqC) is a powerful and flexible reactive transport modelling software developed at Amphos 21 that can be used to simulate a wide variety geochemical systems in geoscientific applications, such as geological disposal of radioactive waste, carbon capture and storage, or mining.

Amphos 21, with the collaboration of [Barcelona Science](https://barcelonascience.com/), is organizing an **online iCP Training course on 8-10th November 2022**.

This three-day course will cover the following topics:

* **1st day (8/11/2022):**

    * iCP overview and installation
    *  Introduction to Reactive Transport Modelling
    * Introduction to Comsol, focus on flow and solute transport in porous media
    * Hands-on iCP example: Cation exchange, part I

* **2nd day (9/11/2022):**

    * Introduction to PhreeqC
    * Hands-on iCP example: Cation exchange, part II
    * Hands-on iCP example: Calcite dissolution

* **3rd day (10/11/2022):**

    * Advanced hands-on iCP example
    * Advanced topics of iCP and on-going developments

The course will be held by expert lecturers in the use of Comsol, PhreeqC and iCP and with vast experience in the application of reactive transport in geosciences:

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<p><b>Jorge Molinero</b> is the Scientific and Technical Director of Amphos 21. He received his PhD in Civil Engineering (University of A Coruña, Spain), and has 20 years of experience working with reactive transport simulations. Before joining AMPHOS 21 he was Assistant and Associate Professor at the Universities of A Coruña, Santiago de Compostela and UPC-Barcelona Tech.
</p>
</div>
</div>

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<p>
<b>Elena Abarca</b> is Group Manager in hydrogeology and reactive transport modelling at Amphos 21. She holds a PhD in Hydrogeology by the UPC – Barcelona Tech. Her work focusses in numerical modelling of groundwater flow and transport of (conservative and reactive) contaminants in porous media. Before joining Amphos 21, she was a Post-Doctoral Research Associate at the Auburn University (US) and the Massachusetts Institute of Technology (US).
</p>
</div>
</div>

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<p>
<b>Andrés Idiart</b> is a Civil Engineer with a PhD in Solid Mechanics and works as a Group Manager in engineering materials at Amphos 21. Andrés fields of expertise include geomechanics and the coupling between multiphysics and geochemistry.
</p>
</div>
</div>

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<p>
<b>Emilie Coene</b> is a consultant and iCP developer at Amphos 21 with a Chemical Engineering degree and a Master in Modelling for Science and Engineering. She is an expert in numerical model development and application. As a consultant at Amphos 21, she has been involved in several projects related with nuclear waste management, oil & gas and mining that involved reactive transport and multiphase-flow models.
</p>
</div>
</div>

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<p>
<b>Marcelo Laviña</b> is a consultant of the Modelling Solutions team at Amphos 21 Barcelona since 2016. He develops geomechanical and reactive transport models, specialising in the coupling of hydro-chemo-mechanical (HCM) processes in porous media. Marcelo obtained his Civil Engineering degree and his Master of Science degree from the Technical University of Madrid (UPM). During his last year at UPM, he was granted by the Hydraulics Department of the Civil Engineering School at UPM to perform research related with the modelling of hydro-geomechanical processes in fractured media
</p>
</div>
</div>

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<p>
<b>Diego Sampietro</b> is a consultant in the Modelling Solutions team at Amphos 21 since 2014. He is a Geologist with a postgraduate course in Hydrogeology and a master’s degree in mathematical modelling. Currently, he is doing a PhD thesis about reactive transport modelling in fractured systems. His main field of expertise includes the modelling of hydro-chemical processes in porous and fractured media. He is an advanced user of several modelling softwares such as Comsol Multiphysics or iCP.
</p>
</div>
</div>


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    <p>
<b>Albert Nardi</b> is CEO at Barcelona Science and Group Manager in Hydroinformatics, Software and Data Science at Amphos 21. He holds an Industrial Engineering degree and a Master in Hydrogeology. He is an expert in numerical modelling and software development. He is one of the main developers of iCP and <a href="https://gibbsstudio.io/">GibbsStudio</a>.
    </p>
  </div>
</div>

The cost of the course is:
* 1,200€ Early Bird Registration (before 30th of September) 
* 1,400€ Standard (before 31st of October). 

The course includes the lectures, lecture material, one permanent R&D license per participant and a 2h support session. The support session is personalized for each participant and can be used to work on a model of interest within the following 15 days after the course.


Course registration is open until the 31st of October 2022. If you have any questions or doubts, please contact techlabs@amphos21.com. 

[Course registration](https://en.amphos21.com/event/icp-basics-course-november-2022/) (Available until the 31st of October 2022) 

We look forward to seeing you in November!


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Amphos 21 is organizing an online iCP Training course on 8-10th November 2022.

iCP Training Course, 8-10th November 2022

We are happy to announce the release of iCP 2.1. This version has mainly focused on ensuring the compatibility with Comsol 6.0 and upgrading the software to Java 11.

You can download iCP 2.1 <a href="https://files.amphos21.com/s/iCP-v2_1">here</a > and you can request a license by filling in the <a href="/form/icp-license-request/">license form </a>.

This version also incorporates the following changes:

 - The iCP Module has been fixed to be compatible with Comsol 5.6 and later versions.
 - Temporal files saved during iCP runs may result in large unused files stored in disk if the simulation fails. These temporal files are not stored anymore.
 - Improve numerical manager capabilities through the <i>ignorePhreeqcErrorAndUsePreviousValue</i> option.
 - Upgrade Phreeqc to v3.7.3
 - Fix error with diffusion terms when using Transport of Diluted Species.
 - Enable restart when the time step is zero.

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We are happy to announce the release of iCP 2.1.

iCP 2.1 Release

<a href="/technology/interface-comsol-phreeqc/">iCP</a> is an interface that couples COMSOL Multiphysics and PHREEQC. It is a powerful and flexible tool for reactive transport modelling in porous and fractured media developed by Amphos 21. iCP is used for a wide range of geoscientific applications that include geochemistry, with prominent case studies about geological disposal of radioactive waste, carbon capture and storage, and mining. Complex thermo-hydro-mechanical processes can be flexibly coupled with geochemistry in a single modelling framework. 

Amphos 21 is happy to announce the 2024 **fully online iCP Training** course that will be held between 11th and 14th November 2024 from 9:00 to 13:15 Spanish Time (UTC/GMT +1 hour).

The **16 hours online course** give you the tools to get started in reactive transport modelling with iCP, covering the following topics:

* **1st day (9/11/2024):**

    * iCP overview and installation
    * Introduction to PHREEQC, a geochemical simulator from USGS (USA), with practical examples
    * Introduction to COMSOL Multiphysics, focusing on flow and solute transport in porous media, with practical examples

* **2nd day (10/11/2024):**
    * Introduction to Reactive Transport Modelling
    * First Hands-on iCP example: Cation exchange

* **3rd day (11/11/2024):**
    * Second Hands-on iCP example: Calcite dissolution

* **4th day (12/11/2024):**
    * Advanced hands-on iCP example: thermo-hydro-geochemical couplings
    * Advanced applications of iCP, case studies, and on-going developments

After the course, you will be able to:
* Understand the fundamentals of reactive transport modelling and how to implement them in iCP,
* Work independently with the most important features of model setup in iCP,
* Leverage many of the advanced features and powerful functionalities of COMSOL and how to use them in combination with iCP,
* Setup your own geochemical systems in PHREEQC, a powerful geochemical simulator,
* Implement practical examples of flow and solute transport in porous media using COMSOL Multiphysics.


The course will be held by experts in the use of COMSOL, PHREEQC and iCP, with vast experience in the application of reactive transport modelling in geosciences:

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    <p>
<b>Albert Nardi</b> is is Project Manager and Senior Consultant in Hydroinformatics, Software and Data Science at the Department of Digital Solutions of Amphos 21. He holds an Industrial Engineering degree and a Master in Hydrogeology from UPC (Spain). He is an expert in numerical modelling and software development. He is in charge of the development team of <a href="/technology/interface-comsol-phreeqc/">iCP</a> and also <a href="https://gibbsstudio.io/">GibbsStudio</a>.
    </p>
  </div>
</div>


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<p>
<b>Elena Abarca</b> leads the Department of Water Resources and Environment at Amphos 21. She holds a PhD in Hydrogeology from the UPC – Barcelona Tech. Her work focusses in numerical modelling of groundwater flow and reactive transport of contaminants in porous and fractured media. Before joining Amphos 21, she was a Post-Doctoral Research Associate at the Auburn University (USA) and the Massachusetts Institute of Technology (MIT, USA).
</p>
</div>
</div>

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<p>
<b>Andrés Idiart</b> is the Director of Operations at Amphos 21. He holds Civil Engineer with a PhD in Civil Engineering and Solid Mechanics from the UPC – Barcelona Tech and a post-doc in reactive transport modelling as a Marie Curie Research Fellow from the EDF-spin-off company Oxand S.A., in France. His fields of expertise include geomechanics and the coupling between multiphysics and geochemistry.
</p>
</div>
</div>

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<p>
<b>Emilie Coene</b> is a Senior Consultant and iCP developer at Amphos 21, with a Chemical Engineering degree and a Master in Modelling for Science and Engineering from the UAB, Spain. She is an expert in numerical model development and application using iCP. She has been involved in numerous projects related with reactive transport and multiphase-flow models for geological disposal of radioactive waste, carbon capture and storage, and mining.
</p>
</div>
</div>

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<p>
<b>Marcelo Laviña</b> is a Senior Consultant at Amphos 21. He obtained his Civil Engineering degree and Master of Science degrees from the Technical University of Madrid (UPM, Spain). His research at the Hydraulics Department of UPM was related with the modelling of hydro-geomechanical processes in fractured media. At Amphos 21, he is an expert in the development and implementation of coupled hydro-chemo-mechanical models in porous media for geological disposal of radioactive waste applications. 
</p>
</div>
</div>

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<b>Diego Sampietro</b> is a Senior Consultant at Amphos 21. He is a Geologist from the University of Zaragoza (Spain) with a post-graduate course in Hydrogeology from UPC (Spain) and a Master’s degree in mathematical modelling from UAB (Spain). He is an expert in reactive transport modelling in fractured systems with iCP. As a Senior Consultant, he has been involved in several projects related with geological disposal of radioactive waste studies in different countries, such as Sweden, Finland, Spain, or Japan.
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<b>Ersan Demirer</b> is a Senior Consultant at Amphos 21 since 2021. He has a PhD in Mechanical Engineering from the Georgia Institute of Technology, focusing on computational fluid dynamics and particularly constructing numerical models to capture fluid-structure interaction phenomena. He is an expert in numerical modelling of transport phenomena, as well as computational mechanics and optimization methods. As a consultant at Amphos 21, he has been involved in nuclear waste management and Oil and Gas projects involving numerical modelling of multiphase flow and reactive transport in porous media such as concrete, clay, or carbonate rocks.
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The cost of the course is:
* 1,500€ Early Bird Registration (before 30th of September 2024) 
* 1,700€ Standard (after 30th of September 2024).

The course includes the lectures, lecture material and one permanent R&D license per participant.

Course registration form is open until October 27th 2024 or until the maximum of registered participants is attained.

[Go to course registration form](/form/icp-course-registration-request)

If you have recently acquired an iCP license, you qualify for a discount on the course. Contact us for more info.  

For any questions or doubts, please contact us at techlabs@amphos21.com. 

We look forward to seeing you in November!



Icp