Geochemical & Reactive Transport Modelling for Geological Disposal training

Training aims
The training aims at enlarging knowledge and expertise in geochemical and coupled reactive transport modelling in the framework of disposal of radioactive waste with the focus on geological disposal. The theoretical basis will be enhanced by lectures on (i) principles of geochemical and reactive transport modelling, (ii) their applications for processes and evolution of materials in a geological disposal (cementitious materials, glass, steel, clay, granite) (iii) speciation and migration of radionuclides, and (iv) advanced topics related to uncertainty and machine learning. Practical skills will be improved by computer sessions in which participants will use available software to implement and analyze models for calculating properties and evolution of materials and speciation of radionuclides.

Detailed description
Lectures on different topics related to geochemical and reactive transport modelling (provisional list)

Modelling geochemical systems – Thermodynamics, databases, reaction progress
Modelling slow processes (corrosion, dissolution, degradation)
Modelling properties and geochemistry of cementitious systems
Geochemistry of the host rock and natural barrier materials: Pore water, mineralogy, matrix-fracture
Speciation of radionuclides
Sorption of radionuclides
Reactive transport modelling
Uncertainty and sensitivity analysis
Use of model abstraction – surrogate modelling – machine learning in geochemical and reactive transport modelling

Hands-on on implementation of geochemical and reactive transport modelling (about 10 sessions). Based on two applications linked to ACED and FUTURE and are used in DONUT for benchmarking, participants will be trained in defining a conceptual model and implementing it in a geochemical and reactive transport code. The participants can chose from one of 3 codes based on GEMS, ORCHESTRA and PHREEQC – it is advisable to join the same code during the whole training. We will strive to have an equal distribution of the participants between the three codes. The two applications are:

Cementitious materials (ordinary Portland cement): database, hardening, geochemistry and other properties, chemical degradation/alteration, leaching or carbonation
Uranium sorption on clay materials: database, speciation, sorption to clay minerals, migration

Demonstration of other codes: during short lectures, an introduction to a number of other geochemical and coupled reactive transport codes that are used in the framework of radioactive waste disposal. Examples are CRUNCH, MIN3P, HYTIC/CHESS, CORE, OPENGEOSYS, OpenFOAM-PHREEQC, iCP (specific choices will depend on the availability of presenters)