Understanding natural groundwater quality patterns, quantifying groundwater pollution and
assessing the performance of waste disposal facilities require modeling tools accounting for water flow,
transport of heat and dissolved species as well as their complex interactions with solid and gaseous
phases. Here we present, CORE2D V4, a COde for modeling partly or fully saturated water flow, heat
transport and multicomponent REactive solute transport under both local chemical equilibrium and
kinetic conditions. It can handle abiotic reactions including acid-base, aqueous complexation, redox,
mineral dissolution/precipitation, gas dissolution/exsolution, ion exchange and sorption reactions (linear
Kd, Freundlich and Langmuir isotherms, and surface complexation using constant capacitance, diffuse
layer and triple layer models) and microbial processes. Hydraulic parameters may change in time due to
mineral precipitation/dissolution reactions. A sequential iterative approach is used for the numerical
solution of coupled reactive transport equations. The capabilities of CORE2D V4 are illustrated with six
selected applications involving: 1) A laboratory concrete degradation experiment, 2) The long-term
geochemical evolution of the near field of a High Level Radioactive Waste (HLW) repository in clay,
3) Cation exchange in a physically and geochemically heterogeneous medium, 4) An experiment of
CO2 injection in the vadose zone, 5) The prediction of the water quality of an open pit lake, and 6)
Coupled thermo-hydro-chemical processes of compacted bentonite after FEBEX in situ test.
Keywords: Reactive transport, numerical model, CORE, HLW repository, pit lake, CO2 injection.
