DECOVALEX

DEvelopment of COupled models and their VALidation against EXperiments

Stage 3 (Lasgit): the Large scale gas injection test at the -420 m level in Äspö HRL. More Information »

The Second International DECOVALEX Coupled Processes Symposium will be held on November 14-16, 2023. More Information »

Example modeling task from DECOVALEX III: The Drift Scale Test (DST) experiment, conducted by DOE: A set of 9 large heaters and 50 smaller “wing” heaters set in unsaturated tuff; no backfill. Monitoring in the rock includes measurements not only of temperatures and displacement, but also saturation, effective hydraulic conductivity, and water samples for chemical and isotopic studies.

Coupled THMC evolution of single fractures as considered by Task C1 in DECOVALEX-2015

ALC experiment by Andra, being considered under Task E of DECOVALEX-2019 as part of a blind prediction exercise

The HE-E (left) and EBS Experiment (right) considered as part of Task B1 in DECOVALEX-2015

The DECOVALEX project is an international research and model comparison collaboration, initiated in 1992, for advancing the understanding and modeling of coupled thermo-hydro-mechanical-chemical (THMC) processes in geological systems. Prediction of these coupled effects is an essential part of the performance and safety assessment of geologic disposal systems for radioactive waste and spent nuclear fuel, and also for a range of sub-surface engineering activities. The project has been conducted by research teams supported by a large number of radioactive-waste-management organizations and regulatory authorities. Research teams work collaboratively on selected modeling cases, followed by comparative assessment of model results. This work has yielded in-depth knowledge of coupled THM and THMC processes associated with nuclear waste repositories and wider geo-engineering applications, as well as the suitability of numerical simulation models for quantitative analysis. More »

DECOVALEX-2023: The Current Project Phase (2020-2023)

Brief Summary

DECOVALEX-2023 is the current and 8th project phase and runs from 2020 through 2023. Modeling teams from 17 international partner organizations participate in the comparative evaluation of seven modeling tasks involving complex field and/or laboratory experiments in the UK, Switzerland, Japan, France and Sweden. Together, these tasks address a wide range of relevant issues related to engineered and natural system behavior in argillaceous and crystalline host rocks.

Task A

Layout of the CRQ in-situ experiment and cross-section plane at 15 m from the GCS drift wall where a fracture is expected.

Task A addresses both areas related to the fluid pressurization within the COx and its resulting fracturing. It will also contribute to a robustness demonstration that these processes will not occur at the repository scale. More »

Task B

Stage 3 (Lasgit): the Large scale gas injection test at the -420 m level in Äspö HRL.

Several concerns were raised in Task A D-2019 as some key features in the modelling of advective gas were still unclear. With these concerns in mind, development of new numerical representations for the quantitative treatment of gas in clay-based repository systems are therefore required, and are the primary focus of Task B under DECOVALEX-2023. More »

Task C

Figure 1: Schematic diagram of the FE tunnel.

The full-scale emplacement experiment (FE experiment) at the Mont Terri Underground Rock Laboratory was designed to replicate the emplacement tunnel of Nagra’s reference repository design at 1:1 scale. The focus will be to understand pore pressure development in the Opalinus Clay and how this is affected by heating, engineering factors (e.g. shotcrete, tunnel shape) and damage due to tunnel construction and thermal effects. More »

Task D

Schematic view of the Horonobe full scale in-situ EBS experiment

Full scale in situ Engineered Barrier System (EBS) experiments have been addressed in several phases of the DECOVALEX project where water infiltration into the buffer material after the emplacement was analyzed. The task being conducted here focuses on the incorporation of such buffer material density changes into the analysis codes. More »

Task E

Figure 1. BATS heated array and data acquisition systems

The primary Task E objective is to predict and quantify the importance of coupled THMC processes relating to the availability of heating, mechanical deformation, and water to flow into heated excavations in bedded salt. More »

Task F

Figure 2. Example of a flow and transport model domain with generic repository in fractured crystalline rock.

The primary objectives of Task F are to build confidence in the models, methods, and software used for performance assessment (PA) of deep geologic repositories, to bring to the fore additional research and development needed to improve PA methodologies, and to cultivate awareness of international PA practices among participating countries and teams. More »

Task G

The emphasis of this task is at the laboratory scale, using well-designed experiments to link micro-scale THM(C) effects acting on fracture surfaces and asperity contacts with emergent fracture properties such as permeability. More »

Current Partner Organizations

Logo	Link	Organization
	link	ANDRA National Radioactive Waste Management Agency France
	link	BASE The Federal Office for the Safety of Nuclear Waste Management Germany
	link	BGE Federal Company for Radioactive Waste Disposal Germany
	link	BGR Federal Institute for Geosciences and Natural Resources Germany
	link	CAS State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences China
	link	CNSC Canadian Nuclear Safety Commission Canada
	link	COVRA Centrale Organisatie Voor Radioactief Afval Netherlands
	link	DOE Department of Energy USA
	link	ENRESA Empresa Nacional de Residuos Radiactivos Spain
	link	ENSI Swiss Federal Nuclear Safety Inspectorate Switzerland
	link	JAEA Japan Atomic Energy Agency Japan
	link	KAERI Korea Atomic Energy Research Institute Republic of Korea
	link	NWMO Nuclear Waste Management Organization Canada
	link	RWM Radioactive Waste Management UK
	link	SSM Swedish Radiation Safety Authority Sweden
	link	SURAO Radioactive Waste Repository Authority Czech Republic
	link	Taipower Taiwan Power Company Taiwan

DECOVALEX

DEvelopment of COupled models and their VALidation against EXperiments

DECOVALEX-2023: The Current Project Phase (2020-2023)

Current Partner Organizations

DECOVALEX 2023

Past DECOVALEX Phases

Contacts

DECOVALEX Chairman

DECOVALEX Secretariat