Earth Sciences Division (ESD) Department of Energy (DOE) Lawrence Berkeley National Laboratory (LBNL)


Development of Coupled Models and their Validation Against Experiments in Nuclear Waste Isolation (DECOVALEX)

The DECOVALEX Project is a unique international research collaboration for advancing the understanding and mathematical modeling of coupled thermo-hydro-mechanical (THM) and thermo-hydro-chemical (THC) processes in geological systems. DECOVALEX is an acronym for “Development of Coupled Models and their Validation against Experiments”. Starting in 1992, the project has made important progress and played a key role in the development of numerical modeling of coupled processes in fractured rocks and buffer/backfill materials. The project has been conducted by research teams supported by a large number of radioactive-waste-management organizations and regulatory authorities, including those of Canada, China, Finland, France, Japan, Germany, Spain, Sweden, UK, South Korea, Czech Republic, and the USA. Through this project, in-depth knowledge has been gained of coupled THM and THMC processes associated with nuclear waste repositories, as well as numerical simulation models for their quantitative analysis. The knowledge accumulated from this project, in the form of a large number of research reports and international journal and conference papers in the open literature, has been applied effectively in the implementation and review of national radioactive-waste-management programs in the participating countries.

The DECOVALEX Project is typically conducted in separate 3-4 year project phases. Each phase features a small number (typically three to six) modeling test cases of importance to radioactive waste disposal. Many test cases are laboratory and field experiments that have been conducted by one of the project partners and are then collectively studied and modeled by DECOVALEX participants. Numerical modeling of these test cases can assist both to interpret the test results and to test the models used. Over the years, a number of large-scale, multiyear field experiments have been studied within the project (e.g., the Kamaishi THM Experiment, FEBEX, and the Yucca Mountain drift-scale heater test). Thus, the project provides access to valuable technical data and expertise to DECOVALEX partner organizations; this is particularly useful in disposal programs that are starting their research on certain disposal or repository environments and have no URLs. DECOVALEX has a modeling focus, but with tight connection to experimental data.

LBNL scientists have participated in various past DECOVALEX phases and several DECOVALEX projects. With DOE/UFD being a partner organization in the ongoing DECOVALEX phase (start in 2012), referred to as DECOVALEX–2015, LBNL is now working on Task B of the current DECOVALEX project. The three modeling tasks being conducted in DECOVALEX–2015 are:

  • Task A: Sealex experiment at Tournemire (led by IRSN)
  • Task B: Heater tests at Mont Terri and Honorobe (led by UPC and JAEA)
  • Task C: Bedrichov tunnel flow and transport plus single fracture THMC (RAWRA and Imperial College)

Read more (DECOVALEX publications) »

For more information, please contact:

Jens Birkholzer
Head, Nuclear Energy and Waste Program
Earth Sciences Division
Phone: 510-486-7134
Fax: 510-486-5686