Introduction

The DECOVALEX III project was the third phase of the DECOVALEX project series and operated through the period 1999–2003. It was initiated with two main objectives. The first was the further verification of computer codes, developed or used by the participating member organizations and their research teams, by simulating two large scale in-situ experiments: the FEBEX T‑H‑M experiment in an underground research laboratory (URL), Grimsel, Switzerland, designated as Task 1, and the drift scale heater test at Yucca Mountain, Nevada, USA, designated as Task 2. The second objective was to determine the relevance of THM processes in establishing the safety of a repository by numerical modelling of three benchmark tests (BMTs) to examine the relevance of THM processes to performance and safety assessments: BMT1—the impact of THM processes in the near-field of a hypothetical repository in fractured hard rocks; BMT2—homogenisation and upscaling of hydro-mechanical properties of fractured rocks and their impact on far-field performance and safety assessments; and BMT3—impact of glaciation process on far-field performance and safety assessments. These three BMTs were designated as Task 3.

An additional Task 4 was also organized to present the status at that time of the current understanding of the impacts and treatments of the THM issues on performance assessment (PA) and safety assessment (SA) of nuclear waste repositories, from the views of the Funding organizations of the DECOVALEX project, through compilation of answers to a questionnaire prepared for this purpose.

Also, on September 25, 2000, the European Commission (EC) signed a contract for the FIKW-CT2000-00066 "BENCHPAR" project with a group of European members of the DECOVALEX III project. The BENCHPAR project acronym stands for ´Benchmark Tests and Guidance on Coupled Processes for Performance Assessment of Nuclear Waste Repositories´ and was aimed at improving the understanding of the impact of the thermo-hydro-mechanical (THM) coupled processes on the radioactive waste repository performance and safety assessment. The project had eight principal contractors, all members of the DECOVALEX III project, and four assistant contractors from universities and research organizations. The BENCHPAR project was designed to advance the state-of-the-art via five Work Packages (WPs). WP 1 was to establish a technical auditing methodology for overseeing the modelling work. WPs 2–4 parallelled the three bench mark tests (BMT1–BMT3) in the DECOVALEX III project. A Guidance Document outlining how to include the THM processes in performance assessment (PA) studies was developed in WP 5 which explained the issues concerned and the technical methodology, presented the three demonstration PA modelling studies, and provided guidance for inclusion of the THM components in PA modelling.

The tasks were coordinated by the following coordinators:

  • Task 1by J. Mayor (ENRESA, Spain) and E. Alonso (UPC, Spain);
  • Task 2 by R. Datta (DOE, USA) and L. Jing at the Decovalex III project Secretariat (KTH, Sweden);
  • Task 3-BMT1 by T. S. Nguyen (CNSC, Canada) and L. Jing at the DECOVALEX III project Secretariat (KTH, Sweden);
  • Task 3-BMT2 by J. Andersson (Streamflow AB, Sweden) and L. Knight (Nirex, UK);
  • Task 3-BMT3 by T. Chan (AECL, Canada), R. Christiansson (SKB, Sweden) and L. Jing at the DECOVALEX III project Secretariat (KTH, Sweden); and
  • Task 4 by J. Andersson (Streamflow AB, Sweden).

In total 15 funding organizations participated in DECOVALEX III project:

  • National Agency for Radioactive Waste Management (ANDRA), France;
  • Federal Institute for Geosciences and Natural Resources (BGR), Germany;
  • Commisariat a l’Energi Atomique de Cadarache (CEA), France;
  • Canadian Nuclear Safety Commission (CNSC), Canada;
  • US Department of Energy (DOE), USA;
  • Empresa Nacional de Residoos Radioactivds, S. A. (ENRESA), Spain;
  • European Commission (EU, through the BENCHPAR project);
  • Institute for Protection and Nuclear Safety (IRSN), France;
  • Japan Nuclear Cycle Development Institute (JNC), Japan;
  • United Kingdom Nirex Ltd. (NIREX), UK;
  • Nuclear Regulatory Commission (NRC), USA;
  • Ontario Power Generation (OPG), Canada;
  • Swedish Nuclear Fuel and Waste Management Co. (SKB), Sweden;
  • Swedish Nuclear Power Inspectorate (SKI), Sweden; and
  • Radiation and Nuclear Safety Authority (STUK), Finland.

Table 1 lists all research teams and task distributions.

Table 1. Research team distribution for the Tasks
F.O. Research team Tasks studied
ANDRA INERIS-LAEGO, Ecole des Mines de Nancy, France;
Ecole Polytechnique, G3S, France
Task 1, BMT2;
Task 1.
BGR University of Tuebingen, Germany;
University of Hannover, Germany;
Federal Institute for Geosciences and Natural Resources, Germany.
BMT2;
BMT2;
Task 1.
CEA CEA/DM25/SEMT, France Task 2
CNSC Canadian Nuclear Safety Commission, Canada Task1, BMT2.
DOE Sandia National Laboratory, USA;
Lawrence Berkeley National Laboratory, USA
Task 1;
BMT2.
ENRESA Universidad Politecnica de Catalunya, Spain
Universidad Politecnica de Valencia, Spain
Task 2;
BMT2.
EU (through the BENCHPAR Project) University of Edinburgh, UK;
Royal Institute of Technology, Sweden;
INERIS-LAEGO, Ecole des Mines de Nancy, France;
Universidad Politecnica de Valencia, Spain;
CEA/DM25/SEMT, France;
Chalmers University of Technology, Sweden.
BMT3;
BMT1, BMT2;
BMT2;
BMT1;
BMT1;
BMT3.
IRSN Paris School of Mines, France;
CEA/DM25/SEMT, France.
Task 1;
BMT1.
JNC Tokai Works, JNC, Japan;
Hazama Corporation, Japan;
Kyoto University, Japan.
Task 1, Task 2;
BMT1, BMT2;
BMT1, BMT2.
NIREX University of Birmingham, UK BMT2.
NRC CNWRA, Southwest Research Institute, USA. Task 2
OPG Atomic Energy of Canada, Ltd., Canada. BMT2, BMT3.
SKB Chalmers University of Technology, Sweden;
Clay Technology AB, Sweden.
BMT3;
Task 1.
SKI Lawrence Berkeley National Laboratory, USA;
Royal Institute of Technology (KTH), Sweden.
Task 1;
BMT1, BMT2.
STUK Technical University of Helsinki, Finland;
Uppsala University, Sweden.
Task 1, BMT3;
BMT2.

The following 11 research reports were generated after the completion of the DECOVALEX III project:

  • L. Jing, C.-F. Tsang, J.-C. Mayor, O. Stephansson and F. Kautsky, DECOVALEX III Project: Mathematical models of coupled thermal-hydro-mechanical processes for nuclear waste repositories, executive summary, February 2005, SKI Report 2005:19, Swedish Nuclear Power Inspectorate (SKI), Stockholm, Sweden. ISSN 1104-1374, ISRN SKI-R-05/19-SE.
  • E.E. Alonso and J. Alcoverro, DECOVALEX III Project: Modeling of FEBEX in-situ test. Task 1 final report. February 2005. SKI Report 2005:20, Swedish Nuclear Power Inspectorate (SKI), Stockholm, Sweden. ISSN 1104-1374, ISRN SKI-R-05/20-SE.
  • R. N. Datta, DECOVALEX III Project: Thermal-hydrological modeling of the Yucca Mountain Project Drift Scale Test. Task 2A final report. February 2005. SKI Report 2005:21, Swedish Nuclear Power Inspectorate (SKI), Stockholm, Sweden. ISSN 1104-1374, ISRN SKI-R-05/21-SE.
  • R. N. Datta (ed.), DECOVALEX III Project: Thermal-hydrological modeling of the Yucca Mountain Project Drift Scale Test. Task 2B/2C final report. February 2005. SKI Report 2005:22, Swedish Nuclear Power Inspectorate (SKI), Stockholm, Sweden. ISSN 1104-1374, ISRN SKI-R-05/22-SE.
  • R. N. Datta (ed.), DECOVALEX III Project: Thermal-hydrological modeling of the Yucca Mountain Project Drift Scale Test. Task 2D final report. February 2005. SKI Report 2005:23, Swedish Nuclear Power Inspectorate (SKI), Stockholm, Sweden. ISSN 1104-1374, ISRN SKI-R-05/23-SE.
  • L. Jing and T. S. Nguyen (eds.), DECOVALEX III/BENCHPAR projects: implications of thermal-mechanical coupling on the near-field safety of a nuclear waste repository, Report of BMT1A/WP2. February 2005. SKI Report 2005:24, Swedish Nuclear Power Inspectorate (SKI), Stockholm, Sweden. ISSN 1104-1374, ISRN SKI-R-05/24-SE.
  • T. S. Nguyen and L. Jing (eds.), DECOVALEX III/BENCHPAR projects: implications of thermal-hydro-mechanical coupling on the near-field safety of a nuclear waste repository in a homogeneous rock mass, Report of BMT1B/WP2. February 2005. SKI Report 2005:25, Swedish Nuclear Power Inspectorate (SKI), Stockholm, Sweden. ISSN 1104-1374, ISRN SKI-R-05/25-SE.
  • L. Jing and T. S. Nguyen (eds.), DECOVALEX III/BENCHPAR projects: evaluation of the impact of thermal-hydro-mechanical couplings in bentonite and near-field rock barriers on a nuclear waste repository in a sparsely fractured hard rock, Report of BMT1C/WP2. February 2005. SKI Report 2005:26, Swedish Nuclear Power Inspectorate (SKI), Stockholm, Sweden. ISSN 1104-1374, ISRN SKI-R-05/26-SE.
  • J. Andersson, I. Staub and L. Knight, DECOVALEX III/BENCHPAR projects: approaches to upscaling thermal-hydro-mechanical processes in a fractured rock mass and its significance for large-scale reposirory performance assessment, Summary of findings, report of BMT2/WP3, February 2005. SKI Report 2005:27, Swedish Nuclear Power Inspectorate (SKI), Stockholm, Sweden. ISSN 1104-1374, ISRN SKI-R-05/27-SE.
  • T. Chan, R. Christiansson, G. S. Boulton, L. O. Ericsson, J. Hartikainen, M. R. Jensen, D. Mas Ivars, F. W. Stanchell, P. Vistrand and T. Wallroth, DECOVALEX III/BENCHPAR projects: the thermal-hydro-mechanical responses to a glacial cycle and their potential implications for deep geological disposal of nuclear waste in a fractured crystalline rock mass, report of BMT3/WP4. February 2005. SKI Report 2005:28, Swedish Nuclear Power Inspectorate (SKI), Stockholm, Sweden. ISSN 1104-1374, ISRN SKI-R-05/28-SE.
  • J. Andersson, J.A. Hudson, DECOVALEX III project: thermal-hydro-mechanical coupled processes in safety assessments, report of Task 4. February 2005. SKI Report 2005:29, Swedish Nuclear Power Inspectorate (SKI), Stockholm, Sweden. ISSN 1104-1374, ISRN SKI-R-05/29-SE.
  • An overall summary paper of the DECOVALEX III project was published on a special issue of the International Journal of Rock Mechanics and Mining Sciences, Volume 42, Number 5-6, 2005: C.-F. Tsang, L. Jing, O. Stephansson and F. Kautsky, The DECOVALEX III project: A summary of activities and lessons learned. Int. J. Rock Mech. Min. Sci., 2005, 42 (5–6): 593–610.

16 more papers were generated based on the achievements of this project and published on this special issue and they are listed at the end of each task description.