Thermo-Hydro-Mechanical (THM) coupled processes for performance and safety assessments of nuclear waste repository: Lessons learnt from EC BENCHPAR Project

Overall results and findings of BENCHPAR (acronym of BENCHmark Tests and Guidance on Coupled Processes for Performance Assessment of Nuclear Waste Repositories) project are presented. BENCHPAR project is aimed to improve the thermo-hydro-mechanical (THM) coupled processes content of radioactive waste repository Performance and Safety Assessments (PA/SA) with five Work Packages. The methodology for conducting a technical auditing for THM modelling was developed. The project has addressed the problem at the near-field, up-scaling and far-field scales through three benchmark test cases. In each benchmark, the importance of THM coupling is evaluated and presented. Finally the project provides a Guidance Document outlining how to include the THM processes in PA studies. (authors)