EURAD - D17.3 Lessons from URL Experiments
Waste management organisations (WMOs) will collect significant quantities of data during repository monitoring programmes. These data are likely to be used for the purposes of aiding decision making and building further confidence, particularly in the safety case. Confidence must exist in the collected monitoring data to successfully fulfil the aims of repository monitoring programmes. Confidence will be built by demonstrating that:
• Appropriate repository monitoring system designs are implemented.
• Effective methods are used to acquire, manage and use monitoring data.
Work Package (WP) 17 of the EURAD programme - Monitoring Equipment and Data Treatment for Safe Repository Operation and Staged Closure (MODATS), addresses monitoring data acquisition, management and analysis development needs through research activities in Task 2 (Data Treatment for Increased Confidence in Repository Monitoring).
The most relevant monitoring system design and data acquisition, management and analysis knowledge and experience to date has been gained from monitoring activities in underground research laboratory (URL) experiments because, in the main, repositories are not yet operating.
A survey of URL experiments has been undertaken to learn lessons for monitoring in repositories during construction, operation and closure to support the research and development activities in Task 2. Seventeen experiments have been surveyed. Some of these experiments are completed and have been dismantled, while others are ongoing. They are conducted in different engineered barrier system (EBS) components and in different host rocks. Some of the experiments aim to understand the behaviour and test the performance of individual EBS components, while others aim to develop further understanding of one or more thermal, hydraulic, mechanical, chemical, gas and radionuclide transport (THMCGR) processes in one component of the multi-barrier system or in full-scale repository concepts. Some of the experiments also test materials and emplacement technologies.
The MODATS WP is using five Reference Experiments to underpin the research and development activities in Task 2, for example, by providing results to support the development of data management approaches. The MODATS Reference Experiments are:
• The ALC1605 experiment (Bure URL, in France).
• The Full-Scale Emplacement (FE) experiment (Mont Terri URL, Switzerland).
• The Posiva Plug (POPLU) experiment (ONKALO, Finland).
• The Preliminary demonstration test for CLAY disposal of highly radioactive waste (PRACLAY) experiment (HADES URL, Belgium).
• The Prototype Repository II experiment (Äspö Hard Rock Laboratory, Sweden).
The Reference Experiments are included in the survey.
This report summarises the survey responses to develop lessons for repository monitoring relating to the design of monitoring systems and the acquisition, management and use of monitoring data. The lessons are discussed in detail in Section 3 of this report. It should be noted that the lessons are exclusively learned from the survey. However, further understanding of these aspects of monitoring is available elsewhere.
The lessons for repository monitoring are presented below, along with some related gaps in understanding.