Safe closure of deep geological repositories

The EU Commission Euratom has initiated a technology development project for testing plugging and sealing systems for geological disposal facilities for radioactive waste. Fourteen partners from eight European countries, including Nagra (National Cooperative for the Disposal of Radioactive Waste), are participating in the project.

Fourteen nuclear waste management organisations and research institutes from eight European countries are participating in the DOPAS project (Full-Scale Demonstration Of Plugs And Seals). The project is aimed at developing and testing plugging and sealing systems for geological repositories for radioactive waste and is built around a set of full-scale underground demonstrations, laboratory experiments and performance assessment studies. The project budget for the next four years is € 15.7 million (around 19 million Swiss Francs), with the EU Seventh Framework Programme contributing € 8.7 million. The project work is being carried out in several European countries and is organised and coordinated by the Finnish nuclear waste management company Posiva Oy.

As part of the DOPAS project, five full-scale plug and seal tests will be carried out for the rock types granite (in Finland, Sweden and the Czech Republic), clay (in France, with Swiss participation) and salt (in Germany). Combined with the results and experience from international research programmes, this will allow optimum plugging and sealing systems to be developed for all types of rock.

The sealing experiment for clay, in which Nagra is involved, will be carried out under the lead of the French nuclear waste management organisation Andra in a surface workshop located close to the Meuse / Haute Marne rock laboratory. Clays are the preferred host rocks for geological disposal in Switzerland and Nagra will be able to bring its wide experience from experiments in the Grimsel and Mont Terri rock laboratories into the project. “The project is of interest because it allows plugging and sealing systems to be tested under conditions similar to those in a future repository”, explains Tim Vietor, Head of the Field Investigations Section at Nagra. Benefiting from synergies, learning from one another and working together towards finding safe, long-term solutions – as exemplified by the DOPAS project – are the daily routine in the area of research on nuclear waste management.