Statement on the SFOE media conference of 9th September 2015 – the aim is to optimise safety

The call by ENSI for additional documentation is part of the scientific discussion surrounding the optimisation of the safety of deep geological repositories.

On 9th September, at a media conference hosted by the SFOE, ENSI explained that Nagra would be required to submit additional technical documentation on its siting proposals for Stage 3 of the Sectoral Plan process. The SFOE stated clearly that such calls for supplementary data are not unusual in the context of complex scientific-technical review processes of the type being conducted by ENSI.

Nagra’s position:
In January 2015, we announced our proposals for the geological siting regions to undergo further investigation in Stage 3 of the Sectoral Plan process. At that time, all the results of our investigations were presented fully and openly. Around 150 reports supporting the proposals (comprising more than 15,000 pages) were published on our website.

The expert discussions that will now take place are scientific deliberations on optimising the depth at which repositories should be constructed. The fact that experts evaluate underlying facts and assumptions differently, which then leads to more detailed discussions, is not unusual in such a process.

We are proceeding on the assumption that Nagra will receive detailed information from ENSI on the individual points of contention in the coming weeks and that discussions will then follow at a technical level. The results of these analyses will then allow us to continue with our work, for which we will take the time we need.

To make the situation clear: The call by ENSI for additional information applies to one specific indicator out of a total of 40. It relates to the question of optimising the depth of a repository from a safety perspective and is particularly relevant for deciding whether the Nördlich Lägern siting region should undergo further investigation in Stage 3. We are of the opinion that a repository can be constructed safely at a depth of 900 metres; however, compared to a depth of 700 metres, such a depth would have disadvantages in terms of safety.