On 9th September 2015, at a media conference hosted by the SFOE, ENSI explained that Nagra was required to submit further technical documentation. The requirement relates to the question of optimisation of the repository depth in terms of safety and is particularly relevant for deciding whether the Nördlich Lägern siting region should undergo further investigation in Stage 3 of the Sectoral Plan process. Nagra stands by its position that, while a repository can be constructed safely at a depth of 900 metres, such a depth has disadvantages compared to a depth of 700 metres.

Preparing the additional documentation called for by ENSI on the indicator «Depth with respect to engineering feasibility» will take around half a year. Nagra will submit the documents to the authorities and they will be published openly. The final evaluation by ENSI is expected for spring 2017.

To be prepared for every eventuality, Nagra has already begun planning the investigations for the Nördlich Lägern region (see media release of 16th December 2015). This will allow further delays to be avoided if ENSI’s review of the documentation leads them to conclude – contrary to Nagra’s position – that Nördlich Lägern should be investigated further. An exploration concept for Stage 3 will be prepared and planning initiated for a 3D seismic campaign and potential locations for deep boreholes.