Third Swiss region to be included in repository studies

The Nördlich Lägern region of Switzerland should be included in the third and final stage of the country's plan for selecting sites for two repositories, the Swiss Federal Nuclear Safety Inspectorate (ENSI) has proposed. Switzerland's national radioactive waste disposal cooperative Nagra earlier suggested the area be excluded.

The siting regions under investigation (Image: Nagra)

Six sites were proposed in November 2011 during the first stage of the selection process for the siting of two repositories: one for low- and intermediate-level waste (LLW/ILW) and the other for high-level waste (HLW). Nagra is required to propose at least two regions to host each of the repositories for further investigations in the third stage.

In January 2015, Nagra proposed that further investigations are carried out at the proposed siting regions of Zürich Nordost and Jura Ost in the third and final stage. It also said the four other regions under consideration in the second stage - Südranden, Nördlich Lägern, Jura-Südfuss and Wellenberg - will be placed in reserve.

In September 2015, ENSI requested that Nagra submit additional technical documentation related to the optimization of the repository depth in terms of safety. It was required to show whether construction at greater depth involves disadvantages in terms of safety and whether modifying the repository concept would be advantageous for such depths.

Nagra submitted the additional documentation to ENSI in August, claiming there are no safety advantages to constructing a deeper repository than originally envisaged. However, at that time it said it would carry out 3D seismic measurements in the Nördlich Lägern region from autumn 2016 and prepare applications in early 2017 for exploratory boreholes in the region to avoid further delays in the site selection process, should ENSI propose the region be included in further investigations.

ENSI was expected to complete a detailed review in early 2017 of the reports and analyses submitted by Nagra. Based on the result of these examinations, the Federal Council is expected to decide by the end of 2018 whether to agree with the location areas proposed by Nagra for consideration in the third stage.

However, ENSI said it has now completed its analyses and the Federal Office of Energy has decided to announce the assessment results ahead of schedule.

ENSI director Hans Wanner said, "We have come to the conclusion that the evaluation by Nagra is unsustainable. Our guidelines stipulate that a potentially suitable location should not be allowed to leave the procedure at an early stage due to an incomplete data base. For this reason, we recommend to investigate Nördlich Lägern further in the third stage."

Researched and written
by World Nuclear News