Two regions selected for Swiss repository studies

Friday, 30 January 2015

Two sites have been selected by Switzerland's national radioactive waste disposal cooperative Nagra for further investigation for hosting deep geological repositories.

Nagra has proposed that further investigations are carried out at the proposed siting regions of Zürich Nordost and Jura Ost in the third and final stage of Switzerland's plan for selecting sites for two repositories: one for low- and intermediate-level waste (LLW/ILW) and the other for high-level waste (HLW).

The sites under investigation (Image: Nagra)

Nagra is required by federal guidelines to making siting proposals that will provide the basis for the decision to be made by the Federal Council - expected in 2017 - on stage two of the process. Six sites were proposed in November 2011 during the first stage of the selection process. Nagra is required to propose at least two regions to host each of the repositories for further investigations in the third stage.

Having carried out a safety-based comparison for the siting regions in line with the requirements specified by the Federal Nuclear Safety Inspectorate (ENSI), Nagra has now selected Zürich Nordost and Jura Ost for further investigation.

The four other regions under consideration in the second stage - Südranden, Nördlich Lägern, Jura-Südfuss and Wellenberg - will be placed in reserve. Nagra said, "Geological siting regions can only be placed in reserve if they show clear disadvantages in terms of safety compared with the other regions, as evidenced by geological investigations carried out to date."

Nagra CEO Thomas Ernst said that while all six sites fulfil the strict safety requirements specified by ENSI, the Zürich Nordost and Jura Ost regions best fulfil the safety requirements for both a HLW and a LLW/ILW repository.

"The investigations have shown that the impermeable rock formations that provide safe containment of the waste occur at an optimum depth in these regions; they are protected against erosion, are stable on the long-term and are sufficiently large," Nagra said.

It added, "The most important criterion for decision-making in the context of site comparison is long-term safety. The siting regions were evaluated and compared in a stepwise process, taking into consideration only scientific and technical criteria; societal and political aspects are not relevant in this respect."

Nagra submitted its siting proposals to the Swiss Federal Office of Energy at the end of December 2014. The proposals are currently being reviewed by ENSI.

Up until 2006, much of Switzerland's used nuclear fuel was sent overseas for reprocessing. High level waste, and used fuel from 2006 onwards, is mostly stored at a central interim storage at Wurenlingen. Nagra has been operating an underground research laboratory for a high-level waste repository at Grimsel since 1983.

Researched and written
by World Nuclear News