Gorleben salt dome was explored in Germany from 1979 to 2012 as a site for the final disposal of radioactive waste. The aim of the exploration was to identify large homogeneous sections of rock salt in the salt dome into which the waste can be stored, as well as proof of barrier effectiveness for long-term safe containment of the waste.
BGR carried out and evaluated the geoscientific investigations at the exploration site. The investigations were carried out on behalf of the Federal Office for Radiation Protection (BfS) and in cooperation with the DBE (German Company for Construction and Operation of Waste Repositories, Peine).
As a result of the surface exploration, initial findings about the salt dome itself, the necessary knowledge about the overlying layers and the adjoining rock of the salt dome as well as the assessment of the groundwater conditions in the adjoining layers were available. On the basis of this knowledge, underground exploration of the salt dome began in 1986. For this purpose, two shafts were drilled in the central area of the main saddle of the salt dome at a distance of around 400 m and connected to each other via a connecting section at a depth of 840 m.
The underground exploration of the Gorleben salt dome was suspended in October 2000 on the basis of the agreement between the German Federal Government and the energy supply companies dated June 14, 2000. This moratorium ended after 10 years in October 2010. With the resumption of exploration work, the geoscientific investigations were also continued. Parallel to the further exploration, the results obtained to date were evaluated as part of the Preliminary Safety Assessment for the Gorleben Site (VSG). In December 2012, the exploration was terminated according to the “Act on the Search for and Selection of a Site for a Final Repository for High-Level Radioactive Waste” (Site Selection Act). In accordance with Section 36 of the StandAG, the Gorleben salt dome was included in the site selection process like any other potential site in accordance with the criteria and requirements set out in Sections 22 to 26.
On September 28, 2020, the Federal Company for Radioactive Waste Disposal (BGE), as the project owner in the site selection process, published the sub-area report. In accordance with Section 13 of the Site Selection Act, this report identifies those areas that are expected to have favourable geological conditions for the safe final disposal of radioactive waste. The Gorleben salt dome is not included in the sub-areas identified in this report. On September 17, 2021, the Federal Ministry for the Environment and Consumer Protection (BMU) decided to commission the BGEwith the decommissioning of the Gorleben mine. At the end of November 2024, the BGE began filling the Gorleben mine.
The geoscientific exploration work carried out by BGR included geological, mineralogical-geochemical, geophysical, and geotechnical in-situ investigations. This was supplemented by experiments on salt rock samples in the laboratory and accompanying model calculations for the interpretation of in-situ measurements and on-site observations.
The exploration results obtained by BGR were comprehensively documented in special technical reports for the Federal Office for Radiation Protection (BfS). The number of documents on the Gorleben site available in the archives of BGR amounts to almost 800 titles. BGR has summarized the results of the site investigation in four overview volumes on the geology of the overburden, hydrogeology, geology of the salt dome, and geotechnical investigations. These have been published as Geological Yearbooks C 71 to C 74 by Schweizerbart-Verlag. Their English translation, “Description of the Gorleben site,” has been published by BGR and is available for download. In addition, documentation of the structural exploration of the salt dome using georadar in tunnels and boreholes is available.