The Gorleben mine
The Gorleben salt dome is located in the municipality of Gorleben in the Lüchow-Dannenberg district of north-east Lower Saxony. East of the River Elbe, the dome continues as the Gorleben-Rambow salt dome. On the Lower Saxony side, it is around 14 kilometres long and up to 4 kilometres wide. Aged around 250 million years, the salt extends from a depth of 250 metres to a maximum of 3,400 metres below the ground surface.
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Explorations
In 1977, the state of Lower Saxony selected the Gorleben site as a “provisional site” for a “possible nuclear waste management centre” with a reprocessing plant, fuel element plant and repository. Due to considerable public protests, the plan for a nuclear waste management centre was abandoned again in May 1979. However, the Gorleben salt dome was still seen as a potential site for a repository.
From autumn 1979 onwards, the salt dome was explored with a view to its possible use as a repository. Construction of the Gorleben exploratory mine began in the 1980s. Extensive surface and underground exploration was carried out – but radioactive waste was not brought underground into the salt dome at any point. Working groups were formed in addition to further technical and accompanying political bodies, and numerous technical reports were produced on the suitability or unsuitability of the Gorleben salt dome as well as on safety aspects during the construction of a repository. Many repository-specific investigation methods that were developed during the exploratory campaign in Gorleben represent a good starting point for the current site selection procedure.
Contact
Bundesgesellschaft für Endlagerung mbH
Eschenstraße 55
31224 Peine
Press: 05171 43-1804
Email: dialog(at)bge.de
Scrutiny by the general public
Since 1977, repository research has been scrutinised primarily by the general public and in particular by the Lüchow-Dannenberg Citizens’ Initiative. The latter has also commissioned and published technical reports on the suitability of the Gorleben salt dome as a repository site. For example, the Initiative – or rather the association Rechtshilfe Gorleben e. V. – commissioned a study on the “Evaluation of the Gorleben repository site” in 2011. This study referred primarily to content from the Gorleben preliminary safety analysis (VSG) and evaluated the Gorleben-Rambow salt dome in terms of its suitability/unsuitability as a repository for high-level radioactive waste.
End of Exploration
Part of the former surrounding wall. All but a few sections of wall have now been removed.
With the adoption of the Repository Site Selection Act (StandAG) in 2013, exploratory work in Gorleben was discontinued. The Gorleben site was treated like any other potential site in Germany within the framework of the site selection procedure. On 29 July 2014, the Federal government and the state of Lower Saxony agreed that not only the mine cavities that had been kept in operation but also the surface installations would be scaled back to the size needed to keep the mine open. In addition, the safety installations would be reduced to the level of a normal industrial facility. Underground, the areas that are no longer needed in order to keep the mine open have been decommissioned and sealed off. Machinery and vehicles that are no longer needed have been brought above ground and withdrawn from service.
Above ground, the size of the mine site has been reduced considerably, and changes have been made to the mine infrastructure. Buildings and installations that are not needed purely to keep the mine open have been dismantled. The building housing both the changing facilities and the administration and archive of the Gorleben mine continues to be used as part of the closure work. In 2019, all but a few sections of the surrounding wall that had long protected the site against unauthorised access were removed, and the downsized facility was surrounded with standard industrial fencing. One section of the wall was retained in response to calls from the region. It will be for local politicians in the Lüchow-Dannenberg district to advise on whether and how it can be preserved in the long term.
The end for Gorleben
The Gorleben salt dome has been eliminated from the site selection procedure and will not therefore be considered as part of subsequent work by the BGE on proposals for siting regions. This is because, following the application of the geoscientific weighing criteria, it did not become a sub-area in accordance with section 24 of the Repository Site Selection Act. After an initial examination of the geological data, it was clear that the salt dome could not meet the requirement of being the site with the best possible safety for a million years. The salt dome was rated as unfavourable on all three indicators for the geoscientific weighing criterion from Annex 11 to the Repository Site Selection Act, which is known as the overburden criterion. The dome’s elimination from the site selection procedure was announced publicly in late September 2020 at the presentation of the Sub-areas Interim Report. Full details of the elimination of the Gorleben salt dome from the site selection procedure can be found in the multimedia application at the bottom of the page.
For several decades, the plan was to turn the mine into a repository for high-level radioactive waste. With this in mind, some €1.9 billion had been invested in the mine and exploratory work by 2021. The salt dome in Gorleben has undergone several decades of exploratory work interspersed with interruptions of several years. These exploratory activities were intended to evaluate its suitability for use as a repository for high-level radioactive waste. The final results are not yet available.
Closure
In September 2021, the Federal Environment Ministry decided that Gorleben was to be decommissioned – and tasked the BGE with the mine’s closure. The first step in that process was completed in August 2023, when the BGE awarded the contract to backfill the mine. At present, this first phase – the backfilling of the mine cavities – is projected to take three years.
The mine is to be backfilled using salt that was extracted from the subsurface for exploration purposes. In the 1980s, when construction work began on the shafts for an exploratory mine in the salt dome, salt was transported to the surface. Since then, approximately 400,000 tonnes of rock salt have been stored in a salt heap in the immediate vicinity – and this material will now be used to backfill the mine.
Phases of closure
The project to close the Gorleben mine consists of multiple phases. In Phase 1a, the salt heap will be reused and the mine cavities backfilled. This will involve bringing the surface salt heap underground and backfilling the cavities of the mine with the material.
According to the mass balance, part of the salt heap is expected to be left over after backfilling is completed. The remaining material would then be removed in Phase 1b.
Phase 2 describes the backfilling, dismantling and sealing of the shafts. Potential materials for backfilling are currently being examined. During the excavation of the mine and the exploration of the salt dome, the shafts that lead vertically downwards were used to transport people, machinery and material underground and to the surface.
Phase 3 includes plans for the dismantling of the surface installations, rehabilitation of the site, and the site’s ultimate release from mining authority control. Current plans assume that closure will be completed in the early 2030s. What will happen with the site once the closure work is completed remains unclear. Planning the site’s subsequent use is not part of the BGE’s remit.
Construction work in the immediate vicinity of the building Gatehouse 1.
The Gorleben salt heap is being removed for the backfilling of the Gorleben mine, and the salt is being brought back underground.
An excavator weighing around 60 tonnes is used for the demolition of the loading system.
Brief summary
- For decades, the Gorleben salt dome has been explored with regard to its suitability as a location for a repository for high-level radioactive waste
- At no point was radioactive waste brought underground into the salt dome
- With the new Repository Site Selection Act (StandAG), exploratory work was discontinued in 2013 and operations shifted to those needed to keep the mine open
- The Gorleben salt dome was excluded from the site selection procedure in 2020 with the publication of the sub-areas interim report
- In 2021, the BGE was mandated to close the mine by the Federal Environment Ministry
- The salt heap is to be used for backfilling, and the contract for this work has already been awarded