Konrad repository
BGR advises the BGE on geoscientific and geotechnical issues relating to the Konrad site. The legal basis for the advisory services is the “Agreement on Cooperation between the BGE and BGR” dated August 22nd, 2018. The BGE assigns geoscientific and geotechnical tasks to BGR, which BGR handles under its own technical and administrative responsibility.
Ore was mined from a deposit in the “Gifhorner Trog” at the Konrad iron ore mine in Lower Saxony from 1965 onwards. The ore deposits in this geological structure do not reach the earth's surface at any point and were discovered in 1933 during oil drilling. Due to the particularly favorable structural and hydrogeological conditions, investigations into the suitability of the Konrad site as a final repository for low and intermediate radioactive waste began after ore mining stopped in 1976.
The results of the investigations confirmed the favourable overall geological conditions for the establishment of a final repository for low heat-generating waste. The favourable overall conditions are determined by the great depth of the planned storage fields in the iron ore (approximately 1,000 meters) and by the overburden of the host rock with very low-permeability claystones several hundred meters thick. Model calculations have shown that, in the long term, no radionuclides can escape from the storage level into the biosphere and that the maximum radiological exposure will be about 100 times smaller than the range of natural radioactivity.
The plan to construct a final repository for radioactive waste with negligible heat generation in the Konrad mine was submitted on August 31st, 1982, and approved by the Lower Saxony Ministry of the Environment on May 22nd, 2002. Appeals against this approval were rejected by the Lower Saxony Higher Administrative Court (Niedersächsisches Oberverwaltungsgericht) in Lüneburg on March 8th, 2006, without leave to appeal. Some plaintiffs filed an appeal against this ruling with the Federal Administrative Court (Bundesverwaltungsgericht). The appeal was rejected by the Federal Administrative Court (Bundesverwaltungsgericht) in March 2007. This meant that the plan approval decision became final and enforceable 25 years after the application was filed. In May 2007, above-ground and underground conversion work began on the former mine to create Germany's first final repository approved under nuclear law. Subsequently, up to 303,000 cubic meters of low- and medium-level radioactive (and therefore negligible heat-generating) waste may be stored there.
As part of the restructuring of the final repository sector initiated by the legislature in 2016, the Federal Company for Final Repository (BGE) took over responsibility for operating the Konrad final repository from the Federal Office for Radiation Protection (BfS) in 2017. According to the BGE's schedule, the final repository is to be completed in 2027.
The expansion of the Konrad mine into a final repository is being carried out on the basis of the plan approval decision, which is based on the state of the art in science and technology at the time. The BGE is continuing the voluntary procedure initiated by the BfS in 2016 to “review compliance with the safety requirements of the Konrad final repository in accordance with the state of the art in science and technology” (USiKo). This involves several phases to check whether there are any safety-relevant deviations between the state of science and technology at the time and today. The first phase, which was completed in 2021 with a report, revealed deviations, some of which are also considered relevant for the safety analysis of the Konrad repository. However, the experts note in their final report: “In the opinion of the review team, phase 1 did not reveal any aspects that would fundamentally call into question the safety assessment.” Based on the deviations identified, in-depth investigations of the safety analyses has been carried out in phase 2 of the USiKo and will be updated as necessary. The findings of these investigations have been presented to the public in autumn 2024.
BGR is currently working on selected issues relating to stress and deformation conditions and hydraulic conditions. These investigations are primarily being carried out with a view to ensuring the stability of the mine workings and the integrity of the surrounding rock, but also to characterize the geological, geomechanical, and hydraulic properties of the rock and the geological barrier. This work includes the evaluation of geotechnical and mine surveying measurements as well as extensive studies. In the recent past, the scientific status of the long-term deformation behavior of claystone was comprehensively presented in a BGR report (see below) with a view to the claystones exposed in the Konrad repository. On the other hand, investigations and measurements are also being carried out on site at the Konrad mine. These include measurements of the stress state in the rock using the BGR overdrilling method as a basis for designing the support in large areas of the infrastructure zone, as well as measurements to determine the permeability of the rock in the near and far field of mine workings and optical borehole recordings for stratigraphic determination.