25 Years of BGE TECHNOLOGY GmbH

July 13, 2000 marks the official founding date of BGE TECHNOLOGY GmbH (BGE TEC – then still DBE TECHNOLOGY GmbH (DBE TEC)) under the managing directors Hartmut Meyer and Dr Jürgen Lempert, who was succeeded after one year by Michael Ripkens.

DBE TEC has been involved in all aspects of radioactive waste from an early stage and has, for example, supported licensing procedures for interim storage facilities at nuclear power plant sites. DBE TEC also provided construction supervision services for the interim storage facilities. DBE TEC has supported international waste management programmes, for example in Belgium, France, Japan, Romania, and the Czech Republic. For site characterisation, too, DBE TEC was in demand internationally and carried out projects in Argentina and Kazakhstan.

Early on, DBE TEC supported work on sealing dam structures in saliniferous formations, based on a systematic research and analysis of historical dam structures. Grouting of the excavation-damaged zone with sodium silicate was later qualified for use in the Asse mine. In underground preliminary tests, the penetration behaviour was investigated and both the suitability and processability were evaluated. As part of the quality assurance of the Sorel concrete used for the construction of flow barriers, a method suitable for construction sites was implemented to investigate the temperature development, which allows conclusions to be drawn about the setting behaviour and processing times.

The building material salt concrete played a central role for the Morsleben repository (ERAM), as it was used as supporting backfill for cavities, in the planning of drift seals, and in a large-scale test. During the backfilling of parts of the mine between 2003 and 2011, DBE TEC supported its parent company DBE with the recipe adjustments, the building material analyses, and ultimately with the use of the building material as part of the mining hazard prevention measure, where approx. 1 million m³ of material were placed in the central section of the ERAM.

As an alternative to the then existing backfill materials, DBE TEC, in collaboration with GRS gGmbH, developed a self-healing backfill material as part of the AISKRISTALL R&D project from 2002 to 2004 – a material that meets the requirements for processability, impermeability and strength, as well as the availability of its components.

A large proportion of the tasks dealt with in the early years involved planning work and numerical verifications for backfilling and sealing measures in mines. The above-mentioned backfilling measures in the ERAM were implemented not least because – based on numerical calculations – employees of DBE TEC correctly predicted that rock would break from the roof of its central part.

In order to be able to mathematically describe the thermo-mechanical effects of the backfilling measures on the mine, a constitutive model was developed and adapted. This was used in large-scale numerical models to analyse the effects of the backfilling measures on the stability of the mine workings. During the mining hazard prevention measures, this was done using the observation method by comparing numerical forecast calculations with daily measurement data.

In addition to AISKRISTALL, ASTER, GEIST and GENESIS were among the first R&D projects carried out by DBE TEC on behalf of the Federal Government via the Project Management Agency Karlsruhe, which established a very good relationship with the latter. These initial projects already show the breadth of the work spectrum and also laid the foundations for successful collaborations. ASTER refers to site investigation requirements for HLW repositories in hard rock. As part of a German-Russian scientific and technical cooperation, this project not only intensified the cooperation with the Russian colleagues, but also the cooperation with GRS and BGR. This cooperation between GRS, BGR, and DBE TEC was to develop into many very successful joint R&D projects.

With GEIST and GENESIS, DBE TEC focused on another potential host rock for a future HLW repository: claystone. While GEIST initially focused on comparing repository concepts in salt and claystone, GENESIS already carried out initial investigations into the safety design of such a repository in claystone. Even though the details of the repository concepts changed over time, DBE TEC was already concentrating on technical feasibility studies and numerical calculations at generic sites in northern and southern Germany at that time.

DBE TEC had the opportunity to participate in heater experiments and mine-by tests at the Mt Terri and Bure URLs and to accompany these with THM-coupled calculations. The tests were also used to test fibre-optic measuring systems, which were co-developed by DBE TEC. The knowledge gained on the mechanical behaviour of claystones could later be used for targeted measures at the KONRAD mine.

The following photo scroll bar presents selected snapshots highlighting key milestones and memorable moments from this period.

During the period covered by this newsletter, DBE TECHNOLOGY GmbH (DBE TEC) established itself as a strong organisation within the waste management community, making many valuable contributions to waste management programmes in Germany and abroad. Under DBE TEC’s leadership, a consortium with varying composition of WMOs from France, Belgium, the Netherlands, Spain, and the UK supported the EU in establishing WMO programmes in Eastern Europe. At the same time, DBE TEC began carrying out its first projects for the design of near-surface repositories.

From 2005 to 2010, the integrated EC project ESDRED (Engineering Studies and Demonstration of Repository Designs) and the associated German project DENKMAL were key initiatives for DBE TEC. The primary objective of EU Project ESDRED was to demonstrate the technical feasibility of specific techniques for HLW repositories on an industrial scale, including the construction, operation, backfilling, and closure of facilities. DBE TEC developed, constructed, and tested transport and emplacement equipment for a vertical borehole disposal concept. Tailored to the specific boundary conditions of a repository in a domal salt formation, a so-called emplacement device enabled disposal in up to 300-metre-deep boreholes. While the DBE department from which DBE TEC had spun off had already gained experience in carrying out similar large-scale tests in the 1990s, this was the first project of its kind for DBE TEC. The project’s scientific and technical impact was recognised far beyond the company’s borders. The successful demonstration experiments and reliability tests advanced the state of the art and the technical basis for radioactive waste disposal. Further concepts based on this technology were developed in subsequent projects.

A notable milestone in this period was the VSG (‘Vorläufige Sicherheitsanalyse Gorleben’) project (2010–2013). The project team, consisting of BGR, DBE TEC, GRS, IfG, iSTec, KIT, and various institutes from the universities of Frankfurt, Aachen, and Clausthal, conducted a thorough preliminary safety analysis of a potential HLW/SNF repository in domal rock salt formations. This analysis was based on existing data from the Gorleben site. Although the Gorleben salt dome is no longer considered a potential repository site, the VSG’s work set a standard for future safety analyses in Germany. The VSG was primarily based on the ISIBEL I and II R&D projects, which provided the tools for safety assessment. As part of the VSG project, a safety assessment concept was developed based on site data, information on the quantities and types of waste, and repository planning and design. A FEP catalogue was created and scenarios were developed in the course of a system analysis, which were then considered in a performance assessment, including numerical integrity analyses of the geologic and geotechnical barriers.

The REPOPERM I and II R&D projects provided valuable insights that also supported the VSG. These projects demonstrated through mathematical modelling that combining short-term seals made from conventional building materials with long-term seals of moist crushed salt could achieve functionality within a few hundred years, enabling a safe containment concept without radionuclide release.

During this period, BGE’s predecessor organisations BfS and DBE advanced with planning for the decommissioning of the Morsleben repository site (ERAM). As part of the safety concept, an in-situ test of a drift sealing structure in rock salt at a scale of 1:1 was conducted. The test dam, made of salt concrete, was constructed in 2010. DBE TEC supported its parent company in developing construction materials and ensuring quality during construction, as well as in providing numerical forecasts, back-analysis calculations, and an evaluation of accumulated measurement data. Although some local cracks were observed, which were unexpected, it was demonstrated that the 25-metre-long dam is sealed with a permeability of less than 1E-19 m². Even if the material used to build such structures has changed since then, the test provided valuable findings.

Another focus of DBE TEC’s work was on reducing the hydraulic permeability of the excavation-damaged zone (EDZ), for example at drift or shaft seal sites. As part of the VERA R&D project, injection methods and sodium silicate-based injection materials were developed for this purpose. In addition to studies on injection processes, the permeability achieved was tested. This technology has been patented and has since been used for many sealing projects in the Asse mine.

Developments in the German disposal programme have always been reflected in DBE TECHNOLOGY GmbH’s (DBE TEC) areas of focus. For example, requirements were introduced in 2010 by the Federal Ministry for the Environment for the first time in the German programme that the retrievability of waste is a fixed design requirement. Hence, the impact of retrievability on repository concepts was investigated in various R&D projects from 2012 onwards. ASTERIX, DBE TEC’s first project in the series, aimed at investigating the effects of retrievability on existing disposal concepts and at identifying requirements for new concepts. Building on this, ERNESTA developed technical concepts for the retrieval of waste containers with heat-generating radioactive waste from disposal facilities in salt and claystone formations. Part of this development also involved questions about the ambient temperatures encountered during such retrieval operations and the determination of corresponding technical limits. In recent years, this work has been re-introduced into the discussion on the definition of threshold temperatures in the German site selection process. The R&D series on ‘retrievability’ was completed in 2019 by the KOREKT project with a focus on crystalline host rock.

Due to the political decision to restart the search for a site for a repository for heat-generating radioactive waste, salt, clay, and crystalline rock are to be investigated regarding their potential to host a repository. This realignment led to various R&D projects carried out between 2013 and 2018 on behalf of the Federal Ministry for Economic Affairs and Energy.

Starting from a preliminary safety analysis for a future HLW/SNF repository site in a domal rock salt formation (VSG project), the KOSINA project team of BGR, GRS, IfG and DBE TEC developed concepts for flat-bedded salt and salt pillows. For both types, safety and safety demonstration concepts as well as repository design and emplacement concepts were prepared, including geomechanical integrity analyses and studies on operational safety.

Within the scope of the ANSICHT project, jointly carried out by BGR, GRS, and DBE TEC, a methodology to demonstrate the safety of a HLW repository in claystone in Germany was prepared and tested at two generic sites. This included the development of a repository concept together with emplacement and sealing concepts. A FEP catalogue and a scenario development were derived. One particular challenge was the specification of general integrity criteria for the geological barrier in such a way that their compliance can be verified by means of numerical calculations – and of course, the corresponding computational demonstration of the barrier integrity itself.

As another potential host rock for heat-generating waste in Germany, crystalline rock was increasingly investigated. The first question to be answered was whether and to what extent the concept of containment-providing rock zones (CRZ) can be applied to this type of rock and how the integrity requirement must be defined. This was answered positively within the framework of the R&D project CHRISTA.

Furthermore, colleagues at DBE TEC supported ONDRAF/NIRAS, the Belgian waste management organisation, in conducting a feasibility study on the future operation of a repository for high-level and/or long-lived radioactive waste in weakly consolidated clays. In addition to studies on shaft conveyor systems, waste emplacement technology, and repository ventilation, a key task was to develop a suitable backfill material for the emplacement drifts. It was important to ensure that the strength of the backfill material was low enough to allow the retrieval of the disposal containers. The backfill material was to be produced using above-ground equipment and pumped through the shaft and access tunnels into the emplacement drifts. The flow behaviour of the backfill material was investigated using a mock-up test. The measurement data recorded during the test were used to design mixing, pumping, and conveying equipment. A high-performance building material conveyor system was developed that enables the transport of the backfill material in the required quality and quantity, taking into account aspects of plant operation and occupational safety. The findings from national repository projects were applied, further developed and adapted to the specific requirements of the Belgian repository during these tasks.

During the period presented here, DBE TEC also refined its expertise in designing and planning types of repositories that are not included in the German programme. Particularly noteworthy in this context are near-surface repositories for LILW and, later, borehole disposal. These projects, which were and are spread across the globe, have made DBE TEC an important source of information for international programmes.

In late 2017, DBE and related bodies merged into Bundesgesellschaft für Endlagerung (BGE), unifying radioactive waste disposal under one federal company. DBE TECHNOLOGY GmbH was renamed BGE TECHNOLOGY GmbH and remains BGE’s wholly owned subsidiary.

The following photo scroll bar presents selected snapshots highlighting key milestones and developments from this period.