The Challenge of the Asse II Mine: Retrieval as a Generational Project

The retrieval of approximately 126,000 drums, decided upon over 15 years ago, is one of Germany’s most challenging environmental and safety projects. The storage chambers are located hundreds of meters below the earth’s surface in an environment that has aged over decades and is damp and corrosive. Storage conditions vary: some drums are covered in salt, while others are freely accessible. Some of the drums were neatly stacked at the time, while others lie in disarray. Safe retrieval requires machinery that is robust, precise, and remotely controllable – machines that do not yet exist for the environmental conditions prevailing in the salt mine.

Specialized machinery for extreme conditions

Bilfinger is developing a specialized recovery system for this purpose, the core of which is a highly automated, multifunctional test excavator. This is being built as a test system for the complex handling processes and is equipped with special tools such as specialized grippers, cutters, and buckets. As a long-standing partner to the nuclear industry and thanks to its deep engineering expertise, Bilfinger is able to develop custom-built machines that operate reliably even under extreme conditions.

Robotics, sensors, and assistance

For control and automation, Bilfinger relies on the long-standing expertise of the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation IOSB. Among other things, the institute contributes its experience from the “Robots for Decontamination in Hazardous Environments (ROBDEKON)” competence center, where it researches and develops teleoperated and autonomous construction machinery. This includes sensor fusion, 3D environmental perception, and machine automation. Inverse kinematics enables operators to position the tool directly and intuitively – the machine coordinates the path to that position autonomously. Repetitive work steps, such as placing grasped barrels into a transport box, are intended to be automated in the future.

Safe remote operation

The combination of these technologies creates a system that puts the control center at the heart of operations: Machine operators should be able to carry out the rescue from a safe distance, based on precise spatial orientation that goes far beyond simple camera images and is supported by advanced assistance functions. A digital twin of the recovery system virtually replicates the real-world environment, enabling operational states, movements, and load scenarios to be analyzed and optimized even before deployment. In a complex test environment, Bilfinger additionally simulates the conditions in the salt mine so that the interaction between mechanics, sensors, and software can be optimally coordinated.

Forward-looking comprehensive concept

By commissioning Bilfinger and Fraunhofer IOSB, BGE is relying on strong industry and research partners who are working in close collaboration to advance forward-looking technologies, maximize personnel safety, and support the on-schedule implementation of this generational task.

The ongoing development of the recovery system demonstrates that, through the synergy of robotics research, specialized mechanical engineering, and responsible project management, even challenges that exceed the current state of the art can be overcome. At the same time, expertise is being developed that can also be of great significance in other application areas – such as decontamination or maintenance work in hard-to-reach or hazardous areas.

Press contact:

Bilfinger Nuclear & Energy Transition GmbH:
Michaela Müller, Engineering & Sales Assistant, 0931/903-6003,
michaela.mueller@bilfinger.com

Fraunhofer IOSB:
Ulrich Pontes, Head of Press and Communications, 0721/6091-301,
presse@iosb.fraunhofer.de