In the next decades, many countries around the world will need to decommission their nuclear facilities as they have reached, or they will reach the end of their lifecycle. Nuclear decommissioning is very challenging because it was not foreseen during the planning and construction of the existing facilities, so many challenges and uncertainties are to be handled during decommissioning activities. Therefore, NDPs (Nuclear Decommissioning Projects) are relatively new, there are not fully standardized methods for carrying them out, and they are performed on a case-by-case basis depending on the country. At the international level, a common understanding of NDPs is being sought and the EU (European Union) has been funding programmes for research projects in this area.

Between October 2020 and November 2023, the project PLEIADES (PLatform based on Emerging and Interoperable Applications for enhanced Decommissioning processES) [1] was funded by the EC (European Commission) through the EURATOM (European Atomic Energy Community) programme. This project resulted in a platform connecting different digital tools together to improve the efficiency of the planning activities. Further research development needs were considered at the end of the project, mainly regarding extending the integrated technological tools, the ontology and data transfer. 

Launched in September 2024, the project DORADO (Digital twins and Ontology for Robot Assisted Decommissioning Operations) [2] is being carried out by a consortium that includes 7 of the former PLEIADES participants among others. Also funded by EURATOM, the main objective of DORADO is to improve safety and efficiency in NDPs using digital technologies such as AI (Artificial Intelligence), BIM (Building Information Modelling), robotics, voice recognition, or sensor data visualization. During DORADO, a digital twin (DT) using ontology-based data transfer protocol will be created. This DT will integrate digital tools into a coherent suite for broad variety of decommissioning applications. The following digital technologies may be analysed and implemented within the platform: sensor data fusion with temporal dimension; environment data comparison against BIM; point-cloud and 3D model change detection; dynamic modelling of digital twins for ALARA (As Low As Reasonably Achievable) dose estimation and planning; server-based integration with IFC (Industry Foundation Classes) file format and extended data queries; mission planning and robot route optimization; human-to-system smart voice assistant interface; and standardization using the common ontology.

Once completed, the platform aims to be used for tasks like: cost estimation; on-site waste characterization and sampling; remote segregation and packaging planning; risk identification and knowledge management; robotics and remote handling systems; or surface and structure cleaning, among others.

Sources

[1] PLEIADES Project website: https://pleiades-platform.eu

[2] DORADO Project website: https://dorado-project.eu

How to cite: Räty, A., Ridao Cabrerizo, J. A., Daniska, D., Gentes, S., and Rentschler, E.: Digital Twins and Ontology for Robot Assisted Decommissioning Operations: DORADO project, Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-120, https://doi.org/10.5194/safend2025-120, 2025.

Various cutting methods are available for dismantling the reactor pressure vessel and its internals. One process that offers many technical advantages is the water-abrasive suspension cutting process. In this cold cutting process, a high-pressure water jet mixed with abrasive particles is used for cutting. This way, even complex structures (e.g. fixtures) and components can be cut safely, remotely and quickly under mechanical tension. During cutting, a mixture of used abrasive and radioactive steel particles is produced, which must be disposed of as radioactive waste. This additional secondary waste to be disposed of increases with every cut and, in turn, increases the overall cost of the process. It makes the cutting technique unattractive despite its many technical advantages.

In order to reduce the amount of secondary waste, a separation process for the treatment of steel/abrasive particle mixture was developed. The process employed sieving and magnetic filtration to separate abrasive particles from the particle mixture. Firstly, the homogenous mixture of steel and abrasive particles is sieved, which removes the fine particles containing broken abrasive and small steel particles. In the next step, the sieved fraction is treated through a magnetic filter, removing bigger steel particles. The separation process aimed to reduce secondary waste by reusing abrasive particles for further WAS cutting.

In this regard, a prototype separation system with a sieve and magnetic filter was built and tested in a batch process. The shortcomings of the procedure related to the handling of material and upscalling the process so that it can be introduced to the market, suggested to develop a continuously operated separation plant that can be employed in nuclear facilities. To cope with these limitations, a continuously operated sieving mechanism and a magnetic filter were developed. The preliminary results of the continuously operated sieve have shown impressive results in terms of sieving error, but there is still room for improvement in terms of steady operation. Similarly, the innovative and patented magnetic filter exhibited quite exciting early results, but the process still requires a lot of improvement in terms of process control and measuring methodology.

In the ongoing research project, the continuous sieve and the magnetic filter will be validated under variable conditions and parameters. The improvements to the filter will be developed through simulations and experimental validation using 3D prints of new filter geometries, which can make the filter viable for other separation applications. The aim is to design and build a system with both components that can be used for abrasive treatment in nuclear facilities. Furthermore, the separation plant will be designed for use in nuclear facilities. In this regard, the project is supported in an advisory capacity by Iqony gmbh. They will provide expertise related to the special requirements for the nuclear sector right from the start of development. In the presentation, the preliminary results of the continuous sieve and magnetic filter will be presented.

How to cite: Chaudhry, M. J. E., Krauß, C.-O., and Heneka, A.: Validation of an innovative separation plant consisting of a sieve and magnetic filter for the reduction of radioactive waste for interim storage, Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-11, https://doi.org/10.5194/safend2025-11, 2025.

Germany's interim storage facilities are designed to last 50 years and are licensed to operate for 40 years. They will be needed much longer, as a final repository will not be available until 2050 at the earliest.

The objective of research project ZuMoBau-ZL is to develop a suitable condition assessment and monitoring concept for the structures for the interim storage facilities, including life prediction models, with which the remaining service life can be predicted, verified, and monitored as realistically as possible.

This effort will be carried out in four steps:

1) Compilation of a catalogue of damage and degradation mechanisms for nuclear interim storage facilities in Germany, considering the specific use, construction details and other boundary conditions. Weighting of relevant damage and degradation mechanisms and selection of suitable models for their description are the second part of this step.

2) Provision of an application matrix for non-destructive and low-destructive inspection methods, structural health and monitoring techniques, adapted to the catalogue of step 1, and identification of gaps in existing technologies.

3) Adapting and optimizing durability and performance models for the specific types of structures to allow predictions of future conditions and degradation, in order to optimize maintenance and repairing measures.

4) Provide interfaces to databases and BIM (Building Information Modelling). Selected methods and results will be demonstrated on a reference structure (CONCERTO) available at the Technische Universität Braunschweig.

The first two steps have been completed and will be updated after the demonstrations. The main degradation mechanisms identified as relevant are rebar corrosion and carbonation. Methods such as radar, ultrasound and air permeability measurements will be used to assess the condition. The reference structure will be equipped with various corrosion and moisture sensors and an innovative ultrasonic monitoring method in May 2025. The first data evaluation is expected in autumn 2025.

How to cite: Sperbeck, S., Niederleithinger, E., Oeff, J., Leusmann, T., and von Wehren, S.: ZuMoBau-ZL – providing methods to ensure extended lifetime for structures in interim storage facilities, Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-81, https://doi.org/10.5194/safend2025-81, 2025.