Tritium is a valuable raw material for generating energy through nuclear fusion. To prevent its loss in future fusion power plants, the Fraunhofer Institute for Material and Beam Technology IWS and the Max Planck Institute for Plasma Physics (IPP) are developing innovative protective coatings.
The joint research project "TritiumStopp" aims to develop highly effective diffusion barriers that can withstand extreme conditions. The controlled fusion of hydrogen isotopes is seen as a beacon of hope for a clean and safe energy future. Tritium plays a central role as a fuel. Its unintentional leakage from reactor walls or pipelines would not only be expensive, but also safety-relevant. The challenge is as follows: Tritium atoms are so small that they can even pass through metal structures - a phenomenon known as permeation.
Industry-ready PVD technology from the Fraunhofer IWS forms the basis for novel permeation barriers that will prevent tritium losses in fusion power plants in the future. The joint research project "TritiumStopp" with the Max Planck Institute for Plasma Physics (IPP) aims at highly effective barrier layers that can withstand extreme conditions (Photo: Daniel Viol/Fraunhofer IWS)
The controlled fusion of hydrogen isotopes is considered a beacon of hope for a clean and safe energy future.
Layer systems with industrial experience
The focus of the TritiumStopp study is on metallic components, e.g. cables, in which barrier layers are to be used to prevent the diffusion of tritium in the future (Photo: Daniel Viol/Fraunhofer IWS)The "TritiumStopp" project focuses on thin barrier layers that prevent tritium from penetrating. In contrast to previous research approaches, the Fraunhofer IWS is using coating technologies that have already proven themselves in industrial high-performance applications - for example as wear protection on highly stressed tools. "Our coatings are based on established PVD processes and can be applied to real power plant components using industrial-grade technology," explains Dr. Volker Weihnacht from the Fraunhofer IWS.
The researchers are testing various types of coatings - including metal nitrides, oxides and diamond-like carbons - for their barrier effect. The tests are being carried out under conditions that can be expected in fusion power plant operation: mechanical stress, thermal cycling and, in particular, neutron radiation. The aim is not only to demonstrate the short-term protective effect, but also to understand the long-term stability of the coatings.
Focus on material diagnostics and measuring stations
In addition to these tests, the researchers also carry out detailed analyses. "We have many years of experience in tracking how hydrogen isotopes propagate in fusion materials," says Dr. Armin Manhard from the Max Planck Institute for Plasma Physics in Garching. Systematic investigations are carried out at several permeation measuring stations, supported by high-resolution diagnostic methods. The aim is to clarify material-physical relationships and precisely understand the effect of individual process parameters. In addition to the scientific findings, the project aims to provide concrete concepts for transferring the technology to power plant components. "Right from the start, we are thinking about how our results can later be transferred into practice - for example in the form of large-area coatings or integrated protection systems," says Dr. Weihnacht.
Research partners
The Fraunhofer IWS develops innovative materials and technologies for the safe handling of tritium in fusion plants - for example through special surface coatings, tritium barriers and recycling processes. The task of the Max Planck Institute for Plasma Physics (IPP) in this project is to investigate the barrier effect of the coatings, in particular through permeation tests. With its tandem accelerator, it is also responsible for introducing radiation damage into the material and analyzing it using ion beams. The Max Planck Institute for Plasma Physics (IPP) is researching the physical basis for a fusion power plant that is intended to generate energy from the fusion of light atomic nuclei. It operates the ASDEX Upgrade tokamak experiment in Garching near Munich and the Wendelstein 7-X stellarator in Greifswald. IPP's work is embedded in the European fusion consortium EUROfusion. With around 1100 employees, IPP is one of the largest centers for fusion research in Europe.
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Tritium - key fuel for nuclear fusion
The SEM image shows a cross-section of a potential barrier layer of a multilayer system of titanium nitride (TiN) and chromium nitride (CrN) (Photo: Fraunhofer IWS)Tritium is a rare, radioactive hydrogen isotope that, together with deuterium, forms the fuel for deuterium-tritium fusion - the most promising reaction to date for generating energy through nuclear fusion. This reaction delivers a particularly large amount of energy at comparatively low temperatures and is therefore central to the success of future fusion power plants.
Problem: Tritium is hardly available in nature, is radioactive and can penetrate materials or be lost due to its small atomic size - with safety and cost-relevant consequences. Research is being carried out into new materials, processes and technologies to recover tritium efficiently, store it safely and minimize losses - a decisive step towards the practical use of fusion energy.
