Fusion materials research started in the early 1970s following the observation of the degradation of irradiated materials used in the first commercial fission reactors. The technological challenges of fusion energy are intimately linked with the availability of suitable materials capable of reliably withstanding the extremely severe operational conditions of fusion reactors. Although fission and fusion materials exhibit common features, fusion materials research is broader. The harder mono-energetic spectrum associated with the deuterium–tritium fusion neutrons (14.1 MeV compared to <2 MeV on average for fission neutrons) releases significant amounts of hydrogen and helium as transmutation products that might lead to a (at present undetermined) degradation of structural materials after a few years of operation. Overcoming the historical lack of a fusion-relevant neutron source for materials testing is an essential pending step in fusion roadmaps. Structural materials development, together with research on functional materials capable of sustaining unprecedented power densities during plasma operation in a fusion reactor, have been the subject of decades of worldwide research efforts underpinning the present maturity of the fusion materials research programme. For achieving proper safety and efficiency of future fusion power plants, low-activation materials able to withstand the extreme fusion conditions are needed. Here, the irradiation physics at play and fusion materials research is reviewed.

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Materials research for fusion

Developing structural, high-heat flux and plasma facing materials for a near-term DEMO fusion power plant: The EU assessment

https://isiarticles.com/bundles/Article/pre/pdf/10567.pdf

Recent progress of R&D activities on reduced activation ferritic/martensitic steels

Materials RD for a timely DEMO: Key findings and recommendations of the EU Roadmap Materials Assessment Group

Development of new generation reduced activation ferritic-martensitic steels for advanced fusion reactors

Mechanical properties and TEM examination of RAFM steels irradiated up to 70 dpa in BOR-60

Quantitative TEM analysis of precipitation and grain boundary segregation in neutron irradiated EUROFER 97

Modeling of helium bubble nucleation and growth in neutron irradiated boron doped RAFM steels

Kinetics and thermodynamics of Cr nanocluster formation in Fe-Cr system

Characterization of irradiation induced microstructural evolution is essential for assessing the applicability of structural steels like the Reduced Activation Ferritic/Martensitic steel EUROFER 97 in upcoming fusion reactors. In this work Transmission Electron Microscopy (TEM) is used to determine the defect microstructure after different neutron irradiation conditions. In particular dislocation loops, voids and precipitates are analyzed concerning defect nature, density and size distribution after irradiation to 15 dpa at 300 °C in the mixed spectrum High Flux Reactor (HFR). New results are combined with previously obtained data from irradiation in the fast spectrum BOR-60 reactor (15 and 32 dpa, 330 °C), which allows for assessment of dose and dose rate effects on the aforementioned irradiation induced defects and microstructural characteristics.

https://publikationen.bibliothek.kit.edu/1000056369/3918865

C. Dethloff

Papers

Mechanical properties and TEM examination of RAFM steels irradiated up to 70 dpa in BOR-60

Quantitative TEM analysis of precipitation and grain boundary segregation in neutron irradiated EUROFER 97

Modeling of helium bubble nucleation and growth in neutron irradiated boron doped RAFM steels

Kinetics and thermodynamics of Cr nanocluster formation in Fe-Cr system

Microstructural defects in EUROFER 97 after different neutron irradiation conditions