Neutrons drive fusion research forward

Fusion research reactors require heat-resistant wall materials. Researchers have investigated a promising candidate with neutrons at the MLZ.

This is not a picture by an Impressionist painter. It shows the orientation of the crystal structure in steel, as measured by the researchers. © FRM II / TUM

This is not a picture by an Impressionist painter. It shows the orientation of the crystal structure in steel, as measured by the researchers. © FRM II / TUM

The walls of a fusion reactor require materials that can withstand extreme conditions. However, when iron is exposed to high-energy radiation, small pores form. The researchers solved this problem by adding some chromium and traces of other elements. However, these precipitate at high temperatures or under neutron bombardment and impair the heat resistance of the alloy, among other things.

Steel samples examined with neutrons
Dr. Andreas Ulbricht and Dr. Frank Bergner from the Helmholtz-Zentrum Dresden Rossendorf treated steel samples with high-energy neutrons to better understand how these precipitations occur. They then examined the samples with Dr. André Heinemann from the Helmholtz-Zentrum Hereon at the SANS-1 instrument of the Heinz Maier-Leibnitz Zentrum.

Dr. André Heinemann prepares a sample at the SANS-1 instrument of the MLZ. © Bernhard Ludewig, FRM II / TUM

Dr. André Heinemann prepares a sample at the SANS-1 instrument of the MLZ. © Bernhard Ludewig, FRM II / TUM

What influence do high temperatures have?
SANS-1 emits neutrons with low energy, which are scattered by the precipitations and thus allow conclusions to be drawn about the type and size of the deposits. This enabled the researchers to better understand the influence of higher chromium concentrations and different temperatures on the material’s properties.
The results will enable researchers to develop better materials for safe operation in the future.