MIDAS December Seminar - Martin Steinbrück & MirCo Große - 15th December
'High-temperature behaviour of promising accident-tolerant cladding materials' and 'Investigation of hydrogen in zirconium alloys by means of neutron imaging'
This month we are pleased to present a double-bill MIDAS Seminar, with talks by Martin Steinbrück and Mirco Große, both of Karlsruhe Institute of Technology - abstracts for both talks are below.
The seminar will begin at 14.00 (UK time) on Wednesday 15th December. The seminar will take place online, at the Zoom link https://zoom.us/j/92574485529 (passcode 159933).
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High-temperature behaviour of promising accident-tolerant cladding materials
Martin Steinbrück
ATF materials became a hot research topic worldwide after the Fukushima Daiichi accidents. The Karlsruhe Institute of Technology (KIT) is involved in various activities, in particular on the high-temperature characterization of ATF cladding materials. Most of these activities are embedded in international collaborations within IAEA, OECD-NEA, EU as well as in cooperation with industrial partners.
The talk will give a brief overview of the three most promising candidate materials for ATF cladding: 1) Cr-coated Zr alloys, 2) FeCrAl alloys, and 3) SiC fiber matrix composites. The fundamentals of the high temperature oxidation/corrosion mechanisms and the maximum "survival temperatures" of the three systems are discussed. Examples of experiments up to 2000°C in various test facilities are used to illustrate the potential advantages and disadvantages of the new cladding systems..
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Investigation of hydrogen in zirconium alloys by means of neutron imaging
Mirco Große
The large difference between the total microscopic neutron cross sections of hydrogen and zirconium provides a strong contrast between hydrogen-free and hydrogen containing zirconium alloys. The total macroscopic neutron cross section depends nearly linear on the number density of hydrogen in the material. This provide the possibility to measure quantitatively the distribution of the hydrogen by means of neutron imaging with a spatial resolution up to 25 µm. In the presentation ex- and in-situ neutron radiography experiments were described investigating hydrogen diffusion and hydrogen uptake in the temperature range between 900 and 1400°C. Neutron tomography provide the possibility of a reconstruction of the 3D hydrogen distribution in a sample. Examples of the determination of the 3D hydrogen distribution in cladding tubes used in LOCA simulation tests will be shown. Additionally, the presentation will give an outlook about new methodical developments and the advances in the investigations of hydrogen enrichments for instance ahead of a crack tip in a Zircaloy sample as well as discuss the possibilities and limits of the method.
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The monthly MIDAS Seminars, organised by MIDAS team members Ben Jenkins and Rehana Jalil, are a great opportunity to view work both directly relevant and adjacent to the MIDAS programme. The seminars are given by a range of researchers across the world, with a mixture of focuses from academia to industry.
Looking forward to seeing many of you there!