5-9 September 2016
Prague Congress Centre
Europe/Prague timezone

P1.111 Implementation of ferritic steel as in vessel wall: Lessons learnt and followed up

5 Sep 2016, 14:20
1h 40m
Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Foyer 2A (2nd floor), 3A (3rd floor)

Prague Congress Centre

5. května 65, Prague, Czech Republic
Board: 111
Poster F. Plasma Facing Components P1 Poster session

Speaker

Irene Zammuto (Max Planck Institut für Plasmaphysik)

Description

ASDEX Upgrade (AUG) is the only tokamak in Europe to have low activation ferritic steel in the inner vessel wall. The project is a first step towards the extensive use of ferritic steel in future fusion reactors. The ‘ad hoc’ ferritic steel built with low activation capability is the so called Eurofer. As the low activation property is not a requirement for AUG, the material selected for the project is the martensitic steel P92 which is the most similar material to Eurofer from a magnetic point of view. The purpose of the project is to improve understanding of the magnetic perturbation of the ferritic steel both on the plasma and magnetic probes, evaluating and controlling these effects. Bearing this in mind, in 2013 a step wise program has been started and part of the graphite tiles in the region of the inner column with steel tiles were replaced [1]. The first campaign did not suffer any particular problem related to the new material, but the inspection of the machine pointed out some hardware problems. The graphite tiles adjacent to the steel tiles were damaged. To justify the failure mode inside the vessel, a hypothesis was made and FEM analyses were carried out in this direction. With extreme caution, in 2015 just one additional steel row was added together with diagnostics that confirmed the hypothesis. Now that a clear understanding of the problem has been reached, the project could be continued. For the next campaign it is planned to replace all the tiles in the middle region of the heat shield together with stiffening and modification of the supporting structure. In this paper the learning process from the damage of the tiles and its causes, from the FEM analysis results to the data diagnostics will be reported.

Co-authors

Albrecht Herrmann (Max Planck Institut für Plasmaphysik, Garching bei München, Germany) Arne Kallenbach (Max Planck Institut für Plasmaphysik, Garching bei München, Germany) Irene Zammuto (Max Planck Institut für Plasmaphysik, Garching bei München, Germany) Louis Giannone (Max Planck Institut für Plasmaphysik, Garching bei München, Germany) Stefan Vorbrugg (Max Planck Institut für Plasmaphysik, Garching bei München, Germany) Team Asdex Upgrade (Max Planck Institut für Plasmaphysik, Garching bei München, Germany)

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