Unterrainer, Raphael

Gambino, Davide

Semper, Florian

Bodenseher, Alexander

Torsello, Danielle

Laviano, Francesco

Eisterer, Michael

2024-08-29T11:55:51Z

2024-08-29T11:55:51Z

2024-05-02

<div class="csl-bib-body"> <div class="csl-entry">Unterrainer, R., Gambino, D., Semper, F., Bodenseher, A., Torsello, D., Laviano, F., &#38; Eisterer, M. (2024, May 2). <i>Correlating the Deterioration of the Superconducting Properties of CCs by Neutron Irradiation with Small Defects</i> [Conference Presentation]. 9th International Conference on Superconductivity and Magnetism, Fethiye - Ölüdeniz, Turkey. http://hdl.handle.net/20.500.12708/200014</div> </div>

http://hdl.handle.net/20.500.12708/200014

Recently published simulations have shown that reactor designers of compact fusion devices will face major issues concerning the expected lifetime of their magnet systems. While a commercially feasible reactor should ideally be affordable, robust and on top of that compact, currently available data suggests that compact reactor designs, relying on coated conductors will face major costs and downtimes to exchange their centerpiece on a regular basis. This is obviously in contradiction to two of the three above proposed advantages of these systems. Considering future improvements in shielding technology and that these designs are still in their infancy and may change in size, a lifespan of 10 years may be feasible but could be an upper limit for the magnets. This raises the question how and if the radiation resistance of coated conductors can be improved. To answer this question, however, it is necessary to understand which types of defects degrade the superconducting properties to subsequently develop mitigation strategies or inherently more resistant conductors. We irradiated commercial coated conductors based on Gadolinium-Barium-Copper-Oxide (GdBCO) in our TRIGA MARK II fission reactor to work out which types of defects are responsible for the degradation of the critical current Jc and temperature Tc of coated conductors. The fission reactor spectrum is believed to resemble the expected fusion spectrum if the samples are shielded from the thermal peak (Ekin < 0.55 eV) with a neutron absorber material such as Cadmium. By irradiating samples with or without shielding, it is possible to introduce distinct defect landscapes to the superconductor. This is enabled by the utilization of a defect formation process where Gd isotopes possessing a large absorption cross section for thermalized neutrons, lead to the formation of small mainly oxygen defects upon the absorption of a slow neutron. By comparing the results of these two irradiation techniques, we are able to distinguish between the contribution of small defects versus large cascades on Jc and Tc. The data shows similarities in the degradation behaviour of the superconducting properties despite the different introduced defect landscapes. Consecutive annealing experiments in pure O2 atmosphere revealed identical recovery rates at increasing temperatures. These results strongly suggest that the defects responsible for the degradation of the superconducting properties are of the same type. Since the defect formation process in the thermal neutron experiments is well understood and the energy of the primary knock-on-atom (PKA) is known to be approximately 30 eV, it is possible to simulate the expected defect structures by molecular dynamics simulations. Further studying the defect classes with DFT allows us to make an estimation on their influence on the local DOS of the CuO2 planes and thus on their degrading effects on the superconducting properties.

European Commission

en

superconductivity

REBCO

neutron irradiation

radiation resistance

annealing

frenkel pairs

Correlating the Deterioration of the Superconducting Properties of CCs by Neutron Irradiation with Small Defects

Presentation

Vortrag

Linköping University, Sweden

Polytechnic University of Turin, Italy

Polytechnic University of Turin, Italy

101052200

Conference Presentation

invited

High-temperature superconducting materials for fusion magnets. The partner project is KKKÖ ME

TRIGA Mark II-Nuklearreaktor

C1

M4

Computational Materials Science

Non-metallic Materials

50

50

E141-06 - Forschungsbereich Low Temperature Physics and Superconductivity

0000-0002-8720-9004

0000-0002-7763-7224

0009-0003-6212-0657

0000-0002-2959-1962

0000-0001-9551-1716

0000-0002-5271-6575

0000-0002-7160-7331

9th International Conference on Superconductivity and Magnetism

27-04-2024

04-05-2024

On Site

Event for scientific audience

Fethiye - Ölüdeniz

TR

Unterrainer, Raphael

Multi Track

Physik, Astronomie

1030

100

Publications

en

no Fulltext

conference paper not in proceedings

http://purl.org/coar/resource_type/c_18cp

restricted

European Commission

0000000000

E141-06 - Forschungsbereich Low Temperature Physics and Superconductivity

Linköping University

E141-06 - Forschungsbereich Low Temperature Physics and Superconductivity

E141-06 - Forschungsbereich Low Temperature Physics and Superconductivity

Polytechnic University of Turin

Polytechnic University of Turin

E141-06 - Forschungsbereich Low Temperature Physics and Superconductivity

0000-0002-8720-9004

0000-0002-7763-7224

0009-0003-6212-0657

0000-0002-2959-1962

0000-0002-5271-6575

0000-0002-7160-7331

E141 - Atominstitut

E141 - Atominstitut

E141 - Atominstitut

E141 - Atominstitut