Contact

Dr. Eberhard Altstadt

Head
Structural Material­s
e.altstadtAthzdr.de
Phone: +49 351 260 2276

Porträt Dr. Kaden, Cornelia; FWOM

Dr. Cornelia Kaden

c.kaden@hzdr.de, c.heintzeAthzdr.de
Phone: +49 351 260 3431

orangener PfeilPublications

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Vorschau-Bild

Structural Materials

The safety of nuclear reactors critically depends on the mechanical behavior of structural materials under harsh environmental conditions (neutron irradiation, high temperatures). In the framework of the program NUSAFE (Nuclear Waste Management, Safety and Radiation Research) of the Helmholtz Association we characterize irradiated reactor materials from the nm-scale to the macro-scale. Our focus:

  • Long-term irradiation effects in reactor pressure vessel steels of running and new-build reactors in the context of lifetime extension
  • Assessment of the irradiation tolerance of innovative materials for future reactor concepts including nuclear fusion (e.g. ferritic/martensitic Cr-steels, oxide dispersion strengthened (ODS) steels, the emerging class of high-entropy alloys)

The methodical spectrum co­vers the full functional chain from nm-scale irradiation-induced defects to macroscopic mechanical properties and aims at the identification, better understanding and mitigation of irradiation effects. The new insight substantially contributes to the scientific background for the safety assessment of nuclear reactors. The research relies on a unique infrastructure including the hot cell labs for the investigation of neutron-irradiated materials as well as the HZDR Ion Beam Center for ion irradiation experiments.

Our expertise:

Current projects

  • Innovative structural materials for fission and fusion
    (INNUMAT, EU, HORIZON-EURATOM, 2022-2026)
  • European Database for Multiscale Modelling of Radiation Damage
    (ENTENTE, EU-H2020-Euratom, 2020-2024)
  • Fracture mechanics testing of irradiated RPV steels by means of sub-sized specimens
    (FRACTESUS, EU-H2020-Euratom, 2020-2024)
  • Structural Materials research for safe Long Term Operation of LWR NPPs
    (STRUMAT-LTO, EU-H2020-Euratom, 2020-2024)
  • Untersuchungen zum Ausheilverhalten von Reaktordruckbehälterstählen bei niedrigen Temperaturen
    (WetAnnealing, BMWI, 2020-2025)
  • Physical modelling and modelling-oriented experiments for structural materials 2
    (IOANIS2, EERA-JPNM Pilote Project, 2023 - 2027, coordinator HZDR)
  • In-situ experiments for nuclear applications
    (INSITEX, EERA-JPNM Pilote Project, 2023 - 2027)
  • On the use of small punch as high-throughput screening technique to extract mechanical properties of ion irradiated materials
    (SHERPA, EERA-JPNM Pilote Project, 2023 - 2027)

Latest Publication

Recovery of neutron-irradiated VVER-440 RPV base metal and weld exposed to isothermal annealing at 343 °C up to 2000 hours

Altstadt, E.; Bergner, F.; Brandenburg, J.-E.; Chekhonin, P.; Dykas, J.; Houska, M.; Ulbricht, A.

Abstract

Neutron irradiation causes embrittlement of reactor pressure vessel (RPV) steels. Post-irradiation annealing is capable of partly or fully restoring the unembrittled condition. While annealing at high temperatures (e.g. 475 °C) was successfully applied to extend the lifetime of operating VVER-440 reactors, the benefit of annealing at lower temperatures (e.g. 343 °C – the maximum to which the primary cooling water can be heated) is a matter of debate. In this study, neutron-irradiated VVER-440 RPV base metal and weld were exposed to isothermal annealing at 343 °C up to 2000 hours. Given the limited amount of material, the degree of recovery was estimated in terms of Vickers hardness, the ductile-brittle transition temperature derived from small punch tests, and the master curve reference temperature derived from fracture mechanics tests of subsized samples. For the base metal, small-angle neutron scattering was applied to underpin the findings at the nm-scale. We have found significant partial recovery in both materials after annealing for 300 hours or longer. The variations of the degree of recovery are critically discussed and put into the context of wet annealing.

Keywords: reactor pressure vessel steel; embrittlement; wet annealing; recovery; hardness; small punch test; fracture mechanics; small-angle neutron scattering

Related publications

Permalink: https://www.hzdr.de/publications/Publ-39192

Team

Foto: Gruppenbild der Abteilung

Head

NameBld./Office+49 351 260Email
Dr. Eberhard Altstadt801/P1512276
e.altstadtAthzdr.de
Dr. Cornelia Kaden801/P1023431
c.kaden@hzdr.de, c.heintzeAthzdr.de

Employees

NameBld./Office+49 351 260Email
Dr. Frank Bergner801/P1503186
f.bergnerAthzdr.de
Dr. Paul Chekhonin801/P1462149
p.chekhoninAthzdr.de
Vanessa Dykas801/P1053363
v.dykasAthzdr.de
Mario Houska801/P1482242
m.houskaAthzdr.de
Jens Pietzsch801/P0322814
3550
jens.pietzschAthzdr.de
Dr. Andreas Ulbricht801/P1463155
a.ulbrichtAthzdr.de
Tilo Welz801/P0322814
t.welzAthzdr.de