Contact

Dr. Eberhard Altstadt

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

Dr. Cornelia Kaden

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

Publications

Hot Cell Testing Facilities

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

Validity of Toughness Measurements From Miniature Specimens Failing in Different Fracture Modes

Ortner, S.; Sanchez, M.; Echols, J.; Cicero, S.; Chekhonin, P.

Abstract

Using miniature compact tension (mini-C(T)) (4mm thick, 0.16T) specimens to determine
toughness in reactor pressure vessel (RPV) steels permits the ductile-to-brittle transition
temperature to be derived from small amounts of material and allows more effective use of
surveillance specimens. However, questions have been raised as to whether the failure
mechanisms are the same in miniature and large specimens, something that must be ensured
when transferring fracture results obtained in mini-C(T) specimens to larger components.
This work, performed within the FRACTESUS project, presents toughness measurements
and detailed fractography on both a homogeneously brittle base metal and a relatively
ductile, inhomogeneous weld to assess the transferability of fracture data. The fractography
shows that brittle fracture initiates within the part of specimen experiencing small-scale
yielding (SSY), so long as the toughness measurement is valid. Similarly, although the
precrack front asymmetry appears more marked in smaller specimens, as long as the
deviation from planarity is within the American Society for Testing and Materials (ASTM)
E1921 limits, the asymmetry does not affect the location of the initiation site. For materials
showing a variety of fracture modes, the fracture modes observed at the initiation sites are
consistent with those observed in larger specimens. Where data are available, the stress and
strain conditions at the initiation sites are also found to be consistent in mini-C(T) and larger
specimens. These observations support the thesis that toughness measurements made on
mini-C(T) specimens reflect the same material characteristics and failure mechanisms as
those made on larger specimens.

Journal of Pressure Vessel Technology 146(2024), 051501
DOI: 10.1115/1.4065854

Permalink: https://www.hzdr.de/publications/Publ-39435

More publications

Team

Name	Bld./Office	+49 351 260	Email
Head
Dr. Eberhard Altstadt	801/P151	2276	e.altstadthzdr.de
Dr. Cornelia Kaden	801/P102	3431	c.kaden@hzdr.de, c.heintzehzdr.de
Employees
Name	Bld./Office	+49 351 260	Email
Dr. Frank Bergner	801/P150	3186	f.bergnerhzdr.de
Dr. Paul Chekhonin	801/P146	2149	p.chekhoninhzdr.de
Vanessa Dykas	801/P105	3363	v.dykashzdr.de
Mario Houska	801/P148	2242	m.houskahzdr.de
Jens Pietzsch	801/P032	2814 3550	jens.pietzschhzdr.de
Dr. Andreas Ulbricht	801/P146	3155	a.ulbrichthzdr.de
Tilo Welz	801/P032	2814	t.welzhzdr.de