Effect of Strain Rate and High Temperature Water on Deformation Structure of VVER Neutron Irradiated Core Internals Steel

  • Anna HojnaEmail author
  • Jan Duchon
  • Patricie Halodova
  • Hygreeva Kiran Namburi
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)


Components of reactor core internals suffer from Irradiation Assisted Stress Corrosion Cracking. Here is studied 08Ch18N10T austenitic stainless steel acquired from decommissioned NPP Nord Unit 1, VVER 440-230 type in Greifswald, where had been irradiated to 5.2 dpa. The material was tensile tested at 20 °C in air and slow strain rate tested at 320 °C in air and in water. SEM observations of the fracture surface found ductile fracture for the air tests, but areas of intergranular fracture typical of IASCC in the water. This paper emphasizes the microscopic examination from three samples to determine the underlying physical damage processes. TEM observations close to the fractured surface focused to the interaction of dislocations with local radiation damage defects and grain boundaries owing to different test conditions. Determination of local chemical composition around the grain boundaries indicated radiation induced segregation; as well presence of helium gas in voids. The observation of tensile tests found the presence of twinning and regions of strained martensite transformation. The nano features of tests at elevated temperature were tangled dislocations, similar in air and water. No effect of the water environment on the deformation structures was observed.


Austenitic stainless steel Neutron irradiation Radiation damage Slow strain rate High temperature water 



The authors would like to express their sincere thanks to Edita Lecianova and Vit Rosnecky for their support in handling and active sample preparation, especially in the hot-cells.

The presented work was financially supported by the SOTERIA project (EC: No. 661913) and by the Ministry of Education, Youth and Sport Czech Republic project LQ1603 (Research for SUSEN). The work has been realized within the SUSEN project (established in the framework of the European Regional Development Fund (ERDF) in project CZ.1.05/2.1.00/03.0108).


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© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  • Anna Hojna
    • 1
    Email author
  • Jan Duchon
    • 1
  • Patricie Halodova
    • 1
  • Hygreeva Kiran Namburi
    • 1
  1. 1.UJV GroupCentrum Vyzkumu Rez (CVR)HusinecCzech Republic

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