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Microstructural Evolution of Welded Stainless Steels on Integrated Effect of Thermal Aging and Low Flux Irradiation

  • Martin BjurmanEmail author
  • Kristina Lindgren
  • Mattias Thuvander
  • Peter Ekström
  • Pål Efsing
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)

Abstract

The combined effect of thermal aging and irradiation on cast and welded stainless steel solidification structures is not sufficiently investigated. From theory and consecutive aging and irradiation experiments, the effect of simultaneous low rate irradiation and thermal aging is expected to accelerate and modify the aging processes of the ferrite phase. Here, a detailed analysis of long-term aged material at very low fast neutron flux at LWR operating temperatures using Atom Probe Tomography is presented. Samples of weld material from various positions in the core barrel of the Zorita PWR are examined. The welds have been exposed to 280–285 °C for 38 years at three different neutron fluxes between 1 × 10−5 and 7 × 10−7 dpa/h to a total dose of 0.15–2 dpa. The aging of the ferrite phase occurs by spinodal decomposition, clustering and precipitation of e.g. G-phase. These phenomena are characterized and quantitatively analyzed in order to understand the effect of flux in combination with thermal aging.

Keywords

Thermal aging Irradiation Weld ferrite Spinodal decomposition Stainless steel 

Notes

Acknowledgements

The authors wish to express their sincere gratitude to Mr. Roger Lundström, who performed specimen extraction and light optical microscopy, and Anders Jenssen for fruitful discussions, both from Studsvik Nuclear AB. EPRI have kindly allowed use of the material. The work was funded by the Swedish Radiation Safety Authority, the Swedish NPPs Materials Group (SUMG) and Studsvik Nuclear AB.

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Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  • Martin Bjurman
    • 1
    • 2
    Email author
  • Kristina Lindgren
    • 3
  • Mattias Thuvander
    • 3
  • Peter Ekström
    • 4
  • Pål Efsing
    • 1
    • 5
  1. 1.Royal Institute of Technology (KTH)StockholmSweden
  2. 2.Studsvik Nuclear ABNyköpingSweden
  3. 3.Chalmers University of TechnologyGothenburgSweden
  4. 4.Swedish Radiation Safety AuthoritySolnaSweden
  5. 5.Ringhals ABVäröbackaSweden

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