Comparison of the Irradiation Effects on Microstructure and Mechanical Properties of VVER-Type RPV Steels


Comparison of the Irradiation Effects on Microstructure and Mechanical Properties of VVER-Type RPV Steels

Viehrig, H.-W.; Böhmert, J.; Ulbricht, A.

A German/Russian irradiation experiment has been performed at the pressurised water reactor VVER-70 of the Rheinsberg NPP (Germany). The programme aims at the evaluation of neutron embrittlement and annealing behaviour in dependence on the content of alloying elements and impurities. Charpy V-notch, SENB, tensile, and CT-type specimens have been irradiated.
Specimens have been subjected to instrumented Charpy V impact and fracture mechanical toughness testing according to the ASTM E 1921-97 standard for reference temperature, T0, de-termination. The results of Charpy-V testing were presented on the IAEA Specialist’s Meeting in Madrid 1999. This paper continues the presentation with reference temperature testing and results of microstructural investigations. The microstructure is analysed using SANS technique.
The Charpy-V transition temperature shifts due to neutron irradiation could be confirmed by the reference temperatures T0 shifts. Furthermore, the SANS experiments provide a clear evidence of irradiation-induced microstructural features. Between a microstructural and an embrittlement based radiation coefficient, there is a obvious correlation. The main parameters of influence are the neutron fluence and the nickel content.

Keywords: VVER-type reactor pressure vessel steel; irradiation; irradiation coefficients; Charpy-V parameter; fracture toughness; mechanisms; microstructure; small angle neutron scattering; defects; volume fraction

  • Lecture (Conference)
    Proceedings of the IAEA Specialists Meeting on Irradiation Embrittlement and Mitigation, Gloucester, England, 14-17 May 2001, p. 121-130
  • Contribution to proceedings
    Proceedings of the IAEA Specialists Meeting on Irradiation Embrittlement and Mitigation, Gloucester, England, 14-17 May 2001, p. 121-130

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