The hardening and embrittlement of RPV-steels is of great concern in the actual NPP life assessment. This embrittlement is caused by irradiation-induced damage. The current procedure to estimate material properties for the irradiated pressure vessels is based on Charpy-V tests. But the reason for the embrittlement of the materials is not yet known. The real nature of the irradiation damage should thus be examined as well as its evolution in time.
Fe-Cu binary alloys are often used to mimic the behaviour of such steels. More recently the influence of manganese and nickel in low-Cu RPV-steels has become a significant topic. Thus in contrast with the existing models in the literature, where it is predicted that the hardening saturates after a certain dose, alloys containing nickel and manganese irradiated at SCK•CEN showed a continuing increase of the hardening. PAS-analyses show that the main objects causing hardening are most probably interstitial clusters decorated with manganese in the Cu-free alloy. While in the RPV-steel and Fe-CuMnNi alloy, the main effect is still due to Cu-rich precipitates at low dose, but the role of manganese becomes pre-dominant at high dose.
|Title of host publication||Structural Materials for Innovative Nuclear Systems (SMINS)|
|Place of Publication||Paris, France|
|State||Published - 25 Jul 2008|
|Event||Workshop on Structural Materials for Innovative Nuclear Systems (SMINS) - OECD NEA NCS in cooperation with the International Atomic Energy Agency, Karlsruhe|
Duration: 4 Jun 2007 → 6 Jun 2007
|Conference||Workshop on Structural Materials for Innovative Nuclear Systems (SMINS)|
|Period||2007-06-04 → 2007-06-06|