Application of hydrogen embrittlement models to the blister growth behavior in 12Cr2MoNbVB steel and alpha-Fe exposed to low-energy d plasma

Processes of blisters and associated subsurface cracks nucleation during exposure of 12Cr2MoNbVB ferritic-martensitic steel and alpha-Fe under glow discharge hydrogen (deuterium) plasma with ion energies of approx 1 keV and ion fluencies up to 2 centre dot 10²⁴ D/m² at various temperatures have been examined. The methods used were scanning electron microscopy, thermal desorption spectroscopy and the D(³He, p)⁴He nuclear reaction. Temperature dependence of average blister diameter, the deuterium depth distribution and retention were studied. Application of hydrogen induced cracking models was considered to assess the effects of hydrogen from the plasma on the development of blisters and subsurface cracks. Based on this analysis, it is shown that significant crack growth rates can occur during reactor shut-down periods when the temperature of the structure decreases to less than about 373 K.