Doel 3 & Tihange 2 - Some Peer-reviewed Scientific Papers & Reports

J. Koutsk~,K. ~plichal

16

8 - 10ppm after charging at current densities up to 5 0Am -2. On the other hand, strength propert ies of the steel noticeably decreased with higher hydrogen contents after charging at current densities over 100A m -2. For the above-ment ioned specimens irradiated at 130°C to fluence 9 x 1023nm-2 both yield and tensile strengths decreased by ~ 30% compared with hydrogen-free specimens. Hydrogen and radiat ion embr i t t lement may impai r the ductility of the steel. A substant ial decrease in total elongat ion and reduct ion of area o f both irradiated and uni rradiated specimens was observed with hydrogen contents over 2.5 ppm. Up to approximately 2 ppm hydrogen charging at current densities of 1-10 A m -2, no changes in ductility were observed. Above 2 . 5ppm hydrogen and at current densities of 10- 5 0Am -2 there was a marked decrease of elongat ion (Figs 1 and 2), reduct ion in area and fracture stress. The effect of radiat ion embr i t t lement on hydrogen embr i t t lement was inversely correlated with irradiat ion temperature (Fig. 2). Wi th decreasing irradiat ion temperature the current density showing the greatest rate of decrease of elongat ion and reduct ion in area moved towards the lower values of current densities and the downward slope of the elongat ion-dens i ty curve increased.

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0,8 1 10 H2 [ ppm] Elongation As of irradiated and unirradiated CrMoV steel as a function of h y d r o g e n c o n t e n t . 2 5

Fig. 1.