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

- 36 -

Figure 27. The effect of irradiation on the delayed fracture for 15Kh3MFA steel. The symbol (o) has been used for unirradiated specimens and the symbol (•) for irradiated specimens (Alekseenko et al., 1977).

The irradiation temperature plays a major role in the delayed fracture. Irradiation at 300- 350°C above a certain current density leads to the increase of the fracture time (Figure 28). In the material irradiated at a temperature of 100-150°C, hydrogen reduces the fracture strength dramatically and it drops to approximately 25 kp/mm 2 (Figure 30). Even if the notch effect is taken into account, the fracture strength is still below the yield strength, as seen in Table 5.