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

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3.4 RUSSIAN STUDIES

Russian studies have looked at the conjoint effect of hydrogen and irradiation on the embrittlement of reactor pressure vessel steel by using round tensile specimens (Krasikov, 1974; Alekseenko et al., 1977) or fracture mechanical test specimens (Mazel et al., 1978, 1980, 1983). Tensile tests have looked at the strengthening effect of irradiation and the connections of hydrogen embrittlement by using hydrogen content of about 5 cm 3 H/100 g Fe, as shown on Table 4. Hydrogen causes small changes in the mechanical properties, which recover fast even at room temperature.

Table 4. Tensile test results of 12Cr2MoVA (48TS-3) pearlitic steel irradiated and/or hydrogen charged (Krasikov 1974). 1 cm 3 H / 100 g Fe = 0.899 ppm H.

*Determined only for unirradiated specimens

Alekseenko et al. (1978) studied the hydrogen embrittlement of l5Kh3MPA steel irradiated (2 x 10 20 and 1 x 10 20 n/cm 2 , E > 1 MeV, in temperatures 100-150°C and 300-350°C) with hydrogen content of 7-10 cm 3 H/100 g Fe by measuring the threshold stress of the delayed fracture during the continuous hydrogen charging (among other factors). Figure 27 shows that steel is not susceptible to a delayed fracture after a hydrogen charging. The fracture strength of the irradiated steel is 50 kp/mm 2 lower than that of the unirradiated steel. If the hydrogen charging continues during the test, the steel is susceptible to delayed fracture, which also depends on the density of the cathodic current (Figure 28). The decrease of the reduction of area at fracture of the notched test specimens accelerates, when the stress exceeds about 0.7 x R m , as seen in Figure 2.