PSI - Issue 71

Tapan K. Sawarn et al. / Procedia Structural Integrity 71 (2025) 263–270

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Fig.5. Dependence of maximum bending moment on the β -Zr to oxygen ratio.

Fig.6. Offset displacement as a function of β -Zr to oxygen ratio.

4. Conclusions In this study the maximum bending moment and offset displacement of the clad tubes, which experienced the simulated LOCA integral test in the temperature range of 1000 -1200 °C and soaked for 12 to 19 s, were evaluated by using 4PBT. From the obtained results followings conclusions are drawn: ● All the clad tubes cracked during the 4-PBT at the axial location of rupture opening, which indicated embrittlement due to wall thinning and ingress of oxygen. ● Maximum bending moment and offset displacement both increased with increased β -Zr layer thickness and decreased oxygen content in the β -Zr layer. ● Brittle failure occurred corresponding to 0.59 wt. % oxygen and 95 wppm hydrogen concentration in the prior β -Zr, corresponding to 1200 °C oxidation temperature. ● For the effect of hydrogen on the cladding embrittlement at room temperature more brittle failure data need to be generated. So, in this study the influence of hydrogen on the cladding embrittlement remains in-conclusive.