PSI - Issue 37

M. Annor-Nyarko et al. / Procedia Structural Integrity 37 (2022) 225–232 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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configuration investigated may not pose an immediate safety risk to the integrity of the referenced RPV, but it may accelerate the damage of a highly embrittled ageing RPV.

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Fig. 7. Hoop stress distribution through inlet nozzle- inner RPV wall intersection (path) thickness at different times

Fig. 8: Comparison between M-integral and VCCT K I estimation with fracture toughness of vessel material

5. Conclusion Inadvertent operation of the safety injection systems is a critical anticipated operating transient that may induce significant PTS loadings in a PWR pressure vessel. In this study, a proposed simplified Abaqus-FRANC3D co simulation method is applied to evaluate the integrity parameter (SIF) from the fracture mechanics analysis of an ageing PWR subjected to PTS induced by inadvertent actuation of the SIS. The main conclusions from the study are summarized below: 1. The applied direct thermal-mechanical finite element method estimated the PTS temperature and internal pressure loads concurrently, as opposed to the sequential coupling methods adopted in many studies. This is a simpler approach in the estimation of stresses in complex geometries. 2. The computational cost, number of assumptions and boundary conditions are drastically reduced using this co-simulation method for executable and reliable 3-D FE fracture mechanics analysis of RPV submodels. 3. The integrity parameter, K I calculated with M-integral and VCCT methods at the deepest crack tip were in good agreement. This confirms the accuracy of the proposed co-simulation method. This work serves as a foundation for our future study on the crack growth analysis and fatigue life prediction of ageing RPV induced by AOO PTS loadings. Acknowledgements This work was supported by the National Natural Science Foundation of China [Grant No. 51379046]; Natural Science Foundation of Heilongjiang Province [Grant No. E2017023]; and the International Atomic Energy Agency [FS-INT 1801254]. References

Altair, 2014. Altair HyperMesh. Altair Engineering Inc, USA.