PSI - Issue 54

Oleksii Ishchenko et al. / Procedia Structural Integrity 54 (2024) 241–249 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 5. Numerical model (FEM) of RVI and simplifications.

3.1. FEM and approximate calculation scheme results In Fig. 6-Fig. 7 calculated deformations and stresses opposite to broken nozzle for both models are shown. It can be seen that FEM with plastic hardening gives greater deformations and stresses at that point. Considering that the smallest distance between CB and RPV at the point near inlet nozzle is equal 190 mm, and the maximum deformations in FEM are up to 40 mm, we can conclude that the gap will not be closed and cooling will be provided. Note that the largest deformations occur in the first 0.1 second in both models, and then it goes down to zero in the elastic model, in elastic-plastic FEM we obtain residual deformation of 27mm.

Fig. 6. Maximum displacements (a) approximate shell theory; (b) FEM Ansys Transient.