Fig. 1. Framework diagram of the one-dimensional solidification mechanism model (color online)

Fig. 2. Schematic diagram of the solidification microelement inside the tube (color online)

Fig. 3. Solidification diagram inside the tube (color online)

Fig. 4. Distribution of dimensionless instantaneous solidified layer thickness for Case 1 penetration pipe at the moment before complete blockage of the pipe (color online) (a) Mesh sensitivity analysis, (b) Time step sensitivity analysis

Fig. 5. Distribution of dimensionless solidified layer thickness along the penetration pipe at the moment before complete blockage of the pipe (a) and the comparison of experimental and simulated results (b) (color online)

Fig. 6. Variation of mass flow rate of the primary loop before and after shutdown (color online)

Fig. 7. Temperature evolution (a) and mass flow rate evolution (b) at multiple locations of the reactor after shutdown (color online)

Fig. 8. Evolution of the dimensionless thickness of the solidified layer (δ*) in LWHX tube side at the inlet and outlet (a) and the distribution of δ*in the LWHX tube side at the moment just before the failure time (b)