Fig. 1. Comparison of experiment values and simulation values under different working conditions

Fig. 2. Framework of neutronics-material-thermal-hydraulics coupling

Fig. 3. Flowchart of Newton-Krylov algorithm

Fig. 4. Geometry configuration of the single rod

Fig. 5. Dynamic changes of key coupling parameters over time under standard operating condition (a) Average thickness, (b) Maximum thickness, (c) Average removal thickness, (d) Average temperature, (e) Maximum temperature, (f) k_inf

Fig. 6. Distribution contours of thickness of the oxide layers under standard operating condition (a) Thickness contour of magnetite layer, (b) Thickness contourof Fe-Cr spinel layer

Fig. 7. Dynamic changes of key coupling parameters over time under different oxygen concentrations (a) Average thickness,(b) Maximum thickness, (c) Average removal thickness, (d) Average temperature, (e) Maximum temperature, (f) k_inf

Fig. 8. Distribution contours of thickness of the oxide layers for 10 000 h under different oxygen concentrations (a) Thickness contour of magnetite layer, (b) Thickness contour of Fe-Cr spinel layer