Research on the oscillation characteristic of thermal–hydraulic parameters for natural circulation conditions of small pressurized water reactors under rolling condition

The ocean conditions of stormy waves, especially the rolling motion condition, have a large impact on the natural cycle operation of small integrated pressurized water reactors. The thermal–hydraulic parameters will fluctuate drastically and deviate from the original equilibrium position. For this small integrated pressurized water reactor, its thermal–hydraulic models of the primary and secondary loops are developed. And the calculation module under the rolling motion condition is supplemented. On this basis, the effects of rolling condition on the steady-state operation of the natural circulation and the conversion process from forced circulation to natural circulation are analyzed. “The factor of oscillation characteristic under rolling condition” is proposed to quantitatively evaluate the fluctuation characteristics of the parameters. The results show that an increase in the angular acceleration of the rolling makes the parameter oscillations more violent. Although the angular acceleration is small, the large-angle and large-period rolling has a greater effect on the parameters. The results can provide a basis for the analysis of the operating characteristics and optimization of the control scheme of a small integrated pressurized water reactor under the rolling condition.