Scaling analysis for single-phase natural circulation under dynamic motion and its verification using MARS-KS code

Abstract

In designing a thermal–hydraulic facility simulating a floating nuclear power plant, the scaling of dynamic motion is necessary. As natural circulation under motion is a significant phenomenon in floating nuclear reactors, a scaling analysis for single-phase natural circulation was performed, and similarity criteria were derived for inclination, frame acceleration, and rotational motion conditions. The inclination angle can be reduced or maintained in the scaled model with adjustments to the hydraulic diameter and volumetric heat generation. In addition, the amplitudes of acceleration and angle should be maintained in the model under motion, and their periods follow the time scale. Thereafter, the similarity criteria were verified using a system analysis code to simulate virtual test loops of the prototype and scaled-down models for a one-dimensional single-phase natural circulation under various motion conditions. In result, this similarity criteria can be used to design a scaled-down single-phase natural circulation facility under motion conditions.