摘要

Since the thermophysical properties of water change dramatically at near-critical and pseudocritical point, the instability of natural circulation at supercritical pressure may occur in a loop. To predict the region of instability of natural circulation at supercritical pressure, a test loop was built at Tsinghua University. The paper presents the information of the test loop and a numerical analysis model for the loop. The paper verified the numerical analysis code by experiment results and using the code to analyze the instability of the loop. The paper concludes conclusion that there will be no Ledinegg instability occurring at supercritical pressure in the loop.