Research on flow characteristics of once-through steam generator in rolling motion

Owing to its compact structure, the once-through steam generator(OTSG)is used widely in integrated Pressurized Water Reactor(PWR) The casing OTSG in concentric annuli tube is a new type of steam generator which applies double sides to transfer heat. The water of the secondary side goes through complicated phase change processes, and the flow pattern and heat transfer cases are much more complex than those of the natural circulation steam generator used in PWR. It is necessary to study their steady-state and dynamic characteristics. By means of THEATRe code which was based on the two-phase drift flux model and was modified by adding module calculating the effect of rolling motion, the casing OTSG simulation model in rolling motion was built. It can describe the parameters change in every section of OTSG accurately in rolling motion, and can embody dynamics characteristics from different aspects. By comparing the operational data in different rolling amplitude and rolling period, flow operational characteristics and principles were analyzed. The results can be used to analyze the thermal-hydraulics characteristics of the integrated PWR in rolling motion.