“…For example, CCFL may take place in the steam generator of a pressurized water reactor (PWR) during a reflux-cooling mode, and therefore, CCFL correlations are required to evaluate the flow rate of liquid flowing into the reactor core. Hence we have been investigating the CCFL characteristics in vertical pipes (Kusunoki et al, 2015(Kusunoki et al, , 2016Murase et al, 2016) and proposed some CCFL correlations (Kusunoki et al, 2015), which account for the effects of the fluid properties on the CCFL characteristics. The correlations were however obtained by a purely empirical manner.…”