2002 年 68 巻 668 号 p. 1073-1079
This report (3rd Report) shows an advanced estimation method of the fluidelastic instability for the U-bend tube bundle of steam generators in Japan, which is subjected to steam-water two-phase flow. The criterion is based on the usual Connors' formula, where many parameters are estimated with newly measured data and with an advanced thermo-hydraulic code (shown in 1st Report). Some measured data, which are required for the criteria, are shown here, added to the critical factor (shown in 2nd Report). Safety margin is introduced for the design to avoid the severe damage, compared with measured U-bend instability and an example of a practical event.