2. Capacity sizing methods

2.1 Experimental data

The rules currently in force in nuclear industry construction codes (such as the RCC-M or ASME standards) are based on the analysis of experimental data. Numerous tests, most of them carried out in the 1970s and continued today in new configurations, have contributed to understanding, analyzing and developing tubular bundle dimensioning rules with regard to vibration risks caused by flows.

One of the major vibratory risks for a tube bundle is that of fluidelastic instability, observed when the flow velocity exceeds a certain threshold, which can lead to tube rupture in a very short time! Current design rules are based on the estimation of a critical flow velocity U*, calculated as :