Development of the APWR+ Natural Circulation test of U-bend tube in SG

Abstract

The safety concept of APWR+ on small LOCA event is adopted to use the Steam Generator (SG) for decay heat removal. Therefore, it is very important to be maintained the natural circulation in primary system on small LOCA event to transfer decay heat from core to SG. The natural circulation of two phase flow with non-condensable gas may be hindered by the siphon brake in the u-bend region of SG. This paper focuses the siphon brake phenomena on U-bend tube, and report the air-water and steam-water with non-condensable gas test results. Also, the two phase natural circulation code CANAC3-3D is verified to use these data.