Effects of Initial Pressure and Length of a Broken Pipe on the Transient Hydraulic Loads Acting on Nuclear Steam Generator Tubes and Supports During Blowdown Following a Sudden Feedwater Pipe Break

This paper investigates the effects of steam generator initial pressure and length of a broken feedwater pipe on the transient hydraulic loads on the pressurized water reactor (PWR) steam generator (SG) tubes and supports during blowdown following a sudden feedwater line break (FWLB). To do this, the transient flow fields inside the SG and the connected broken feedwater pipe are calculated by realistically treating the discharge flow as the sub-cooled water flashing flow. Then, the calculated transient flow field data are used to predict the transient hydraulic loads on the PWR SG tubes and supports for some specified cases where the SG initial pressure or the broken feedwater pipe length are different from each other.