Steam generator flow instability modeling. Topical report Sep 79-Jun 80

The steam generator, pressure drop versus flow rate instability during a loss-of-coolant accident in a nuclear reactor is investigated. The steam generator is simulated by flow tubes, each with a different height, on top of a two dimensional quarter circle inlet plenum. This work deals with only a adiabatic air-water system. Both the flow distribution and the overall pressure drop have been studied. The pressure drop versus inlet superficial gas velocity curve and the liquid flow distribution in tube array are measured together with a flow regime map. The flow distribution can be conservatively estimated by the proposed model based on a single average tube pressure drop. When applying the present results to an actual reactor accident calculation, the effects of non-condensable gas, the system effect of relative flow resistance of each steam generator to that of reactor core will have to be taken into consideration also