SCADOP: Phenomenological modeling of dryout in nuclear fuel rod bundles

In this paper, a phenomenological model as indicated above is presented. The model incorporates a new methodology to estimate the Initial Entrained Fraction (IEF), i.e., entrained fraction at the onset of annular flow. The incorporation of this new methodology is important since IEF is often assumed ad-hoc and sometimes also used as a parameter to tune the model predictions to experimental data. It is highlighted that IEF may be low under certain conditions against the general perception of a high IEF due to influence of churn flow. It is shown that the same phenomenological model is applicable to tubes as well as rod bundles. For application to rod bundles, the flow field was calculated using subchannel methodology. The model developed has been validated against experimental data in tubes and rod bundles. In the process a computer code SCADOP has been developed for analysis of dryout in rod bundles.