In the current study, a new mass quality correlation was developed for the dispersed flow film boiling (DFFB) regime in a rod bundle geometry during bottom reflood. The new correlation was based on the fundamental conservation equations such that the physics during the reflood process can be adequately captured. It is found that the actual mass quality as well as the vapor drift velocity in the DFFB regime are functions of the void fraction, interfacial heat transfer, vapor superheat, droplet size, quench front location and the fluid properties. The Rod Bundle Heat Transfer (RBHT) reflood tests were used to verify the validity of the new correlation and to determine the coefficients. It was found that the current model is able to predict the two-phase mass quality well within 10% error when compared to experimental data.
