A three regions semi-analytical rewetting model

A two-dimensional semi-analytical three-regions rewetting model is developed for the analysis of rewetting of hot cladding furfaces following a LOCA. The model preserves N terms of the temperature distribution series solution with the expansion coefficients being determined by requiring that the temperature and the axial heat flux be continuous at a number of nodes on the interfaces between the regions. The model includes the effects of decay heat generation and inlet coolant subcooling. The model is used to investigate the effect of heat generation, initial surface temperature, Biot number, degree of subcooling, and incipient boiling temperature on the number of terms required for accurate solution, the boiling length, and the rewetting velocity. The results of the simple approximate analytical one- and two-dimensional models are compared to the results of this model to assess their validity. (orig.)