SEMIIMPLICIT MODELING OF CONDENSATION IN THE PRESENCE OF NON-CONDENSABLES IN THE RELAP5 MOD3 COMPUTER CODE/

A methodology is developed for modeling condensation in the presence o f non-condensables based on the stagnant film (couette flow) model. Th e methodology, which is fully compatible with the mathematical represe ntation and numerical solution scheme for the two-fluid conservation e quations in the RELAP5/MOD3 computer code, rigorously treats the coupl ing between the heat and mass transfer processes and allows for implic it treatment of the interphase mass and momentum exchange terms withou t iterations and without adversely affecting the stability of the code 's solution scheme. The RELAP5/MOD3 computer code is accordingly modif ied and is successfully validated against published experimental data.