Study of the establishment of severe accident experimental facility - A study on the condensation phenomena at the inner wall of a nuclear reactor containment in a severe accident.

摘要

The condensation heat transfer on the inner wall of nuclear reactor containment should be predicted accurately in order to analyze the safety in a severe accident. The heat transfer coefficients were measured for steam/air condensation on a vertical wall. The parameters considered were air-mass fractions(W=0.0, 0.1, 0.2, 0.3, 0.5, 0.7), mixture vapor velocities (U(sub in)=1.4, 3, 5, 7 m/s) and condensate film Reynolds numbers (Re(sub f) ; up to 18000). The overall heat transfer coefficients were from several hundreds to several thousands (W/m(sub 2) K) in the present experimental range and increased from several tens to about two hundreds percents experimental range and increased from several tens to about two hundreds percents with the increase of film Reynolds number. This is because the waves of condensate film enhance the heat and mass transfer in the noncondensable gas layer of bulk vapor as well as in the condensate film. By using the non-dimensional analysis of a falling-film condensation on a vertical wall, the overall heat transfer coefficient was separated into the film-side and the vapor-side heat transfer coefficient. The present results of pure steam condensation was proposed for the film-side heat transfer coefficient of steam/air heat transfer coefficient. The present results of pure steam condensation was proposed for the film-side heat transfer coefficients was developed as a function of air-mass fraction, vapor Reynolds number, condensate-film Reynolds number, Prandtl number, and Schmidt number. The correlation includes the enhancement of the heat and mass transfer in the noncondensable gas layer due to the wavy interface. 69 refs., 7 tabs., 60 figs. (Author)