The Improvement of the Wall Temperature Calculation Procedure for the Post-Crisis Region of the NPP Heated Channels

Abstract

The reliable wall temperature prediction is important for the analysis of operation and safety of both nuclear reactors and direct-flow steam generators with high-temperature fluids. The onset of dangerous temperature excursion is possible in the post-crisis region of the heated channels when the inverted annular or the dispersed flow regime occurs. The wall temperature calculations for both flow regimes are represented. The data of Hammouda, Lapperiere, Chen, Miropolsky, Bennett and some other investigators were processed. The obtained average error and deviation are less than those which take place when special best estimate computer code KORSAR is used. Specified result was reached by the way of the engineering procedures correction and may be applied for the closure correlations improvement which is needed in two-fluid two-phase flow models. The conclusion is made that the correct choice of the integration step and the method of the critical quality determination produce effect on the adequate wall temperature prediction.