Reflooding Phenomena in a Single Heated Rod : Part 1, Experimental Study

抄録

Reflooding in a loss of coolant accident involves unsteady and very complicated phenomena such as quenching. In this study the reflooding is examined using a simple apparatus with a single electrically heated rod. The purpose of this paper is to present qualitative examinations relating to the phenomena during reflood, and to obtain ascending speed of the quench front and heat transfer coefficient during transient. the results are as follows : (1) A boiling region can be divided into two main parts. One is a film boiling region which occupies the greater part of the boiling region. The other is a nucleate boiling region appearing in a small area around the quench front. (2) The heat transfer coefficients of a film boiling region and a nucleate boiling region are about tens to hundreds and more than thousand kcal/m²h°C, respectively. (3) The quench front advances upward at a nearly constant speed when the inlet coolant temperature is as low as 20°C.