Abstract
CHF experiments have been conducted using the rod bundles of a narrow triangular arrangement, which simulate the Reduced-Moderation Water Reactor core. The purposes of these experiments are (a) to investigate the parameter effects on critical power, (b) to evaluate the existing correlations, (c) to propose the correlation and (e) to make use of the data for the verification of the numerical analysis code. In this paper, parameter effects on critical power or critical quality were focused as a fundamental understanding. It was found from the comparison between the axially uniform and the double humped power distribution that the critical quality of the double humped one decreases significantly when mass velocity>about 150 kg/m^2s.
