Assessment of CCFL Model of RELAP5/MOD3 against Simple Vertical Tubes and Rod Bundle Tests. International Agreement Report

摘要

The Counter Current Flow Limitation (CCFL) model used in RELAP5 /MOD3 version 5m5 has been assessed against simple vertical tubes and rod bundle tests performed at a facility of Korea Atomic Energy Research Institute. The effect of changes in tube diameter and nodalization of tube section were investigated. The roles of interfacial drags on the flooding characteristics are discussed. Differences between the calculation and the experiment are also discussed. A comparison between model assessment results and the test data showed that the calculated value lay well on the experimental flooding curve specified by user, but the pressure jump before onset of flooding was not calculated.