Steady State and Transient Operation of a Natural Convection Decay Heat Removal System in a LMR Model

摘要

Steady state and transient measurements were executed in the KIWA chain of natural convection which is a 1:10 model of all relevant parts of a liquid metal cooled reactor (LMR) to study the decay heat removal. The paper shows results of the steady-state campaign with the reactor core running at decay heat level, of the steady-state campaign for the stand-by conditions with the core at full power, and the transient campaign with initially full power and the change to decay heat level as the pumps run down and the reactor scram is activated in consequence of a loss of service station power. The apparatus was found to perform according to design specifications without any flow reversal in the decay heat removal system, even under unfavorable conditions. For the transient series, the paper discusses the influence of the way the only active elements, the air louvers, are opened. The paper mentions also some hypothetical cases with a lack of potential to remove the decay heat.