DIRECT VESSEL INJECTION BYPASS FLOW: EXPERIMENT AND ANALYSIS

摘要

A great deal of experimental and analytical studies were performed so far for the cold leg injection (CLI) so that its flow behavior can be predicted and the safety injection system be designed well enough. On the other hand it is difficult to design the direct vessel injection (DVI) system for the Korean Next Generation Reactor (KNGR) due mostly to lack of readily applicable experimental data and code analysis. Tests were performed to measure the emergency core cooling (ECC) water bypass in this work. A new type of flooding correlation is presented based on the Kutateladze correlation. A theoretical model is suggested to determine the amount of the ECC water bypass. The measured amount of the bypass water is consistent with the model prediction and is found to be nearly independent of the injected ECC water. Optimization of the KNGR ECC design can be achieved by way of optimization of the geometrical design of the DVI lines because the amount of the ECC water bypass is nearly independent of the amount of the injected ECC water according to the result of the present experiment. Rather the degree of bypass is strongly dependent on the geometrical configuration of the DVI system. It is thus concluded that the main idea of designing the KNGR DVI system must start with the geometry, not with the system parameters.