Launch of BWR Core Heat Transfer Experiments with use of High Pressure Thermal-Hydraulic Loop (HIDRA)
—Experimental Investigation of Core Cooling Performance under Severe Thermal-Hydraulic Conditions—
An evaluation of the influence of a severe accident in nuclear reactor should be based on the understanding of complicated physical phenomena that may occur during the accident, one of which includes the understanding of the heat and mass transfer or fluid motion in the nuclear reactor (thermal hydraulic phenomenon).
High pressure thermal-hydraulic loop (HIDRA), a newly constructed facility for this experiment that ensures the realization of high pressure conditions (at pressure up to 12MPa), is a general-purpose, high-temperature/pressure thermal-hydraulic loop that implements experiments for intended purposes, by rearranging its test section according to each condition. With this system, we have started core heat transfer experiments simulating not only high thermal loads and severe cooling conditions, but also oscillating flows that may occur in the accident of a boiling water reactor (BWR).
This experiment relates to the core cooling performance that a BWR should have in preparation for the event of an anticipated transient without scram in a multiple failure condition , of which analysis is required by the new regulatory standards. HIDRA allows for the experimental simulation of severe thermal-hydraulic conditions that were not well taken into consideration by any existing experiments.
Elucidation of the mechanism of related thermal-hydraulic phenomena using this experimental results is expected to further sophisticate evaluation techniques for the core heat transfer of a BWR, as to help make engineering judgments in future safety regulations.