Calculation of emergency core cooling system flow rates at Wolsong plants

As the Wolsong plants consist of two separated loops and the pressure behavior is different from each other, the amount of flow injected from emergency core cooling system may be either splitted between two loops or provided into the lower pressure loop, which is unique to Wolsong plants. A stand-alone program has been developed to predict the ECCS flow between two loops at Wolsong plants and tested for various conditions. The pressure drop inside the ECCS pipe mainly depends on frictional loss due to flow and an iteration technique is used to accommodate flow split between two loops and the characteristic curve of emergency core cooling pumps