Optimization of the strategy of filling steam generators with a mobile feed water source during an SBO event

One of the important AM measures in the event of a complete loss of power supply for self-consumption, fully implemented on the VVER-440/V213 units operated by SE, a.s. in the Slovak Republic after the accident at the Fukushima Dai-ichi NPP, is the possibility of replenishing feed water to steam generators with a high-pressure mobile source. This mobile power supply acts as an autonomous diversity backup to the project safety system of super-emergency power supply for steam generators and is classified as a so-called FLEX category device. However, during emergency conditions, when the use of such equipment is required, it is necessary to take into account the optimal use of human capacities in the management of the event in question. Based on this requirement, an optimized method of using the high-pressure mobile feed water source of steam generators in such situations was proposed and its technological sufficiency was demonstrated by a specific thermo-hydraulic computational analysis using the code APROS 6. (author)