Patent ID: 7835482

Claim:
An emergency core cooling system for a BWR plant not including external recirculation piping, comprising: an active emergency core cooling system consisting of only a first safety division and a second safety division, each of said first and second divisions including a high-pressure motor-driven core cooling system, and a low-pressure motor-driven core cooling system, which is commonly used as a residual heat removal system, a heat removal capacity of said residual heat removal system being not less than 100% of the necessary capacity to cool the core and the containment to meet a safety requirement at a design basis loss of coolant accident; a first emergency power supply equipment provided for the first safety division, the first emergency power supply equipment configured to supply electricity to the first safety division; and a second emergency power supply equipment provided for the second safety division, the second emergency power supply equipment configured to supply electricity to the second safety divisions; wherein said emergency core cooling system does not include additional safety divisions that contain an active emergency core cooling system, and wherein said emergency core cooling system meets the safety requirement at a design basis loss of coolant accident considering a single failure of any active components including said first or second emergency power supply equipment.