Patent ID: 9031183
Filing Date: 2015-05-12
Classification: G21C,G21D,Y02E

Abstract:
1. An emergency core cooling system provided for a boiling water reactor plant comprising: three safety divisions for an active safety system, each of said safety divisions including a high pressure core cooling system having no less than 100% of the injection capacity required for cooling a reactor core at a design basis accident, a low pressure core cooling system having no less than 100% of the injection capacity required for cooling the reactor core at the design basis accident, a residual heat removal system, which is commonly used as the low pressure core cooling system, having no less than 100% of a heat removal capacity required for cooling the reactor core and a containment vessel at the design basis accident, and an emergency power supply source for feeding electric power to the high pressure core cooling system, the low pressure core cooling system, and the residual heat removal system; and at least one safety division for a passive safety system including an isolation condenser that cools and safely shuts down the reactor core for no less than 8 hours without replenishing cooling water even when a fire in a first safety division for the active safety system, a single failure in a second safety division for the active safety system and online maintenance in a third safety division for the active safety system occur simultaneously, wherein the active safety system does not include a pre-stage booster pump of which failure can cause a loss of whole function of one safety division.