Patent Number: 
Section: claims

1. An alternative circulation cooling method for an emergency reactor core cooling system that is performed at a nuclear power plant that includes a residual heat removal system (RHR) for removing fuel decay heat when a nuclear reactor is shut down and a make-up water condensate system (MUWC) that supplies water from a condensate storage tank into the nuclear reactor, the alternative circulation cooling method comprising:connecting a downstream side of a heat exchanger of the residual heat removal system (RHR) to an upstream side of a MUWC pump of the make-up water condensate system (MUWC); andcooling water from a suppression chamber using the heat exchanger of the residual heat removal system (RHR) and performing nuclear reactor injecting or containment vessel spraying using the MUWC pump. 2. The alternative circulation cooling method according to claim 1, wherein:the nuclear power plant includes a high pressure core flooder system (HPCF) that supplies water from the condensate storage tank into the nuclear reactor; andthe downstream side of the heat exchanger of the residual heat removal system (RHR) is connected to the upstream side of the MUWC pump of the make-up water condensate system (MUWC) using pipes of the high pressure core flooder system (HPCF).