Normal residual heat removal heat exchanger is one of the most important equipment in nuclear power plant. Normal residual heat removal heat exchanger is one of the main equipment of RNS. The main function of normal residual heat removal heat exchanger is to remove the decay heat from the reactor core and reduce the temperature of RCS (Reactor Cooling System) during the second stage of the cold shut down of the power plant. Normal residual heat removal heat exchanger is running continuously during refueling to remove the heat from reactor core and RCS. In additional, there are functions such as refueling tank cooling down inside the containment, closed loop cooling after accident and spent fuel pool cooling.