Secondary main coolant circuit for a fast reactor

Purpose: To rapidly cool a steam generator without application of excessive thermal shock to the generator by flowing liquid metal in a steam generator facility in a directly opposite to normal flowing direction with an air cooler as a heat sink during the operating time of an auxiliary core coolant circuit. Constitution: A liquid metal pumping pipe connected from an overflow tank by a pumping electromagnetic pump is connected to both the inlet pipe of a secondary main coolant circuit circulation pump and a pipe for connecting the steam generator to the outlet stop valve of the steam generator. When the steam generator is isolated after the reactor scram, by closing the stop valve of the pumping pipe low temperature liquid metal pumped from the tank is fed through the generator and a superheater, is then fed toward the inlet branch of the air cooler, is joined at the branch with the flow from the intermediate heat exchanger, is fed to the air cooler, is thereat removed with the heat retained in the generator, and is eventually returened to the circulation pump. Accordingly, no excessive heat shock occurs at the steam generator facility, but it can prove the safety of the facility structure. (Yoshino, Y.)