Reactor cooling systems in a FBR type reactor

Purpose: To surely maintain the isolated state due to nitrogen gas sealing thereby prevent the reaction between liquid sodium and water upon rupture of steam generator heat conduction tubes in the reactor cooling systems of a FBR type reactor. Constitution: A steam back-flow preventive device is disposed between a steam generator and a check valve. The device comprises a partition valve disposed between the generator and the check valve, a steam discharge tube branched from a steam pipeway and a steam discharge control valve intervened to the steam discharge pipe. If rupture occurs in the steam generator heat conduction pipe, a steam drum is separated from the generator and nitrogen gas is sealed, but water may possibly be leaked through the seat of the check valve. In this case, destruction of the nitrogen-seal isolated state by the boiling of the leaked water at a reduces pressure can be prevented by opening the steam release control valve to release the steam into the atmosphere. The partition valve functions to separate the discharge control valve and the steam generator. (Kamimura, M.)