FBR type reactors

Purpose: To simplify the structure of FBR type reactor using sodium as coolants, by using a main vessel wall cooling system and an auxiliary reactor core cooling system in common. Constitution: In the ordinary reactor operation, coolants of an auxiliary cooling systems flowing into coolant pipes are subjected to heat exchange with primary sodium in a cold plenum present in the annulus portion and, after being warmed, sent to an air cooler and cooled. While on the other hand, when the flowing amount of the primary sodium into the hot plenum is reduced upon reactor scram due to failures in the main coolant cooling system, a sodium inflow window is opened, whereby high temperature sodium within the hot plenum is flown from the sodium inflow window to the annulus portion and then cooled by way of the cooling pipe by the auxiliary cooling system. (Kawakami, Y.)