Abstract: A gas circulator, e.g. for circulating a coolant gas in a nuclear power station, the circulator comprising a shaft (34) rotatable about its axis, circulation blades (54, 56) mounted adjacent one end of the shaft for rotation in the coolant gas, a first bearing, (32), in the form of an active magnetic bearing adjacent one end of the shaft, a seal mounted around the shaft between the first bearing and the blades to prevent the circulating fluid from entering the first bearing, a second bearing (32) in the form of a fluid lubricated bearing spaced from one end of the shaft and a motor to rotate the shaft, the second bearing having a journal bearing portion and an axial thrust bearing portion.