THERMAL PROTECTIVE COOLING SYSTEM OF REACTOR VESSEL OF FAST BREEDER

PURPOSE:To prevent distortion of reactor vessel and vibration of reactor wall cooling liner. CONSTITUTION:Before being heated in a reactor core, low temperature sodium in a low temperature Na pienum 4 flows through a flow-in port 5 into an annular channel defined between a reactor vessel 1 and a reactor wall cooling liner 2. The low temperature sodium ascends, while swirling, along a flow rate distributing/equalizing member (partition 8 or circular pipe 9) disposed spirally on the outer peripheral surface of the liner 2. Consequently, the flow rate is equalized in the peripheral direction and the temperature difference is eliminated perfectly in the peripheral direction of the reactor vessel 1. Furthermore, the liner 2 is reinforced by the spiral member (partition 8 or circular pipe 9) and thereby the rigidity of the liner 2 is enhanced significantly and vibration thereof is prevented.