| 摘要 |
PURPOSE:To increase inflow of coolant into a water rod and cool a fuel rod sufficiently by making dual structure of the water rod arranged in the center part and upwardly providing an upper orifice for coolant inflow and outflow on an end plug for closing the upper end of an outside tube. CONSTITUTION:In the operation of a reactor in which an fuel assembly 1 having a water rod 3b is charged a core spray system is automatically operated and a large quantity of spray water of the fuel assembly is sprayed in the case where coolant is lost by the accident in which the tubing for circulating the coolant is broken. The spray water 24 reaches the upper surface of the water rod 3b and flows therein from an upper orifice 10 holed on an end plug 31. The spray water 24 flowed in an inner tube 29 becomes steam flow 25 and the steam flow 25 rises in the inner tube 29, while the spray 24 flowed in a circular space 32 between the inner tube 29 and an outer tube 30 flows down along the inner walls of the inner tube 29 and the outer tube 30 and cools the surface of the water rod 3b. The spray water 24 is separated from the steam flow 25 and the rod 3b can smoothly be cooled because the flow is not interrupted. |
