Emergency cooling apparatus for a pressure tube-type reactor system

When the reactor has a failure, a large quantity of cooling water must be fed quickly and accurately to the core. Atomic fuel is supplied to the pressure tube arranged in lattice form. The primary cooling water flowing in the pressure tube is distributed by an undersite header. The high pressure water conduit from the high pressure tank is connected to a jet nozzle opened in the cooling water reserve tank. The cooling water in the tank is absorbed in accompanying action with the cooling water injected from the jet nozzle. The mixed cooling water is conducted to the undersite header through a pipe arrangement. When the pressure tube has a break-down, the signal of a sudden decrease in pressure of the primary cooling water system causes valves to open simultaneously. The injection of high pressure water into the tank from the jet nozzle causes the water in the cooling water tank to be absorbed in accompanying action, thus compensating the water loss from the damaged pressure tube. Furthermore, the above arrangement allows the water in the fuel reservoir to be supplied to meet the emergency, providing a large quantity of cooling water. Thus, the high pressure water tank can be safely maintained by providing a large quantity of cooling water and quickly feeding the water to the core. (Ishida, M.)