PURPOSE: To form an in-reactor container coolant gravity-circulation system automatically upon stopping of a primary coolant pump by mounting float type valves to the inside cylinder of a reactor container.
CONSTITUTION: The inside of a casing 21 is segmented to upper and lower parts by a partition plate 26 bored with a flow passage hole 24 at about the center. A ball 25 for closing the flow passage hole 24 when a free coolant liquid level 12 on a cold plenum side lowers below the position of the plate 25 is housed in the upper block of the plate 26. The upper block is communicated with the cold plenum side in the lower block of the plate 26. A side flow passage hole 22 and a top flow passage hole 23 are bored to the upper block. Plural pieces of such float type valves are circumferentially provided to the inside cylinder 5. The in-reactor container coolant gravity-circulation system is thus formed upon stopping of the primary cooling pump without using manual operations.
MINAZUKI ISAO
FUJIMORI KOJI
MITSUBISHI HEAVY IND LTD