DEVICE AND METHOD FOR CONTROLLING FLOW VIBRATION OF GAS-LIQUID TWO-PHASE FLOW IN NUCLEAR REACTOR, AND METHOD FOR CIRCULATING COOLANT OF NATURAL CIRCULATION TYPE BOILING WATER NUCLEAR REACTOR USING METHOD THEREOF

PROBLEM TO BE SOLVED: To achieve a structure controlling flow vibration in a channel wherein a gas-liquid two-phase flow goes up. SOLUTION: A tubular chimney 11 is provided to an upper lattice plate 10 of a core 9 of a natural circulation type boiling water nuclear reactor. The chimney 11 is sectioned into a plurality of upright channels to form a lattice channel 16. One or a plurality of stirring devices 1 or drifting devices 20 are provided inside the lattice channel 16, and the gas-liquid two-phase flow coming up from the core 9 is stirred/mixed or drifted inside the lattice channel 16. Thereby, a flow state of the gas-liquid two-phase flow flowing inside the lattice channel 16 is changed into a mixing state or a flow state of a drift state from a flow state of a churn flow by an annular flow, and the pressure fluctuation load generated in the flow state of the churn flow is controlled. COPYRIGHT: (C)2007,JPO&INPIT