JET PUMP AND METHOD FOR SUPPRESSING THE VIBRATION OF THE JET PUMP

摘要

Provided is a jet pump wherein the self-exited vibration in a coupling portion between an inlet mixer tube and a diffuser tube can be suppressed without blocking a structural deformation due to a thermal expansion. Disclosed is a jet pump comprised of an inlet mixer tube which is provided within a nuclear reactor pressure vessel of a boiling-water nuclear reactor, and is connected to a riser tube; and a diffuser tube connected to the inlet mixer tube, wherein a cooling water in the nuclear reactor pressure vessel is forcedly circulated. The jet pump is provided with a sliding joint structure wherein the inlet mixer tube and the diffuser tube are connected to each other by inserting the inlet mixer tube to the diffuser tube from the upper opening of the diffuser tube together with a clearance (S); and a self vibration damping structure, the shape of which is determined so that, when the clearance (S) defined by the outer tube wall of the inlet mixer tube and the inner tube wall of the diffuser tube is being increased or decreased by the vibration of the inlet mixer tube or the diffuser tube, the passage resistance within a clearance passage for the delivered cooling water, which is defined by the clearance (S), is not less than the fluid inertia force in the entirety of the clearance passage.