Abstract: A diffuser extension sleeve 40 includes: a fixer 41 fixed to an upper portion of a diffuser in which an edge of an inlet mixer 25 is inserted, the inlet mixer 25 guiding circulating water, which is transported from a recirculating pump by pressure, downward along an inner surface of a reactor pressure vessel; a spacer 42 having a lower portion inserted in a gap defined by an outer surface 25a of the inlet mixer and an inner surface 26a of the diffuser; and a support 43 supporting the spacer 42 from the fixer 41 side and guiding movement of the spacer 42 in a longitudinal direction of the inlet mixer 25.

Abstract: The present embodiments provide a jet pump for a boiling water reactor as well as a boiling water reactor equipped with the jet pump, the jet pump being less prone to cause self-excited vibration in the case of both forward leakage flow and backward leakage flow. A jet pump 12 for a boiling water reactor is installed in a reactor pressure vessel of the boiling water reactor. The jet pump comprises a riser pipe 31 coupled to a reactor pressure vessel of the boiling water reactor, an inlet mixer pipe 33 coupled to the riser pipe, and a diffuser 34 coupled to the inlet mixer pipe 33 via a sliding joint 40, wherein the inlet mixer pipe 33 comprises at least one of a tapered lower end 42a with a slope angle of 0??a<2° and an upper taper provided at the gap with a slope angle of 0??b<2°.

Abstract: There is provided a vibration suppressing device for a jet pump which is located in a reactor pressure vessel of a boiling water reactor and provided with an inlet mixer pipe coupled to a riser pipe and a diffuser coupled to the inlet mixer pipe by means of a slip joint. The vibration suppressing device is provided with an extension sleeve disposed on an upper portion of the diffuser of the jet pump and constitutes an extension flow channel on a downstream side of a forward leak flow in a slip clearance formed between an inner peripheral surface of the diffuser and an outer peripheral surface of the inlet mixer pipe, and the extension sleeve has a shape such that the extension flow channel has a region in which a flow channel width thereof is constant over a predetermined or longer length.

Abstract: A steam turbine pipe 1 in an embodiment is a steam turbine pipe in a steam turbine facility. The steam turbine pipe 1 includes: a steam passage 30a that leads steam from a boiler to a steam turbine; and a branching passage 40 that branches off from the steam passage 30a. The steam turbine pipe 1 further includes: a shutoff valve 32 that intervenes in the branching passage 40; and a reduced pipe part 31b that is provided at a part of the branching passage 40 between the steam passage 30a and the shutoff valve 32 and made by reducing a passage cross section of the branching passage 40.