| 摘要 |
An apparatus (100) for tensioning a hold down beam of a nuclear reactor jet pump inlet mixer (38) is configured to be inserted in a confined annulus between a core shroud and a reactor vessel of a nuclear reactor. The hold down beam (52) includes a beam body (56), a pair of opposed beam tabs (58) and a pair of opposed beam trunnions (60) extending outwardly from the beam body, and a threaded beam bolt (62) received within a threaded channel extending through the beam body. The tensioning apparatus (100) includes a housing (102) having a lower base plate (106) and an upper support plate (104) positionable over the body of the hold down beam, rotatable trunnion engaging members (120) for engaging the beam trunnions (60), reciprocating members (112) coupled to the upper support plate and lower base plate for engaging the inlet mixer (38) adjacent to the beam trunnions (60), and an actuator (128, 140) mounted between the upper support plate and lower base plate and extending through the lower base plate for selectively actuating the trunnion engaging members (120). Tensioning of the hold down beam is accomplished by positioning the hold down beam on an upper surface of the inlet mixer with each beam tab under an inlet riser bracket (54) of the jet pump (32). The tensioning apparatus is then placed over the hold down beam, followed by rotating the trunnion engaging members into engagement witht the trunnions, extending the reciprocating members to engage the inlet mixer and to force the beam tabs against the inlet riser brackets to thereby extend an opening between the hold down beam and the upper surface of the inlet mixer, rotating the beam bolt to extend the bolt into contact with the upper surface of the inlet mixer, and removing the tensioning apparatus from engagement with the tensioned hold down beam. |
