Fuel pin transfer tool

A fuel pin transfer tool for use in withdrawing a fuel pin from or placing a fuel pin in a fuel pin assembly submerged in water in a tank, said tool including a tubular housing of such length that it may be suspended by means located above the water with a portion of the housing extending downwardly in the water in vertical alignment with and spaced a predetermined distance above a selected one of the fuel pins of the assembly or the location therein for a fuel pin, a first rigid axially movable means within the housing, an axial latching device connected to the lower end of said means including a collet member provided with a plurality of resilient fingers normally spaced apart for the free reception of the head end of a fuel pin, a sleeve member surrounding said fingers, one of said members connected to said axially movable means and the other member movable axially relative to said one member between upper and lower positions, said fingers and said sleeve member including surfaces that are mutually engageable and shaped to cam said fingers into a relationship for gripping the received end of a fuel pin when said axially movable member is in one of said positions, said fingers in their pin-receiving relationship when said axially movable member is in the other of said positions, axially located, resiliently compressible means having upper and lower ends, backing means above said fingers connected to said axially movable means and backing said lower end, said other member connected to said backing means in a manner establishing the upper and lower positions thereof, a connection between the upper end of said resilient means and said other member, said other member in the upper position thereof holding said resilient means under compression against downward movement unless a predetermined downward force is exerted against the connection capable of overcoming the resistance of said resilient means and to move said other member into the lower position thereof whereby said resilient means normally prevent axial movement of said other member, first operator controlled means operable to reciprocate said first axially movable means between upper and lower positions spaced apart a distance such that a stroke is provided of a length such that said latching device may be advanced into a position below the lower end of the housing in which a fuel pin is either to be released in or withdrawn from the assembly and a withdrawn pin at least partly received within the housing, second rigid axially movable means above said connection and a second operator control operable to drive said second axially movable means downwardly into such engagement with said connection as to exert said predetermined downward force thus to so move said other member as to enable said fingers to return to their normal relationship.