Apparatus for welding an end plug of a burnable neutronsabsorber rod with a reduced diameter trailing shoulder to a tube.

摘要

A welding apparatus (52) includes a housing (54) defining a welding chamber (56) and an access opening (72) at one end thereof. The access opening (72) allows an end of a tube fitted with an end plug to pass into and from a welding position within the chamber (56). An end stop (60) for supporting the end plug at the welding position is rotatably mounted to the housing and disposed in the chamber opposite from and axially aligned with the chamber access opening. The end stop has an annular collar-like portion adapted to fit over and engage the exterior of the end plug. The end stop also has an inner hollow tube-like portion adapted to fit into a central passage of the end plug and engage the interior of the end plug. The end stop has an orifice adapted to supply flow of inert cover gas into the end plug central passage and therefrom into the tube interior to purge air therefrom. Also, a welding assembly (62) having an electrode (64) with a leading end (90) is mounted on a carriage (100) which, in turn, is mounted on the housing (54) for moving the welding assembly toward and away from welding chamber and thereby moving the electrode leading end toward and away from the tube and end plug between respective extended working position and retracted non-working positions. A drive mechanism (68) is operable to rotate the tube and thereby rotate the tube end and end plug within the welding chamber and therewith the end stop engaged with the end plug.