Abstract: An apparatus and method for plugging an access hole in a steam generator, having a shell, a wrapper, and an annulus positioned between the shell and the wrapper, includes attaching a plate, having a first mating connection and at least one aperture, to the wrapper of the steam generator. A plug, having a second mating connection and at least one aperture, is positioned within a bore of the plate. The plug is rotated approximately 90.degree. for engaging the first mating connection of the plate with a second mating connection of the plug and for aligning the aperture of the plug with the aperture of the plate. A sleeve, having a bore therethrough and at least one aperture, is positioned on the plug and the aperture of the sleeve is aligned with the apertures of the plate and the plug. A pin is installed in the aligned apertures of the plate, the plug, and the sleeve. A retaining nut is positioned on the plug after installation of the sleeve.

Abstract: Methods and apparatus that improve flashover voltage levels in turbine-generators, and reduce the spacing between the end portion connections of one phase group and the end portion connections of neighboring phase groups provide a semiconducting layer on the inside surfaces of insulation that surrounds such stator coil connections. At least one of the metallic connectors which join the end portions in each phase group is electrically coupled to this semiconducting layer, such that discharge between the metallic connector and the insulation surrounding its associated phase group are prevented.