Device for radially supporting the bundle envelope and spacer plates of a steam generator

Device for radial support of an envelope of a tube bundle and spacer plates of a steam generator, said steam generator incorporating a pressure envelope elongated along a given axis, said envelope of said tube bundle being elongated along a same axis and disposed within said pressure envelope so as to leave an annular space between said two envelopes, said spacer plates being positioned at given intervals and transversely to said axis in said envelope of said tube bundle in order to support tubes of said bundle, said device being constituted by abutments traversing a wall of said bundle and fixed to said wall level with said spacer plates, said abutments being distributed over a periphery of each spacer plate in order to radially separate said envelope of said tube bundle from said pressure casing and to exert rigid holding stresses between said spacer plates and said envelope of said tube bundle, said abutments comprising means enabling sliding of said abutments on an inner face of said pressure envelope along said axis and screwing means for varying radial dimensions of said abutments with respect to said axis, each of said abutments being constituted by a first part which comes into contact with said inner face of said pressure envelope, a second part and a third part for coming into contact with a spacer plate, said second part serving as an intermediary between said first and third parts, said first part having a first thread enabling it to be screwed to said envelope of said tube bundle by manipulating means, said abutment sliding means and a second thread, said second part having a first thread for screwing it to said second thread of said first part by manipulating means and a second thread with a direction reverse to said first thread, said third part having a thread enabling it to be screwed to said second thread of said second part and means for exerting said rigid holding stress on said spacer plate.