Steam raising unit heated by the cooling gas of a nuclear reactor

A blower is fitted above the steam raising unit. The hot gas is supplied to the steam raising unit formed as a helical bundle from below, where the hot gas is first taken downwards through an annular duct and enters the heating bundle with an even speed. The annular duct is sealed with a sliding seal in the upward direction, which also acts as earthquake support. In order to make access to the feedwater and live steam pipe possible at the blower situated at the top, these two pipes are taken laterally out of the cold gas area and through the pressure vessel. Due to the special fixing of individual pipes of the heating bundle in vertical plates and the presence of an expansion zone for the return pipes, thermal differential expansion can be kept small. (orig./HP)