Superphénix 1 Steam Generator Fabrication

The Superphénix 750-MW(thermal), once-through-type steam generators are the result of over 10 years of intensive research and development. Detailed design and manufacture of the components lasted from 1977 to 1982. The main difficulties encountered during the construction of these prototype units concerned:

1. demonstration of satisfactory high-temperature properties of Alloy 800 tubes
2. proven resistance of tube welds to thermal fatigue and of structures and shells to sodium/ water reaction effects
3. prevention of the tube bundle to flow-induced vibration
4. necessity of manual welding of shells to prevent hot cracking hazards related to the boron content of the steel
5. welding of heat exchange tubes.

None of these difficulties, however, invalidated initial major design choices, but provided a wealth of technical and technological experience and knowledge for the steam generators of the future. Plans for the future include revision of the specifications (Alloy 800, in particular) and process improvements (tube welding).