The assessment involved in the selection of Alloy 800 as the material for the liquid-metal fast breeder reactor (LMFBR) steam generators particularly embodies the following criteria:

  1. mechanical properties at high temperatures, creep resistance, creep ductility, and variation of these properties with regard to the microstructure of the alloy
  2. fabricability of different components (tubes, plates) and their weldability
  3. corrosion resistance in normal service conditions (water-steam and clean sodium) or in abnormal conditions (contaminated media).
Alloy 800 has been used already in the construction of different prototypes, one of which has an output of 45 MW(th) and was tested in the Electricité de France (EdF) test station of C.G.V.S. Renardieres. These prototypes, which are made with industrial products (tubes, plates) have demonstrated satisfactory behavior for several thousand hours of service. The investigations were conducted especially by the Fives-Cail Babcock Company and the EdF—Commissariat à l’Energie Atomique Working Group on LMFBR materials. The investigations have resulted in the selection of a range of chemical compositions and heat treatments that provide an optimization of the mechanical properties in service.