French steam generator experience: Phenix and beyond

The Stein Industrie steam generator of the 250-MW(e) demonstration fast breeder reactor Phenix comprises three units. Each unit is divided into 12 evaporator modules, 12 super-heater modules, and 12 reheater modules. Twenty-four evaporators are made of 21/4 Cr--1 Mo ferritic steel and 12 are made of 21/4 Cr--1 Mo--1 Nb stabilized ferritic steel. All superheaters and reheaters are made of 321 austenitic steel. Since Oct. 1973, this steam generator has been submitted to a number of startups and shutdowns and some 9000 h of operation at full load without any leak, with an acceptable hydrogen diffusion rate of 0.25 g/h per unit through the single wall of the tubes. The Fives-Cail Babcock steam generator selected for the 1200-MW(e) Fast Breeder Power Plant Super Phenix is comprised of four modules with a 357-tube helical bundle made of Alloy 800 housed in a shell made of an austenitic steel (Type 304 or 316L). The module is rated at 750 MW(th) and weighs 140 tons. Other steam generators made of ferritic steels are considered in the longer range for power plants beyond Super Phenix