New steam generators for Embalse NGS - replacement cartridge design, manufacturing and localization issues

Embalse Nuclear Generating Station (Central Nuclear Embalse) was placed in service in 1983 and the life extension outage is currently in progress. Embalse NGS is equipped with four vertical inverted 'U' tube-type Steam Generators (SG) with integral preheater, I-800 tubes and carbon steel internals. Between 2002-2006, NA-SA in consultation with AECL (now SNC-Lavalin Nuclear) assessed the potential for SG life extension; However, degradation of the tube supports (carbon steel broached plate) and U-bend supports due to Flow-accelerated corrosion (FAC) coupled with the plan to increase the plant power output during the life extension of the station, resulted in the strategic decision by NA-SA to replace the Steam Generators. As part of the localization program for major components required for Central Nuclear Embalse life extension program, NA-SA and SNC-Lavalin Nuclear (formely AECL) signed a cooperation and technology transfer agreement to evaluate the capabilities of local suppliers to manufacture the steam generators and steam generator tubing. The scope of the localization program for the Replacement Steam Generator (RSG) and Steam Generator Tubing included qualification of the following suppliers by AECL (now SNC-Lavalin Nuclear) under contract with NA-SA: Industrial Metalurgicas Pescarmona SA (IMPSA) was qualified as the manufacturer and supplier of the replacement steam generator cartridges; Fabricacion de Aleaciones Especiales S.A (FAE) a subsidiary of Combustibles Nucleares Argentinos Sociedad Anonima (CONUAR) was qualified as the manufacturer and supplier of the steam generator tubing. The design documentation for the RSG was prepared by BWXT (Canada) under technology transfer contract to IMPSA. IMPSA developed applicable manufacturing drawings and procedures and manufactured four RSG cartridges. All RSG cartridges are now delivered to Embalse site. This paper concentrates on design and manufacturing challenges (successful qualification of local suppliers, pre-production qualification process etc.) encountered during the manufacturing phase of the project. All RSG cartridges are now delivered to Embalse site and installation is in progress.