Inner vessel in reactor assembly of pool type fast reactor separates hot and cold pool sodium. The shape of inner vessel is optimized with reduced upper & lower shell diameters and toroidal redan for future Fast Breeder Reactor (FBR). This results in higher buckling strength and reduced thickness and hence reduced weight. To achieve the intricate toroidal shape with specified dimensional tolerances, a comprehensive technology development exercise was undertaken for the manufacture of inner vessel sector. This paper discusses the details of development activities carried out towards manufacture of large size die and punch involving a number of trials, cold forming of sector of inner vessel, comprehensive global & local profile measurement using swing arm & other templates, and non-destructive examination. The achieved profile of the redan meets the specified dimensional and other design requirements. The successful completion of technology development activities for manufacture of a sector of inner vessel with innovative design features has demonstrated the indigenous manufacturing capability and given confidence for the design improvements incorporated.

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