The integration of Grid Plate (which holds the fuel sub assemblies) has been completed with the Primary Pipe and installed inside Main vessel. As per the sequence of erection after integration of Grid plate assembly Inner vessel has been erected over the grid plate. 

     Inner vessel serves as a leak resistant barrier between the hot and cold sodium of primary sodium inside the reactor. It is made up of stainless steel SS 316 LN and consists of a lower and upper cylindrical shell of diameter 12m with a height of 11m joined together by a conical shell called Redan.

      Roof slab forms the top cover for main vessel and supports major components such as main vessel, 2 nos. of primary sodium pumps, 4 nos. of Intermediate heat exchanger, large rotating plugs & small rotating plugs, 4 nos. of Delayed Neutron Detectors, 4 nos. of Safety grade decay heat exchanger and other associated auxiliary equipments. Roof slab weighing about 230MT is a box type structure made of carbon steel plates of diameter 12m with a height of 1.5m interconnected by radial stiffeners and cylindrical shells for the various component penetrations. The Roof slab which forms as a top cover has been erected and welded with Main vessel.