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.

Inner vessel in reactor assembly of sodium cooled 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 carried out successfully for the manufacture of inner vessel 30° sector. The achieved profile of the redan meets the specified dimensions and other design requirements. Spring-back observed in the sector was small. To verify the developmental exercise results, a finite element analysis (FEA) of forming of inner vessel sector was performed on finite element software ABAQUS. In this paper, FEA results and spring back are discussed. Spring back assessed is maximum at the center and relatively lower towards the edges for the redan with the chosen radius of 5980 mm.

Sodium to sodium heat exchanger tubes are small in diameter, long and thin. These tubes are supported at intermediate locations and subjected to compressive and tensile loading during reactor operation. Structural mechanics analyses of a 2-D axi-symmetric model of heat exchanger was performed to estimate the load sharing in these tubes during reactor operation on finite element software ABAQUS. Since the tubes are suppoted at intermediate locations, a 3D model of full tube with intermediate support was made to calculate the critical buckling load and buckling modes. In this paper, structure analysis of heat exchanger and load sharing in tubes, critical load for tube and buckling modes in the tube, and design check of tubes under compression are covered. Tubes which are under compression are checked for buckling and found within the design limit.

In PFBR, Intermediate Heat Exchanger (IHX) is used to transfer heat from Primary Sodium to Secondary Sodium. A scaled down model of PFBR IHX has been designed as per design code rules of RCC-MR. In this scaled down model, main portion of IHX like tube sheets, tubes and down comer are designed innovatively. The ligament efficiency and radial & circumferential hole pattern are simulated for top & bottom tube sheets. A 2D Axis-symmetric finite element model of the scaled down model has been made and detailed structural analysis has been carried out via software called CAST3M. Design and development of a scaled down model to simulate the deformation as well as stress distribution realistically, establishing the test setup and procedures for causing crack initiation and depicting the enhanced understanding of RCC-MR design procedures of tube sheets specific to heat exchanger are the novel features of this paper.