[en] Thermal hydraulic analysis of primary pump pipe rupture event have been carried out with the objective of (i) estimating the temperature rise in the fuel, clad and coolant, (ii) investigation of possible flow redistribution in subassemblies and (iii) investigation of the formation of vapour bubble due to flashing resulting in reactivity addition in the core. For this purpose one dimensional studies using thermal and hydraulic models of the core SA and primary sodium circuit, three dimensional studies of grid plate using CFD code PHOENICS and one dimensional studies using pressure transient codes have been carried out. Analysis indicates that core flow is reduced to 30% during the transient and specified temperature limits of this category of events are respected. There is no flow redistribution among various subassemblies and formation of vapour in subassemblies. (author)