[en] Full text: Static power coefficient is calculated for the reactor PFBR using ABBN perturbation data. It is calculated as the change in reactivity for a unit change in power from one steady state to the other steady state, keeping all the other reactor parameters like coolant flow and inlet temperature constant. Power coefficient are calculated using the code PREDIS, for all the representative pin using ABBN perturbation data with the corresponding axial and radial core boundary movement worths. Isothermal temperature coefficients are calculated for constant thermal expansion coefficients of fuel and steel. Analysis of unprotected uncontrolled withdrawal of a CSR is done with the ABBN perturbation data and new radial and axial boundary movement worths, with inlet coolant temperature as a varying function of time. From uncontrolled withdrawal of CSR, external reactivity of 1.36 $ is given in 200 s, with the negative feedback reactivity, the resultant net reactivity becomes 0.002 $ at 250s. The peak melt fraction is 28% in the central subassembly, over 40 cm length in core middle, with 0.8% over all fraction of core melt