Calculation of reactivity and power factors depending on the external source location

We used the neutron diffusion equation with external neutron sources, in cartesian geometry and the two groups of energy, to verify the influence of external neutron source locations in the calculation of reactivity and power factors. To this end, the Coarse Mesh Finite Difference (CMFD) method was applied to the adjoint flux calculation and to simplify reactivity calculation in PWR type reactor, using the output of the Nodal Expansion Method (NEM). Different locations on the two-dimensional plane, as well as different types of fuel elements in the reactor core were used in the present study. ► Neutron diffusion equation with external neutron sources was used. ► Nodal expansion method was used to obtain the neutron flux. ► CMFD method was applied for the adjoint flux and reactivity calculation. ► The influence of external source location at reactivity calculation was verified. ► The results were obtained for different locations on the two-dimensional core.