“…The simplest option (Merle-Lucotte et al, 2008) is to only modify the original effective delayed neutron fraction b eff byb eff in the conventional point kinetic equations, while the equations for the effective delayed neutron precursors are the same as those for solid-fuel reactors. A more complex model (MacPhee, 1958) leads to modification of the calculating procedure for computing effective delayed neutron precursors c i (t), in which equations for the effective precursors are modified in order to account explicitly for their decay out of the core. Rineiski et al proposed a general model, in which the spatial distribution of the precursors is modeled and then the effective precursors (employed in the point kinetic part that serves for accelerating spatial kinetic calculations) are computed by averaging these spatial distributions while using the adjoint neutron flux as weighting function (Rineiski et al, 2005).…”