AbstractThe qualitative behavior of the solutions of a reaction‐diffusion system arising in the theory of nuclear reactors is investigated by means of singular perturbation techniques, the small parameter ϵ representing the inverse of neutron velocity. At the lowest approximation for small ϵ the solutions exhibit oscillations about the unique strictly positive equilibrium, much as in the case of the associated lumped parameter system. A two‐times representation for solutions of small amplitudes is also