In hybrid reactors where fusion is based on a dense plasma focus (DPF), neutron return from the fission region to the fusion chamber can cause significant wear on the plasma focus device. To mitigate this effect, a shield has been designed based on the difference in neutron reaction cross sections. The shield is designed to be as transparent as possible to high-energy fusion neutrons while relatively preventing the return of neutrons to the fusion chamber. Among the proposed materials, 6Li exhibited the best performance.