In this work, new designs for coincidence neutron detection systems were proposed and assessed with different neutron detectors (3He, Ar and BF3) and calculations. Each system consists of 42- neutron detectors arranged in two rings. The simulated systems include special nuclear material (SNM) with changing the neutron sources such as; AmLi, AmBe and 252Cf. The aim of this work is the determination of the coincidence system efficiency and neutron distribution fluence for each proposed system in active mode with a changing of neutron detectors arrangement. The results of the proposed systems were studied and compared to the active-well neutron coincidence counter (AWCC) which is employed in uranium testing using the code Monte Carlo N-Particle eXtended (MCNPX) version 2.7.0. The systems that were suggested fell within the energy range of 0-0.025 KeV, which is the thermal neutron region. The results proved that we could advocate implementing any of the presented ideas to replace AWCC because no single model outperformed the others.