Detection of special nuclear material (SNM) hidden in cargo containers is considered to be one of the major challenges for homeland security. SNM impose a significant threat for public safety since they can be converted into nuclear weaponry and used for potential terrorist attacks. In this paper we present who we can fill the existing gap in quickly but accurately detecting hidden SNM. Synergism of Monte Carlo methods and intelligent control paradigm provides a novel frame for automated cargo interrogation and final decision making. Human operator is assumed to not be the part of the procedure while the powerful detection algorithms are used with fuzzy logic tools to indicate whether the container should be singled out for manual search or not. In this paper the general frame of our so called iMASS (intelligent Model Assisted Sensing System) is presented.