Today's technology enables people to build complex systems, such as nuclear power plants, that carry big hazards in them. Consequences of accidents that involve such plants can be severe. Hence, safety is an important issue in design and operation. The attention that has been given to system safety has resulted in an increase of component reliability. An accompanying effect is that in relatively more cases, the human operators contribute to accidental situations. Because of that, the study of the impact of operator behavior on system safety has received more attention during the last decade. One of the achievements that was made, is the development of the CAUse based Behavioral model (CAB model), as a part of the Human Interaction TimeLINE (HITLINE) methodology, which studies the impact of intentional operator behavior on system safety. The CAB model was designed to be used in Probabilistic Safety Assessments (PSAs). It uses knowledge about operating procedures, plant configuration and process behavior to perform a simplified simulation of cognitive processes, and to generate a set of possible operator actions with associated probabilities. To make the CAB model available for use in dynartiic PSA techniques, which include the systematic simulation of a large number of accident sequences, a computerized version of the CAB model, called CAuse based Behavioral SIMulator (CAB-SIM) was developed. The CAB model's mechanisms were translated into computer algorithms. Additionally, some improvements to the model were made. As a case study, the HITLINE methodology was applied to a hypothetical two tank system, using CAB-SIM. CAB-SIM was linked with HITline-SIMulator (HIT-SIM), a model for dynamic PSA, that was developed for this case study. The results of the simulations were incorporated in a simple PSA model of the system, that was developed for the purpose of demonstration. Additionally, CAB-SIM was incorporated in Accident Dynamic Simulator (ADS), an existing simulation model for dynamic PSA. The incorporation process included the coding of proper communication channels between CAB-SIM and ADS, modifying ADS simulation driving mechanism and its existing operator model, and the development of application-specific data, i.e. a system representation for use CAB-SIM. Some elementary results were generated. It is concluded that CAB-SIM is a model that seems to be able to improve the modeling of plant-operator interaction in dynamic PSA techniques, by analyzing the impact of intentional operator behavior on system safety. However, parts of the cognitive process simulation need further investigation; further, to make CAB-SIM applicable for real nuclear power plant PSAs, the quantification of operator errors, which currently contains many subjective elements, needs to be improved.