DYLAM (Dynamic Logical Analytical Methodology) and its related methodologies are reviewed and found to have many favorable characteristics. Previous studies have shown that the DYLAM methodology represents an appropriate tool to study dynamic analysis. A hybrid model which is a synthesis of the DYLAM model, a system thermodynamic simulation model and a neural network predicative model, is implemented and used to analyze dynamically the CANDU pressurizer system. This study demonstrates that the hybrid model for system reliability analyses is effective.