This paper presents an analysis process targeted for the verification of fault secure systems during their design phase. This process deals with a realistic set of micro- defects at the device level which are mapped into mutant and saboteur based VHDL fault models in the form of logical and/or performance degradation faults. Automatic defect injection and simulation are performed through a VHDL test bench. Extensive post processing analysis is performed to determine defect coverage, figure of merit for fault secureness, and MTTF.