A new methodology for radiation induced real-time fault detection and diagnosis, utilizing FPGA-based architectures was developed. The methodology includes a full test platform to evaluate a circuit while under radiation and an algorithm to detect and diagnose fault locations within a circuit using Triple Design Triple Modular Redundancy (TDTMR). An analysis of the system was established using a fault injection. Additionally a functional gamma irradiation analysis was performed to assess the effectiveness of the method. The detection and diagnosis algorithm was capable of detecting errors by switching dynamically during the analysis of an FPGA. However, only the injected fault test was able to properly diagnose the location of the fault. The results indicate that FPGA radiation induced fault production is dependent upon radiation dose rate. A fully interchangeable and operational testing platform has been established along with an algorithm that detects and diagnoses errors in real-time.