Research on the Reliability Tolerance Design Method of Nuclear Safety Analog Signal Isolator

The reliability of analog signal isolators directly affects the operational safety of reactor protection systems. Due to parameter drift of electronic components, the reliability of analog signal isolators will decrease in high-temperature environments. To address this issue, a reliability tolerance design method is introduced. Based on the mechanism of analog signal isolators, an equivalent accuracy model of signal isolators has been established. Various parameters that affect circuit accuracy were selected using orthogonal method, and the signal-to-noise range of the parameters was analyzed. Based on the analysis results, optimization was carried out on the factors that have a significant impact. Through Monte Carlo simulation, it was confirmed that the tolerance design method increased the qualification rate from 93.98% to 99.83%, demonstrating the effectiveness of the design method.