Nuclear power plant control systems are safety-critical systems whose electromagnetic compatibility (EMC) directly affects operational reliability. Electrical Fast Transient/Burst (EFT/B) interference poses a severe threat to digital interface equipment due to its high-frequency, broadband characteristics, strong transient nature, and high peak voltage. Traditional protection measures, often based on empirical design, suffer from insufficient effectiveness or excessive costs.In this study, an end-to-end analysis framework encompassing source modeling – path optimization – terminal protection is established, and a quantitative design methodology is proposed, providing theoretical support for engineering practice. A case study involving the failure of a digital control system interface card in a nuclear power plant demonstrates that the application of this methodology reduces the maximum interference amplitude received by vulnerable components by 99.93%.This approach provides a theoretical reference for analyzing such interference issues during engineering construction phases and is applicable to other EMC-sensitive fields, including nuclear power applications. Additionally, a comparison of the application of different international standards is presented, along with proposed suggestions for improving equipment design.