Method to estimate communication error probabilities based on speech acts for nuclear power plants

Communication errors contribute to safety in nuclear power plants (NPPs), yet they are not explicitly analyzed in conventional human reliability analysis. This limitation makes it challenging to estimate communication error probabilities (CEPs), which play a significant role in understanding human failure events. Current approaches rely on qualitative assessments or lack statistical foundations, impeding the quantification of CEPs in both intra-organizational and inter-organizational communication. To address this, this study proposes a speech act–based method for estimating CEPs in NPP operations. In this method, communication is categorized into five speech acts—Request, Report, Declaration, Acknowledgement, and Recovery—and a procedural communication sequence diagram is developed to model communication sequences, with a specific equation introduced for CEP calculation. To support this calculation, speech act error probabilities are estimated through statistical analysis of observations on simulator training for intra-organizational communication and expert elicitation for inter-organizational communication. A case study was conducted to demonstrate the applicability of the proposed method, analyzing operator failures in starting the high-pressure safety injection system, representing intra-organizational communication, and in deploying a 1 MW mobile gas turbine generator, representing inter-organizational communication. Additionally, performance shaping factors influencing both intra- and inter-organizational CEPs are discussed, providing a foundation for future research.