RESUMEN
Objective To put forward reasonable and feasible recommendations aiming at enhancing the application safety of afterloading unit, through studying the human reliability in the emergency response against the source blockage of afterloading unit.Methods Based on the human cognition reliability model, ten operation errors during the emergency response against the source blockage of afterloading unit were analyzed and permissible time widow of emergency response operation were determined.The human error probability was calculated with the execution time of emergency response operation obtained through simulation, observation and recording.Results The operation action, relevant permissible time window and execution time were obtained with the corresponding human error probabilities in the range 0.04 - 0.27.Conclusions The human error model in emergency response against the source blockage of afterloading unit based on HCRmodel is feasible, and provides important reference basis to reduce the occurrence of potential exposure and mitigate the consequence of potential exposure.