The National Research Universal (NRU) nuclear reactor is one of the world’s largest and most versatile research reactors. NRU began operating in 1957, and is being upgraded as part of AECL’s continuing commitment to operational safety. As part of these upgrades, Probabilistic Safety Assessment studies are being carried out, and it has been recognized that the assignment of Human Error Probabilities is an important part of these studies This paper provides a summary of the Human Reliability Analysis (HRA) method, which has been developed for the identification, quantification, screening and reduction of human errors. This HRA method has been developed from existing methods and revised to take advantage of NRU operational experience. This paper discusses the development of the method, its key features and its testing and evaluation.