Relationship between organizational factors, safety culture and PSA in nuclear power plant operations

There are four nuclear safety imperatives or ''4Ms'': machine (hardware, design, QA/QC), milieux (operating conditions, environment, natural phenomena), man (human reliability) and management (organizational and management influences). Nuclear safety evaluations as well as evolution of its most powerful tool, Probabilistic Safety Assessment (PSA), followed chronologically the 4M constituents. The nuclear industry worldwide, and the nuclear safety regulators in particular, have been preoccupied with the first M almost to the point of obsession with belated and only intuitive interest in the third and fourth M (human dimension). Human factors or economics in the nuclear industry was an afterthought. Human reliability was essentially born in the aftermath of the Three Mile Island (TMI) accident. Impact of organizational factors on nuclear safety is only in the early stages of R and D. This paper describes some of the concepts being pursued by APG to link organizational factors and safety culture to Human Reliability Analysis (HRA) and to integrate such into probabilistic safety assessment (PSA), e.g. [APG, 1993]. (author). 11 refs, 4 figs, 1 tab