The initial causes of serious accidents at nuclear power plants have not so far been flaws in the advanced-technology portion of the plants  Rather, the initial causes have been attributed to human error, as when a worker at the Browns Mills reactor in the United States dropped a candle and started a fire, or to flaws in the plumbing, exemplified in a recent incident in Japan
Such everyday events cannot be thought unlikely to occur over the long run
Now that nuclear power generation has become a part of everyday life, an ever-increasing yearly incidence of serious accidents at the plants can be expected.