Risk regulation for nuclear power plants: Probability and analytical uncertainties

The quantification of the residual risk for nuclear power plants was motivated by an early evaluation of the potential losses following an accidental radioactive release (USAEC, 1957). To be able to judge the likelihood of such an event, the US Nuclear Regulatory Commission sponsored the Reactor Safety Study (USNRC, 1975), whose goal was to compute the probabilities and the consequences of different types of reactor accidents. The PRA method involves three phases; system reliability analysis, in which the goal is to analyze the initial challenges and system response. The result is the probability of core melt per type of accident, initiating event, etc., containment analysis, in which the goal is to analyze the core melt phenomena and containment response. The result is a description of the accident releases, also called the source term, and consequence analysis, in which the goal is to analyze weather, population, and exposure pathways. The result is an assessment of the potential health effects and property damage (USNRC, 1983c)