In the late 1980s, a level III probabilistic risk assessment (PRA) was performed for the N Reactor, a U.S. Department of Energy (DOE) production reactor located on the Hanford site in Washington State. The PRA objectives were to assess the risks to the public and to the Hanford on-site workers posed by the operation of the N Reactor, to compare those risks to proposed DOE nuclear safety guidelines, and to identify risk-reduction changes to the plant. State-of-the-art methodology was employed based largely on the methods developed by Sandia National Laboratories for the U. S. Nuclear Regulatory Commission in support of the NUREG-1150 study of five commercial nuclear power plants. The structure of the probabilistic models allowed complex interactions and dependencies between systems to be explicitly considered. Latin hypercube sampling techniques were used to develop uncertainty distributions for the risks associated with postulated core damage events initiated by fire, seismic, and internal events as well as the overall combined risk. The risk results show that the N Reactor meets the proposed DOE nuclear safety guidelines and compares favorably to the commercial nuclear power plants considered in the NUREG-1150 analysis.