N reactor level 1 probabilistic risk assessment

It was recommended in 1982 that a Probabilistic Risk Assessment should be performed on the N Reactor. Thus, a three-level Probabilistic Risk Assessment study was initiated from this recommendation. This report documents work completed for the Level 1 Probabilistic Risk Assessment by describing the methodology used, the assumptions made, the analysis performed, and the final results. The four primary objectives that were fulfilled successfully by the Level 1 Probabilistic Risk Assessment included the following: identification of the plant features that are the most important contributors to the N Reactor fuel-damage frequency; development of plant logic models for use in analyzing safety and reliability issues; identification of dominant N Reactor accident sequences and their frequencies for input into the Level 2/3 Probabilistic Risk Assessment and external events analyses; and establishment of a Westinghouse Hanford company team with demonstrated expertise in performing risk and reliability analyses. 90 figs., 60 tabs.